Fix bug with client auth with DTLS

library/ssl_tls.c

@@ -3454,10 +3454,10 @@ int ssl_parse_certificate( ssl_context *ssl )
     if( ssl->endpoint  == SSL_IS_SERVER &&
         ssl->minor_ver != SSL_MINOR_VERSION_0 )
     {
-        if( ssl->in_hslen   == 7                    &&
+        if( ssl->in_hslen   == 3 + ssl_hs_hdr_len( ssl ) &&
             ssl->in_msgtype == SSL_MSG_HANDSHAKE    &&
             ssl->in_msg[0]  == SSL_HS_CERTIFICATE   &&
-            memcmp( ssl->in_msg + 4, "\0\0\0", 3 ) == 0 )
+            memcmp( ssl->in_msg + ssl_hs_hdr_len( ssl ), "\0\0\0", 3 ) == 0 )
         {
             SSL_DEBUG_MSG( 1, ( "TLSv1 client has no certificate" ) );
 

tests/ssl-opt.sh

@@ -2024,6 +2024,28 @@ run_test    "DTLS cookie: enabled, IPv6" \
             -c "received hello verify request" \
             -S "SSL - The requested feature is not available"
 
+# Tests for various cases of client authentication with DTLS
+# (focused on handshake flows and message parsing)
+
+run_test    "DTLS client auth: required" \
+            "$P_SRV dtls=1 auth_mode=required" \
+            "$P_CLI dtls=1" \
+            0 \
+            -s "Verifying peer X.509 certificate... ok"
+
+run_test    "DTLS client auth: optional, client has no cert" \
+            "$P_SRV dtls=1 auth_mode=optional" \
+            "$P_CLI dtls=1 crt_file=none key_file=none" \
+            0 \
+            -s "! no client certificate sent"
+
+run_test    "DTLS client auth: optional, client has no cert" \
+            "$P_SRV dtls=1 auth_mode=none" \
+            "$P_CLI dtls=1 crt_file=none key_file=none debug_level=2" \
+            0 \
+            -c "skip write certificate$" \
+            -s "! no client certificate sent"
+
 # Tests for receiving fragmented handshake messages with DTLS
 
 requires_gnutls