diff options
author | Rémi Verschelde <remi@verschelde.fr> | 2023-04-26 17:57:45 +0200 |
---|---|---|
committer | GitHub <noreply@github.com> | 2023-04-26 17:57:45 +0200 |
commit | ba004ea1c3b00c5516548edde7bdfe2d72d51ea1 (patch) | |
tree | 534f23706b47017760b8d5e9395b00ef3ebd385a /thirdparty/mbedtls/library/constant_time.c | |
parent | d78691d44fe6e4f38dce3a89164cdae688772031 (diff) | |
parent | e7f4af091331ef10dd2088d82bc552a097d3d4ce (diff) |
Merge pull request #76476 from YuriSizov/4.0-cherrypicks
Cherry-picks for the 4.0 branch (future 4.0.3) - 3rd batch
Diffstat (limited to 'thirdparty/mbedtls/library/constant_time.c')
-rw-r--r-- | thirdparty/mbedtls/library/constant_time.c | 447 |
1 files changed, 222 insertions, 225 deletions
diff --git a/thirdparty/mbedtls/library/constant_time.c b/thirdparty/mbedtls/library/constant_time.c index 2401b0434a..527930129b 100644 --- a/thirdparty/mbedtls/library/constant_time.c +++ b/thirdparty/mbedtls/library/constant_time.c @@ -17,7 +17,7 @@ * limitations under the License. */ - /* +/* * The following functions are implemented without using comparison operators, as those * might be translated to branches by some compilers on some platforms. */ @@ -46,17 +46,16 @@ #include <string.h> -int mbedtls_ct_memcmp( const void *a, - const void *b, - size_t n ) +int mbedtls_ct_memcmp(const void *a, + const void *b, + size_t n) { size_t i; volatile const unsigned char *A = (volatile const unsigned char *) a; volatile const unsigned char *B = (volatile const unsigned char *) b; volatile unsigned char diff = 0; - for( i = 0; i < n; i++ ) - { + for (i = 0; i < n; i++) { /* Read volatile data in order before computing diff. * This avoids IAR compiler warning: * 'the order of volatile accesses is undefined ..' */ @@ -64,10 +63,10 @@ int mbedtls_ct_memcmp( const void *a, diff |= x ^ y; } - return( (int)diff ); + return (int) diff; } -unsigned mbedtls_ct_uint_mask( unsigned value ) +unsigned mbedtls_ct_uint_mask(unsigned value) { /* MSVC has a warning about unary minus on unsigned, but this is * well-defined and precisely what we want to do here */ @@ -75,7 +74,7 @@ unsigned mbedtls_ct_uint_mask( unsigned value ) #pragma warning( push ) #pragma warning( disable : 4146 ) #endif - return( - ( ( value | - value ) >> ( sizeof( value ) * 8 - 1 ) ) ); + return -((value | -value) >> (sizeof(value) * 8 - 1)); #if defined(_MSC_VER) #pragma warning( pop ) #endif @@ -83,7 +82,7 @@ unsigned mbedtls_ct_uint_mask( unsigned value ) #if defined(MBEDTLS_SSL_SOME_MODES_USE_MAC) -size_t mbedtls_ct_size_mask( size_t value ) +size_t mbedtls_ct_size_mask(size_t value) { /* MSVC has a warning about unary minus on unsigned integer types, * but this is well-defined and precisely what we want to do here. */ @@ -91,7 +90,7 @@ size_t mbedtls_ct_size_mask( size_t value ) #pragma warning( push ) #pragma warning( disable : 4146 ) #endif - return( - ( ( value | - value ) >> ( sizeof( value ) * 8 - 1 ) ) ); + return -((value | -value) >> (sizeof(value) * 8 - 1)); #if defined(_MSC_VER) #pragma warning( pop ) #endif @@ -101,7 +100,7 @@ size_t mbedtls_ct_size_mask( size_t value ) #if defined(MBEDTLS_BIGNUM_C) -mbedtls_mpi_uint mbedtls_ct_mpi_uint_mask( mbedtls_mpi_uint value ) +mbedtls_mpi_uint mbedtls_ct_mpi_uint_mask(mbedtls_mpi_uint value) { /* MSVC has a warning about unary minus on unsigned, but this is * well-defined and precisely what we want to do here */ @@ -109,7 +108,7 @@ mbedtls_mpi_uint mbedtls_ct_mpi_uint_mask( mbedtls_mpi_uint value ) #pragma warning( push ) #pragma warning( disable : 4146 ) #endif - return( - ( ( value | - value ) >> ( sizeof( value ) * 8 - 1 ) ) ); + return -((value | -value) >> (sizeof(value) * 8 - 1)); #if defined(_MSC_VER) #pragma warning( pop ) #endif @@ -131,25 +130,25 @@ mbedtls_mpi_uint mbedtls_ct_mpi_uint_mask( mbedtls_mpi_uint value ) * * \return All-bits-one if \p x is less than \p y, otherwise zero. */ -static size_t mbedtls_ct_size_mask_lt( size_t x, - size_t y ) +static size_t mbedtls_ct_size_mask_lt(size_t x, + size_t y) { /* This has the most significant bit set if and only if x < y */ const size_t sub = x - y; /* sub1 = (x < y) ? 1 : 0 */ - const size_t sub1 = sub >> ( sizeof( sub ) * 8 - 1 ); + const size_t sub1 = sub >> (sizeof(sub) * 8 - 1); /* mask = (x < y) ? 0xff... : 0x00... */ - const size_t mask = mbedtls_ct_size_mask( sub1 ); + const size_t mask = mbedtls_ct_size_mask(sub1); - return( mask ); + return mask; } -size_t mbedtls_ct_size_mask_ge( size_t x, - size_t y ) +size_t mbedtls_ct_size_mask_ge(size_t x, + size_t y) { - return( ~mbedtls_ct_size_mask_lt( x, y ) ); + return ~mbedtls_ct_size_mask_lt(x, y); } #endif /* MBEDTLS_SSL_SOME_SUITES_USE_TLS_CBC */ @@ -161,21 +160,21 @@ size_t mbedtls_ct_size_mask_ge( size_t x, * Constant flow with respect to c. */ MBEDTLS_STATIC_TESTABLE -unsigned char mbedtls_ct_uchar_mask_of_range( unsigned char low, - unsigned char high, - unsigned char c ) +unsigned char mbedtls_ct_uchar_mask_of_range(unsigned char low, + unsigned char high, + unsigned char c) { /* low_mask is: 0 if low <= c, 0x...ff if low > c */ - unsigned low_mask = ( (unsigned) c - low ) >> 8; + unsigned low_mask = ((unsigned) c - low) >> 8; /* high_mask is: 0 if c <= high, 0x...ff if c > high */ - unsigned high_mask = ( (unsigned) high - c ) >> 8; - return( ~( low_mask | high_mask ) & 0xff ); + unsigned high_mask = ((unsigned) high - c) >> 8; + return ~(low_mask | high_mask) & 0xff; } #endif /* MBEDTLS_BASE64_C */ -unsigned mbedtls_ct_size_bool_eq( size_t x, - size_t y ) +unsigned mbedtls_ct_size_bool_eq(size_t x, + size_t y) { /* diff = 0 if x == y, non-zero otherwise */ const size_t diff = x ^ y; @@ -188,16 +187,16 @@ unsigned mbedtls_ct_size_bool_eq( size_t x, #endif /* diff_msb's most significant bit is equal to x != y */ - const size_t diff_msb = ( diff | (size_t) -diff ); + const size_t diff_msb = (diff | (size_t) -diff); #if defined(_MSC_VER) #pragma warning( pop ) #endif /* diff1 = (x != y) ? 1 : 0 */ - const unsigned diff1 = diff_msb >> ( sizeof( diff_msb ) * 8 - 1 ); + const unsigned diff1 = diff_msb >> (sizeof(diff_msb) * 8 - 1); - return( 1 ^ diff1 ); + return 1 ^ diff1; } #if defined(MBEDTLS_PKCS1_V15) && defined(MBEDTLS_RSA_C) && !defined(MBEDTLS_RSA_ALT) @@ -213,19 +212,19 @@ unsigned mbedtls_ct_size_bool_eq( size_t x, * * \return 1 if \p x greater than \p y, otherwise 0. */ -static unsigned mbedtls_ct_size_gt( size_t x, - size_t y ) +static unsigned mbedtls_ct_size_gt(size_t x, + size_t y) { /* Return the sign bit (1 for negative) of (y - x). */ - return( ( y - x ) >> ( sizeof( size_t ) * 8 - 1 ) ); + return (y - x) >> (sizeof(size_t) * 8 - 1); } #endif /* MBEDTLS_PKCS1_V15 && MBEDTLS_RSA_C && ! MBEDTLS_RSA_ALT */ #if defined(MBEDTLS_BIGNUM_C) -unsigned mbedtls_ct_mpi_uint_lt( const mbedtls_mpi_uint x, - const mbedtls_mpi_uint y ) +unsigned mbedtls_ct_mpi_uint_lt(const mbedtls_mpi_uint x, + const mbedtls_mpi_uint y) { mbedtls_mpi_uint ret; mbedtls_mpi_uint cond; @@ -233,12 +232,12 @@ unsigned mbedtls_ct_mpi_uint_lt( const mbedtls_mpi_uint x, /* * Check if the most significant bits (MSB) of the operands are different. */ - cond = ( x ^ y ); + cond = (x ^ y); /* * If the MSB are the same then the difference x-y will be negative (and * have its MSB set to 1 during conversion to unsigned) if and only if x<y. */ - ret = ( x - y ) & ~cond; + ret = (x - y) & ~cond; /* * If the MSB are different, then the operand with the MSB of 1 is the * bigger. (That is if y has MSB of 1, then x<y is true and it is false if @@ -247,19 +246,19 @@ unsigned mbedtls_ct_mpi_uint_lt( const mbedtls_mpi_uint x, ret |= y & cond; - ret = ret >> ( sizeof( mbedtls_mpi_uint ) * 8 - 1 ); + ret = ret >> (sizeof(mbedtls_mpi_uint) * 8 - 1); return (unsigned) ret; } #endif /* MBEDTLS_BIGNUM_C */ -unsigned mbedtls_ct_uint_if( unsigned condition, - unsigned if1, - unsigned if0 ) +unsigned mbedtls_ct_uint_if(unsigned condition, + unsigned if1, + unsigned if0) { - unsigned mask = mbedtls_ct_uint_mask( condition ); - return( ( mask & if1 ) | (~mask & if0 ) ); + unsigned mask = mbedtls_ct_uint_mask(condition); + return (mask & if1) | (~mask & if0); } #if defined(MBEDTLS_BIGNUM_C) @@ -278,9 +277,9 @@ unsigned mbedtls_ct_uint_if( unsigned condition, * * \return \c if1 if \p condition is nonzero, otherwise \c if0. * */ -static int mbedtls_ct_cond_select_sign( unsigned char condition, - int if1, - int if0 ) +static int mbedtls_ct_cond_select_sign(unsigned char condition, + int if1, + int if0) { /* In order to avoid questions about what we can reasonably assume about * the representations of signed integers, move everything to unsigned @@ -292,16 +291,16 @@ static int mbedtls_ct_cond_select_sign( unsigned char condition, const unsigned mask = condition << 1; /* select uif1 or uif0 */ - unsigned ur = ( uif0 & ~mask ) | ( uif1 & mask ); + unsigned ur = (uif0 & ~mask) | (uif1 & mask); /* ur is now 0 or 2, convert back to -1 or +1 */ - return( (int) ur - 1 ); + return (int) ur - 1; } -void mbedtls_ct_mpi_uint_cond_assign( size_t n, - mbedtls_mpi_uint *dest, - const mbedtls_mpi_uint *src, - unsigned char condition ) +void mbedtls_ct_mpi_uint_cond_assign(size_t n, + mbedtls_mpi_uint *dest, + const mbedtls_mpi_uint *src, + unsigned char condition) { size_t i; @@ -319,43 +318,44 @@ void mbedtls_ct_mpi_uint_cond_assign( size_t n, #pragma warning( pop ) #endif - for( i = 0; i < n; i++ ) - dest[i] = ( src[i] & mask ) | ( dest[i] & ~mask ); + for (i = 0; i < n; i++) { + dest[i] = (src[i] & mask) | (dest[i] & ~mask); + } } #endif /* MBEDTLS_BIGNUM_C */ #if defined(MBEDTLS_BASE64_C) -unsigned char mbedtls_ct_base64_enc_char( unsigned char value ) +unsigned char mbedtls_ct_base64_enc_char(unsigned char value) { unsigned char digit = 0; /* For each range of values, if value is in that range, mask digit with * the corresponding value. Since value can only be in a single range, * only at most one masking will change digit. */ - digit |= mbedtls_ct_uchar_mask_of_range( 0, 25, value ) & ( 'A' + value ); - digit |= mbedtls_ct_uchar_mask_of_range( 26, 51, value ) & ( 'a' + value - 26 ); - digit |= mbedtls_ct_uchar_mask_of_range( 52, 61, value ) & ( '0' + value - 52 ); - digit |= mbedtls_ct_uchar_mask_of_range( 62, 62, value ) & '+'; - digit |= mbedtls_ct_uchar_mask_of_range( 63, 63, value ) & '/'; - return( digit ); + digit |= mbedtls_ct_uchar_mask_of_range(0, 25, value) & ('A' + value); + digit |= mbedtls_ct_uchar_mask_of_range(26, 51, value) & ('a' + value - 26); + digit |= mbedtls_ct_uchar_mask_of_range(52, 61, value) & ('0' + value - 52); + digit |= mbedtls_ct_uchar_mask_of_range(62, 62, value) & '+'; + digit |= mbedtls_ct_uchar_mask_of_range(63, 63, value) & '/'; + return digit; } -signed char mbedtls_ct_base64_dec_value( unsigned char c ) +signed char mbedtls_ct_base64_dec_value(unsigned char c) { unsigned char val = 0; /* For each range of digits, if c is in that range, mask val with * the corresponding value. Since c can only be in a single range, * only at most one masking will change val. Set val to one plus * the desired value so that it stays 0 if c is in none of the ranges. */ - val |= mbedtls_ct_uchar_mask_of_range( 'A', 'Z', c ) & ( c - 'A' + 0 + 1 ); - val |= mbedtls_ct_uchar_mask_of_range( 'a', 'z', c ) & ( c - 'a' + 26 + 1 ); - val |= mbedtls_ct_uchar_mask_of_range( '0', '9', c ) & ( c - '0' + 52 + 1 ); - val |= mbedtls_ct_uchar_mask_of_range( '+', '+', c ) & ( c - '+' + 62 + 1 ); - val |= mbedtls_ct_uchar_mask_of_range( '/', '/', c ) & ( c - '/' + 63 + 1 ); + val |= mbedtls_ct_uchar_mask_of_range('A', 'Z', c) & (c - 'A' + 0 + 1); + val |= mbedtls_ct_uchar_mask_of_range('a', 'z', c) & (c - 'a' + 26 + 1); + val |= mbedtls_ct_uchar_mask_of_range('0', '9', c) & (c - '0' + 52 + 1); + val |= mbedtls_ct_uchar_mask_of_range('+', '+', c) & (c - '+' + 62 + 1); + val |= mbedtls_ct_uchar_mask_of_range('/', '/', c) & (c - '/' + 63 + 1); /* At this point, val is 0 if c is an invalid digit and v+1 if c is * a digit with the value v. */ - return( val - 1 ); + return val - 1; } #endif /* MBEDTLS_BASE64_C */ @@ -378,72 +378,71 @@ signed char mbedtls_ct_base64_dec_value( unsigned char c ) * \param total Total size of the buffer. * \param offset Offset from which to copy \p total - \p offset bytes. */ -static void mbedtls_ct_mem_move_to_left( void *start, - size_t total, - size_t offset ) +static void mbedtls_ct_mem_move_to_left(void *start, + size_t total, + size_t offset) { volatile unsigned char *buf = start; size_t i, n; - if( total == 0 ) + if (total == 0) { return; - for( i = 0; i < total; i++ ) - { - unsigned no_op = mbedtls_ct_size_gt( total - offset, i ); + } + for (i = 0; i < total; i++) { + unsigned no_op = mbedtls_ct_size_gt(total - offset, i); /* The first `total - offset` passes are a no-op. The last * `offset` passes shift the data one byte to the left and * zero out the last byte. */ - for( n = 0; n < total - 1; n++ ) - { + for (n = 0; n < total - 1; n++) { unsigned char current = buf[n]; unsigned char next = buf[n+1]; - buf[n] = mbedtls_ct_uint_if( no_op, current, next ); + buf[n] = mbedtls_ct_uint_if(no_op, current, next); } - buf[total-1] = mbedtls_ct_uint_if( no_op, buf[total-1], 0 ); + buf[total-1] = mbedtls_ct_uint_if(no_op, buf[total-1], 0); } } #endif /* MBEDTLS_PKCS1_V15 && MBEDTLS_RSA_C && ! MBEDTLS_RSA_ALT */ #if defined(MBEDTLS_SSL_SOME_MODES_USE_MAC) -void mbedtls_ct_memcpy_if_eq( unsigned char *dest, - const unsigned char *src, - size_t len, - size_t c1, - size_t c2 ) +void mbedtls_ct_memcpy_if_eq(unsigned char *dest, + const unsigned char *src, + size_t len, + size_t c1, + size_t c2) { /* mask = c1 == c2 ? 0xff : 0x00 */ - const size_t equal = mbedtls_ct_size_bool_eq( c1, c2 ); - const unsigned char mask = (unsigned char) mbedtls_ct_size_mask( equal ); + const size_t equal = mbedtls_ct_size_bool_eq(c1, c2); + const unsigned char mask = (unsigned char) mbedtls_ct_size_mask(equal); /* dest[i] = c1 == c2 ? src[i] : dest[i] */ - for( size_t i = 0; i < len; i++ ) - dest[i] = ( src[i] & mask ) | ( dest[i] & ~mask ); + for (size_t i = 0; i < len; i++) { + dest[i] = (src[i] & mask) | (dest[i] & ~mask); + } } -void mbedtls_ct_memcpy_offset( unsigned char *dest, - const unsigned char *src, - size_t offset, - size_t offset_min, - size_t offset_max, - size_t len ) +void mbedtls_ct_memcpy_offset(unsigned char *dest, + const unsigned char *src, + size_t offset, + size_t offset_min, + size_t offset_max, + size_t len) { size_t offsetval; - for( offsetval = offset_min; offsetval <= offset_max; offsetval++ ) - { - mbedtls_ct_memcpy_if_eq( dest, src + offsetval, len, - offsetval, offset ); + for (offsetval = offset_min; offsetval <= offset_max; offsetval++) { + mbedtls_ct_memcpy_if_eq(dest, src + offsetval, len, + offsetval, offset); } } -int mbedtls_ct_hmac( mbedtls_md_context_t *ctx, - const unsigned char *add_data, - size_t add_data_len, - const unsigned char *data, - size_t data_len_secret, - size_t min_data_len, - size_t max_data_len, - unsigned char *output ) +int mbedtls_ct_hmac(mbedtls_md_context_t *ctx, + const unsigned char *add_data, + size_t add_data_len, + const unsigned char *data, + size_t data_len_secret, + size_t min_data_len, + size_t max_data_len, + unsigned char *output) { /* * This function breaks the HMAC abstraction and uses the md_clone() @@ -459,79 +458,79 @@ int mbedtls_ct_hmac( mbedtls_md_context_t *ctx, * * Then we only need to compute HASH(okey + inner_hash) and we're done. */ - const mbedtls_md_type_t md_alg = mbedtls_md_get_type( ctx->md_info ); + const mbedtls_md_type_t md_alg = mbedtls_md_get_type(ctx->md_info); /* TLS 1.0-1.2 only support SHA-384, SHA-256, SHA-1, MD-5, * all of which have the same block size except SHA-384. */ const size_t block_size = md_alg == MBEDTLS_MD_SHA384 ? 128 : 64; const unsigned char * const ikey = ctx->hmac_ctx; const unsigned char * const okey = ikey + block_size; - const size_t hash_size = mbedtls_md_get_size( ctx->md_info ); + const size_t hash_size = mbedtls_md_get_size(ctx->md_info); unsigned char aux_out[MBEDTLS_MD_MAX_SIZE]; mbedtls_md_context_t aux; size_t offset; int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; - mbedtls_md_init( &aux ); + mbedtls_md_init(&aux); -#define MD_CHK( func_call ) \ +#define MD_CHK(func_call) \ do { \ ret = (func_call); \ - if( ret != 0 ) \ - goto cleanup; \ - } while( 0 ) + if (ret != 0) \ + goto cleanup; \ + } while (0) - MD_CHK( mbedtls_md_setup( &aux, ctx->md_info, 0 ) ); + MD_CHK(mbedtls_md_setup(&aux, ctx->md_info, 0)); /* After hmac_start() of hmac_reset(), ikey has already been hashed, * so we can start directly with the message */ - MD_CHK( mbedtls_md_update( ctx, add_data, add_data_len ) ); - MD_CHK( mbedtls_md_update( ctx, data, min_data_len ) ); + MD_CHK(mbedtls_md_update(ctx, add_data, add_data_len)); + MD_CHK(mbedtls_md_update(ctx, data, min_data_len)); /* Fill the hash buffer in advance with something that is * not a valid hash (barring an attack on the hash and * deliberately-crafted input), in case the caller doesn't * check the return status properly. */ - memset( output, '!', hash_size ); + memset(output, '!', hash_size); /* For each possible length, compute the hash up to that point */ - for( offset = min_data_len; offset <= max_data_len; offset++ ) - { - MD_CHK( mbedtls_md_clone( &aux, ctx ) ); - MD_CHK( mbedtls_md_finish( &aux, aux_out ) ); + for (offset = min_data_len; offset <= max_data_len; offset++) { + MD_CHK(mbedtls_md_clone(&aux, ctx)); + MD_CHK(mbedtls_md_finish(&aux, aux_out)); /* Keep only the correct inner_hash in the output buffer */ - mbedtls_ct_memcpy_if_eq( output, aux_out, hash_size, - offset, data_len_secret ); + mbedtls_ct_memcpy_if_eq(output, aux_out, hash_size, + offset, data_len_secret); - if( offset < max_data_len ) - MD_CHK( mbedtls_md_update( ctx, data + offset, 1 ) ); + if (offset < max_data_len) { + MD_CHK(mbedtls_md_update(ctx, data + offset, 1)); + } } /* The context needs to finish() before it starts() again */ - MD_CHK( mbedtls_md_finish( ctx, aux_out ) ); + MD_CHK(mbedtls_md_finish(ctx, aux_out)); /* Now compute HASH(okey + inner_hash) */ - MD_CHK( mbedtls_md_starts( ctx ) ); - MD_CHK( mbedtls_md_update( ctx, okey, block_size ) ); - MD_CHK( mbedtls_md_update( ctx, output, hash_size ) ); - MD_CHK( mbedtls_md_finish( ctx, output ) ); + MD_CHK(mbedtls_md_starts(ctx)); + MD_CHK(mbedtls_md_update(ctx, okey, block_size)); + MD_CHK(mbedtls_md_update(ctx, output, hash_size)); + MD_CHK(mbedtls_md_finish(ctx, output)); /* Done, get ready for next time */ - MD_CHK( mbedtls_md_hmac_reset( ctx ) ); + MD_CHK(mbedtls_md_hmac_reset(ctx)); #undef MD_CHK cleanup: - mbedtls_md_free( &aux ); - return( ret ); + mbedtls_md_free(&aux); + return ret; } #endif /* MBEDTLS_SSL_SOME_MODES_USE_MAC */ #if defined(MBEDTLS_BIGNUM_C) -#define MPI_VALIDATE_RET( cond ) \ - MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_MPI_BAD_INPUT_DATA ) +#define MPI_VALIDATE_RET(cond) \ + MBEDTLS_INTERNAL_VALIDATE_RET(cond, MBEDTLS_ERR_MPI_BAD_INPUT_DATA) /* * Conditionally assign X = Y, without leaking information @@ -545,30 +544,31 @@ cleanup: */ __declspec(noinline) #endif -int mbedtls_mpi_safe_cond_assign( mbedtls_mpi *X, - const mbedtls_mpi *Y, - unsigned char assign ) +int mbedtls_mpi_safe_cond_assign(mbedtls_mpi *X, + const mbedtls_mpi *Y, + unsigned char assign) { int ret = 0; size_t i; mbedtls_mpi_uint limb_mask; - MPI_VALIDATE_RET( X != NULL ); - MPI_VALIDATE_RET( Y != NULL ); + MPI_VALIDATE_RET(X != NULL); + MPI_VALIDATE_RET(Y != NULL); /* all-bits 1 if assign is 1, all-bits 0 if assign is 0 */ - limb_mask = mbedtls_ct_mpi_uint_mask( assign );; + limb_mask = mbedtls_ct_mpi_uint_mask(assign);; - MBEDTLS_MPI_CHK( mbedtls_mpi_grow( X, Y->n ) ); + MBEDTLS_MPI_CHK(mbedtls_mpi_grow(X, Y->n)); - X->s = mbedtls_ct_cond_select_sign( assign, Y->s, X->s ); + X->s = mbedtls_ct_cond_select_sign(assign, Y->s, X->s); - mbedtls_ct_mpi_uint_cond_assign( Y->n, X->p, Y->p, assign ); + mbedtls_ct_mpi_uint_cond_assign(Y->n, X->p, Y->p, assign); - for( i = Y->n; i < X->n; i++ ) + for (i = Y->n; i < X->n; i++) { X->p[i] &= ~limb_mask; + } cleanup: - return( ret ); + return ret; } /* @@ -577,73 +577,74 @@ cleanup: * Here it is not ok to simply swap the pointers, which would lead to * different memory access patterns when X and Y are used afterwards. */ -int mbedtls_mpi_safe_cond_swap( mbedtls_mpi *X, - mbedtls_mpi *Y, - unsigned char swap ) +int mbedtls_mpi_safe_cond_swap(mbedtls_mpi *X, + mbedtls_mpi *Y, + unsigned char swap) { int ret, s; size_t i; mbedtls_mpi_uint limb_mask; mbedtls_mpi_uint tmp; - MPI_VALIDATE_RET( X != NULL ); - MPI_VALIDATE_RET( Y != NULL ); + MPI_VALIDATE_RET(X != NULL); + MPI_VALIDATE_RET(Y != NULL); - if( X == Y ) - return( 0 ); + if (X == Y) { + return 0; + } /* all-bits 1 if swap is 1, all-bits 0 if swap is 0 */ - limb_mask = mbedtls_ct_mpi_uint_mask( swap ); + limb_mask = mbedtls_ct_mpi_uint_mask(swap); - MBEDTLS_MPI_CHK( mbedtls_mpi_grow( X, Y->n ) ); - MBEDTLS_MPI_CHK( mbedtls_mpi_grow( Y, X->n ) ); + MBEDTLS_MPI_CHK(mbedtls_mpi_grow(X, Y->n)); + MBEDTLS_MPI_CHK(mbedtls_mpi_grow(Y, X->n)); s = X->s; - X->s = mbedtls_ct_cond_select_sign( swap, Y->s, X->s ); - Y->s = mbedtls_ct_cond_select_sign( swap, s, Y->s ); + X->s = mbedtls_ct_cond_select_sign(swap, Y->s, X->s); + Y->s = mbedtls_ct_cond_select_sign(swap, s, Y->s); - for( i = 0; i < X->n; i++ ) - { + for (i = 0; i < X->n; i++) { tmp = X->p[i]; - X->p[i] = ( X->p[i] & ~limb_mask ) | ( Y->p[i] & limb_mask ); - Y->p[i] = ( Y->p[i] & ~limb_mask ) | ( tmp & limb_mask ); + X->p[i] = (X->p[i] & ~limb_mask) | (Y->p[i] & limb_mask); + Y->p[i] = (Y->p[i] & ~limb_mask) | (tmp & limb_mask); } cleanup: - return( ret ); + return ret; } /* * Compare signed values in constant time */ -int mbedtls_mpi_lt_mpi_ct( const mbedtls_mpi *X, - const mbedtls_mpi *Y, - unsigned *ret ) +int mbedtls_mpi_lt_mpi_ct(const mbedtls_mpi *X, + const mbedtls_mpi *Y, + unsigned *ret) { size_t i; /* The value of any of these variables is either 0 or 1 at all times. */ unsigned cond, done, X_is_negative, Y_is_negative; - MPI_VALIDATE_RET( X != NULL ); - MPI_VALIDATE_RET( Y != NULL ); - MPI_VALIDATE_RET( ret != NULL ); + MPI_VALIDATE_RET(X != NULL); + MPI_VALIDATE_RET(Y != NULL); + MPI_VALIDATE_RET(ret != NULL); - if( X->n != Y->n ) + if (X->n != Y->n) { return MBEDTLS_ERR_MPI_BAD_INPUT_DATA; + } /* * Set sign_N to 1 if N >= 0, 0 if N < 0. * We know that N->s == 1 if N >= 0 and N->s == -1 if N < 0. */ - X_is_negative = ( X->s & 2 ) >> 1; - Y_is_negative = ( Y->s & 2 ) >> 1; + X_is_negative = (X->s & 2) >> 1; + Y_is_negative = (Y->s & 2) >> 1; /* * If the signs are different, then the positive operand is the bigger. * That is if X is negative (X_is_negative == 1), then X < Y is true and it * is false if X is positive (X_is_negative == 0). */ - cond = ( X_is_negative ^ Y_is_negative ); + cond = (X_is_negative ^ Y_is_negative); *ret = cond & X_is_negative; /* @@ -652,8 +653,7 @@ int mbedtls_mpi_lt_mpi_ct( const mbedtls_mpi *X, */ done = cond; - for( i = X->n; i > 0; i-- ) - { + for (i = X->n; i > 0; i--) { /* * If Y->p[i - 1] < X->p[i - 1] then X < Y is true if and only if both * X and Y are negative. @@ -661,8 +661,8 @@ int mbedtls_mpi_lt_mpi_ct( const mbedtls_mpi *X, * Again even if we can make a decision, we just mark the result and * the fact that we are done and continue looping. */ - cond = mbedtls_ct_mpi_uint_lt( Y->p[i - 1], X->p[i - 1] ); - *ret |= cond & ( 1 - done ) & X_is_negative; + cond = mbedtls_ct_mpi_uint_lt(Y->p[i - 1], X->p[i - 1]); + *ret |= cond & (1 - done) & X_is_negative; done |= cond; /* @@ -672,24 +672,24 @@ int mbedtls_mpi_lt_mpi_ct( const mbedtls_mpi *X, * Again even if we can make a decision, we just mark the result and * the fact that we are done and continue looping. */ - cond = mbedtls_ct_mpi_uint_lt( X->p[i - 1], Y->p[i - 1] ); - *ret |= cond & ( 1 - done ) & ( 1 - X_is_negative ); + cond = mbedtls_ct_mpi_uint_lt(X->p[i - 1], Y->p[i - 1]); + *ret |= cond & (1 - done) & (1 - X_is_negative); done |= cond; } - return( 0 ); + return 0; } #endif /* MBEDTLS_BIGNUM_C */ #if defined(MBEDTLS_PKCS1_V15) && defined(MBEDTLS_RSA_C) && !defined(MBEDTLS_RSA_ALT) -int mbedtls_ct_rsaes_pkcs1_v15_unpadding( int mode, - unsigned char *input, - size_t ilen, - unsigned char *output, - size_t output_max_len, - size_t *olen ) +int mbedtls_ct_rsaes_pkcs1_v15_unpadding(int mode, + unsigned char *input, + size_t ilen, + unsigned char *output, + size_t output_max_len, + size_t *olen) { int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; size_t i, plaintext_max_size; @@ -710,29 +710,25 @@ int mbedtls_ct_rsaes_pkcs1_v15_unpadding( int mode, size_t plaintext_size = 0; unsigned output_too_large; - plaintext_max_size = ( output_max_len > ilen - 11 ) ? ilen - 11 + plaintext_max_size = (output_max_len > ilen - 11) ? ilen - 11 : output_max_len; /* Check and get padding length in constant time and constant * memory trace. The first byte must be 0. */ bad |= input[0]; - if( mode == MBEDTLS_RSA_PRIVATE ) - { + if (mode == MBEDTLS_RSA_PRIVATE) { /* Decode EME-PKCS1-v1_5 padding: 0x00 || 0x02 || PS || 0x00 * where PS must be at least 8 nonzero bytes. */ bad |= input[1] ^ MBEDTLS_RSA_CRYPT; /* Read the whole buffer. Set pad_done to nonzero if we find * the 0x00 byte and remember the padding length in pad_count. */ - for( i = 2; i < ilen; i++ ) - { - pad_done |= ((input[i] | (unsigned char)-input[i]) >> 7) ^ 1; - pad_count += ((pad_done | (unsigned char)-pad_done) >> 7) ^ 1; + for (i = 2; i < ilen; i++) { + pad_done |= ((input[i] | (unsigned char) -input[i]) >> 7) ^ 1; + pad_count += ((pad_done | (unsigned char) -pad_done) >> 7) ^ 1; } - } - else - { + } else { /* Decode EMSA-PKCS1-v1_5 padding: 0x00 || 0x01 || PS || 0x00 * where PS must be at least 8 bytes with the value 0xFF. */ bad |= input[1] ^ MBEDTLS_RSA_SIGN; @@ -740,19 +736,18 @@ int mbedtls_ct_rsaes_pkcs1_v15_unpadding( int mode, /* Read the whole buffer. Set pad_done to nonzero if we find * the 0x00 byte and remember the padding length in pad_count. * If there's a non-0xff byte in the padding, the padding is bad. */ - for( i = 2; i < ilen; i++ ) - { - pad_done |= mbedtls_ct_uint_if( input[i], 0, 1 ); - pad_count += mbedtls_ct_uint_if( pad_done, 0, 1 ); - bad |= mbedtls_ct_uint_if( pad_done, 0, input[i] ^ 0xFF ); + for (i = 2; i < ilen; i++) { + pad_done |= mbedtls_ct_uint_if(input[i], 0, 1); + pad_count += mbedtls_ct_uint_if(pad_done, 0, 1); + bad |= mbedtls_ct_uint_if(pad_done, 0, input[i] ^ 0xFF); } } /* If pad_done is still zero, there's no data, only unfinished padding. */ - bad |= mbedtls_ct_uint_if( pad_done, 0, 1 ); + bad |= mbedtls_ct_uint_if(pad_done, 0, 1); /* There must be at least 8 bytes of padding. */ - bad |= mbedtls_ct_size_gt( 8, pad_count ); + bad |= mbedtls_ct_size_gt(8, pad_count); /* If the padding is valid, set plaintext_size to the number of * remaining bytes after stripping the padding. If the padding @@ -762,24 +757,24 @@ int mbedtls_ct_rsaes_pkcs1_v15_unpadding( int mode, * validity through timing. RSA keys are small enough that all the * size_t values involved fit in unsigned int. */ plaintext_size = mbedtls_ct_uint_if( - bad, (unsigned) plaintext_max_size, - (unsigned) ( ilen - pad_count - 3 ) ); + bad, (unsigned) plaintext_max_size, + (unsigned) (ilen - pad_count - 3)); /* Set output_too_large to 0 if the plaintext fits in the output * buffer and to 1 otherwise. */ - output_too_large = mbedtls_ct_size_gt( plaintext_size, - plaintext_max_size ); + output_too_large = mbedtls_ct_size_gt(plaintext_size, + plaintext_max_size); /* Set ret without branches to avoid timing attacks. Return: * - INVALID_PADDING if the padding is bad (bad != 0). * - OUTPUT_TOO_LARGE if the padding is good but the decrypted * plaintext does not fit in the output buffer. * - 0 if the padding is correct. */ - ret = - (int) mbedtls_ct_uint_if( - bad, - MBEDTLS_ERR_RSA_INVALID_PADDING, - mbedtls_ct_uint_if( output_too_large, - - MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE, - 0 ) ); + ret = -(int) mbedtls_ct_uint_if( + bad, -MBEDTLS_ERR_RSA_INVALID_PADDING, + mbedtls_ct_uint_if(output_too_large, + -MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE, + 0)); /* If the padding is bad or the plaintext is too large, zero the * data that we're about to copy to the output buffer. @@ -787,17 +782,18 @@ int mbedtls_ct_rsaes_pkcs1_v15_unpadding( int mode, * from the same buffer whether the padding is good or not to * avoid leaking the padding validity through overall timing or * through memory or cache access patterns. */ - bad = mbedtls_ct_uint_mask( bad | output_too_large ); - for( i = 11; i < ilen; i++ ) + bad = mbedtls_ct_uint_mask(bad | output_too_large); + for (i = 11; i < ilen; i++) { input[i] &= ~bad; + } /* If the plaintext is too large, truncate it to the buffer size. * Copy anyway to avoid revealing the length through timing, because * revealing the length is as bad as revealing the padding validity * for a Bleichenbacher attack. */ - plaintext_size = mbedtls_ct_uint_if( output_too_large, - (unsigned) plaintext_max_size, - (unsigned) plaintext_size ); + plaintext_size = mbedtls_ct_uint_if(output_too_large, + (unsigned) plaintext_max_size, + (unsigned) plaintext_size); /* Move the plaintext to the leftmost position where it can start in * the working buffer, i.e. make it start plaintext_max_size from @@ -805,9 +801,9 @@ int mbedtls_ct_rsaes_pkcs1_v15_unpadding( int mode, * does not depend on the plaintext size. After this move, the * starting location of the plaintext is no longer sensitive * information. */ - mbedtls_ct_mem_move_to_left( input + ilen - plaintext_max_size, - plaintext_max_size, - plaintext_max_size - plaintext_size ); + mbedtls_ct_mem_move_to_left(input + ilen - plaintext_max_size, + plaintext_max_size, + plaintext_max_size - plaintext_size); /* Finally copy the decrypted plaintext plus trailing zeros into the output * buffer. If output_max_len is 0, then output may be an invalid pointer @@ -816,8 +812,9 @@ int mbedtls_ct_rsaes_pkcs1_v15_unpadding( int mode, * user-provided output buffer), which is independent from plaintext * length, validity of padding, success of the decryption, and other * secrets. */ - if( output_max_len != 0 ) - memcpy( output, input + ilen - plaintext_max_size, plaintext_max_size ); + if (output_max_len != 0) { + memcpy(output, input + ilen - plaintext_max_size, plaintext_max_size); + } /* Report the amount of data we copied to the output buffer. In case * of errors (bad padding or output too large), the value of *olen @@ -825,7 +822,7 @@ int mbedtls_ct_rsaes_pkcs1_v15_unpadding( int mode, * to the good case limits the risks of leaking the padding validity. */ *olen = plaintext_size; - return( ret ); + return ret; } #endif /* MBEDTLS_PKCS1_V15 && MBEDTLS_RSA_C && ! MBEDTLS_RSA_ALT */ |