Merge remote-tracking branch 'upstream-restricted/pr/427' into mbedtls-2.1-restricted
diff --git a/ChangeLog b/ChangeLog
index 6d1ec36..36696e6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -32,6 +32,12 @@
Reported by Marco Macchetti, Kudelski Group.
* Wipe stack buffer temporarily holding EC private exponent
after keypair generation.
+ * Fix heap corruption in implementation of truncated HMAC extension.
+ When the truncated HMAC extension is enabled and CBC is used,
+ sending a malicious application packet can be used to selectively
+ corrupt 6 bytes on the peer's heap, potentially leading to crash or
+ remote code execution. This can be triggered remotely from either
+ side in both TLS and DTLS.
Bugfix
* Fix some invalid RSA-PSS signatures with keys of size 8N+1 that were
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 7ceee4d..16b4d48 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -1284,14 +1284,17 @@
defined(MBEDTLS_SSL_PROTO_TLS1_2)
if( ssl->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_1 )
{
+ unsigned char mac[MBEDTLS_SSL_MAC_ADD];
+
mbedtls_md_hmac_update( &ssl->transform_out->md_ctx_enc, ssl->out_ctr, 8 );
mbedtls_md_hmac_update( &ssl->transform_out->md_ctx_enc, ssl->out_hdr, 3 );
mbedtls_md_hmac_update( &ssl->transform_out->md_ctx_enc, ssl->out_len, 2 );
mbedtls_md_hmac_update( &ssl->transform_out->md_ctx_enc,
ssl->out_msg, ssl->out_msglen );
- mbedtls_md_hmac_finish( &ssl->transform_out->md_ctx_enc,
- ssl->out_msg + ssl->out_msglen );
+ mbedtls_md_hmac_finish( &ssl->transform_out->md_ctx_enc, mac );
mbedtls_md_hmac_reset( &ssl->transform_out->md_ctx_enc );
+
+ memcpy( ssl->out_msg + ssl->out_msglen, mac, ssl->transform_out->maclen );
}
else
#endif
@@ -1553,8 +1556,6 @@
return( 0 );
}
-#define SSL_MAX_MAC_SIZE 48
-
static int ssl_decrypt_buf( mbedtls_ssl_context *ssl )
{
size_t i;
@@ -1722,7 +1723,7 @@
#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
if( ssl->session_in->encrypt_then_mac == MBEDTLS_SSL_ETM_ENABLED )
{
- unsigned char computed_mac[SSL_MAX_MAC_SIZE];
+ unsigned char mac_expect[MBEDTLS_SSL_MAC_ADD];
unsigned char pseudo_hdr[13];
MBEDTLS_SSL_DEBUG_MSG( 3, ( "using encrypt then mac" ) );
@@ -1740,16 +1741,16 @@
mbedtls_md_hmac_update( &ssl->transform_in->md_ctx_dec, pseudo_hdr, 13 );
mbedtls_md_hmac_update( &ssl->transform_in->md_ctx_dec,
ssl->in_iv, ssl->in_msglen );
- mbedtls_md_hmac_finish( &ssl->transform_in->md_ctx_dec, computed_mac );
+ mbedtls_md_hmac_finish( &ssl->transform_in->md_ctx_dec, mac_expect );
mbedtls_md_hmac_reset( &ssl->transform_in->md_ctx_dec );
MBEDTLS_SSL_DEBUG_BUF( 4, "message mac", ssl->in_iv + ssl->in_msglen,
ssl->transform_in->maclen );
- MBEDTLS_SSL_DEBUG_BUF( 4, "computed mac", computed_mac,
+ MBEDTLS_SSL_DEBUG_BUF( 4, "expected mac", mac_expect,
ssl->transform_in->maclen );
- if( mbedtls_ssl_safer_memcmp( ssl->in_iv + ssl->in_msglen, computed_mac,
- ssl->transform_in->maclen ) != 0 )
+ if( mbedtls_ssl_safer_memcmp( ssl->in_iv + ssl->in_msglen, mac_expect,
+ ssl->transform_in->maclen ) != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "message mac does not match" ) );
@@ -1909,15 +1910,13 @@
#if defined(SSL_SOME_MODES_USE_MAC)
if( auth_done == 0 )
{
- unsigned char tmp[SSL_MAX_MAC_SIZE];
+ unsigned char mac_expect[MBEDTLS_SSL_MAC_ADD];
ssl->in_msglen -= ssl->transform_in->maclen;
ssl->in_len[0] = (unsigned char)( ssl->in_msglen >> 8 );
ssl->in_len[1] = (unsigned char)( ssl->in_msglen );
- memcpy( tmp, ssl->in_msg + ssl->in_msglen, ssl->transform_in->maclen );
-
#if defined(MBEDTLS_SSL_PROTO_SSL3)
if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
{
@@ -1956,8 +1955,7 @@
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 );
- mbedtls_md_hmac_finish( &ssl->transform_in->md_ctx_dec,
- ssl->in_msg + ssl->in_msglen );
+ mbedtls_md_hmac_finish( &ssl->transform_in->md_ctx_dec, mac_expect );
/* Call mbedtls_md_process at least once due to cache attacks */
for( j = 0; j < extra_run + 1; j++ )
mbedtls_md_process( &ssl->transform_in->md_ctx_dec, ssl->in_msg );
@@ -1972,12 +1970,12 @@
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
- MBEDTLS_SSL_DEBUG_BUF( 4, "message mac", tmp, ssl->transform_in->maclen );
- MBEDTLS_SSL_DEBUG_BUF( 4, "computed mac", ssl->in_msg + ssl->in_msglen,
- ssl->transform_in->maclen );
+ 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 );
- if( mbedtls_ssl_safer_memcmp( tmp, ssl->in_msg + ssl->in_msglen,
- ssl->transform_in->maclen ) != 0 )
+ if( mbedtls_ssl_safer_memcmp( ssl->in_msg + ssl->in_msglen, mac_expect,
+ ssl->transform_in->maclen ) != 0 )
{
#if defined(MBEDTLS_SSL_DEBUG_ALL)
MBEDTLS_SSL_DEBUG_MSG( 1, ( "message mac does not match" ) );
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index ff1ab85..bdbe55f 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -699,40 +699,40 @@
"$P_SRV debug_level=4" \
"$P_CLI force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA" \
0 \
- -s "dumping 'computed mac' (20 bytes)" \
- -S "dumping 'computed mac' (10 bytes)"
+ -s "dumping 'expected mac' (20 bytes)" \
+ -S "dumping 'expected mac' (10 bytes)"
run_test "Truncated HMAC: client disabled, server default" \
"$P_SRV debug_level=4" \
"$P_CLI force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA \
trunc_hmac=0" \
0 \
- -s "dumping 'computed mac' (20 bytes)" \
- -S "dumping 'computed mac' (10 bytes)"
+ -s "dumping 'expected mac' (20 bytes)" \
+ -S "dumping 'expected mac' (10 bytes)"
run_test "Truncated HMAC: client enabled, server default" \
"$P_SRV debug_level=4" \
"$P_CLI force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA \
trunc_hmac=1" \
0 \
- -s "dumping 'computed mac' (20 bytes)" \
- -S "dumping 'computed mac' (10 bytes)"
+ -s "dumping 'expected mac' (20 bytes)" \
+ -S "dumping 'expected mac' (10 bytes)"
run_test "Truncated HMAC: client enabled, server disabled" \
"$P_SRV debug_level=4 trunc_hmac=0" \
"$P_CLI force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA \
trunc_hmac=1" \
0 \
- -s "dumping 'computed mac' (20 bytes)" \
- -S "dumping 'computed mac' (10 bytes)"
+ -s "dumping 'expected mac' (20 bytes)" \
+ -S "dumping 'expected mac' (10 bytes)"
run_test "Truncated HMAC: client enabled, server enabled" \
"$P_SRV debug_level=4 trunc_hmac=1" \
"$P_CLI force_ciphersuite=TLS-RSA-WITH-AES-128-CBC-SHA \
trunc_hmac=1" \
0 \
- -S "dumping 'computed mac' (20 bytes)" \
- -s "dumping 'computed mac' (10 bytes)"
+ -S "dumping 'expected mac' (20 bytes)" \
+ -s "dumping 'expected mac' (10 bytes)"
# Tests for Encrypt-then-MAC extension