Mark Radbourne
mbed TLS Build
Dependents: Encrypt_Decrypt1 mbed_blink_tls encrypt encrypt
Diff: library/rsa.c
- Revision:
- 0:cdf462088d13
diff -r 000000000000 -r cdf462088d13 library/rsa.c
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/library/rsa.c Thu Jan 05 00:18:44 2017 +0000
@@ -0,0 +1,1730 @@
+/*
+ * 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
+ *
+ */
+
+#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/oid.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
+
+/*
+ * Initialize an RSA context
+ */
+void mbedtls_rsa_init( mbedtls_rsa_context *ctx,
+ int padding,
+ int hash_id )
+{
+ 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 )
+{
+ ctx->padding = padding;
+ ctx->hash_id = hash_id;
+}
+
+#if defined(MBEDTLS_GENPRIME)
+
+/*
+ * Generate an RSA keypair
+ */
+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 P1, Q1, H, G;
+
+ if( f_rng == NULL || nbits < 128 || exponent < 3 )
+ return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
+
+ if( nbits % 2 )
+ return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
+
+ mbedtls_mpi_init( &P1 ); mbedtls_mpi_init( &Q1 );
+ mbedtls_mpi_init( &H ); mbedtls_mpi_init( &G );
+
+ /*
+ * find primes P and Q with Q < P so that:
+ * GCD( E, (P-1)*(Q-1) ) == 1
+ */
+ MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &ctx->E, exponent ) );
+
+ do
+ {
+ MBEDTLS_MPI_CHK( mbedtls_mpi_gen_prime( &ctx->P, nbits >> 1, 0,
+ f_rng, p_rng ) );
+
+ MBEDTLS_MPI_CHK( mbedtls_mpi_gen_prime( &ctx->Q, nbits >> 1, 0,
+ f_rng, p_rng ) );
+
+ if( mbedtls_mpi_cmp_mpi( &ctx->P, &ctx->Q ) == 0 )
+ continue;
+
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->N, &ctx->P, &ctx->Q ) );
+ if( mbedtls_mpi_bitlen( &ctx->N ) != nbits )
+ continue;
+
+ if( mbedtls_mpi_cmp_mpi( &ctx->P, &ctx->Q ) < 0 )
+ mbedtls_mpi_swap( &ctx->P, &ctx->Q );
+
+ MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &P1, &ctx->P, 1 ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &Q1, &ctx->Q, 1 ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &H, &P1, &Q1 ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( &G, &ctx->E, &H ) );
+ }
+ while( mbedtls_mpi_cmp_int( &G, 1 ) != 0 );
+
+ /*
+ * D = E^-1 mod ((P-1)*(Q-1))
+ * DP = D mod (P - 1)
+ * DQ = D mod (Q - 1)
+ * QP = Q^-1 mod P
+ */
+ MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &ctx->D , &ctx->E, &H ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->DP, &ctx->D, &P1 ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->DQ, &ctx->D, &Q1 ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &ctx->QP, &ctx->Q, &ctx->P ) );
+
+ ctx->len = ( mbedtls_mpi_bitlen( &ctx->N ) + 7 ) >> 3;
+
+cleanup:
+
+ mbedtls_mpi_free( &P1 ); mbedtls_mpi_free( &Q1 ); mbedtls_mpi_free( &H ); mbedtls_mpi_free( &G );
+
+ 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 )
+{
+ if( !ctx->N.p || !ctx->E.p )
+ return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
+
+ if( ( ctx->N.p[0] & 1 ) == 0 ||
+ ( ctx->E.p[0] & 1 ) == 0 )
+ return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
+
+ if( mbedtls_mpi_bitlen( &ctx->N ) < 128 ||
+ mbedtls_mpi_bitlen( &ctx->N ) > MBEDTLS_MPI_MAX_BITS )
+ return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
+
+ if( 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 a private RSA key
+ */
+int mbedtls_rsa_check_privkey( const mbedtls_rsa_context *ctx )
+{
+ int ret;
+ mbedtls_mpi PQ, DE, P1, Q1, H, I, G, G2, L1, L2, DP, DQ, QP;
+
+ if( ( ret = mbedtls_rsa_check_pubkey( ctx ) ) != 0 )
+ return( ret );
+
+ if( !ctx->P.p || !ctx->Q.p || !ctx->D.p )
+ return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED );
+
+ mbedtls_mpi_init( &PQ ); mbedtls_mpi_init( &DE ); mbedtls_mpi_init( &P1 ); mbedtls_mpi_init( &Q1 );
+ mbedtls_mpi_init( &H ); mbedtls_mpi_init( &I ); mbedtls_mpi_init( &G ); mbedtls_mpi_init( &G2 );
+ mbedtls_mpi_init( &L1 ); mbedtls_mpi_init( &L2 ); mbedtls_mpi_init( &DP ); mbedtls_mpi_init( &DQ );
+ mbedtls_mpi_init( &QP );
+
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &PQ, &ctx->P, &ctx->Q ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &DE, &ctx->D, &ctx->E ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &P1, &ctx->P, 1 ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &Q1, &ctx->Q, 1 ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &H, &P1, &Q1 ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( &G, &ctx->E, &H ) );
+
+ MBEDTLS_MPI_CHK( mbedtls_mpi_gcd( &G2, &P1, &Q1 ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_div_mpi( &L1, &L2, &H, &G2 ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &I, &DE, &L1 ) );
+
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &DP, &ctx->D, &P1 ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &DQ, &ctx->D, &Q1 ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &QP, &ctx->Q, &ctx->P ) );
+ /*
+ * Check for a valid PKCS1v2 private key
+ */
+ if( mbedtls_mpi_cmp_mpi( &PQ, &ctx->N ) != 0 ||
+ mbedtls_mpi_cmp_mpi( &DP, &ctx->DP ) != 0 ||
+ mbedtls_mpi_cmp_mpi( &DQ, &ctx->DQ ) != 0 ||
+ mbedtls_mpi_cmp_mpi( &QP, &ctx->QP ) != 0 ||
+ mbedtls_mpi_cmp_int( &L2, 0 ) != 0 ||
+ mbedtls_mpi_cmp_int( &I, 1 ) != 0 ||
+ mbedtls_mpi_cmp_int( &G, 1 ) != 0 )
+ {
+ ret = MBEDTLS_ERR_RSA_KEY_CHECK_FAILED;
+ }
+
+cleanup:
+ mbedtls_mpi_free( &PQ ); mbedtls_mpi_free( &DE ); mbedtls_mpi_free( &P1 ); mbedtls_mpi_free( &Q1 );
+ mbedtls_mpi_free( &H ); mbedtls_mpi_free( &I ); mbedtls_mpi_free( &G ); mbedtls_mpi_free( &G2 );
+ mbedtls_mpi_free( &L1 ); mbedtls_mpi_free( &L2 ); mbedtls_mpi_free( &DP ); mbedtls_mpi_free( &DQ );
+ mbedtls_mpi_free( &QP );
+
+ if( ret == MBEDTLS_ERR_RSA_KEY_CHECK_FAILED )
+ return( ret );
+
+ if( ret != 0 )
+ return( MBEDTLS_ERR_RSA_KEY_CHECK_FAILED + ret );
+
+ 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 )
+{
+ 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;
+
+ 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 );
+}
+
+/*
+ * 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;
+ mbedtls_mpi T, T1, T2;
+
+ /* Make sure we have private key info, prevent possible misuse */
+ if( ctx->P.p == NULL || ctx->Q.p == NULL || ctx->D.p == NULL )
+ return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
+
+ mbedtls_mpi_init( &T ); mbedtls_mpi_init( &T1 ); mbedtls_mpi_init( &T2 );
+
+#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;
+ }
+
+ 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 ) );
+ }
+
+#if defined(MBEDTLS_RSA_NO_CRT)
+ MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &T, &T, &ctx->D, &ctx->N, &ctx->RN ) );
+#else
+ /*
+ * faster decryption using the CRT
+ *
+ * T1 = input ^ dP mod P
+ * T2 = input ^ dQ mod Q
+ */
+ MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &T1, &T, &ctx->DP, &ctx->P, &ctx->RP ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &T2, &T, &ctx->DQ, &ctx->Q, &ctx->RQ ) );
+
+ /*
+ * T = (T1 - T2) * (Q^-1 mod P) mod P
+ */
+ MBEDTLS_MPI_CHK( mbedtls_mpi_sub_mpi( &T, &T1, &T2 ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T1, &T, &ctx->QP ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &T, &T1, &ctx->P ) );
+
+ /*
+ * T = T2 + T * Q
+ */
+ MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &T1, &T, &ctx->Q ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( &T, &T2, &T1 ) );
+#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 ) );
+ }
+
+ 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( &T ); mbedtls_mpi_free( &T1 ); mbedtls_mpi_free( &T2 );
+
+ 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 void 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;
+
+ 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;
+
+ mbedtls_md_starts( md_ctx );
+ mbedtls_md_update( md_ctx, src, slen );
+ mbedtls_md_update( md_ctx, counter, 4 );
+ mbedtls_md_finish( md_ctx, mask );
+
+ for( i = 0; i < use_len; ++i )
+ *p++ ^= mask[i];
+
+ counter[3]++;
+
+ dlen -= use_len;
+ }
+}
+#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;
+
+ 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 */
+ mbedtls_md( md_info, label, label_len, p );
+ p += hlen;
+ p += olen - 2 * hlen - 2 - ilen;
+ *p++ = 1;
+ memcpy( p, input, ilen );
+
+ mbedtls_md_init( &md_ctx );
+ if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 )
+ {
+ mbedtls_md_free( &md_ctx );
+ return( ret );
+ }
+
+ /* maskedDB: Apply dbMask to DB */
+ mgf_mask( output + hlen + 1, olen - hlen - 1, output + 1, hlen,
+ &md_ctx );
+
+ /* maskedSeed: Apply seedMask to seed */
+ mgf_mask( output + 1, hlen, output + hlen + 1, olen - hlen - 1,
+ &md_ctx );
+
+ mbedtls_md_free( &md_ctx );
+
+ 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;
+
+ if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V15 )
+ return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
+
+ // We don't check p_rng because it won't be dereferenced here
+ if( f_rng == NULL || input == NULL || output == NULL )
+ 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 )
+ {
+ *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;
+ 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 )
+{
+ 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;
+
+ /*
+ * 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 )
+ return( ret );
+
+ /*
+ * 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 );
+ return( ret );
+ }
+
+
+ /* Generate lHash */
+ mbedtls_md( md_info, label, label_len, lhash );
+
+ /* seed: Apply seedMask to maskedSeed */
+ mgf_mask( buf + 1, hlen, buf + hlen + 1, ilen - hlen - 1,
+ &md_ctx );
+
+ /* DB: Apply dbMask to maskedDB */
+ mgf_mask( buf + hlen + 1, ilen - hlen - 1, buf + 1, hlen,
+ &md_ctx );
+
+ mbedtls_md_free( &md_ctx );
+
+ /*
+ * 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 )
+ return( MBEDTLS_ERR_RSA_INVALID_PADDING );
+
+ if( ilen - ( p - buf ) > output_max_len )
+ return( MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE );
+
+ *olen = ilen - (p - buf);
+ memcpy( output, p, *olen );
+
+ return( 0 );
+}
+#endif /* MBEDTLS_PKCS1_V21 */
+
+#if defined(MBEDTLS_PKCS1_V15)
+/*
+ * 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, pad_count = 0, i;
+ unsigned char *p, bad, pad_done = 0;
+ unsigned char buf[MBEDTLS_MPI_MAX_SIZE];
+
+ if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V15 )
+ return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
+
+ ilen = ctx->len;
+
+ 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 )
+ return( ret );
+
+ p = buf;
+ bad = 0;
+
+ /*
+ * Check and get padding len in "constant-time"
+ */
+ bad |= *p++; /* First byte must be 0 */
+
+ /* This test does not depend on secret data */
+ if( mode == MBEDTLS_RSA_PRIVATE )
+ {
+ bad |= *p++ ^ MBEDTLS_RSA_CRYPT;
+
+ /* Get padding len, but always read till end of buffer
+ * (minus one, for the 00 byte) */
+ for( i = 0; i < ilen - 3; i++ )
+ {
+ pad_done |= ((p[i] | (unsigned char)-p[i]) >> 7) ^ 1;
+ pad_count += ((pad_done | (unsigned char)-pad_done) >> 7) ^ 1;
+ }
+
+ p += pad_count;
+ bad |= *p++; /* Must be zero */
+ }
+ else
+ {
+ bad |= *p++ ^ MBEDTLS_RSA_SIGN;
+
+ /* Get padding len, but always read till end of buffer
+ * (minus one, for the 00 byte) */
+ for( i = 0; i < ilen - 3; i++ )
+ {
+ pad_done |= ( p[i] != 0xFF );
+ pad_count += ( pad_done == 0 );
+ }
+
+ p += pad_count;
+ bad |= *p++; /* Must be zero */
+ }
+
+ bad |= ( pad_count < 8 );
+
+ if( bad )
+ return( MBEDTLS_ERR_RSA_INVALID_PADDING );
+
+ if( ilen - ( p - buf ) > output_max_len )
+ return( MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE );
+
+ *olen = ilen - (p - buf);
+ memcpy( output, p, *olen );
+
+ return( 0 );
+}
+#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)
+{
+ 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];
+ unsigned int slen, hlen, offset = 0;
+ int ret;
+ size_t msb;
+ const mbedtls_md_info_t *md_info;
+ mbedtls_md_context_t md_ctx;
+
+ 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 );
+ slen = hlen;
+
+ if( olen < hlen + slen + 2 )
+ return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
+
+ 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 * 2 - 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 )
+ {
+ mbedtls_md_free( &md_ctx );
+ return( ret );
+ }
+
+ /* Generate H = Hash( M' ) */
+ mbedtls_md_starts( &md_ctx );
+ mbedtls_md_update( &md_ctx, p, 8 );
+ mbedtls_md_update( &md_ctx, hash, hashlen );
+ mbedtls_md_update( &md_ctx, salt, slen );
+ mbedtls_md_finish( &md_ctx, p );
+
+ /* Compensate for boundary condition when applying mask */
+ if( msb % 8 == 0 )
+ offset = 1;
+
+ /* maskedDB: Apply dbMask to DB */
+ mgf_mask( sig + offset, olen - hlen - 1 - offset, p, hlen, &md_ctx );
+
+ mbedtls_md_free( &md_ctx );
+
+ msb = mbedtls_mpi_bitlen( &ctx->N ) - 1;
+ sig[0] &= 0xFF >> ( olen * 8 - msb );
+
+ p += hlen;
+ *p++ = 0xBC;
+
+ 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
+ */
+/*
+ * 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 )
+{
+ size_t nb_pad, olen, oid_size = 0;
+ unsigned char *p = sig;
+ const char *oid = NULL;
+ unsigned char *sig_try = NULL, *verif = NULL;
+ size_t i;
+ unsigned char diff;
+ volatile unsigned char diff_no_optimize;
+ int ret;
+
+ if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V15 )
+ return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
+
+ olen = ctx->len;
+ nb_pad = olen - 3;
+
+ 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 );
+
+ nb_pad -= 10 + oid_size;
+
+ hashlen = mbedtls_md_get_size( md_info );
+ }
+
+ nb_pad -= hashlen;
+
+ if( ( nb_pad < 8 ) || ( nb_pad > olen ) )
+ return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
+
+ *p++ = 0;
+ *p++ = MBEDTLS_RSA_SIGN;
+ memset( p, 0xFF, nb_pad );
+ p += nb_pad;
+ *p++ = 0;
+
+ if( md_alg == MBEDTLS_MD_NONE )
+ {
+ memcpy( p, hash, hashlen );
+ }
+ else
+ {
+ /*
+ * DigestInfo ::= SEQUENCE {
+ * digestAlgorithm DigestAlgorithmIdentifier,
+ * digest Digest }
+ *
+ * DigestAlgorithmIdentifier ::= AlgorithmIdentifier
+ *
+ * Digest ::= OCTET STRING
+ */
+ *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++ = oid_size & 0xFF;
+ memcpy( p, oid, oid_size );
+ p += oid_size;
+ *p++ = MBEDTLS_ASN1_NULL;
+ *p++ = 0x00;
+ *p++ = MBEDTLS_ASN1_OCTET_STRING;
+ *p++ = hashlen;
+ memcpy( p, hash, hashlen );
+ }
+
+ if( mode == MBEDTLS_RSA_PUBLIC )
+ return( mbedtls_rsa_public( ctx, sig, sig ) );
+
+ /*
+ * 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 ) );
+
+ /* Compare in constant time just in case */
+ for( diff = 0, i = 0; i < ctx->len; i++ )
+ diff |= verif[i] ^ sig[i];
+ diff_no_optimize = diff;
+
+ if( diff_no_optimize != 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 )
+{
+ 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 result[MBEDTLS_MD_MAX_SIZE];
+ unsigned char zeros[8];
+ unsigned int hlen;
+ size_t slen, msb;
+ const mbedtls_md_info_t *md_info;
+ mbedtls_md_context_t md_ctx;
+ unsigned char buf[MBEDTLS_MPI_MAX_SIZE];
+
+ 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 );
+ slen = siglen - hlen - 1; /* Currently length of salt + padding */
+
+ memset( zeros, 0, 8 );
+
+ /*
+ * Note: EMSA-PSS verification is over the length of N - 1 bits
+ */
+ msb = mbedtls_mpi_bitlen( &ctx->N ) - 1;
+
+ /* Compensate for boundary condition when applying mask */
+ if( msb % 8 == 0 )
+ {
+ p++;
+ siglen -= 1;
+ }
+ if( buf[0] >> ( 8 - siglen * 8 + msb ) )
+ return( MBEDTLS_ERR_RSA_BAD_INPUT_DATA );
+
+ mbedtls_md_init( &md_ctx );
+ if( ( ret = mbedtls_md_setup( &md_ctx, md_info, 0 ) ) != 0 )
+ {
+ mbedtls_md_free( &md_ctx );
+ return( ret );
+ }
+
+ mgf_mask( p, siglen - hlen - 1, p + siglen - hlen - 1, hlen, &md_ctx );
+
+ buf[0] &= 0xFF >> ( siglen * 8 - msb );
+
+ while( p < buf + siglen && *p == 0 )
+ p++;
+
+ if( p == buf + siglen ||
+ *p++ != 0x01 )
+ {
+ mbedtls_md_free( &md_ctx );
+ return( MBEDTLS_ERR_RSA_INVALID_PADDING );
+ }
+
+ /* Actual salt len */
+ slen -= p - buf;
+
+ if( expected_salt_len != MBEDTLS_RSA_SALT_LEN_ANY &&
+ slen != (size_t) expected_salt_len )
+ {
+ mbedtls_md_free( &md_ctx );
+ return( MBEDTLS_ERR_RSA_INVALID_PADDING );
+ }
+
+ /*
+ * Generate H = Hash( M' )
+ */
+ mbedtls_md_starts( &md_ctx );
+ mbedtls_md_update( &md_ctx, zeros, 8 );
+ mbedtls_md_update( &md_ctx, hash, hashlen );
+ mbedtls_md_update( &md_ctx, p, slen );
+ mbedtls_md_finish( &md_ctx, result );
+
+ mbedtls_md_free( &md_ctx );
+
+ if( memcmp( p + slen, result, hlen ) == 0 )
+ return( 0 );
+ else
+ return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
+}
+
+/*
+ * 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 = ( 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;
+ size_t len, siglen, asn1_len;
+ unsigned char *p, *end;
+ mbedtls_md_type_t msg_md_alg;
+ const mbedtls_md_info_t *md_info;
+ mbedtls_asn1_buf oid;
+ unsigned char buf[MBEDTLS_MPI_MAX_SIZE];
+
+ if( mode == MBEDTLS_RSA_PRIVATE && ctx->padding != MBEDTLS_RSA_PKCS_V15 )
+ 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( *p++ != 0 || *p++ != MBEDTLS_RSA_SIGN )
+ return( MBEDTLS_ERR_RSA_INVALID_PADDING );
+
+ while( *p != 0 )
+ {
+ if( p >= buf + siglen - 1 || *p != 0xFF )
+ return( MBEDTLS_ERR_RSA_INVALID_PADDING );
+ p++;
+ }
+ p++;
+
+ len = siglen - ( p - buf );
+
+ if( len == hashlen && md_alg == MBEDTLS_MD_NONE )
+ {
+ if( memcmp( p, hash, hashlen ) == 0 )
+ return( 0 );
+ else
+ return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
+ }
+
+ 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 );
+
+ end = p + len;
+
+ /*
+ * Parse the ASN.1 structure inside the PKCS#1 v1.5 structure
+ */
+ if( ( ret = mbedtls_asn1_get_tag( &p, end, &asn1_len,
+ MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
+ return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
+
+ if( asn1_len + 2 != len )
+ return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
+
+ if( ( ret = mbedtls_asn1_get_tag( &p, end, &asn1_len,
+ MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 )
+ return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
+
+ if( asn1_len + 6 + hashlen != len )
+ return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
+
+ if( ( ret = mbedtls_asn1_get_tag( &p, end, &oid.len, MBEDTLS_ASN1_OID ) ) != 0 )
+ return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
+
+ oid.p = p;
+ p += oid.len;
+
+ if( mbedtls_oid_get_md_alg( &oid, &msg_md_alg ) != 0 )
+ return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
+
+ if( md_alg != msg_md_alg )
+ return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
+
+ /*
+ * assume the algorithm parameters must be NULL
+ */
+ if( ( ret = mbedtls_asn1_get_tag( &p, end, &asn1_len, MBEDTLS_ASN1_NULL ) ) != 0 )
+ return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
+
+ if( ( ret = mbedtls_asn1_get_tag( &p, end, &asn1_len, MBEDTLS_ASN1_OCTET_STRING ) ) != 0 )
+ return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
+
+ if( asn1_len != hashlen )
+ return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
+
+ if( memcmp( p, hash, hashlen ) != 0 )
+ return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
+
+ p += hashlen;
+
+ if( p != end )
+ return( MBEDTLS_ERR_RSA_VERIFY_FAILED );
+
+ return( 0 );
+}
+#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 )
+{
+ 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;
+
+ 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 ) );
+ 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->RN, &src->RN ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->RP, &src->RP ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &dst->RQ, &src->RQ ) );
+
+ 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 )
+{
+ mbedtls_mpi_free( &ctx->Vi ); mbedtls_mpi_free( &ctx->Vf );
+ mbedtls_mpi_free( &ctx->RQ ); mbedtls_mpi_free( &ctx->RP ); mbedtls_mpi_free( &ctx->RN );
+ mbedtls_mpi_free( &ctx->QP ); mbedtls_mpi_free( &ctx->DQ ); mbedtls_mpi_free( &ctx->DP );
+ mbedtls_mpi_free( &ctx->Q ); mbedtls_mpi_free( &ctx->P ); mbedtls_mpi_free( &ctx->D );
+ mbedtls_mpi_free( &ctx->E ); mbedtls_mpi_free( &ctx->N );
+
+#if defined(MBEDTLS_THREADING_C)
+ mbedtls_mutex_free( &ctx->mutex );
+#endif
+}
+
+#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 RSA_DP "C1ACF567564274FB07A0BBAD5D26E298" \
+ "3C94D22288ACD763FD8E5600ED4A702D" \
+ "F84198A5F06C2E72236AE490C93F07F8" \
+ "3CC559CD27BC2D1CA488811730BB5725"
+
+#define RSA_DQ "4959CBF6F8FEF750AEE6977C155579C7" \
+ "D8AAEA56749EA28623272E4F7D0592AF" \
+ "7C1F1313CAC9471B5C523BFE592F517B" \
+ "407A1BD76C164B93DA2D32A383E58357"
+
+#define RSA_QP "9AE7FBC99546432DF71896FC239EADAE" \
+ "F38D18D2B2F0E2DD275AA977E2BF4411" \
+ "F5A3B2A5D33605AEBBCCBA7FEB9F2D2F" \
+ "A74206CEC169D74BF5A8C50D6F48EA08"
+
+#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_rsa_init( &rsa, MBEDTLS_RSA_PKCS_V15, 0 );
+
+ rsa.len = KEY_LEN;
+ MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &rsa.N , 16, RSA_N ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &rsa.E , 16, RSA_E ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &rsa.D , 16, RSA_D ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &rsa.P , 16, RSA_P ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &rsa.Q , 16, RSA_Q ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &rsa.DP, 16, RSA_DP ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &rsa.DQ, 16, RSA_DQ ) );
+ MBEDTLS_MPI_CHK( mbedtls_mpi_read_string( &rsa.QP, 16, RSA_QP ) );
+
+ 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" );
+
+ return( 1 );
+ }
+
+ 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" );
+
+ return( 1 );
+ }
+
+ 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" );
+
+ return( 1 );
+ }
+
+ if( memcmp( rsa_decrypted, rsa_plaintext, len ) != 0 )
+ {
+ if( verbose != 0 )
+ mbedtls_printf( "failed\n" );
+
+ return( 1 );
+ }
+
+ if( verbose != 0 )
+ mbedtls_printf( "passed\n" );
+
+#if defined(MBEDTLS_SHA1_C)
+ if( verbose != 0 )
+ mbedtls_printf( " PKCS#1 data sign : " );
+
+ mbedtls_sha1( rsa_plaintext, PT_LEN, sha1sum );
+
+ 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" );
+
+ return( 1 );
+ }
+
+ 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" );
+
+ return( 1 );
+ }
+
+ if( verbose != 0 )
+ mbedtls_printf( "passed\n" );
+#endif /* MBEDTLS_SHA1_C */
+
+ if( verbose != 0 )
+ mbedtls_printf( "\n" );
+
+cleanup:
+ mbedtls_rsa_free( &rsa );
+#else /* MBEDTLS_PKCS1_V15 */
+ ((void) verbose);
+#endif /* MBEDTLS_PKCS1_V15 */
+ return( ret );
+}
+
+#endif /* MBEDTLS_SELF_TEST */
+
+#endif /* MBEDTLS_RSA_C */