sched: Fix information leak in sys_sched_getattr()
authorVegard Nossum <vegard.nossum@oracle.com>
Sun, 16 Feb 2014 21:24:17 +0000 (22:24 +0100)
committerThomas Gleixner <tglx@linutronix.de>
Fri, 21 Feb 2014 20:27:10 +0000 (21:27 +0100)
commit4efbc454ba68def5ef285b26ebfcfdb605b52755
tree96fd992414451a19797a38476afed61b352d3d4f
parent3cf1962cdbf6b3a9e3ef21116d215bbab350ea37
sched: Fix information leak in sys_sched_getattr()

We're copying the on-stack structure to userspace, but forgot to give
the right number of bytes to copy. This allows the calling process to
obtain up to PAGE_SIZE bytes from the stack (and possibly adjacent
kernel memory).

This fix copies only as much as we actually have on the stack
(attr->size defaults to the size of the struct) and leaves the rest of
the userspace-provided buffer untouched.

Found using kmemcheck + trinity.

Fixes: d50dde5a10f30 ("sched: Add new scheduler syscalls to support an extended scheduling parameters ABI")
Cc: Dario Faggioli <raistlin@linux.it>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1392585857-10725-1-git-send-email-vegard.nossum@oracle.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
kernel/sched/core.c