diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h index af8aa0d06..e9a15262e 100644 --- a/include/mbedtls/config.h +++ b/include/mbedtls/config.h @@ -2970,6 +2970,18 @@ */ //#define MBEDTLS_MEMORY_BUFFER_ALLOC_C +/** + * \def MBEDTLS_PLATFORM_FAULT_CALLBACKS + * + * Uncomment to provide your own alternate implementation for mbedtls_platform_fault(), + * used in library/platform_util.c to signal a fault injection in either + * mbedtls_platform_memcpy or mbedtls_platform_memset. + * + * You will need to provide a header "platform_fault.h" and an implementation at + * compile time. + */ +//#define MBEDTLS_PLATFORM_FAULT_CALLBACKS + /** * \def MBEDTLS_NET_C * diff --git a/include/mbedtls/platform_util.h b/include/mbedtls/platform_util.h index e0bd08c36..4999500ce 100644 --- a/include/mbedtls/platform_util.h +++ b/include/mbedtls/platform_util.h @@ -276,9 +276,9 @@ uint32_t mbedtls_platform_random_uint32( void ); * cryptographically secure RNG, but provide an RNG for utility * functions. * - * \note If the given range is [0, 0), 0 is returned. - * * \param num Max-value for the generated random number, exclusive. + * Must be greater than zero, otherwise an undefined behavior + * will occur on "num % 0". * The generated number will be on range [0, num). * * \return The generated random number. diff --git a/library/ccm.c b/library/ccm.c index e54a9955b..aa15af2ea 100644 --- a/library/ccm.c +++ b/library/ccm.c @@ -114,6 +114,41 @@ void mbedtls_ccm_free( mbedtls_ccm_context *ctx ) mbedtls_platform_zeroize( ctx, sizeof( mbedtls_ccm_context ) ); } +/* Durstenfeld's version of Fisher-Yates shuffle */ +static void mbedtls_generate_permutation( unsigned char* table, size_t size ) +{ + size_t i, j; + + for( i = 0; i < size; i++ ) + { + table[i] = (unsigned char) i; + } + + if( size < 2 ) + { + return; + } + + for( i = size - 1; i > 0; i-- ) + { + unsigned char tmp; + j = mbedtls_platform_random_in_range( (uint32_t) i + 1 ); + tmp = table[i]; + table[i] = table[j]; + table[j] = tmp; + } +} + +static void mbedtls_generate_masks( unsigned char* table, size_t size ) +{ + size_t i; + + for( i = 0; i < size; i++ ) + { + table[i] = mbedtls_platform_random_in_range( 256 ); + } +} + /* * Macros for common operations. * Results in smaller compiled code than static inline functions. @@ -122,30 +157,55 @@ void mbedtls_ccm_free( mbedtls_ccm_context *ctx ) /* * Update the CBC-MAC state in y using a block in b * (Always using b as the source helps the compiler optimise a bit better.) + * Initial b masking happens outside of this macro due to various sources of it. */ #define UPDATE_CBC_MAC \ for( i = 0; i < 16; i++ ) \ - y[i] ^= b[i]; \ + { \ + y[perm_table[i]] ^= b[perm_table[i]]; \ + y[perm_table[i]] ^= mask_table[perm_table[i]]; \ + } \ \ if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, y, 16, y, &olen ) ) != 0 ) \ return( ret ); +/* + * Copy src to dst starting at a random offset, while masking the whole dst buffer. + */ +#define COPY_MASK( dst, src, mask, len_src, len_dst ) \ + do \ + { \ + unsigned j, offset = mbedtls_platform_random_in_range( 256 ); \ + for( i = 0; i < len_src; i++ ) \ + { \ + j = (i + offset) % len_src; \ + (dst)[j] = (src)[j] ^ (mask)[j]; \ + } \ + for( ; i < len_dst; i++ ) \ + (dst)[i] ^= (mask)[i]; \ + } while( 0 ) /* * Encrypt or decrypt a partial block with CTR * Warning: using b for temporary storage! src and dst must not be b! * This avoids allocating one more 16 bytes buffer while allowing src == dst. */ -#define CTR_CRYPT( dst, src, len ) \ +#define CTR_CRYPT( dst, src, len ) \ do \ { \ + mbedtls_generate_permutation( perm_table, len ); \ + mbedtls_generate_masks( mask_table, len ); \ if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, ctr, \ 16, b, &olen ) ) != 0 ) \ { \ return( ret ); \ } \ \ - for( i = 0; i < (len); i++ ) \ - (dst)[i] = (src)[i] ^ b[i]; \ + for( i = 0; i < len; i++ ) \ + { \ + (dst)[perm_table[i]] = (src)[perm_table[i]] ^ mask_table[perm_table[i]];\ + (dst)[perm_table[i]] ^= b[perm_table[i]]; \ + (dst)[perm_table[i]] ^= mask_table[perm_table[i]]; \ + } \ } while( 0 ) /* @@ -164,6 +224,8 @@ static int ccm_auth_crypt( mbedtls_ccm_context *ctx, int mode, size_t length, unsigned char b[16]; unsigned char y[16]; unsigned char ctr[16]; + unsigned char perm_table[16]; + unsigned char mask_table[16]; const unsigned char *src; unsigned char *dst; @@ -184,6 +246,10 @@ static int ccm_auth_crypt( mbedtls_ccm_context *ctx, int mode, size_t length, if( add_len > 0xFF00 ) return( MBEDTLS_ERR_CCM_BAD_INPUT ); + mbedtls_platform_zeroize( b, 16 ); + mbedtls_platform_zeroize( y, 16 ); + mbedtls_platform_zeroize( ctr, 16 ); + q = (uint_fast8_t) (16 - 1 - iv_len); /* @@ -198,15 +264,16 @@ static int ccm_auth_crypt( mbedtls_ccm_context *ctx, int mode, size_t length, * 5 .. 3 (t - 2) / 2 * 2 .. 0 q - 1 */ - b[0] = 0; - b[0] |= ( add_len > 0 ) << 6; - b[0] |= ( ( tag_len - 2 ) / 2 ) << 3; - b[0] |= q - 1; - - mbedtls_platform_memcpy( b + 1, iv, iv_len ); + mbedtls_generate_masks( mask_table, 16 ); + mbedtls_generate_permutation( perm_table, 16 ); + b[0] = (unsigned char) ( ( ( add_len > 0 ) << 6 ) | + ( ( ( tag_len - 2 ) / 2 ) << 3 ) | + ( q - 1 ) ) ^ mask_table[0]; + for( i = 0; i < iv_len; i++ ) + b[i+1] = iv[i] ^ mask_table[i+1]; for( i = 0, len_left = length; i < q; i++, len_left >>= 8 ) - b[15-i] = (unsigned char)( len_left & 0xFF ); + b[15-i] = (unsigned char)( ( len_left & 0xFF ) ) ^ mask_table[15-i]; if( len_left > 0 ) return( MBEDTLS_ERR_CCM_BAD_INPUT ); @@ -226,12 +293,16 @@ static int ccm_auth_crypt( mbedtls_ccm_context *ctx, int mode, size_t length, len_left = add_len; src = add; + mbedtls_generate_masks( mask_table, 16 ); + mbedtls_generate_permutation( perm_table, 16 ); mbedtls_platform_memset( b, 0, 16 ); - b[0] = (unsigned char)( ( add_len >> 8 ) & 0xFF ); - b[1] = (unsigned char)( ( add_len ) & 0xFF ); + b[0] = (unsigned char)( ( ( add_len >> 8 ) & 0xFF ) ^ mask_table[0] ); + b[1] = (unsigned char)( ( ( add_len ) & 0xFF ) ^ mask_table[1] ); use_len = len_left < 16 - 2 ? len_left : 16 - 2; - mbedtls_platform_memcpy( b + 2, src, use_len ); + + COPY_MASK( b+2, src, mask_table+2, use_len, 14 ); + len_left -= use_len; src += use_len; @@ -239,10 +310,12 @@ static int ccm_auth_crypt( mbedtls_ccm_context *ctx, int mode, size_t length, while( len_left > 0 ) { + mbedtls_generate_masks( mask_table, 16 ); + mbedtls_generate_permutation( perm_table, 16 ); use_len = len_left > 16 ? 16 : len_left; mbedtls_platform_memset( b, 0, 16 ); - mbedtls_platform_memcpy( b, src, use_len ); + COPY_MASK( b, src, mask_table, use_len, 16); UPDATE_CBC_MAC; len_left -= use_len; @@ -281,8 +354,10 @@ static int ccm_auth_crypt( mbedtls_ccm_context *ctx, int mode, size_t length, if( mode == CCM_ENCRYPT ) { + mbedtls_generate_masks( mask_table, 16 ); + mbedtls_generate_permutation( perm_table, 16 ); mbedtls_platform_memset( b, 0, 16 ); - mbedtls_platform_memcpy( b, src, use_len ); + COPY_MASK( b, src, mask_table, use_len, 16 ); UPDATE_CBC_MAC; } @@ -290,8 +365,10 @@ static int ccm_auth_crypt( mbedtls_ccm_context *ctx, int mode, size_t length, if( mode == CCM_DECRYPT ) { + mbedtls_generate_masks( mask_table, 16 ); + mbedtls_generate_permutation( perm_table, 16 ); mbedtls_platform_memset( b, 0, 16 ); - mbedtls_platform_memcpy( b, dst, use_len ); + COPY_MASK( b, dst, mask_table, use_len, 16 ); UPDATE_CBC_MAC; } @@ -317,6 +394,10 @@ static int ccm_auth_crypt( mbedtls_ccm_context *ctx, int mode, size_t length, CTR_CRYPT( y, y, 16 ); mbedtls_platform_memcpy( tag, y, tag_len ); + mbedtls_platform_zeroize( b, 16 ); + mbedtls_platform_zeroize( y, 16 ); + mbedtls_platform_zeroize( ctr, 16 ); + return( ret ); } diff --git a/library/platform_util.c b/library/platform_util.c index 15309aa7e..ecfdb84d1 100644 --- a/library/platform_util.c +++ b/library/platform_util.c @@ -48,6 +48,12 @@ #include "mbedtls/entropy_poll.h" #endif +#if defined(MBEDTLS_PLATFORM_FAULT_CALLBACKS) +#include "platform_fault.h" +#else +static void mbedtls_platform_fault(){} +#endif + #include #include @@ -119,43 +125,45 @@ void *mbedtls_platform_zeroize( void *buf, size_t len ) void *mbedtls_platform_memset( void *ptr, int value, size_t num ) { - size_t i, start_offset; + size_t i, start_offset = 0; volatile size_t flow_counter = 0; volatile char *b = ptr; char rnd_data; - - start_offset = (size_t) mbedtls_platform_random_in_range( (uint32_t) num ); - rnd_data = (char) mbedtls_platform_random_in_range( 256 ); - - /* Perform a memset operations with random data and start from a random - * location */ - for( i = start_offset; i < num; ++i ) + if( num > 0 ) { - b[i] = rnd_data; - flow_counter++; - } + start_offset = (size_t) mbedtls_platform_random_in_range( (uint32_t) num ); - /* Start from a random location with target data */ - for( i = start_offset; i < num; ++i ) - { - b[i] = value; - flow_counter++; - } + rnd_data = (char) mbedtls_platform_random_in_range( 256 ); - /* Second memset operation with random data */ - for( i = 0; i < start_offset; ++i ) - { - b[i] = rnd_data; - flow_counter++; - } + /* Perform a memset operations with random data and start from a random + * location */ + for( i = start_offset; i < num; ++i ) + { + b[i] = rnd_data; + flow_counter++; + } - /* Finish memset operation with correct data */ - for( i = 0; i < start_offset; ++i ) - { - b[i] = value; - flow_counter++; - } + /* Start from a random location with target data */ + for( i = start_offset; i < num; ++i ) + { + b[i] = value; + flow_counter++; + } + /* Second memset operation with random data */ + for( i = 0; i < start_offset; ++i ) + { + b[i] = rnd_data; + flow_counter++; + } + + /* Finish memset operation with correct data */ + for( i = 0; i < start_offset; ++i ) + { + b[i] = value; + flow_counter++; + } + } /* check the correct number of iterations */ if( flow_counter == 2 * num ) { @@ -165,6 +173,7 @@ void *mbedtls_platform_memset( void *ptr, int value, size_t num ) return ptr; } } + mbedtls_platform_fault(); return NULL; } @@ -204,6 +213,7 @@ void *mbedtls_platform_memcpy( void *dst, const void *src, size_t num ) return dst; } } + mbedtls_platform_fault(); return NULL; } @@ -245,22 +255,25 @@ int mbedtls_platform_memequal( const void *buf1, const void *buf2, size_t num ) /* Start from a random location and check the correct number of iterations */ size_t i, flow_counter = 0; - size_t start_offset = (size_t) mbedtls_platform_random_in_range( (uint32_t) num ); - - for( i = start_offset; i < num; i++ ) + size_t start_offset = 0; + if( num > 0 ) { - unsigned char x = A[i], y = B[i]; - flow_counter++; - diff |= x ^ y; - } + start_offset = (size_t) mbedtls_platform_random_in_range( (uint32_t) num ); - for( i = 0; i < start_offset; i++ ) - { - unsigned char x = A[i], y = B[i]; - flow_counter++; - diff |= x ^ y; - } + for( i = start_offset; i < num; i++ ) + { + unsigned char x = A[i], y = B[i]; + flow_counter++; + diff |= x ^ y; + } + for( i = 0; i < start_offset; i++ ) + { + unsigned char x = A[i], y = B[i]; + flow_counter++; + diff |= x ^ y; + } + } /* Return 0 only when diff is 0 and flow_counter is equal to num */ return( (int) diff | (int) ( flow_counter ^ num ) ); } @@ -340,18 +353,7 @@ void mbedtls_platform_random_buf( uint8_t *buf, size_t len ) uint32_t mbedtls_platform_random_in_range( uint32_t num ) { - uint32_t result; - - if( num <= 1 ) - { - result = 0; - } - else - { - result = mbedtls_platform_random_uint32() % num; - } - - return( result ); + return mbedtls_platform_random_uint32() % num; } void mbedtls_platform_random_delay( void ) diff --git a/library/ssl_tls.c b/library/ssl_tls.c index b0dabf2dd..a33760fdf 100644 --- a/library/ssl_tls.c +++ b/library/ssl_tls.c @@ -933,8 +933,8 @@ int tls_prf_generic( mbedtls_md_type_t md_type, { size_t nb; size_t i, j, k, md_len; - unsigned char tmp[128]; - unsigned char h_i[MBEDTLS_MD_MAX_SIZE]; + unsigned char tmp[128] = {0}; + unsigned char h_i[MBEDTLS_MD_MAX_SIZE] = {0}; mbedtls_md_handle_t md_info; mbedtls_md_context_t md_ctx; int ret; @@ -12709,6 +12709,7 @@ void mbedtls_ssl_free( mbedtls_ssl_context *ssl ) #endif mbedtls_platform_zeroize( ssl->out_buf, out_buf_len ); mbedtls_free( ssl->out_buf ); + ssl->out_buf = NULL; } if( ssl->in_buf != NULL ) @@ -12720,6 +12721,7 @@ void mbedtls_ssl_free( mbedtls_ssl_context *ssl ) #endif mbedtls_platform_zeroize( ssl->in_buf, in_buf_len ); mbedtls_free( ssl->in_buf ); + ssl->in_buf = NULL; } #if defined(MBEDTLS_ZLIB_SUPPORT) diff --git a/library/version_features.c b/library/version_features.c index b8f1d263d..d7e65812e 100644 --- a/library/version_features.c +++ b/library/version_features.c @@ -732,6 +732,9 @@ static const char *features[] = { #if defined(MBEDTLS_MEMORY_BUFFER_ALLOC_C) "MBEDTLS_MEMORY_BUFFER_ALLOC_C", #endif /* MBEDTLS_MEMORY_BUFFER_ALLOC_C */ +#if defined(MBEDTLS_PLATFORM_FAULT_CALLBACKS) + "MBEDTLS_PLATFORM_FAULT_CALLBACKS", +#endif /* MBEDTLS_PLATFORM_FAULT_CALLBACKS */ #if defined(MBEDTLS_NET_C) "MBEDTLS_NET_C", #endif /* MBEDTLS_NET_C */ diff --git a/programs/ssl/query_config.c b/programs/ssl/query_config.c index ecf951ed6..580eaf396 100644 --- a/programs/ssl/query_config.c +++ b/programs/ssl/query_config.c @@ -1994,6 +1994,14 @@ int query_config( const char *config ) } #endif /* MBEDTLS_MEMORY_BUFFER_ALLOC_C */ +#if defined(MBEDTLS_PLATFORM_FAULT_CALLBACKS) + if( strcmp( "MBEDTLS_PLATFORM_FAULT_CALLBACKS", config ) == 0 ) + { + MACRO_EXPANSION_TO_STR( MBEDTLS_PLATFORM_FAULT_CALLBACKS ); + return( 0 ); + } +#endif /* MBEDTLS_PLATFORM_FAULT_CALLBACKS */ + #if defined(MBEDTLS_NET_C) if( strcmp( "MBEDTLS_NET_C", config ) == 0 ) { diff --git a/scripts/config.pl b/scripts/config.pl index fce736662..af85824f1 100755 --- a/scripts/config.pl +++ b/scripts/config.pl @@ -148,6 +148,7 @@ MBEDTLS_SSL_TRANSFORM_OPTIMIZE_CIPHERS MBEDTLS_VALIDATE_SSL_KEYS_INTEGRITY MBEDTLS_OPTIMIZE_TINYCRYPT_ASM MBEDTLS_AES_128_BIT_MASKED +MBEDTLS_PLATFORM_FAULT_CALLBACKS _ALT\s*$ );