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Diffstat (limited to 'polarssl/src/library/rsa.c')
| -rw-r--r-- | polarssl/src/library/rsa.c | 1219 |
1 files changed, 1219 insertions, 0 deletions
diff --git a/polarssl/src/library/rsa.c b/polarssl/src/library/rsa.c new file mode 100644 index 0000000..72806e1 --- /dev/null +++ b/polarssl/src/library/rsa.c @@ -0,0 +1,1219 @@ +/* + * The RSA public-key cryptosystem + * + * Copyright (C) 2006-2011, Brainspark B.V. + * + * This file is part of PolarSSL (http://www.polarssl.org) + * Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org> + * + * All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ +/* + * RSA was designed by Ron Rivest, Adi Shamir and Len Adleman. + * + * http://theory.lcs.mit.edu/~rivest/rsapaper.pdf + * http://www.cacr.math.uwaterloo.ca/hac/about/chap8.pdf + */ + +#include "polarssl/config.h" + +#if defined(POLARSSL_RSA_C) + +#include "polarssl/rsa.h" +#include "polarssl/md.h" + +#include <stdlib.h> +#include <stdio.h> + +/* + * Initialize an RSA context + */ +void rsa_init( rsa_context *ctx, + int padding, + int hash_id ) +{ + memset( ctx, 0, sizeof( rsa_context ) ); + + ctx->padding = padding; + ctx->hash_id = hash_id; +} + +#if defined(POLARSSL_GENPRIME) + +/* + * Generate an RSA keypair + */ +int rsa_gen_key( rsa_context *ctx, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + unsigned int nbits, int exponent ) +{ + int ret; + mpi P1, Q1, H, G; + + if( f_rng == NULL || nbits < 128 || exponent < 3 ) + return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + + mpi_init( &P1 ); mpi_init( &Q1 ); mpi_init( &H ); mpi_init( &G ); + + /* + * find primes P and Q with Q < P so that: + * GCD( E, (P-1)*(Q-1) ) == 1 + */ + MPI_CHK( mpi_lset( &ctx->E, exponent ) ); + + do + { + MPI_CHK( mpi_gen_prime( &ctx->P, ( nbits + 1 ) >> 1, 0, + f_rng, p_rng ) ); + + MPI_CHK( mpi_gen_prime( &ctx->Q, ( nbits + 1 ) >> 1, 0, + f_rng, p_rng ) ); + + if( mpi_cmp_mpi( &ctx->P, &ctx->Q ) < 0 ) + mpi_swap( &ctx->P, &ctx->Q ); + + if( mpi_cmp_mpi( &ctx->P, &ctx->Q ) == 0 ) + continue; + + MPI_CHK( mpi_mul_mpi( &ctx->N, &ctx->P, &ctx->Q ) ); + if( mpi_msb( &ctx->N ) != nbits ) + continue; + + MPI_CHK( mpi_sub_int( &P1, &ctx->P, 1 ) ); + MPI_CHK( mpi_sub_int( &Q1, &ctx->Q, 1 ) ); + MPI_CHK( mpi_mul_mpi( &H, &P1, &Q1 ) ); + MPI_CHK( mpi_gcd( &G, &ctx->E, &H ) ); + } + while( 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 + */ + MPI_CHK( mpi_inv_mod( &ctx->D , &ctx->E, &H ) ); + MPI_CHK( mpi_mod_mpi( &ctx->DP, &ctx->D, &P1 ) ); + MPI_CHK( mpi_mod_mpi( &ctx->DQ, &ctx->D, &Q1 ) ); + MPI_CHK( mpi_inv_mod( &ctx->QP, &ctx->Q, &ctx->P ) ); + + ctx->len = ( mpi_msb( &ctx->N ) + 7 ) >> 3; + +cleanup: + + mpi_free( &P1 ); mpi_free( &Q1 ); mpi_free( &H ); mpi_free( &G ); + + if( ret != 0 ) + { + rsa_free( ctx ); + return( POLARSSL_ERR_RSA_KEY_GEN_FAILED + ret ); + } + + return( 0 ); +} + +#endif + +/* + * Check a public RSA key + */ +int rsa_check_pubkey( const rsa_context *ctx ) +{ + if( !ctx->N.p || !ctx->E.p ) + return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED ); + + if( ( ctx->N.p[0] & 1 ) == 0 || + ( ctx->E.p[0] & 1 ) == 0 ) + return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED ); + + if( mpi_msb( &ctx->N ) < 128 || + mpi_msb( &ctx->N ) > POLARSSL_MPI_MAX_BITS ) + return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED ); + + if( mpi_msb( &ctx->E ) < 2 || + mpi_msb( &ctx->E ) > 64 ) + return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED ); + + return( 0 ); +} + +/* + * Check a private RSA key + */ +int rsa_check_privkey( const rsa_context *ctx ) +{ + int ret; + mpi PQ, DE, P1, Q1, H, I, G, G2, L1, L2; + + if( ( ret = rsa_check_pubkey( ctx ) ) != 0 ) + return( ret ); + + if( !ctx->P.p || !ctx->Q.p || !ctx->D.p ) + return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED ); + + mpi_init( &PQ ); mpi_init( &DE ); mpi_init( &P1 ); mpi_init( &Q1 ); + mpi_init( &H ); mpi_init( &I ); mpi_init( &G ); mpi_init( &G2 ); + mpi_init( &L1 ); mpi_init( &L2 ); + + MPI_CHK( mpi_mul_mpi( &PQ, &ctx->P, &ctx->Q ) ); + MPI_CHK( mpi_mul_mpi( &DE, &ctx->D, &ctx->E ) ); + MPI_CHK( mpi_sub_int( &P1, &ctx->P, 1 ) ); + MPI_CHK( mpi_sub_int( &Q1, &ctx->Q, 1 ) ); + MPI_CHK( mpi_mul_mpi( &H, &P1, &Q1 ) ); + MPI_CHK( mpi_gcd( &G, &ctx->E, &H ) ); + + MPI_CHK( mpi_gcd( &G2, &P1, &Q1 ) ); + MPI_CHK( mpi_div_mpi( &L1, &L2, &H, &G2 ) ); + MPI_CHK( mpi_mod_mpi( &I, &DE, &L1 ) ); + + /* + * Check for a valid PKCS1v2 private key + */ + if( mpi_cmp_mpi( &PQ, &ctx->N ) != 0 || + mpi_cmp_int( &L2, 0 ) != 0 || + mpi_cmp_int( &I, 1 ) != 0 || + mpi_cmp_int( &G, 1 ) != 0 ) + { + ret = POLARSSL_ERR_RSA_KEY_CHECK_FAILED; + } + + +cleanup: + + mpi_free( &PQ ); mpi_free( &DE ); mpi_free( &P1 ); mpi_free( &Q1 ); + mpi_free( &H ); mpi_free( &I ); mpi_free( &G ); mpi_free( &G2 ); + mpi_free( &L1 ); mpi_free( &L2 ); + + if( ret == POLARSSL_ERR_RSA_KEY_CHECK_FAILED ) + return( ret ); + + if( ret != 0 ) + return( POLARSSL_ERR_RSA_KEY_CHECK_FAILED + ret ); + + return( 0 ); +} + +/* + * Do an RSA public key operation + */ +int rsa_public( rsa_context *ctx, + const unsigned char *input, + unsigned char *output ) +{ + int ret; + size_t olen; + mpi T; + + mpi_init( &T ); + + MPI_CHK( mpi_read_binary( &T, input, ctx->len ) ); + + if( mpi_cmp_mpi( &T, &ctx->N ) >= 0 ) + { + mpi_free( &T ); + return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + } + + olen = ctx->len; + MPI_CHK( mpi_exp_mod( &T, &T, &ctx->E, &ctx->N, &ctx->RN ) ); + MPI_CHK( mpi_write_binary( &T, output, olen ) ); + +cleanup: + + mpi_free( &T ); + + if( ret != 0 ) + return( POLARSSL_ERR_RSA_PUBLIC_FAILED + ret ); + + return( 0 ); +} + +/* + * Do an RSA private key operation + */ +int rsa_private( rsa_context *ctx, + const unsigned char *input, + unsigned char *output ) +{ + int ret; + size_t olen; + mpi T, T1, T2; + + mpi_init( &T ); mpi_init( &T1 ); mpi_init( &T2 ); + + MPI_CHK( mpi_read_binary( &T, input, ctx->len ) ); + + if( mpi_cmp_mpi( &T, &ctx->N ) >= 0 ) + { + mpi_free( &T ); + return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + } + +#if defined(POLARSSL_RSA_NO_CRT) + MPI_CHK( 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 + */ + MPI_CHK( mpi_exp_mod( &T1, &T, &ctx->DP, &ctx->P, &ctx->RP ) ); + MPI_CHK( mpi_exp_mod( &T2, &T, &ctx->DQ, &ctx->Q, &ctx->RQ ) ); + + /* + * T = (T1 - T2) * (Q^-1 mod P) mod P + */ + MPI_CHK( mpi_sub_mpi( &T, &T1, &T2 ) ); + MPI_CHK( mpi_mul_mpi( &T1, &T, &ctx->QP ) ); + MPI_CHK( mpi_mod_mpi( &T, &T1, &ctx->P ) ); + + /* + * output = T2 + T * Q + */ + MPI_CHK( mpi_mul_mpi( &T1, &T, &ctx->Q ) ); + MPI_CHK( mpi_add_mpi( &T, &T2, &T1 ) ); +#endif + + olen = ctx->len; + MPI_CHK( mpi_write_binary( &T, output, olen ) ); + +cleanup: + + mpi_free( &T ); mpi_free( &T1 ); mpi_free( &T2 ); + + if( ret != 0 ) + return( POLARSSL_ERR_RSA_PRIVATE_FAILED + ret ); + + return( 0 ); +} + +#if defined(POLARSSL_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, + md_context_t *md_ctx ) +{ + unsigned char mask[POLARSSL_MD_MAX_SIZE]; + unsigned char counter[4]; + unsigned char *p; + unsigned int hlen; + size_t i, use_len; + + memset( mask, 0, POLARSSL_MD_MAX_SIZE ); + memset( counter, 0, 4 ); + + hlen = md_ctx->md_info->size; + + // Generate and apply dbMask + // + p = dst; + + while( dlen > 0 ) + { + use_len = hlen; + if( dlen < hlen ) + use_len = dlen; + + md_starts( md_ctx ); + md_update( md_ctx, src, slen ); + md_update( md_ctx, counter, 4 ); + md_finish( md_ctx, mask ); + + for( i = 0; i < use_len; ++i ) + *p++ ^= mask[i]; + + counter[3]++; + + dlen -= use_len; + } +} +#endif + +/* + * Add the message padding, then do an RSA operation + */ +int rsa_pkcs1_encrypt( 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 defined(POLARSSL_PKCS1_V21) + unsigned int hlen; + const md_info_t *md_info; + md_context_t md_ctx; +#endif + + olen = ctx->len; + + if( f_rng == NULL ) + return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + + switch( ctx->padding ) + { + case RSA_PKCS_V15: + + if( olen < ilen + 11 ) + return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + + nb_pad = olen - 3 - ilen; + + *p++ = 0; + *p++ = 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 POLARSSL_ERR_RSA_RNG_FAILED + ret; + + p++; + } + *p++ = 0; + memcpy( p, input, ilen ); + break; + +#if defined(POLARSSL_PKCS1_V21) + case RSA_PKCS_V21: + + md_info = md_info_from_type( ctx->hash_id ); + if( md_info == NULL ) + return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + + hlen = md_get_size( md_info ); + + if( olen < ilen + 2 * hlen + 2 || f_rng == NULL ) + return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + + memset( output, 0, olen ); + memset( &md_ctx, 0, sizeof( md_context_t ) ); + + md_init_ctx( &md_ctx, md_info ); + + *p++ = 0; + + // Generate a random octet string seed + // + if( ( ret = f_rng( p_rng, p, hlen ) ) != 0 ) + return( POLARSSL_ERR_RSA_RNG_FAILED + ret ); + + p += hlen; + + // Construct DB + // + md( md_info, p, 0, p ); + p += hlen; + p += olen - 2 * hlen - 2 - ilen; + *p++ = 1; + memcpy( p, input, ilen ); + + // 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 ); + break; +#endif + + default: + + return( POLARSSL_ERR_RSA_INVALID_PADDING ); + } + + return( ( mode == RSA_PUBLIC ) + ? rsa_public( ctx, output, output ) + : rsa_private( ctx, output, output ) ); +} + +/* + * Do an RSA operation, then remove the message padding + */ +int rsa_pkcs1_decrypt( rsa_context *ctx, + int mode, size_t *olen, + const unsigned char *input, + unsigned char *output, + size_t output_max_len) +{ + int ret; + size_t ilen; + unsigned char *p; + unsigned char buf[1024]; +#if defined(POLARSSL_PKCS1_V21) + unsigned char lhash[POLARSSL_MD_MAX_SIZE]; + unsigned int hlen; + const md_info_t *md_info; + md_context_t md_ctx; +#endif + + ilen = ctx->len; + + if( ilen < 16 || ilen > sizeof( buf ) ) + return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + + ret = ( mode == RSA_PUBLIC ) + ? rsa_public( ctx, input, buf ) + : rsa_private( ctx, input, buf ); + + if( ret != 0 ) + return( ret ); + + p = buf; + + switch( ctx->padding ) + { + case RSA_PKCS_V15: + + if( *p++ != 0 || *p++ != RSA_CRYPT ) + return( POLARSSL_ERR_RSA_INVALID_PADDING ); + + while( *p != 0 ) + { + if( p >= buf + ilen - 1 ) + return( POLARSSL_ERR_RSA_INVALID_PADDING ); + p++; + } + p++; + break; + +#if defined(POLARSSL_PKCS1_V21) + case RSA_PKCS_V21: + + if( *p++ != 0 ) + return( POLARSSL_ERR_RSA_INVALID_PADDING ); + + md_info = md_info_from_type( ctx->hash_id ); + if( md_info == NULL ) + return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + + hlen = md_get_size( md_info ); + memset( &md_ctx, 0, sizeof( md_context_t ) ); + + md_init_ctx( &md_ctx, md_info ); + + // Generate lHash + // + md( md_info, lhash, 0, 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 ); + + p += hlen; + + // Check validity + // + if( memcmp( lhash, p, hlen ) != 0 ) + return( POLARSSL_ERR_RSA_INVALID_PADDING ); + + p += hlen; + + while( *p == 0 && p < buf + ilen ) + p++; + + if( p == buf + ilen ) + return( POLARSSL_ERR_RSA_INVALID_PADDING ); + + if( *p++ != 0x01 ) + return( POLARSSL_ERR_RSA_INVALID_PADDING ); + + break; +#endif + + default: + + return( POLARSSL_ERR_RSA_INVALID_PADDING ); + } + + if (ilen - (p - buf) > output_max_len) + return( POLARSSL_ERR_RSA_OUTPUT_TOO_LARGE ); + + *olen = ilen - (p - buf); + memcpy( output, p, *olen ); + + return( 0 ); +} + +/* + * Do an RSA operation to sign the message digest + */ +int rsa_pkcs1_sign( rsa_context *ctx, + int (*f_rng)(void *, unsigned char *, size_t), + void *p_rng, + int mode, + int hash_id, + unsigned int hashlen, + const unsigned char *hash, + unsigned char *sig ) +{ + size_t nb_pad, olen; + unsigned char *p = sig; +#if defined(POLARSSL_PKCS1_V21) + unsigned char salt[POLARSSL_MD_MAX_SIZE]; + unsigned int slen, hlen, offset = 0; + int ret; + size_t msb; + const md_info_t *md_info; + md_context_t md_ctx; +#else + (void) f_rng; + (void) p_rng; +#endif + + olen = ctx->len; + + switch( ctx->padding ) + { + case RSA_PKCS_V15: + + switch( hash_id ) + { + case SIG_RSA_RAW: + nb_pad = olen - 3 - hashlen; + break; + + case SIG_RSA_MD2: + case SIG_RSA_MD4: + case SIG_RSA_MD5: + nb_pad = olen - 3 - 34; + break; + + case SIG_RSA_SHA1: + nb_pad = olen - 3 - 35; + break; + + case SIG_RSA_SHA224: + nb_pad = olen - 3 - 47; + break; + + case SIG_RSA_SHA256: + nb_pad = olen - 3 - 51; + break; + + case SIG_RSA_SHA384: + nb_pad = olen - 3 - 67; + break; + + case SIG_RSA_SHA512: + nb_pad = olen - 3 - 83; + break; + + + default: + return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + } + + if( nb_pad < 8 ) + return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + + *p++ = 0; + *p++ = RSA_SIGN; + memset( p, 0xFF, nb_pad ); + p += nb_pad; + *p++ = 0; + + switch( hash_id ) + { + case SIG_RSA_RAW: + memcpy( p, hash, hashlen ); + break; + + case SIG_RSA_MD2: + memcpy( p, ASN1_HASH_MDX, 18 ); + memcpy( p + 18, hash, 16 ); + p[13] = 2; break; + + case SIG_RSA_MD4: + memcpy( p, ASN1_HASH_MDX, 18 ); + memcpy( p + 18, hash, 16 ); + p[13] = 4; break; + + case SIG_RSA_MD5: + memcpy( p, ASN1_HASH_MDX, 18 ); + memcpy( p + 18, hash, 16 ); + p[13] = 5; break; + + case SIG_RSA_SHA1: + memcpy( p, ASN1_HASH_SHA1, 15 ); + memcpy( p + 15, hash, 20 ); + break; + + case SIG_RSA_SHA224: + memcpy( p, ASN1_HASH_SHA2X, 19 ); + memcpy( p + 19, hash, 28 ); + p[1] += 28; p[14] = 4; p[18] += 28; break; + + case SIG_RSA_SHA256: + memcpy( p, ASN1_HASH_SHA2X, 19 ); + memcpy( p + 19, hash, 32 ); + p[1] += 32; p[14] = 1; p[18] += 32; break; + + case SIG_RSA_SHA384: + memcpy( p, ASN1_HASH_SHA2X, 19 ); + memcpy( p + 19, hash, 48 ); + p[1] += 48; p[14] = 2; p[18] += 48; break; + + case SIG_RSA_SHA512: + memcpy( p, ASN1_HASH_SHA2X, 19 ); + memcpy( p + 19, hash, 64 ); + p[1] += 64; p[14] = 3; p[18] += 64; break; + + default: + return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + } + + break; + +#if defined(POLARSSL_PKCS1_V21) + case RSA_PKCS_V21: + + if( f_rng == NULL ) + return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + + switch( hash_id ) + { + case SIG_RSA_MD2: + case SIG_RSA_MD4: + case SIG_RSA_MD5: + hashlen = 16; + break; + + case SIG_RSA_SHA1: + hashlen = 20; + break; + + case SIG_RSA_SHA224: + hashlen = 28; + break; + + case SIG_RSA_SHA256: + hashlen = 32; + break; + + case SIG_RSA_SHA384: + hashlen = 48; + break; + + case SIG_RSA_SHA512: + hashlen = 64; + break; + + default: + return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + } + + md_info = md_info_from_type( ctx->hash_id ); + if( md_info == NULL ) + return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + + hlen = md_get_size( md_info ); + slen = hlen; + + memset( sig, 0, olen ); + memset( &md_ctx, 0, sizeof( md_context_t ) ); + + md_init_ctx( &md_ctx, md_info ); + + msb = mpi_msb( &ctx->N ) - 1; + + // Generate salt of length slen + // + if( ( ret = f_rng( p_rng, salt, slen ) ) != 0 ) + return( POLARSSL_ERR_RSA_RNG_FAILED + ret ); + + // Note: EMSA-PSS encoding is over the length of N - 1 bits + // + msb = mpi_msb( &ctx->N ) - 1; + p += olen - hlen * 2 - 2; + *p++ = 0x01; + memcpy( p, salt, slen ); + p += slen; + + // Generate H = Hash( M' ) + // + md_starts( &md_ctx ); + md_update( &md_ctx, p, 8 ); + md_update( &md_ctx, hash, hashlen ); + md_update( &md_ctx, salt, slen ); + 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 ); + + msb = mpi_msb( &ctx->N ) - 1; + sig[0] &= 0xFF >> ( olen * 8 - msb ); + + p += hlen; + *p++ = 0xBC; + break; +#endif + + default: + + return( POLARSSL_ERR_RSA_INVALID_PADDING ); + } + + return( ( mode == RSA_PUBLIC ) + ? rsa_public( ctx, sig, sig ) + : rsa_private( ctx, sig, sig ) ); +} + +/* + * Do an RSA operation and check the message digest + */ +int rsa_pkcs1_verify( rsa_context *ctx, + int mode, + int hash_id, + unsigned int hashlen, + const unsigned char *hash, + unsigned char *sig ) +{ + int ret; + size_t len, siglen; + unsigned char *p, c; + unsigned char buf[1024]; +#if defined(POLARSSL_PKCS1_V21) + unsigned char result[POLARSSL_MD_MAX_SIZE]; + unsigned char zeros[8]; + unsigned int hlen; + size_t slen, msb; + const md_info_t *md_info; + md_context_t md_ctx; +#endif + siglen = ctx->len; + + if( siglen < 16 || siglen > sizeof( buf ) ) + return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + + ret = ( mode == RSA_PUBLIC ) + ? rsa_public( ctx, sig, buf ) + : rsa_private( ctx, sig, buf ); + + if( ret != 0 ) + return( ret ); + + p = buf; + + switch( ctx->padding ) + { + case RSA_PKCS_V15: + + if( *p++ != 0 || *p++ != RSA_SIGN ) + return( POLARSSL_ERR_RSA_INVALID_PADDING ); + + while( *p != 0 ) + { + if( p >= buf + siglen - 1 || *p != 0xFF ) + return( POLARSSL_ERR_RSA_INVALID_PADDING ); + p++; + } + p++; + + len = siglen - ( p - buf ); + + if( len == 33 && hash_id == SIG_RSA_SHA1 ) + { + if( memcmp( p, ASN1_HASH_SHA1_ALT, 13 ) == 0 && + memcmp( p + 13, hash, 20 ) == 0 ) + return( 0 ); + else + return( POLARSSL_ERR_RSA_VERIFY_FAILED ); + } + if( len == 34 ) + { + c = p[13]; + p[13] = 0; + + if( memcmp( p, ASN1_HASH_MDX, 18 ) != 0 ) + return( POLARSSL_ERR_RSA_VERIFY_FAILED ); + + if( ( c == 2 && hash_id == SIG_RSA_MD2 ) || + ( c == 4 && hash_id == SIG_RSA_MD4 ) || + ( c == 5 && hash_id == SIG_RSA_MD5 ) ) + { + if( memcmp( p + 18, hash, 16 ) == 0 ) + return( 0 ); + else + return( POLARSSL_ERR_RSA_VERIFY_FAILED ); + } + } + + if( len == 35 && hash_id == SIG_RSA_SHA1 ) + { + if( memcmp( p, ASN1_HASH_SHA1, 15 ) == 0 && + memcmp( p + 15, hash, 20 ) == 0 ) + return( 0 ); + else + return( POLARSSL_ERR_RSA_VERIFY_FAILED ); + } + if( ( len == 19 + 28 && p[14] == 4 && hash_id == SIG_RSA_SHA224 ) || + ( len == 19 + 32 && p[14] == 1 && hash_id == SIG_RSA_SHA256 ) || + ( len == 19 + 48 && p[14] == 2 && hash_id == SIG_RSA_SHA384 ) || + ( len == 19 + 64 && p[14] == 3 && hash_id == SIG_RSA_SHA512 ) ) + { + c = p[1] - 17; + p[1] = 17; + p[14] = 0; + + if( p[18] == c && + memcmp( p, ASN1_HASH_SHA2X, 18 ) == 0 && + memcmp( p + 19, hash, c ) == 0 ) + return( 0 ); + else + return( POLARSSL_ERR_RSA_VERIFY_FAILED ); + } + + if( len == hashlen && hash_id == SIG_RSA_RAW ) + { + if( memcmp( p, hash, hashlen ) == 0 ) + return( 0 ); + else + return( POLARSSL_ERR_RSA_VERIFY_FAILED ); + } + + break; + +#if defined(POLARSSL_PKCS1_V21) + case RSA_PKCS_V21: + + if( buf[siglen - 1] != 0xBC ) + return( POLARSSL_ERR_RSA_INVALID_PADDING ); + + switch( hash_id ) + { + case SIG_RSA_MD2: + case SIG_RSA_MD4: + case SIG_RSA_MD5: + hashlen = 16; + break; + + case SIG_RSA_SHA1: + hashlen = 20; + break; + + case SIG_RSA_SHA224: + hashlen = 28; + break; + + case SIG_RSA_SHA256: + hashlen = 32; + break; + + case SIG_RSA_SHA384: + hashlen = 48; + break; + + case SIG_RSA_SHA512: + hashlen = 64; + break; + + default: + return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + } + + md_info = md_info_from_type( ctx->hash_id ); + if( md_info == NULL ) + return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + + hlen = md_get_size( md_info ); + slen = siglen - hlen - 1; + + memset( &md_ctx, 0, sizeof( md_context_t ) ); + memset( zeros, 0, 8 ); + + md_init_ctx( &md_ctx, md_info ); + + // Note: EMSA-PSS verification is over the length of N - 1 bits + // + msb = mpi_msb( &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( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + + mgf_mask( p, siglen - hlen - 1, p + siglen - hlen - 1, hlen, &md_ctx ); + + buf[0] &= 0xFF >> ( siglen * 8 - msb ); + + while( *p == 0 && p < buf + siglen ) + p++; + + if( p == buf + siglen ) + return( POLARSSL_ERR_RSA_INVALID_PADDING ); + + if( *p++ != 0x01 ) + return( POLARSSL_ERR_RSA_INVALID_PADDING ); + + slen -= p - buf; + + // Generate H = Hash( M' ) + // + md_starts( &md_ctx ); + md_update( &md_ctx, zeros, 8 ); + md_update( &md_ctx, hash, hashlen ); + md_update( &md_ctx, p, slen ); + md_finish( &md_ctx, result ); + + if( memcmp( p + slen, result, hlen ) == 0 ) + return( 0 ); + else + return( POLARSSL_ERR_RSA_VERIFY_FAILED ); +#endif + + default: + + return( POLARSSL_ERR_RSA_INVALID_PADDING ); + } + + return( POLARSSL_ERR_RSA_INVALID_PADDING ); +} + +/* + * Free the components of an RSA key + */ +void rsa_free( rsa_context *ctx ) +{ + mpi_free( &ctx->RQ ); mpi_free( &ctx->RP ); mpi_free( &ctx->RN ); + mpi_free( &ctx->QP ); mpi_free( &ctx->DQ ); mpi_free( &ctx->DP ); + mpi_free( &ctx->Q ); mpi_free( &ctx->P ); mpi_free( &ctx->D ); + mpi_free( &ctx->E ); mpi_free( &ctx->N ); +} + +#if defined(POLARSSL_SELF_TEST) + +#include "polarssl/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" + +static int myrand( void *rng_state, unsigned char *output, size_t len ) +{ + size_t i; + + if( rng_state != NULL ) + rng_state = NULL; + + for( i = 0; i < len; ++i ) + output[i] = rand(); + + return( 0 ); +} + +/* + * Checkup routine + */ +int rsa_self_test( int verbose ) +{ + size_t len; + rsa_context rsa; + unsigned char rsa_plaintext[PT_LEN]; + unsigned char rsa_decrypted[PT_LEN]; + unsigned char rsa_ciphertext[KEY_LEN]; +#if defined(POLARSSL_SHA1_C) + unsigned char sha1sum[20]; +#endif + + rsa_init( &rsa, RSA_PKCS_V15, 0 ); + + rsa.len = KEY_LEN; + mpi_read_string( &rsa.N , 16, RSA_N ); + mpi_read_string( &rsa.E , 16, RSA_E ); + mpi_read_string( &rsa.D , 16, RSA_D ); + mpi_read_string( &rsa.P , 16, RSA_P ); + mpi_read_string( &rsa.Q , 16, RSA_Q ); + mpi_read_string( &rsa.DP, 16, RSA_DP ); + mpi_read_string( &rsa.DQ, 16, RSA_DQ ); + mpi_read_string( &rsa.QP, 16, RSA_QP ); + + if( verbose != 0 ) + printf( " RSA key validation: " ); + + if( rsa_check_pubkey( &rsa ) != 0 || + rsa_check_privkey( &rsa ) != 0 ) + { + if( verbose != 0 ) + printf( "failed\n" ); + + return( 1 ); + } + + if( verbose != 0 ) + printf( "passed\n PKCS#1 encryption : " ); + + memcpy( rsa_plaintext, RSA_PT, PT_LEN ); + + if( rsa_pkcs1_encrypt( &rsa, &myrand, NULL, RSA_PUBLIC, PT_LEN, + rsa_plaintext, rsa_ciphertext ) != 0 ) + { + if( verbose != 0 ) + printf( "failed\n" ); + + return( 1 ); + } + + if( verbose != 0 ) + printf( "passed\n PKCS#1 decryption : " ); + + if( rsa_pkcs1_decrypt( &rsa, RSA_PRIVATE, &len, + rsa_ciphertext, rsa_decrypted, + sizeof(rsa_decrypted) ) != 0 ) + { + if( verbose != 0 ) + printf( "failed\n" ); + + return( 1 ); + } + + if( memcmp( rsa_decrypted, rsa_plaintext, len ) != 0 ) + { + if( verbose != 0 ) + printf( "failed\n" ); + + return( 1 ); + } + +#if defined(POLARSSL_SHA1_C) + if( verbose != 0 ) + printf( "passed\n PKCS#1 data sign : " ); + + sha1( rsa_plaintext, PT_LEN, sha1sum ); + + if( rsa_pkcs1_sign( &rsa, NULL, NULL, RSA_PRIVATE, SIG_RSA_SHA1, 20, + sha1sum, rsa_ciphertext ) != 0 ) + { + if( verbose != 0 ) + printf( "failed\n" ); + + return( 1 ); + } + + if( verbose != 0 ) + printf( "passed\n PKCS#1 sig. verify: " ); + + if( rsa_pkcs1_verify( &rsa, RSA_PUBLIC, SIG_RSA_SHA1, 20, + sha1sum, rsa_ciphertext ) != 0 ) + { + if( verbose != 0 ) + printf( "failed\n" ); + + return( 1 ); + } + + if( verbose != 0 ) + printf( "passed\n\n" ); +#endif /* POLARSSL_SHA1_C */ + + rsa_free( &rsa ); + + return( 0 ); +} + +#endif + +#endif |