[PATCH 3.8 106/116] x86_32, entry: Do syscall exit work on badsys (CVE-2014-4508)

[Andy Lutomirski]

On Tue, Jul 22, 2014 at 3:21 PM, Kamal Mostafa <kamal at canonical.com> wrote:
> 3.8.13.27 -stable review patch.  If anyone has any objections, please let me know.
>
> ------------------
>
> From: Andy Lutomirski <luto at amacapital.net>
>
> commit 554086d85e71f30abe46fc014fea31929a7c6a8a upstream.
>
> The bad syscall nr paths are their own incomprehensible route
> through the entry control flow.  Rearrange them to work just like
> syscalls that return -ENOSYS.
>
> This fixes an OOPS in the audit code when fast-path auditing is
> enabled and sysenter gets a bad syscall nr (CVE-2014-4508).
>
> This has probably been broken since Linux 2.6.27:
> af0575bba0 i386 syscall audit fast-path

Don't apply this without:

https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git/commit/?h=x86/urgent&id=8142b215501f8b291a108a202b3a053a265b03dd

Sorry!

--Andy