/* | |
* The RSA public-key cryptosystem | |
* | |
* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved | |
* SPDX-License-Identifier: Apache-2.0 | |
* | |
* Licensed under the Apache License, Version 2.0 (the "License"); you may | |
* not use this file except in compliance with the License. | |
* You may obtain a copy of the License at | |
* | |
* http://www.apache.org/licenses/LICENSE-2.0 | |
* | |
* Unless required by applicable law or agreed to in writing, software | |
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT | |
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
* See the License for the specific language governing permissions and | |
* limitations under the License. | |
* | |
* This file is part of mbed TLS (https://tls.mbed.org) | |
*/ | |
/* | |
* The following sources were referenced in the design of this implementation | |
* of the RSA algorithm: | |
* | |
* [1] A method for obtaining digital signatures and public-key cryptosystems | |
* R Rivest, A Shamir, and L Adleman | |
* http://people.csail.mit.edu/rivest/pubs.html#RSA78 | |
* | |
* [2] Handbook of Applied Cryptography - 1997, Chapter 8 | |
* Menezes, van Oorschot and Vanstone | |
* | |
* [3] Malware Guard Extension: Using SGX to Conceal Cache Attacks | |
* Michael Schwarz, Samuel Weiser, Daniel Gruss, Clémentine Maurice and | |
* Stefan Mangard | |
* https://arxiv.org/abs/1702.08719v2 | |
* | |
*/ | |
#if !defined(MBEDTLS_CONFIG_FILE) | |
#include "mbedtls/config.h" | |
#else | |
#include MBEDTLS_CONFIG_FILE | |
#endif | |
#if defined(MBEDTLS_RSA_C) | |
#include "mbedtls/rsa.h" | |
#include "mbedtls/rsa_internal.h" | |
#include "mbedtls/oid.h" | |
#include "mbedtls/platform_util.h" | |
#include <string.h> | |
#if defined(MBEDTLS_PKCS1_V21) | |
#include "mbedtls/md.h" | |
#endif | |
#if defined(MBEDTLS_PKCS1_V15) && !defined(__OpenBSD__) | |
#include <stdlib.h> | |
#endif | |
#if defined(MBEDTLS_PLATFORM_C) | |
#include "mbedtls/platform.h" | |
#else | |
#include <stdio.h> | |
#define mbedtls_printf printf | |
#define mbedtls_calloc calloc | |
#define mbedtls_free free | |
#endif | |
#if !defined(MBEDTLS_RSA_ALT) | |
/* Parameter validation macros */ | |
#define RSA_VALIDATE_RET( cond ) \ | |
MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_RSA_BAD_INPUT_DATA ) | |
#define RSA_VALIDATE( cond ) \ | |
MBEDTLS_INTERNAL_VALIDATE( cond ) | |
#if defined(MBEDTLS_PKCS1_V15) | |
/* constant-time buffer comparison */ | |
static inline int mbedtls_safer_memcmp( const void *a, const void *b, size_t n ) | |
{ | |
size_t i; | |
const unsigned char *A = (const unsigned char *) a; | |
const unsigned char *B = (const unsigned char *) b; | |
unsigned char diff = 0; | |
for( i = 0; i < n; i++ ) | |
diff |= A[i] ^ B[i]; | |
return( diff ); | |
} | |
#endif /* MBEDTLS_PKCS1_V15 */ | |
int mbedtls_rsa_import( mbedtls_rsa_context *ctx, | |
const mbedtls_mpi *N, | |
const mbedtls_mpi *P, const mbedtls_mpi *Q, | |
const mbedtls_mpi *D, const mbedtls_mpi *E ) | |
{ | |
int ret; | |
RSA_VALIDATE_RET( ctx != NULL ); | |
if( ( N != NULL && ( ret = mbedtls_mpi_copy( &ctx->N, N ) ) != 0 ) || | |
( P != NULL && ( ret = mbedtls_mpi_copy( &ctx->P, P ) ) != 0 ) || | |
( Q != NULL && ( ret = mbedtls_mpi_copy( &ctx->Q, Q ) ) != 0 ) || | |
( D != NULL && ( ret = mbedtls_mpi_copy( &ctx->D, D ) ) != 0 ) || | |
( E != NULL && ( ret = mbedtls_mpi_copy( &ctx->E, E ) ) != 0 ) ) | |
{ | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA + ret ); | |
} | |
if( N != NULL ) | |
ctx->len = mbedtls_mpi_size( &ctx->N ); | |
return( 0 ); | |
} | |
int mbedtls_rsa_import_raw( mbedtls_rsa_context *ctx, | |
unsigned char const *N, size_t N_len, | |
unsigned char const *P, size_t P_len, | |
unsigned char const *Q, size_t Q_len, | |
unsigned char const *D, size_t D_len, | |
unsigned char const *E, size_t E_len ) | |
{ | |
int ret = 0; | |
RSA_VALIDATE_RET( ctx != NULL ); | |
if( N != NULL ) | |
{ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &ctx->N, N, N_len ) ); | |
ctx->len = mbedtls_mpi_size( &ctx->N ); | |
} | |
if( P != NULL ) | |
MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &ctx->P, P, P_len ) ); | |
if( Q != NULL ) | |
MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &ctx->Q, Q, Q_len ) ); | |
if( D != NULL ) | |
MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &ctx->D, D, D_len ) ); | |
if( E != NULL ) | |
MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &ctx->E, E, E_len ) ); | |
cleanup: | |
if( ret != 0 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA + ret ); | |
return( 0 ); | |
} | |
/* | |
* Checks whether the context fields are set in such a way | |
* that the RSA primitives will be able to execute without error. | |
* It does *not* make guarantees for consistency of the parameters. | |
*/ | |
static int rsa_check_context( mbedtls_rsa_context const *ctx, int is_priv, | |
int blinding_needed ) | |
{ | |
#if !defined(MBEDTLS_RSA_NO_CRT) | |
/* blinding_needed is only used for NO_CRT to decide whether | |
* P,Q need to be present or not. */ | |
((void) blinding_needed); | |
#endif | |
if( ctx->len != mbedtls_mpi_size( &ctx->N ) || | |
ctx->len > MBEDTLS_MPI_MAX_SIZE ) | |
{ | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
} | |
/* | |
* 1. Modular exponentiation needs positive, odd moduli. | |
*/ | |
/* Modular exponentiation wrt. N is always used for | |
* RSA public key operations. */ | |
if( mbedtls_mpi_cmp_int( &ctx->N, 0 ) <= 0 || | |
mbedtls_mpi_get_bit( &ctx->N, 0 ) == 0 ) | |
{ | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
} | |
#if !defined(MBEDTLS_RSA_NO_CRT) | |
/* Modular exponentiation for P and Q is only | |
* used for private key operations and if CRT | |
* is used. */ | |
if( is_priv && | |
( mbedtls_mpi_cmp_int( &ctx->P, 0 ) <= 0 || | |
mbedtls_mpi_get_bit( &ctx->P, 0 ) == 0 || | |
mbedtls_mpi_cmp_int( &ctx->Q, 0 ) <= 0 || | |
mbedtls_mpi_get_bit( &ctx->Q, 0 ) == 0 ) ) | |
{ | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
} | |
#endif /* !MBEDTLS_RSA_NO_CRT */ | |
/* | |
* 2. Exponents must be positive | |
*/ | |
/* Always need E for public key operations */ | |
if( mbedtls_mpi_cmp_int( &ctx->E, 0 ) <= 0 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
#if defined(MBEDTLS_RSA_NO_CRT) | |
/* For private key operations, use D or DP & DQ | |
* as (unblinded) exponents. */ | |
if( is_priv && mbedtls_mpi_cmp_int( &ctx->D, 0 ) <= 0 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
#else | |
if( is_priv && | |
( mbedtls_mpi_cmp_int( &ctx->DP, 0 ) <= 0 || | |
mbedtls_mpi_cmp_int( &ctx->DQ, 0 ) <= 0 ) ) | |
{ | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
} | |
#endif /* MBEDTLS_RSA_NO_CRT */ | |
/* Blinding shouldn't make exponents negative either, | |
* so check that P, Q >= 1 if that hasn't yet been | |
* done as part of 1. */ | |
#if defined(MBEDTLS_RSA_NO_CRT) | |
if( is_priv && blinding_needed && | |
( mbedtls_mpi_cmp_int( &ctx->P, 0 ) <= 0 || | |
mbedtls_mpi_cmp_int( &ctx->Q, 0 ) <= 0 ) ) | |
{ | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
} | |
#endif | |
/* It wouldn't lead to an error if it wasn't satisfied, | |
* but check for QP >= 1 nonetheless. */ | |
#if !defined(MBEDTLS_RSA_NO_CRT) | |
if( is_priv && | |
mbedtls_mpi_cmp_int( &ctx->QP, 0 ) <= 0 ) | |
{ | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
} | |
#endif | |
return( 0 ); | |
} | |
int mbedtls_rsa_complete( mbedtls_rsa_context *ctx ) | |
{ | |
int ret = 0; | |
int have_N, have_P, have_Q, have_D, have_E; | |
int n_missing, pq_missing, d_missing, is_pub, is_priv; | |
RSA_VALIDATE_RET( ctx != NULL ); | |
have_N = ( mbedtls_mpi_cmp_int( &ctx->N, 0 ) != 0 ); | |
have_P = ( mbedtls_mpi_cmp_int( &ctx->P, 0 ) != 0 ); | |
have_Q = ( mbedtls_mpi_cmp_int( &ctx->Q, 0 ) != 0 ); | |
have_D = ( mbedtls_mpi_cmp_int( &ctx->D, 0 ) != 0 ); | |
have_E = ( mbedtls_mpi_cmp_int( &ctx->E, 0 ) != 0 ); | |
/* | |
* Check whether provided parameters are enough | |
* to deduce all others. The following incomplete | |
* parameter sets for private keys are supported: | |
* | |
* (1) P, Q missing. | |
* (2) D and potentially N missing. | |
* | |
*/ | |
n_missing = have_P && have_Q && have_D && have_E; | |
pq_missing = have_N && !have_P && !have_Q && have_D && have_E; | |
d_missing = have_P && have_Q && !have_D && have_E; | |
is_pub = have_N && !have_P && !have_Q && !have_D && have_E; | |
/* These three alternatives are mutually exclusive */ | |
is_priv = n_missing || pq_missing || d_missing; | |
if( !is_priv && !is_pub ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
/* | |
* Step 1: Deduce N if P, Q are provided. | |
*/ | |
if( !have_N && have_P && have_Q ) | |
{ | |
if( ( ret = mbedtls_mpi_mul_mpi( &ctx->N, &ctx->P, | |
&ctx->Q ) ) != 0 ) | |
{ | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA + ret ); | |
} | |
ctx->len = mbedtls_mpi_size( &ctx->N ); | |
} | |
/* | |
* Step 2: Deduce and verify all remaining core parameters. | |
*/ | |
if( pq_missing ) | |
{ | |
ret = mbedtls_rsa_deduce_primes( &ctx->N, &ctx->E, &ctx->D, | |
&ctx->P, &ctx->Q ); | |
if( ret != 0 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA + ret ); | |
} | |
else if( d_missing ) | |
{ | |
if( ( ret = mbedtls_rsa_deduce_private_exponent( &ctx->P, | |
&ctx->Q, | |
&ctx->E, | |
&ctx->D ) ) != 0 ) | |
{ | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA + ret ); | |
} | |
} | |
/* | |
* Step 3: Deduce all additional parameters specific | |
* to our current RSA implementation. | |
*/ | |
#if !defined(MBEDTLS_RSA_NO_CRT) | |
if( is_priv ) | |
{ | |
ret = mbedtls_rsa_deduce_crt( &ctx->P, &ctx->Q, &ctx->D, | |
&ctx->DP, &ctx->DQ, &ctx->QP ); | |
if( ret != 0 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA + ret ); | |
} | |
#endif /* MBEDTLS_RSA_NO_CRT */ | |
/* | |
* Step 3: Basic sanity checks | |
*/ | |
return( rsa_check_context( ctx, is_priv, 1 ) ); | |
} | |
int mbedtls_rsa_export_raw( const mbedtls_rsa_context *ctx, | |
unsigned char *N, size_t N_len, | |
unsigned char *P, size_t P_len, | |
unsigned char *Q, size_t Q_len, | |
unsigned char *D, size_t D_len, | |
unsigned char *E, size_t E_len ) | |
{ | |
int ret = 0; | |
int is_priv; | |
RSA_VALIDATE_RET( ctx != NULL ); | |
/* Check if key is private or public */ | |
is_priv = | |
mbedtls_mpi_cmp_int( &ctx->N, 0 ) != 0 && | |
mbedtls_mpi_cmp_int( &ctx->P, 0 ) != 0 && | |
mbedtls_mpi_cmp_int( &ctx->Q, 0 ) != 0 && | |
mbedtls_mpi_cmp_int( &ctx->D, 0 ) != 0 && | |
mbedtls_mpi_cmp_int( &ctx->E, 0 ) != 0; | |
if( !is_priv ) | |
{ | |
/* If we're trying to export private parameters for a public key, | |
* something must be wrong. */ | |
if( P != NULL || Q != NULL || D != NULL ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
} | |
if( N != NULL ) | |
MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->N, N, N_len ) ); | |
if( P != NULL ) | |
MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->P, P, P_len ) ); | |
if( Q != NULL ) | |
MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->Q, Q, Q_len ) ); | |
if( D != NULL ) | |
MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->D, D, D_len ) ); | |
if( E != NULL ) | |
MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->E, E, E_len ) ); | |
cleanup: | |
return( ret ); | |
} | |
int mbedtls_rsa_export( const mbedtls_rsa_context *ctx, | |
mbedtls_mpi *N, mbedtls_mpi *P, mbedtls_mpi *Q, | |
mbedtls_mpi *D, mbedtls_mpi *E ) | |
{ | |
int ret; | |
int is_priv; | |
RSA_VALIDATE_RET( ctx != NULL ); | |
/* Check if key is private or public */ | |
is_priv = | |
mbedtls_mpi_cmp_int( &ctx->N, 0 ) != 0 && | |
mbedtls_mpi_cmp_int( &ctx->P, 0 ) != 0 && | |
mbedtls_mpi_cmp_int( &ctx->Q, 0 ) != 0 && | |
mbedtls_mpi_cmp_int( &ctx->D, 0 ) != 0 && | |
mbedtls_mpi_cmp_int( &ctx->E, 0 ) != 0; | |
if( !is_priv ) | |
{ | |
/* If we're trying to export private parameters for a public key, | |
* something must be wrong. */ | |
if( P != NULL || Q != NULL || D != NULL ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
} | |
/* Export all requested core parameters. */ | |
if( ( N != NULL && ( ret = mbedtls_mpi_copy( N, &ctx->N ) ) != 0 ) || | |
( P != NULL && ( ret = mbedtls_mpi_copy( P, &ctx->P ) ) != 0 ) || | |
( Q != NULL && ( ret = mbedtls_mpi_copy( Q, &ctx->Q ) ) != 0 ) || | |
( D != NULL && ( ret = mbedtls_mpi_copy( D, &ctx->D ) ) != 0 ) || | |
( E != NULL && ( ret = mbedtls_mpi_copy( E, &ctx->E ) ) != 0 ) ) | |
{ | |
return( ret ); | |
} | |
return( 0 ); | |
} | |
/* | |
* Export CRT parameters | |
* This must also be implemented if CRT is not used, for being able to | |
* write DER encoded RSA keys. The helper function mbedtls_rsa_deduce_crt | |
* can be used in this case. | |
*/ | |
int mbedtls_rsa_export_crt( const mbedtls_rsa_context *ctx, | |
mbedtls_mpi *DP, mbedtls_mpi *DQ, mbedtls_mpi *QP ) | |
{ | |
int ret; | |
int is_priv; | |
RSA_VALIDATE_RET( ctx != NULL ); | |
/* Check if key is private or public */ | |
is_priv = | |
mbedtls_mpi_cmp_int( &ctx->N, 0 ) != 0 && | |
mbedtls_mpi_cmp_int( &ctx->P, 0 ) != 0 && | |
mbedtls_mpi_cmp_int( &ctx->Q, 0 ) != 0 && | |
mbedtls_mpi_cmp_int( &ctx->D, 0 ) != 0 && | |
mbedtls_mpi_cmp_int( &ctx->E, 0 ) != 0; | |
if( !is_priv ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
#if !defined(MBEDTLS_RSA_NO_CRT) | |
/* Export all requested blinding parameters. */ | |
if( ( DP != NULL && ( ret = mbedtls_mpi_copy( DP, &ctx->DP ) ) != 0 ) || | |
( DQ != NULL && ( ret = mbedtls_mpi_copy( DQ, &ctx->DQ ) ) != 0 ) || | |
( QP != NULL && ( ret = mbedtls_mpi_copy( QP, &ctx->QP ) ) != 0 ) ) | |
{ | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA + ret ); | |
} | |
#else | |
if( ( ret = mbedtls_rsa_deduce_crt( &ctx->P, &ctx->Q, &ctx->D, | |
DP, DQ, QP ) ) != 0 ) | |
{ | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA + ret ); | |
} | |
#endif | |
return( 0 ); | |
} | |
/* | |
* Initialize an RSA context | |
*/ | |
void mbedtls_rsa_init( mbedtls_rsa_context *ctx, | |
int padding, | |
int hash_id ) | |
{ | |
RSA_VALIDATE( ctx != NULL ); | |
RSA_VALIDATE( padding == MBEDTLS_RSA_PKCS_V15 || | |
padding == MBEDTLS_RSA_PKCS_V21 ); | |
memset( ctx, 0, sizeof( mbedtls_rsa_context ) ); | |
mbedtls_rsa_set_padding( ctx, padding, hash_id ); | |
#if defined(MBEDTLS_THREADING_C) | |
mbedtls_mutex_init( &ctx->mutex ); | |
#endif | |
} | |
/* | |
* Set padding for an existing RSA context | |
*/ | |
void mbedtls_rsa_set_padding( mbedtls_rsa_context *ctx, int padding, | |
int hash_id ) | |
{ | |
RSA_VALIDATE( ctx != NULL ); | |
RSA_VALIDATE( padding == MBEDTLS_RSA_PKCS_V15 || | |
padding == MBEDTLS_RSA_PKCS_V21 ); | |
ctx->padding = padding; | |
ctx->hash_id = hash_id; | |
} | |
/* | |
* Get length in bytes of RSA modulus | |
*/ | |
size_t mbedtls_rsa_get_len( const mbedtls_rsa_context *ctx ) | |
{ | |
return( ctx->len ); | |
} | |
#if defined(MBEDTLS_GENPRIME) | |
/* | |
* Generate an RSA keypair | |
* | |
* This generation method follows the RSA key pair generation procedure of | |
* FIPS 186-4 if 2^16 < exponent < 2^256 and nbits = 2048 or nbits = 3072. | |
*/ | |
int mbedtls_rsa_gen_key( mbedtls_rsa_context *ctx, | |
int (*f_rng)(void *, unsigned char *, size_t), | |
void *p_rng, | |
unsigned int nbits, int exponent ) | |
{ | |
int ret; | |
mbedtls_mpi H, G, L; | |
int prime_quality = 0; | |
RSA_VALIDATE_RET( ctx != NULL ); | |
RSA_VALIDATE_RET( f_rng != NULL ); | |
if( nbits < 128 || exponent < 3 || nbits % 2 != 0 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
/* | |
* If the modulus is 1024 bit long or shorter, then the security strength of | |
* the RSA algorithm is less than or equal to 80 bits and therefore an error | |
* rate of 2^-80 is sufficient. | |
*/ | |
if( nbits > 1024 ) | |
prime_quality = MBEDTLS_MPI_GEN_PRIME_FLAG_LOW_ERR; | |
mbedtls_mpi_init( &H ); | |
mbedtls_mpi_init( &G ); | |
mbedtls_mpi_init( &L ); | |
/* | |
* find primes P and Q with Q < P so that: | |
* 1. |P-Q| > 2^( nbits / 2 - 100 ) | |
* 2. GCD( E, (P-1)*(Q-1) ) == 1 | |
* 3. E^-1 mod LCM(P-1, Q-1) > 2^( nbits / 2 ) | |
*/ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &ctx->E, exponent ) ); | |
do | |
{ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_gen_prime( &ctx->P, nbits >> 1, | |
prime_quality, f_rng, p_rng ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_gen_prime( &ctx->Q, nbits >> 1, | |
prime_quality, f_rng, p_rng ) ); | |
/* make sure the difference between p and q is not too small (FIPS 186-4 §B.3.3 step 5.4) */ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &H, &ctx->P, &ctx->Q ) ); | |
if( mbedtls_mpi_bitlen( &H ) <= ( ( nbits >= 200 ) ? ( ( nbits >> 1 ) - 99 ) : 0 ) ) | |
continue; | |
/* not required by any standards, but some users rely on the fact that P > Q */ | |
if( H.s < 0 ) | |
mbedtls_mpi_swap( &ctx->P, &ctx->Q ); | |
/* Temporarily replace P,Q by P-1, Q-1 */ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &ctx->P, &ctx->P, 1 ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &ctx->Q, &ctx->Q, 1 ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &H, &ctx->P, &ctx->Q ) ); | |
/* check GCD( E, (P-1)*(Q-1) ) == 1 (FIPS 186-4 §B.3.1 criterion 2(a)) */ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( &G, &ctx->E, &H ) ); | |
if( mbedtls_mpi_cmp_int( &G, 1 ) != 0 ) | |
continue; | |
/* compute smallest possible D = E^-1 mod LCM(P-1, Q-1) (FIPS 186-4 §B.3.1 criterion 3(b)) */ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( &G, &ctx->P, &ctx->Q ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_div_mpi( &L, NULL, &H, &G ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &ctx->D, &ctx->E, &L ) ); | |
if( mbedtls_mpi_bitlen( &ctx->D ) <= ( ( nbits + 1 ) / 2 ) ) // (FIPS 186-4 §B.3.1 criterion 3(a)) | |
continue; | |
break; | |
} | |
while( 1 ); | |
/* Restore P,Q */ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_add_int( &ctx->P, &ctx->P, 1 ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_add_int( &ctx->Q, &ctx->Q, 1 ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->N, &ctx->P, &ctx->Q ) ); | |
ctx->len = mbedtls_mpi_size( &ctx->N ); | |
#if !defined(MBEDTLS_RSA_NO_CRT) | |
/* | |
* DP = D mod (P - 1) | |
* DQ = D mod (Q - 1) | |
* QP = Q^-1 mod P | |
*/ | |
MBEDTLS_MPI_CHK( mbedtls_rsa_deduce_crt( &ctx->P, &ctx->Q, &ctx->D, | |
&ctx->DP, &ctx->DQ, &ctx->QP ) ); | |
#endif /* MBEDTLS_RSA_NO_CRT */ | |
/* Double-check */ | |
MBEDTLS_MPI_CHK( mbedtls_rsa_check_privkey( ctx ) ); | |
cleanup: | |
mbedtls_mpi_free( &H ); | |
mbedtls_mpi_free( &G ); | |
mbedtls_mpi_free( &L ); | |
if( ret != 0 ) | |
{ | |
mbedtls_rsa_free( ctx ); | |
return( MBEDTLS_ERR_RSA_KEY_GEN_FAILED + ret ); | |
} | |
return( 0 ); | |
} | |
#endif /* MBEDTLS_GENPRIME */ | |
/* | |
* Check a public RSA key | |
*/ | |
int mbedtls_rsa_check_pubkey( const mbedtls_rsa_context *ctx ) | |
{ | |
RSA_VALIDATE_RET( ctx != NULL ); | |
if( rsa_check_context( ctx, 0 /* public */, 0 /* no blinding */ ) != 0 ) | |
return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED ); | |
if( mbedtls_mpi_bitlen( &ctx->N ) < 128 ) | |
{ | |
return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED ); | |
} | |
if( mbedtls_mpi_get_bit( &ctx->E, 0 ) == 0 || | |
mbedtls_mpi_bitlen( &ctx->E ) < 2 || | |
mbedtls_mpi_cmp_mpi( &ctx->E, &ctx->N ) >= 0 ) | |
{ | |
return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED ); | |
} | |
return( 0 ); | |
} | |
/* | |
* Check for the consistency of all fields in an RSA private key context | |
*/ | |
int mbedtls_rsa_check_privkey( const mbedtls_rsa_context *ctx ) | |
{ | |
RSA_VALIDATE_RET( ctx != NULL ); | |
if( mbedtls_rsa_check_pubkey( ctx ) != 0 || | |
rsa_check_context( ctx, 1 /* private */, 1 /* blinding */ ) != 0 ) | |
{ | |
return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED ); | |
} | |
if( mbedtls_rsa_validate_params( &ctx->N, &ctx->P, &ctx->Q, | |
&ctx->D, &ctx->E, NULL, NULL ) != 0 ) | |
{ | |
return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED ); | |
} | |
#if !defined(MBEDTLS_RSA_NO_CRT) | |
else if( mbedtls_rsa_validate_crt( &ctx->P, &ctx->Q, &ctx->D, | |
&ctx->DP, &ctx->DQ, &ctx->QP ) != 0 ) | |
{ | |
return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED ); | |
} | |
#endif | |
return( 0 ); | |
} | |
/* | |
* Check if contexts holding a public and private key match | |
*/ | |
int mbedtls_rsa_check_pub_priv( const mbedtls_rsa_context *pub, | |
const mbedtls_rsa_context *prv ) | |
{ | |
RSA_VALIDATE_RET( pub != NULL ); | |
RSA_VALIDATE_RET( prv != NULL ); | |
if( mbedtls_rsa_check_pubkey( pub ) != 0 || | |
mbedtls_rsa_check_privkey( prv ) != 0 ) | |
{ | |
return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED ); | |
} | |
if( mbedtls_mpi_cmp_mpi( &pub->N, &prv->N ) != 0 || | |
mbedtls_mpi_cmp_mpi( &pub->E, &prv->E ) != 0 ) | |
{ | |
return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED ); | |
} | |
return( 0 ); | |
} | |
/* | |
* Do an RSA public key operation | |
*/ | |
int mbedtls_rsa_public( mbedtls_rsa_context *ctx, | |
const unsigned char *input, | |
unsigned char *output ) | |
{ | |
int ret; | |
size_t olen; | |
mbedtls_mpi T; | |
RSA_VALIDATE_RET( ctx != NULL ); | |
RSA_VALIDATE_RET( input != NULL ); | |
RSA_VALIDATE_RET( output != NULL ); | |
if( rsa_check_context( ctx, 0 /* public */, 0 /* no blinding */ ) ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
mbedtls_mpi_init( &T ); | |
#if defined(MBEDTLS_THREADING_C) | |
if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 ) | |
return( ret ); | |
#endif | |
MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &T, input, ctx->len ) ); | |
if( mbedtls_mpi_cmp_mpi( &T, &ctx->N ) >= 0 ) | |
{ | |
ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA; | |
goto cleanup; | |
} | |
olen = ctx->len; | |
MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &T, &T, &ctx->E, &ctx->N, &ctx->RN ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &T, output, olen ) ); | |
cleanup: | |
#if defined(MBEDTLS_THREADING_C) | |
if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 ) | |
return( MBEDTLS_ERR_THREADING_MUTEX_ERROR ); | |
#endif | |
mbedtls_mpi_free( &T ); | |
if( ret != 0 ) | |
return( MBEDTLS_ERR_RSA_PUBLIC_FAILED + ret ); | |
return( 0 ); | |
} | |
/* | |
* Generate or update blinding values, see section 10 of: | |
* KOCHER, Paul C. Timing attacks on implementations of Diffie-Hellman, RSA, | |
* DSS, and other systems. In : Advances in Cryptology-CRYPTO'96. Springer | |
* Berlin Heidelberg, 1996. p. 104-113. | |
*/ | |
static int rsa_prepare_blinding( mbedtls_rsa_context *ctx, | |
int (*f_rng)(void *, unsigned char *, size_t), void *p_rng ) | |
{ | |
int ret, count = 0; | |
if( ctx->Vf.p != NULL ) | |
{ | |
/* We already have blinding values, just update them by squaring */ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vi, &ctx->Vi, &ctx->Vi ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vi, &ctx->Vi, &ctx->N ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vf, &ctx->Vf, &ctx->Vf ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vf, &ctx->Vf, &ctx->N ) ); | |
goto cleanup; | |
} | |
/* Unblinding value: Vf = random number, invertible mod N */ | |
do { | |
if( count++ > 10 ) | |
return( MBEDTLS_ERR_RSA_RNG_FAILED ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->Vf, ctx->len - 1, f_rng, p_rng ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( &ctx->Vi, &ctx->Vf, &ctx->N ) ); | |
} while( mbedtls_mpi_cmp_int( &ctx->Vi, 1 ) != 0 ); | |
/* Blinding value: Vi = Vf^(-e) mod N */ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &ctx->Vi, &ctx->Vf, &ctx->N ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->Vi, &ctx->Vi, &ctx->E, &ctx->N, &ctx->RN ) ); | |
cleanup: | |
return( ret ); | |
} | |
/* | |
* Exponent blinding supposed to prevent side-channel attacks using multiple | |
* traces of measurements to recover the RSA key. The more collisions are there, | |
* the more bits of the key can be recovered. See [3]. | |
* | |
* Collecting n collisions with m bit long blinding value requires 2^(m-m/n) | |
* observations on avarage. | |
* | |
* For example with 28 byte blinding to achieve 2 collisions the adversary has | |
* to make 2^112 observations on avarage. | |
* | |
* (With the currently (as of 2017 April) known best algorithms breaking 2048 | |
* bit RSA requires approximately as much time as trying out 2^112 random keys. | |
* Thus in this sense with 28 byte blinding the security is not reduced by | |
* side-channel attacks like the one in [3]) | |
* | |
* This countermeasure does not help if the key recovery is possible with a | |
* single trace. | |
*/ | |
#define RSA_EXPONENT_BLINDING 28 | |
/* | |
* Do an RSA private key operation | |
*/ | |
int mbedtls_rsa_private( mbedtls_rsa_context *ctx, | |
int (*f_rng)(void *, unsigned char *, size_t), | |
void *p_rng, | |
const unsigned char *input, | |
unsigned char *output ) | |
{ | |
int ret; | |
size_t olen; | |
/* Temporary holding the result */ | |
mbedtls_mpi T; | |
/* Temporaries holding P-1, Q-1 and the | |
* exponent blinding factor, respectively. */ | |
mbedtls_mpi P1, Q1, R; | |
#if !defined(MBEDTLS_RSA_NO_CRT) | |
/* Temporaries holding the results mod p resp. mod q. */ | |
mbedtls_mpi TP, TQ; | |
/* Temporaries holding the blinded exponents for | |
* the mod p resp. mod q computation (if used). */ | |
mbedtls_mpi DP_blind, DQ_blind; | |
/* Pointers to actual exponents to be used - either the unblinded | |
* or the blinded ones, depending on the presence of a PRNG. */ | |
mbedtls_mpi *DP = &ctx->DP; | |
mbedtls_mpi *DQ = &ctx->DQ; | |
#else | |
/* Temporary holding the blinded exponent (if used). */ | |
mbedtls_mpi D_blind; | |
/* Pointer to actual exponent to be used - either the unblinded | |
* or the blinded one, depending on the presence of a PRNG. */ | |
mbedtls_mpi *D = &ctx->D; | |
#endif /* MBEDTLS_RSA_NO_CRT */ | |
/* Temporaries holding the initial input and the double | |
* checked result; should be the same in the end. */ | |
mbedtls_mpi I, C; | |
RSA_VALIDATE_RET( ctx != NULL ); | |
RSA_VALIDATE_RET( input != NULL ); | |
RSA_VALIDATE_RET( output != NULL ); | |
if( rsa_check_context( ctx, 1 /* private key checks */, | |
f_rng != NULL /* blinding y/n */ ) != 0 ) | |
{ | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
} | |
#if defined(MBEDTLS_THREADING_C) | |
if( ( ret = mbedtls_mutex_lock( &ctx->mutex ) ) != 0 ) | |
return( ret ); | |
#endif | |
/* MPI Initialization */ | |
mbedtls_mpi_init( &T ); | |
mbedtls_mpi_init( &P1 ); | |
mbedtls_mpi_init( &Q1 ); | |
mbedtls_mpi_init( &R ); | |
if( f_rng != NULL ) | |
{ | |
#if defined(MBEDTLS_RSA_NO_CRT) | |
mbedtls_mpi_init( &D_blind ); | |
#else | |
mbedtls_mpi_init( &DP_blind ); | |
mbedtls_mpi_init( &DQ_blind ); | |
#endif | |
} | |
#if !defined(MBEDTLS_RSA_NO_CRT) | |
mbedtls_mpi_init( &TP ); mbedtls_mpi_init( &TQ ); | |
#endif | |
mbedtls_mpi_init( &I ); | |
mbedtls_mpi_init( &C ); | |
/* End of MPI initialization */ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( &T, input, ctx->len ) ); | |
if( mbedtls_mpi_cmp_mpi( &T, &ctx->N ) >= 0 ) | |
{ | |
ret = MBEDTLS_ERR_MPI_BAD_INPUT_DATA; | |
goto cleanup; | |
} | |
MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &I, &T ) ); | |
if( f_rng != NULL ) | |
{ | |
/* | |
* Blinding | |
* T = T * Vi mod N | |
*/ | |
MBEDTLS_MPI_CHK( rsa_prepare_blinding( ctx, f_rng, p_rng ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T, &T, &ctx->Vi ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &T, &T, &ctx->N ) ); | |
/* | |
* Exponent blinding | |
*/ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &P1, &ctx->P, 1 ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &Q1, &ctx->Q, 1 ) ); | |
#if defined(MBEDTLS_RSA_NO_CRT) | |
/* | |
* D_blind = ( P - 1 ) * ( Q - 1 ) * R + D | |
*/ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &R, RSA_EXPONENT_BLINDING, | |
f_rng, p_rng ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &D_blind, &P1, &Q1 ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &D_blind, &D_blind, &R ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &D_blind, &D_blind, &ctx->D ) ); | |
D = &D_blind; | |
#else | |
/* | |
* DP_blind = ( P - 1 ) * R + DP | |
*/ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &R, RSA_EXPONENT_BLINDING, | |
f_rng, p_rng ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &DP_blind, &P1, &R ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &DP_blind, &DP_blind, | |
&ctx->DP ) ); | |
DP = &DP_blind; | |
/* | |
* DQ_blind = ( Q - 1 ) * R + DQ | |
*/ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &R, RSA_EXPONENT_BLINDING, | |
f_rng, p_rng ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &DQ_blind, &Q1, &R ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &DQ_blind, &DQ_blind, | |
&ctx->DQ ) ); | |
DQ = &DQ_blind; | |
#endif /* MBEDTLS_RSA_NO_CRT */ | |
} | |
#if defined(MBEDTLS_RSA_NO_CRT) | |
MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &T, &T, D, &ctx->N, &ctx->RN ) ); | |
#else | |
/* | |
* Faster decryption using the CRT | |
* | |
* TP = input ^ dP mod P | |
* TQ = input ^ dQ mod Q | |
*/ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &TP, &T, DP, &ctx->P, &ctx->RP ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &TQ, &T, DQ, &ctx->Q, &ctx->RQ ) ); | |
/* | |
* T = (TP - TQ) * (Q^-1 mod P) mod P | |
*/ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &T, &TP, &TQ ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &TP, &T, &ctx->QP ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &T, &TP, &ctx->P ) ); | |
/* | |
* T = TQ + T * Q | |
*/ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &TP, &T, &ctx->Q ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &T, &TQ, &TP ) ); | |
#endif /* MBEDTLS_RSA_NO_CRT */ | |
if( f_rng != NULL ) | |
{ | |
/* | |
* Unblind | |
* T = T * Vf mod N | |
*/ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T, &T, &ctx->Vf ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &T, &T, &ctx->N ) ); | |
} | |
/* Verify the result to prevent glitching attacks. */ | |
MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &C, &T, &ctx->E, | |
&ctx->N, &ctx->RN ) ); | |
if( mbedtls_mpi_cmp_mpi( &C, &I ) != 0 ) | |
{ | |
ret = MBEDTLS_ERR_RSA_VERIFY_FAILED; | |
goto cleanup; | |
} | |
olen = ctx->len; | |
MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &T, output, olen ) ); | |
cleanup: | |
#if defined(MBEDTLS_THREADING_C) | |
if( mbedtls_mutex_unlock( &ctx->mutex ) != 0 ) | |
return( MBEDTLS_ERR_THREADING_MUTEX_ERROR ); | |
#endif | |
mbedtls_mpi_free( &P1 ); | |
mbedtls_mpi_free( &Q1 ); | |
mbedtls_mpi_free( &R ); | |
if( f_rng != NULL ) | |
{ | |
#if defined(MBEDTLS_RSA_NO_CRT) | |
mbedtls_mpi_free( &D_blind ); | |
#else | |
mbedtls_mpi_free( &DP_blind ); | |
mbedtls_mpi_free( &DQ_blind ); | |
#endif | |
} | |
mbedtls_mpi_free( &T ); | |
#if !defined(MBEDTLS_RSA_NO_CRT) | |
mbedtls_mpi_free( &TP ); mbedtls_mpi_free( &TQ ); | |
#endif | |
mbedtls_mpi_free( &C ); | |
mbedtls_mpi_free( &I ); | |
if( ret != 0 ) | |
return( MBEDTLS_ERR_RSA_PRIVATE_FAILED + ret ); | |
return( 0 ); | |
} | |
#if defined(MBEDTLS_PKCS1_V21) | |
/** | |
* Generate and apply the MGF1 operation (from PKCS#1 v2.1) to a buffer. | |
* | |
* \param dst buffer to mask | |
* \param dlen length of destination buffer | |
* \param src source of the mask generation | |
* \param slen length of the source buffer | |
* \param md_ctx message digest context to use | |
*/ | |
static int mgf_mask( unsigned char *dst, size_t dlen, unsigned char *src, | |
size_t slen, mbedtls_md_context_t *md_ctx ) | |
{ | |
unsigned char mask[MBEDTLS_MD_MAX_SIZE]; | |
unsigned char counter[4]; | |
unsigned char *p; | |
unsigned int hlen; | |
size_t i, use_len; | |
int ret = 0; | |
memset( mask, 0, MBEDTLS_MD_MAX_SIZE ); | |
memset( counter, 0, 4 ); | |
hlen = mbedtls_md_get_size( md_ctx->md_info ); | |
/* Generate and apply dbMask */ | |
p = dst; | |
while( dlen > 0 ) | |
{ | |
use_len = hlen; | |
if( dlen < hlen ) | |
use_len = dlen; | |
if( ( ret = mbedtls_md_starts( md_ctx ) ) != 0 ) | |
goto exit; | |
if( ( ret = mbedtls_md_update( md_ctx, src, slen ) ) != 0 ) | |
goto exit; | |
if( ( ret = mbedtls_md_update( md_ctx, counter, 4 ) ) != 0 ) | |
goto exit; | |
if( ( ret = mbedtls_md_finish( md_ctx, mask ) ) != 0 ) | |
goto exit; | |
for( i = 0; i < use_len; ++i ) | |
*p++ ^= mask[i]; | |
counter[3]++; | |
dlen -= use_len; | |
} | |
exit: | |
mbedtls_platform_zeroize( mask, sizeof( mask ) ); | |
return( ret ); | |
} | |
#endif /* MBEDTLS_PKCS1_V21 */ | |
#if defined(MBEDTLS_PKCS1_V21) | |
/* | |
* Implementation of the PKCS#1 v2.1 RSAES-OAEP-ENCRYPT function | |
*/ | |
int mbedtls_rsa_rsaes_oaep_encrypt( mbedtls_rsa_context *ctx, | |
int (*f_rng)(void *, unsigned char *, size_t), | |
void *p_rng, | |
int mode, | |
const unsigned char *label, size_t label_len, | |
size_t ilen, | |
const unsigned char *input, | |
unsigned char *output ) | |
{ | |
size_t olen; | |
int ret; | |
unsigned char *p = output; | |
unsigned int hlen; | |
const mbedtls_md_info_t *md_info; | |
mbedtls_md_context_t md_ctx; | |
RSA_VALIDATE_RET( ctx != NULL ); | |
RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE || | |
mode == MBEDTLS_RSA_PUBLIC ); | |
RSA_VALIDATE_RET( output != NULL ); | |
RSA_VALIDATE_RET( ilen == 0 || input != NULL ); | |
RSA_VALIDATE_RET( label_len == 0 || label != NULL ); | |
if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V21 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
if( f_rng == NULL ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
md_info = mbedtls_md_info_from_type( (mbedtls_md_type_t) ctx->hash_id ); | |
if( md_info == NULL ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
olen = ctx->len; | |
hlen = mbedtls_md_get_size( md_info ); | |
/* first comparison checks for overflow */ | |
if( ilen + 2 * hlen + 2 < ilen || olen < ilen + 2 * hlen + 2 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
memset( output, 0, olen ); | |
*p++ = 0; | |
/* Generate a random octet string seed */ | |
if( ( ret = f_rng( p_rng, p, hlen ) ) != 0 ) | |
return( MBEDTLS_ERR_RSA_RNG_FAILED + ret ); | |
p += hlen; | |
/* Construct DB */ | |
if( ( ret = mbedtls_md( md_info, label, label_len, p ) ) != 0 ) | |
return( ret ); | |
p += hlen; | |
p += olen - 2 * hlen - 2 - ilen; | |
*p++ = 1; | |
if( ilen != 0 ) | |
memcpy( p, input, ilen ); | |
mbedtls_md_init( &md_ctx ); | |
if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 ) | |
goto exit; | |
/* maskedDB: Apply dbMask to DB */ | |
if( ( ret = mgf_mask( output + hlen + 1, olen - hlen - 1, output + 1, hlen, | |
&md_ctx ) ) != 0 ) | |
goto exit; | |
/* maskedSeed: Apply seedMask to seed */ | |
if( ( ret = mgf_mask( output + 1, hlen, output + hlen + 1, olen - hlen - 1, | |
&md_ctx ) ) != 0 ) | |
goto exit; | |
exit: | |
mbedtls_md_free( &md_ctx ); | |
if( ret != 0 ) | |
return( ret ); | |
return( ( mode == MBEDTLS_RSA_PUBLIC ) | |
? mbedtls_rsa_public( ctx, output, output ) | |
: mbedtls_rsa_private( ctx, f_rng, p_rng, output, output ) ); | |
} | |
#endif /* MBEDTLS_PKCS1_V21 */ | |
#if defined(MBEDTLS_PKCS1_V15) | |
/* | |
* Implementation of the PKCS#1 v2.1 RSAES-PKCS1-V1_5-ENCRYPT function | |
*/ | |
int mbedtls_rsa_rsaes_pkcs1_v15_encrypt( mbedtls_rsa_context *ctx, | |
int (*f_rng)(void *, unsigned char *, size_t), | |
void *p_rng, | |
int mode, size_t ilen, | |
const unsigned char *input, | |
unsigned char *output ) | |
{ | |
size_t nb_pad, olen; | |
int ret; | |
unsigned char *p = output; | |
RSA_VALIDATE_RET( ctx != NULL ); | |
RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE || | |
mode == MBEDTLS_RSA_PUBLIC ); | |
RSA_VALIDATE_RET( output != NULL ); | |
RSA_VALIDATE_RET( ilen == 0 || input != NULL ); | |
if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V15 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
olen = ctx->len; | |
/* first comparison checks for overflow */ | |
if( ilen + 11 < ilen || olen < ilen + 11 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
nb_pad = olen - 3 - ilen; | |
*p++ = 0; | |
if( mode == MBEDTLS_RSA_PUBLIC ) | |
{ | |
if( f_rng == NULL ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
*p++ = MBEDTLS_RSA_CRYPT; | |
while( nb_pad-- > 0 ) | |
{ | |
int rng_dl = 100; | |
do { | |
ret = f_rng( p_rng, p, 1 ); | |
} while( *p == 0 && --rng_dl && ret == 0 ); | |
/* Check if RNG failed to generate data */ | |
if( rng_dl == 0 || ret != 0 ) | |
return( MBEDTLS_ERR_RSA_RNG_FAILED + ret ); | |
p++; | |
} | |
} | |
else | |
{ | |
*p++ = MBEDTLS_RSA_SIGN; | |
while( nb_pad-- > 0 ) | |
*p++ = 0xFF; | |
} | |
*p++ = 0; | |
if( ilen != 0 ) | |
memcpy( p, input, ilen ); | |
return( ( mode == MBEDTLS_RSA_PUBLIC ) | |
? mbedtls_rsa_public( ctx, output, output ) | |
: mbedtls_rsa_private( ctx, f_rng, p_rng, output, output ) ); | |
} | |
#endif /* MBEDTLS_PKCS1_V15 */ | |
/* | |
* Add the message padding, then do an RSA operation | |
*/ | |
int mbedtls_rsa_pkcs1_encrypt( mbedtls_rsa_context *ctx, | |
int (*f_rng)(void *, unsigned char *, size_t), | |
void *p_rng, | |
int mode, size_t ilen, | |
const unsigned char *input, | |
unsigned char *output ) | |
{ | |
RSA_VALIDATE_RET( ctx != NULL ); | |
RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE || | |
mode == MBEDTLS_RSA_PUBLIC ); | |
RSA_VALIDATE_RET( output != NULL ); | |
RSA_VALIDATE_RET( ilen == 0 || input != NULL ); | |
switch( ctx->padding ) | |
{ | |
#if defined(MBEDTLS_PKCS1_V15) | |
case MBEDTLS_RSA_PKCS_V15: | |
return mbedtls_rsa_rsaes_pkcs1_v15_encrypt( ctx, f_rng, p_rng, mode, ilen, | |
input, output ); | |
#endif | |
#if defined(MBEDTLS_PKCS1_V21) | |
case MBEDTLS_RSA_PKCS_V21: | |
return mbedtls_rsa_rsaes_oaep_encrypt( ctx, f_rng, p_rng, mode, NULL, 0, | |
ilen, input, output ); | |
#endif | |
default: | |
return( MBEDTLS_ERR_RSA_INVALID_PADDING ); | |
} | |
} | |
#if defined(MBEDTLS_PKCS1_V21) | |
/* | |
* Implementation of the PKCS#1 v2.1 RSAES-OAEP-DECRYPT function | |
*/ | |
int mbedtls_rsa_rsaes_oaep_decrypt( mbedtls_rsa_context *ctx, | |
int (*f_rng)(void *, unsigned char *, size_t), | |
void *p_rng, | |
int mode, | |
const unsigned char *label, size_t label_len, | |
size_t *olen, | |
const unsigned char *input, | |
unsigned char *output, | |
size_t output_max_len ) | |
{ | |
int ret; | |
size_t ilen, i, pad_len; | |
unsigned char *p, bad, pad_done; | |
unsigned char buf[MBEDTLS_MPI_MAX_SIZE]; | |
unsigned char lhash[MBEDTLS_MD_MAX_SIZE]; | |
unsigned int hlen; | |
const mbedtls_md_info_t *md_info; | |
mbedtls_md_context_t md_ctx; | |
RSA_VALIDATE_RET( ctx != NULL ); | |
RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE || | |
mode == MBEDTLS_RSA_PUBLIC ); | |
RSA_VALIDATE_RET( output_max_len == 0 || output != NULL ); | |
RSA_VALIDATE_RET( label_len == 0 || label != NULL ); | |
RSA_VALIDATE_RET( input != NULL ); | |
RSA_VALIDATE_RET( olen != NULL ); | |
/* | |
* Parameters sanity checks | |
*/ | |
if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V21 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
ilen = ctx->len; | |
if( ilen < 16 || ilen > sizeof( buf ) ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
md_info = mbedtls_md_info_from_type( (mbedtls_md_type_t) ctx->hash_id ); | |
if( md_info == NULL ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
hlen = mbedtls_md_get_size( md_info ); | |
// checking for integer underflow | |
if( 2 * hlen + 2 > ilen ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
/* | |
* RSA operation | |
*/ | |
ret = ( mode == MBEDTLS_RSA_PUBLIC ) | |
? mbedtls_rsa_public( ctx, input, buf ) | |
: mbedtls_rsa_private( ctx, f_rng, p_rng, input, buf ); | |
if( ret != 0 ) | |
goto cleanup; | |
/* | |
* Unmask data and generate lHash | |
*/ | |
mbedtls_md_init( &md_ctx ); | |
if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 ) | |
{ | |
mbedtls_md_free( &md_ctx ); | |
goto cleanup; | |
} | |
/* seed: Apply seedMask to maskedSeed */ | |
if( ( ret = mgf_mask( buf + 1, hlen, buf + hlen + 1, ilen - hlen - 1, | |
&md_ctx ) ) != 0 || | |
/* DB: Apply dbMask to maskedDB */ | |
( ret = mgf_mask( buf + hlen + 1, ilen - hlen - 1, buf + 1, hlen, | |
&md_ctx ) ) != 0 ) | |
{ | |
mbedtls_md_free( &md_ctx ); | |
goto cleanup; | |
} | |
mbedtls_md_free( &md_ctx ); | |
/* Generate lHash */ | |
if( ( ret = mbedtls_md( md_info, label, label_len, lhash ) ) != 0 ) | |
goto cleanup; | |
/* | |
* Check contents, in "constant-time" | |
*/ | |
p = buf; | |
bad = 0; | |
bad |= *p++; /* First byte must be 0 */ | |
p += hlen; /* Skip seed */ | |
/* Check lHash */ | |
for( i = 0; i < hlen; i++ ) | |
bad |= lhash[i] ^ *p++; | |
/* Get zero-padding len, but always read till end of buffer | |
* (minus one, for the 01 byte) */ | |
pad_len = 0; | |
pad_done = 0; | |
for( i = 0; i < ilen - 2 * hlen - 2; i++ ) | |
{ | |
pad_done |= p[i]; | |
pad_len += ((pad_done | (unsigned char)-pad_done) >> 7) ^ 1; | |
} | |
p += pad_len; | |
bad |= *p++ ^ 0x01; | |
/* | |
* The only information "leaked" is whether the padding was correct or not | |
* (eg, no data is copied if it was not correct). This meets the | |
* recommendations in PKCS#1 v2.2: an opponent cannot distinguish between | |
* the different error conditions. | |
*/ | |
if( bad != 0 ) | |
{ | |
ret = MBEDTLS_ERR_RSA_INVALID_PADDING; | |
goto cleanup; | |
} | |
if( ilen - ( p - buf ) > output_max_len ) | |
{ | |
ret = MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE; | |
goto cleanup; | |
} | |
*olen = ilen - (p - buf); | |
if( *olen != 0 ) | |
memcpy( output, p, *olen ); | |
ret = 0; | |
cleanup: | |
mbedtls_platform_zeroize( buf, sizeof( buf ) ); | |
mbedtls_platform_zeroize( lhash, sizeof( lhash ) ); | |
return( ret ); | |
} | |
#endif /* MBEDTLS_PKCS1_V21 */ | |
#if defined(MBEDTLS_PKCS1_V15) | |
/** Turn zero-or-nonzero into zero-or-all-bits-one, without branches. | |
* | |
* \param value The value to analyze. | |
* \return Zero if \p value is zero, otherwise all-bits-one. | |
*/ | |
static unsigned all_or_nothing_int( unsigned value ) | |
{ | |
/* MSVC has a warning about unary minus on unsigned, but this is | |
* well-defined and precisely what we want to do here */ | |
#if defined(_MSC_VER) | |
#pragma warning( push ) | |
#pragma warning( disable : 4146 ) | |
#endif | |
return( - ( ( value | - value ) >> ( sizeof( value ) * 8 - 1 ) ) ); | |
#if defined(_MSC_VER) | |
#pragma warning( pop ) | |
#endif | |
} | |
/** Check whether a size is out of bounds, without branches. | |
* | |
* This is equivalent to `size > max`, but is likely to be compiled to | |
* to code using bitwise operation rather than a branch. | |
* | |
* \param size Size to check. | |
* \param max Maximum desired value for \p size. | |
* \return \c 0 if `size <= max`. | |
* \return \c 1 if `size > max`. | |
*/ | |
static unsigned size_greater_than( size_t size, size_t max ) | |
{ | |
/* Return the sign bit (1 for negative) of (max - size). */ | |
return( ( max - size ) >> ( sizeof( size_t ) * 8 - 1 ) ); | |
} | |
/** Choose between two integer values, without branches. | |
* | |
* This is equivalent to `cond ? if1 : if0`, but is likely to be compiled | |
* to code using bitwise operation rather than a branch. | |
* | |
* \param cond Condition to test. | |
* \param if1 Value to use if \p cond is nonzero. | |
* \param if0 Value to use if \p cond is zero. | |
* \return \c if1 if \p cond is nonzero, otherwise \c if0. | |
*/ | |
static unsigned if_int( unsigned cond, unsigned if1, unsigned if0 ) | |
{ | |
unsigned mask = all_or_nothing_int( cond ); | |
return( ( mask & if1 ) | (~mask & if0 ) ); | |
} | |
/** Shift some data towards the left inside a buffer without leaking | |
* the length of the data through side channels. | |
* | |
* `mem_move_to_left(start, total, offset)` is functionally equivalent to | |
* ``` | |
* memmove(start, start + offset, total - offset); | |
* memset(start + offset, 0, total - offset); | |
* ``` | |
* but it strives to use a memory access pattern (and thus total timing) | |
* that does not depend on \p offset. This timing independence comes at | |
* the expense of performance. | |
* | |
* \param start Pointer to the start of the buffer. | |
* \param total Total size of the buffer. | |
* \param offset Offset from which to copy \p total - \p offset bytes. | |
*/ | |
static void mem_move_to_left( void *start, | |
size_t total, | |
size_t offset ) | |
{ | |
volatile unsigned char *buf = start; | |
size_t i, n; | |
if( total == 0 ) | |
return; | |
for( i = 0; i < total; i++ ) | |
{ | |
unsigned no_op = size_greater_than( total - offset, i ); | |
/* The first `total - offset` passes are a no-op. The last | |
* `offset` passes shift the data one byte to the left and | |
* zero out the last byte. */ | |
for( n = 0; n < total - 1; n++ ) | |
{ | |
unsigned char current = buf[n]; | |
unsigned char next = buf[n+1]; | |
buf[n] = if_int( no_op, current, next ); | |
} | |
buf[total-1] = if_int( no_op, buf[total-1], 0 ); | |
} | |
} | |
/* | |
* Implementation of the PKCS#1 v2.1 RSAES-PKCS1-V1_5-DECRYPT function | |
*/ | |
int mbedtls_rsa_rsaes_pkcs1_v15_decrypt( mbedtls_rsa_context *ctx, | |
int (*f_rng)(void *, unsigned char *, size_t), | |
void *p_rng, | |
int mode, size_t *olen, | |
const unsigned char *input, | |
unsigned char *output, | |
size_t output_max_len ) | |
{ | |
int ret; | |
size_t ilen, i, plaintext_max_size; | |
unsigned char buf[MBEDTLS_MPI_MAX_SIZE]; | |
/* The following variables take sensitive values: their value must | |
* not leak into the observable behavior of the function other than | |
* the designated outputs (output, olen, return value). Otherwise | |
* this would open the execution of the function to | |
* side-channel-based variants of the Bleichenbacher padding oracle | |
* attack. Potential side channels include overall timing, memory | |
* access patterns (especially visible to an adversary who has access | |
* to a shared memory cache), and branches (especially visible to | |
* an adversary who has access to a shared code cache or to a shared | |
* branch predictor). */ | |
size_t pad_count = 0; | |
unsigned bad = 0; | |
unsigned char pad_done = 0; | |
size_t plaintext_size = 0; | |
unsigned output_too_large; | |
RSA_VALIDATE_RET( ctx != NULL ); | |
RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE || | |
mode == MBEDTLS_RSA_PUBLIC ); | |
RSA_VALIDATE_RET( output_max_len == 0 || output != NULL ); | |
RSA_VALIDATE_RET( input != NULL ); | |
RSA_VALIDATE_RET( olen != NULL ); | |
ilen = ctx->len; | |
plaintext_max_size = ( output_max_len > ilen - 11 ? | |
ilen - 11 : | |
output_max_len ); | |
if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V15 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
if( ilen < 16 || ilen > sizeof( buf ) ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
ret = ( mode == MBEDTLS_RSA_PUBLIC ) | |
? mbedtls_rsa_public( ctx, input, buf ) | |
: mbedtls_rsa_private( ctx, f_rng, p_rng, input, buf ); | |
if( ret != 0 ) | |
goto cleanup; | |
/* Check and get padding length in constant time and constant | |
* memory trace. The first byte must be 0. */ | |
bad |= buf[0]; | |
if( mode == MBEDTLS_RSA_PRIVATE ) | |
{ | |
/* Decode EME-PKCS1-v1_5 padding: 0x00 || 0x02 || PS || 0x00 | |
* where PS must be at least 8 nonzero bytes. */ | |
bad |= buf[1] ^ MBEDTLS_RSA_CRYPT; | |
/* Read the whole buffer. Set pad_done to nonzero if we find | |
* the 0x00 byte and remember the padding length in pad_count. */ | |
for( i = 2; i < ilen; i++ ) | |
{ | |
pad_done |= ((buf[i] | (unsigned char)-buf[i]) >> 7) ^ 1; | |
pad_count += ((pad_done | (unsigned char)-pad_done) >> 7) ^ 1; | |
} | |
} | |
else | |
{ | |
/* Decode EMSA-PKCS1-v1_5 padding: 0x00 || 0x01 || PS || 0x00 | |
* where PS must be at least 8 bytes with the value 0xFF. */ | |
bad |= buf[1] ^ MBEDTLS_RSA_SIGN; | |
/* Read the whole buffer. Set pad_done to nonzero if we find | |
* the 0x00 byte and remember the padding length in pad_count. | |
* If there's a non-0xff byte in the padding, the padding is bad. */ | |
for( i = 2; i < ilen; i++ ) | |
{ | |
pad_done |= if_int( buf[i], 0, 1 ); | |
pad_count += if_int( pad_done, 0, 1 ); | |
bad |= if_int( pad_done, 0, buf[i] ^ 0xFF ); | |
} | |
} | |
/* If pad_done is still zero, there's no data, only unfinished padding. */ | |
bad |= if_int( pad_done, 0, 1 ); | |
/* There must be at least 8 bytes of padding. */ | |
bad |= size_greater_than( 8, pad_count ); | |
/* If the padding is valid, set plaintext_size to the number of | |
* remaining bytes after stripping the padding. If the padding | |
* is invalid, avoid leaking this fact through the size of the | |
* output: use the maximum message size that fits in the output | |
* buffer. Do it without branches to avoid leaking the padding | |
* validity through timing. RSA keys are small enough that all the | |
* size_t values involved fit in unsigned int. */ | |
plaintext_size = if_int( bad, | |
(unsigned) plaintext_max_size, | |
(unsigned) ( ilen - pad_count - 3 ) ); | |
/* Set output_too_large to 0 if the plaintext fits in the output | |
* buffer and to 1 otherwise. */ | |
output_too_large = size_greater_than( plaintext_size, | |
plaintext_max_size ); | |
/* Set ret without branches to avoid timing attacks. Return: | |
* - INVALID_PADDING if the padding is bad (bad != 0). | |
* - OUTPUT_TOO_LARGE if the padding is good but the decrypted | |
* plaintext does not fit in the output buffer. | |
* - 0 if the padding is correct. */ | |
ret = - (int) if_int( bad, - MBEDTLS_ERR_RSA_INVALID_PADDING, | |
if_int( output_too_large, - MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE, | |
0 ) ); | |
/* If the padding is bad or the plaintext is too large, zero the | |
* data that we're about to copy to the output buffer. | |
* We need to copy the same amount of data | |
* from the same buffer whether the padding is good or not to | |
* avoid leaking the padding validity through overall timing or | |
* through memory or cache access patterns. */ | |
bad = all_or_nothing_int( bad | output_too_large ); | |
for( i = 11; i < ilen; i++ ) | |
buf[i] &= ~bad; | |
/* If the plaintext is too large, truncate it to the buffer size. | |
* Copy anyway to avoid revealing the length through timing, because | |
* revealing the length is as bad as revealing the padding validity | |
* for a Bleichenbacher attack. */ | |
plaintext_size = if_int( output_too_large, | |
(unsigned) plaintext_max_size, | |
(unsigned) plaintext_size ); | |
/* Move the plaintext to the leftmost position where it can start in | |
* the working buffer, i.e. make it start plaintext_max_size from | |
* the end of the buffer. Do this with a memory access trace that | |
* does not depend on the plaintext size. After this move, the | |
* starting location of the plaintext is no longer sensitive | |
* information. */ | |
mem_move_to_left( buf + ilen - plaintext_max_size, | |
plaintext_max_size, | |
plaintext_max_size - plaintext_size ); | |
/* Finally copy the decrypted plaintext plus trailing zeros into the output | |
* buffer. If output_max_len is 0, then output may be an invalid pointer | |
* and the result of memcpy() would be undefined; prevent undefined | |
* behavior making sure to depend only on output_max_len (the size of the | |
* user-provided output buffer), which is independent from plaintext | |
* length, validity of padding, success of the decryption, and other | |
* secrets. */ | |
if( output_max_len != 0 ) | |
memcpy( output, buf + ilen - plaintext_max_size, plaintext_max_size ); | |
/* Report the amount of data we copied to the output buffer. In case | |
* of errors (bad padding or output too large), the value of *olen | |
* when this function returns is not specified. Making it equivalent | |
* to the good case limits the risks of leaking the padding validity. */ | |
*olen = plaintext_size; | |
cleanup: | |
mbedtls_platform_zeroize( buf, sizeof( buf ) ); | |
return( ret ); | |
} | |
#endif /* MBEDTLS_PKCS1_V15 */ | |
/* | |
* Do an RSA operation, then remove the message padding | |
*/ | |
int mbedtls_rsa_pkcs1_decrypt( mbedtls_rsa_context *ctx, | |
int (*f_rng)(void *, unsigned char *, size_t), | |
void *p_rng, | |
int mode, size_t *olen, | |
const unsigned char *input, | |
unsigned char *output, | |
size_t output_max_len) | |
{ | |
RSA_VALIDATE_RET( ctx != NULL ); | |
RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE || | |
mode == MBEDTLS_RSA_PUBLIC ); | |
RSA_VALIDATE_RET( output_max_len == 0 || output != NULL ); | |
RSA_VALIDATE_RET( input != NULL ); | |
RSA_VALIDATE_RET( olen != NULL ); | |
switch( ctx->padding ) | |
{ | |
#if defined(MBEDTLS_PKCS1_V15) | |
case MBEDTLS_RSA_PKCS_V15: | |
return mbedtls_rsa_rsaes_pkcs1_v15_decrypt( ctx, f_rng, p_rng, mode, olen, | |
input, output, output_max_len ); | |
#endif | |
#if defined(MBEDTLS_PKCS1_V21) | |
case MBEDTLS_RSA_PKCS_V21: | |
return mbedtls_rsa_rsaes_oaep_decrypt( ctx, f_rng, p_rng, mode, NULL, 0, | |
olen, input, output, | |
output_max_len ); | |
#endif | |
default: | |
return( MBEDTLS_ERR_RSA_INVALID_PADDING ); | |
} | |
} | |
#if defined(MBEDTLS_PKCS1_V21) | |
/* | |
* Implementation of the PKCS#1 v2.1 RSASSA-PSS-SIGN function | |
*/ | |
int mbedtls_rsa_rsassa_pss_sign( mbedtls_rsa_context *ctx, | |
int (*f_rng)(void *, unsigned char *, size_t), | |
void *p_rng, | |
int mode, | |
mbedtls_md_type_t md_alg, | |
unsigned int hashlen, | |
const unsigned char *hash, | |
unsigned char *sig ) | |
{ | |
size_t olen; | |
unsigned char *p = sig; | |
unsigned char salt[MBEDTLS_MD_MAX_SIZE]; | |
size_t slen, min_slen, hlen, offset = 0; | |
int ret; | |
size_t msb; | |
const mbedtls_md_info_t *md_info; | |
mbedtls_md_context_t md_ctx; | |
RSA_VALIDATE_RET( ctx != NULL ); | |
RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE || | |
mode == MBEDTLS_RSA_PUBLIC ); | |
RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE && | |
hashlen == 0 ) || | |
hash != NULL ); | |
RSA_VALIDATE_RET( sig != NULL ); | |
if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V21 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
if( f_rng == NULL ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
olen = ctx->len; | |
if( md_alg != MBEDTLS_MD_NONE ) | |
{ | |
/* Gather length of hash to sign */ | |
md_info = mbedtls_md_info_from_type( md_alg ); | |
if( md_info == NULL ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
hashlen = mbedtls_md_get_size( md_info ); | |
} | |
md_info = mbedtls_md_info_from_type( (mbedtls_md_type_t) ctx->hash_id ); | |
if( md_info == NULL ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
hlen = mbedtls_md_get_size( md_info ); | |
/* Calculate the largest possible salt length. Normally this is the hash | |
* length, which is the maximum length the salt can have. If there is not | |
* enough room, use the maximum salt length that fits. The constraint is | |
* that the hash length plus the salt length plus 2 bytes must be at most | |
* the key length. This complies with FIPS 186-4 §5.5 (e) and RFC 8017 | |
* (PKCS#1 v2.2) §9.1.1 step 3. */ | |
min_slen = hlen - 2; | |
if( olen < hlen + min_slen + 2 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
else if( olen >= hlen + hlen + 2 ) | |
slen = hlen; | |
else | |
slen = olen - hlen - 2; | |
memset( sig, 0, olen ); | |
/* Generate salt of length slen */ | |
if( ( ret = f_rng( p_rng, salt, slen ) ) != 0 ) | |
return( MBEDTLS_ERR_RSA_RNG_FAILED + ret ); | |
/* Note: EMSA-PSS encoding is over the length of N - 1 bits */ | |
msb = mbedtls_mpi_bitlen( &ctx->N ) - 1; | |
p += olen - hlen - slen - 2; | |
*p++ = 0x01; | |
memcpy( p, salt, slen ); | |
p += slen; | |
mbedtls_md_init( &md_ctx ); | |
if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 ) | |
goto exit; | |
/* Generate H = Hash( M' ) */ | |
if( ( ret = mbedtls_md_starts( &md_ctx ) ) != 0 ) | |
goto exit; | |
if( ( ret = mbedtls_md_update( &md_ctx, p, 8 ) ) != 0 ) | |
goto exit; | |
if( ( ret = mbedtls_md_update( &md_ctx, hash, hashlen ) ) != 0 ) | |
goto exit; | |
if( ( ret = mbedtls_md_update( &md_ctx, salt, slen ) ) != 0 ) | |
goto exit; | |
if( ( ret = mbedtls_md_finish( &md_ctx, p ) ) != 0 ) | |
goto exit; | |
/* Compensate for boundary condition when applying mask */ | |
if( msb % 8 == 0 ) | |
offset = 1; | |
/* maskedDB: Apply dbMask to DB */ | |
if( ( ret = mgf_mask( sig + offset, olen - hlen - 1 - offset, p, hlen, | |
&md_ctx ) ) != 0 ) | |
goto exit; | |
msb = mbedtls_mpi_bitlen( &ctx->N ) - 1; | |
sig[0] &= 0xFF >> ( olen * 8 - msb ); | |
p += hlen; | |
*p++ = 0xBC; | |
mbedtls_platform_zeroize( salt, sizeof( salt ) ); | |
exit: | |
mbedtls_md_free( &md_ctx ); | |
if( ret != 0 ) | |
return( ret ); | |
return( ( mode == MBEDTLS_RSA_PUBLIC ) | |
? mbedtls_rsa_public( ctx, sig, sig ) | |
: mbedtls_rsa_private( ctx, f_rng, p_rng, sig, sig ) ); | |
} | |
#endif /* MBEDTLS_PKCS1_V21 */ | |
#if defined(MBEDTLS_PKCS1_V15) | |
/* | |
* Implementation of the PKCS#1 v2.1 RSASSA-PKCS1-V1_5-SIGN function | |
*/ | |
/* Construct a PKCS v1.5 encoding of a hashed message | |
* | |
* This is used both for signature generation and verification. | |
* | |
* Parameters: | |
* - md_alg: Identifies the hash algorithm used to generate the given hash; | |
* MBEDTLS_MD_NONE if raw data is signed. | |
* - hashlen: Length of hash in case hashlen is MBEDTLS_MD_NONE. | |
* - hash: Buffer containing the hashed message or the raw data. | |
* - dst_len: Length of the encoded message. | |
* - dst: Buffer to hold the encoded message. | |
* | |
* Assumptions: | |
* - hash has size hashlen if md_alg == MBEDTLS_MD_NONE. | |
* - hash has size corresponding to md_alg if md_alg != MBEDTLS_MD_NONE. | |
* - dst points to a buffer of size at least dst_len. | |
* | |
*/ | |
static int rsa_rsassa_pkcs1_v15_encode( mbedtls_md_type_t md_alg, | |
unsigned int hashlen, | |
const unsigned char *hash, | |
size_t dst_len, | |
unsigned char *dst ) | |
{ | |
size_t oid_size = 0; | |
size_t nb_pad = dst_len; | |
unsigned char *p = dst; | |
const char *oid = NULL; | |
/* Are we signing hashed or raw data? */ | |
if( md_alg != MBEDTLS_MD_NONE ) | |
{ | |
const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type( md_alg ); | |
if( md_info == NULL ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
if( mbedtls_oid_get_oid_by_md( md_alg, &oid, &oid_size ) != 0 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
hashlen = mbedtls_md_get_size( md_info ); | |
/* Double-check that 8 + hashlen + oid_size can be used as a | |
* 1-byte ASN.1 length encoding and that there's no overflow. */ | |
if( 8 + hashlen + oid_size >= 0x80 || | |
10 + hashlen < hashlen || | |
10 + hashlen + oid_size < 10 + hashlen ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
/* | |
* Static bounds check: | |
* - Need 10 bytes for five tag-length pairs. | |
* (Insist on 1-byte length encodings to protect against variants of | |
* Bleichenbacher's forgery attack against lax PKCS#1v1.5 verification) | |
* - Need hashlen bytes for hash | |
* - Need oid_size bytes for hash alg OID. | |
*/ | |
if( nb_pad < 10 + hashlen + oid_size ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
nb_pad -= 10 + hashlen + oid_size; | |
} | |
else | |
{ | |
if( nb_pad < hashlen ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
nb_pad -= hashlen; | |
} | |
/* Need space for signature header and padding delimiter (3 bytes), | |
* and 8 bytes for the minimal padding */ | |
if( nb_pad < 3 + 8 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
nb_pad -= 3; | |
/* Now nb_pad is the amount of memory to be filled | |
* with padding, and at least 8 bytes long. */ | |
/* Write signature header and padding */ | |
*p++ = 0; | |
*p++ = MBEDTLS_RSA_SIGN; | |
memset( p, 0xFF, nb_pad ); | |
p += nb_pad; | |
*p++ = 0; | |
/* Are we signing raw data? */ | |
if( md_alg == MBEDTLS_MD_NONE ) | |
{ | |
memcpy( p, hash, hashlen ); | |
return( 0 ); | |
} | |
/* Signing hashed data, add corresponding ASN.1 structure | |
* | |
* DigestInfo ::= SEQUENCE { | |
* digestAlgorithm DigestAlgorithmIdentifier, | |
* digest Digest } | |
* DigestAlgorithmIdentifier ::= AlgorithmIdentifier | |
* Digest ::= OCTET STRING | |
* | |
* Schematic: | |
* TAG-SEQ + LEN [ TAG-SEQ + LEN [ TAG-OID + LEN [ OID ] | |
* TAG-NULL + LEN [ NULL ] ] | |
* TAG-OCTET + LEN [ HASH ] ] | |
*/ | |
*p++ = MBEDTLS_ASN1_SEQUENCE | MBEDTLS_ASN1_CONSTRUCTED; | |
*p++ = (unsigned char)( 0x08 + oid_size + hashlen ); | |
*p++ = MBEDTLS_ASN1_SEQUENCE | MBEDTLS_ASN1_CONSTRUCTED; | |
*p++ = (unsigned char)( 0x04 + oid_size ); | |
*p++ = MBEDTLS_ASN1_OID; | |
*p++ = (unsigned char) oid_size; | |
memcpy( p, oid, oid_size ); | |
p += oid_size; | |
*p++ = MBEDTLS_ASN1_NULL; | |
*p++ = 0x00; | |
*p++ = MBEDTLS_ASN1_OCTET_STRING; | |
*p++ = (unsigned char) hashlen; | |
memcpy( p, hash, hashlen ); | |
p += hashlen; | |
/* Just a sanity-check, should be automatic | |
* after the initial bounds check. */ | |
if( p != dst + dst_len ) | |
{ | |
mbedtls_platform_zeroize( dst, dst_len ); | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
} | |
return( 0 ); | |
} | |
/* | |
* Do an RSA operation to sign the message digest | |
*/ | |
int mbedtls_rsa_rsassa_pkcs1_v15_sign( mbedtls_rsa_context *ctx, | |
int (*f_rng)(void *, unsigned char *, size_t), | |
void *p_rng, | |
int mode, | |
mbedtls_md_type_t md_alg, | |
unsigned int hashlen, | |
const unsigned char *hash, | |
unsigned char *sig ) | |
{ | |
int ret; | |
unsigned char *sig_try = NULL, *verif = NULL; | |
RSA_VALIDATE_RET( ctx != NULL ); | |
RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE || | |
mode == MBEDTLS_RSA_PUBLIC ); | |
RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE && | |
hashlen == 0 ) || | |
hash != NULL ); | |
RSA_VALIDATE_RET( sig != NULL ); | |
if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V15 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
/* | |
* Prepare PKCS1-v1.5 encoding (padding and hash identifier) | |
*/ | |
if( ( ret = rsa_rsassa_pkcs1_v15_encode( md_alg, hashlen, hash, | |
ctx->len, sig ) ) != 0 ) | |
return( ret ); | |
/* | |
* Call respective RSA primitive | |
*/ | |
if( mode == MBEDTLS_RSA_PUBLIC ) | |
{ | |
/* Skip verification on a public key operation */ | |
return( mbedtls_rsa_public( ctx, sig, sig ) ); | |
} | |
/* Private key operation | |
* | |
* In order to prevent Lenstra's attack, make the signature in a | |
* temporary buffer and check it before returning it. | |
*/ | |
sig_try = mbedtls_calloc( 1, ctx->len ); | |
if( sig_try == NULL ) | |
return( MBEDTLS_ERR_MPI_ALLOC_FAILED ); | |
verif = mbedtls_calloc( 1, ctx->len ); | |
if( verif == NULL ) | |
{ | |
mbedtls_free( sig_try ); | |
return( MBEDTLS_ERR_MPI_ALLOC_FAILED ); | |
} | |
MBEDTLS_MPI_CHK( mbedtls_rsa_private( ctx, f_rng, p_rng, sig, sig_try ) ); | |
MBEDTLS_MPI_CHK( mbedtls_rsa_public( ctx, sig_try, verif ) ); | |
if( mbedtls_safer_memcmp( verif, sig, ctx->len ) != 0 ) | |
{ | |
ret = MBEDTLS_ERR_RSA_PRIVATE_FAILED; | |
goto cleanup; | |
} | |
memcpy( sig, sig_try, ctx->len ); | |
cleanup: | |
mbedtls_free( sig_try ); | |
mbedtls_free( verif ); | |
return( ret ); | |
} | |
#endif /* MBEDTLS_PKCS1_V15 */ | |
/* | |
* Do an RSA operation to sign the message digest | |
*/ | |
int mbedtls_rsa_pkcs1_sign( mbedtls_rsa_context *ctx, | |
int (*f_rng)(void *, unsigned char *, size_t), | |
void *p_rng, | |
int mode, | |
mbedtls_md_type_t md_alg, | |
unsigned int hashlen, | |
const unsigned char *hash, | |
unsigned char *sig ) | |
{ | |
RSA_VALIDATE_RET( ctx != NULL ); | |
RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE || | |
mode == MBEDTLS_RSA_PUBLIC ); | |
RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE && | |
hashlen == 0 ) || | |
hash != NULL ); | |
RSA_VALIDATE_RET( sig != NULL ); | |
switch( ctx->padding ) | |
{ | |
#if defined(MBEDTLS_PKCS1_V15) | |
case MBEDTLS_RSA_PKCS_V15: | |
return mbedtls_rsa_rsassa_pkcs1_v15_sign( ctx, f_rng, p_rng, mode, md_alg, | |
hashlen, hash, sig ); | |
#endif | |
#if defined(MBEDTLS_PKCS1_V21) | |
case MBEDTLS_RSA_PKCS_V21: | |
return mbedtls_rsa_rsassa_pss_sign( ctx, f_rng, p_rng, mode, md_alg, | |
hashlen, hash, sig ); | |
#endif | |
default: | |
return( MBEDTLS_ERR_RSA_INVALID_PADDING ); | |
} | |
} | |
#if defined(MBEDTLS_PKCS1_V21) | |
/* | |
* Implementation of the PKCS#1 v2.1 RSASSA-PSS-VERIFY function | |
*/ | |
int mbedtls_rsa_rsassa_pss_verify_ext( mbedtls_rsa_context *ctx, | |
int (*f_rng)(void *, unsigned char *, size_t), | |
void *p_rng, | |
int mode, | |
mbedtls_md_type_t md_alg, | |
unsigned int hashlen, | |
const unsigned char *hash, | |
mbedtls_md_type_t mgf1_hash_id, | |
int expected_salt_len, | |
const unsigned char *sig ) | |
{ | |
int ret; | |
size_t siglen; | |
unsigned char *p; | |
unsigned char *hash_start; | |
unsigned char result[MBEDTLS_MD_MAX_SIZE]; | |
unsigned char zeros[8]; | |
unsigned int hlen; | |
size_t observed_salt_len, msb; | |
const mbedtls_md_info_t *md_info; | |
mbedtls_md_context_t md_ctx; | |
unsigned char buf[MBEDTLS_MPI_MAX_SIZE]; | |
RSA_VALIDATE_RET( ctx != NULL ); | |
RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE || | |
mode == MBEDTLS_RSA_PUBLIC ); | |
RSA_VALIDATE_RET( sig != NULL ); | |
RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE && | |
hashlen == 0 ) || | |
hash != NULL ); | |
if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V21 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
siglen = ctx->len; | |
if( siglen < 16 || siglen > sizeof( buf ) ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
ret = ( mode == MBEDTLS_RSA_PUBLIC ) | |
? mbedtls_rsa_public( ctx, sig, buf ) | |
: mbedtls_rsa_private( ctx, f_rng, p_rng, sig, buf ); | |
if( ret != 0 ) | |
return( ret ); | |
p = buf; | |
if( buf[siglen - 1] != 0xBC ) | |
return( MBEDTLS_ERR_RSA_INVALID_PADDING ); | |
if( md_alg != MBEDTLS_MD_NONE ) | |
{ | |
/* Gather length of hash to sign */ | |
md_info = mbedtls_md_info_from_type( md_alg ); | |
if( md_info == NULL ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
hashlen = mbedtls_md_get_size( md_info ); | |
} | |
md_info = mbedtls_md_info_from_type( mgf1_hash_id ); | |
if( md_info == NULL ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
hlen = mbedtls_md_get_size( md_info ); | |
memset( zeros, 0, 8 ); | |
/* | |
* Note: EMSA-PSS verification is over the length of N - 1 bits | |
*/ | |
msb = mbedtls_mpi_bitlen( &ctx->N ) - 1; | |
if( buf[0] >> ( 8 - siglen * 8 + msb ) ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
/* Compensate for boundary condition when applying mask */ | |
if( msb % 8 == 0 ) | |
{ | |
p++; | |
siglen -= 1; | |
} | |
if( siglen < hlen + 2 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
hash_start = p + siglen - hlen - 1; | |
mbedtls_md_init( &md_ctx ); | |
if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 ) | |
goto exit; | |
ret = mgf_mask( p, siglen - hlen - 1, hash_start, hlen, &md_ctx ); | |
if( ret != 0 ) | |
goto exit; | |
buf[0] &= 0xFF >> ( siglen * 8 - msb ); | |
while( p < hash_start - 1 && *p == 0 ) | |
p++; | |
if( *p++ != 0x01 ) | |
{ | |
ret = MBEDTLS_ERR_RSA_INVALID_PADDING; | |
goto exit; | |
} | |
observed_salt_len = hash_start - p; | |
if( expected_salt_len != MBEDTLS_RSA_SALT_LEN_ANY && | |
observed_salt_len != (size_t) expected_salt_len ) | |
{ | |
ret = MBEDTLS_ERR_RSA_INVALID_PADDING; | |
goto exit; | |
} | |
/* | |
* Generate H = Hash( M' ) | |
*/ | |
ret = mbedtls_md_starts( &md_ctx ); | |
if ( ret != 0 ) | |
goto exit; | |
ret = mbedtls_md_update( &md_ctx, zeros, 8 ); | |
if ( ret != 0 ) | |
goto exit; | |
ret = mbedtls_md_update( &md_ctx, hash, hashlen ); | |
if ( ret != 0 ) | |
goto exit; | |
ret = mbedtls_md_update( &md_ctx, p, observed_salt_len ); | |
if ( ret != 0 ) | |
goto exit; | |
ret = mbedtls_md_finish( &md_ctx, result ); | |
if ( ret != 0 ) | |
goto exit; | |
if( memcmp( hash_start, result, hlen ) != 0 ) | |
{ | |
ret = MBEDTLS_ERR_RSA_VERIFY_FAILED; | |
goto exit; | |
} | |
exit: | |
mbedtls_md_free( &md_ctx ); | |
return( ret ); | |
} | |
/* | |
* Simplified PKCS#1 v2.1 RSASSA-PSS-VERIFY function | |
*/ | |
int mbedtls_rsa_rsassa_pss_verify( mbedtls_rsa_context *ctx, | |
int (*f_rng)(void *, unsigned char *, size_t), | |
void *p_rng, | |
int mode, | |
mbedtls_md_type_t md_alg, | |
unsigned int hashlen, | |
const unsigned char *hash, | |
const unsigned char *sig ) | |
{ | |
mbedtls_md_type_t mgf1_hash_id; | |
RSA_VALIDATE_RET( ctx != NULL ); | |
RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE || | |
mode == MBEDTLS_RSA_PUBLIC ); | |
RSA_VALIDATE_RET( sig != NULL ); | |
RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE && | |
hashlen == 0 ) || | |
hash != NULL ); | |
mgf1_hash_id = ( ctx->hash_id != MBEDTLS_MD_NONE ) | |
? (mbedtls_md_type_t) ctx->hash_id | |
: md_alg; | |
return( mbedtls_rsa_rsassa_pss_verify_ext( ctx, f_rng, p_rng, mode, | |
md_alg, hashlen, hash, | |
mgf1_hash_id, MBEDTLS_RSA_SALT_LEN_ANY, | |
sig ) ); | |
} | |
#endif /* MBEDTLS_PKCS1_V21 */ | |
#if defined(MBEDTLS_PKCS1_V15) | |
/* | |
* Implementation of the PKCS#1 v2.1 RSASSA-PKCS1-v1_5-VERIFY function | |
*/ | |
int mbedtls_rsa_rsassa_pkcs1_v15_verify( mbedtls_rsa_context *ctx, | |
int (*f_rng)(void *, unsigned char *, size_t), | |
void *p_rng, | |
int mode, | |
mbedtls_md_type_t md_alg, | |
unsigned int hashlen, | |
const unsigned char *hash, | |
const unsigned char *sig ) | |
{ | |
int ret = 0; | |
size_t sig_len; | |
unsigned char *encoded = NULL, *encoded_expected = NULL; | |
RSA_VALIDATE_RET( ctx != NULL ); | |
RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE || | |
mode == MBEDTLS_RSA_PUBLIC ); | |
RSA_VALIDATE_RET( sig != NULL ); | |
RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE && | |
hashlen == 0 ) || | |
hash != NULL ); | |
sig_len = ctx->len; | |
if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V15 ) | |
return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); | |
/* | |
* Prepare expected PKCS1 v1.5 encoding of hash. | |
*/ | |
if( ( encoded = mbedtls_calloc( 1, sig_len ) ) == NULL || | |
( encoded_expected = mbedtls_calloc( 1, sig_len ) ) == NULL ) | |
{ | |
ret = MBEDTLS_ERR_MPI_ALLOC_FAILED; | |
goto cleanup; | |
} | |
if( ( ret = rsa_rsassa_pkcs1_v15_encode( md_alg, hashlen, hash, sig_len, | |
encoded_expected ) ) != 0 ) | |
goto cleanup; | |
/* | |
* Apply RSA primitive to get what should be PKCS1 encoded hash. | |
*/ | |
ret = ( mode == MBEDTLS_RSA_PUBLIC ) | |
? mbedtls_rsa_public( ctx, sig, encoded ) | |
: mbedtls_rsa_private( ctx, f_rng, p_rng, sig, encoded ); | |
if( ret != 0 ) | |
goto cleanup; | |
/* | |
* Compare | |
*/ | |
if( ( ret = mbedtls_safer_memcmp( encoded, encoded_expected, | |
sig_len ) ) != 0 ) | |
{ | |
ret = MBEDTLS_ERR_RSA_VERIFY_FAILED; | |
goto cleanup; | |
} | |
cleanup: | |
if( encoded != NULL ) | |
{ | |
mbedtls_platform_zeroize( encoded, sig_len ); | |
mbedtls_free( encoded ); | |
} | |
if( encoded_expected != NULL ) | |
{ | |
mbedtls_platform_zeroize( encoded_expected, sig_len ); | |
mbedtls_free( encoded_expected ); | |
} | |
return( ret ); | |
} | |
#endif /* MBEDTLS_PKCS1_V15 */ | |
/* | |
* Do an RSA operation and check the message digest | |
*/ | |
int mbedtls_rsa_pkcs1_verify( mbedtls_rsa_context *ctx, | |
int (*f_rng)(void *, unsigned char *, size_t), | |
void *p_rng, | |
int mode, | |
mbedtls_md_type_t md_alg, | |
unsigned int hashlen, | |
const unsigned char *hash, | |
const unsigned char *sig ) | |
{ | |
RSA_VALIDATE_RET( ctx != NULL ); | |
RSA_VALIDATE_RET( mode == MBEDTLS_RSA_PRIVATE || | |
mode == MBEDTLS_RSA_PUBLIC ); | |
RSA_VALIDATE_RET( sig != NULL ); | |
RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE && | |
hashlen == 0 ) || | |
hash != NULL ); | |
switch( ctx->padding ) | |
{ | |
#if defined(MBEDTLS_PKCS1_V15) | |
case MBEDTLS_RSA_PKCS_V15: | |
return mbedtls_rsa_rsassa_pkcs1_v15_verify( ctx, f_rng, p_rng, mode, md_alg, | |
hashlen, hash, sig ); | |
#endif | |
#if defined(MBEDTLS_PKCS1_V21) | |
case MBEDTLS_RSA_PKCS_V21: | |
return mbedtls_rsa_rsassa_pss_verify( ctx, f_rng, p_rng, mode, md_alg, | |
hashlen, hash, sig ); | |
#endif | |
default: | |
return( MBEDTLS_ERR_RSA_INVALID_PADDING ); | |
} | |
} | |
/* | |
* Copy the components of an RSA key | |
*/ | |
int mbedtls_rsa_copy( mbedtls_rsa_context *dst, const mbedtls_rsa_context *src ) | |
{ | |
int ret; | |
RSA_VALIDATE_RET( dst != NULL ); | |
RSA_VALIDATE_RET( src != NULL ); | |
dst->ver = src->ver; | |
dst->len = src->len; | |
MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->N, &src->N ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->E, &src->E ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->D, &src->D ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->P, &src->P ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->Q, &src->Q ) ); | |
#if !defined(MBEDTLS_RSA_NO_CRT) | |
MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->DP, &src->DP ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->DQ, &src->DQ ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->QP, &src->QP ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->RP, &src->RP ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->RQ, &src->RQ ) ); | |
#endif | |
MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->RN, &src->RN ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->Vi, &src->Vi ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->Vf, &src->Vf ) ); | |
dst->padding = src->padding; | |
dst->hash_id = src->hash_id; | |
cleanup: | |
if( ret != 0 ) | |
mbedtls_rsa_free( dst ); | |
return( ret ); | |
} | |
/* | |
* Free the components of an RSA key | |
*/ | |
void mbedtls_rsa_free( mbedtls_rsa_context *ctx ) | |
{ | |
if( ctx == NULL ) | |
return; | |
mbedtls_mpi_free( &ctx->Vi ); | |
mbedtls_mpi_free( &ctx->Vf ); | |
mbedtls_mpi_free( &ctx->RN ); | |
mbedtls_mpi_free( &ctx->D ); | |
mbedtls_mpi_free( &ctx->Q ); | |
mbedtls_mpi_free( &ctx->P ); | |
mbedtls_mpi_free( &ctx->E ); | |
mbedtls_mpi_free( &ctx->N ); | |
#if !defined(MBEDTLS_RSA_NO_CRT) | |
mbedtls_mpi_free( &ctx->RQ ); | |
mbedtls_mpi_free( &ctx->RP ); | |
mbedtls_mpi_free( &ctx->QP ); | |
mbedtls_mpi_free( &ctx->DQ ); | |
mbedtls_mpi_free( &ctx->DP ); | |
#endif /* MBEDTLS_RSA_NO_CRT */ | |
#if defined(MBEDTLS_THREADING_C) | |
mbedtls_mutex_free( &ctx->mutex ); | |
#endif | |
} | |
#endif /* !MBEDTLS_RSA_ALT */ | |
#if defined(MBEDTLS_SELF_TEST) | |
#include "mbedtls/sha1.h" | |
/* | |
* Example RSA-1024 keypair, for test purposes | |
*/ | |
#define KEY_LEN 128 | |
#define RSA_N "9292758453063D803DD603D5E777D788" \ | |
"8ED1D5BF35786190FA2F23EBC0848AEA" \ | |
"DDA92CA6C3D80B32C4D109BE0F36D6AE" \ | |
"7130B9CED7ACDF54CFC7555AC14EEBAB" \ | |
"93A89813FBF3C4F8066D2D800F7C38A8" \ | |
"1AE31942917403FF4946B0A83D3D3E05" \ | |
"EE57C6F5F5606FB5D4BC6CD34EE0801A" \ | |
"5E94BB77B07507233A0BC7BAC8F90F79" | |
#define RSA_E "10001" | |
#define RSA_D "24BF6185468786FDD303083D25E64EFC" \ | |
"66CA472BC44D253102F8B4A9D3BFA750" \ | |
"91386C0077937FE33FA3252D28855837" \ | |
"AE1B484A8A9A45F7EE8C0C634F99E8CD" \ | |
"DF79C5CE07EE72C7F123142198164234" \ | |
"CABB724CF78B8173B9F880FC86322407" \ | |
"AF1FEDFDDE2BEB674CA15F3E81A1521E" \ | |
"071513A1E85B5DFA031F21ECAE91A34D" | |
#define RSA_P "C36D0EB7FCD285223CFB5AABA5BDA3D8" \ | |
"2C01CAD19EA484A87EA4377637E75500" \ | |
"FCB2005C5C7DD6EC4AC023CDA285D796" \ | |
"C3D9E75E1EFC42488BB4F1D13AC30A57" | |
#define RSA_Q "C000DF51A7C77AE8D7C7370C1FF55B69" \ | |
"E211C2B9E5DB1ED0BF61D0D9899620F4" \ | |
"910E4168387E3C30AA1E00C339A79508" \ | |
"8452DD96A9A5EA5D9DCA68DA636032AF" | |
#define PT_LEN 24 | |
#define RSA_PT "\xAA\xBB\xCC\x03\x02\x01\x00\xFF\xFF\xFF\xFF\xFF" \ | |
"\x11\x22\x33\x0A\x0B\x0C\xCC\xDD\xDD\xDD\xDD\xDD" | |
#if defined(MBEDTLS_PKCS1_V15) | |
static int myrand( void *rng_state, unsigned char *output, size_t len ) | |
{ | |
#if !defined(__OpenBSD__) | |
size_t i; | |
if( rng_state != NULL ) | |
rng_state = NULL; | |
for( i = 0; i < len; ++i ) | |
output[i] = rand(); | |
#else | |
if( rng_state != NULL ) | |
rng_state = NULL; | |
arc4random_buf( output, len ); | |
#endif /* !OpenBSD */ | |
return( 0 ); | |
} | |
#endif /* MBEDTLS_PKCS1_V15 */ | |
/* | |
* Checkup routine | |
*/ | |
int mbedtls_rsa_self_test( int verbose ) | |
{ | |
int ret = 0; | |
#if defined(MBEDTLS_PKCS1_V15) | |
size_t len; | |
mbedtls_rsa_context rsa; | |
unsigned char rsa_plaintext[PT_LEN]; | |
unsigned char rsa_decrypted[PT_LEN]; | |
unsigned char rsa_ciphertext[KEY_LEN]; | |
#if defined(MBEDTLS_SHA1_C) | |
unsigned char sha1sum[20]; | |
#endif | |
mbedtls_mpi K; | |
mbedtls_mpi_init( &K ); | |
mbedtls_rsa_init( &rsa, MBEDTLS_RSA_PKCS_V15, 0 ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &K, 16, RSA_N ) ); | |
MBEDTLS_MPI_CHK( mbedtls_rsa_import( &rsa, &K, NULL, NULL, NULL, NULL ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &K, 16, RSA_P ) ); | |
MBEDTLS_MPI_CHK( mbedtls_rsa_import( &rsa, NULL, &K, NULL, NULL, NULL ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &K, 16, RSA_Q ) ); | |
MBEDTLS_MPI_CHK( mbedtls_rsa_import( &rsa, NULL, NULL, &K, NULL, NULL ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &K, 16, RSA_D ) ); | |
MBEDTLS_MPI_CHK( mbedtls_rsa_import( &rsa, NULL, NULL, NULL, &K, NULL ) ); | |
MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &K, 16, RSA_E ) ); | |
MBEDTLS_MPI_CHK( mbedtls_rsa_import( &rsa, NULL, NULL, NULL, NULL, &K ) ); | |
MBEDTLS_MPI_CHK( mbedtls_rsa_complete( &rsa ) ); | |
if( verbose != 0 ) | |
mbedtls_printf( " RSA key validation: " ); | |
if( mbedtls_rsa_check_pubkey( &rsa ) != 0 || | |
mbedtls_rsa_check_privkey( &rsa ) != 0 ) | |
{ | |
if( verbose != 0 ) | |
mbedtls_printf( "failed\n" ); | |
ret = 1; | |
goto cleanup; | |
} | |
if( verbose != 0 ) | |
mbedtls_printf( "passed\n PKCS#1 encryption : " ); | |
memcpy( rsa_plaintext, RSA_PT, PT_LEN ); | |
if( mbedtls_rsa_pkcs1_encrypt( &rsa, myrand, NULL, MBEDTLS_RSA_PUBLIC, | |
PT_LEN, rsa_plaintext, | |
rsa_ciphertext ) != 0 ) | |
{ | |
if( verbose != 0 ) | |
mbedtls_printf( "failed\n" ); | |
ret = 1; | |
goto cleanup; | |
} | |
if( verbose != 0 ) | |
mbedtls_printf( "passed\n PKCS#1 decryption : " ); | |
if( mbedtls_rsa_pkcs1_decrypt( &rsa, myrand, NULL, MBEDTLS_RSA_PRIVATE, | |
&len, rsa_ciphertext, rsa_decrypted, | |
sizeof(rsa_decrypted) ) != 0 ) | |
{ | |
if( verbose != 0 ) | |
mbedtls_printf( "failed\n" ); | |
ret = 1; | |
goto cleanup; | |
} | |
if( memcmp( rsa_decrypted, rsa_plaintext, len ) != 0 ) | |
{ | |
if( verbose != 0 ) | |
mbedtls_printf( "failed\n" ); | |
ret = 1; | |
goto cleanup; | |
} | |
if( verbose != 0 ) | |
mbedtls_printf( "passed\n" ); | |
#if defined(MBEDTLS_SHA1_C) | |
if( verbose != 0 ) | |
mbedtls_printf( " PKCS#1 data sign : " ); | |
if( mbedtls_sha1_ret( rsa_plaintext, PT_LEN, sha1sum ) != 0 ) | |
{ | |
if( verbose != 0 ) | |
mbedtls_printf( "failed\n" ); | |
return( 1 ); | |
} | |
if( mbedtls_rsa_pkcs1_sign( &rsa, myrand, NULL, | |
MBEDTLS_RSA_PRIVATE, MBEDTLS_MD_SHA1, 0, | |
sha1sum, rsa_ciphertext ) != 0 ) | |
{ | |
if( verbose != 0 ) | |
mbedtls_printf( "failed\n" ); | |
ret = 1; | |
goto cleanup; | |
} | |
if( verbose != 0 ) | |
mbedtls_printf( "passed\n PKCS#1 sig. verify: " ); | |
if( mbedtls_rsa_pkcs1_verify( &rsa, NULL, NULL, | |
MBEDTLS_RSA_PUBLIC, MBEDTLS_MD_SHA1, 0, | |
sha1sum, rsa_ciphertext ) != 0 ) | |
{ | |
if( verbose != 0 ) | |
mbedtls_printf( "failed\n" ); | |
ret = 1; | |
goto cleanup; | |
} | |
if( verbose != 0 ) | |
mbedtls_printf( "passed\n" ); | |
#endif /* MBEDTLS_SHA1_C */ | |
if( verbose != 0 ) | |
mbedtls_printf( "\n" ); | |
cleanup: | |
mbedtls_mpi_free( &K ); | |
mbedtls_rsa_free( &rsa ); | |
#else /* MBEDTLS_PKCS1_V15 */ | |
((void) verbose); | |
#endif /* MBEDTLS_PKCS1_V15 */ | |
return( ret ); | |
} | |
#endif /* MBEDTLS_SELF_TEST */ | |
#endif /* MBEDTLS_RSA_C */ |