On Fri, Aug 14, 2015 at 10:45:07AM -0700, Greg Kroah-Hartman wrote:
> 3.14-stable review patch.  If anyone has any objections, please let me know.
>

These 3 patches seem to be relevant to other stable trees as well.  I'm
queuing them for the 3.16 kernel.

Cheers,
--
Luís


> ------------------
> 
> From: Amanieu d'Antras <aman...@gmail.com>
> 
> commit 3ead7c52bdb0ab44f4bb1feed505a8323cc12ba7 upstream.
> 
> This function may copy the si_addr_lsb field to user mode when it hasn't
> been initialized, which can leak kernel stack data to user mode.
> 
> Just checking the value of si_code is insufficient because the same
> si_code value is shared between multiple signals.  This is solved by
> checking the value of si_signo in addition to si_code.
> 
> Signed-off-by: Amanieu d'Antras <aman...@gmail.com>
> Cc: Oleg Nesterov <o...@redhat.com>
> Cc: Ingo Molnar <mi...@kernel.org>
> Signed-off-by: Andrew Morton <a...@linux-foundation.org>
> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
> 
> ---
>  fs/signalfd.c |    5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> --- a/fs/signalfd.c
> +++ b/fs/signalfd.c
> @@ -121,8 +121,9 @@ static int signalfd_copyinfo(struct sign
>                * Other callers might not initialize the si_lsb field,
>                * so check explicitly for the right codes here.
>                */
> -             if (kinfo->si_code == BUS_MCEERR_AR ||
> -                 kinfo->si_code == BUS_MCEERR_AO)
> +             if (kinfo->si_signo == SIGBUS &&
> +                 (kinfo->si_code == BUS_MCEERR_AR ||
> +                  kinfo->si_code == BUS_MCEERR_AO))
>                       err |= __put_user((short) kinfo->si_addr_lsb,
>                                         &uinfo->ssi_addr_lsb);
>  #endif
> 
> 
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