Upgrade the default X.509 profile to the former "next" profile
Upgrade the default X.509 certificate verification profile
mbedtls_x509_crt_profile_default to the former value of
mbedtls_x509_crt_profile_next, which is hashes and curves with at least 255
bits (Curve25519 included), and RSA 2048 and above.
Document more precisely what goes into the default profile.
Keep the "next" profile unchanged for now.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/include/mbedtls/x509_crt.h b/include/mbedtls/x509_crt.h
index d383168..9c7016d 100644
--- a/include/mbedtls/x509_crt.h
+++ b/include/mbedtls/x509_crt.h
@@ -332,12 +332,22 @@
/**
* Default security profile. Should provide a good balance between security
* and compatibility with current deployments.
+ *
+ * This profile permits:
+ * - SHA2 hashes with at least 256 bits: SHA-256, SHA-384, SHA-512.
+ * - Elliptic curves with 255 bits and above.
+ * - RSA with 2048 bits and above.
+ *
+ * New minor versions of Mbed TLS may extend this profile, for example if
+ * new curves are added to the library. New minor versions of Mbed TLS will
+ * not reduce this profile unless serious security concerns require it.
*/
extern const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_default;
/**
* Expected next default profile. Recommended for new deployments.
- * Currently targets a 128-bit security level, except for RSA-2048.
+ * Currently targets a 128-bit security level, except for allowing RSA-2048.
+ * This profile may change at any time.
*/
extern const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_next;
diff --git a/library/x509_crt.c b/library/x509_crt.c
index d4e0ffd..5969247 100644
--- a/library/x509_crt.c
+++ b/library/x509_crt.c
@@ -95,26 +95,10 @@
*/
#define X509_MAX_VERIFY_CHAIN_SIZE ( MBEDTLS_X509_MAX_INTERMEDIATE_CA + 2 )
-/*
- * Default profile
- */
+/* Default profile. Do not remove items unless there are serious security
+ * concerns. */
const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_default =
{
- /* Only SHA-2 hashes */
- MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA224 ) |
- MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA256 ) |
- MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA384 ) |
- MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA512 ),
- 0xFFFFFFF, /* Any PK alg */
- 0xFFFFFFF, /* Any curve */
- 2048,
-};
-
-/*
- * Next-default profile
- */
-const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_next =
-{
/* Hashes from SHA-256 and above */
MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA256 ) |
MBEDTLS_X509_ID_FLAG( MBEDTLS_MD_SHA384 ) |
@@ -135,6 +119,11 @@
2048,
};
+/* Next-generation profile. Currently identical to the default, but may
+ * be tightened at any time. */
+const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_next =
+ mbedtls_x509_crt_profile_default;
+
/*
* NSA Suite B Profile
*/
