blob: 43db2472887f6aff60b65783557f6c5a2d67fd15 [file] [log] [blame]
mbed TLS ChangeLog (Sorted per branch, date)
= Mbed TLS 3.0.0 branch released 2021-07-07
API changes
* Remove HAVEGE module.
The design of HAVEGE makes it unsuitable for microcontrollers. Platforms
with a more complex CPU usually have an operating system interface that
provides better randomness. Instead of HAVEGE, declare OS or hardware RNG
interfaces with mbedtls_entropy_add_source() and/or use an entropy seed
file created securely during device provisioning. See for
more information.
* Add missing const attributes to API functions.
* Remove helpers for the transition from Mbed TLS 1.3 to Mbed TLS 2.0: the
header compat-1.3.h and the script
* Remove certs module from the API.
Transfer keys and certificates embedded in the library to the test
component. This contributes to minimizing library API and discourages
users from using unsafe keys in production.
* Move alt helpers and definitions.
Various helpers and definitions available for use in alt implementations
have been moved out of the include/ directory and into the library/
directory. The files concerned are ecp_internal.h and rsa_internal.h
which have also been renamed to ecp_internal_alt.h and rsa_alt_helpers.h
* Move internal headers.
Header files that were only meant for the library's internal use and
were not meant to be used in application code have been moved out of
the include/ directory. The headers concerned are bn_mul.h, aesni.h,
padlock.h, entropy_poll.h and *_internal.h.
* Drop support for parsing SSLv2 ClientHello
* Drop support for SSLv3 (MBEDTLS_SSL_PROTO_SSL3).
* Drop support for TLS record-level compression (MBEDTLS_ZLIB_SUPPORT).
* Drop support for RC4 TLS ciphersuites.
* Drop support for single-DES ciphersuites.
* Update AEAD output size macros to bring them in line with the PSA Crypto
API version 1.0 spec. This version of the spec parameterizes them on the
key type used, as well as the key bit-size in the case of
* Add configuration option MBEDTLS_X509_REMOVE_INFO which
removes the mbedtls_x509_*_info(), mbedtls_debug_print_crt()
as well as other functions and constants only used by
those functions. This reduces the code footprint by
several kB.
returned from the public SSL API.
* The output parameter of mbedtls_sha512_finish, mbedtls_sha512,
mbedtls_sha256_finish and mbedtls_sha256 now has a pointer type
rather than array type. This removes spurious warnings in some compilers
when outputting a SHA-384 or SHA-224 hash into a buffer of exactly
the hash size.
* Remove the MBEDTLS_TEST_NULL_ENTROPY config option. Fixes #4388.
* The interface of the GCM module has changed to remove restrictions on
how the input to multipart operations is broken down. mbedtls_gcm_finish()
now takes extra output parameters for the last partial output block.
mbedtls_gcm_update() now takes extra parameters for the output length.
The software implementation always produces the full output at each
call to mbedtls_gcm_update(), but alternative implementations activated
by MBEDTLS_GCM_ALT may delay partial blocks to the next call to
mbedtls_gcm_update() or mbedtls_gcm_finish(). Furthermore, applications
no longer pass the associated data to mbedtls_gcm_starts(), but to the
new function mbedtls_gcm_update_ad().
These changes are backward compatible for users of the cipher API.
* Replace MBEDTLS_SHA512_NO_SHA384 config option with MBEDTLS_SHA384_C.
This separates config option enabling the SHA384 algorithm from option
enabling the SHA512 algorithm. Fixes #4034.
* Introduce MBEDTLS_SHA224_C.
This separates config option enabling the SHA224 algorithm from option
enabling SHA256.
* The getter and setter API of the SSL session cache (used for
session-ID based session resumption) has changed to that of
a key-value store with keys being session IDs and values
being opaque instances of `mbedtls_ssl_session`.
* Remove the mode parameter from RSA operation functions. Signature and
decryption functions now always use the private key and verification and
encryption use the public key. Verification functions also no longer have
RNG parameters.
* Modify semantics of `mbedtls_ssl_conf_[opaque_]psk()`:
In Mbed TLS 2.X, the API prescribes that later calls overwrite
the effect of earlier calls. In Mbed TLS 3.0, calling
`mbedtls_ssl_conf_[opaque_]psk()` more than once will fail,
leaving the PSK that was configured first intact.
Support for more than one PSK may be added in 3.X.
* The function mbedtls_x509write_csr_set_extension() has an extra parameter
which allows to mark an extension as critical. Fixes #4055.
* For multi-part AEAD operations with the cipher module, calling
mbedtls_cipher_finish() is now mandatory. Previously the documentation
was unclear on this point, and this function happened to never do
anything with the currently implemented AEADs, so in practice it was
possible to skip calling it, which is no longer supported.
* The option MBEDTLS_ECP_FIXED_POINT_OPTIM use pre-computed comb tables
instead of computing tables in runtime. Thus, this option now increase
code size, and it does not increase RAM usage in runtime anymore.
* Remove the SSL APIs mbedtls_ssl_get_input_max_frag_len() and
mbedtls_ssl_get_output_max_frag_len(), and add a new API
mbedtls_ssl_get_max_in_record_payload(), complementing the existing
Uses of mbedtls_ssl_get_input_max_frag_len() and
mbedtls_ssl_get_input_max_frag_len() should be replaced by
mbedtls_ssl_get_max_in_record_payload() and
mbedtls_ssl_get_max_out_record_payload(), respectively.
* mbedtls_rsa_init() now always selects the PKCS#1v1.5 encoding for an RSA
key. To use an RSA key with PSS or OAEP, call mbedtls_rsa_set_padding()
after initializing the context. mbedtls_rsa_set_padding() now returns an
error if its parameters are invalid.
configuration function mbedtls_ssl_conf_preference_order(). Fixes #4398.
* Instead of accessing the len field of a DHM context, which is no longer
supported, use the new function mbedtls_dhm_get_len() .
* In modules that implement cryptographic hash functions, many functions
mbedtls_xxx() now return int instead of void, and the corresponding
function mbedtls_xxx_ret() which was identical except for returning int
has been removed. This also concerns mbedtls_xxx_drbg_update(). See the
migration guide for more information. Fixes #4212.
* For all functions that take a random number generator (RNG) as a
parameter, this parameter is now mandatory (that is, NULL is not an
acceptable value). Functions which previously accepted NULL and now
reject it are: the X.509 CRT and CSR writing functions; the PK and RSA
sign and decrypt function; mbedtls_rsa_private(); the functions
in DHM and ECDH that compute the shared secret; the scalar multiplication
functions in ECP.
* The following functions now require an RNG parameter:
mbedtls_ecp_check_pub_priv(), mbedtls_pk_check_pair(),
mbedtls_pk_parse_key(), mbedtls_pk_parse_keyfile().
* mbedtls_ssl_conf_export_keys_ext_cb() and
mbedtls_ssl_conf_export_keys_cb() have been removed and
replaced by a new API mbedtls_ssl_set_export_keys_cb().
Raw keys and IVs are no longer passed to the callback.
Further, callbacks now receive an additional parameter
indicating the type of secret that's being exported,
paving the way for the larger number of secrets
in TLS 1.3. Finally, the key export callback and
context are now connection-specific.
* Signature functions in the RSA and PK modules now require the hash
length parameter to be the size of the hash input. For RSA signatures
other than raw PKCS#1 v1.5, this must match the output size of the
specified hash algorithm.
* The functions mbedtls_pk_sign(), mbedtls_pk_sign_restartable(),
mbedtls_ecdsa_write_signature() and
mbedtls_ecdsa_write_signature_restartable() now take an extra parameter
indicating the size of the output buffer for the signature.
* Implement one-shot cipher functions, psa_cipher_encrypt and
psa_cipher_decrypt, according to the PSA Crypto API 1.0.0
* Direct access to fields of structures declared in public headers is no
longer supported except for fields that are documented public. Use accessor
functions instead. For more information, see the migration guide entry
"Most structure fields are now private".
* mbedtls_ssl_get_session_pointer() has been removed, and
mbedtls_ssl_{set,get}_session() may now only be called once for any given
SSL context.
Default behavior changes
* Enable by default the functionalities which have no reason to be disabled.
They are: ARIA block cipher, CMAC mode, elliptic curve J-PAKE library and
Key Wrapping mode as defined in NIST SP 800-38F. Fixes #4036.
* Some default policies for X.509 certificate verification and TLS have
changed: curves and hashes weaker than 255 bits are no longer accepted
by default. The default order in TLS now favors faster curves over larger
Requirement changes
* The library now uses the %zu format specifier with the printf() family of
functions, so requires a toolchain that supports it. This change does not
affect the maintained LTS branches, so when contributing changes please
bear this in mind and do not add them to backported code.
* If you build the development version of Mbed TLS, rather than an official
release, some configuration-independent files are now generated at build
time rather than checked into source control. This includes some library
source files as well as the Visual Studio solution. Perl, Python 3 and a
C compiler for the host platform are required. See “Generated source files
in the development branch” in for more information.
* Refresh the minimum supported versions of tools to build the
library. CMake versions older than 3.10.2 and Python older
than 3.6 are no longer supported.
compile-time option, which was off by default. Users should not trust
certificates signed with SHA-1 due to the known attacks against SHA-1.
If needed, SHA-1 certificates can still be verified by using a custom
verification profile.
* Removed deprecated things in psa/crypto_compat.h. Fixes #4284
* Removed deprecated functions from hashing modules. Fixes #4280.
* Remove PKCS#11 library wrapper. PKCS#11 has limited functionality,
lacks automated tests and has scarce documentation. Also, PSA Crypto
provides a more flexible private key management.
More details on PCKS#11 wrapper removal can be found in the mailing list
* Remove deprecated error codes. Fix #4283
* Remove MBEDTLS_ENABLE_WEAK_CIPHERSUITES configuration option. Fixes #4416.
compile-time option. This option has been inactive for a long time.
Please use the `lifetime` parameter of `mbedtls_ssl_ticket_setup()`
* Remove the following deprecated functions and constants of hex-encoded
primes based on RFC 5114 and RFC 3526 from library code and tests:
mbedtls_aes_encrypt(), mbedtls_aes_decrypt(), mbedtls_mpi_is_prime(),
mbedtls_cipher_auth_encrypt(), mbedtls_cipher_auth_decrypt(),
mbedtls_ctr_drbg_update(), mbedtls_hmac_drbg_update(),
mbedtls_ecdsa_write_signature_det(), mbedtls_ecdsa_sign_det(),
mbedtls_ssl_conf_dh_param(), mbedtls_ssl_get_max_frag_len(),
Remove the deprecated file: include/mbedtls/net.h. Fixes #4282.
* Remove MBEDTLS_SSL_MAX_CONTENT_LEN configuration option, since
it. Fixes #4362.
* Remove the MBEDTLS_SSL_RECORD_CHECKING option and enable by default its
previous action. Fixes #4361.
* Remove support for TLS 1.0, TLS 1.1 and DTLS 1.0, as well as support for
CBC record splitting, fallback SCSV, and the ability to configure
ciphersuites per version, which are no longer relevant. This removes the
configuration options MBEDTLS_SSL_PROTO_TLS1,
MBEDTLS_SSL_FALLBACK_SCSV as well as the functions
mbedtls_ssl_get_key_exchange_md_ssl_tls(), mbedtls_ssl_conf_fallback(),
and mbedtls_ssl_conf_ciphersuites_for_version(). Fixes #4286.
* The RSA module no longer supports private-key operations with the public
key and vice versa.
* Remove the MBEDTLS_SSL_DTLS_BADMAC_LIMIT config.h option. Fixes #4403.
* Remove all the 3DES ciphersuites:
MBEDTLS_REMOVE_3DES_CIPHERSUITES option which is no longer relevant.
Fixes #4367.
* Remove the MBEDTLS_X509_ALLOW_EXTENSIONS_NON_V3 option and let the code
behave as if it was always disabled. Fixes #4386.
* Remove MBEDTLS_ECDH_LEGACY_CONTEXT config option since this was purely for
backward compatibility which is no longer supported. Addresses #4404.
* Remove the following macros: MBEDTLS_CHECK_PARAMS,
option. The mbedtls_x509_crt_parse_der_with_ext_cb() is the way to go for
migration path. Fixes #4378.
* Remove the MBEDTLS_X509_CHECK_KEY_USAGE and
MBEDTLS_X509_CHECK_EXTENDED_KEY_USAGE config.h options and let the code
behave as if they were always enabled. Fixes #4405.
* MBEDTLS_ECP_MAX_BITS is no longer a configuration option because it is
now determined automatically based on supported curves.
* Remove the following functions: mbedtls_timing_self_test(),
mbedtls_hardclock_poll(), mbedtls_timing_hardclock() and
mbedtls_set_alarm(). Fixes #4083.
* The configuration option MBEDTLS_ECP_NO_INTERNAL_RNG has been removed as
it no longer had any effect.
* Remove all support for MD2, MD4, RC4, Blowfish and XTEA. This removes the
corresponding modules and all their APIs and related configuration
options. Fixes #4084.
* Remove MBEDTLS_SSL_TRUNCATED_HMAC and also remove
MBEDTLS_SSL_TRUNCATED_HMAC_COMPAT config option. Users are better served by
using a CCM-8 ciphersuite than a CBC ciphersuite with truncated HMAC.
See issue #4341 for more details.
* Remove the compile-time option
* Add mbedtls_rsa_rsassa_pss_sign_ext() function allowing to generate a
signature with a specific salt length. This function allows to validate
test cases provided in the NIST's CAVP test suite. Contributed by Cédric
Meuter in PR #3183.
* Added support for built-in driver keys through the PSA opaque crypto
driver interface. Refer to the documentation of
* Implement psa_sign_message() and psa_verify_message().
* The multi-part GCM interface (mbedtls_gcm_update() or
mbedtls_cipher_update()) no longer requires the size of partial inputs to
be a multiple of 16.
* The multi-part GCM interface now supports chunked associated data through
multiple calls to mbedtls_gcm_update_ad().
* The new function mbedtls_mpi_random() generates a random value in a
given range uniformly.
* Alternative implementations of the AES, DHM, ECJPAKE, ECP, RSA and timing
modules had undocumented constraints on their context types. These
constraints have been relaxed.
See docs/architecture/ for the remaining
* The new functions mbedtls_dhm_get_len() and mbedtls_dhm_get_bitlen()
query the size of the modulus in a Diffie-Hellman context.
* The new function mbedtls_dhm_get_value() copy a field out of a
Diffie-Hellman context.
* Use the new function mbedtls_ecjpake_set_point_format() to select the
point format for ECJPAKE instead of accessing the point_format field
directly, which is no longer supported.
* Implement psa_mac_compute() and psa_mac_verify() as defined in the
PSA Cryptograpy API 1.0.0 specification.
* Fix a bias in the generation of finite-field Diffie-Hellman-Merkle (DHM)
private keys and of blinding values for DHM and elliptic curves (ECP)
computations. Reported by FlorianF89 in #4245.
* Fix a potential side channel vulnerability in ECDSA ephemeral key generation.
An adversary who is capable of very precise timing measurements could
learn partial information about the leading bits of the nonce used for the
signature, allowing the recovery of the private key after observing a
large number of signature operations. This completes a partial fix in
Mbed TLS 2.20.0.
* An adversary with access to precise enough information about memory
accesses (typically, an untrusted operating system attacking a secure
enclave) could recover an RSA private key after observing the victim
performing a single private-key operation. Found and reported by
Zili KOU, Wenjian HE, Sharad Sinha, and Wei ZHANG.
* An adversary with access to precise enough timing information (typically, a
co-located process) could recover a Curve25519 or Curve448 static ECDH key
after inputting a chosen public key and observing the victim performing the
corresponding private-key operation. Found and reported by Leila Batina,
Lukas Chmielewski, Björn Haase, Niels Samwel and Peter Schwabe.
* Fix premature fopen() call in mbedtls_entropy_write_seed_file which may
lead to the seed file corruption in case if the path to the seed file is
equal to MBEDTLS_PLATFORM_STD_NV_SEED_FILE. Contributed by Victor
Krasnoshchok in #3616.
* PSA functions creating a key now return PSA_ERROR_INVALID_ARGUMENT rather
than PSA_ERROR_INVALID_HANDLE when the identifier specified for the key
to create is not valid, bringing them in line with version 1.0.0 of the
specification. Fix #4271.
* Add printf function attributes to mbedtls_debug_print_msg to ensure we
get printf format specifier warnings.
* PSA functions other than psa_open_key now return PSA_ERROR_INVALID_HANDLE
rather than PSA_ERROR_DOES_NOT_EXIST for an invalid handle, bringing them
in line with version 1.0.0 of the specification. Fix #4162.
* Fix a bug in ECDSA that would cause it to fail when the hash is all-bits
zero. Fixes #1792
* Fix some cases in the bignum module where the library constructed an
unintended representation of the value 0 which was not processed
correctly by some bignum operations. This could happen when
mbedtls_mpi_read_string() was called on "-0", or when
mbedtls_mpi_mul_mpi() and mbedtls_mpi_mul_int() was called with one of
the arguments being negative and the other being 0. Fixes #4643.
* Fix a compilation error when MBEDTLS_ECP_RANDOMIZE_MXZ_ALT is
defined. Fixes #4217.
* Fix an incorrect error code when parsing a PKCS#8 private key.
* In a TLS client, enforce the Diffie-Hellman minimum parameter size
set with mbedtls_ssl_conf_dhm_min_bitlen() precisely. Before, the
minimum size was rounded down to the nearest multiple of 8.
* In library/net_sockets.c, _POSIX_C_SOURCE and _XOPEN_SOURCE are
defined to specific values. If the code is used in a context
where these are already defined, this can result in a compilation
error. Instead, assume that if they are defined, the values will
be adequate to build Mbed TLS.
* With MBEDTLS_PSA_CRYPTO_C disabled, some functions were getting built
nonetheless, resulting in undefined reference errors when building a
shared library. Reported by Guillermo Garcia M. in #4411.
* The cipher suite TLS-RSA-WITH-CAMELLIA-256-GCM-SHA384 was not available
when SHA-1 was disabled and was offered when SHA-1 was enabled but SHA-384
was disabled. Fix the dependency. Fixes #4472.
* Do not offer SHA384 cipher suites when SHA-384 is disabled. Fixes #4499.
* Fix test suite code on platforms where int32_t is not int, such as
Arm Cortex-M. Fixes #4530.
* Fix some issues affecting MBEDTLS_ARIA_ALT implementations: a misplaced
directive in a header and a missing initialization in the self-test.
* Fix a missing initialization in the Camellia self-test, affecting
MBEDTLS_CAMELLIA_ALT implementations.
* Restore the ability to configure PSA via Mbed TLS options to support RSA
key pair operations but exclude RSA key generation. When MBEDTLS_GENPRIME
is not defined PSA will no longer attempt to use mbedtls_rsa_gen_key().
Fixes #4512.
* Fix a regression introduced in 2.24.0 which broke (D)TLS CBC ciphersuites
(when the encrypt-then-MAC extension is not in use) with some ALT
implementations of the underlying hash (SHA-1, SHA-256, SHA-384), causing
the affected side to wrongly reject valid messages. Fixes #4118.
* Remove outdated check-config.h check that prevented implementing the
timing module on Mbed OS. Fixes #4633.
* Fix PSA_ALG_TLS12_PRF and PSA_ALG_TLS12_PSK_TO_MS being too permissive
about missing inputs.
* Fix mbedtls_net_poll() and mbedtls_net_recv_timeout() often failing with
MBEDTLS_ERR_NET_POLL_FAILED on Windows. Fixes #4465.
* Fix a resource leak in a test suite with an alternative AES
implementation. Fixes #4176.
* Fix a crash in mbedtls_mpi_debug_mpi on a bignum having 0 limbs. This
could notably be triggered by setting the TLS debug level to 3 or above
and using a Montgomery curve for the key exchange. Reported by lhuang04
in #4578. Fixes #4608.
* psa_verify_hash() was relying on implementation-specific behavior of
mbedtls_rsa_rsassa_pss_verify() and was causing failures in some _ALT
implementations. This reliance is now removed. Fixes #3990.
* Disallow inputs of length different from the corresponding hash when
signing or verifying with PSA_ALG_RSA_PSS (The PSA Crypto API mandates
that PSA_ALG_RSA_PSS uses the same hash throughout the algorithm.)
* Fix a null pointer dereference when mbedtls_mpi_exp_mod() was called with
A=0 represented with 0 limbs. Up to and including Mbed TLS 2.26, this bug
could not be triggered by code that constructed A with one of the
mbedtls_mpi_read_xxx functions (including in particular TLS code) since
those always built an mpi object with at least one limb.
Credit to OSS-Fuzz. Fixes #4641.
* Fix mbedtls_mpi_gcd(G,A,B) when the value of B is zero. This had no
effect on Mbed TLS's internal use of mbedtls_mpi_gcd(), but may affect
applications that call mbedtls_mpi_gcd() directly. Fixes #4642.
* The PSA API no longer allows the creation or destruction of keys with a
read-only lifetime. The persistence level PSA_KEY_PERSISTENCE_READ_ONLY
can now only be used as intended, for keys that cannot be modified through
normal use of the API.
* When MBEDTLS_PSA_CRYPTO_SPM is enabled, crypto_spe.h was not included
in all the right places. Include it from crypto_platform.h, which is
the natural place. Fixes #4649.
* Fix which alert is sent in some cases to conform to the
applicable RFC: on an invalid Finished message value, an
invalid max_fragment_length extension, or an
unsupported extension used by the server.
* Correct (change from 12 to 13 bytes) the value of the macro describing the
maximum nonce length returned by psa_aead_generate_nonce().
* Fix the setting of the read timeout in the DTLS sample programs.
* Add extra printf compiler warning flags to builds.
* Fix memsan build false positive in x509_crt.c with clang 11
* There is ongoing work for the next release (= Mbed TLS 3.0.0 branch to
be released 2021-xx-xx), including various API-breaking changes.
* Alternative implementations of CMAC may now opt to not support 3DES as a
CMAC block cipher, and still pass the CMAC self test.
* Remove the AES sample application programs/aes/aescrypt2 which shows
bad cryptographic practice. Fix #1906.
* Remove configs/config-psa-crypto.h, which no longer had any intended
differences from the default configuration, but had accidentally diverged.
* When building the test suites with GNU make, invoke python3 or python, not
python2, which is no longer supported upstream.
* fix build failure on MinGW toolchain when __USE_MING_ANSI_STDIO is on.
When that flag is on, standard GNU C printf format specifiers
should be used.
MBEDTLS_SSL_TLS1_3_PADDING_GRANULARITY with a new single unified option
* Reduce the default value of MBEDTLS_ECP_WINDOW_SIZE. This reduces RAM usage
during ECC operations at a negligible performance cost.
* mbedtls_mpi_read_binary(), mbedtls_mpi_read_binary_le() and
mbedtls_mpi_read_string() now construct an mbedtls_mpi object with 0 limbs
when their input has length 0. Note that this is an implementation detail
and can change at any time, so this change should be transparent, but it
may result in mbedtls_mpi_write_binary() or mbedtls_mpi_write_string()
now writing an empty string where it previously wrote one or more
zero digits when operating from values constructed with an mpi_read
function and some mpi operations.
* Add CMake package config generation for CMake projects consuming Mbed TLS.
* config.h has been split into build_info.h and mbedtls_config.h
build_info.h is intended to be included from C code directly, while
mbedtls_config.h is intended to be edited by end users wishing to
change the build configuration, and should generally only be included from
* The handling of MBEDTLS_CONFIG_FILE has been moved into build_info.h.
* A config file version symbol, MBEDTLS_CONFIG_VERSION was introduced.
Defining it to a particular value will ensure that Mbed TLS interprets
the config file in a way that's compatible with the config file format
used by the Mbed TLS release whose MBEDTLS_VERSION_NUMBER has the same
The only value supported by Mbed TLS 3.0.0 is 0x03000000.
* Various changes to which alert and/or error code may be returned
* during the TLS handshake.
* Implicitly add PSA_KEY_USAGE_SIGN_MESSAGE key usage policy flag when
when PSA_KEY_USAGE_VERIFY_HASH flag is set. This usage flag extension
is also applied when loading a key from storage.
= mbed TLS 2.26.0 branch released 2021-03-08
API changes
* Renamed the PSA Crypto API output buffer size macros to bring them in line
with version 1.0.0 of the specification.
* The API glue function mbedtls_ecc_group_of_psa() now takes the curve size
in bits rather than bytes, with an additional flag to indicate if the
size may have been rounded up to a whole number of bytes.
* Renamed the PSA Crypto API AEAD tag length macros to bring them in line
with version 1.0.0 of the specification.
Default behavior changes
* In mbedtls_rsa_context objects, the ver field was formerly documented
as always 0. It is now reserved for internal purposes and may take
different values.
New deprecations
PSA_ALG_TLS12_PSK_TO_MS_MAX_PSK_LEN have been renamed, and the old names
have been renamed, and the old names deprecated.
* The PSA crypto subsystem can now use HMAC_DRBG instead of CTR_DRBG.
CTR_DRBG is used by default if it is available, but you can override
this choice by setting MBEDTLS_PSA_HMAC_DRBG_MD_TYPE at compile time.
Fix #3354.
* Automatic fallback to a software implementation of ECP when
MBEDTLS_ECP_xxx_ALT accelerator hooks are in use can now be turned off
through setting the new configuration flag MBEDTLS_ECP_NO_FALLBACK.
* The PSA crypto subsystem can now be configured to use less static RAM by
tweaking the setting for the maximum amount of keys simultaneously in RAM.
MBEDTLS_PSA_KEY_SLOT_COUNT sets the maximum number of volatile keys that
can exist simultaneously. It has a sensible default if not overridden.
* Partial implementation of the PSA crypto driver interface: Mbed TLS can
now use an external random generator instead of the library's own
entropy collection and DRBG code. Enable MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG
and see the documentation of mbedtls_psa_external_get_random() for details.
* Applications using both mbedtls_xxx and psa_xxx functions (for example,
applications using TLS and MBEDTLS_USE_PSA_CRYPTO) can now use the PSA
random generator with mbedtls_xxx functions. See the documentation of
mbedtls_psa_get_random() for details.
* In the PSA API, the policy for a MAC or AEAD algorithm can specify a
minimum MAC or tag length thanks to the new wildcards
* Fix a security reduction in CTR_DRBG when the initial seeding obtained a
nonce from entropy. Applications were affected if they called
mbedtls_ctr_drbg_set_nonce_len(), if they called
mbedtls_ctr_drbg_set_entropy_len() with a size that was 3/2 times the key
length, or when the entropy module uses SHA-256 and CTR_DRBG uses AES-256.
In such cases, a random nonce was necessary to achieve the advertised
security strength, but the code incorrectly used a constant instead of
entropy from the nonce.
Found by John Stroebel in #3819 and fixed in #3973.
* Fix a buffer overflow in mbedtls_mpi_sub_abs() when calculating
|A| - |B| where |B| is larger than |A| and has more limbs (so the
function should return MBEDTLS_ERR_MPI_NEGATIVE_VALUE). Only
applications calling mbedtls_mpi_sub_abs() directly are affected:
all calls inside the library were safe since this function is
only called with |A| >= |B|. Reported by Guido Vranken in #4042.
* Fix an errorneous estimation for an internal buffer in
mbedtls_pk_write_key_pem(). If MBEDTLS_MPI_MAX_SIZE is set to an odd
value the function might fail to write a private RSA keys of the largest
supported size.
Found by Daniel Otte, reported in #4093 and fixed in #4094.
* Fix a stack buffer overflow with mbedtls_net_poll() and
mbedtls_net_recv_timeout() when given a file descriptor that is
beyond FD_SETSIZE. Reported by FigBug in #4169.
* Guard against strong local side channel attack against base64 tables by
making access aceess to them use constant flow code.
* Fix use-after-scope error in programs/ssl/ssl_client2.c and ssl_server2.c
* Fix memory leak that occured when calling psa_close_key() on a
wrapped key with MBEDTLS_PSA_CRYPTO_SE_C defined.
* Fix an incorrect error code if an RSA private operation glitched.
* Fix a memory leak in an error case in psa_generate_derived_key_internal().
* Fix a resource leak in CTR_DRBG and HMAC_DRBG when MBEDTLS_THREADING_C
is enabled, on platforms where initializing a mutex allocates resources.
This was a regression introduced in the previous release. Reported in
#4017, #4045 and #4071.
* Ensure that calling mbedtls_rsa_free() or mbedtls_entropy_free()
twice is safe. This happens for RSA when some Mbed TLS library functions
fail. Such a double-free was not safe when MBEDTLS_THREADING_C was
enabled on platforms where freeing a mutex twice is not safe.
* Fix a resource leak in a bad-arguments case of mbedtls_rsa_gen_key()
when MBEDTLS_THREADING_C is enabled on platforms where initializing
a mutex allocates resources.
* Fixes a bug where, if the library was configured to include support for
both the old SE interface and the new PSA driver interface, external keys were
not loaded from storage. This was fixed by #3996.
* This change makes 'mbedtls_x509write_crt_set_basic_constraints'
consistent with RFC 5280 which says: "Conforming CAs MUST
include this extension in all CA certificates that contain public keys
used to validate digital signatures on certificates and MUST mark the
extension as critical in such certificates." Previous to this change,
the extension was always marked as non-critical. This was fixed by
* A new library C file psa_crypto_client.c has been created to contain
the PSA code needed by a PSA crypto client when the PSA crypto
implementation is not included into the library.
* On recent enough versions of FreeBSD and DragonFlyBSD, the entropy module
now uses the getrandom syscall instead of reading from /dev/urandom.
= mbed TLS 2.25.0 branch released 2020-12-11
API changes
* The numerical values of the PSA Crypto API macros have been updated to
conform to version 1.0.0 of the specification.
The underlying stream cipher is determined by the key type
* The functions mbedtls_cipher_auth_encrypt() and
mbedtls_cipher_auth_decrypt() no longer accept NIST_KW contexts,
as they have no way to check if the output buffer is large enough.
Please use mbedtls_cipher_auth_encrypt_ext() and
mbedtls_cipher_auth_decrypt_ext() instead. Credit to OSS-Fuzz and
Cryptofuzz. Fixes #3665.
Requirement changes
* Update the minimum required CMake version to 2.8.12. This silences a
warning on CMake 3.19.0. #3801
New deprecations
* PSA_ALG_CHACHA20 and PSA_ALG_ARC4 have been deprecated.
* The functions mbedtls_cipher_auth_encrypt() and
mbedtls_cipher_auth_decrypt() are deprecated in favour of the new
functions mbedtls_cipher_auth_encrypt_ext() and
mbedtls_cipher_auth_decrypt_ext(). Please note that with AEAD ciphers,
these new functions always append the tag to the ciphertext, and include
the tag in the ciphertext length.
* Partial implementation of the new PSA Crypto accelerator APIs. (Symmetric
ciphers, asymmetric signing/verification and key generation, validate_key
entry point, and export_public_key interface.)
* Add support for ECB to the PSA cipher API.
* In PSA, allow using a key declared with a base key agreement algorithm
in combined key agreement and derivation operations, as long as the key
agreement algorithm in use matches the algorithm the key was declared with.
This is currently non-standard behaviour, but expected to make it into a
future revision of the PSA Crypto standard.
* Add MBEDTLS_TARGET_PREFIX CMake variable, which is prefixed to the mbedtls,
mbedcrypto, mbedx509 and apidoc CMake target names. This can be used by
external CMake projects that include this one to avoid CMake target name
clashes. The default value of this variable is "", so default target names
are unchanged.
* Add support for DTLS-SRTP as defined in RFC 5764. Contributed by Johan
Pascal, improved by Ron Eldor.
* In the PSA API, it is no longer necessary to open persistent keys:
operations now accept the key identifier. The type psa_key_handle_t is now
identical to psa_key_id_t instead of being platform-defined. This bridges
the last major gap to compliance with the PSA Cryptography specification
version 1.0.0. Opening persistent keys is still supported for backward
compatibility, but will be deprecated and later removed in future
PSA_CIPHER_IV_MAX_SIZE macros have been added as defined in version
1.0.0 of the PSA Crypto API specification.
* The functions mbedtls_cipher_auth_encrypt() and
mbedtls_cipher_auth_decrypt() would write past the minimum documented
size of the output buffer when used with NIST_KW. As a result, code using
those functions as documented with NIST_KW could have a buffer overwrite
of up to 15 bytes, with consequences ranging up to arbitrary code
execution depending on the location of the output buffer.
* Limit the size of calculations performed by mbedtls_mpi_exp_mod to
MBEDTLS_MPI_MAX_SIZE to prevent a potential denial of service when
generating Diffie-Hellman key pairs. Credit to OSS-Fuzz.
* A failure of the random generator was ignored in mbedtls_mpi_fill_random(),
which is how most uses of randomization in asymmetric cryptography
(including key generation, intermediate value randomization and blinding)
are implemented. This could cause failures or the silent use of non-random
values. A random generator can fail if it needs reseeding and cannot not
obtain entropy, or due to an internal failure (which, for Mbed TLS's own
CTR_DRBG or HMAC_DRBG, can only happen due to a misconfiguration).
* Fix a compliance issue whereby we were not checking the tag on the
algorithm parameters (only the size) when comparing the signature in the
description part of the cert to the real signature. This meant that a
NULL algorithm parameters entry would look identical to an array of REAL
(size zero) to the library and thus the certificate would be considered
valid. However, if the parameters do not match in *any* way then the
certificate should be considered invalid, and indeed OpenSSL marks these
certs as invalid when mbedtls did not.
Many thanks to guidovranken who found this issue via differential fuzzing
and reported it in #3629.
* Zeroising of local buffers and variables which are used for calculations
in mbedtls_pkcs5_pbkdf2_hmac(), mbedtls_internal_sha*_process(),
mbedtls_internal_md*_process() and mbedtls_internal_ripemd160_process()
functions to erase sensitive data from memory. Reported by
Johan Malmgren and Johan Uppman Bruce from Sectra.
* Fix an invalid (but nonzero) return code from mbedtls_pk_parse_subpubkey()
when the input has trailing garbage. Fixes #2512.
* Fix build failure in configurations where MBEDTLS_USE_PSA_CRYPTO is
enabled but ECDSA is disabled. Contributed by jdurkop. Fixes #3294.
* Include the psa_constant_names generated source code in the source tree
instead of generating it at build time. Fixes #3524.
* Fix rsa_prepare_blinding() to retry when the blinding value is not
invertible (mod N), instead of returning MBEDTLS_ERR_RSA_RNG_FAILED. This
addresses a regression but is rare in practice (approx. 1 in 2/sqrt(N)).
Found by Synopsys Coverity, fix contributed by Peter Kolbus (Garmin).
Fixes #3647.
* Use socklen_t on Android and other POSIX-compliant system
* Fix the build when the macro _GNU_SOURCE is defined to a non-empty value.
Fix #3432.
* Consistently return PSA_ERROR_INVALID_ARGUMENT on invalid cipher input
sizes (instead of PSA_ERROR_BAD_STATE in some cases) to make the
psa_cipher_* functions compliant with the PSA Crypto API specification.
* mbedtls_ecp_curve_list() now lists Curve25519 and Curve448 under the names
"x25519" and "x448". These curves support ECDH but not ECDSA. If you need
only the curves that support ECDSA, filter the list with
* Fix psa_generate_key() returning an error when asked to generate
an ECC key pair on Curve25519 or secp244k1.
* Fix psa_key_derivation_output_key() to allow the output of a combined key
agreement and subsequent key derivation operation to be used as a key
inside of the PSA Crypto core.
* Fix handling of EOF against 0xff bytes and on platforms with unsigned
chars. Fixes a build failure on platforms where char is unsigned. Fixes
* Fix an off-by-one error in the additional data length check for
CCM, which allowed encryption with a non-standard length field.
Fixes #3719.
* Correct the default IV size for mbedtls_cipher_info_t structures using
MBEDTLS_MODE_ECB to 0, since ECB mode ciphers don't use IVs.
* Make arc4random_buf available on NetBSD and OpenBSD when _POSIX_C_SOURCE is
defined. Fix contributed in #3571.
* Fix conditions for including string.h in error.c. Fixes #3866.
* psa_set_key_id() now also sets the lifetime to persistent for keys located
in a secure element.
* Attempting to create a volatile key with a non-zero key identifier now
fails. Previously the key identifier was just ignored when creating a
volatile key.
* Attempting to create or register a key with a key identifier in the vendor
range now fails.
* Fix build failures on GCC 11. Fixes #3782.
* Add missing arguments of debug message in mbedtls_ssl_decrypt_buf.
* Fix a memory leak in mbedtls_mpi_sub_abs() when the result was negative
(an error condition) and the second operand was aliased to the result.
* Fix a case in elliptic curve arithmetic where an out-of-memory condition
could go undetected, resulting in an incorrect result.
* In CTR_DRBG and HMAC_DRBG, don't reset the reseed interval in seed().
Fixes #2927.
* In PEM writing functions, fill the trailing part of the buffer with null
bytes. This guarantees that the corresponding parsing function can read
the buffer back, which was the case for mbedtls_x509write_{crt,csr}_pem
until this property was inadvertently broken in Mbed TLS 2.19.0.
Fixes #3682.
* Fix a build failure that occurred with the MBEDTLS_AES_SETKEY_DEC_ALT
option on. In this configuration key management methods that are required
for MBEDTLS_CIPHER_MODE_XTS were excluded from the build and made it fail.
Fixes #3818. Reported by John Stroebel.
* Reduce stack usage significantly during sliding window exponentiation.
Reported in #3591 and fix contributed in #3592 by Daniel Otte.
* The PSA persistent storage format is updated to always store the key bits
attribute. No automatic upgrade path is provided. Previously stored keys
must be erased, or manually upgraded based on the key storage format
specification (docs/architecture/
Fixes #3740.
* Remove the zeroization of a pointer variable in AES rounds. It was valid
but spurious and misleading since it looked like a mistaken attempt to
zeroize the pointed-to buffer. Reported by Antonio de la Piedra, CEA
Leti, France.
= mbed TLS 2.24.0 branch released 2020-09-01
API changes
* In the PSA API, rename the types of elliptic curve and Diffie-Hellman
group families to psa_ecc_family_t and psa_dh_family_t, in line with the
PSA Crypto API specification version 1.0.0.
Rename associated macros as well:
PSA_ECC_CURVE_xxx renamed to PSA_ECC_FAMILY_xxx
PSA_DH_GROUP_xxx renamed to PSA_DH_FAMILY_xxx
Default behavior changes
* Stop storing persistent information about externally stored keys created
through PSA Crypto with a volatile lifetime. Reported in #3288 and
contributed by Steven Cooreman in #3382.
* The new function mbedtls_ecp_write_key() exports private ECC keys back to
a byte buffer. It is the inverse of the existing mbedtls_ecp_read_key().
* Support building on e2k (Elbrus) architecture: correctly enable
-Wformat-signedness, and fix the code that causes signed-one-bit-field
and sign-compare warnings. Contributed by makise-homura (Igor Molchanov)
* Fix a vulnerability in the verification of X.509 certificates when
matching the expected common name (the cn argument of
mbedtls_x509_crt_verify()) with the actual certificate name: when the
subjecAltName extension is present, the expected name was compared to any
name in that extension regardless of its type. This means that an
attacker could for example impersonate a 4-bytes or 16-byte domain by
getting a certificate for the corresponding IPv4 or IPv6 (this would
require the attacker to control that IP address, though). Similar attacks
using other subjectAltName name types might be possible. Found and
reported by kFYatek in #3498.
* When checking X.509 CRLs, a certificate was only considered as revoked if
its revocationDate was in the past according to the local clock if
available. In particular, on builds without MBEDTLS_HAVE_TIME_DATE,
certificates were never considered as revoked. On builds with
MBEDTLS_HAVE_TIME_DATE, an attacker able to control the local clock (for
example, an untrusted OS attacking a secure enclave) could prevent
revocation of certificates via CRLs. Fixed by no longer checking the
revocationDate field, in accordance with RFC 5280. Reported by
yuemonangong in #3340. Reported independently and fixed by
Raoul Strackx and Jethro Beekman in #3433.
* In (D)TLS record decryption, when using a CBC ciphersuites without the
Encrypt-then-Mac extension, use constant code flow memory access patterns
to extract and check the MAC. This is an improvement to the existing
countermeasure against Lucky 13 attacks. The previous countermeasure was
effective against network-based attackers, but less so against local
attackers. The new countermeasure defends against local attackers, even
if they have access to fine-grained measurements. In particular, this
fixes a local Lucky 13 cache attack found and reported by Tuba Yavuz,
Farhaan Fowze, Ken (Yihan) Bai, Grant Hernandez, and Kevin Butler
(University of Florida) and Dave Tian (Purdue University).
* Fix side channel in RSA private key operations and static (finite-field)
Diffie-Hellman. An adversary with precise enough timing and memory access
information (typically an untrusted operating system attacking a secure
enclave) could bypass an existing counter-measure (base blinding) and
potentially fully recover the private key.
* Fix a 1-byte buffer overread in mbedtls_x509_crl_parse_der().
Credit to OSS-Fuzz for detecting the problem and to Philippe Antoine
for pinpointing the problematic code.
* Zeroising of plaintext buffers in mbedtls_ssl_read() to erase unused
application data from memory. Reported in #689 by
Johan Uppman Bruce of Sectra.
* Library files installed after a CMake build no longer have execute
* Use local labels in mbedtls_padlock_has_support() to fix an invalid symbol
redefinition if the function is inlined.
Reported in #3451 and fix contributed in #3452 by okhowang.
* Fix the endianness of Curve25519 keys imported/exported through the PSA
APIs. psa_import_key and psa_export_key will now correctly expect/output
Montgomery keys in little-endian as defined by RFC7748. Contributed by
Steven Cooreman in #3425.
* Fix build errors when the only enabled elliptic curves are Montgomery
curves. Raised by signpainter in #941 and by Taiki-San in #1412. This
also fixes missing declarations reported by Steven Cooreman in #1147.
* Fix self-test failure when the only enabled short Weierstrass elliptic
curve is secp192k1. Fixes #2017.
* PSA key import will now correctly import a Curve25519/Curve448 public key
instead of erroring out. Contributed by Steven Cooreman in #3492.
* Use arc4random_buf on NetBSD instead of rand implementation with cyclical
lower bits. Fix contributed in #3540.
* Fix a memory leak in mbedtls_md_setup() when using HMAC under low memory
conditions. Reported and fix suggested by Guido Vranken in #3486.
* Fix bug in redirection of unit test outputs on platforms where stdout is
defined as a macro. First reported in #2311 and fix contributed in #3528.
* Only pass -Wformat-signedness to versions of GCC that support it. Reported
in #3478 and fix contributed in #3479 by okhowang.
* Reduce the stack consumption of mbedtls_x509write_csr_der() which
previously could lead to stack overflow on constrained devices.
Contributed by Doru Gucea and Simon Leet in #3464.
* Undefine the ASSERT macro before defining it locally, in case it is defined
in a platform header. Contributed by Abdelatif Guettouche in #3557.
* Update copyright notices to use Linux Foundation guidance. As a result,
the copyright of contributors other than Arm is now acknowledged, and the
years of publishing are no longer tracked in the source files. This also
eliminates the need for the lines declaring the files to be part of
MbedTLS. Fixes #3457.
* Add the command line parameter key_pwd to the ssl_client2 and ssl_server2
example applications which allows to provide a password for the key file
specified through the existing key_file argument. This allows the use of
these applications with password-protected key files. Analogously but for
ssl_server2 only, add the command line parameter key_pwd2 which allows to
set a password for the key file provided through the existing key_file2
= mbed TLS 2.23.0 branch released 2020-07-01
Default behavior changes
* In the experimental PSA secure element interface, change the encoding of
key lifetimes to encode a persistence level and the location. Although C
prototypes do not effectively change, code calling
psa_register_se_driver() must be modified to pass the driver's location
instead of the keys' lifetime. If the library is upgraded on an existing
device, keys created with the old lifetime value will not be readable or
removable through Mbed TLS after the upgrade.
* New functions in the error module return constant strings for
high- and low-level error codes, complementing mbedtls_strerror()
which constructs a string for any error code, including compound
ones, but requires a writable buffer. Contributed by Gaurav Aggarwal
in #3176.
* The new utility programs/ssl/ssl_context_info prints a human-readable
dump of an SSL context saved with mbedtls_ssl_context_save().
* Add support for midipix, a POSIX layer for Microsoft Windows.
* Add new mbedtls_x509_crt_parse_der_with_ext_cb() routine which allows
parsing unsupported certificate extensions via user provided callback.
Contributed by Nicola Di Lieto <> in #3243 as
a solution to #3241.
* Pass the "certificate policies" extension to the callback supplied to
mbedtls_x509_crt_parse_der_with_ext_cb() if it contains unsupported
policies (#3419).
* Added support to entropy_poll for the kern.arandom syscall supported on
some BSD systems. Contributed by Nia Alarie in #3423.
* Add support for Windows 2000 in net_sockets. Contributed by opatomic. #3239
* Fix a side channel vulnerability in modular exponentiation that could
reveal an RSA private key used in a secure enclave. Noticed by Sangho Lee,
Ming-Wei Shih, Prasun Gera, Taesoo Kim and Hyesoon Kim (Georgia Institute
of Technology); and Marcus Peinado (Microsoft Research). Reported by Raoul
Strackx (Fortanix) in #3394.
* Fix side channel in mbedtls_ecp_check_pub_priv() and
mbedtls_pk_parse_key() / mbedtls_pk_parse_keyfile() (when loading a
private key that didn't include the uncompressed public key), as well as
mbedtls_ecp_mul() / mbedtls_ecp_mul_restartable() when called with a NULL
f_rng argument. An attacker with access to precise enough timing and
memory access information (typically an untrusted operating system
attacking a secure enclave) could fully recover the ECC private key.
Found and reported by Alejandro Cabrera Aldaya and Billy Brumley.
* Fix issue in Lucky 13 counter-measure that could make it ineffective when
hardware accelerators were used (using one of the MBEDTLS_SHAxxx_ALT
macros). This would cause the original Lucky 13 attack to be possible in
those configurations, allowing an active network attacker to recover
plaintext after repeated timing measurements under some conditions.
Reported and fix suggested by Luc Perneel in #3246.
* Fix the Visual Studio Release x64 build configuration for mbedtls itself.
Completes a previous fix in Mbed TLS 2.19 that only fixed the build for
the example programs. Reported in #1430 and fix contributed by irwir.
* Fix undefined behavior in X.509 certificate parsing if the
pathLenConstraint basic constraint value is equal to INT_MAX.
The actual effect with almost every compiler is the intended
behavior, so this is unlikely to be exploitable anywhere. #3192
* Fix issue with a detected HW accelerated record error not being exposed
due to shadowed variable. Contributed by Sander Visser in #3310.
* Avoid NULL pointer dereferencing if mbedtls_ssl_free() is called with a
NULL pointer argument. Contributed by Sander Visser in #3312.
* Fix potential linker errors on dual world platforms by inlining
mbedtls_gcc_group_to_psa(). This allows the pk.c module to link separately
from psa_crypto.c. Fixes #3300.
* Remove dead code in X.509 certificate parsing. Contributed by irwir in
* Include asn1.h in error.c. Fixes #3328 reported by David Hu.
* Fix potential memory leaks in ecp_randomize_jac() and ecp_randomize_mxz()
when PRNG function fails. Contributed by Jonas Lejeune in #3318.
* Remove unused macros from MSVC projects. Reported in #3297 and fix
submitted in #3333 by irwir.
* Add additional bounds checks in ssl_write_client_hello() preventing
output buffer overflow if the configuration declared a buffer that was
too small.
* Set _POSIX_C_SOURCE to at least 200112L in C99 code. Reported in #3420 and
fix submitted in #3421 by Nia Alarie.
* Fix building library/net_sockets.c and the ssl_mail_client program on
NetBSD. Contributed by Nia Alarie in #3422.
* Fix false positive uninitialised variable reported by cpp-check.
Contributed by Sander Visser in #3311.
* Update iv and len context pointers manually when reallocating buffers
using the MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH feature. This caused issues
when receiving a connection with CID, when these fields were shifted
in ssl_parse_record_header().
* Fix warnings about signedness issues in format strings. The build is now
clean of -Wformat-signedness warnings. Contributed by Kenneth Soerensen
in #3153.
* Fix minor performance issue in operations on Curve25519 caused by using a
suboptimal modular reduction in one place. Found and fix contributed by
Aurelien Jarno in #3209.
* Combine identical cases in switch statements in md.c. Contributed
by irwir in #3208.
* Simplify a bounds check in ssl_write_certificate_request(). Contributed
by irwir in #3150.
* Unify the example programs termination to call mbedtls_exit() instead of
using a return command. This has been done to enable customization of the
behavior in bare metal environments.
* Fix mbedtls_x509_dn_gets to escape non-ASCII characters as "?".
Contributed by Koh M. Nakagawa in #3326.
* Use FindPython3 when cmake version >= 3.15.0
* Abort the ClientHello writing function as soon as some extension doesn't
fit into the record buffer. Previously, such extensions were silently
dropped. As a consequence, the TLS handshake now fails when the output
buffer is not large enough to hold the ClientHello.
* The unit tests now rely on header files in tests/include/test and source
files in tests/src. When building with make or cmake, the files in
tests/src are compiled and the resulting object linked into each test
* The ECP module, enabled by `MBEDTLS_ECP_C`, now depends on
`MBEDTLS_CTR_DRBG_C` or `MBEDTLS_HMAC_DRBG_C` for some side-channel
coutermeasures. If side channels are not a concern, this dependency can
be avoided by enabling the new option `MBEDTLS_ECP_NO_INTERNAL_RNG`.
* Align MSVC error flag with GCC and Clang. Contributed by Carlos Gomes
Martinho. #3147
* Remove superfluous assignment in mbedtls_ssl_parse_certificate(). Reported
in #3182 and fix submitted by irwir. #3217
* Fix typo in XTS tests. Reported and fix submitted by Kxuan. #3319
= mbed TLS 2.22.0 branch released 2020-04-14
New deprecations
* Deprecate MBEDTLS_SSL_HW_RECORD_ACCEL that enables function hooks in the
SSL module for hardware acceleration of individual records.
* Deprecate mbedtls_ssl_get_max_frag_len() in favour of
mbedtls_ssl_get_output_max_frag_len() and
mbedtls_ssl_get_input_max_frag_len() to be more precise about which max
fragment length is desired.
* Fix issue in DTLS handling of new associations with the same parameters
(RFC 6347 section 4.2.8): an attacker able to send forged UDP packets to
the server could cause it to drop established associations with
legitimate clients, resulting in a Denial of Service. This could only
happen when MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE was enabled in config.h
(which it is by default).
* Fix side channel in ECC code that allowed an adversary with access to
precise enough timing and memory access information (typically an
untrusted operating system attacking a secure enclave) to fully recover
an ECDSA private key. Found and reported by Alejandro Cabrera Aldaya,
Billy Brumley and Cesar Pereida Garcia. CVE-2020-10932
* Fix a potentially remotely exploitable buffer overread in a
DTLS client when parsing the Hello Verify Request message.
* The new build option MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH automatically
resizes the I/O buffers before and after handshakes, reducing the memory
consumption during application data transfer.
* Fix compilation failure when both MBEDTLS_SSL_PROTO_DTLS and
* Remove a spurious check in ssl_parse_client_psk_identity that triggered
a warning with some compilers. Fix contributed by irwir in #2856.
* Fix a function name in a debug message. Contributed by Ercan Ozturk in
* Mbed Crypto is no longer a Git submodule. The crypto part of the library
is back directly in the present repository.
* Split mbedtls_ssl_get_max_frag_len() into
mbedtls_ssl_get_output_max_frag_len() and
mbedtls_ssl_get_input_max_frag_len() to ensure that a sufficient input
buffer is allocated by the server (if MBEDTLS_SSL_VARIABLE_BUFFER_LENGTH
is defined), regardless of what MFL was configured for it.
= mbed TLS 2.21.0 branch released 2020-02-20
New deprecations
* Deprecate MBEDTLS_SSL_SRV_SUPPORT_SSLV2_CLIENT_HELLO that enables parsing
SSLv2 ClientHello messages.
* Deprecate MBEDTLS_SSL_PROTO_SSL3 that enables support for SSLv3.
* Deprecate for MBEDTLS_PKCS11_C, the wrapper around the pkcs11-helper
library which allows TLS authentication to use keys stored in a
PKCS#11 token such as a smartcard.
* Fix potential memory overread when performing an ECDSA signature
operation. The overread only happens with cryptographically low
probability (of the order of 2^-n where n is the bitsize of the curve)
unless the RNG is broken, and could result in information disclosure or
denial of service (application crash or extra resource consumption).
Found by Auke Zeilstra and Peter Schwabe, using static analysis.
* To avoid a side channel vulnerability when parsing an RSA private key,
read all the CRT parameters from the DER structure rather than
reconstructing them. Found by Alejandro Cabrera Aldaya and Billy Bob
Brumley. Reported and fix contributed by Jack Lloyd.
* The new build option MBEDTLS_SHA512_NO_SHA384 allows building SHA-512
support without SHA-384.
API changes
* Change the encoding of key types and curves in the PSA API. The new
values are aligned with the upcoming release of the PSA Crypto API
specification version 1.0.0. The main change which may break some
existing code is that elliptic curve key types no longer encode the
exact curve: a psa_ecc_curve_t or psa_key_type_t value only encodes
a curve family and the key size determines the exact curve (for example,
PSA_ECC_CURVE_SECP_R1 with 256 bits is P256R1). ARMmbed/mbed-crypto#330
* Fix an unchecked call to mbedtls_md() in the x509write module.
* Fix build failure with MBEDTLS_ZLIB_SUPPORT enabled. Reported by
Jack Lloyd in #2859. Fix submitted by jiblime in #2963.
* Fix some false-positive uninitialized variable warnings in X.509. Fix
contributed by apple-ihack-geek in #2663.
* Fix a possible error code mangling in psa_mac_verify_finish() when
a cryptographic accelerator fails. ARMmbed/mbed-crypto#345
* Fix a bug in mbedtls_pk_parse_key() that would cause it to accept some
RSA keys that would later be rejected by functions expecting private
keys. Found by Catena cyber using oss-fuzz (issue 20467).
* Fix a bug in mbedtls_pk_parse_key() that would cause it to
accept some RSA keys with invalid values by silently fixing those values.
= mbed TLS 2.20.0 branch released 2020-01-15
Default behavior changes
* The initial seeding of a CTR_DRBG instance makes a second call to the
entropy function to obtain entropy for a nonce if the entropy size is less
than 3/2 times the key size. In case you want to disable the extra call to
grab entropy, you can call mbedtls_ctr_drbg_set_nonce_len() to force the
nonce length to 0.
* Enforce that mbedtls_entropy_func() gathers a total of
MBEDTLS_ENTROPY_BLOCK_SIZE bytes or more from strong sources. In the
default configuration, on a platform with a single entropy source, the
entropy module formerly only grabbed 32 bytes, which is good enough for
security if the source is genuinely strong, but less than the expected 64
bytes (size of the entropy accumulator).
* Zeroize local variables in mbedtls_internal_aes_encrypt() and
mbedtls_internal_aes_decrypt() before exiting the function. The value of
these variables can be used to recover the last round key. To follow best
practice and to limit the impact of buffer overread vulnerabilities (like
Heartbleed) we need to zeroize them before exiting the function.
Issue reported by Tuba Yavuz, Farhaan Fowze, Ken (Yihang) Bai,
Grant Hernandez, and Kevin Butler (University of Florida) and
Dave Tian (Purdue University).
* Fix side channel vulnerability in ECDSA. Our bignum implementation is not
constant time/constant trace, so side channel attacks can retrieve the
blinded value, factor it (as it is smaller than RSA keys and not guaranteed
to have only large prime factors), and then, by brute force, recover the
key. Reported by Alejandro Cabrera Aldaya and Billy Brumley.
* Fix side channel vulnerability in ECDSA key generation. Obtaining precise
timings on the comparison in the key generation enabled the attacker to
learn leading bits of the ephemeral key used during ECDSA signatures and to
recover the private key. Reported by Jeremy Dubeuf.
* Catch failure of AES functions in mbedtls_ctr_drbg_random(). Uncaught
failures could happen with alternative implementations of AES. Bug
reported and fix proposed by Johan Uppman Bruce and Christoffer Lauri,
* Key derivation inputs in the PSA API can now either come from a key object
or from a buffer regardless of the step type.
* The CTR_DRBG module can grab a nonce from the entropy source during the
initial seeding. The default nonce length is chosen based on the key size
to achieve the security strength defined by NIST SP 800-90A. You can
change it with mbedtls_ctr_drbg_set_nonce_len().
* Add ENUMERATED tag support to the ASN.1 module. Contributed by
msopiha-linaro in ARMmbed/mbed-crypto#307.
API changes
* In the PSA API, forbid zero-length keys. To pass a zero-length input to a
key derivation function, use a buffer instead (this is now always
* Rename psa_asymmetric_sign() to psa_sign_hash() and
psa_asymmetric_verify() to psa_verify_hash().
* Fix an incorrect size in a debugging message. Reported and fix
submitted by irwir. Fixes #2717.
* Fix an unused variable warning when compiling without DTLS.
Reported and fix submitted by irwir. Fixes #2800.
* Remove a useless assignment. Reported and fix submitted by irwir.
Fixes #2801.
* Fix a buffer overflow in the PSA HMAC code when using a long key with an
unsupported algorithm. Fixes ARMmbed/mbed-crypto#254.
* Fix mbedtls_asn1_get_int to support any number of leading zeros. Credit
to OSS-Fuzz for finding a bug in an intermediate version of the fix.
* Fix mbedtls_asn1_get_bitstring_null to correctly parse bitstrings of at
most 2 bytes.
* mbedtls_ctr_drbg_set_entropy_len() and
mbedtls_hmac_drbg_set_entropy_len() now work if you call them before
mbedtls_ctr_drbg_seed() or mbedtls_hmac_drbg_seed().
* Remove the technical possibility to define custom mbedtls_md_info
structures, which was exposed only in an internal header.
* psa_close_key(0) and psa_destroy_key(0) now succeed (doing nothing, as
* Variables containing error codes are now initialized to an error code
rather than success, so that coding mistakes or memory corruption tends to
cause functions to return this error code rather than a success. There are
no known instances where this changes the behavior of the library: this is
merely a robustness improvement. ARMmbed/mbed-crypto#323
* Remove a useless call to mbedtls_ecp_group_free(). Contributed by
Alexander Krizhanovsky in ARMmbed/mbed-crypto#210.
* Speed up PBKDF2 by caching the digest calculation. Contributed by Jack
Lloyd and Fortanix Inc in ARMmbed/mbed-crypto#277.
* Small performance improvement of mbedtls_mpi_div_mpi(). Contributed by
Alexander Krizhanovsky in ARMmbed/mbed-crypto#308.
= mbed TLS 2.19.1 branch released 2019-09-16
* Declare include headers as PUBLIC to propagate to CMake project consumers
Contributed by Zachary J. Fields in PR #2949.
* Add nss_keylog to ssl_client2 and ssl_server2, enabling easier analysis of
TLS sessions with tools like Wireshark.
API Changes
* Make client_random and server_random const in
mbedtls_ssl_export_keys_ext_t, so that the key exporter is discouraged
from modifying the client/server hello.
* Fix some false-positive uninitialized variable warnings in crypto. Fix
contributed by apple-ihack-geek in #2663.
= mbed TLS 2.19.0 branch released 2019-09-06
* Fix a missing error detection in ECJPAKE. This could have caused a
predictable shared secret if a hardware accelerator failed and the other
side of the key exchange had a similar bug.
* When writing a private EC key, use a constant size for the private
value, as specified in RFC 5915. Previously, the value was written
as an ASN.1 INTEGER, which caused the size of the key to leak
about 1 bit of information on average and could cause the value to be
1 byte too large for the output buffer.
* The deterministic ECDSA calculation reused the scheme's HMAC-DRBG to
implement blinding. Because of this for the same key and message the same
blinding value was generated. This reduced the effectiveness of the
countermeasure and leaked information about the private key through side
channels. Reported by Jack Lloyd.
* Add new API functions mbedtls_ssl_session_save() and
mbedtls_ssl_session_load() to allow serializing a session, for example to
store it in non-volatile storage, and later using it for TLS session
* Add a new API function mbedtls_ssl_check_record() to allow checking that
an incoming record is valid, authentic and has not been seen before. This
feature can be used alongside Connection ID and SSL context serialisation.
The feature is enabled at compile-time by MBEDTLS_SSL_RECORD_CHECKING
* New implementation of X25519 (ECDH using Curve25519) from Project Everest
( It can be enabled at compile time
with MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED. This implementation is formally
verified and significantly faster, but is only supported on x86 platforms
(32-bit and 64-bit) using GCC, Clang or Visual Studio. Contributed by
Christoph Wintersteiger from Microsoft Research.
* Add mbedtls_net_close(), enabling the building of forking servers where
the parent process closes the client socket and continue accepting, and
the child process closes the listening socket and handles the client
socket. Contributed by Robert Larsen in #2803.
API Changes
* Add DER-encoded test CRTs to library/certs.c, allowing
the example programs ssl_server2 and ssl_client2 to be run
if MBEDTLS_FS_IO and MBEDTLS_PEM_PARSE_C are unset. Fixes #2254.
* The HAVEGE state type now uses uint32_t elements instead of int.
* The functions mbedtls_ecp_curve_list() and mbedtls_ecp_grp_id_list() now
list all curves for which at least one of ECDH or ECDSA is supported, not
just curves for which both are supported. Call mbedtls_ecdsa_can_do() or
mbedtls_ecdh_can_do() on each result to check whether each algorithm is
* The new function mbedtls_ecdsa_sign_det_ext() is similar to
mbedtls_ecdsa_sign_det() but allows passing an external RNG for the
purpose of blinding.
New deprecations
* Deprecate mbedtls_ecdsa_sign_det() in favor of a functions that can take an
RNG function as an input.
* Calling mbedtls_ecdsa_write_signature() with NULL as the f_rng argument
is now deprecated.
* Fix missing bounds checks in X.509 parsing functions that could
lead to successful parsing of ill-formed X.509 CRTs. Fixes #2437.
* Fix multiple X.509 functions previously returning ASN.1 low-level error
codes to always wrap these codes into X.509 high level error codes before
returning. Fixes #2431.
* Fix to allow building test suites with any warning that detects unused
functions. Fixes #1628.
* Fix typo in net_would_block(). Fixes #528 reported by github-monoculture.
* Remove redundant include file in timing.c. Fixes #2640 reported by irwir.
* Fix build failure when building with mingw on Windows by including
stdarg.h where needed. Fixes #2656.
* Fix Visual Studio Release x64 build configuration by inheriting
PlatformToolset from the project configuration. Fixes #1430 reported by
* Enable Suite B with subset of ECP curves. Make sure the code compiles even
if some curves are not defined. Fixes #1591 reported by dbedev.
* Fix misuse of signed arithmetic in the HAVEGE module. #2598
* Avoid use of statically sized stack buffers for certificate writing.
This previously limited the maximum size of DER encoded certificates
in mbedtls_x509write_crt_der() to 2Kb. Reported by soccerGB in #2631.
* Fix partial zeroing in x509_get_other_name. Found and fixed by ekse, #2716.
* Update test certificates that were about to expire. Reported by
Bernhard M. Wiedemann in #2357.
* Fix the build on ARMv5TE in ARM mode to not use assembly instructions
that are only available in Thumb mode. Fix contributed by Aurelien Jarno
in #2169.
* Fix propagation of restart contexts in restartable EC operations.
This could previously lead to segmentation faults in builds using an
address-sanitizer and enabling but not using MBEDTLS_ECP_RESTARTABLE.
* Fix memory leak in in mpi_miller_rabin(). Contributed by
Jens Wiklander <> in #2363
* Improve code clarity in x509_crt module, removing false-positive
uninitialized variable warnings on some recent toolchains (GCC8, etc).
Discovered and fixed by Andy Gross (Linaro), #2392.
* Fix bug in endianness conversion in bignum module. This lead to
functionally incorrect code on bigendian systems which don't have
__BYTE_ORDER__ defined. Reported by Brendan Shanks. Fixes #2622.
* Replace multiple uses of MD2 by SHA-256 in X.509 test suite. Fixes #821.
* Make it easier to define MBEDTLS_PARAM_FAILED as assert (which config.h
suggests). #2671
* Make `make clean` clean all programs always. Fixes #1862.
* Add a Dockerfile and helper scripts (,, to simplify running test suites on a Linux host. Contributed
by Peter Kolbus (Garmin).
* Add `reproducible` option to `ssl_client2` and `ssl_server2` to enable
test runs without variability. Contributed by Philippe Antoine (Catena
cyber) in #2681.
* Extended .gitignore to ignore Visual Studio artifacts. Fixed by ConfusedSushi.
* Adds fuzz targets, especially for continuous fuzzing with OSS-Fuzz.
Contributed by Philippe Antoine (Catena cyber).
* Remove the crypto part of the library from Mbed TLS. The crypto
code and tests are now only available via Mbed Crypto, which
Mbed TLS references as a Git submodule.
= mbed TLS 2.18.1 branch released 2019-07-12
* Fix build failure when building with mingw on Windows by including
stdarg.h where needed. Fixes #2656.
* Enable building of Mbed TLS as a CMake subproject. Suggested and fixed by
Ashley Duncan in #2609.
= mbed TLS 2.18.0 branch released 2019-06-11
* Add the Any Policy certificate policy oid, as defined in
rfc 5280 section
* It is now possible to use NIST key wrap mode via the mbedtls_cipher API.
Contributed by Jack Lloyd and Fortanix Inc.
* Add the Wi-SUN Field Area Network (FAN) device extended key usage.
* Add the oid certificate policy x509 extension.
* It is now possible to perform RSA PKCS v1.5 signatures with RIPEMD-160 digest.
Contributed by Jack Lloyd and Fortanix Inc.
* Extend the MBEDTLS_SSL_EXPORT_KEYS to export the handshake randbytes,
and the used tls-prf.
* Add public API for tls-prf function, according to requested enum.
* Add support for parsing otherName entries in the Subject Alternative Name
X.509 certificate extension, specifically type hardware module name,
as defined in RFC 4108 section 5.
* Add support for parsing certificate policies extension, as defined in
RFC 5280 section Currently, only the "Any Policy" policy is
* List all SAN types in the subject_alt_names field of the certificate.
Resolves #459.
* Add support for draft-05 of the Connection ID extension, as specified
The Connection ID extension allows to keep DTLS connections beyond the
lifetime of the underlying transport by adding a connection identifier
to the DTLS record header. This identifier can be used to associated an
incoming record with the correct connection data even after the peer has
changed its IP or port. The feature is enabled at compile-time by setting
MBEDTLS_SSL_DTLS_CONNECTION_ID (disabled by default), and at run-time
through the new APIs mbedtls_ssl_conf_cid() and mbedtls_ssl_set_cid().
API Changes
* Extend the MBEDTLS_SSL_EXPORT_KEYS to export the handshake randbytes,
and the used tls-prf.
* Add public API for tls-prf function, according to requested enum.
* Fix private key DER output in the key_app_writer example. File contents
were shifted by one byte, creating an invalid ASN.1 tag. Fixed by
Christian Walther in #2239.
* Fix potential memory leak in X.509 self test. Found and fixed by
Junhwan Park, #2106.
* Reduce stack usage of hkdf tests. Fixes #2195.
* Fix 1-byte buffer overflow in mbedtls_mpi_write_string() when
used with negative inputs. Found by Guido Vranken in #2404. Credit to
* Fix bugs in the AEAD test suite which would be exposed by ciphers which
either used both encrypt and decrypt key schedules, or which perform padding.
GCM and CCM were not affected. Fixed by Jack Lloyd.
* Fix incorrect default port number in ssl_mail_client example's usage.
Found and fixed by irwir. #2337
* Add psa_util.h to test/cpp_dummy_build to fix build_default_make_gcc_and_cxx.
Fixed by Peter Kolbus (Garmin). #2579
* Add missing parentheses around parameters in the definition of the
public macro MBEDTLS_X509_ID_FLAG. This could lead to invalid evaluation
in case operators binding less strongly than subtraction were used
for the parameter.
* Add a check for MBEDTLS_X509_CRL_PARSE_C in ssl_server2, guarding the crl
sni entry parameter. Reported by inestlerode in #560.
* Set the next sequence of the subject_alt_name to NULL when deleting
sequence on failure. Found and fix suggested by Philippe Antoine.
Credit to OSS-Fuzz.
* Server's RSA certificate in certs.c was SHA-1 signed. In the default
mbedTLS configuration only SHA-2 signed certificates are accepted.
This certificate is used in the demo server programs, which lead the
client programs to fail at the peer's certificate verification
due to an unacceptable hash signature. The certificate has been
updated to one that is SHA-256 signed. Fix contributed by
Illya Gerasymchuk.
* Return from various debugging routines immediately if the
provided SSL context is unset.
* Remove dead code from bignum.c in the default configuration.
Found by Coverity, reported and fixed by Peter Kolbus (Garmin). Fixes #2309.
* Add test for minimal value of MBEDTLS_MPI_WINDOW_SIZE to
Contributed by Peter Kolbus (Garmin).
* Change wording in the `mbedtls_ssl_conf_max_frag_len()`'s documentation to
improve clarity. Fixes #2258.
= mbed TLS 2.17.0 branch released 2019-03-19
* Add a new X.509 API call `mbedtls_x509_parse_der_nocopy()`
which allows copy-less parsing of DER encoded X.509 CRTs,
at the cost of additional lifetime constraints on the input
buffer, but at the benefit of reduced RAM consumption.
* Add a new function mbedtls_asn1_write_named_bitstring() to write ASN.1
named bitstring in DER as required by RFC 5280 Appendix B.
* Add MBEDTLS_REMOVE_3DES_CIPHERSUITES to allow removing 3DES ciphersuites
from the default list (enabled by default). See
API Changes
* Add a new X.509 API call `mbedtls_x509_parse_der_nocopy()`.
See the Features section for more information.
* Allow to opt in to the removal the API mbedtls_ssl_get_peer_cert()
for the benefit of saving RAM, by disabling the new compile-time
option MBEDTLS_SSL_KEEP_PEER_CERTIFICATE (enabled by default for
API stability). Disabling this option makes mbedtls_ssl_get_peer_cert()
always return NULL, and removes the peer_cert field from the
mbedtls_ssl_session structure which otherwise stores the peer's
* Make mbedtls_ecdh_get_params return an error if the second key
belongs to a different group from the first. Before, if an application
passed keys that belonged to different group, the first key's data was
interpreted according to the second group, which could lead to either
an error or a meaningless output from mbedtls_ecdh_get_params. In the
latter case, this could expose at most 5 bits of the private key.
* Fix a compilation issue with mbedtls_ecp_restart_ctx not being defined
when MBEDTLS_ECP_ALT is defined. Reported by jwhui. Fixes #2242.
* Run the AD too long test only if MBEDTLS_CCM_ALT is not defined.
Raised as a comment in #1996.
* Reduce the stack consumption of mbedtls_mpi_fill_random() which could
previously lead to a stack overflow on constrained targets.
* Add `MBEDTLS_SELF_TEST` for the mbedtls_self_test functions
in the header files, which missed the precompilation check. #971
* Fix returning the value 1 when mbedtls_ecdsa_genkey failed.
* Remove a duplicate #include in a sample program. Fixed by Masashi Honma #2326.
* Remove the mbedtls namespacing from the header file, to fix a "file not found"
build error. Fixed by Haijun Gu #2319.
* Fix signed-to-unsigned integer conversion warning
in X.509 module. Fixes #2212.
* Reduce stack usage of `mpi_write_hlp()` by eliminating recursion.
Fixes #2190.
* Fix false failure in when backup files exist in include/mbedtls
(e.g. config.h.bak). Fixed by Peter Kolbus (Garmin) #2407.
* Ensure that unused bits are zero when writing ASN.1 bitstrings when using
* Fix issue when writing the named bitstrings in KeyUsage and NsCertType
extensions in CSRs and CRTs that caused these bitstrings to not be encoded
correctly as trailing zeroes were not accounted for as unused bits in the
leading content octet. Fixes #1610.
* Reduce RAM consumption during session renegotiation by not storing
the peer CRT chain and session ticket twice.
* Include configuration file in all header files that use configuration,
instead of relying on other header files that they include.
Inserted as an enhancement for #1371
* Add support for alternative CSR headers, as used by Microsoft and defined
in RFC 7468. Found by Michael Ernst. Fixes #767.
* Correct many misspellings. Fixed by MisterDA #2371.
* Provide an abstraction of vsnprintf to allow alternative implementations
for platforms that don't provide it. Based on contributions by Joris Aerts
and Nathaniel Wesley Filardo.
* Fix clobber list in MIPS assembly for large integer multiplication.
Previously, this could lead to functionally incorrect assembly being
produced by some optimizing compilers, showing up as failures in
e.g. RSA or ECC signature operations. Reported in #1722, fix suggested
by Aurelien Jarno and submitted by Jeffrey Martin.
* Reduce the complexity of the timing tests. They were assuming more than the
underlying OS actually guarantees.
* Fix configuration queries in ssl-opt.h. #2030
* Ensure that ssl-opt.h can be run in OS X. #2029
* Re-enable certain interoperability tests in which had previously
been disabled for lack of a sufficiently recent version of GnuTLS on the CI.
* Ciphersuites based on 3DES now have the lowest priority by default when
they are enabled.
= mbed TLS 2.16.0 branch released 2018-12-21
* Add a new config.h option of MBEDTLS_CHECK_PARAMS that enables validation
of parameters in the API. This allows detection of obvious misuses of the
API, such as passing NULL pointers. The API of existing functions hasn't
changed, but requirements on parameters have been made more explicit in
the documentation. See the corresponding API documentation for each
function to see for which parameter values it is defined. This feature is
disabled by default. See its API documentation in config.h for additional
steps you have to take when enabling it.
API Changes
* The following functions in the random generator modules have been
deprecated and replaced as shown below. The new functions change
the return type from void to int to allow returning error codes when
using MBEDTLS_<MODULE>_ALT for the underlying AES or message digest
primitive. Fixes #1798.
mbedtls_ctr_drbg_update() -> mbedtls_ctr_drbg_update_ret()
mbedtls_hmac_drbg_update() -> mbedtls_hmac_drbg_update_ret()
* Extend ECDH interface to enable alternative implementations.
* Deprecate error codes of the form MBEDTLS_ERR_xxx_INVALID_KEY_LENGTH for
ARIA, CAMELLIA and Blowfish. These error codes will be replaced by
the more generic per-module error codes MBEDTLS_ERR_xxx_BAD_INPUT_DATA.
* Additional parameter validation checks have been added for the following
ECJPAKE, SHA, Chacha20 and Poly1305, cipher, pk, RSA, and MPI.
Where modules have had parameter validation added, existing parameter
checks may have changed. Some modules, such as Chacha20 had existing
parameter validation whereas other modules had little. This has now been
changed so that the same level of validation is present in all modules, and
that it is now optional with the MBEDTLS_CHECK_PARAMS flag which by default
is off. That means that checks which were previously present by default
will no longer be.
New deprecations
* Deprecate mbedtls_ctr_drbg_update and mbedtls_hmac_drbg_update
in favor of functions that can return an error code.
* Fix for Clang, which was reporting a warning for the bignum.c inline
assembly for AMD64 targets creating string literals greater than those
permitted by the ISO C99 standard. Found by Aaron Jones. Fixes #482.
* Fix runtime error in `mbedtls_platform_entropy_poll()` when run
through qemu user emulation. Reported and fix suggested by randombit
in #1212. Fixes #1212.
* Fix an unsafe bounds check when restoring an SSL session from a ticket.
This could lead to a buffer overflow, but only in case ticket authentication
was broken. Reported and fix suggested by Guido Vranken in #659.
* Add explicit integer to enumeration type casts to example program
programs/pkey/gen_key which previously led to compilation failure
on some toolchains. Reported by phoenixmcallister. Fixes #2170.
* Fix double initialization of ECC hardware that made some accelerators
* Clarify documentation of mbedtls_ssl_set_own_cert() regarding the absence
of check for certificate/key matching. Reported by Attila Molnar, #507.
= mbed TLS 2.15.1 branch released 2018-11-30
* Update the Mbed Crypto submodule to version 0.1.0b2.
= mbed TLS 2.15.0 branch released 2018-11-23
* Add an experimental build option, USE_CRYPTO_SUBMODULE, to enable use of
Mbed Crypto as the source of the cryptography implementation.
* Add an experimental configuration option, MBEDTLS_PSA_CRYPTO_C, to enable
the PSA Crypto API from Mbed Crypto when additionally used with the
* Add unit tests for AES-GCM when called through mbedtls_cipher_auth_xxx()
from the cipher abstraction layer. Fixes #2198.
= mbed TLS 2.14.1 branch released 2018-11-30
* Fix timing variations and memory access variations in RSA PKCS#1 v1.5
decryption that could lead to a Bleichenbacher-style padding oracle
attack. In TLS, this affects servers that accept ciphersuites based on
RSA decryption (i.e. ciphersuites whose name contains RSA but not
(EC)DH(E)). Discovered by Eyal Ronen (Weizmann Institute), Robert Gillham
(University of Adelaide), Daniel Genkin (University of Michigan),
Adi Shamir (Weizmann Institute), David Wong (NCC Group), and Yuval Yarom
(University of Adelaide, Data61). The attack is described in more detail
in the paper available here: CVE-2018-19608
* In mbedtls_mpi_write_binary(), don't leak the exact size of the number
via branching and memory access patterns. An attacker who could submit
a plaintext for RSA PKCS#1 v1.5 decryption but only observe the timing
of the decryption and not its result could nonetheless decrypt RSA
plaintexts and forge RSA signatures. Other asymmetric algorithms may
have been similarly vulnerable. Reported by Eyal Ronen, Robert Gillham,
Daniel Genkin, Adi Shamir, David Wong and Yuval Yarom.
* Wipe sensitive buffers on the stack in the CTR_DRBG and HMAC_DRBG
API Changes
* The new functions mbedtls_ctr_drbg_update_ret() and
mbedtls_hmac_drbg_update_ret() are similar to mbedtls_ctr_drbg_update()
and mbedtls_hmac_drbg_update() respectively, but the new functions
report errors whereas the old functions return void. We recommend that
applications use the new functions.
= mbed TLS 2.14.0 branch released 2018-11-19
* Fix overly strict DN comparison when looking for CRLs belonging to a
particular CA. This previously led to ignoring CRLs when the CRL's issuer
name and the CA's subject name differed in their string encoding (e.g.,
one using PrintableString and the other UTF8String) or in the choice of
upper and lower case. Reported by Henrik Andersson of Bosch GmbH in issue
* Fix a flawed bounds check in server PSK hint parsing. In case the
incoming message buffer was placed within the first 64KiB of address
space and a PSK-(EC)DHE ciphersuite was used, this allowed an attacker
to trigger a memory access up to 64KiB beyond the incoming message buffer,
potentially leading to an application crash or information disclosure.
* Fix mbedtls_mpi_is_prime() to use more rounds of probabilistic testing. The
previous settings for the number of rounds made it practical for an
adversary to construct non-primes that would be erroneously accepted as
primes with high probability. This does not have an impact on the
security of TLS, but can matter in other contexts with numbers chosen
potentially by an adversary that should be prime and can be validated.
For example, the number of rounds was enough to securely generate RSA key
pairs or Diffie-Hellman parameters, but was insufficient to validate
Diffie-Hellman parameters properly.
See "Prime and Prejudice" by by Martin R. Albrecht and Jake Massimo and
Kenneth G. Paterson and Juraj Somorovsky.
* Add support for temporarily suspending expensive ECC computations after
some configurable amount of operations. This is intended to be used in
constrained, single-threaded systems where ECC is time consuming and can
block other operations until they complete. This is disabled by default,
but can be enabled by MBEDTLS_ECP_RESTARTABLE at compile time and
configured by mbedtls_ecp_set_max_ops() at runtime. It applies to the new
xxx_restartable functions in ECP, ECDSA, PK and X.509 (CRL not supported
yet), and to existing functions in ECDH and SSL (currently only
implemented client-side, for ECDHE-ECDSA ciphersuites in TLS 1.2,
including client authentication).
* Add support for Arm CPU DSP extensions to accelerate asymmetric key
operations. On CPUs where the extensions are available, they can accelerate
MPI multiplications used in ECC and RSA cryptography. Contributed by
Aurelien Jarno.
* Extend RSASSA-PSS signature to allow a smaller salt size. Previously, PSS
signature always used a salt with the same length as the hash, and returned
an error if this was not possible. Now the salt size may be up to two bytes
shorter. This allows the library to support all hash and signature sizes
that comply with FIPS 186-4, including SHA-512 with a 1024-bit key.
* Add support for 128-bit keys in CTR_DRBG. Note that using keys shorter
than 256 bits limits the security of generated material to 128 bits.
API Changes
* Add a common error code of `MBEDTLS_ERR_PLATFORM_FEATURE_UNSUPPORTED` for
a feature that is not supported by underlying alternative
implementations implementing cryptographic primitives. This is useful for
hardware accelerators that don't implement all options or features.
New deprecations
* All module specific errors following the form
MBEDTLS_ERR_XXX_FEATURE_UNAVAILABLE that indicate a feature is not
supported are deprecated and are now replaced by the new equivalent
platform error.
* All module specific generic hardware acceleration errors following the
form MBEDTLS_ERR_XXX_HW_ACCEL_FAILED that are deprecated and are replaced
by the equivalent plaform error.
* Deprecate the function mbedtls_mpi_is_prime() in favor of
mbedtls_mpi_is_prime_ext() which allows specifying the number of
Miller-Rabin rounds.
* Fix wrong order of freeing in programs/ssl/ssl_server2 example
application leading to a memory leak in case both
Fixes #2069.
* Fix a bug in the update function for SSL ticket keys which previously
invalidated keys of a lifetime of less than a 1s. Fixes #1968.
* Fix failure in hmac_drbg in the benchmark sample application, when
MBEDTLS_THREADING_C is defined. Found by TrinityTonic, #1095
* Fix a bug in the record decryption routine ssl_decrypt_buf()
which lead to accepting properly authenticated but improperly
padded records in case of CBC ciphersuites using Encrypt-then-MAC.
* Fix memory leak and freeing without initialization in the example
program programs/x509/cert_write. Fixes #1422.
* Ignore IV in mbedtls_cipher_set_iv() when the cipher mode is
MBEDTLS_MODE_ECB. Found by ezdevelop. Fixes #1091.
* Zeroize memory used for buffering or reassembling handshake messages
after use.
* Use `mbedtls_platform_zeroize()` instead of `memset()` for zeroization
of sensitive data in the example programs aescrypt2 and crypt_and_hash.
* Change the default string format used for various X.509 DN attributes to
UTF8String. Previously, the use of the PrintableString format led to
wildcards and non-ASCII characters being unusable in some DN attributes.
Reported by raprepo in #1860 and by kevinpt in #468. Fix contributed by
* Fix compilation failure for configurations which use compile time
replacements of standard calloc/free functions through the macros
Reported by ole-de and ddhome2006. Fixes #882, #1642 and #1706.
* Removed support for Yotta as a build tool.
* Add tests for session resumption in DTLS.
* Close a test gap in (D)TLS between the client side and the server side:
test the handling of large packets and small packets on the client side
in the same way as on the server side.
* Change the dtls_client and dtls_server samples to work by default over
IPv6 and optionally by a build option over IPv4.
* Change the use of Windows threading to use Microsoft Visual C++ runtime
calls, rather than Win32 API calls directly. This is necessary to avoid
conflict with C runtime usage. Found and fixed by irwir.
* Remember the string format of X.509 DN attributes when replicating
X.509 DNs. Previously, DN attributes were always written in their default
string format (mostly PrintableString), which could lead to CRTs being
created which used PrintableStrings in the issuer field even though the
signing CA used UTF8Strings in its subject field; while X.509 compliant,
such CRTs were rejected in some applications, e.g. some versions of
Firefox, curl and GnuTLS. Reported in #1033 by Moschn. Fix contributed by
* Improve documentation of mbedtls_ssl_get_verify_result().
Fixes #517 reported by github-monoculture.
* Add MBEDTLS_MPI_GEN_PRIME_FLAG_LOW_ERR flag to mbedtls_mpi_gen_prime() and
use it to reduce error probability in RSA key generation to levels mandated
by FIPS-186-4.
= mbed TLS 2.13.1 branch released 2018-09-06
API Changes
* Extend the platform module with an abstraction mbedtls_platform_gmtime_r()
whose implementation should behave as a thread-safe version of gmtime().
This allows users to configure such an implementation at compile time when
the target system cannot be deduced automatically, by setting the option
MBEDTLS_PLATFORM_GMTIME_R_ALT. At this stage Mbed TLS is only able to
automatically select implementations for Windows and POSIX C libraries.
* Fix build failures on platforms where only gmtime() is available but
neither gmtime_r() nor gmtime_s() are present. Fixes #1907.
= mbed TLS 2.13.0 branch released 2018-08-31
* Fix an issue in the X.509 module which could lead to a buffer overread
during certificate extensions parsing. In case of receiving malformed
input (extensions length field equal to 0), an illegal read of one byte
beyond the input buffer is made. Found and analyzed by Nathan Crandall.
* Add support for fragmentation of outgoing DTLS handshake messages. This
is controlled by the maximum fragment length as set locally or negotiated
with the peer, as well as by a new per-connection MTU option, set using
* Add support for auto-adjustment of MTU to a safe value during the
handshake when flights do not get through (RFC 6347, section,
last paragraph).
* Add support for packing multiple records within a single datagram,
enabled by default.
* Add support for buffering out-of-order handshake messages in DTLS.
The maximum amount of RAM used for this can be controlled by the
compile-time constant MBEDTLS_SSL_DTLS_MAX_BUFFERING defined
in mbedtls/config.h.
API Changes
* Add function mbedtls_ssl_set_datagram_packing() to configure
the use of datagram packing (enabled by default).
* Fix a potential memory leak in mbedtls_ssl_setup() function. An allocation
failure in the function could lead to other buffers being leaked.
* Fixes an issue with MBEDTLS_CHACHAPOLY_C which would not compile if
MBEDTLS_ARC4_C and MBEDTLS_CIPHER_NULL_CIPHER weren't also defined. #1890
* Fix a memory leak in ecp_mul_comb() if ecp_precompute_comb() fails.
Fix contributed by Espressif Systems.
* Add ecc extensions only if an ecc based ciphersuite is used.
This improves compliance to RFC 4492, and as a result, solves
interoperability issues with BouncyCastle. Raised by milenamil in #1157.
* Replace printf with mbedtls_printf in the ARIA module. Found by
TrinityTonic in #1908.
* Fix potential use-after-free in mbedtls_ssl_get_max_frag_len()
and mbedtls_ssl_get_record_expansion() after a session reset. Fixes #1941.
* Fix a bug that caused SSL/TLS clients to incorrectly abort the handshake
with TLS versions 1.1 and earlier when the server requested authentication
without providing a list of CAs. This was due to an overly strict bounds
check in parsing the CertificateRequest message,
introduced in Mbed TLS 2.12.0. Fixes #1954.
* Fix a miscalculation of the maximum record expansion in
mbedtls_ssl_get_record_expansion() in case of ChachaPoly ciphersuites,
or CBC ciphersuites in (D)TLS versions 1.1 or higher. Fixes #1913, #1914.
* Fix undefined shifts with negative values in certificates parsing
(found by Catena cyber using oss-fuzz)
* Fix memory leak and free without initialization in pk_encrypt
and pk_decrypt example programs. Reported by Brace Stout. Fixes #1128.
* Remove redundant else statement. Raised by irwir. Fixes #1776.
* Copy headers preserving timestamps when doing a "make install".
Contributed by xueruini.
* Allow the forward declaration of public structs. Contributed by Dawid
Drozd. Fixes #1215 raised by randombit.
* Improve compatibility with some alternative CCM implementations by using
CCM test vectors from RAM.
* Add support for buffering of out-of-order handshake messages.
* Add warnings to the documentation of the HKDF module to reduce the risk
of misusing the mbedtls_hkdf_extract() and mbedtls_hkdf_expand()
functions. Fixes #1775. Reported by Brian J. Murray.
= mbed TLS 2.12.0 branch released 2018-07-25
* Fix a vulnerability in TLS ciphersuites based on CBC and using SHA-384,
in (D)TLS 1.0 to 1.2, that allowed an active network attacker to
partially recover the plaintext of messages under some conditions by
exploiting timing measurements. With DTLS, the attacker could perform
this recovery by sending many messages in the same connection. With TLS
or if mbedtls_ssl_conf_dtls_badmac_limit() was used, the attack only
worked if the same secret (for example a HTTP Cookie) has been repeatedly
sent over connections manipulated by the attacker. Connections using GCM
or CCM instead of CBC, using hash sizes other than SHA-384, or using
Encrypt-then-Mac (RFC 7366) were not affected. The vulnerability was
caused by a miscalculation (for SHA-384) in a countermeasure to the
original Lucky 13 attack. Found by Kenny Paterson, Eyal Ronen and Adi
* Fix a vulnerability in TLS ciphersuites based on CBC, in (D)TLS 1.0 to
1.2, that allowed a local attacker, able to execute code on the local
machine as well as manipulate network packets, to partially recover the
plaintext of messages under some conditions by using a cache attack
targeting an internal MD/SHA buffer. With TLS or if
mbedtls_ssl_conf_dtls_badmac_limit() was used, the attack only worked if
the same secret (for example a HTTP Cookie) has been repeatedly sent over
connections manipulated by the attacker. Connections using GCM or CCM
instead of CBC or using Encrypt-then-Mac (RFC 7366) were not affected.
Found by Kenny Paterson, Eyal Ronen and Adi Shamir.
* Add a counter-measure against a vulnerability in TLS ciphersuites based
on CBC, in (D)TLS 1.0 to 1.2, that allowed a local attacker, able to
execute code on the local machine as well as manipulate network packets,
to partially recover the plaintext of messages under some conditions (see
previous entry) by using a cache attack targeting the SSL input record
buffer. Connections using GCM or CCM instead of CBC or using
Encrypt-then-Mac (RFC 7366) were not affected. Found by Kenny Paterson,
Eyal Ronen and Adi Shamir.
* Add new crypto primitives from RFC 7539: stream cipher Chacha20, one-time
authenticator Poly1305 and AEAD construct Chacha20-Poly1305. Contributed
by Daniel King.
* Add support for CHACHA20-POLY1305 ciphersuites from RFC 7905.
* Add platform support for the Haiku OS. (
Contributed by Augustin Cavalier.
* Make the receive and transmit buffers independent sizes, for situations
where the outgoing buffer can be fixed at a smaller size than the incoming
buffer, which can save some RAM. If buffer lengths are kept equal, there
is no functional difference. Contributed by Angus Gratton, and also
independently contributed again by Paul Sokolovsky.
* Add support for key wrapping modes based on AES as defined by
NIST SP 800-38F algorithms KW and KWP and by RFC 3394 and RFC 5649.
* Fix the key_app_writer example which was writing a leading zero byte which
was creating an invalid ASN.1 tag. Found by Aryeh R. Fixes #1257.
* Fix compilation error on C++, because of a variable named new.
Found and fixed by Hirotaka Niisato in #1783.
* Fix "no symbols" warning issued by ranlib when building on Mac OS X. Fix
contributed by tabascoeye.
* Clarify documentation for mbedtls_ssl_write() to include 0 as a valid
return value. Found by @davidwu2000. #839
* Fix a memory leak in mbedtls_x509_csr_parse(), found by catenacyber,
Philippe Antoine. Fixes #1623.
* Remove unused headers included in x509.c. Found by Chris Hanson and fixed
by Brendan Shanks. Part of a fix for #992.
* Fix compilation error when MBEDTLS_ARC4_C is disabled and
MBEDTLS_CIPHER_NULL_CIPHER is enabled. Found by TrinityTonic in #1719.
* Added length checks to some TLS parsing functions. Found and fixed by
Philippe Antoine from Catena cyber. #1663.
* Fix the inline assembly for the MPI multiply helper function for i386 and
i386 with SSE2. Found by László Langó. Fixes #1550
* Fix namespacing in header files. Remove the `mbedtls` namespacing in
the `#include` in the header files. Resolves #857
* Fix compiler warning of 'use before initialisation' in
mbedtls_pk_parse_key(). Found by Martin Boye Petersen and fixed by Dawid
Drozd. #1098
* Fix decryption for zero length messages (which contain all padding) when a
CBC based ciphersuite is used together with Encrypt-then-MAC. Previously,
such a message was wrongly reported as an invalid record and therefore lead
to the connection being terminated. Seen most often with OpenSSL using
TLS 1.0. Reported by @kFYatek and by Conor Murphy on the forum. Fix
contributed by Espressif Systems. Fixes #1632
* Fix ssl_client2 example to send application data with 0-length content
when the request_size argument is set to 0 as stated in the documentation.
Fixes #1833.
* Correct the documentation for `mbedtls_ssl_get_session()`. This API has
deep copy of the session, and the peer certificate is not lost. Fixes #926.
* Fix build using -std=c99. Fixed by Nick Wilson.
* Fail when receiving a TLS alert message with an invalid length, or invalid
zero-length messages when using TLS 1.2. Contributed by Espressif Systems.
* Change the default behaviour of mbedtls_hkdf_extract() to return an error
when calling with a NULL salt and non-zero salt_len. Contributed by
Brian J Murray
* Change the shebang line in Perl scripts to look up perl in the PATH.
Contributed by fbrosson.
* Allow overriding the time on Windows via the platform-time abstraction.
Fixed by Nick Wilson.
* Use gmtime_r/gmtime_s for thread-safety. Fixed by Nick Wilson.
= mbed TLS 2.11.0 branch released 2018-06-18
* Add additional block mode, OFB (Output Feedback), to the AES module and
cipher abstraction module.
* Implement the HMAC-based extract-and-expand key derivation function
(HKDF) per RFC 5869. Contributed by Thomas Fossati.
* Add support for the CCM* block cipher mode as defined in IEEE Std. 802.15.4.
* Add support for the XTS block cipher mode with AES (AES-XTS).
Contributed by Aorimn in pull request #414.
* In TLS servers, support offloading private key operations to an external
cryptoprocessor. Private key operations can be asynchronous to allow
non-blocking operation of the TLS server stack.
* Fix the cert_write example to handle certificates signed with elliptic
curves as well as RSA. Fixes #777 found by dbedev.
* Fix for redefinition of _WIN32_WINNT to avoid overriding a definition
used by user applications. Found and fixed by Fabio Alessandrelli.
* Fix compilation warnings with IAR toolchain, on 32 bit platform.
Reported by rahmanih in #683
* Fix braces in mbedtls_memory_buffer_alloc_status(). Found by sbranden, #552.
* Changed CMake defaults for IAR to treat all compiler warnings as errors.
* Changed the Clang parameters used in the CMake build files to work for
versions later than 3.6. Versions of Clang earlier than this may no longer
work. Fixes #1072
= mbed TLS 2.10.0 branch released 2018-06-06
* Add support for ARIA cipher (RFC 5794) and associated TLS ciphersuites
(RFC 6209). Disabled by default, see MBEDTLS_ARIA_C in config.h
API Changes
* Extend the platform module with a util component that contains
functionality shared by multiple Mbed TLS modules. At this stage
platform_util.h (and its associated platform_util.c) only contain
mbedtls_platform_zeroize(), which is a critical function from a security
point of view. mbedtls_platform_zeroize() needs to be regularly tested
against compilers to ensure that calls to it are not removed from the
output binary as part of redundant code elimination optimizations.
Therefore, mbedtls_platform_zeroize() is moved to the platform module to
facilitate testing and maintenance.
* Fix an issue with MicroBlaze support in bn_mul.h which was causing the
build to fail. Found by zv-io. Fixes #1651.
* Support TLS testing in out-of-source builds using cmake. Fixes #1193.
* Fix redundant declaration of mbedtls_ssl_list_ciphersuites. Raised by
TrinityTonic. #1359.
= mbed TLS 2.9.0 branch released 2018-04-30
* Fix an issue in the X.509 module which could lead to a buffer overread
during certificate validation. Additionally, the issue could also lead to
unnecessary callback checks being made or to some validation checks to be
omitted. The overread could be triggered remotely, while the other issues
would require a non DER-compliant certificate to be correctly signed by a
trusted CA, or a trusted CA with a non DER-compliant certificate. Found by
luocm. Fixes #825.
* Fix the buffer length assertion in the ssl_parse_certificate_request()
function which led to an arbitrary overread of the message buffer. The
overreads could be caused by receiving a malformed message at the point
where an optional signature algorithms list is expected when the signature
algorithms section is too short. In builds with debug output, the overread
data is output with the debug data.
* Fix a client-side bug in the validation of the server's ciphersuite choice
which could potentially lead to the client accepting a ciphersuite it didn't
offer or a ciphersuite that cannot be used with the TLS or DTLS version
chosen by the server. This could lead to corruption of internal data
structures for some configurations.
* Add an option, MBEDTLS_AES_FEWER_TABLES, to dynamically compute smaller AES
tables during runtime, thereby reducing the RAM/ROM footprint by ~6KiB.
Suggested and contributed by jkivilin in pull request #394.
* Add initial support for Curve448 (RFC 7748). Only mbedtls_ecp_mul() and
ECDH primitive functions (mbedtls_ecdh_gen_public(),
mbedtls_ecdh_compute_shared()) are supported for now. Contributed by
Nicholas Wilson in pull request #348.
API Changes
* Extend the public API with the function of mbedtls_net_poll() to allow user
applications to wait for a network context to become ready before reading
or writing.
* Add function mbedtls_ssl_check_pending() to the public API to allow
a check for whether more more data is pending to be processed in the
internal message buffers.
This function is necessary to determine when it is safe to idle on the
underlying transport in case event-driven IO is used.
* Fix a spurious uninitialized variable warning in cmac.c. Fix independently
contributed by Brian J Murray and David Brown.
* Add missing dependencies in test suites that led to build failures
in configurations that omit certain hashes or public-key algorithms.
Fixes #1040.
* Fix C89 incompatibility in benchmark.c. Contributed by Brendan Shanks.
* Add missing dependencies for MBEDTLS_HAVE_TIME_DATE and
MBEDTLS_VERSION_FEATURES in some test suites. Contributed by
Deomid Ryabkov. Fixes #1299, #1475.
* Fix the Makefile build process for building shared libraries on Mac OS X.
Fixed by mnacamura.
* Fix parsing of PKCS#8 encoded Elliptic Curve keys. Previously Mbed TLS was
unable to parse keys which had only the optional parameters field of the
ECPrivateKey structure. Found by Jethro Beekman, fixed in #1379.
* Return the plaintext data more quickly on unpadded CBC decryption, as
stated in the mbedtls_cipher_update() documentation. Contributed by
Andy Leiserson.
* Fix overriding and ignoring return values when parsing and writing to
a file in pk_sign program. Found by kevlut in #1142.
* Restrict usage of error code MBEDTLS_ERR_SSL_WANT_READ to situations
where data needs to be fetched from the underlying transport in order
to make progress. Previously, this error code was also occasionally
returned when unexpected messages were being discarded, ignoring that
further messages could potentially already be pending to be processed
in the internal buffers; these cases led to deadlocks when event-driven
I/O was used. Found and reported by Hubert Mis in #772.
* Fix buffer length assertions in the ssl_parse_certificate_request()
function which leads to a potential one byte overread of the message
* Fix invalid buffer sizes passed to zlib during record compression and
* Fix the soversion of libmbedcrypto to match the soversion of the
maintained 2.7 branch. The soversion was increased in Mbed TLS
version 2.7.1 to reflect breaking changes in that release, but the
increment was missed in 2.8.0 and later releases outside of the 2.7 branch.
* Remove some redundant code in bignum.c. Contributed by Alexey Skalozub.
* Support cmake builds where Mbed TLS is a subproject. Fix contributed
independently by Matthieu Volat and Arne Schwabe.
* Improve testing in configurations that omit certain hashes or
public-key algorithms. Includes contributions by Gert van Dijk.
* Improve negative testing of X.509 parsing.
* Do not define global mutexes around readdir() and gmtime() in
configurations where the feature is disabled. Found and fixed by Gergely
* Harden the function mbedtls_ssl_config_free() against misuse, so that it
doesn't leak memory if the user doesn't use mbedtls_ssl_conf_psk() and
instead incorrectly manipulates the configuration structure directly.
Found and fix submitted by junyeonLEE in #1220.
* Provide an empty implementation of mbedtls_pkcs5_pbes2() when
MBEDTLS_ASN1_PARSE_C is not enabled. This allows the use of PBKDF2
without PBES2. Fixed by Marcos Del Sol Vives.
* Add the order of the base point as N in the mbedtls_ecp_group structure
for Curve25519 (other curves had it already). Contributed by Nicholas
Wilson #481
* Improve the documentation of mbedtls_net_accept(). Contributed by Ivan
* Improve the documentation of mbedtls_ssl_write(). Suggested by
Paul Sokolovsky in #1356.
* Add an option in the Makefile to support ar utilities where the operation
letter must not be prefixed by '-', such as LLVM. Found and fixed by
Alex Hixon.
* Allow configuring the shared library extension by setting the DLEXT
environment variable when using the project makefiles.
* Optimize unnecessary zeroing in mbedtls_mpi_copy. Based on a contribution
by Alexey Skalozub in #405.
* In the SSL module, when f_send, f_recv or f_recv_timeout report
transmitting more than the required length, return an error. Raised by
Sam O'Connor in #1245.
* Improve robustness of mbedtls_ssl_derive_keys against the use of
HMAC functions with non-HMAC ciphersuites. Independently contributed
by Jiayuan Chen in #1377. Fixes #1437.
* Improve security of RSA key generation by including criteria from
FIPS 186-4. Contributed by Jethro Beekman. #1380
* Declare functions in header files even when an alternative implementation
of the corresponding module is activated by defining the corresponding
MBEDTLS_XXX_ALT macro. This means that alternative implementations do
not need to copy the declarations, and ensures that they will have the
same API.
* Add platform setup and teardown calls in test suites.
= mbed TLS 2.8.0 branch released 2018-03-16
Default behavior changes
* The truncated HMAC extension now conforms to RFC 6066. This means
that when both sides of a TLS connection negotiate the truncated
HMAC extension, Mbed TLS can now interoperate with other
compliant implementations, but this breaks interoperability with
prior versions of Mbed TLS. To restore the old behavior, enable
the (deprecated) option MBEDTLS_SSL_TRUNCATED_HMAC_COMPAT in
config.h. Found by Andreas Walz (ivESK, Offenburg University of
Applied Sciences).
* Fix implementation of the truncated HMAC extension. The previous
implementation allowed an offline 2^80 brute force attack on the
HMAC key of a single, uninterrupted connection (with no
resumption of the session).
* Verify results of RSA private key operations to defend
against Bellcore glitch attack.
* Fix a buffer overread in ssl_parse_server_key_exchange() that could cause
a crash on invalid input.
* Fix a buffer overread in ssl_parse_server_psk_hint() that could cause a
crash on invalid input.
* Fix CRL parsing to reject CRLs containing unsupported critical
extensions. Found by Falko Strenzke and Evangelos Karatsiolis.
* Extend PKCS#8 interface by introducing support for the entire SHA
algorithms family when encrypting private keys using PKCS#5 v2.0.
This allows reading encrypted PEM files produced by software that
uses PBKDF2-SHA2, such as OpenSSL 1.1. Submitted by Antonio Quartulli,
OpenVPN Inc. Fixes #1339
* Add support for public keys encoded in PKCS#1 format. #1122
New deprecations
* Deprecate support for record compression (configuration option
* Fix the name of a DHE parameter that was accidentally changed in 2.7.0.
Fixes #1358.
* Fix test_suite_pk to work on 64-bit ILP32 systems. #849
* Fix mbedtls_x509_crt_profile_suiteb, which used to reject all certificates
with flag MBEDTLS_X509_BADCERT_BAD_PK even when the key type was correct.
In the context of SSL, this resulted in handshake failure. Reported by
daniel in the Mbed TLS forum. #1351
* Fix Windows x64 builds with the included mbedTLS.sln file. #1347
* Fix setting version TLSv1 as minimal version, even if TLS 1
* Fix compilation error on Mingw32 when _TRUNCATE is defined. Use _TRUNCATE
only if __MINGW32__ not defined. Fix suggested by Thomas Glanzmann and
Nick Wilson on issue #355
* In test_suite_pk, pass valid parameters when testing for hash length
overflow. #1179
* Fix memory allocation corner cases in memory_buffer_alloc.c module. Found
by Guido Vranken. #639
* Log correct number of ciphersuites used in Client Hello message. #918
* Fix X509 CRT parsing that would potentially accept an invalid tag when
parsing the subject alternative names.
* Fix a possible arithmetic overflow in ssl_parse_server_key_exchange()
that could cause a key exchange to fail on valid data.
* Fix a possible arithmetic overflow in ssl_parse_server_psk_hint() that
could cause a key exchange to fail on valid data.
* Don't define mbedtls_aes_decrypt and mbedtls_aes_encrypt under
* Fix a 1-byte heap buffer overflow (read-only) during private key parsing.
Found through fuzz testing.
* Fix tag lengths and value ranges in the documentation of CCM encryption.
Contributed by Mathieu Briand.
* Fix typo in a comment ctr_drbg.c. Contributed by Paul Sokolovsky.
* Remove support for the library reference configuration for picocoin.
* MD functions deprecated in 2.7.0 are no longer inline, to provide
a migration path for those depending on the library's ABI.
* Clarify the documentation of mbedtls_ssl_setup.
* Use (void) when defining functions with no parameters. Contributed by
Joris Aerts. #678
= mbed TLS 2.7.0 branch released 2018-02-03
* Fix a heap corruption issue in the implementation of the truncated HMAC
extension. When the truncated HMAC extension is enabled and CBC is used,
sending a malicious application packet could be used to selectively corrupt
6 bytes on the peer's heap, which could potentially lead to crash or remote
code execution. The issue could be triggered remotely from either side in
both TLS and DTLS. CVE-2018-0488
* Fix a buffer overflow in RSA-PSS verification when the hash was too large
for the key size, which could potentially lead to crash or remote code
execution. Found by Seth Terashima, Qualcomm Product Security Initiative,
Qualcomm Technologies Inc. CVE-2018-0487
* Fix buffer overflow in RSA-PSS verification when the unmasked data is all
* Fix an unsafe bounds check in ssl_parse_client_psk_identity() when adding
64 KiB to the address of the SSL buffer and causing a wrap around.
* Fix a potential heap buffer overflow in mbedtls_ssl_write(). When the (by
default enabled) maximum fragment length extension is disabled in the
config and the application data buffer passed to mbedtls_ssl_write
is larger than the internal message buffer (16384 bytes by default), the
latter overflows. The exploitability of this issue depends on whether the
application layer can be forced into sending such large packets. The issue
was independently reported by Tim Nordell via e-mail and by Florin Petriuc
and sjorsdewit on GitHub. Fix proposed by Florin Petriuc in #1022.
Fixes #707.
* Add a provision to prevent compiler optimizations breaking the time
constancy of mbedtls_ssl_safer_memcmp().
* Ensure that buffers are cleared after use if they contain sensitive data.
Changes were introduced in multiple places in the library.
* Set PEM buffer to zero before freeing it, to avoid decoded private keys
being leaked to memory after release.
* Fix dhm_check_range() failing to detect trivial subgroups and potentially
leaking 1 bit of the private key. Reported by prashantkspatil.
* Make mbedtls_mpi_read_binary() constant-time with respect to the input
data. Previously, trailing zero bytes were detected and omitted for the
sake of saving memory, but potentially leading to slight timing
differences. Reported by Marco Macchetti, Kudelski Group.
* Wipe stack buffer temporarily holding EC private exponent
after keypair generation.
* Fix a potential heap buffer over-read in ALPN extension parsing
(server-side). Could result in application crash, but only if an ALPN
name larger than 16 bytes had been configured on the server.
* Change default choice of DHE parameters from untrustworthy RFC 5114
to RFC 3526 containing parameters generated in a nothing-up-my-sleeve
* Allow comments in test data files.
* The selftest program can execute a subset of the tests based on command
line arguments.
* New unit tests for timing. Improve the self-test to be more robust
when run on a heavily-loaded machine.
* Add alternative implementation support for CCM and CMAC (MBEDTLS_CCM_ALT,
MBEDTLS_CMAC_ALT). Submitted by Steven Cooreman, Silicon Labs.
* Add support for alternative implementations of GCM, selected by the
configuration flag MBEDTLS_GCM_ALT.
* Add support for alternative implementations for ECDSA, controlled by new
The following functions from the ECDSA module can be replaced
with alternative implementation:
mbedtls_ecdsa_sign(), mbedtls_ecdsa_verify() and mbedtls_ecdsa_genkey().
* Add support for alternative implementation of ECDH, controlled by the
new configuration flags MBEDTLS_ECDH_COMPUTE_SHARED_ALT and
The following functions from the ECDH module can be replaced
with an alternative implementation:
mbedtls_ecdh_gen_public() and mbedtls_ecdh_compute_shared().
* Add support for alternative implementation of ECJPAKE, controlled by
the new configuration flag MBEDTLS_ECJPAKE_ALT.
* Add mechanism to provide alternative implementation of the DHM module.
API Changes
* Extend RSA interface by multiple functions allowing structure-
independent setup and export of RSA contexts. Most notably,
mbedtls_rsa_import() and mbedtls_rsa_complete() are introduced for setting
up RSA contexts from partial key material and having them completed to the
needs of the implementation automatically. This allows to setup private RSA
contexts from keys consisting of N,D,E only, even if P,Q are needed for the
purpose or CRT and/or blinding.
* The configuration option MBEDTLS_RSA_ALT can be used to define alternative
implementations of the RSA interface declared in rsa.h.
* The following functions in the message digest modules (MD2, MD4, MD5,
SHA1, SHA256, SHA512) have been deprecated and replaced as shown below.
The new functions change the return type from void to int to allow
returning error codes when using MBEDTLS_<MODULE>_ALT.
mbedtls_<MODULE>_starts() -> mbedtls_<MODULE>_starts_ret()
mbedtls_<MODULE>_update() -> mbedtls_<MODULE>_update_ret()
mbedtls_<MODULE>_finish() -> mbedtls_<MODULE>_finish_ret()
mbedtls_<MODULE>_process() -> mbedtls_internal_<MODULE>_process()
New deprecations
* Deprecate usage of RSA primitives with non-matching key-type
(e.g. signing with a public key).
* Direct manipulation of structure fields of RSA contexts is deprecated.
Users are advised to use the extended RSA API instead.
* Deprecate usage of message digest functions that return void
(mbedtls_<MODULE>_starts, mbedtls_<MODULE>_update,
mbedtls_<MODULE>_finish and mbedtls_<MODULE>_process where <MODULE> is
any of MD2, MD4, MD5, SHA1, SHA256, SHA512) in favor of functions
that can return an error code.
* Deprecate untrustworthy DHE parameters from RFC 5114. Superseded by
parameters from RFC 3526 or the newly added parameters from RFC 7919.
* Deprecate hex string DHE constants MBEDTLS_DHM_RFC3526_MODP_2048_P etc.
Supserseded by binary encoded constants MBEDTLS_DHM_RFC3526_MODP_2048_P_BIN
* Deprecate mbedtls_ssl_conf_dh_param() for setting default DHE parameters
from hex strings. Superseded by mbedtls_ssl_conf_dh_param_bin()
accepting DHM parameters in binary form, matching the new constants.
* Fix ssl_parse_record_header() to silently discard invalid DTLS records
as recommended in RFC 6347 Section
* Fix memory leak in mbedtls_ssl_set_hostname() when called multiple times.
Found by projectgus and Jethro Beekman, #836.
* Fix usage help in ssl_server2 example. Found and fixed by Bei Lin.
* Parse signature algorithm extension when renegotiating. Previously,
renegotiated handshakes would only accept signatures using SHA-1
regardless of the peer's preferences, or fail if SHA-1 was disabled.
* Fix leap year calculation in x509_date_is_valid() to ensure that invalid
dates on leap years with 100 and 400 intervals are handled correctly. Found
by Nicholas Wilson. #694
* Fix some invalid RSA-PSS signatures with keys of size 8N+1 that were
accepted. Generating these signatures required the private key.
* Fix out-of-memory problem when parsing 4096-bit PKCS8-encrypted RSA keys.
Found independently by Florian in the mbed TLS forum and by Mishamax.
#878, #1019.
* Fix variable used before assignment compilation warnings with IAR
toolchain. Found by gkerrien38.
* Fix unchecked return codes from AES, DES and 3DES functions in
pem_aes_decrypt(), pem_des_decrypt() and pem_des3_decrypt() respectively.
If a call to one of the functions of the cryptographic primitive modules
failed, the error may not be noticed by the function
mbedtls_pem_read_buffer() causing it to return invalid values. Found by
Guido Vranken. #756
* Include configuration file in md.h, to fix compilation warnings.
Reported by aaronmdjones in #1001
* Correct extraction of signature-type from PK instance in X.509 CRT and CSR
writing routines that prevented these functions to work with alternative
RSA implementations. Raised by J.B. in the Mbed TLS forum. Fixes #1011.
* Don't print X.509 version tag for v1 CRT's, and omit extensions for
non-v3 CRT's.
* Fix bugs in RSA test suite under MBEDTLS_NO_PLATFORM_ENTROPY. #1023 #1024
* Fix net_would_block() to avoid modification by errno through fcntl() call.
Found by nkolban. Fixes #845.
* Fix handling of handshake messages in mbedtls_ssl_read() in case
MBEDTLS_SSL_RENEGOTIATION is disabled. Found by erja-gp.
* Add a check for invalid private parameters in mbedtls_ecdsa_sign().
Reported by Yolan Romailler.
* Fix word size check in in pk.c to not depend on MBEDTLS_HAVE_INT64.
* Fix incorrect unit in benchmark output. #850
* Add size-checks for record and handshake message content, securing
fragile yet non-exploitable code-paths.
* Fix crash when calling mbedtls_ssl_cache_free() twice. Found by
MilenkoMitrovic, #1104
* Fix mbedtls_timing_alarm(0) on Unix and MinGW.
* Fix use of uninitialized memory in mbedtls_timing_get_timer() when reset=1.
* Fix possible memory leaks in mbedtls_gcm_self_test().
* Added missing return code checks in mbedtls_aes_self_test().
* Fix issues in RSA key generation program programs/x509/rsa_genkey and the
RSA test suite where the failure of CTR DRBG initialization lead to
freeing an RSA context and several MPI's without proper initialization
* Fix error message in programs/pkey/gen_key.c. Found and fixed by Chris Xue.
* Fix programs/pkey/dh_server.c so that it actually works with dh_client.c.
Found and fixed by Martijn de Milliano.
* Fix an issue in the cipher decryption with the mode
MBEDTLS_PADDING_ONE_AND_ZEROS that sometimes accepted invalid padding.
Note, this padding mode is not used by the TLS protocol. Found and fixed by
Micha Kraus.
* Fix the entropy.c module to not call mbedtls_sha256_starts() or
mbedtls_sha512_starts() in the mbedtls_entropy_init() function.
* Fix the entropy.c module to ensure that mbedtls_sha256_init() or
mbedtls_sha512_init() is called before operating on the relevant context
structure. Do not assume that zeroizing a context is a correct way to
reset it. Found independently by ccli8 on Github.
* In mbedtls_entropy_free(), properly free the message digest context.
* Fix status handshake status message in programs/ssl/dtls_client.c. Found
and fixed by muddog.
* Extend cert_write example program by options to set the certificate version
and the message digest. Further, allow enabling/disabling of authority
identifier, subject identifier and basic constraints extensions.
* Only check for necessary RSA structure fields in `mbedtls_rsa_private`. In
particular, don't require P,Q if neither CRT nor blinding are
used. Reported and fix proposed independently by satur9nine and sliai
on GitHub.
* Only run AES-192 self-test if AES-192 is available. Fixes #963.
* Tighten the RSA PKCS#1 v1.5 signature verification code and remove the
undeclared dependency of the RSA module on the ASN.1 module.
* Update all internal usage of deprecated message digest functions to the
new ones with return codes. In particular, this modifies the
mbedtls_md_info_t structure. Propagate errors from these functions
everywhere except some locations in the ssl_tls.c module.
* Improve CTR_DRBG error handling by propagating underlying AES errors.
* Add MBEDTLS_ERR_XXX_HW_ACCEL_FAILED error codes for all cryptography
modules where the software implementation can be replaced by a hardware
* Add explicit warnings for the use of MD2, MD4, MD5, SHA-1, DES and ARC4
throughout the library.
= mbed TLS 2.6.0 branch released 2017-08-10
* Fix authentication bypass in SSL/TLS: when authmode is set to optional,
mbedtls_ssl_get_verify_result() would incorrectly return 0 when the peer's
X.509 certificate chain had more than MBEDTLS_X509_MAX_INTERMEDIATE_CA
(default: 8) intermediates, even when it was not trusted. This could be
triggered remotely from either side. (With authmode set to 'required'
(the default), the handshake was correctly aborted).
* Reliably wipe sensitive data after use in the AES example applications
programs/aes/aescrypt2 and programs/aes/crypt_and_hash.
Found by Laurent Simon.
* Add the functions mbedtls_platform_setup() and mbedtls_platform_teardown()
and the context struct mbedtls_platform_context to perform
platform-specific setup and teardown operations. The macro
MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT allows the functions to be overridden
by the user in a platform_alt.h file. These new functions are required in
some embedded environments to provide a means of initialising underlying
cryptographic acceleration hardware.
API Changes
* Reverted API/ABI breaking changes introduced in mbed TLS 2.5.1, to make the
API consistent with mbed TLS 2.5.0. Specifically removed the inline
qualifier from the functions mbedtls_aes_decrypt, mbedtls_aes_encrypt,
mbedtls_ssl_ciphersuite_uses_ec and mbedtls_ssl_ciphersuite_uses_psk. Found
by James Cowgill. #978
* Certificate verification functions now set flags to -1 in case the full
chain was not verified due to an internal error (including in the verify
callback) or chain length limitations.
* With authmode set to optional, the TLS handshake is now aborted if the
verification of the peer's certificate failed due to an overlong chain or
a fatal error in the verify callback.
* Add a check if iv_len is zero in GCM, and return an error if it is zero.
Reported by roberto. #716
* Replace preprocessor condition from #if defined(MBEDTLS_THREADING_PTHREAD)
to #if defined(MBEDTLS_THREADING_C) as the library cannot assume they will
always be implemented by pthread support. #696
* Fix a resource leak on Windows platforms in mbedtls_x509_crt_parse_path(),
in the case of an error. Found by redplait. #590
* Add MBEDTLS_MPI_CHK to check for error value of mbedtls_mpi_fill_random.
Reported and fix suggested by guidovranken. #740
* Fix conditional preprocessor directives in bignum.h to enable 64-bit
compilation when using ARM Compiler 6.
* Fix a potential integer overflow in the version verification for DER
encoded X.509 CRLs. The overflow could enable maliciously constructed CRLs
to bypass the version verification check. Found by Peng Li/Yueh-Hsun Lin,
KNOX Security, Samsung Research America
* Fix potential integer overflow in the version verification for DER
encoded X.509 CSRs. The overflow could enable maliciously constructed CSRs
to bypass the version verification check. Found by Peng Li/Yueh-Hsun Lin,
KNOX Security, Samsung Research America
* Fix a potential integer overflow in the version verification for DER
encoded X.509 certificates. The overflow could enable maliciously
constructed certificates to bypass the certificate verification check.
* Fix a call to the libc function time() to call the platform abstraction
function mbedtls_time() instead. Found by wairua. #666
* Avoid shadowing of time and index functions through mbed TLS function
arguments. Found by inestlerode. #557.
* Added config.h option MBEDTLS_NO_UDBL_DIVISION, to prevent the use of
64-bit division. This is useful on embedded platforms where 64-bit division
created a dependency on external libraries. #708
* Removed mutexes from ECP hardware accelerator code. Now all hardware
accelerator code in the library leaves concurrency handling to the
platform. Reported by Steven Cooreman. #863
* Define the macro MBEDTLS_AES_ROM_TABLES in the configuration file
config-no-entropy.h to reduce the RAM footprint.
* Added a test script that can be hooked into git that verifies commits
before they are pushed.
* Improve documentation of PKCS1 decryption functions.
= mbed TLS 2.5.1 released 2017-06-21
* Fixed unlimited overread of heap-based buffer in mbedtls_ssl_read().
The issue could only happen client-side with renegotiation enabled.
Could result in DoS (application crash) or information leak
(if the application layer sent data read from mbedtls_ssl_read()
back to the server or to a third party). Can be triggered remotely.
* Removed SHA-1 and RIPEMD-160 from the default hash algorithms for
certificate verification. SHA-1 can be turned back on with a compile-time
option if needed.
* Fixed offset in FALLBACK_SCSV parsing that caused TLS server to fail to
detect it sometimes. Reported by Hugo Leisink. #810
* Tighten parsing of RSA PKCS#1 v1.5 signatures, to avoid a
potential Bleichenbacher/BERserk-style attack.
* Remove size zero arrays from ECJPAKE test suite. Size zero arrays are not
valid C and they prevented the test from compiling in Visual Studio 2015
and with GCC using the -Wpedantic compilation option.
* Fix insufficient support for signature-hash-algorithm extension,
resulting in compatibility problems with Chrome. Found by hfloyrd. #823
* Fix behaviour that hid the original cause of fatal alerts in some cases
when sending the alert failed. The fix makes sure not to hide the error
that triggered the alert.
* Fix SSLv3 renegotiation behaviour and stop processing data received from
peer after sending a fatal alert to refuse a renegotiation attempt.
Previous behaviour was to keep processing data even after the alert has
been sent.
* Accept empty trusted CA chain in authentication mode
MBEDTLS_SSL_VERIFY_OPTIONAL. Found by Jethro Beekman. #864
* Fix implementation of mbedtls_ssl_parse_certificate() to not annihilate
fatal errors in authentication mode MBEDTLS_SSL_VERIFY_OPTIONAL and to
reflect bad EC curves within verification result.
* Fix bug that caused the modular inversion function to accept the invalid
modulus 1 and therefore to hang. Found by blaufish. #641.
* Fix incorrect sign computation in modular exponentiation when the base is
a negative MPI. Previously the result was always negative. Found by Guido
* Fix a numerical underflow leading to stack overflow in mpi_read_file()
that was triggered uppon reading an empty line. Found by Guido Vranken.
* Send fatal alerts in more cases. The previous behaviour was to skip
sending the fatal alert and just drop the connection.
* Clarify ECDSA documentation and improve the sample code to avoid
misunderstanding and potentially dangerous use of the API. Pointed out
by Jean-Philippe Aumasson.
= mbed TLS 2.5.0 branch released 2017-05-17
* Wipe stack buffers in RSA private key operations
(rsa_rsaes_pkcs1_v15_decrypt(), rsa_rsaes_oaep_decrypt). Found by Laurent
* Add exponent blinding to RSA private operations as a countermeasure
against side-channel attacks like the cache attack described in
Found and fix proposed by Michael Schwarz, Samuel Weiser, Daniel Gruss,
Clémentine Maurice and Stefan Mangard.
* Add hardware acceleration support for the Elliptic Curve Point module.
This involved exposing parts of the internal interface to enable
replacing the core functions and adding and alternative, module level
replacement support for enabling the extension of the interface.
* Add a new configuration option to 'mbedtls_ssl_config' to enable
suppressing the CA list in Certificate Request messages. The default
behaviour has not changed, namely every configured CAs name is included.
API Changes
* The following functions in the AES module have been deprecated and replaced
by the functions shown below. The new functions change the return type from
void to int to allow returning error codes when using MBEDTLS_AES_ALT,
mbedtls_aes_decrypt() -> mbedtls_internal_aes_decrypt()
mbedtls_aes_encrypt() -> mbedtls_internal_aes_encrypt()
* Remove macros from compat-1.3.h that correspond to deleted items from most
recent versions of the library. Found by Kyle Keen.
* Fixed issue in the Threading module that prevented mutexes from
initialising. Found by sznaider. #667 #843
* Add checks in the PK module for the RSA functions on 64-bit systems.
The PK and RSA modules use different types for passing hash length and
without these checks the type cast could lead to data loss. Found by Guido
= mbed TLS 2.4.2 branch released 2017-03-08
* Add checks to prevent signature forgeries for very large messages while
using RSA through the PK module in 64-bit systems. The issue was caused by
some data loss when casting a size_t to an unsigned int value in the
functions rsa_verify_wrap(), rsa_sign_wrap(), rsa_alt_sign_wrap() and
mbedtls_pk_sign(). Found by Jean-Philippe Aumasson.
* Fixed potential livelock during the parsing of a CRL in PEM format in
mbedtls_x509_crl_parse(). A string containing a CRL followed by trailing
characters after the footer could result in the execution of an infinite
loop. The issue can be triggered remotely. Found by Greg Zaverucha,
* Removed MD5 from the allowed hash algorithms for CertificateRequest and
CertificateVerify messages, to prevent SLOTH attacks against TLS 1.2.
Introduced by interoperability fix for #513.
* Fixed a bug that caused freeing a buffer that was allocated on the stack,
when verifying the validity of a key on secp224k1. This could be
triggered remotely for example with a maliciously constructed certificate
and potentially could lead to remote code execution on some platforms.
Reported independently by rongsaws and Aleksandar Nikolic, Cisco Talos
team. #569 CVE-2017-2784
* Fix output certificate verification flags set by x509_crt_verify_top() when
traversing a chain of trusted CA. The issue would cause both flags,
set when the verification conditions are not met regardless of the cause.
Found by Harm Verhagen and inestlerode. #665 #561
* Fix the redefinition of macro ssl_set_bio to an undefined symbol
mbedtls_ssl_set_bio_timeout in compat-1.3.h, by removing it.
Found by omlib-lin. #673
* Fix unused variable/function compilation warnings in pem.c, x509_crt.c and
x509_csr.c that are reported when building mbed TLS with a config.h that
does not define MBEDTLS_PEM_PARSE_C. Found by omnium21. #562
* Fix incorrect renegotiation condition in ssl_check_ctr_renegotiate() that
would compare 64 bits of the record counter instead of 48 bits as indicated
in RFC 6347 Section 4.3.1. This could cause the execution of the
renegotiation routines at unexpected times when the protocol is DTLS. Found
by wariua. #687
* Fixed multiple buffer overreads in mbedtls_pem_read_buffer() when parsing
the input string in PEM format to extract the different components. Found
by Eyal Itkin.
* Fixed potential arithmetic overflow in mbedtls_ctr_drbg_reseed() that could
cause buffer bound checks to be bypassed. Found by Eyal Itkin.
* Fixed potential arithmetic overflows in mbedtls_cipher_update() that could
cause buffer bound checks to be bypassed. Found by Eyal Itkin.
* Fixed potential arithmetic overflow in mbedtls_md2_update() that could
cause buffer bound checks to be bypassed. Found by Eyal Itkin.
* Fixed potential arithmetic overflow in mbedtls_base64_decode() that could
cause buffer bound checks to be bypassed. Found by Eyal Itkin.
* Fixed heap overreads in mbedtls_x509_get_time(). Found by Peng
Li/Yueh-Hsun Lin, KNOX Security, Samsung Research America.
* Fix potential memory leak in mbedtls_x509_crl_parse(). The leak was caused
by missing calls to mbedtls_pem_free() in cases when a
MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT error was encountered. Found and
fix proposed by Guido Vranken. #722
* Fixed the templates used to generate project and solution files for Visual
Studio 2015 as well as the files themselves, to remove a build warning
generated in Visual Studio 2015. Reported by Steve Valliere. #742
* Fix a resource leak in ssl_cookie, when using MBEDTLS_THREADING_C.
Raised and fix suggested by Alan Gillingham in the mbed TLS forum. #771
* Fix 1 byte buffer overflow in mbedtls_mpi_write_string() when the MPI
number to write in hexadecimal is negative and requires an odd number of
digits. Found and fixed by Guido Vranken.
* Fix unlisted DES configuration dependency in some pkparse test cases. Found
by inestlerode. #555
= mbed TLS 2.4.1 branch released 2016-12-13
* Update to CMAC test data, taken from - NIST Special Publication 800-38B -
Recommendation for Block Cipher Modes of Operation: The CMAC Mode for
Authentication – October 2016
= mbed TLS 2.4.0 branch released 2016-10-17
* Removed the MBEDTLS_SSL_AEAD_RANDOM_IV option, because it was not compliant
with RFC-5116 and could lead to session key recovery in very long TLS
sessions. "Nonce-Disrespecting Adversaries Practical Forgery Attacks on GCM in
TLS" - H. Bock, A. Zauner, S. Devlin, J. Somorovsky, P. Jovanovic.
* Fixed potential stack corruption in mbedtls_x509write_crt_der() and
mbedtls_x509write_csr_der() when the signature is copied to the buffer
without checking whether there is enough space in the destination. The
issue cannot be triggered remotely. Found by Jethro Beekman.
* Added support for CMAC for AES and 3DES and AES-CMAC-PRF-128, as defined by
NIST SP 800-38B, RFC-4493 and RFC-4615.
* Added hardware entropy selftest to verify that the hardware entropy source
is functioning correctly.
* Added a script to print build environment info for diagnostic use in test
scripts, which is also now called by
* Added the macro MBEDTLS_X509_MAX_FILE_PATH_LEN that enables the user to
configure the maximum length of a file path that can be buffered when
calling mbedtls_x509_crt_parse_path().
* Added a configuration file config-no-entropy.h that configures the subset of
library features that do not require an entropy source.
* Added the macro MBEDTLS_ENTROPY_MIN_HARDWARE in config.h. This allows users
to configure the minimum number of bytes for entropy sources using the
mbedtls_hardware_poll() function.
* Fix for platform time abstraction to avoid dependency issues where a build
may need time but not the standard C library abstraction, and added
configuration consistency checks to check_config.h
* Fix dependency issue in Makefile to allow parallel builds.
* Fix incorrect handling of block lengths in crypt_and_hash.c sample program,
when GCM is used. Found by udf2457. #441
* Fix for key exchanges based on ECDH-RSA or ECDH-ECDSA which weren't
enabled unless others were also present. Found by David Fernandez. #428
* Fix for out-of-tree builds using CMake. Found by jwurzer, and fix based on
a contribution from Tobias Tangemann. #541
* Fixed cert_app.c sample program for debug output and for use when no root
certificates are provided.
* Fix conditional statement that would cause a 1 byte overread in
mbedtls_asn1_get_int(). Found and fixed by Guido Vranken. #599
* Fixed pthread implementation to avoid unintended double initialisations
and double frees. Found by Niklas Amnebratt.
* Fixed the sample applications gen_key.c, cert_req.c and cert_write.c for
builds where the configuration MBEDTLS_PEM_WRITE_C is not defined. Found
by inestlerode. #559.
* Fix mbedtls_x509_get_sig() to update the ASN1 type in the mbedtls_x509_buf
data structure until after error checks are successful. Found by
subramanyam-c. #622
* Fix documentation and implementation missmatch for function arguments of
mbedtls_gcm_finish(). Found by cmiatpaar. #602
* Guarantee that P>Q at RSA key generation. Found by inestlerode. #558
* Fix potential byte overread when verifying malformed SERVER_HELLO in
ssl_parse_hello_verify_request() for DTLS. Found by Guido Vranken.
* Fix check for validity of date when parsing in mbedtls_x509_get_time().
Found by subramanyam-c. #626
* Fix compatibility issue with Internet Explorer client authentication,
where the limited hash choices prevented the client from sending its
certificate. Found by teumas. #513
* Fix compilation without MBEDTLS_SELF_TEST enabled.
* Extended test coverage of special cases, and added new timing test suite.
* Removed self-tests from the script, and added all
missing self-tests to the test suites, to ensure self-tests are only
executed once.
* Added support for 3 and 4 byte lengths to mbedtls_asn1_write_len().
* Added support for a Yotta specific configuration file -
* Added optimization for code space for X.509/OID based on configured
features. Contributed by Aviv Palivoda.
* Renamed source file library/net.c to library/net_sockets.c to avoid
naming collision in projects which also have files with the common name
net.c. For consistency, the corresponding header file, net.h, is marked as
deprecated, and its contents moved to net_sockets.h.
* Changed the strategy for X.509 certificate parsing and validation, to no
longer disregard certificates with unrecognised fields.
= mbed TLS 2.3.0 branch released 2016-06-28
* Fix missing padding length check in mbedtls_rsa_rsaes_pkcs1_v15_decrypt
required by PKCS1 v2.2
* Fix potential integer overflow to buffer overflow in
mbedtls_rsa_rsaes_pkcs1_v15_encrypt and mbedtls_rsa_rsaes_oaep_encrypt
(not triggerable remotely in (D)TLS).
* Fix a potential integer underflow to buffer overread in
mbedtls_rsa_rsaes_oaep_decrypt. It is not triggerable remotely in
* Support for platform abstraction of the standard C library time()
* Fix bug in mbedtls_mpi_add_mpi() that caused wrong results when the three
arguments where the same (in-place doubling). Found and fixed by Janos
Follath. #309
* Fix potential build failures related to the 'apidoc' target, introduced
in the previous patch release. Found by Robert Scheck. #390 #391
* Fix issue in Makefile that prevented building using armar. #386
* Fix memory leak that occurred only when ECJPAKE was enabled and ECDHE and
ECDSA was disabled in config.h . The leak didn't occur by default.
* Fix an issue that caused valid certificates to be rejected whenever an
expired or not yet valid certificate was parsed before a valid certificate
in the trusted certificate list.
* Fix bug in mbedtls_x509_crt_parse that caused trailing extra data in the
buffer after DER certificates to be included in the raw representation.
* Fix issue that caused a hang when generating RSA keys of odd bitlength
* Fix bug in mbedtls_rsa_rsaes_pkcs1_v15_encrypt that made null pointer
dereference possible.
* Fix issue that caused a crash if invalid curves were passed to
mbedtls_ssl_conf_curves. #373
* Fix issue in ssl_fork_server which was preventing it from functioning. #429
* Fix memory leaks in test framework
* Fix test in that does not run properly with valgrind
* Fix unchecked calls to mmbedtls_md_setup(). Fix by Brian Murray. #502
* On ARM platforms, when compiling with -O0 with GCC, Clang or armcc5,
don't use the optimized assembly for bignum multiplication. This removes
the need to pass -fomit-frame-pointer to avoid a build error with -O0.
* Disabled SSLv3 in the default configuration.
* Optimized mbedtls_mpi_zeroize() for MPI integer size. (Fix by Alexey
* Fix non-compliance server extension handling. Extensions for SSLv3 are now
ignored, as required by RFC6101.
= mbed TLS 2.2.1 released 2016-01-05
* Fix potential double free when mbedtls_asn1_store_named_data() fails to
allocate memory. Only used for certificate generation, not triggerable
remotely in SSL/TLS. Found by Rafał Przywara. #367
* Disable MD5 handshake signatures in TLS 1.2 by default to prevent the
SLOTH attack on TLS 1.2 server authentication (other attacks from the
SLOTH paper do not apply to any version of mbed TLS or PolarSSL).
* Fix over-restrictive length limit in GCM. Found by Andreas-N. #362
* Fix bug in certificate validation that caused valid chains to be rejected
when the first intermediate certificate has pathLenConstraint=0. Found by
Nicholas Wilson. Introduced in mbed TLS 2.2.0. #280
* Removed potential leak in mbedtls_rsa_rsassa_pkcs1_v15_sign(), found by
JayaraghavendranK. #372
* Fix suboptimal handling of unexpected records that caused interop issues
with some peers over unreliable links. Avoid dropping an entire DTLS
datagram if a single record in a datagram is unexpected, instead only
drop the record and look at subsequent records (if any are present) in
the same datagram. Found by jeannotlapin. #345
= mbed TLS 2.2.0 released 2015-11-04
* Fix potential double free if mbedtls_ssl_conf_psk() is called more than
once and some allocation fails. Cannot be forced remotely. Found by Guido
Vranken, Intelworks.
* Fix potential heap corruption on Windows when
mbedtls_x509_crt_parse_path() is passed a path longer than 2GB. Cannot be
triggered remotely. Found by Guido Vranken, Intelworks.
* Fix potential buffer overflow in some asn1_write_xxx() functions.
Cannot be triggered remotely unless you create X.509 certificates based
on untrusted input or write keys of untrusted origin. Found by Guido
Vranken, Intelworks.
* The X509 max_pathlen constraint was not enforced on intermediate
certificates. Found by Nicholas Wilson, fix and tests provided by
Janos Follath. #280 and #319
* Experimental support for EC J-PAKE as defined in Thread 1.0.0.
Disabled by default as the specification might still change.
* Added a key extraction callback to accees the master secret and key
block. (Potential uses include EAP-TLS and Thread.)
* Self-signed certificates were not excluded from pathlen counting,
resulting in some valid X.509 being incorrectly rejected. Found and fix
provided by Janos Follath. #319
* Fix build error with configurations where ECDHE-PSK is the only key
exchange. Found and fix provided by Chris Hammond. #270
* Fix build error with configurations where RSA, RSA-PSK, ECDH-RSA or
ECHD-ECDSA if the only key exchange. Multiple reports. #310
* Fixed a bug causing some handshakes to fail due to some non-fatal alerts
not being properly ignored. Found by mancha and Kasom Koht-arsa, #308
* mbedtls_x509_crt_verify(_with_profile)() now also checks the key type and
size/curve against the profile. Before that, there was no way to set a
minimum key size for end-entity certificates with RSA keys. Found by
Matthew Page of Scannex Electronics Ltd.
* Fix failures in MPI on Sparc(64) due to use of bad assembly code.
Found by Kurt Danielson. #292
* Fix typo in name of the extKeyUsage OID. Found by inestlerode, #314
* Fix bug in ASN.1 encoding of booleans that caused generated CA
certificates to be rejected by some applications, including OS X
Keychain. Found and fixed by Jonathan Leroy, Inikup.
* Improved performance of mbedtls_ecp_muladd() when one of the scalars is 1
or -1.
= mbed TLS 2.1.2 released 2015-10-06
* Added fix for CVE-2015-5291 to prevent heap corruption due to buffer
overflow of the hostname or session ticket. Found by Guido Vranken,
* Fix potential double-free if mbedtls_ssl_set_hs_psk() is called more than
once in the same handhake and mbedtls_ssl_conf_psk() was used.
Found and patch provided by Guido Vranken, Intelworks. Cannot be forced
* Fix stack buffer overflow in pkcs12 decryption (used by
mbedtls_pk_parse_key(file)() when the password is > 129 bytes.
Found by Guido Vranken, Intelworks. Not triggerable remotely.
* Fix potential buffer overflow in mbedtls_mpi_read_string().
Found by Guido Vranken, Intelworks. Not exploitable remotely in the context
of TLS, but might be in other uses. On 32 bit machines, requires reading a
string of close to or larger than 1GB to exploit; on 64 bit machines, would
require reading a string of close to or larger than 2^62 bytes.
* Fix potential random memory allocation in mbedtls_pem_read_buffer()
on crafted PEM input data. Found and fix provided by Guido Vranken,
Intelworks. Not triggerable remotely in TLS. Triggerable remotely if you
accept PEM data from an untrusted source.
* Fix possible heap buffer overflow in base64_encoded() when the input
buffer is 512MB or larger on 32-bit platforms. Found by Guido Vranken,
Intelworks. Not trigerrable remotely in TLS.
* Fix potential double-free if mbedtls_conf_psk() is called repeatedly on
the same mbedtls_ssl_config object and memory allocation fails. Found by
Guido Vranken, Intelworks. Cannot be forced remotely.
* Fix potential heap buffer overflow in servers that perform client
authentication against a crafted CA cert. Cannot be triggered remotely
unless you allow third parties to pick trust CAs for client auth.
Found by Guido Vranken, Intelworks.
* Fix compile error in net.c with musl libc. Found and patch provided by
zhasha (#278).
* Fix macroization of 'inline' keyword when building as C++. (#279)
* Added checking of hostname length in mbedtls_ssl_set_hostname() to ensure
domain names are compliant with RFC 1035.
* Fixed paths for check_config.h in example config files. (Found by bachp)
= mbed TLS 2.1.1 released 2015-09-17
* Add countermeasure against Lenstra's RSA-CRT attack for PKCS#1 v1.5
signatures. (Found by Florian Weimer, Red Hat.)
* Fix possible client-side NULL pointer dereference (read) when the client
tries to continue the handshake after it failed (a misuse of the API).
(Found and patch provided by Fabian Foerg, Gotham Digital Science using
* Fix warning when using a 64bit platform. (found by embedthis) (#275)
* Fix off-by-one error in parsing Supported Point Format extension that
caused some handshakes to fail.
* Made X509 profile pointer const in mbedtls_ssl_conf_cert_profile() to allow
use of mbedtls_x509_crt_profile_next. (found by NWilson)
* When a client initiates a reconnect from the same port as a live
connection, if cookie verification is available
(MBEDTLS_SSL_DTLS_HELLO_VERIFY defined in config.h, and usable cookie
callbacks set with mbedtls_ssl_conf_dtls_cookies()), this will be
detected and mbedtls_ssl_read() will return
MBEDTLS_ERR_SSL_CLIENT_RECONNECT - it is then possible to start a new
handshake with the same context. (See RFC 6347 section 4.2.8.)
= mbed TLS 2.1.0 released 2015-09-04
* Added support for yotta as a build system.
* Primary open source license changed to Apache 2.0 license.
* Fix segfault in the benchmark program when benchmarking DHM.
* Fix build error with CMake and pre-4.5 versions of GCC (found by Hugo
* Fix bug when parsing a ServerHello without extensions (found by David
* Fix bug in CMake lists that caused libmbedcrypto.a not to be installed
(found by Benoit Lecocq).
* Fix bug in Makefile that caused libmbedcrypto and libmbedx509 not to be
installed (found by Rawi666).
* Fix compile error with armcc 5 with --gnu option.
* Fix bug in Makefile that caused programs not to be installed correctly
(found by robotanarchy) (#232).
* Fix bug in Makefile that prevented from installing without building the
tests (found by robotanarchy) (#232).
* Fix missing -static-libgcc when building shared libraries for Windows
with make.
* Fix link error when building shared libraries for Windows with make.
* Fix error when loading
* Fix bug in mbedtls_ssl_conf_default() that caused the default preset to
be always used (found by dcb314) (#235)
* Fix bug in mbedtls_rsa_public() and mbedtls_rsa_private() that could
result trying to unlock an unlocked mutex on invalid input (found by
Fredrik Axelsson) (#257)
* Fix -Wshadow warnings (found by hnrkp) (#240)
* Fix memory corruption on client with overlong PSK identity, around
SSL_MAX_CONTENT_LEN or higher - not triggerrable remotely (found by
Aleksandrs Saveljevs) (#238)
* Fix unused function warning when using MBEDTLS_MDx_ALT or
MBEDTLS_SHAxxx_ALT (found by Henrik) (#239)
* Fix memory corruption in pkey programs (found by yankuncheng) (#210)
* The PEM parser now accepts a trailing space at end of lines (#226).
* It is now possible to #include a user-provided configuration file at the
end of the default config.h by defining MBEDTLS_USER_CONFIG_FILE on the
compiler's command line.
* When verifying a certificate chain, if an intermediate certificate is
trusted, no later cert is checked. (suggested by hannes-landeholm)
* Prepend a "thread identifier" to debug messages (issue pointed out by
Hugo Leisink) (#210).
* Add mbedtls_ssl_get_max_frag_len() to query the current maximum fragment
= mbed TLS 2.0.0 released 2015-07-13
* Support for DTLS 1.0 and 1.2 (RFC 6347).
* Ability to override core functions from MDx, SHAx, AES and DES modules
with custom implementation (eg hardware accelerated), complementing the
ability to override the whole module.
* New server-side implementation of session tickets that rotate keys to
preserve forward secrecy, and allows sharing across multiple contexts.
* Added a concept of X.509 cerificate verification profile that controls
which algorithms and key sizes (curves for ECDSA) are acceptable.
* Expanded configurability of security parameters in the SSL module with
mbedtls_ssl_conf_dhm_min_bitlen() and mbedtls_ssl_conf_sig_hashes().
* Introduced a concept of presets for SSL security-relevant configuration
API Changes
* The library has been split into libmbedcrypto, libmbedx509, libmbedtls.
You now need to link to all of them if you use TLS for example.
* All public identifiers moved to the mbedtls_* or MBEDTLS_* namespace.
Some names have been further changed to make them more consistent.
Migration helpers scripts/ and include/mbedtls/compat-1.3.h are
provided. Full list of renamings in scripts/data_files/rename-1.3-2.0.txt
* Renamings of fields inside structures, not covered by the previous list:
mbedtls_cipher_info_t.key_length -> key_bitlen
mbedtls_cipher_context_t.key_length -> key_bitlen
mbedtls_ecp_curve_info.size -> bit_size
* Headers are now found in the 'mbedtls' directory (previously 'polarssl').
* The following _init() functions that could return errors have
been split into an _init() that returns void and another function that
should generally be the first function called on this context after init:
mbedtls_ssl_init() -> mbedtls_ssl_setup()
mbedtls_ccm_init() -> mbedtls_ccm_setkey()
mbedtls_gcm_init() -> mbedtls_gcm_setkey()
mbedtls_hmac_drbg_init() -> mbedtls_hmac_drbg_seed(_buf)()
mbedtls_ctr_drbg_init() -> mbedtls_ctr_drbg_seed()
Note that for mbedtls_ssl_setup(), you need to be done setting up the
ssl_config structure before calling it.
* Most ssl_set_xxx() functions (all except ssl_set_bio(), ssl_set_hostname(),
ssl_set_session() and ssl_set_client_transport_id(), plus
ssl_legacy_renegotiation()) have been renamed to mbedtls_ssl_conf_xxx()
(see and compat-1.3.h above) and their first argument's type
changed from ssl_context to ssl_config.
* ssl_set_bio() changed signature (contexts merged, order switched, one
additional callback for read-with-timeout).
* The following functions have been introduced and must be used in callback
implementations (SNI, PSK) instead of their *conf counterparts:
* mbedtls_ssl_conf_ca_chain() lost its last argument (peer_cn), now set
using mbedtls_ssl_set_hostname().
* mbedtls_ssl_conf_session_cache() changed prototype (only one context
pointer, parameters reordered).
* On server, mbedtls_ssl_conf_session_tickets_cb() must now be used in
place of mbedtls_ssl_conf_session_tickets() to enable session tickets.
* The SSL debug callback gained two new arguments (file name, line number).
* Debug modes were removed.
* mbedtls_ssl_conf_truncated_hmac() now returns void.
* mbedtls_memory_buffer_alloc_init() now returns void.
* X.509 verification flags are now an uint32_t. Affect the signature of:
mbedtls_x509_crt_verify() (flags, f_vrfy -> needs to be updated)
mbedtls_ssl_conf_verify() (f_vrfy -> needs to be updated)
* The following functions changed prototype to avoid an in-out length
* In the NET module, all "int" and "int *" arguments for file descriptors
changed type to "mbedtls_net_context *".
* net_accept() gained new arguments for the size of the client_ip buffer.
* In the threading layer, mbedtls_mutex_init() and mbedtls_mutex_free() now
return void.
* ecdsa_write_signature() gained an additional md_alg argument and
ecdsa_write_signature_det() was deprecated.
* pk_sign() no longer accepts md_alg == POLARSSL_MD_NONE with ECDSA.
* Last argument of x509_crt_check_key_usage() and
mbedtls_x509write_crt_set_key_usage() changed from int to unsigned.
* test_ca_list (from certs.h) is renamed to test_cas_pem and is only
available if POLARSSL_PEM_PARSE_C is defined (it never worked without).
* Test certificates in certs.c are no longer guaranteed to be nul-terminated
strings; use the new *_len variables instead of strlen().
* Functions mbedtls_x509_xxx_parse(), mbedtls_pk_parse_key(),
mbedtls_pk_parse_public_key() and mbedtls_dhm_parse_dhm() now expect the
length parameter to include the terminating null byte for PEM input.
* Signature of mpi_mul_mpi() changed to make the last argument unsigned
* calloc() is now used instead of malloc() everywhere. API of platform
layer and the memory_buffer_alloc module changed accordingly.
(Thanks to Mansour Moufid for helping with the replacement.)
(support for renegotiation now needs explicit enabling in config.h).
in config.h
* net_connect() and net_bind() have a new 'proto' argument to choose
between TCP and UDP, using the macros NET_PROTO_TCP or NET_PROTO_UDP.
Their 'port' argument type is changed to a string.
* Some constness fixes
* Removed mbedtls_ecp_group_read_string(). Only named groups are supported.
* Removed mbedtls_ecp_sub() and mbedtls_ecp_add(), use
* Removed individual mdX_hmac, shaX_hmac, mdX_file and shaX_file functions
(use generic functions from md.h)
* Removed mbedtls_timing_msleep(). Use mbedtls_net_usleep() or a custom
waiting function.
* Removed test DHM parameters from the test certs module.
* Removed the PBKDF2 module (use PKCS5).
* Removed POLARSSL_ERROR_STRERROR_BC (use mbedtls_strerror()).
* Removed compat-1.2.h (helper for migrating from 1.2 to 1.3).
* Removed openssl.h (very partial OpenSSL compatibility layer).
* Configuration options POLARSSL_HAVE_LONGLONG was removed (now always on).
* Configuration options POLARSSL_HAVE_INT8 and POLARSSL_HAVE_INT16 have
been removed (compiler is required to support 32-bit operations).
* Configuration option POLARSSL_HAVE_IPV6 was removed (always enabled).
* Removed test program o_p_test, the script does more.
* Removed test program ssl_test, superseded by
* Removed helper script
New deprecations
* md_init_ctx() is deprecated in favour of md_setup(), that adds a third
argument (allowing memory savings if HMAC is not used)
Semi-API changes (technically public, morally private)
* Renamed a few headers to include _internal in the name. Those headers are
not supposed to be included by users.
* Changed md_info_t into an opaque structure (use md_get_xxx() accessors).
* Changed pk_info_t into an opaque structure.
* Changed cipher_base_t into an opaque structure.
* Removed sig_oid2 and rename sig_oid1 to sig_oid in x509_crt and x509_crl.
* x509_crt.key_usage changed from unsigned char to unsigned int.
* Removed r and s from ecdsa_context
* Removed mode from des_context and des3_context
Default behavior changes
* The default minimum TLS version is now TLS 1.0.
* RC4 is now blacklisted by default in the SSL/TLS layer, and excluded from the
default ciphersuite list returned by ssl_list_ciphersuites()
* Support for receiving SSLv2 ClientHello is now disabled by default at
compile time.
* The default authmode for SSL/TLS clients is now REQUIRED.
* Support for RSA_ALT contexts in the PK layer is now optional. Since is is
enabled in the default configuration, this is only noticeable if using a
custom config.h
* Default DHM parameters server-side upgraded from 1024 to 2048 bits.
* A minimum RSA key size of 2048 bits is now enforced during ceritificate
chain verification.
* Negotiation of truncated HMAC is now disabled by default on server too.
* The following functions are now case-sensitive:
Requirement changes
* The minimum MSVC version required is now 2010 (better C99 support).
* The NET layer now unconditionnaly relies on getaddrinfo() and select().
* Compiler is required to support C99 types such as long long and uint32_t.
API changes from the 1.4 preview branch
* ssl_set_bio_timeout() was removed, split into mbedtls_ssl_set_bio() with
new prototype, and mbedtls_ssl_set_read_timeout().
* The following functions now return void:
* DTLS no longer hard-depends on TIMING_C, but uses a callback interface
instead, see mbedtls_ssl_set_timer_cb(), with the Timing module providing
an example implementation, see mbedtls_timing_delay_context and
* With UDP sockets, it is no longer necessary to call net_bind() again
after a successful net_accept().
* mbedtls_ctr_drbg_random() and mbedtls_hmac_drbg_random() are now
thread-safe if MBEDTLS_THREADING_C is enabled.
* Reduced ROM fooprint of SHA-256 and added an option to reduce it even
more (at the expense of performance) MBEDTLS_SHA256_SMALLER.
= mbed TLS 1.3 branch
* With authmode set to SSL_VERIFY_OPTIONAL, verification of keyUsage and
extendedKeyUsage on the leaf certificate was lost (results not accessible
via ssl_get_verify_results()).
* Add countermeasure against "Lucky 13 strikes back" cache-based attack,
* Improve ECC performance by using more efficient doubling formulas
(contributed by Peter Dettman).
* Add x509_crt_verify_info() to display certificate verification results.
* Add support for reading DH parameters with privateValueLength included
(contributed by Daniel Kahn Gillmor).
* Add support for bit strings in X.509 names (request by Fredrik Axelsson).
* Add support for id-at-uniqueIdentifier in X.509 names.
* Add support for overriding snprintf() (except on Windows) and exit() in
the platform layer.
* Add an option to use macros instead of function pointers in the platform
layer (helps get rid of unwanted references).
* Improved Makefiles for Windows targets by fixing library targets and making
cross-compilation easier (thanks to Alon Bar-Lev).
* The benchmark program also prints heap usage for public-key primitives
* New script helps measuring the impact of ECC parameters on
speed and RAM (heap only for now) usage.
* New script helps measuring the ROM and RAM requirements of two
reduced configurations (PSK-CCM and NSA suite B).
* Add config flag POLARSSL_DEPRECATED_WARNING (off by default) to produce
warnings on use of deprecated functions (with GCC and Clang only).
* Add config flag POLARSSL_DEPRECATED_REMOVED (off by default) to produce
errors on use of deprecated functions.
* Fix compile errors with PLATFORM_NO_STD_FUNCTIONS.
* Fix compile error with PLATFORM_EXIT_ALT (thanks to Rafał Przywara).
* Fix bug in entropy.c when THREADING_C is also enabled that caused
entropy_free() to crash (thanks to Rafał Przywara).
* Fix memory leak when gcm_setkey() and ccm_setkey() are used more than
once on the same context.
* Fix bug in ssl_mail_client when password is longer that username (found
by Bruno Pape).
* Fix undefined behaviour (memcmp( NULL, NULL, 0 );) in X.509 modules
(detected by Clang's 3.6 UBSan).
* mpi_size() and mpi_msb() would segfault when called on an mpi that is
initialized but not set (found by pravic).
* Fix detection of support for getrandom() on Linux (reported by syzzer) by
doing it at runtime (using uname) rather that compile time.
* Fix handling of symlinks by "make install" (found by Gaël PORTAY).
* Fix potential NULL pointer dereference (not trigerrable remotely) when
ssl_write() is called before the handshake is finished (introduced in
1.3.10) (first reported by Martin Blumenstingl).
* Fix bug in pk_parse_key() that caused some valid private EC keys to be
* Fix bug in Via Padlock support (found by Nikos Mavrogiannopoulos).
* Fix thread safety bug in RSA operations (found by Fredrik Axelsson).
* Fix hardclock() (only used in the benchmarking program) with some
versions of mingw64 (found by kxjhlele).
* Fix warnings from mingw64 in timing.c (found by kxjklele).
* Fix potential unintended sign extension in asn1_get_len() on 64-bit
* Fix potential memory leak in ssl_set_psk() (found by Mansour Moufid).
* Fix compile error when POLARSSL_SSL_DISABLE_RENEGOTATION and
POLARSSL_SSL_SSESSION_TICKETS where both enabled in config.h (introduced
in 1.3.10).
* Add missing extern "C" guard in aesni.h (reported by amir zamani).
* Add missing dependency on SHA-256 in some x509 programs (reported by
Gergely Budai).
* Fix bug related to ssl_set_curves(): the client didn't check that the
curve picked by the server was actually allowed.
* Remove bias in mpi_gen_prime (contributed by Pascal Junod).
* Remove potential sources of timing variations (some contributed by Pascal
* Options POLARSSL_HAVE_INT8 and POLARSSL_HAVE_INT16 are deprecated.
* Enabling POLARSSL_NET_C without POLARSSL_HAVE_IPV6 is deprecated.
* compat-1.2.h and openssl.h are deprecated.
* Adjusting/overriding CFLAGS and LDFLAGS with the make build system is now
more flexible (warning: OFLAGS is not used any more) (see the README)
(contributed by Alon Bar-Lev).
* ssl_set_own_cert() no longer calls pk_check_pair() since the
performance impact was bad for some users (this was introduced in 1.3.10).
* Move from SHA-1 to SHA-256 in example programs using signatures
(suggested by Thorsten Mühlfelder).
* Remove some unneeded inclusions of header files from the standard library
"minimize" others (eg use stddef.h if only size_t is needed).
* Change #include lines in test files to use double quotes instead of angle
brackets for uniformity with the rest of the code.
* Remove dependency on sscanf() in X.509 parsing modules.
= mbed TLS 1.3.10 released 2015-02-09
* NULL pointer dereference in the buffer-based allocator when the buffer is
full and polarssl_free() is called (found by Mark Hasemeyer)
(only possible if POLARSSL_MEMORY_BUFFER_ALLOC_C is enabled, which it is
not by default).
* Fix remotely-triggerable uninitialised pointer dereference caused by
crafted X.509 certificate (TLS server is not affected if it doesn't ask for a
client certificate) (found using Codenomicon Defensics).
* Fix remotely-triggerable memory leak caused by crafted X.509 certificates
(TLS server is not affected if it doesn't ask for a client certificate)
(found using Codenomicon Defensics).
* Fix potential stack overflow while parsing crafted X.509 certificates
(TLS server is not affected if it doesn't ask for a client certificate)
(found using Codenomicon Defensics).
* Fix timing difference that could theoretically lead to a
Bleichenbacher-style attack in the RSA and RSA-PSK key exchanges
(reported by Sebastian Schinzel).
* Add support for FALLBACK_SCSV (draft-ietf-tls-downgrade-scsv).
* Add support for Extended Master Secret (draft-ietf-tls-session-hash).
* Add support for Encrypt-then-MAC (RFC 7366).
* Add function pk_check_pair() to test if public and private keys match.
* Add x509_crl_parse_der().
* Add compile-time option POLARSSL_X509_MAX_INTERMEDIATE_CA to limit the
length of an X.509 verification chain.
* Support for renegotiation can now be disabled at compile-time
* Support for 1/n-1 record splitting, a countermeasure against BEAST.
* Certificate selection based on signature hash, preferring SHA-1 over SHA-2
for pre-1.2 clients when multiple certificates are available.
* Add support for getrandom() syscall on recent Linux kernels with Glibc or
a compatible enough libc (eg uClibc).
* Add ssl_set_arc4_support() to make it easier to disable RC4 at runtime
while using the default ciphersuite list.
* Added new error codes and debug messages about selection of
* Stack buffer overflow if ctr_drbg_update() is called with too large
add_len (found by Jean-Philippe Aumasson) (not triggerable remotely).
* Possible buffer overflow of length at most POLARSSL_MEMORY_ALIGN_MULTIPLE
if memory_buffer_alloc_init() was called with buf not aligned and len not
a multiple of POLARSSL_MEMORY_ALIGN_MULTIPLE (not triggerable remotely).
* User set CFLAGS were ignored by Cmake with gcc (introduced in 1.3.9, found
by Julian Ospald).
* Fix potential undefined behaviour in Camellia.
* Fix potential failure in ECDSA signatures when POLARSSL_ECP_MAX_BITS is a
multiple of 8 (found by Gergely Budai).
* Fix unchecked return code in x509_crt_parse_path() on Windows (found by
Peter Vaskovic).
* Fix assembly selection for MIPS64 (thanks to James Cowgill).
* ssl_get_verify_result() now works even if the handshake was aborted due
to a failed verification (found by Fredrik Axelsson).
* Skip writing and parsing signature_algorithm extension if none of the
key exchanges enabled needs certificates. This fixes a possible interop
issue with some servers when a zero-length extension was sent. (Reported
by Peter Dettman.)
* On a 0-length input, base64_encode() did not correctly set output length
(found by Hendrik van den Boogaard).
* Use deterministic nonces for AEAD ciphers in TLS by default (possible to
switch back to random with POLARSSL_SSL_AEAD_RANDOM_IV in config.h).
* Blind RSA private operations even when POLARSSL_RSA_NO_CRT is defined.
* ssl_set_own_cert() now returns an error on key-certificate mismatch.
* Forbid repeated extensions in X.509 certificates.
* debug_print_buf() now prints a text view in addition to hexadecimal.
* A specific error is now returned when there are ciphersuites in common
but none of them is usable due to external factors such as no certificate
with a suitable (extended)KeyUsage or curve or no PSK set.
* It is now possible to disable negotiation of truncated HMAC server-side
at runtime with ssl_set_truncated_hmac().
* Example programs for SSL client and server now disable SSLv3 by default.
* Example programs for SSL client and server now disable RC4 by default.
* Use platform.h in all test suites and programs.
= PolarSSL 1.3.9 released 2014-10-20
* Lowest common hash was selected from signature_algorithms extension in
TLS 1.2 (found by Darren Bane) (introduced in 1.3.8).
* Remotely-triggerable memory leak when parsing some X.509 certificates
(server is not affected if it doesn't ask for a client certificate)
(found using Codenomicon Defensics).
* Remotely-triggerable memory leak when parsing crafted ClientHello
(not affected if ECC support was compiled out) (found using Codenomicon
* Support escaping of commas in x509_string_to_names()
* Fix compile error in ssl_pthread_server (found by Julian Ospald).
* Fix net_accept() regarding non-blocking sockets (found by Luca Pesce).
* Don't print uninitialised buffer in ssl_mail_client (found by Marc Abel).
* Fix warnings from Clang's scan-build (contributed by Alfred Klomp).
* Fix compile error in timing.c when POLARSSL_NET_C and POLARSSL_SELFTEST
are defined but not POLARSSL_HAVE_TIME (found by Stephane Di Vito).
* Remove non-existent file from VS projects (found by Peter Vaskovic).
* ssl_read() could return non-application data records on server while
renegotation was pending, and on client when a HelloRequest was received.
* Server-initiated renegotiation would fail with non-blocking I/O if the
write callback returned WANT_WRITE when requesting renegotiation.
* ssl_close_notify() could send more than one message in some circumstances
with non-blocking I/O.
* Fix compiler warnings on iOS (found by Sander Niemeijer).
* x509_crt_parse() did not increase total_failed on PEM error
* Fix compile error with armcc in mpi_is_prime()
* Fix potential bad read in parsing ServerHello (found by Adrien
* Ciphersuites using SHA-256 or SHA-384 now require TLS 1.x (there is no
standard defining how to use SHA-2 with SSL 3.0).
* Ciphersuites using RSA-PSK key exchange new require TLS 1.x (the spec is
ambiguous on how to encode some packets with SSL 3.0).
* Made buffer size in pk_write_(pub)key_pem() more dynamic, eg smaller if
RSA is disabled, larger if POLARSSL_MPI_MAX_SIZE is larger.
* ssl_read() now returns POLARSSL_ERR_NET_WANT_READ rather than
* POLARSSL_MPI_MAX_SIZE now defaults to 1024 in order to allow 8192 bits
RSA keys.
* Accept spaces at end of line or end of buffer in base64_decode().
* X.509 certificates with more than one AttributeTypeAndValue per
RelativeDistinguishedName are not accepted any more.
= PolarSSL 1.3.8 released 2014-07-11
* Fix length checking for AEAD ciphersuites (found by Codenomicon).
It was possible to crash the server (and client) using crafted messages
when a GCM suite was chosen.
* Add CCM module and cipher mode to Cipher Layer
* Support for CCM and CCM_8 ciphersuites
* Support for parsing and verifying RSASSA-PSS signatures in the X.509
modules (certificates, CRLs and CSRs).
* Blowfish in the cipher layer now supports variable length keys.
* Add example config.h for PSK with CCM, optimized for low RAM usage.
* Optimize for RAM usage in example config.h for NSA Suite B profile.
* Add POLARSSL_REMOVE_ARC4_CIPHERSUITES to allow removing RC4 ciphersuites
from the default list (inactive by default).
* Add server-side enforcement of sent renegotiation requests
* Add SSL_CIPHERSUITES config.h flag to allow specifying a list of
ciphersuites to use and save some memory if the list is small.
* Add LINK_WITH_PTHREAD option in CMake for explicit linking that is
required on some platforms (e.g. OpenBSD)
* Migrate zeroizing of data to polarssl_zeroize() instead of memset()
against unwanted compiler optimizations
* md_list() now returns hashes strongest first
* Selection of hash for signing ServerKeyExchange in TLS 1.2 now picks
strongest offered by client.
* All public contexts have _init() and _free() functions now for simpler
usage pattern
* Fix in debug_print_msg()
* Enforce alignment in the buffer allocator even if buffer is not aligned
* Remove less-than-zero checks on unsigned numbers
* Stricter check on SSL ClientHello internal sizes compared to actual packet
size (found by TrustInSoft)
* Fix WSAStartup() return value check (found by Peter Vaskovic)
* Other minor issues (found by Peter Vaskovic)
* Fix symlink command for cross compiling with CMake (found by Andre
* Fix DER output of gen_key app (found by Gergely Budai)
* Very small records were incorrectly rejected when truncated HMAC was in
use with some ciphersuites and versions (RC4 in all versions, CBC with
versions < TLS 1.1).
* Very large records using more than 224 bytes of padding were incorrectly
rejected with CBC-based ciphersuites and TLS >= 1.1
* Very large records using less padding could cause a buffer overread of up
to 32 bytes with CBC-based ciphersuites and TLS >= 1.1
* Restore ability to use a v1 cert as a CA if trusted locally. (This had
been removed in 1.3.6.)
* Restore ability to locally trust a self-signed cert that is not a proper
CA for use as an end entity certificate. (This had been removed in
* Fix preprocessor checks for bn_mul PPC asm (found by Barry K. Nathan).
* Use \n\t rather than semicolons for bn_mul asm, since some assemblers
interpret semicolons as comment delimiters (found by Barry K. Nathan).
* Fix off-by-one error in parsing Supported Point Format extension that
caused some handshakes to fail.
* Fix possible miscomputation of the premaster secret with DHE-PSK key
exchange that caused some handshakes to fail with other implementations.
(Failure rate <= 1/255 with common DHM moduli.)
* Disable broken Sparc64 bn_mul assembly (found by Florian Obser).
* Fix base64_decode() to return and check length correctly (in case of
tight buffers)
* Fix mpi_write_string() to write "00" as hex output for empty MPI (found
by Hui Dong)
= PolarSSL 1.3.7 released on 2014-05-02
* debug_set_log_mode() added to determine raw or full logging
* debug_set_threshold() added to ignore messages over threshold level
* version_check_feature() added to check for compile-time options at
* POLARSSL_CONFIG_OPTIONS has been removed. All values are individually
checked and filled in the relevant module headers
* Debug module only outputs full lines instead of parts
* Better support for the different Attribute Types from IETF PKIX (RFC 5280)
* AES-NI now compiles with "old" assemblers too
* Ciphersuites based on RC4 now have the lowest priority by default
* Only iterate over actual certificates in ssl_write_certificate_request()
(found by Matthew Page)
* Typos in platform.c and pkcs11.c (found by Daniel Phillips and Steffan
* cert_write app should use subject of issuer certificate as issuer of cert
* Fix false reject in padding check in ssl_decrypt_buf() for CBC
ciphersuites, for full SSL frames of data.
* Improve interoperability by not writing extension length in ClientHello /
ServerHello when no extensions are present (found by Matthew Page)
* rsa_check_pubkey() now allows an E up to N
* On OpenBSD, use arc4random_buf() instead of rand() to prevent warnings
* mpi_fill_random() was creating numbers larger than requested on
big-endian platform when size was not an integer number of limbs
* Fix dependencies issues in X.509 test suite.
* Some parts of ssl_tls.c were compiled even when the module was disabled.
* Fix detection of DragonflyBSD in net.c (found by Markus Pfeiffer)
* Fix detection of Clang on some Apple platforms with CMake
(found by Barry K. Nathan)
= PolarSSL 1.3.6 released on 2014-04-11