Add FI countermeasures to the ssl module

This commit adds mainly buffer pointer and length duplication and checks,
but also some hamming distance and return values checking improvements.
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
This commit is contained in:
Andrzej Kurek 2020-07-06 15:27:34 -04:00
parent 74f7d0f03d
commit 84bde419e1
No known key found for this signature in database
GPG key ID: 89A90840DC388527
3 changed files with 153 additions and 34 deletions

View file

@ -3587,7 +3587,10 @@ static int ssl_out_client_key_exchange_write( mbedtls_ssl_context *ssl,
{
int ret;
unsigned char *p, *end;
volatile unsigned char *buf_dup = buf;
volatile size_t buflen_dup = buflen;
size_t n;
mbedtls_ssl_ciphersuite_handle_t ciphersuite_info =
mbedtls_ssl_handshake_get_ciphersuite( ssl->handshake );
@ -3870,7 +3873,12 @@ static int ssl_out_client_key_exchange_write( mbedtls_ssl_context *ssl,
}
*olen = p - buf;
return( 0 );
/* Secure against buffer substitution */
if( buf_dup == buf && buflen_dup == buflen )
{
return( 0 );
}
return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
}
static int ssl_out_client_key_exchange_postprocess( mbedtls_ssl_context *ssl )

View file

@ -3269,13 +3269,19 @@ static int ssl_resume_server_key_exchange( mbedtls_ssl_context *ssl,
- sig_start );
int ret = ssl->conf->f_async_resume( ssl,
sig_start, signature_len, sig_max_len );
volatile size_t *signature_len_dup = signature_len;
if( ret != MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS )
{
ssl->handshake->async_in_progress = 0;
mbedtls_ssl_set_async_operation_data( ssl, NULL );
}
MBEDTLS_SSL_DEBUG_RET( 2, "ssl_resume_server_key_exchange", ret );
return( ret );
/* Secure against buffer substitution */
if( signature_len_dup == signature_len )
{
return( ret );
}
return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
}
#endif /* defined(MBEDTLS_KEY_EXCHANGE__WITH_SERVER_SIGNATURE__ENABLED) &&
defined(MBEDTLS_SSL_ASYNC_PRIVATE) */
@ -3678,7 +3684,7 @@ static int ssl_prepare_server_key_exchange( mbedtls_ssl_context *ssl,
{
return( 0 );
}
return MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
}
/* Prepare the ServerKeyExchange message and send it. For ciphersuites
@ -3826,6 +3832,8 @@ static int ssl_parse_client_dh_public( mbedtls_ssl_context *ssl, unsigned char *
const unsigned char *end )
{
int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
unsigned char ** volatile p_dup = p;
volatile const unsigned char *end_dup = end;
size_t n;
/*
@ -3856,7 +3864,12 @@ static int ssl_parse_client_dh_public( mbedtls_ssl_context *ssl, unsigned char *
MBEDTLS_SSL_DEBUG_MPI( 3, "DHM: GY", &ssl->handshake->dhm_ctx.GY );
return( ret );
/* Secure against buffer substitution */
if( p_dup == p && end_dup == end )
{
return( ret );
}
return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
}
#endif /* MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED ||
MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED */
@ -4423,7 +4436,7 @@ static int ssl_in_client_key_exchange_parse( mbedtls_ssl_context *ssl,
{
return( ret );
}
return MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
}
/* Update the handshake state */

View file

@ -232,7 +232,7 @@ exit:
if( buf_dup != buf || buflen_dup != buflen )
{
return MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
}
MBEDTLS_SSL_DEBUG_MSG( 1, ( "<= mbedtls_ssl_check_record" ) );
return( ret );
@ -288,6 +288,9 @@ int mbedtls_ssl_set_cid( mbedtls_ssl_context *ssl,
unsigned char const *own_cid,
size_t own_cid_len )
{
volatile unsigned char const *own_cid_dup = own_cid;
volatile size_t own_cid_len_dup = own_cid_len;
if( MBEDTLS_SSL_TRANSPORT_IS_TLS( ssl->conf->transport ) )
return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
@ -314,7 +317,12 @@ int mbedtls_ssl_set_cid( mbedtls_ssl_context *ssl,
* MBEDTLS_SSL_CID_IN_LEN_MAX at most 255. */
ssl->own_cid_len = (uint8_t) own_cid_len;
return( 0 );
/* Secure against buffer substitution */
if( own_cid_dup == own_cid && own_cid_len_dup == own_cid_len )
{
return( 0 );
}
return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
}
int mbedtls_ssl_get_peer_cid( mbedtls_ssl_context *ssl,
@ -611,7 +619,13 @@ MBEDTLS_NO_INLINE static int ssl3_prf( const unsigned char *secret, size_t slen,
mbedtls_sha1_context sha1;
unsigned char padding[16];
unsigned char sha1sum[20];
((void)label);
volatile const unsigned char *secret_dup = secret;
volatile size_t slen_dup = slen;
volatile const char *label_dup = label;
volatile const unsigned char *random_dup = random;
volatile size_t rlen_dup = rlen;
volatile unsigned char *dstbuf_dup = dstbuf;
volatile size_t dlen_dup = dlen;
mbedtls_md5_init( &md5 );
mbedtls_sha1_init( &sha1 );
@ -656,7 +670,14 @@ exit:
mbedtls_platform_zeroize( padding, sizeof( padding ) );
mbedtls_platform_zeroize( sha1sum, sizeof( sha1sum ) );
return( ret );
/* Secure against buffer substitution */
if( secret_dup == secret && slen_dup == slen && label_dup == label &&
random_dup == random && rlen_dup == rlen && dstbuf_dup == dstbuf &&
dlen_dup == dlen )
{
return( ret );
}
return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
}
#endif /* MBEDTLS_SSL_PROTO_SSL3 */
@ -674,6 +695,13 @@ MBEDTLS_NO_INLINE static int tls1_prf( const unsigned char *secret, size_t slen,
mbedtls_md_handle_t md_info;
mbedtls_md_context_t md_ctx;
int ret;
volatile const unsigned char *secret_dup = secret;
volatile size_t slen_dup = slen;
volatile const char *label_dup = label;
volatile const unsigned char *random_dup = random;
volatile size_t rlen_dup = rlen;
volatile unsigned char *dstbuf_dup = dstbuf;
volatile size_t dlen_dup = dlen;
mbedtls_md_init( &md_ctx );
@ -760,7 +788,14 @@ MBEDTLS_NO_INLINE static int tls1_prf( const unsigned char *secret, size_t slen,
mbedtls_platform_zeroize( tmp, sizeof( tmp ) );
mbedtls_platform_zeroize( h_i, sizeof( h_i ) );
return( 0 );
/* Secure against buffer substitution */
if( secret_dup == secret && slen_dup == slen && label_dup == label &&
random_dup == random && rlen_dup == rlen && dstbuf_dup == dstbuf &&
dlen_dup == dlen )
{
return( 0 );
}
return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
}
#endif /* MBEDTLS_SSL_PROTO_TLS1) || MBEDTLS_SSL_PROTO_TLS1_1 */
@ -783,6 +818,13 @@ int tls_prf_generic( mbedtls_md_type_t md_type,
mbedtls_md_handle_t md_info;
mbedtls_md_context_t md_ctx;
int ret;
volatile const unsigned char *secret_dup = secret;
volatile size_t slen_dup = slen;
volatile const char *label_dup = label;
volatile const unsigned char *random_dup = random;
volatile size_t rlen_dup = rlen;
volatile unsigned char *dstbuf_dup = dstbuf;
volatile size_t dlen_dup = dlen;
mbedtls_md_init( &md_ctx );
@ -842,7 +884,14 @@ int tls_prf_generic( mbedtls_md_type_t md_type,
(void)mbedtls_platform_zeroize( tmp, sizeof( tmp ) );
(void)mbedtls_platform_zeroize( h_i, sizeof( h_i ) );
return( 0 );
/* Secure against buffer substitution */
if( secret_dup == secret && slen_dup == slen && label_dup == label &&
random_dup == random && rlen_dup == rlen && dstbuf_dup == dstbuf &&
dlen_dup == dlen )
{
return( 0 );
}
return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
}
#if defined(MBEDTLS_SHA256_C)
@ -1834,6 +1883,7 @@ static int ssl_compute_master( mbedtls_ssl_handshake_params *handshake,
const mbedtls_ssl_context *ssl )
{
int ret;
volatile unsigned char *master_dup = master;
/* #if !defined(MBEDTLS_DEBUG_C) && !defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET) */
/* ssl = NULL; /\* make sure we don't use it except for debug and EMS *\/ */
@ -1894,8 +1944,12 @@ static int ssl_compute_master( mbedtls_ssl_handshake_params *handshake,
mbedtls_platform_zeroize( handshake->premaster,
sizeof(handshake->premaster) );
return( 0 );
/* Secure against buffer substitution */
if( master_dup == master )
{
return( 0 );
}
return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
}
int mbedtls_ssl_derive_keys( mbedtls_ssl_context *ssl )
@ -2412,22 +2466,33 @@ static int ssl_cid_build_inner_plaintext( unsigned char *content,
size_t pad = ( MBEDTLS_SSL_CID_PADDING_GRANULARITY -
( len + 1 ) % MBEDTLS_SSL_CID_PADDING_GRANULARITY ) %
MBEDTLS_SSL_CID_PADDING_GRANULARITY;
volatile unsigned char *content_dup = content;
volatile size_t *content_size_dup = content_size;
volatile size_t remaining_dup = remaining;
/* Write real content type */
if( remaining == 0 )
return( -1 );
return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
content[ len ] = rec_type;
len++;
remaining--;
if( remaining < pad )
return( -1 );
return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
mbedtls_platform_memset( content + len, 0, pad );
len += pad;
remaining -= pad;
*content_size = len;
return( 0 );
/* Secure against buffer substitution */
if( content_dup == content && content_size_dup == content_size &&
( remaining_dup - 1 - pad ) == remaining )
{
return( 0 );
}
return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
}
/* This function parses a DTLSInnerPlaintext structure.
@ -2572,6 +2637,7 @@ int mbedtls_ssl_encrypt_buf( mbedtls_ssl_context *ssl,
if( rec->cid_len != 0 )
{
int ret = MBEDTLS_ERR_PLATFORM_FAULT_DETECTED;
/*
* Wrap plaintext into DTLSInnerPlaintext structure.
* See ssl_cid_build_inner_plaintext() for more information.
@ -2579,12 +2645,12 @@ int mbedtls_ssl_encrypt_buf( mbedtls_ssl_context *ssl,
* Note that this changes `rec->data_len`, and hence
* `post_avail` needs to be recalculated afterwards.
*/
if( ssl_cid_build_inner_plaintext( data,
&rec->data_len,
post_avail,
rec->type ) != 0 )
if( ( ret = ssl_cid_build_inner_plaintext( data,
&rec->data_len,
post_avail,
rec->type ) ) != 0 )
{
return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
return( ret );
}
rec->type = MBEDTLS_SSL_MSG_CID;
@ -4831,13 +4897,13 @@ static int ssl_bitmask_check( unsigned char *mask, size_t len )
for( i = 0; i < len / 8; i++ )
if( mask[i] != 0xFF )
return( -1 );
return( 0x75555555 );
for( i = 0; i < len % 8; i++ )
if( ( mask[len / 8] & ( 1 << ( 7 - i ) ) ) == 0 )
return( -1 );
return( 0x75555555 );
return( 0 );
return( 0 );
}
/* msg_len does not include the handshake header */
@ -7070,10 +7136,10 @@ static int ssl_check_peer_crt_unchanged( mbedtls_ssl_context *ssl,
mbedtls_x509_crt const * const peer_crt = ssl->session->peer_cert;
if( peer_crt == NULL )
return( -1 );
return( 0x75555555 );
if( peer_crt->raw.len != crt_buf_len )
return( -1 );
return( 0x75555555 );
return( mbedtls_platform_memcmp( peer_crt->raw.p, crt_buf, crt_buf_len ) );
}
@ -7095,16 +7161,16 @@ static int ssl_check_peer_crt_unchanged( mbedtls_ssl_context *ssl,
if( peer_cert_digest == NULL ||
digest_info == MBEDTLS_MD_INVALID_HANDLE )
{
return( -1 );
return( 0x75555555 );
}
digest_len = mbedtls_md_get_size( digest_info );
if( digest_len > MBEDTLS_SSL_PEER_CERT_DIGEST_MAX_LEN )
return( -1 );
return( 0x75555555 );
ret = mbedtls_md( digest_info, crt_buf, crt_buf_len, tmp_digest );
if( ret != 0 )
return( -1 );
return( 0x75555555 );
return( mbedtls_platform_memcmp( tmp_digest, peer_cert_digest, digest_len ) );
}
@ -10869,6 +10935,8 @@ int mbedtls_ssl_read( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len )
{
int ret;
size_t n;
volatile unsigned char *buf_dup = buf;
volatile size_t len_dup = len;
if( ssl == NULL || ssl->conf == NULL )
return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
@ -11182,7 +11250,12 @@ int mbedtls_ssl_read( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len )
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= read" ) );
return( (int) n );
/* Secure against buffer substitution */
if( buf_dup == buf && len_dup == len )
{
return( (int) n );
}
return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
}
/*
@ -11202,6 +11275,8 @@ static int ssl_write_real( mbedtls_ssl_context *ssl,
{
int ret = mbedtls_ssl_get_max_out_record_payload( ssl );
const size_t max_len = (size_t) ret;
volatile const unsigned char *buf_dup = buf;
volatile size_t len_dup = len;
if( ret < 0 )
{
@ -11224,6 +11299,7 @@ static int ssl_write_real( mbedtls_ssl_context *ssl,
#if defined(MBEDTLS_SSL_PROTO_TLS)
{
len = max_len;
len_dup = len;
}
#endif
}
@ -11259,8 +11335,12 @@ static int ssl_write_real( mbedtls_ssl_context *ssl,
return( ret );
}
}
return( (int) len );
/* Secure against buffer substitution */
if( buf_dup == buf && len_dup == len )
{
return( (int) len );
}
return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
}
/*
@ -11309,6 +11389,8 @@ static int ssl_write_split( mbedtls_ssl_context *ssl,
int mbedtls_ssl_write( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len )
{
int ret;
volatile const unsigned char *buf_dup = buf;
volatile size_t len_dup = len;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write" ) );
@ -11340,7 +11422,12 @@ int mbedtls_ssl_write( mbedtls_ssl_context *ssl, const unsigned char *buf, size_
MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write" ) );
return( ret );
/* Secure against buffer substitution */
if( buf_dup == buf && len_dup == len )
{
return( ret );
}
return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
}
/*
@ -12924,6 +13011,11 @@ int mbedtls_ssl_get_key_exchange_md_tls1_2( mbedtls_ssl_context *ssl,
{
int ret = 0;
mbedtls_md_context_t ctx;
volatile unsigned char* hash_dup = hash;
volatile size_t *hashlen_dup = hashlen;
volatile unsigned char* data_dup = data;
volatile size_t data_len_dup = data_len;
mbedtls_md_handle_t md_info = mbedtls_md_info_from_type( md_alg );
*hashlen = mbedtls_md_get_size( md_info );
@ -12969,7 +13061,13 @@ exit:
mbedtls_ssl_pend_fatal_alert( ssl,
MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR );
return( ret );
/* Secure against buffer substitution */
if( hash_dup == hash && hashlen_dup == hashlen &&
data_dup == data && data_len_dup == data_len )
{
return( ret );
}
return( MBEDTLS_ERR_PLATFORM_FAULT_DETECTED );
}
#endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \
MBEDTLS_SSL_PROTO_TLS1_2 */