chan_sip: Don't crash in Dial on invalid destination

Stripping the DNID in a SIP dial string can result in attempting to call
the argument parsing macros on an empty string, causing a crash.

ASTERISK-26131 #close
Reported by: Dwayne Hubbard
Patches:
	dw-asterisk-master-dnid-crash.patch (license #6257) patch
	uploaded by Dwayne Hubbard

Change-Id: Ib84c1f740a9ec0539d582b09d847fc85ddca1c5e

diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index b8cc7bf76518b6c77a657d28090c45ed8e55cdf2..b1a8de5f2560b2c95f6c655e76e6620e8ab851de 100644 (file)
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -30465,6 +30465,17 @@ static struct ast_channel *sip_request_call(const char *type, struct ast_format_
                ast_string_field_set(p, todnid, dnid);
        }
 
+       /* If stripping the DNID left us with nothing, bail out */
+       if (ast_strlen_zero(tmp)) {
+               dialog_unlink_all(p);
+               dialog_unref(p, "unref dialog p from bad destination");
+               *cause = AST_CAUSE_DESTINATION_OUT_OF_ORDER;
+               if (callid) {
+                       ast_callid_unref(callid);
+               }
+               return NULL;
+       }
+
        /* Divvy up the items separated by slashes */
        AST_NONSTANDARD_APP_ARGS(args, tmp, '/');