[lwip-devel] [bug #60455] Crash in ip6_output with debugging enabled.

[Eric Koldeweij]

URL:
  <https://savannah.nongnu.org/bugs/?60455>

                 Summary: Crash in ip6_output with debugging enabled.
                 Project: lwIP - A Lightweight TCP/IP stack
            Submitted by: eric_koldeweij
            Submitted on: Mon 26 Apr 2021 08:28:36 AM UTC
                Category: IPv6
                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

    _______________________________________________________

Details:

When attempting to debug an lwip setup a crash was seen in ip6_output.

It turns out the crash only occurs if LWIP_DEBUG is enabled. If the parameter
dest is NULL the function tries to find a route using the destination address
of the packet instead. If this fails as well a debug message is printed but it
is still using dest causing a NULL pointer dereference and crash at
src/core/ipv6/ip6.c line 1312.

If dest is NULL and finding a proper interface still fails, the debug print
should use dest_addr instead of dest for its debug print.

A simple oneliner can fix this. Please see attached patch.



    _______________________________________________________

File Attachments:


-------------------------------------------------------
Date: Mon 26 Apr 2021 08:28:36 AM UTC  Name: patch.txt  Size: 449B   By:
eric_koldeweij

<http://savannah.nongnu.org/bugs/download.php?file_id=51321>

    _______________________________________________________

Reply to this item at:

  <https://savannah.nongnu.org/bugs/?60455>

_______________________________________________
  Message sent via Savannah
  https://savannah.nongnu.org/