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Rename constant-time functions to have mbedtls_ct prefix

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Rename functions to better suite with the module name.

Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
This commit is contained in:
Gabor Mezei 2021-10-20 11:59:27 +02:00
parent f127a0e2b1
commit 18a44949d0
No known key found for this signature in database
GPG Key ID: 106F5A41ECC305BD
13 changed files with 91 additions and 91 deletions
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2
include/mbedtls/constant_time.h
View File

@ -38,7 +38,7 @@
* \return Zero if the content of the two buffer is the same, * \return Zero if the content of the two buffer is the same,
* otherwise non-zero. * otherwise non-zero.
*/ */
int mbedtls_cf_memcmp( const void *a, int mbedtls_ct_memcmp( const void *a,
const void *b, const void *b,
size_t n ); size_t n );

4
library/bignum.c
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@ -1951,7 +1951,7 @@ static void mpi_montmul( mbedtls_mpi *A, const mbedtls_mpi *B, const mbedtls_mpi
* so d[n] == 1 and we want to set A to the result of the subtraction * so d[n] == 1 and we want to set A to the result of the subtraction
* which is d - (2^biL)^n, i.e. the n least significant limbs of d. * which is d - (2^biL)^n, i.e. the n least significant limbs of d.
* This exactly corresponds to a conditional assignment. */ * This exactly corresponds to a conditional assignment. */
mbedtls_cf_mpi_uint_cond_assign( n, A->p, d, (unsigned char) d[n] ); mbedtls_ct_mpi_uint_cond_assign( n, A->p, d, (unsigned char) d[n] );
} }
/* /*
@ -1993,7 +1993,7 @@ static int mpi_select( mbedtls_mpi *R, const mbedtls_mpi *T, size_t T_size, size
for( size_t i = 0; i < T_size; i++ ) for( size_t i = 0; i < T_size; i++ )
{ {
MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_assign( R, &T[i], MBEDTLS_MPI_CHK( mbedtls_mpi_safe_cond_assign( R, &T[i],
(unsigned char) mbedtls_cf_size_bool_eq( i, idx ) ) ); (unsigned char) mbedtls_ct_size_bool_eq( i, idx ) ) );
} }
cleanup: cleanup:

4
library/cipher.c
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@ -1139,7 +1139,7 @@ int mbedtls_cipher_check_tag( mbedtls_cipher_context_t *ctx,
} }
/* Check the tag in "constant-time" */ /* Check the tag in "constant-time" */
if( mbedtls_cf_memcmp( tag, check_tag, tag_len ) != 0 ) if( mbedtls_ct_memcmp( tag, check_tag, tag_len ) != 0 )
return( MBEDTLS_ERR_CIPHER_AUTH_FAILED ); return( MBEDTLS_ERR_CIPHER_AUTH_FAILED );
return( 0 ); return( 0 );
@ -1161,7 +1161,7 @@ int mbedtls_cipher_check_tag( mbedtls_cipher_context_t *ctx,
} }
/* Check the tag in "constant-time" */ /* Check the tag in "constant-time" */
if( mbedtls_cf_memcmp( tag, check_tag, tag_len ) != 0 ) if( mbedtls_ct_memcmp( tag, check_tag, tag_len ) != 0 )
return( MBEDTLS_ERR_CIPHER_AUTH_FAILED ); return( MBEDTLS_ERR_CIPHER_AUTH_FAILED );
return( 0 ); return( 0 );

96
library/constant_time.c
View File

@ -42,7 +42,7 @@
#include <string.h> #include <string.h>
int mbedtls_cf_memcmp( const void *a, int mbedtls_ct_memcmp( const void *a,
const void *b, const void *b,
size_t n ) size_t n )
{ {
@ -63,7 +63,7 @@ int mbedtls_cf_memcmp( const void *a,
return( (int)diff ); return( (int)diff );
} }
unsigned mbedtls_cf_uint_mask( unsigned value ) unsigned mbedtls_ct_uint_mask( unsigned value )
{ {
/* MSVC has a warning about unary minus on unsigned, but this is /* MSVC has a warning about unary minus on unsigned, but this is
* well-defined and precisely what we want to do here */ * well-defined and precisely what we want to do here */
@ -79,7 +79,7 @@ unsigned mbedtls_cf_uint_mask( unsigned value )
#if defined(MBEDTLS_SSL_SOME_SUITES_USE_TLS_CBC) #if defined(MBEDTLS_SSL_SOME_SUITES_USE_TLS_CBC)
size_t mbedtls_cf_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, /* MSVC has a warning about unary minus on unsigned integer types,
* but this is well-defined and precisely what we want to do here. */ * but this is well-defined and precisely what we want to do here. */
@ -97,7 +97,7 @@ size_t mbedtls_cf_size_mask( size_t value )
#if defined(MBEDTLS_BIGNUM_C) #if defined(MBEDTLS_BIGNUM_C)
mbedtls_mpi_uint mbedtls_cf_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 /* MSVC has a warning about unary minus on unsigned, but this is
* well-defined and precisely what we want to do here */ * well-defined and precisely what we want to do here */
@ -127,7 +127,7 @@ mbedtls_mpi_uint mbedtls_cf_mpi_uint_mask( mbedtls_mpi_uint value )
* *
* \return All-bits-one if \p x is less than \p y, otherwise zero. * \return All-bits-one if \p x is less than \p y, otherwise zero.
*/ */
static size_t mbedtls_cf_size_mask_lt( size_t x, static size_t mbedtls_ct_size_mask_lt( size_t x,
size_t y ) size_t y )
{ {
/* This has the most significant bit set if and only if x < y */ /* This has the most significant bit set if and only if x < y */
@ -137,20 +137,20 @@ static size_t mbedtls_cf_size_mask_lt( size_t x,
const size_t sub1 = sub >> ( sizeof( sub ) * 8 - 1 ); const size_t sub1 = sub >> ( sizeof( sub ) * 8 - 1 );
/* mask = (x < y) ? 0xff... : 0x00... */ /* mask = (x < y) ? 0xff... : 0x00... */
const size_t mask = mbedtls_cf_size_mask( sub1 ); const size_t mask = mbedtls_ct_size_mask( sub1 );
return( mask ); return( mask );
} }
size_t mbedtls_cf_size_mask_ge( size_t x, size_t mbedtls_ct_size_mask_ge( size_t x,
size_t y ) size_t y )
{ {
return( ~mbedtls_cf_size_mask_lt( x, y ) ); return( ~mbedtls_ct_size_mask_lt( x, y ) );
} }
#endif /* MBEDTLS_SSL_SOME_SUITES_USE_TLS_CBC */ #endif /* MBEDTLS_SSL_SOME_SUITES_USE_TLS_CBC */
unsigned mbedtls_cf_size_bool_eq( size_t x, unsigned mbedtls_ct_size_bool_eq( size_t x,
size_t y ) size_t y )
{ {
/* diff = 0 if x == y, non-zero otherwise */ /* diff = 0 if x == y, non-zero otherwise */
@ -189,7 +189,7 @@ unsigned mbedtls_cf_size_bool_eq( size_t x,
* *
* \return 1 if \p x greater than \p y, otherwise 0. * \return 1 if \p x greater than \p y, otherwise 0.
*/ */
static unsigned mbedtls_cf_size_gt( size_t x, static unsigned mbedtls_ct_size_gt( size_t x,
size_t y ) size_t y )
{ {
/* Return the sign bit (1 for negative) of (y - x). */ /* Return the sign bit (1 for negative) of (y - x). */
@ -200,7 +200,7 @@ static unsigned mbedtls_cf_size_gt( size_t x,
#if defined(MBEDTLS_BIGNUM_C) #if defined(MBEDTLS_BIGNUM_C)
unsigned mbedtls_cf_mpi_uint_lt( const mbedtls_mpi_uint x, unsigned mbedtls_ct_mpi_uint_lt( const mbedtls_mpi_uint x,
const mbedtls_mpi_uint y ) const mbedtls_mpi_uint y )
{ {
mbedtls_mpi_uint ret; mbedtls_mpi_uint ret;
@ -230,11 +230,11 @@ unsigned mbedtls_cf_mpi_uint_lt( const mbedtls_mpi_uint x,
#endif /* MBEDTLS_BIGNUM_C */ #endif /* MBEDTLS_BIGNUM_C */
unsigned mbedtls_cf_uint_if( unsigned condition, unsigned mbedtls_ct_uint_if( unsigned condition,
unsigned if1, unsigned if1,
unsigned if0 ) unsigned if0 )
{ {
unsigned mask = mbedtls_cf_uint_mask( condition ); unsigned mask = mbedtls_ct_uint_mask( condition );
return( ( mask & if1 ) | (~mask & if0 ) ); return( ( mask & if1 ) | (~mask & if0 ) );
} }
@ -254,7 +254,7 @@ unsigned mbedtls_cf_uint_if( unsigned condition,
* *
* \return \c if1 if \p condition is nonzero, otherwise \c if0. * \return \c if1 if \p condition is nonzero, otherwise \c if0.
* */ * */
static int mbedtls_cf_cond_select_sign( unsigned char condition, static int mbedtls_ct_cond_select_sign( unsigned char condition,
int if1, int if1,
int if0 ) int if0 )
{ {
@ -274,7 +274,7 @@ static int mbedtls_cf_cond_select_sign( unsigned char condition,
return( (int) ur - 1 ); return( (int) ur - 1 );
} }
void mbedtls_cf_mpi_uint_cond_assign( size_t n, void mbedtls_ct_mpi_uint_cond_assign( size_t n,
mbedtls_mpi_uint *dest, mbedtls_mpi_uint *dest,
const mbedtls_mpi_uint *src, const mbedtls_mpi_uint *src,
unsigned char condition ) unsigned char condition )
@ -305,7 +305,7 @@ void mbedtls_cf_mpi_uint_cond_assign( size_t n,
/** Shift some data towards the left inside a buffer. /** Shift some data towards the left inside a buffer.
* *
* `mbedtls_cf_mem_move_to_left(start, total, offset)` is functionally * `mbedtls_ct_mem_move_to_left(start, total, offset)` is functionally
* equivalent to * equivalent to
* ``` * ```
* memmove(start, start + offset, total - offset); * memmove(start, start + offset, total - offset);
@ -319,7 +319,7 @@ void mbedtls_cf_mpi_uint_cond_assign( size_t n,
* \param total Total size of the buffer. * \param total Total size of the buffer.
* \param offset Offset from which to copy \p total - \p offset bytes. * \param offset Offset from which to copy \p total - \p offset bytes.
*/ */
static void mbedtls_cf_mem_move_to_left( void *start, static void mbedtls_ct_mem_move_to_left( void *start,
size_t total, size_t total,
size_t offset ) size_t offset )
{ {
@ -329,7 +329,7 @@ static void mbedtls_cf_mem_move_to_left( void *start,
return; return;
for( i = 0; i < total; i++ ) for( i = 0; i < total; i++ )
{ {
unsigned no_op = mbedtls_cf_size_gt( total - offset, i ); unsigned no_op = mbedtls_ct_size_gt( total - offset, i );
/* The first `total - offset` passes are a no-op. The last /* The first `total - offset` passes are a no-op. The last
* `offset` passes shift the data one byte to the left and * `offset` passes shift the data one byte to the left and
* zero out the last byte. */ * zero out the last byte. */
@ -337,9 +337,9 @@ static void mbedtls_cf_mem_move_to_left( void *start,
{ {
unsigned char current = buf[n]; unsigned char current = buf[n];
unsigned char next = buf[n+1]; unsigned char next = buf[n+1];
buf[n] = mbedtls_cf_uint_if( no_op, current, next ); buf[n] = mbedtls_ct_uint_if( no_op, current, next );
} }
buf[total-1] = mbedtls_cf_uint_if( no_op, buf[total-1], 0 ); buf[total-1] = mbedtls_ct_uint_if( no_op, buf[total-1], 0 );
} }
} }
@ -347,22 +347,22 @@ static void mbedtls_cf_mem_move_to_left( void *start,
#if defined(MBEDTLS_SSL_SOME_SUITES_USE_TLS_CBC) #if defined(MBEDTLS_SSL_SOME_SUITES_USE_TLS_CBC)
void mbedtls_cf_memcpy_if_eq( unsigned char *dest, void mbedtls_ct_memcpy_if_eq( unsigned char *dest,
const unsigned char *src, const unsigned char *src,
size_t len, size_t len,
size_t c1, size_t c1,
size_t c2 ) size_t c2 )
{ {
/* mask = c1 == c2 ? 0xff : 0x00 */ /* mask = c1 == c2 ? 0xff : 0x00 */
const size_t equal = mbedtls_cf_size_bool_eq( c1, c2 ); const size_t equal = mbedtls_ct_size_bool_eq( c1, c2 );
const unsigned char mask = (unsigned char) mbedtls_cf_size_mask( equal ); const unsigned char mask = (unsigned char) mbedtls_ct_size_mask( equal );
/* dest[i] = c1 == c2 ? src[i] : dest[i] */ /* dest[i] = c1 == c2 ? src[i] : dest[i] */
for( size_t i = 0; i < len; i++ ) for( size_t i = 0; i < len; i++ )
dest[i] = ( src[i] & mask ) | ( dest[i] & ~mask ); dest[i] = ( src[i] & mask ) | ( dest[i] & ~mask );
} }
void mbedtls_cf_memcpy_offset( unsigned char *dest, void mbedtls_ct_memcpy_offset( unsigned char *dest,
const unsigned char *src, const unsigned char *src,
size_t offset, size_t offset,
size_t offset_min, size_t offset_min,
@ -373,12 +373,12 @@ void mbedtls_cf_memcpy_offset( unsigned char *dest,
for( offsetval = offset_min; offsetval <= offset_max; offsetval++ ) for( offsetval = offset_min; offsetval <= offset_max; offsetval++ )
{ {
mbedtls_cf_memcpy_if_eq( dest, src + offsetval, len, mbedtls_ct_memcpy_if_eq( dest, src + offsetval, len,
offsetval, offset ); offsetval, offset );
} }
} }
int mbedtls_cf_hmac( mbedtls_md_context_t *ctx, int mbedtls_ct_hmac( mbedtls_md_context_t *ctx,
const unsigned char *add_data, const unsigned char *add_data,
size_t add_data_len, size_t add_data_len,
const unsigned char *data, const unsigned char *data,
@ -436,7 +436,7 @@ int mbedtls_cf_hmac( mbedtls_md_context_t *ctx,
MD_CHK( mbedtls_md_clone( &aux, ctx ) ); MD_CHK( mbedtls_md_clone( &aux, ctx ) );
MD_CHK( mbedtls_md_finish( &aux, aux_out ) ); MD_CHK( mbedtls_md_finish( &aux, aux_out ) );
/* Keep only the correct inner_hash in the output buffer */ /* Keep only the correct inner_hash in the output buffer */
mbedtls_cf_memcpy_if_eq( output, aux_out, hash_size, mbedtls_ct_memcpy_if_eq( output, aux_out, hash_size,
offset, data_len_secret ); offset, data_len_secret );
if( offset < max_data_len ) if( offset < max_data_len )
@ -485,13 +485,13 @@ int mbedtls_mpi_safe_cond_assign( mbedtls_mpi *X,
MPI_VALIDATE_RET( Y != NULL ); MPI_VALIDATE_RET( Y != NULL );
/* all-bits 1 if assign is 1, all-bits 0 if assign is 0 */ /* all-bits 1 if assign is 1, all-bits 0 if assign is 0 */
limb_mask = mbedtls_cf_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_cf_cond_select_sign( assign, Y->s, X->s ); X->s = mbedtls_ct_cond_select_sign( assign, Y->s, X->s );
mbedtls_cf_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; X->p[i] &= ~limb_mask;
@ -521,14 +521,14 @@ int mbedtls_mpi_safe_cond_swap( mbedtls_mpi *X,
return( 0 ); return( 0 );
/* all-bits 1 if swap is 1, all-bits 0 if swap is 0 */ /* all-bits 1 if swap is 1, all-bits 0 if swap is 0 */
limb_mask = mbedtls_cf_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( X, Y->n ) );
MBEDTLS_MPI_CHK( mbedtls_mpi_grow( Y, X->n ) ); MBEDTLS_MPI_CHK( mbedtls_mpi_grow( Y, X->n ) );
s = X->s; s = X->s;
X->s = mbedtls_cf_cond_select_sign( swap, Y->s, X->s ); X->s = mbedtls_ct_cond_select_sign( swap, Y->s, X->s );
Y->s = mbedtls_cf_cond_select_sign( swap, s, Y->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++ )
@ -590,7 +590,7 @@ int mbedtls_mpi_lt_mpi_ct( const mbedtls_mpi *X,
* Again even if we can make a decision, we just mark the result and * Again even if we can make a decision, we just mark the result and
* the fact that we are done and continue looping. * the fact that we are done and continue looping.
*/ */
cond = mbedtls_cf_mpi_uint_lt( Y->p[i - 1], X->p[i - 1] ); cond = mbedtls_ct_mpi_uint_lt( Y->p[i - 1], X->p[i - 1] );
*ret |= cond & ( 1 - done ) & X_is_negative; *ret |= cond & ( 1 - done ) & X_is_negative;
done |= cond; done |= cond;
@ -601,7 +601,7 @@ int mbedtls_mpi_lt_mpi_ct( const mbedtls_mpi *X,
* Again even if we can make a decision, we just mark the result and * Again even if we can make a decision, we just mark the result and
* the fact that we are done and continue looping. * the fact that we are done and continue looping.
*/ */
cond = mbedtls_cf_mpi_uint_lt( X->p[i - 1], Y->p[i - 1] ); cond = mbedtls_ct_mpi_uint_lt( X->p[i - 1], Y->p[i - 1] );
*ret |= cond & ( 1 - done ) & ( 1 - X_is_negative ); *ret |= cond & ( 1 - done ) & ( 1 - X_is_negative );
done |= cond; done |= cond;
} }
@ -613,7 +613,7 @@ int mbedtls_mpi_lt_mpi_ct( const mbedtls_mpi *X,
#if defined(MBEDTLS_PKCS1_V15) && defined(MBEDTLS_RSA_C) && !defined(MBEDTLS_RSA_ALT) #if defined(MBEDTLS_PKCS1_V15) && defined(MBEDTLS_RSA_C) && !defined(MBEDTLS_RSA_ALT)
int mbedtls_cf_rsaes_pkcs1_v15_unpadding( int mode, int mbedtls_ct_rsaes_pkcs1_v15_unpadding( int mode,
unsigned char *input, unsigned char *input,
size_t ilen, size_t ilen,
unsigned char *output, unsigned char *output,
@ -671,17 +671,17 @@ int mbedtls_cf_rsaes_pkcs1_v15_unpadding( int mode,
* If there's a non-0xff byte in the padding, the padding is bad. */ * If there's a non-0xff byte in the padding, the padding is bad. */
for( i = 2; i < ilen; i++ ) for( i = 2; i < ilen; i++ )
{ {
pad_done |= mbedtls_cf_uint_if( input[i], 0, 1 ); pad_done |= mbedtls_ct_uint_if( input[i], 0, 1 );
pad_count += mbedtls_cf_uint_if( pad_done, 0, 1 ); pad_count += mbedtls_ct_uint_if( pad_done, 0, 1 );
bad |= mbedtls_cf_uint_if( pad_done, 0, input[i] ^ 0xFF ); bad |= mbedtls_ct_uint_if( pad_done, 0, input[i] ^ 0xFF );
} }
} }
/* If pad_done is still zero, there's no data, only unfinished padding. */ /* If pad_done is still zero, there's no data, only unfinished padding. */
bad |= mbedtls_cf_uint_if( pad_done, 0, 1 ); bad |= mbedtls_ct_uint_if( pad_done, 0, 1 );
/* There must be at least 8 bytes of padding. */ /* There must be at least 8 bytes of padding. */
bad |= mbedtls_cf_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 /* If the padding is valid, set plaintext_size to the number of
* remaining bytes after stripping the padding. If the padding * remaining bytes after stripping the padding. If the padding
@ -690,13 +690,13 @@ int mbedtls_cf_rsaes_pkcs1_v15_unpadding( int mode,
* buffer. Do it without branches to avoid leaking the padding * buffer. Do it without branches to avoid leaking the padding
* validity through timing. RSA keys are small enough that all the * validity through timing. RSA keys are small enough that all the
* size_t values involved fit in unsigned int. */ * size_t values involved fit in unsigned int. */
plaintext_size = mbedtls_cf_uint_if( plaintext_size = mbedtls_ct_uint_if(
bad, (unsigned) plaintext_max_size, bad, (unsigned) plaintext_max_size,
(unsigned) ( ilen - pad_count - 3 ) ); (unsigned) ( ilen - pad_count - 3 ) );
/* Set output_too_large to 0 if the plaintext fits in the output /* Set output_too_large to 0 if the plaintext fits in the output
* buffer and to 1 otherwise. */ * buffer and to 1 otherwise. */
output_too_large = mbedtls_cf_size_gt( plaintext_size, output_too_large = mbedtls_ct_size_gt( plaintext_size,
plaintext_max_size ); plaintext_max_size );
/* Set ret without branches to avoid timing attacks. Return: /* Set ret without branches to avoid timing attacks. Return:
@ -704,9 +704,9 @@ int mbedtls_cf_rsaes_pkcs1_v15_unpadding( int mode,
* - OUTPUT_TOO_LARGE if the padding is good but the decrypted * - OUTPUT_TOO_LARGE if the padding is good but the decrypted
* plaintext does not fit in the output buffer. * plaintext does not fit in the output buffer.
* - 0 if the padding is correct. */ * - 0 if the padding is correct. */
ret = - (int) mbedtls_cf_uint_if( ret = - (int) mbedtls_ct_uint_if(
bad, - MBEDTLS_ERR_RSA_INVALID_PADDING, bad, - MBEDTLS_ERR_RSA_INVALID_PADDING,
mbedtls_cf_uint_if( output_too_large, mbedtls_ct_uint_if( output_too_large,
- MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE, - MBEDTLS_ERR_RSA_OUTPUT_TOO_LARGE,
0 ) ); 0 ) );
@ -716,7 +716,7 @@ int mbedtls_cf_rsaes_pkcs1_v15_unpadding( int mode,
* from the same buffer whether the padding is good or not to * from the same buffer whether the padding is good or not to
* avoid leaking the padding validity through overall timing or * avoid leaking the padding validity through overall timing or
* through memory or cache access patterns. */ * through memory or cache access patterns. */
bad = mbedtls_cf_uint_mask( bad | output_too_large ); bad = mbedtls_ct_uint_mask( bad | output_too_large );
for( i = 11; i < ilen; i++ ) for( i = 11; i < ilen; i++ )
input[i] &= ~bad; input[i] &= ~bad;
@ -724,7 +724,7 @@ int mbedtls_cf_rsaes_pkcs1_v15_unpadding( int mode,
* Copy anyway to avoid revealing the length through timing, because * Copy anyway to avoid revealing the length through timing, because
* revealing the length is as bad as revealing the padding validity * revealing the length is as bad as revealing the padding validity
* for a Bleichenbacher attack. */ * for a Bleichenbacher attack. */
plaintext_size = mbedtls_cf_uint_if( output_too_large, plaintext_size = mbedtls_ct_uint_if( output_too_large,
(unsigned) plaintext_max_size, (unsigned) plaintext_max_size,
(unsigned) plaintext_size ); (unsigned) plaintext_size );
@ -734,7 +734,7 @@ int mbedtls_cf_rsaes_pkcs1_v15_unpadding( int mode,
* does not depend on the plaintext size. After this move, the * does not depend on the plaintext size. After this move, the
* starting location of the plaintext is no longer sensitive * starting location of the plaintext is no longer sensitive
* information. */ * information. */
mbedtls_cf_mem_move_to_left( input + ilen - plaintext_max_size, mbedtls_ct_mem_move_to_left( input + ilen - plaintext_max_size,
plaintext_max_size, plaintext_max_size,
plaintext_max_size - plaintext_size ); plaintext_max_size - plaintext_size );

24
library/constant_time.h
View File

@ -44,7 +44,7 @@
* *
* \return Zero if \p value is zero, otherwise all-bits-one. * \return Zero if \p value is zero, otherwise all-bits-one.
*/ */
unsigned mbedtls_cf_uint_mask( unsigned value ); unsigned mbedtls_ct_uint_mask( unsigned value );
#if defined(MBEDTLS_SSL_SOME_SUITES_USE_TLS_CBC) #if defined(MBEDTLS_SSL_SOME_SUITES_USE_TLS_CBC)
@ -59,7 +59,7 @@ unsigned mbedtls_cf_uint_mask( unsigned value );
* *
* \return Zero if \p value is zero, otherwise all-bits-one. * \return Zero if \p value is zero, otherwise all-bits-one.
*/ */
size_t mbedtls_cf_size_mask( size_t value ); size_t mbedtls_ct_size_mask( size_t value );
#endif /* MBEDTLS_SSL_SOME_SUITES_USE_TLS_CBC */ #endif /* MBEDTLS_SSL_SOME_SUITES_USE_TLS_CBC */
@ -76,7 +76,7 @@ size_t mbedtls_cf_size_mask( size_t value );
* *
* \return Zero if \p value is zero, otherwise all-bits-one. * \return Zero if \p value is zero, otherwise all-bits-one.
*/ */
mbedtls_mpi_uint mbedtls_cf_mpi_uint_mask( mbedtls_mpi_uint value ); mbedtls_mpi_uint mbedtls_ct_mpi_uint_mask( mbedtls_mpi_uint value );
#endif /* MBEDTLS_BIGNUM_C */ #endif /* MBEDTLS_BIGNUM_C */
@ -95,7 +95,7 @@ mbedtls_mpi_uint mbedtls_cf_mpi_uint_mask( mbedtls_mpi_uint value );
* \return All-bits-one if \p x is greater or equal than \p y, * \return All-bits-one if \p x is greater or equal than \p y,
* otherwise zero. * otherwise zero.
*/ */
size_t mbedtls_cf_size_mask_ge( size_t x, size_t mbedtls_ct_size_mask_ge( size_t x,
size_t y ); size_t y );
#endif /* MBEDTLS_SSL_SOME_SUITES_USE_TLS_CBC */ #endif /* MBEDTLS_SSL_SOME_SUITES_USE_TLS_CBC */
@ -111,7 +111,7 @@ size_t mbedtls_cf_size_mask_ge( size_t x,
* *
* \return 1 if \p x equals to \p y, otherwise 0. * \return 1 if \p x equals to \p y, otherwise 0.
*/ */
unsigned mbedtls_cf_size_bool_eq( size_t x, unsigned mbedtls_ct_size_bool_eq( size_t x,
size_t y ); size_t y );
#if defined(MBEDTLS_BIGNUM_C) #if defined(MBEDTLS_BIGNUM_C)
@ -126,7 +126,7 @@ unsigned mbedtls_cf_size_bool_eq( size_t x,
* *
* \return 1 if \p x is less than \p y, otherwise 0. * \return 1 if \p x is less than \p y, otherwise 0.
*/ */
unsigned mbedtls_cf_mpi_uint_lt( const mbedtls_mpi_uint x, unsigned mbedtls_ct_mpi_uint_lt( const mbedtls_mpi_uint x,
const mbedtls_mpi_uint y ); const mbedtls_mpi_uint y );
#endif /* MBEDTLS_BIGNUM_C */ #endif /* MBEDTLS_BIGNUM_C */
@ -142,7 +142,7 @@ unsigned mbedtls_cf_mpi_uint_lt( const mbedtls_mpi_uint x,
* *
* \return \c if1 if \p condition is nonzero, otherwise \c if0. * \return \c if1 if \p condition is nonzero, otherwise \c if0.
*/ */
unsigned mbedtls_cf_uint_if( unsigned condition, unsigned mbedtls_ct_uint_if( unsigned condition,
unsigned if1, unsigned if1,
unsigned if0 ); unsigned if0 );
@ -160,7 +160,7 @@ unsigned mbedtls_cf_uint_if( unsigned condition,
* initialized MPI. * initialized MPI.
* \param condition Condition to test, must be 0 or 1. * \param condition Condition to test, must be 0 or 1.
*/ */
void mbedtls_cf_mpi_uint_cond_assign( size_t n, void mbedtls_ct_mpi_uint_cond_assign( size_t n,
mbedtls_mpi_uint *dest, mbedtls_mpi_uint *dest,
const mbedtls_mpi_uint *src, const mbedtls_mpi_uint *src,
unsigned char condition ); unsigned char condition );
@ -180,7 +180,7 @@ void mbedtls_cf_mpi_uint_cond_assign( size_t n,
* \param c1 The first value to analyze in the condition. * \param c1 The first value to analyze in the condition.
* \param c2 The second value to analyze in the condition. * \param c2 The second value to analyze in the condition.
*/ */
void mbedtls_cf_memcpy_if_eq( unsigned char *dest, void mbedtls_ct_memcpy_if_eq( unsigned char *dest,
const unsigned char *src, const unsigned char *src,
size_t len, size_t len,
size_t c1, size_t c2 ); size_t c1, size_t c2 );
@ -204,7 +204,7 @@ void mbedtls_cf_memcpy_if_eq( unsigned char *dest,
* \param offset_max The maximal value of \p offset. * \param offset_max The maximal value of \p offset.
* \param len The number of bytes to copy. * \param len The number of bytes to copy.
*/ */
void mbedtls_cf_memcpy_offset( unsigned char *dest, void mbedtls_ct_memcpy_offset( unsigned char *dest,
const unsigned char *src, const unsigned char *src,
size_t offset, size_t offset,
size_t offset_min, size_t offset_min,
@ -247,7 +247,7 @@ void mbedtls_cf_memcpy_offset( unsigned char *dest,
* \retval #MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED * \retval #MBEDTLS_ERR_PLATFORM_HW_ACCEL_FAILED
* The hardware accelerator failed. * The hardware accelerator failed.
*/ */
int mbedtls_cf_hmac( mbedtls_md_context_t *ctx, int mbedtls_ct_hmac( mbedtls_md_context_t *ctx,
const unsigned char *add_data, const unsigned char *add_data,
size_t add_data_len, size_t add_data_len,
const unsigned char *data, const unsigned char *data,
@ -288,7 +288,7 @@ int mbedtls_cf_hmac( mbedtls_md_context_t *ctx,
* \return #MBEDTLS_ERR_RSA_INVALID_PADDING * \return #MBEDTLS_ERR_RSA_INVALID_PADDING
* The input doesn't contain properly formatted padding. * The input doesn't contain properly formatted padding.
*/ */
int mbedtls_cf_rsaes_pkcs1_v15_unpadding( int mode, int mbedtls_ct_rsaes_pkcs1_v15_unpadding( int mode,
unsigned char *input, unsigned char *input,
size_t ilen, size_t ilen,
unsigned char *output, unsigned char *output,

4
library/nist_kw.c
View File

@ -379,7 +379,7 @@ int mbedtls_nist_kw_unwrap( mbedtls_nist_kw_context *ctx,
goto cleanup; goto cleanup;
/* Check ICV in "constant-time" */ /* Check ICV in "constant-time" */
diff = mbedtls_cf_memcmp( NIST_KW_ICV1, A, KW_SEMIBLOCK_LENGTH ); diff = mbedtls_ct_memcmp( NIST_KW_ICV1, A, KW_SEMIBLOCK_LENGTH );
if( diff != 0 ) if( diff != 0 )
{ {
@ -428,7 +428,7 @@ int mbedtls_nist_kw_unwrap( mbedtls_nist_kw_context *ctx,
} }
/* Check ICV in "constant-time" */ /* Check ICV in "constant-time" */
diff = mbedtls_cf_memcmp( NIST_KW_ICV2, A, KW_SEMIBLOCK_LENGTH / 2 ); diff = mbedtls_ct_memcmp( NIST_KW_ICV2, A, KW_SEMIBLOCK_LENGTH / 2 );
if( diff != 0 ) if( diff != 0 )
{ {

6
library/rsa.c
View File

@ -1518,7 +1518,7 @@ int mbedtls_rsa_rsaes_pkcs1_v15_decrypt( mbedtls_rsa_context *ctx,
if( ret != 0 ) if( ret != 0 )
goto cleanup; goto cleanup;
ret = mbedtls_cf_rsaes_pkcs1_v15_unpadding( mode, buf, ilen, ret = mbedtls_ct_rsaes_pkcs1_v15_unpadding( mode, buf, ilen,
output, output_max_len, olen ); output, output_max_len, olen );
cleanup: cleanup:
@ -1933,7 +1933,7 @@ int mbedtls_rsa_rsassa_pkcs1_v15_sign( mbedtls_rsa_context *ctx,
MBEDTLS_MPI_CHK( mbedtls_rsa_private( ctx, f_rng, p_rng, sig, sig_try ) ); MBEDTLS_MPI_CHK( mbedtls_rsa_private( ctx, f_rng, p_rng, sig, sig_try ) );
MBEDTLS_MPI_CHK( mbedtls_rsa_public( ctx, sig_try, verif ) ); MBEDTLS_MPI_CHK( mbedtls_rsa_public( ctx, sig_try, verif ) );
if( mbedtls_cf_memcmp( verif, sig, ctx->len ) != 0 ) if( mbedtls_ct_memcmp( verif, sig, ctx->len ) != 0 )
{ {
ret = MBEDTLS_ERR_RSA_PRIVATE_FAILED; ret = MBEDTLS_ERR_RSA_PRIVATE_FAILED;
goto cleanup; goto cleanup;
@ -2231,7 +2231,7 @@ int mbedtls_rsa_rsassa_pkcs1_v15_verify( mbedtls_rsa_context *ctx,
* Compare * Compare
*/ */
if( ( ret = mbedtls_cf_memcmp( encoded, encoded_expected, if( ( ret = mbedtls_ct_memcmp( encoded, encoded_expected,
sig_len ) ) != 0 ) sig_len ) ) != 0 )
{ {
ret = MBEDTLS_ERR_RSA_VERIFY_FAILED; ret = MBEDTLS_ERR_RSA_VERIFY_FAILED;

4
library/ssl_cli.c
View File

@ -1459,9 +1459,9 @@ static int ssl_parse_renegotiation_info( mbedtls_ssl_context *ssl,
/* Check verify-data in constant-time. The length OTOH is no secret */ /* Check verify-data in constant-time. The length OTOH is no secret */
if( len != 1 + ssl->verify_data_len * 2 || if( len != 1 + ssl->verify_data_len * 2 ||
buf[0] != ssl->verify_data_len * 2 || buf[0] != ssl->verify_data_len * 2 ||
mbedtls_cf_memcmp( buf + 1, mbedtls_ct_memcmp( buf + 1,
ssl->own_verify_data, ssl->verify_data_len ) != 0 || ssl->own_verify_data, ssl->verify_data_len ) != 0 ||
mbedtls_cf_memcmp( buf + 1 + ssl->verify_data_len, mbedtls_ct_memcmp( buf + 1 + ssl->verify_data_len,
ssl->peer_verify_data, ssl->verify_data_len ) != 0 ) ssl->peer_verify_data, ssl->verify_data_len ) != 0 )
{ {
MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching renegotiation info" ) ); MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching renegotiation info" ) );

2
library/ssl_cookie.c
View File

@ -225,7 +225,7 @@ int mbedtls_ssl_cookie_check( void *p_ctx,
if( ret != 0 ) if( ret != 0 )
return( ret ); return( ret );
if( mbedtls_cf_memcmp( cookie + 4, ref_hmac, sizeof( ref_hmac ) ) != 0 ) if( mbedtls_ct_memcmp( cookie + 4, ref_hmac, sizeof( ref_hmac ) ) != 0 )
return( -1 ); return( -1 );
#if defined(MBEDTLS_HAVE_TIME) #if defined(MBEDTLS_HAVE_TIME)

22
library/ssl_msg.c
View File

@ -1282,7 +1282,7 @@ int mbedtls_ssl_decrypt_buf( mbedtls_ssl_context const *ssl,
* *
* Afterwards, we know that data + data_len is followed by at * Afterwards, we know that data + data_len is followed by at
* least maclen Bytes, which justifies the call to * least maclen Bytes, which justifies the call to
* mbedtls_cf_memcmp() below. * mbedtls_ct_memcmp() below.
* *
* Further, we still know that data_len > minlen */ * Further, we still know that data_len > minlen */
rec->data_len -= transform->maclen; rec->data_len -= transform->maclen;
@ -1305,7 +1305,7 @@ int mbedtls_ssl_decrypt_buf( mbedtls_ssl_context const *ssl,
transform->maclen ); transform->maclen );
/* Compare expected MAC with MAC at the end of the record. */ /* Compare expected MAC with MAC at the end of the record. */
if( mbedtls_cf_memcmp( data + rec->data_len, mac_expect, if( mbedtls_ct_memcmp( data + rec->data_len, mac_expect,
transform->maclen ) != 0 ) transform->maclen ) != 0 )
{ {
MBEDTLS_SSL_DEBUG_MSG( 1, ( "message mac does not match" ) ); MBEDTLS_SSL_DEBUG_MSG( 1, ( "message mac does not match" ) );
@ -1384,7 +1384,7 @@ int mbedtls_ssl_decrypt_buf( mbedtls_ssl_context const *ssl,
if( auth_done == 1 ) if( auth_done == 1 )
{ {
const size_t mask = mbedtls_cf_size_mask_ge( const size_t mask = mbedtls_ct_size_mask_ge(
rec->data_len, rec->data_len,
padlen + 1 ); padlen + 1 );
correct &= mask; correct &= mask;
@ -1404,7 +1404,7 @@ int mbedtls_ssl_decrypt_buf( mbedtls_ssl_context const *ssl,
} }
#endif #endif
const size_t mask = mbedtls_cf_size_mask_ge( const size_t mask = mbedtls_ct_size_mask_ge(
rec->data_len, rec->data_len,
transform->maclen + padlen + 1 ); transform->maclen + padlen + 1 );
correct &= mask; correct &= mask;
@ -1460,18 +1460,18 @@ int mbedtls_ssl_decrypt_buf( mbedtls_ssl_context const *ssl,
/* pad_count += (idx >= padding_idx) && /* pad_count += (idx >= padding_idx) &&
* (check[idx] == padlen - 1); * (check[idx] == padlen - 1);
*/ */
const size_t mask = mbedtls_cf_size_mask_ge( idx, padding_idx ); const size_t mask = mbedtls_ct_size_mask_ge( idx, padding_idx );
const size_t equal = mbedtls_cf_size_bool_eq( check[idx], const size_t equal = mbedtls_ct_size_bool_eq( check[idx],
padlen - 1 ); padlen - 1 );
pad_count += mask & equal; pad_count += mask & equal;
} }
correct &= mbedtls_cf_size_bool_eq( pad_count, padlen ); correct &= mbedtls_ct_size_bool_eq( pad_count, padlen );
#if defined(MBEDTLS_SSL_DEBUG_ALL) #if defined(MBEDTLS_SSL_DEBUG_ALL)
if( padlen > 0 && correct == 0 ) if( padlen > 0 && correct == 0 )
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad padding byte detected" ) ); MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad padding byte detected" ) );
#endif #endif
padlen &= mbedtls_cf_size_mask( correct ); padlen &= mbedtls_ct_size_mask( correct );
} }
else else
#endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \ #endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \
@ -1555,7 +1555,7 @@ int mbedtls_ssl_decrypt_buf( mbedtls_ssl_context const *ssl,
const size_t max_len = rec->data_len + padlen; const size_t max_len = rec->data_len + padlen;
const size_t min_len = ( max_len > 256 ) ? max_len - 256 : 0; const size_t min_len = ( max_len > 256 ) ? max_len - 256 : 0;
ret = mbedtls_cf_hmac( &transform->md_ctx_dec, ret = mbedtls_ct_hmac( &transform->md_ctx_dec,
add_data, add_data_len, add_data, add_data_len,
data, rec->data_len, min_len, max_len, data, rec->data_len, min_len, max_len,
mac_expect ); mac_expect );
@ -1565,7 +1565,7 @@ int mbedtls_ssl_decrypt_buf( mbedtls_ssl_context const *ssl,
return( ret ); return( ret );
} }
mbedtls_cf_memcpy_offset( mac_peer, data, mbedtls_ct_memcpy_offset( mac_peer, data,
rec->data_len, rec->data_len,
min_len, max_len, min_len, max_len,
transform->maclen ); transform->maclen );
@ -1583,7 +1583,7 @@ int mbedtls_ssl_decrypt_buf( mbedtls_ssl_context const *ssl,
MBEDTLS_SSL_DEBUG_BUF( 4, "message mac", mac_peer, transform->maclen ); MBEDTLS_SSL_DEBUG_BUF( 4, "message mac", mac_peer, transform->maclen );
#endif #endif
if( mbedtls_cf_memcmp( mac_peer, mac_expect, if( mbedtls_ct_memcmp( mac_peer, mac_expect,
transform->maclen ) != 0 ) transform->maclen ) != 0 )
{ {
#if defined(MBEDTLS_SSL_DEBUG_ALL) #if defined(MBEDTLS_SSL_DEBUG_ALL)

6
library/ssl_srv.c
View File

@ -198,7 +198,7 @@ static int ssl_parse_renegotiation_info( mbedtls_ssl_context *ssl,
/* Check verify-data in constant-time. The length OTOH is no secret */ /* Check verify-data in constant-time. The length OTOH is no secret */
if( len != 1 + ssl->verify_data_len || if( len != 1 + ssl->verify_data_len ||
buf[0] != ssl->verify_data_len || buf[0] != ssl->verify_data_len ||
mbedtls_cf_memcmp( buf + 1, ssl->peer_verify_data, mbedtls_ct_memcmp( buf + 1, ssl->peer_verify_data,
ssl->verify_data_len ) != 0 ) ssl->verify_data_len ) != 0 )
{ {
MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching renegotiation info" ) ); MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching renegotiation info" ) );
@ -3973,7 +3973,7 @@ static int ssl_parse_encrypted_pms( mbedtls_ssl_context *ssl,
diff |= peer_pms[1] ^ ver[1]; diff |= peer_pms[1] ^ ver[1];
/* mask = diff ? 0xff : 0x00 using bit operations to avoid branches */ /* mask = diff ? 0xff : 0x00 using bit operations to avoid branches */
mask = mbedtls_cf_uint_mask( diff ); mask = mbedtls_ct_uint_mask( diff );
/* /*
* Protection against Bleichenbacher's attack: invalid PKCS#1 v1.5 padding * Protection against Bleichenbacher's attack: invalid PKCS#1 v1.5 padding
@ -4056,7 +4056,7 @@ static int ssl_parse_client_psk_identity( mbedtls_ssl_context *ssl, unsigned cha
/* Identity is not a big secret since clients send it in the clear, /* Identity is not a big secret since clients send it in the clear,
* but treat it carefully anyway, just in case */ * but treat it carefully anyway, just in case */
if( n != ssl->conf->psk_identity_len || if( n != ssl->conf->psk_identity_len ||
mbedtls_cf_memcmp( ssl->conf->psk_identity, *p, n ) != 0 ) mbedtls_ct_memcmp( ssl->conf->psk_identity, *p, n ) != 0 )
{ {
ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY; ret = MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY;
} }

2
library/ssl_tls.c
View File

@ -3604,7 +3604,7 @@ int mbedtls_ssl_parse_finished( mbedtls_ssl_context *ssl )
return( MBEDTLS_ERR_SSL_BAD_HS_FINISHED ); return( MBEDTLS_ERR_SSL_BAD_HS_FINISHED );
} }
if( mbedtls_cf_memcmp( ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl ), if( mbedtls_ct_memcmp( ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl ),
buf, hash_len ) != 0 ) buf, hash_len ) != 0 )
{ {
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad finished message" ) ); MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad finished message" ) );

6
tests/suites/test_suite_ssl.function
View File

@ -4428,7 +4428,7 @@ void resize_buffers_renegotiate_mfl( int mfl, int legacy_renegotiation,
void ssl_cf_hmac( int hash ) void ssl_cf_hmac( int hash )
{ {
/* /*
* Test the function mbedtls_cf_hmac() against a reference * Test the function mbedtls_ct_hmac() against a reference
* implementation. * implementation.
*/ */
mbedtls_md_context_t ctx, ref_ctx; mbedtls_md_context_t ctx, ref_ctx;
@ -4487,7 +4487,7 @@ void ssl_cf_hmac( int hash )
/* Get the function's result */ /* Get the function's result */
TEST_CF_SECRET( &in_len, sizeof( in_len ) ); TEST_CF_SECRET( &in_len, sizeof( in_len ) );
TEST_EQUAL( 0, mbedtls_cf_hmac( &ctx, add_data, sizeof( add_data ), TEST_EQUAL( 0, mbedtls_ct_hmac( &ctx, add_data, sizeof( add_data ),
data, in_len, data, in_len,
min_in_len, max_in_len, min_in_len, max_in_len,
out ) ); out ) );
@ -4537,7 +4537,7 @@ void ssl_cf_memcpy_offset( int offset_min, int offset_max, int len )
mbedtls_test_set_step( (int) secret ); mbedtls_test_set_step( (int) secret );
TEST_CF_SECRET( &secret, sizeof( secret ) ); TEST_CF_SECRET( &secret, sizeof( secret ) );
mbedtls_cf_memcpy_offset( dst, src, secret, mbedtls_ct_memcpy_offset( dst, src, secret,
offset_min, offset_max, len ); offset_min, offset_max, len );
TEST_CF_PUBLIC( &secret, sizeof( secret ) ); TEST_CF_PUBLIC( &secret, sizeof( secret ) );
TEST_CF_PUBLIC( dst, len ); TEST_CF_PUBLIC( dst, len );