Revision 73223e4e2e3867ebf033a5a8eb2e5df0158ccc99 authored by zhong jiang on 18 August 2017, 22:16:24 UTC, committed by Linus Torvalds on 18 August 2017, 22:32:02 UTC
I hit a use after free issue when executing trinity and repoduced it
with KASAN enabled. The related call trace is as follows.
BUG: KASan: use after free in SyS_get_mempolicy+0x3c8/0x960 at addr ffff8801f582d766
Read of size 2 by task syz-executor1/798
INFO: Allocated in mpol_new.part.2+0x74/0x160 age=3 cpu=1 pid=799
__slab_alloc+0x768/0x970
kmem_cache_alloc+0x2e7/0x450
mpol_new.part.2+0x74/0x160
mpol_new+0x66/0x80
SyS_mbind+0x267/0x9f0
system_call_fastpath+0x16/0x1b
INFO: Freed in __mpol_put+0x2b/0x40 age=4 cpu=1 pid=799
__slab_free+0x495/0x8e0
kmem_cache_free+0x2f3/0x4c0
__mpol_put+0x2b/0x40
SyS_mbind+0x383/0x9f0
system_call_fastpath+0x16/0x1b
INFO: Slab 0xffffea0009cb8dc0 objects=23 used=8 fp=0xffff8801f582de40 flags=0x200000000004080
INFO: Object 0xffff8801f582d760 @offset=5984 fp=0xffff8801f582d600
Bytes b4 ffff8801f582d750: ae 01 ff ff 00 00 00 00 5a 5a 5a 5a 5a 5a 5a 5a ........ZZZZZZZZ
Object ffff8801f582d760: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ffff8801f582d770: 6b 6b 6b 6b 6b 6b 6b a5 kkkkkkk.
Redzone ffff8801f582d778: bb bb bb bb bb bb bb bb ........
Padding ffff8801f582d8b8: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ
Memory state around the buggy address:
ffff8801f582d600: fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8801f582d680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8801f582d700: fc fc fc fc fc fc fc fc fc fc fc fc fb fb fb fc
!shared memory policy is not protected against parallel removal by other
thread which is normally protected by the mmap_sem. do_get_mempolicy,
however, drops the lock midway while we can still access it later.
Early premature up_read is a historical artifact from times when
put_user was called in this path see https://lwn.net/Articles/124754/
but that is gone since 8bccd85ffbaf ("[PATCH] Implement sys_* do_*
layering in the memory policy layer."). but when we have the the
current mempolicy ref count model. The issue was introduced
accordingly.
Fix the issue by removing the premature release.
Link: http://lkml.kernel.org/r/1502950924-27521-1-git-send-email-zhongjiang@huawei.com
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org> [2.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent da094e4
sgi-ioc4.txt
====================================
SGI IOC4 PCI (multi function) device
====================================
The SGI IOC4 PCI device is a bit of a strange beast, so some notes on
it are in order.
First, even though the IOC4 performs multiple functions, such as an
IDE controller, a serial controller, a PS/2 keyboard/mouse controller,
and an external interrupt mechanism, it's not implemented as a
multifunction device. The consequence of this from a software
standpoint is that all these functions share a single IRQ, and
they can't all register to own the same PCI device ID. To make
matters a bit worse, some of the register blocks (and even registers
themselves) present in IOC4 are mixed-purpose between these several
functions, meaning that there's no clear "owning" device driver.
The solution is to organize the IOC4 driver into several independent
drivers, "ioc4", "sgiioc4", and "ioc4_serial". Note that there is no
PS/2 controller driver as this functionality has never been wired up
on a shipping IO card.
ioc4
====
This is the core (or shim) driver for IOC4. It is responsible for
initializing the basic functionality of the chip, and allocating
the PCI resources that are shared between the IOC4 functions.
This driver also provides registration functions that the other
IOC4 drivers can call to make their presence known. Each driver
needs to provide a probe and remove function, which are invoked
by the core driver at appropriate times. The interface of these
IOC4 function probe and remove operations isn't precisely the same
as PCI device probe and remove operations, but is logically the
same operation.
sgiioc4
=======
This is the IDE driver for IOC4. Its name isn't very descriptive
simply for historical reasons (it used to be the only IOC4 driver
component). There's not much to say about it other than it hooks
up to the ioc4 driver via the appropriate registration, probe, and
remove functions.
ioc4_serial
===========
This is the serial driver for IOC4. There's not much to say about it
other than it hooks up to the ioc4 driver via the appropriate registration,
probe, and remove functions.
Computing file changes ...
