[lwip-devel] [bug #57374] Assertion "this needs a pbuf in one piece!" failed

[Hiromasa Ito]

URL:
  <https://savannah.nongnu.org/bugs/?57374>

                 Summary: Assertion "this needs a pbuf in one piece!" failed
                 Project: lwIP - A Lightweight TCP/IP stack
            Submitted by: vhertz
            Submitted on: Sat 07 Dec 2019 01:11:02 PM 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: Other

    _______________________________________________________

Details:

Hi, all.

This is one of the assertion failures I found by fuzzing (to lwIP
ver2.1.0.RC1).
The following LWIP_ASSERT() at lwip/src/core/ipv6/ip6_frag.c:784 fails.


LWIP_ASSERT("this needs a pbuf in one piece!", (p->len >= (IP6_HLEN)));


I think this assert is not always true.
If `p` is a pbuf chain, The only first pbuf has the IPv6 header.
If `p` has only IPv6 datagrams, it can have payloads that are less than
IP6_HLEN.

You can reproduce this failure with 'crashed_inputs/003' attached to the
following message of lwip-devel:
https://lists.nongnu.org/archive/html/lwip-devel/2019-12/msg00013.html




    _______________________________________________________

Reply to this item at:

  <https://savannah.nongnu.org/bugs/?57374>

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