Fix issue in handling legacy_compression_methods in ssl_tls13_parse_client_hello()
Signed-off-by: Waleed Elmelegy <waleed.elmelegy@arm.com>
diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index f5ef920..ca3ea53 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -1265,6 +1265,8 @@
mbedtls_ssl_handshake_params *handshake = ssl->handshake;
int hrr_required = 0;
int no_usable_share_for_key_agreement = 0;
+ unsigned char legacy_compression_methods_len;
+ unsigned char legacy_compression_methods;
#if defined(MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_SOME_PSK_ENABLED)
int got_psk = 0;
@@ -1362,6 +1364,13 @@
p += cipher_suites_len;
cipher_suites_end = p;
+ legacy_compression_methods_len = *p;
+ legacy_compression_methods = *(p+1);
+
+ if (legacy_compression_methods_len != 1 || legacy_compression_methods != 0) {
+ return SSL_CLIENT_HELLO_TLS1_2;
+ }
+
/*
* Search for the supported versions extension and parse it to determine
* if the client supports TLS 1.3.