Cache ClientHello extension

This extension is quite costly to generate, and we don't want to re-do it
again when the server performs a DTLS HelloVerify. So, cache the result the
first time and re-use if/when we build a new ClientHello.

Note: re-send due to timeouts are different, as the whole message is cached
already, so they don't need any special support.
This commit is contained in:
Manuel Pégourié-Gonnard 2015-09-17 14:16:30 +02:00
parent 77c0646ef2
commit d0d8cb36a4
2 changed files with 57 additions and 5 deletions

View File

@ -307,12 +307,47 @@ static void ssl_write_ecjpake_kkpp_ext( mbedtls_ssl_context *ssl,
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ECJPAKE_KKPP >> 8 ) & 0xFF );
*p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_ECJPAKE_KKPP ) & 0xFF );
if( ( ret = mbedtls_ecjpake_write_round_one( &ssl->handshake->ecjpake_ctx,
p + 2, end - p - 2, &kkpp_len,
ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
/*
* We may need to send ClientHello multiple times for Hello verification.
* We don't want to compute fresh values every time (both for performance
* and consistency reasons), so cache the extension content.
*/
if( ssl->handshake->ecjpake_cache == NULL ||
ssl->handshake->ecjpake_cache_len == 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1 , "mbedtls_ecjpake_write_round_one", ret );
return;
MBEDTLS_SSL_DEBUG_MSG( 3, ( "generating new ecjpake parameters" ) );
if( ( ret = mbedtls_ecjpake_write_round_one( &ssl->handshake->ecjpake_ctx,
p + 2, end - p - 2, &kkpp_len,
ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1 , "mbedtls_ecjpake_write_round_one", ret );
return;
}
ssl->handshake->ecjpake_cache = mbedtls_calloc( 1, kkpp_len );
if( ssl->handshake->ecjpake_cache == NULL )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "allocation failed" ) );
return;
}
memcpy( ssl->handshake->ecjpake_cache, p + 2, kkpp_len );
ssl->handshake->ecjpake_cache_len = kkpp_len;
}
else
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "re-using cached ecjpake parameters" ) );
kkpp_len = ssl->handshake->ecjpake_cache_len;
if( (size_t)( end - p - 2 ) < kkpp_len )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
return;
}
memcpy( p + 2, ssl->handshake->ecjpake_cache, kkpp_len );
}
*p++ = (unsigned char)( ( kkpp_len >> 8 ) & 0xFF );
@ -1090,6 +1125,11 @@ static int ssl_parse_ecjpake_kkpp( mbedtls_ssl_context *ssl,
return( 0 );
}
/* If we got here, we no longer need our cached extension */
mbedtls_free( ssl->handshake->ecjpake_cache );
ssl->handshake->ecjpake_cache = NULL;
ssl->handshake->ecjpake_cache_len = 0;
if( ( ret = mbedtls_ecjpake_read_round_one( &ssl->handshake->ecjpake_ctx,
buf, len ) ) != 0 )
{

View File

@ -2535,6 +2535,7 @@ run_test "ECJPAKE: working, TLS" \
0 \
-c "add ciphersuite: c0ff" \
-c "adding ecjpake_kkpp extension" \
-C "re-using cached ecjpake parameters" \
-s "found ecjpake kkpp extension" \
-S "skip ecjpake kkpp extension" \
-S "ciphersuite mismatch: ecjpake not configured" \
@ -2548,6 +2549,7 @@ run_test "ECJPAKE: password mismatch, TLS" \
"$P_CLI debug_level=3 ecjpake_pw=bad \
force_ciphersuite=TLS-ECJPAKE-WITH-AES-128-CCM-8" \
1 \
-C "re-using cached ecjpake parameters" \
-s "SSL - Verification of the message MAC failed"
run_test "ECJPAKE: working, DTLS" \
@ -2555,6 +2557,15 @@ run_test "ECJPAKE: working, DTLS" \
"$P_CLI debug_level=3 dtls=1 ecjpake_pw=bla \
force_ciphersuite=TLS-ECJPAKE-WITH-AES-128-CCM-8" \
0 \
-c "re-using cached ecjpake parameters" \
-S "SSL - Verification of the message MAC failed"
run_test "ECJPAKE: working, DTLS, no cookie" \
"$P_SRV debug_level=3 dtls=1 ecjpake_pw=bla cookies=0" \
"$P_CLI debug_level=3 dtls=1 ecjpake_pw=bla \
force_ciphersuite=TLS-ECJPAKE-WITH-AES-128-CCM-8" \
0 \
-C "re-using cached ecjpake parameters" \
-S "SSL - Verification of the message MAC failed"
run_test "ECJPAKE: password mismatch, DTLS" \
@ -2562,6 +2573,7 @@ run_test "ECJPAKE: password mismatch, DTLS" \
"$P_CLI debug_level=3 dtls=1 ecjpake_pw=bad \
force_ciphersuite=TLS-ECJPAKE-WITH-AES-128-CCM-8" \
1 \
-c "re-using cached ecjpake parameters" \
-s "SSL - Verification of the message MAC failed"
# Tests for ciphersuites per version