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[Steve Beattie <sbeattie@xxxxxxxxxx>]

** Tags added: kernel-cve-skip-description

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https://bugs.launchpad.net/bugs/1555353

Title:
  integer overflow in xt_alloc_table_info

Status in linux package in Ubuntu:
  Fix Committed
Status in linux source package in Wily:
  Fix Committed
Status in linux source package in Xenial:
  Fix Committed

Bug description:
  [Impact]
  [From https://code.google.com/p/google-security-research/issues/detail?id=758 ]

  A recent refactoring cof this codepath
  (https://github.com/torvalds/linux/commit/2e4e6a17af35be359cc8f1c924f8f198fbd478cc)
  introduced an integer overflow in xt_alloc_table_info, which on 32-bit
  systems can lead to small structure allocation and a copy_from_user
  based heap corruption.

  More specifically, the overflow may have been introduced in
  https://github.com/torvalds/linux/commit/711bdde6a884354ddae8da2fcb495b2a9364cc90
  ; specifically the bit:

    +       size_t sz = sizeof(*info) + size;

  (where size is an unsigned int passed from userspace).

  This issue should only affect 32bit platforms (xt_table_info.size is
  an unsigned int).

  [Fix]
  Upstream proposed fix: http://marc.info/?l=netfilter-devel&m=145757136822750&w=2

  [Test Case]
  Download v4 code from: https://code.google.com/p/google-security-research/issues/detail?id=758
  gcc *v4.c -o v4
  ./v4
  Your machine should _not_ crash. This only affects 32-bit kernels

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