Avoid double free when processing DTLS packets.

The |item| variable, in both of these cases, may contain a pointer to a
|pitem| structure within |s->d1->buffered_messages|. It was being freed
in the error case while still being in |buffered_messages|. When the
error later caused the |SSL*| to be destroyed, the item would be double
freed.

Thanks to Wah-Teh Chang for spotting that the fix in 1632ef74 was
inconsistent with the other error paths (but correct).

Fixes CVE-2014-3505

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Emilia Käsper <emilia@openssl.org>

diff --git a/ssl/d1_both.c b/ssl/d1_both.c
index 51d484d7eaad599870b9146c5e17cdd1a5053821..b720a54311b4858b3c62991c9bf7e3e172b164fc 100644 (file)
--- a/ssl/d1_both.c
+++ b/ssl/d1_both.c
@@ -698,8 +698,7 @@ dtls1_reassemble_fragment(SSL *s, struct hm_header_st* msg_hdr, int *ok)
        return DTLS1_HM_FRAGMENT_RETRY;
 
 err:
-       if (frag != NULL) dtls1_hm_fragment_free(frag);
-       if (item != NULL) OPENSSL_free(item);
+       if (frag != NULL && item == NULL) dtls1_hm_fragment_free(frag);
        *ok = 0;
        return i;
        }
@@ -783,8 +782,7 @@ dtls1_process_out_of_seq_message(SSL *s, struct hm_header_st* msg_hdr, int *ok)
        return DTLS1_HM_FRAGMENT_RETRY;
 
 err:
-       if ( frag != NULL) dtls1_hm_fragment_free(frag);
-       if ( item != NULL) OPENSSL_free(item);
+       if (frag != NULL && item == NULL) dtls1_hm_fragment_free(frag);
        *ok = 0;
        return i;
        }