Fix CVE-2014-0221

Unnecessary recursion when receiving a DTLS hello request can be used to
crash a DTLS client. Fixed by handling DTLS hello request without recursion.

Thanks to Imre Rad (Search-Lab Ltd.) for discovering this issue.

diff --git a/ssl/d1_both.c b/ssl/d1_both.c
index da8d1b146951aa5aa41d39052c4540a65a3d68cb..f4fc5bc0abc420921157c7d609b5e641ec9cf74c 100644 (file)
--- a/ssl/d1_both.c
+++ b/ssl/d1_both.c
@@ -793,6 +793,7 @@ dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
        int i,al;
        struct hm_header_st msg_hdr;
 
+       redo:
        /* see if we have the required fragment already */
        if ((frag_len = dtls1_retrieve_buffered_fragment(s,max,ok)) || *ok)
                {
@@ -851,8 +852,7 @@ dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
                                        s->msg_callback_arg);
                        
                        s->init_num = 0;
-                       return dtls1_get_message_fragment(s, st1, stn,
-                               max, ok);
+                       goto redo;
                        }
                else /* Incorrectly formated Hello request */
                        {