[lwip-devel] [bug #49648] Always check whether netif_default is NULL

[David van Moolenbroek]

URL:
  <http://savannah.nongnu.org/bugs/?49648>

                 Summary: Always check whether netif_default is NULL
                 Project: lwIP - A Lightweight TCP/IP stack
            Submitted by: dcvmoole
            Submitted on: Fri 18 Nov 2016 10:43:13 PM GMT
                Category: None
                Severity: 3 - Normal
              Item Group: Crash Error
                  Status: None
                 Privacy: Public
             Assigned to: None
             Open/Closed: Open
         Discussion Lock: Any
         Planned Release: None
            lwIP version: git head

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Details:

There may be cases where there is no default interface, for example when a
real interface has not (yet) been configured. I ran into a crash while
attempting to route a link-local address on a loopback device in that
situation. Attached patch should resolve that.

(I'm not sure whether to file these things as bugs or patches by the way..)

===

In general, netif_default may be NULL, and various places in the code already
check for this case before attempting to dereference the netif_default
pointer.  Some places do not perform this check though, and may cause null
pointer dereferences if netif_default is not set. This patch adds NULL checks
to those places as well.



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File Attachments:


-------------------------------------------------------
Date: Fri 18 Nov 2016 10:43:13 PM GMT  Name:
0001-Always-check-whether-netif_default-is-NULL.patch  Size: 3kB   By:
dcvmoole

<http://savannah.nongnu.org/bugs/download.php?file_id=39014>

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