On Mon, Mar 2, 2015 at 9:20 AM, Jeff Vander Stoep <jeffv@xxxxxxxxxx> wrote:
> A userspace call to mmap(MAP_LOCKED) may result in the successful
> locking of memory while also producing a confusing audit log denial.
> can_do_mlock checks capable and rlimit. If either of these return
> positive can_do_mlock returns true. The capable check leads to an LSM
> hook used by apparmour and selinux which produce the audit denial.
> Reordering so rlimit is checked first eliminates the denial on success,
> only recording a denial when the lock is unsuccessful as a result of
> the denial.
>
Acked-By: Nick Kralevich <nnk@xxxxxxxxxx>
> Signed-off-by: Jeff Vander Stoep <jeffv@xxxxxxxxxx>
> ---
> mm/mlock.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/mlock.c b/mm/mlock.c
> index 73cf098..8a54cd2 100644
> --- a/mm/mlock.c
> +++ b/mm/mlock.c
> @@ -26,10 +26,10 @@
>
> int can_do_mlock(void)
> {
> - if (capable(CAP_IPC_LOCK))
> - return 1;
> if (rlimit(RLIMIT_MEMLOCK) != 0)
> return 1;
> + if (capable(CAP_IPC_LOCK))
> + return 1;
> return 0;
> }
> EXPORT_SYMBOL(can_do_mlock);
> --
> 2.2.0.rc0.207.ga3a616c
>
--
Nick Kralevich | Android Security | nnk@xxxxxxxxxx | 650.214.4037
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