[ovs-git] [openvswitch/ovs] b0a406: odp-util: Fix netlink message overflow with userdata.

[Ilya Maximets]

  Branch: refs/heads/branch-2.12
  Home:   https://github.com/openvswitch/ovs
  Commit: b0a40657485739090bfa9e9451378e895d582838
      https://github.com/openvswitch/ovs/commit/b0a40657485739090bfa9e9451378e895d582838
  Author: Ilya Maximets <i.maximets at ovn.org>
  Date:   2020-12-22 (Tue, 22 Dec 2020)

  Changed paths:
    M lib/odp-util.c
    M lib/odp-util.h
    M ofproto/ofproto-dpif-upcall.c
    M ofproto/ofproto-dpif-xlate.c
    M tests/odp.at

  Log Message:
  -----------
  odp-util: Fix netlink message overflow with userdata.

Too big userdata could overflow netlink message leading to out-of-bound
memory accesses or assertion while formatting nested actions.

Fix that by checking the size and returning correct error code.

Credit to OSS-Fuzz.

Reported-at: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=27640
Fixes: e995e3df57ea ("Allow OVS_USERSPACE_ATTR_USERDATA to be variable length.")
Signed-off-by: Ilya Maximets <i.maximets at ovn.org>
Acked-by: Flavio Leitner <fbl at sysclose.org>