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Merge remote-tracking branch 'restricted/pr/494' into mbedtls-2.7

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This commit is contained in:
Simon Butcher 2018-07-24 23:40:53 +01:00
commit 7daacda940
6 changed files with 263 additions and 90 deletions
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54
library/md5.c
View file

@ -313,14 +313,6 @@ void mbedtls_md5_update( mbedtls_md5_context *ctx,
}
#endif
static const unsigned char md5_padding[64] =
{
0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
/*
* MD5 final digest
*/
@ -328,26 +320,48 @@ int mbedtls_md5_finish_ret( mbedtls_md5_context *ctx,
unsigned char output[16] )
{
int ret;
uint32_t last, padn;
uint32_t used;
uint32_t high, low;
unsigned char msglen[8];
/*
* Add padding: 0x80 then 0x00 until 8 bytes remain for the length
*/
used = ctx->total[0] & 0x3F;
ctx->buffer[used++] = 0x80;
if( used <= 56 )
{
/* Enough room for padding + length in current block */
memset( ctx->buffer + used, 0, 56 - used );
}
else
{
/* We'll need an extra block */
memset( ctx->buffer + used, 0, 64 - used );
if( ( ret = mbedtls_internal_md5_process( ctx, ctx->buffer ) ) != 0 )
return( ret );
memset( ctx->buffer, 0, 56 );
}
/*
* Add message length
*/
high = ( ctx->total[0] >> 29 )
| ( ctx->total[1] << 3 );
low = ( ctx->total[0] << 3 );
PUT_UINT32_LE( low, msglen, 0 );
PUT_UINT32_LE( high, msglen, 4 );
PUT_UINT32_LE( low, ctx->buffer, 56 );
PUT_UINT32_LE( high, ctx->buffer, 60 );
last = ctx->total[0] & 0x3F;
padn = ( last < 56 ) ? ( 56 - last ) : ( 120 - last );
if( ( ret = mbedtls_md5_update_ret( ctx, md5_padding, padn ) ) != 0 )
return( ret );
if( ( ret = mbedtls_md5_update_ret( ctx, msglen, 8 ) ) != 0 )
return( ret );
if( ( ret = mbedtls_internal_md5_process( ctx, ctx->buffer ) ) != 0 )
return( ret );
/*
* Output final state
*/
PUT_UINT32_LE( ctx->state[0], output, 0 );
PUT_UINT32_LE( ctx->state[1], output, 4 );
PUT_UINT32_LE( ctx->state[2], output, 8 );

51
library/sha1.c
View file

@ -346,14 +346,6 @@ void mbedtls_sha1_update( mbedtls_sha1_context *ctx,
}
#endif
static const unsigned char sha1_padding[64] =
{
0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
/*
* SHA-1 final digest
*/
@ -361,25 +353,48 @@ int mbedtls_sha1_finish_ret( mbedtls_sha1_context *ctx,
unsigned char output[20] )
{
int ret;
uint32_t last, padn;
uint32_t used;
uint32_t high, low;
unsigned char msglen[8];
/*
* Add padding: 0x80 then 0x00 until 8 bytes remain for the length
*/
used = ctx->total[0] & 0x3F;
ctx->buffer[used++] = 0x80;
if( used <= 56 )
{
/* Enough room for padding + length in current block */
memset( ctx->buffer + used, 0, 56 - used );
}
else
{
/* We'll need an extra block */
memset( ctx->buffer + used, 0, 64 - used );
if( ( ret = mbedtls_internal_sha1_process( ctx, ctx->buffer ) ) != 0 )
return( ret );
memset( ctx->buffer, 0, 56 );
}
/*
* Add message length
*/
high = ( ctx->total[0] >> 29 )
| ( ctx->total[1] << 3 );
low = ( ctx->total[0] << 3 );
PUT_UINT32_BE( high, msglen, 0 );
PUT_UINT32_BE( low, msglen, 4 );
PUT_UINT32_BE( high, ctx->buffer, 56 );
PUT_UINT32_BE( low, ctx->buffer, 60 );
last = ctx->total[0] & 0x3F;
padn = ( last < 56 ) ? ( 56 - last ) : ( 120 - last );
if( ( ret = mbedtls_sha1_update_ret( ctx, sha1_padding, padn ) ) != 0 )
return( ret );
if( ( ret = mbedtls_sha1_update_ret( ctx, msglen, 8 ) ) != 0 )
if( ( ret = mbedtls_internal_sha1_process( ctx, ctx->buffer ) ) != 0 )
return( ret );
/*
* Output final state
*/
PUT_UINT32_BE( ctx->state[0], output, 0 );
PUT_UINT32_BE( ctx->state[1], output, 4 );
PUT_UINT32_BE( ctx->state[2], output, 8 );

52
library/sha256.c
View file

@ -315,14 +315,6 @@ void mbedtls_sha256_update( mbedtls_sha256_context *ctx,
}
#endif
static const unsigned char sha256_padding[64] =
{
0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
/*
* SHA-256 final digest
*/
@ -330,26 +322,48 @@ int mbedtls_sha256_finish_ret( mbedtls_sha256_context *ctx,
unsigned char output[32] )
{
int ret;
uint32_t last, padn;
uint32_t used;
uint32_t high, low;
unsigned char msglen[8];
/*
* Add padding: 0x80 then 0x00 until 8 bytes remain for the length
*/
used = ctx->total[0] & 0x3F;
ctx->buffer[used++] = 0x80;
if( used <= 56 )
{
/* Enough room for padding + length in current block */
memset( ctx->buffer + used, 0, 56 - used );
}
else
{
/* We'll need an extra block */
memset( ctx->buffer + used, 0, 64 - used );
if( ( ret = mbedtls_internal_sha256_process( ctx, ctx->buffer ) ) != 0 )
return( ret );
memset( ctx->buffer, 0, 56 );
}
/*
* Add message length
*/
high = ( ctx->total[0] >> 29 )
| ( ctx->total[1] << 3 );
low = ( ctx->total[0] << 3 );
PUT_UINT32_BE( high, msglen, 0 );
PUT_UINT32_BE( low, msglen, 4 );
PUT_UINT32_BE( high, ctx->buffer, 56 );
PUT_UINT32_BE( low, ctx->buffer, 60 );
last = ctx->total[0] & 0x3F;
padn = ( last < 56 ) ? ( 56 - last ) : ( 120 - last );
if( ( ret = mbedtls_sha256_update_ret( ctx, sha256_padding, padn ) ) != 0 )
return( ret );
if( ( ret = mbedtls_sha256_update_ret( ctx, msglen, 8 ) ) != 0 )
if( ( ret = mbedtls_internal_sha256_process( ctx, ctx->buffer ) ) != 0 )
return( ret );
/*
* Output final state
*/
PUT_UINT32_BE( ctx->state[0], output, 0 );
PUT_UINT32_BE( ctx->state[1], output, 4 );
PUT_UINT32_BE( ctx->state[2], output, 8 );

58
library/sha512.c
View file

@ -345,18 +345,6 @@ void mbedtls_sha512_update( mbedtls_sha512_context *ctx,
}
#endif
static const unsigned char sha512_padding[128] =
{
0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
/*
* SHA-512 final digest
*/
@ -364,26 +352,48 @@ int mbedtls_sha512_finish_ret( mbedtls_sha512_context *ctx,
unsigned char output[64] )
{
int ret;
size_t last, padn;
unsigned used;
uint64_t high, low;
unsigned char msglen[16];
/*
* Add padding: 0x80 then 0x00 until 16 bytes remain for the length
*/
used = ctx->total[0] & 0x7F;
ctx->buffer[used++] = 0x80;
if( used <= 112 )
{
/* Enough room for padding + length in current block */
memset( ctx->buffer + used, 0, 112 - used );
}
else
{
/* We'll need an extra block */
memset( ctx->buffer + used, 0, 128 - used );
if( ( ret = mbedtls_internal_sha512_process( ctx, ctx->buffer ) ) != 0 )
return( ret );
memset( ctx->buffer, 0, 112 );
}
/*
* Add message length
*/
high = ( ctx->total[0] >> 61 )
| ( ctx->total[1] << 3 );
low = ( ctx->total[0] << 3 );
PUT_UINT64_BE( high, msglen, 0 );
PUT_UINT64_BE( low, msglen, 8 );
PUT_UINT64_BE( high, ctx->buffer, 112 );
PUT_UINT64_BE( low, ctx->buffer, 120 );
last = (size_t)( ctx->total[0] & 0x7F );
padn = ( last < 112 ) ? ( 112 - last ) : ( 240 - last );
if( ( ret = mbedtls_sha512_update_ret( ctx, sha512_padding, padn ) ) != 0 )
return( ret );
if( ( ret = mbedtls_sha512_update_ret( ctx, msglen, 16 ) ) != 0 )
return( ret );
if( ( ret = mbedtls_internal_sha512_process( ctx, ctx->buffer ) ) != 0 )
return( ret );
/*
* Output final state
*/
PUT_UINT64_BE( ctx->state[0], output, 0 );
PUT_UINT64_BE( ctx->state[1], output, 8 );
PUT_UINT64_BE( ctx->state[2], output, 16 );

105
library/ssl_tls.c
View file

@ -1281,6 +1281,27 @@ static void ssl_mac( mbedtls_md_context_t *md_ctx,
#define SSL_SOME_MODES_USE_MAC
#endif
/* The function below is only used in the Lucky 13 counter-measure in
* ssl_decrypt_buf(). These are the defines that guard the call site. */
#if defined(SSL_SOME_MODES_USE_MAC) && \
( defined(MBEDTLS_SSL_PROTO_TLS1) || \
defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
defined(MBEDTLS_SSL_PROTO_TLS1_2) )
/* This function makes sure every byte in the memory region is accessed
* (in ascending addresses order) */
static void ssl_read_memory( unsigned char *p, size_t len )
{
unsigned char acc = 0;
volatile unsigned char force;
for( ; len != 0; p++, len-- )
acc ^= *p;
force = acc;
(void) force;
}
#endif /* SSL_SOME_MODES_USE_MAC && ( TLS1 || TLS1_1 || TLS1_2 ) */
/*
* Encryption/decryption functions
*/
@ -1956,8 +1977,10 @@ static int ssl_decrypt_buf( mbedtls_ssl_context *ssl )
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
#if defined(MBEDTLS_SSL_DEBUG_ALL)
MBEDTLS_SSL_DEBUG_BUF( 4, "raw buffer after decryption",
ssl->in_msg, ssl->in_msglen );
#endif
/*
* Authenticate if not done yet.
@ -1990,20 +2013,69 @@ static int ssl_decrypt_buf( mbedtls_ssl_context *ssl )
{
/*
* Process MAC and always update for padlen afterwards to make
* total time independent of padlen
*
* extra_run compensates MAC check for padlen
* total time independent of padlen.
*
* Known timing attacks:
* - Lucky Thirteen (http://www.isg.rhul.ac.uk/tls/TLStiming.pdf)
*
* We use ( ( Lx + 8 ) / 64 ) to handle 'negative Lx' values
* correctly. (We round down instead of up, so -56 is the correct
* value for our calculations instead of -55)
* To compensate for different timings for the MAC calculation
* depending on how much padding was removed (which is determined
* by padlen), process extra_run more blocks through the hash
* function.
*
* The formula in the paper is
* extra_run = ceil( (L1-55) / 64 ) - ceil( (L2-55) / 64 )
* where L1 is the size of the header plus the decrypted message
* plus CBC padding and L2 is the size of the header plus the
* decrypted message. This is for an underlying hash function
* with 64-byte blocks.
* We use ( (Lx+8) / 64 ) to handle 'negative Lx' values
* correctly. We round down instead of up, so -56 is the correct
* value for our calculations instead of -55.
*
* Repeat the formula rather than defining a block_size variable.
* This avoids requiring division by a variable at runtime
* (which would be marginally less efficient and would require
* linking an extra division function in some builds).
*/
size_t j, extra_run = 0;
extra_run = ( 13 + ssl->in_msglen + padlen + 8 ) / 64 -
( 13 + ssl->in_msglen + 8 ) / 64;
/*
* The next two sizes are the minimum and maximum values of
* in_msglen over all padlen values.
*
* They're independent of padlen, since we previously did
* in_msglen -= padlen.
*
* Note that max_len + maclen is never more than the buffer
* length, as we previously did in_msglen -= maclen too.
*/
const size_t max_len = ssl->in_msglen + padlen;
const size_t min_len = ( max_len > 256 ) ? max_len - 256 : 0;
switch( ssl->transform_in->ciphersuite_info->mac )
{
#if defined(MBEDTLS_MD5_C) || defined(MBEDTLS_SHA1_C) || \
defined(MBEDTLS_SHA256_C)
case MBEDTLS_MD_MD5:
case MBEDTLS_MD_SHA1:
case MBEDTLS_MD_SHA256:
/* 8 bytes of message size, 64-byte compression blocks */
extra_run = ( 13 + ssl->in_msglen + padlen + 8 ) / 64 -
( 13 + ssl->in_msglen + 8 ) / 64;
break;
#endif
#if defined(MBEDTLS_SHA512_C)
case MBEDTLS_MD_SHA384:
/* 16 bytes of message size, 128-byte compression blocks */
extra_run = ( 13 + ssl->in_msglen + padlen + 16 ) / 128 -
( 13 + ssl->in_msglen + 16 ) / 128;
break;
#endif
default:
MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
extra_run &= correct * 0xFF;
@ -2012,12 +2084,25 @@ static int ssl_decrypt_buf( mbedtls_ssl_context *ssl )
mbedtls_md_hmac_update( &ssl->transform_in->md_ctx_dec, ssl->in_len, 2 );
mbedtls_md_hmac_update( &ssl->transform_in->md_ctx_dec, ssl->in_msg,
ssl->in_msglen );
/* Make sure we access everything even when padlen > 0. This
* makes the synchronisation requirements for just-in-time
* Prime+Probe attacks much tighter and hopefully impractical. */
ssl_read_memory( ssl->in_msg + ssl->in_msglen, padlen );
mbedtls_md_hmac_finish( &ssl->transform_in->md_ctx_dec, mac_expect );
/* Call mbedtls_md_process at least once due to cache attacks */
/* Call mbedtls_md_process at least once due to cache attacks
* that observe whether md_process() was called of not */
for( j = 0; j < extra_run + 1; j++ )
mbedtls_md_process( &ssl->transform_in->md_ctx_dec, ssl->in_msg );
mbedtls_md_hmac_reset( &ssl->transform_in->md_ctx_dec );
/* Make sure we access all the memory that could contain the MAC,
* before we check it in the next code block. This makes the
* synchronisation requirements for just-in-time Prime+Probe
* attacks much tighter and hopefully impractical. */
ssl_read_memory( ssl->in_msg + min_len,
max_len - min_len + ssl->transform_in->maclen );
}
else
#endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \
@ -2027,9 +2112,11 @@ static int ssl_decrypt_buf( mbedtls_ssl_context *ssl )
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
#if defined(MBEDTLS_SSL_DEBUG_ALL)
MBEDTLS_SSL_DEBUG_BUF( 4, "expected mac", mac_expect, ssl->transform_in->maclen );
MBEDTLS_SSL_DEBUG_BUF( 4, "message mac", ssl->in_msg + ssl->in_msglen,
ssl->transform_in->maclen );
#endif
if( mbedtls_ssl_safer_memcmp( ssl->in_msg + ssl->in_msglen, mac_expect,
ssl->transform_in->maclen ) != 0 )