Found a little problem with the sip request handling that could lead to a quick crash...

Attaching to a running asterisk with "telnet hostname 5060", I would input "something", then hit return three times, and asterisk crashes.

I traced it to handle_request_do(), which zeroes out the data (an ast_str ptr) if the string is too short.
Instead of freeing the struct and nulling the pointer, it now just resets it, because this
ast_str is expected by the calling routine to still be there after handle_request_do() returns.

This appears to fix the crash. I assume that it was introduced with ast_str's being adopted.  It's a subtle and easy-to-miss sort of problem.

I also found all the places where the req.data is freed, and made sure the ptr is Nulled out as well;
no good leaving bad ptrs laying around-- I didn't need to do this, but it seemed a good thing to do...

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@112874 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index bc2ba55..ff8abb6 100644 (file)
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -2252,8 +2252,11 @@ cleanup2:
        ser = ast_tcptls_session_instance_destroy(ser);
        if (reqcpy.data)
                ast_free(reqcpy.data);
-       if (req.data)
+       if (req.data) {
                ast_free(req.data);
+               req.data = NULL;
+       }
+       
 
        if (req.socket.lock) {
                ast_mutex_destroy(req.socket.lock);
@@ -18129,8 +18132,10 @@ static int sipsock_read(int *id, int fd, short events, void *ignore)
        req.socket.lock = NULL;
 
        handle_request_do(&req, &sin);
-       if (req.data)
+       if (req.data) {
                ast_free(req.data);
+               req.data = NULL;
+       }
 
        return 1;
 }
@@ -18159,8 +18164,7 @@ static int handle_request_do(struct sip_request *req, struct sockaddr_in *sin)
                ast_verbose("--- (%d headers %d lines)%s ---\n", req->headers, req->lines, (req->headers + req->lines == 0) ? " Nat keepalive" : "");
 
        if (req->headers < 2) { /* Must have at least two headers */
-               ast_free(req->data);
-               req->data = NULL;
+               ast_str_reset(req->data); /* nulling this out is NOT a good idea here. */
                return 1;
        }