More SSL debug messages for ClientHello parsing
In particular, be verbose when checking the ClientHello cookie in a possible
DTLS reconnection.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/library/ssl_msg.c b/library/ssl_msg.c
index 083c8d2..a77a1a8 100644
--- a/library/ssl_msg.c
+++ b/library/ssl_msg.c
@@ -3139,8 +3139,8 @@
#if defined(MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE) && defined(MBEDTLS_SSL_SRV_C)
/*
- * Without any SSL context, check if a datagram looks like a ClientHello with
- * a valid cookie, and if it doesn't, generate a HelloVerifyRequest message.
+ * Check if a datagram looks like a ClientHello with a valid cookie,
+ * and if it doesn't, generate a HelloVerifyRequest message.
* Both input and output include full DTLS headers.
*
* - if cookie is valid, return 0
@@ -3150,9 +3150,7 @@
* - otherwise return a specific error code
*/
static int ssl_check_dtls_clihlo_cookie(
- mbedtls_ssl_cookie_write_t *f_cookie_write,
- mbedtls_ssl_cookie_check_t *f_cookie_check,
- void *p_cookie,
+ mbedtls_ssl_context *ssl,
const unsigned char *cli_id, size_t cli_id_len,
const unsigned char *in, size_t in_len,
unsigned char *obuf, size_t buf_len, size_t *olen )
@@ -3186,26 +3184,52 @@
*
* Minimum length is 61 bytes.
*/
- if( in_len < 61 ||
- in[0] != MBEDTLS_SSL_MSG_HANDSHAKE ||
+ MBEDTLS_SSL_DEBUG_MSG( 4, ( "check cookie: in_len=%u",
+ (unsigned) in_len ) );
+ MBEDTLS_SSL_DEBUG_BUF( 4, "cli_id", cli_id, cli_id_len );
+ if( in_len < 61 )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 4, ( "check cookie: record too short" ) );
+ return( MBEDTLS_ERR_SSL_DECODE_ERROR );
+ }
+ if( in[0] != MBEDTLS_SSL_MSG_HANDSHAKE ||
in[3] != 0 || in[4] != 0 ||
in[19] != 0 || in[20] != 0 || in[21] != 0 )
{
+ MBEDTLS_SSL_DEBUG_MSG( 4, ( "check cookie: not a good ClientHello" ) );
+ MBEDTLS_SSL_DEBUG_MSG( 4, ( " type=%u epoch=%u fragment_offset=%u",
+ in[0],
+ (unsigned) in[3] << 8 | in[4],
+ (unsigned) in[19] << 16 | in[20] << 8 | in[21] ) );
return( MBEDTLS_ERR_SSL_DECODE_ERROR );
}
sid_len = in[59];
if( sid_len > in_len - 61 )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 4, ( "check cookie: sid_len=%u > %u",
+ (unsigned) sid_len,
+ (unsigned) in_len - 61 ) );
return( MBEDTLS_ERR_SSL_DECODE_ERROR );
+ }
+ MBEDTLS_SSL_DEBUG_BUF( 4, "sid received from network",
+ in + 60, sid_len );
cookie_len = in[60 + sid_len];
- if( cookie_len > in_len - 60 )
+ if( cookie_len > in_len - 60 ) {
+ MBEDTLS_SSL_DEBUG_MSG( 4, ( "check cookie: cookie_len=%u > %u",
+ (unsigned) cookie_len,
+ (unsigned) in_len - 60 ) );
return( MBEDTLS_ERR_SSL_DECODE_ERROR );
+ }
- if( f_cookie_check( p_cookie, in + sid_len + 61, cookie_len,
- cli_id, cli_id_len ) == 0 )
+ MBEDTLS_SSL_DEBUG_BUF( 4, "cookie received from network",
+ in + sid_len + 61, cookie_len );
+ if( ssl->conf->f_cookie_check( ssl->conf->p_cookie,
+ in + sid_len + 61, cookie_len,
+ cli_id, cli_id_len ) == 0 )
{
- /* Valid cookie */
+ MBEDTLS_SSL_DEBUG_MSG( 4, ( "check cookie: valid" ) );
return( 0 );
}
@@ -3240,8 +3264,9 @@
/* Generate and write actual cookie */
p = obuf + 28;
- if( f_cookie_write( p_cookie,
- &p, obuf + buf_len, cli_id, cli_id_len ) != 0 )
+ if( ssl->conf->f_cookie_write( ssl->conf->p_cookie,
+ &p, obuf + buf_len,
+ cli_id, cli_id_len ) != 0 )
{
return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
}
@@ -3296,9 +3321,7 @@
}
ret = ssl_check_dtls_clihlo_cookie(
- ssl->conf->f_cookie_write,
- ssl->conf->f_cookie_check,
- ssl->conf->p_cookie,
+ ssl,
ssl->cli_id, ssl->cli_id_len,
ssl->in_buf, ssl->in_left,
ssl->out_buf, MBEDTLS_SSL_OUT_CONTENT_LEN, &len );
@@ -3481,7 +3504,6 @@
/*
* Parse and validate record version
*/
-
rec->ver[0] = buf[ rec_hdr_version_offset + 0 ];
rec->ver[1] = buf[ rec_hdr_version_offset + 1 ];
tls_version = mbedtls_ssl_read_version( buf + rec_hdr_version_offset,
@@ -3489,10 +3511,12 @@
if( tls_version > ssl->conf->max_tls_version )
{
- MBEDTLS_SSL_DEBUG_MSG( 1, ( "TLS version mismatch" ) );
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "TLS version mismatch: got %u, expected max %u",
+ (unsigned) tls_version,
+ (unsigned) ssl->conf->max_tls_version) );
+
return( MBEDTLS_ERR_SSL_INVALID_RECORD );
}
-
/*
* Parse/Copy record sequence number.
*/
diff --git a/library/ssl_tls12_server.c b/library/ssl_tls12_server.c
index a1505d1..58d6093 100644
--- a/library/ssl_tls12_server.c
+++ b/library/ssl_tls12_server.c
@@ -1286,7 +1286,10 @@
if( buf[1] != 0 ||
msg_len != mbedtls_ssl_hs_hdr_len( ssl ) + ( ( buf[2] << 8 ) | buf[3] ) )
{
- MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message: %u != %u + %u",
+ (unsigned) msg_len,
+ (unsigned) mbedtls_ssl_hs_hdr_len( ssl ),
+ (unsigned) ( buf[2] << 8 ) | buf[3] ) );
return( MBEDTLS_ERR_SSL_DECODE_ERROR );
}
@@ -1327,6 +1330,11 @@
* For now we don't support fragmentation, so make sure
* fragment_offset == 0 and fragment_length == length
*/
+ MBEDTLS_SSL_DEBUG_MSG(
+ 4, ( "fragment_offset=%u fragment_length=%u length=%u",
+ (unsigned) ( ssl->in_msg[6] << 16 | ssl->in_msg[7] << 8 | ssl->in_msg[8] ),
+ (unsigned) ( ssl->in_msg[9] << 16 | ssl->in_msg[10] << 8 | ssl->in_msg[11] ),
+ (unsigned) ( ssl->in_msg[1] << 16 | ssl->in_msg[2] << 8 | ssl->in_msg[3] ) ) );
if( ssl->in_msg[6] != 0 || ssl->in_msg[7] != 0 || ssl->in_msg[8] != 0 ||
memcmp( ssl->in_msg + 1, ssl->in_msg + 9, 3 ) != 0 )
{