- Added support for PKCS#1 v2.1 encoding and thus support for the RSAES-OAEP and RSASSA-PSS operations (enabled by POLARSSL_PKCS1_V21)
diff --git a/library/rsa.c b/library/rsa.c index 77404fc..ec44d84 100644 --- a/library/rsa.c +++ b/library/rsa.c
@@ -34,6 +34,7 @@ #if defined(POLARSSL_RSA_C) #include "polarssl/rsa.h" +#include "polarssl/md.h" #include <stdlib.h> #include <string.h> @@ -291,6 +292,55 @@ 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 + * @param hlen length of the digest result + */ +static void mgf_mask( unsigned char *dst, int dlen, unsigned char *src, int slen, + md_context_t *md_ctx ) +{ + unsigned char mask[POLARSSL_MD_MAX_SIZE]; + unsigned char counter[4]; + unsigned char *p; + int i, use_len, hlen; + + 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 */ @@ -303,14 +353,22 @@ { int nb_pad, olen; unsigned char *p = output; +#if defined(POLARSSL_PKCS1_V21) + const md_info_t *md_info; + md_context_t md_ctx; + int i, hlen; +#endif olen = ctx->len; + if( f_rng == NULL ) + return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); + switch( ctx->padding ) { case RSA_PKCS_V15: - if( ilen < 0 || olen < ilen + 11 || f_rng == NULL ) + if( ilen < 0 || olen < ilen + 11 ) return( POLARSSL_ERR_RSA_BAD_INPUT_DATA ); nb_pad = olen - 3 - ilen; @@ -336,6 +394,50 @@ *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( ilen < 0 || 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 + // + for( i = 0; i < hlen; ++i ) + *p++ = (unsigned char) f_rng( p_rng ); + + // 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: @@ -359,6 +461,12 @@ int ret, ilen; unsigned char *p; unsigned char buf[1024]; +#if defined(POLARSSL_PKCS1_V21) + unsigned char lhash[POLARSSL_MD_MAX_SIZE]; + const md_info_t *md_info; + md_context_t md_ctx; + int hlen; +#endif ilen = ctx->len; @@ -390,6 +498,56 @@ 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 ); @@ -408,6 +566,8 @@ * Do an RSA operation to sign the message digest */ int rsa_pkcs1_sign( rsa_context *ctx, + int (*f_rng)(void *), + void *p_rng, int mode, int hash_id, int hashlen, @@ -416,6 +576,15 @@ { int nb_pad, olen; unsigned char *p = sig; +#if defined(POLARSSL_PKCS1_V21) + unsigned char salt[POLARSSL_MD_MAX_SIZE]; + const md_info_t *md_info; + md_context_t md_ctx; + int i, hlen, msb, offset = 0; +#else + (void) f_rng; + (void) p_rng; +#endif olen = ctx->len; @@ -468,63 +637,152 @@ 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 ); + 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 hlen + // + for( i = 0; i < hlen; ++i ) + salt[i] = (unsigned char) f_rng( p_rng ); + + // 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, hlen ); + p += hlen; + + // 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, hlen ); + 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 ); } - 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 ); - } - return( ( mode == RSA_PUBLIC ) ? rsa_public( ctx, sig, sig ) : rsa_private( ctx, sig, sig ) ); @@ -543,7 +801,12 @@ int ret, len, siglen; unsigned char *p, c; unsigned char buf[1024]; - +#if defined(POLARSSL_PKCS1_V21) + unsigned char zeros[8]; + const md_info_t *md_info; + md_context_t md_ctx; + int hlen, msb; +#endif siglen = ctx->len; if( siglen < 16 || siglen > (int) sizeof( buf ) ) @@ -572,67 +835,158 @@ p++; } p++; + + len = siglen - (int)( p - buf ); + + 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 ); + 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 ); + + // 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, hlen ); + md_finish( &md_ctx, p ); + + if( memcmp( p, p + hlen, hlen ) == 0 ) + return( 0 ); + else + return( POLARSSL_ERR_RSA_VERIFY_FAILED ); + break; +#endif + default: return( POLARSSL_ERR_RSA_INVALID_PADDING ); } - len = siglen - (int)( p - buf ); - - 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 ); - } - return( POLARSSL_ERR_RSA_INVALID_PADDING ); } @@ -789,7 +1143,7 @@ sha1( rsa_plaintext, PT_LEN, sha1sum ); - if( rsa_pkcs1_sign( &rsa, RSA_PRIVATE, SIG_RSA_SHA1, 20, + if( rsa_pkcs1_sign( &rsa, NULL, NULL, RSA_PRIVATE, SIG_RSA_SHA1, 20, sha1sum, rsa_ciphertext ) != 0 ) { if( verbose != 0 )