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.
(cherry picked from commit d3152655d5319ce883c8e3ac4b99f8de4c59d846)

diff --git a/ssl/d1_both.c b/ssl/d1_both.c
index 2c06fc28f75206cf786c9b8351392ccd901cb496..820c8f08fa90365faf89e29964c1846ce2cbbee1 100644 (file)
--- a/ssl/d1_both.c
+++ b/ssl/d1_both.c
@@ -789,6 +789,7 @@ 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)
                {
@@ -847,8 +848,7 @@ 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 */
                        {