| /* |
| * The RSA public-key cryptosystem |
| * |
| * Copyright The Mbed TLS Contributors |
| * 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. |
| */ |
| |
| /* |
| * 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 |
| * |
| */ |
| |
| #include "common.h" |
| |
| #if defined(MBEDTLS_RSA_C) |
| |
| #include "mbedtls/rsa.h" |
| #include "rsa_alt_helpers.h" |
| #include "mbedtls/oid.h" |
| #include "mbedtls/platform_util.h" |
| #include "mbedtls/error.h" |
| |
| #include <string.h> |
| |
| #if defined(MBEDTLS_PKCS1_V21) |
| #include "mbedtls/md.h" |
| #endif |
| |
| #if defined(MBEDTLS_PKCS1_V15) && !defined(__OpenBSD__) && !defined(__NetBSD__) |
| #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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| 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_ERROR_ADD( 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_ERROR_ADD( 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; |
| #if !defined(MBEDTLS_RSA_NO_CRT) |
| int have_DP, have_DQ, have_QP; |
| #endif |
| 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 ); |
| |
| #if !defined(MBEDTLS_RSA_NO_CRT) |
| have_DP = ( mbedtls_mpi_cmp_int( &ctx->DP, 0 ) != 0 ); |
| have_DQ = ( mbedtls_mpi_cmp_int( &ctx->DQ, 0 ) != 0 ); |
| have_QP = ( mbedtls_mpi_cmp_int( &ctx->QP, 0 ) != 0 ); |
| #endif |
| |
| /* |
| * 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_ERROR_ADD( 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_ERROR_ADD( 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_ERROR_ADD( 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 && ! ( have_DP && have_DQ && have_QP ) ) |
| { |
| ret = mbedtls_rsa_deduce_crt( &ctx->P, &ctx->Q, &ctx->D, |
| &ctx->DP, &ctx->DQ, &ctx->QP ); |
| if( ret != 0 ) |
| return( MBEDTLS_ERROR_ADD( 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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| 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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| 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_ERROR_ADD( 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_ERROR_ADD( MBEDTLS_ERR_RSA_BAD_INPUT_DATA, ret ) ); |
| } |
| #endif |
| |
| return( 0 ); |
| } |
| |
| /* |
| * Initialize an RSA context |
| */ |
| void mbedtls_rsa_init( mbedtls_rsa_context *ctx ) |
| { |
| RSA_VALIDATE( ctx != NULL ); |
| |
| memset( ctx, 0, sizeof( mbedtls_rsa_context ) ); |
| |
| ctx->padding = MBEDTLS_RSA_PKCS_V15; |
| ctx->hash_id = MBEDTLS_MD_NONE; |
| |
| #if defined(MBEDTLS_THREADING_C) |
| /* Set ctx->ver to nonzero to indicate that the mutex has been |
| * initialized and will need to be freed. */ |
| ctx->ver = 1; |
| mbedtls_mutex_init( &ctx->mutex ); |
| #endif |
| } |
| |
| /* |
| * Set padding for an existing RSA context |
| */ |
| int mbedtls_rsa_set_padding( mbedtls_rsa_context *ctx, int padding, |
| mbedtls_md_type_t hash_id ) |
| { |
| switch( padding ) |
| { |
| #if defined(MBEDTLS_PKCS1_V15) |
| case MBEDTLS_RSA_PKCS_V15: |
| break; |
| #endif |
| |
| #if defined(MBEDTLS_PKCS1_V21) |
| case MBEDTLS_RSA_PKCS_V21: |
| break; |
| #endif |
| default: |
| return( MBEDTLS_ERR_RSA_INVALID_PADDING ); |
| } |
| |
| if( ( padding == MBEDTLS_RSA_PKCS_V21 ) && |
| ( hash_id != MBEDTLS_MD_NONE ) ) |
| { |
| const mbedtls_md_info_t *md_info; |
| |
| md_info = mbedtls_md_info_from_type( hash_id ); |
| if( md_info == NULL ) |
| return( MBEDTLS_ERR_RSA_INVALID_PADDING ); |
| } |
| |
| ctx->padding = padding; |
| ctx->hash_id = hash_id; |
| |
| return( 0 ); |
| } |
| |
| /* |
| * 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_ERR_ERROR_CORRUPTION_DETECTED; |
| mbedtls_mpi H, G, L; |
| int prime_quality = 0; |
| RSA_VALIDATE_RET( ctx != NULL ); |
| RSA_VALIDATE_RET( f_rng != NULL ); |
| |
| /* |
| * 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 ); |
| |
| if( nbits < 128 || exponent < 3 || nbits % 2 != 0 ) |
| { |
| ret = MBEDTLS_ERR_RSA_BAD_INPUT_DATA; |
| goto cleanup; |
| } |
| |
| /* |
| * 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 ); |
| |
| if( ( -ret & ~0x7f ) == 0 ) |
| ret = MBEDTLS_ERROR_ADD( MBEDTLS_ERR_RSA_KEY_GEN_FAILED, ret ); |
| return( 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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| 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_ERROR_ADD( 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; |
| mbedtls_mpi R; |
| |
| mbedtls_mpi_init( &R ); |
| |
| 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 ) |
| { |
| ret = MBEDTLS_ERR_RSA_RNG_FAILED; |
| goto cleanup; |
| } |
| |
| MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->Vf, ctx->len - 1, f_rng, p_rng ) ); |
| |
| /* Compute Vf^-1 as R * (R Vf)^-1 to avoid leaks from inv_mod. */ |
| MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &R, ctx->len - 1, f_rng, p_rng ) ); |
| MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vi, &ctx->Vf, &R ) ); |
| MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vi, &ctx->Vi, &ctx->N ) ); |
| |
| /* At this point, Vi is invertible mod N if and only if both Vf and R |
| * are invertible mod N. If one of them isn't, we don't need to know |
| * which one, we just loop and choose new values for both of them. |
| * (Each iteration succeeds with overwhelming probability.) */ |
| ret = mbedtls_mpi_inv_mod( &ctx->Vi, &ctx->Vi, &ctx->N ); |
| if( ret != 0 && ret != MBEDTLS_ERR_MPI_NOT_ACCEPTABLE ) |
| goto cleanup; |
| |
| } while( ret == MBEDTLS_ERR_MPI_NOT_ACCEPTABLE ); |
| |
| /* Finish the computation of Vf^-1 = R * (R Vf)^-1 */ |
| MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vi, &ctx->Vi, &R ) ); |
| MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vi, &ctx->Vi, &ctx->N ) ); |
| |
| /* Blinding value: Vi = Vf^(-e) mod N |
| * (Vi already contains Vf^-1 at this point) */ |
| MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->Vi, &ctx->Vi, &ctx->E, &ctx->N, &ctx->RN ) ); |
| |
| |
| cleanup: |
| mbedtls_mpi_free( &R ); |
| |
| 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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| 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 && ret >= -0x007f ) |
| return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_RSA_PRIVATE_FAILED, ret ) ); |
| |
| return( ret ); |
| } |
| |
| #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, |
| const unsigned char *label, size_t label_len, |
| size_t ilen, |
| const unsigned char *input, |
| unsigned char *output ) |
| { |
| size_t olen; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| 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( output != NULL ); |
| RSA_VALIDATE_RET( ilen == 0 || input != NULL ); |
| RSA_VALIDATE_RET( label_len == 0 || label != NULL ); |
| |
| 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_ERROR_ADD( 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( mbedtls_rsa_public( ctx, 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, size_t ilen, |
| const unsigned char *input, |
| unsigned char *output ) |
| { |
| size_t nb_pad, olen; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *p = output; |
| |
| RSA_VALIDATE_RET( ctx != NULL ); |
| RSA_VALIDATE_RET( output != NULL ); |
| RSA_VALIDATE_RET( ilen == 0 || input != NULL ); |
| |
| 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( 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_ERROR_ADD( MBEDTLS_ERR_RSA_RNG_FAILED, ret ) ); |
| |
| p++; |
| } |
| |
| *p++ = 0; |
| if( ilen != 0 ) |
| memcpy( p, input, ilen ); |
| |
| return( mbedtls_rsa_public( ctx, 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, |
| size_t ilen, |
| const unsigned char *input, |
| unsigned char *output ) |
| { |
| RSA_VALIDATE_RET( ctx != NULL ); |
| 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, |
| 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, 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, |
| 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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| 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( 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( 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 = 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, |
| size_t *olen, |
| const unsigned char *input, |
| unsigned char *output, |
| size_t output_max_len ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| 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( 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( 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 = 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]; |
| |
| |
| /* 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; |
| } |
| |
| |
| /* 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, |
| size_t *olen, |
| const unsigned char *input, |
| unsigned char *output, |
| size_t output_max_len) |
| { |
| RSA_VALIDATE_RET( ctx != NULL ); |
| 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, 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, NULL, 0, |
| olen, input, output, |
| output_max_len ); |
| #endif |
| |
| default: |
| return( MBEDTLS_ERR_RSA_INVALID_PADDING ); |
| } |
| } |
| |
| #if defined(MBEDTLS_PKCS1_V21) |
| static int rsa_rsassa_pss_sign( mbedtls_rsa_context *ctx, |
| int (*f_rng)(void *, unsigned char *, size_t), |
| void *p_rng, |
| mbedtls_md_type_t md_alg, |
| unsigned int hashlen, |
| const unsigned char *hash, |
| int saltlen, |
| unsigned char *sig ) |
| { |
| size_t olen; |
| unsigned char *p = sig; |
| unsigned char *salt = NULL; |
| size_t slen, min_slen, hlen, offset = 0; |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| size_t msb; |
| const mbedtls_md_info_t *md_info; |
| mbedtls_md_context_t md_ctx; |
| RSA_VALIDATE_RET( ctx != NULL ); |
| RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE && |
| hashlen == 0 ) || |
| hash != NULL ); |
| RSA_VALIDATE_RET( sig != NULL ); |
| |
| if( 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 ); |
| |
| if (saltlen == MBEDTLS_RSA_SALT_LEN_ANY) |
| { |
| /* Calculate the largest possible salt length, up to the hash size. |
| * Normally this is the hash length, which is the maximum salt length |
| * according to FIPS 185-4 §5.5 (e) and common practice. 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; |
| } |
| else if ( (saltlen < 0) || (saltlen + hlen + 2 > olen) ) |
| { |
| return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); |
| } |
| else |
| { |
| slen = (size_t) saltlen; |
| } |
| |
| memset( sig, 0, olen ); |
| |
| /* 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; |
| |
| /* Generate salt of length slen in place in the encoded message */ |
| salt = p; |
| if( ( ret = f_rng( p_rng, salt, slen ) ) != 0 ) |
| return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_RSA_RNG_FAILED, ret ) ); |
| |
| 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; |
| |
| exit: |
| mbedtls_md_free( &md_ctx ); |
| |
| if( ret != 0 ) |
| return( ret ); |
| |
| return mbedtls_rsa_private( ctx, f_rng, p_rng, sig, sig ); |
| } |
| |
| /* |
| * Implementation of the PKCS#1 v2.1 RSASSA-PSS-SIGN function with |
| * the option to pass in the salt length. |
| */ |
| int mbedtls_rsa_rsassa_pss_sign_ext( mbedtls_rsa_context *ctx, |
| int (*f_rng)(void *, unsigned char *, size_t), |
| void *p_rng, |
| mbedtls_md_type_t md_alg, |
| unsigned int hashlen, |
| const unsigned char *hash, |
| int saltlen, |
| unsigned char *sig ) |
| { |
| return rsa_rsassa_pss_sign( ctx, f_rng, p_rng, md_alg, |
| hashlen, hash, saltlen, sig ); |
| } |
| |
| |
| /* |
| * 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, |
| mbedtls_md_type_t md_alg, |
| unsigned int hashlen, |
| const unsigned char *hash, |
| unsigned char *sig ) |
| { |
| return rsa_rsassa_pss_sign( ctx, f_rng, p_rng, md_alg, |
| hashlen, hash, 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-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, |
| mbedtls_md_type_t md_alg, |
| unsigned int hashlen, |
| const unsigned char *hash, |
| unsigned char *sig ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| unsigned char *sig_try = NULL, *verif = NULL; |
| |
| RSA_VALIDATE_RET( ctx != NULL ); |
| RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE && |
| hashlen == 0 ) || |
| hash != NULL ); |
| RSA_VALIDATE_RET( sig != NULL ); |
| |
| if( 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 ); |
| |
| /* 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, |
| mbedtls_md_type_t md_alg, |
| unsigned int hashlen, |
| const unsigned char *hash, |
| unsigned char *sig ) |
| { |
| RSA_VALIDATE_RET( ctx != NULL ); |
| 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, |
| 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, 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, |
| 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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| 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( sig != NULL ); |
| RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE && |
| hashlen == 0 ) || |
| hash != NULL ); |
| |
| siglen = ctx->len; |
| |
| if( siglen < 16 || siglen > sizeof( buf ) ) |
| return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA ); |
| |
| ret = mbedtls_rsa_public( ctx, 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, |
| 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( 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, |
| 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, |
| 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( sig != NULL ); |
| RSA_VALIDATE_RET( ( md_alg == MBEDTLS_MD_NONE && |
| hashlen == 0 ) || |
| hash != NULL ); |
| |
| sig_len = ctx->len; |
| |
| /* |
| * 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 = mbedtls_rsa_public( ctx, 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, |
| 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( 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, md_alg, |
| hashlen, hash, sig ); |
| #endif |
| |
| #if defined(MBEDTLS_PKCS1_V21) |
| case MBEDTLS_RSA_PKCS_V21: |
| return mbedtls_rsa_rsassa_pss_verify( ctx, 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 = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| RSA_VALIDATE_RET( dst != NULL ); |
| RSA_VALIDATE_RET( src != NULL ); |
| |
| 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) |
| /* Free the mutex, but only if it hasn't been freed already. */ |
| if( ctx->ver != 0 ) |
| { |
| mbedtls_mutex_free( &ctx->mutex ); |
| ctx->ver = 0; |
| } |
| #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__) && !defined(__NetBSD__) |
| 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 && !NetBSD */ |
| |
| 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_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, |
| 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, |
| &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_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, 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 */ |