Merge remote-tracking branch 'public/pr/1955' into development

ChangeLog

@@ -13,6 +13,11 @@ Bugfix
    * Replace printf with mbedtls_printf in aria. Found by TrinityTonic in #1908.
    * Fix potential use-after-free in mbedtls_ssl_get_max_frag_len()
      and mbedtls_ssl_get_record_expansion() after a session reset. Fixes #1941.
+   * Fix a bug that caused SSL/TLS clients to incorrectly abort the handshake
+     with TLS versions 1.1 and earlier when the server requested authentication
+     without providing a list of CAs. This was due to an overly strict bounds
+     check in parsing the CertificateRequest message,
+     introduced in Mbed TLS 2.12.0. Fixes #1954.
 
 Changes
    * Copy headers preserving timestamps when doing a "make install".

library/ssl_cli.c

@@ -2721,7 +2721,7 @@ static int ssl_parse_certificate_request( mbedtls_ssl_context *ssl )
      * therefore the buffer length at this point must be greater than that
      * regardless of the actual code path.
      */
-    if( ssl->in_hslen <= mbedtls_ssl_hs_hdr_len( ssl ) + 3 + n )
+    if( ssl->in_hslen <= mbedtls_ssl_hs_hdr_len( ssl ) + 2 + n )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
         mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,

tests/ssl-opt.sh

@@ -804,6 +804,22 @@ run_test    "RC4: both enabled" \
             -S "SSL - None of the common ciphersuites is usable" \
             -S "SSL - The server has no ciphersuites in common"
 
+# Test empty CA list in CertificateRequest in TLS 1.1 and earlier
+
+requires_gnutls
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_1
+run_test    "CertificateRequest with empty CA list, TLS 1.1 (GnuTLS server)" \
+            "$G_SRV"\
+            "$P_CLI force_version=tls1_1" \
+            0
+
+requires_gnutls
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1
+run_test    "CertificateRequest with empty CA list, TLS 1.0 (GnuTLS server)" \
+            "$G_SRV"\
+            "$P_CLI force_version=tls1" \
+            0
+
 # Tests for SHA-1 support
 
 requires_config_disabled MBEDTLS_TLS_DEFAULT_ALLOW_SHA1_IN_CERTIFICATES