From: Dmitry Vyukov <dvyukov@google.com>
To: zhong jiang <zhongjiang@huawei.com>
Cc: syzbot <syzbot+cbb52e396df3e565ab02@syzkaller.appspotmail.com>,
Michal Hocko <mhocko@kernel.org>,
Andrea Arcangeli <aarcange@redhat.com>,
cgroups@vger.kernel.org, Johannes Weiner <hannes@cmpxchg.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
David Rientjes <rientjes@google.com>,
Hugh Dickins <hughd@google.com>,
Matthew Wilcox <willy@infradead.org>,
Mel Gorman <mgorman@suse.de>, Vlastimil Babka <vbabka@suse.cz>
Subject: Re: KASAN: use-after-free Read in get_mem_cgroup_from_mm
Date: Mon, 4 Mar 2019 08:40:16 +0100 [thread overview]
Message-ID: <CACT4Y+Z+CH0UTdSz-w_woMPrBwg-GuobV1Su4qd9ReffTkyfVg@mail.gmail.com> (raw)
In-Reply-To: <5C7BFE94.6070500@huawei.com>
On Sun, Mar 3, 2019 at 5:19 PM zhong jiang <zhongjiang@huawei.com> wrote:
>
> Hi, guys
>
> I also hit the following issue. but it fails to reproduce the issue by the log.
>
> it seems to the case that we access the mm->owner and deference it will result in the UAF.
> But it should not be possible that we specify the incomplete process to be the mm->owner.
>
> Any thoughts?
FWIW syzbot was able to reproduce this with this reproducer.
This looks like a very subtle race (threaded reproducer that runs
repeatedly in multiple processes), so most likely we are looking for
something like few instructions inconsistency window.
> Thanks,
> zhong jiang
>
> On 2018/12/4 23:43, syzbot wrote:
> > syzbot has found a reproducer for the following crash on:
> >
> > HEAD commit: 0072a0c14d5b Merge tag 'media/v4.20-4' of git://git.kernel..
> > git tree: upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=11c885a3400000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=b9cc5a440391cbfd
> > dashboard link: https://syzkaller.appspot.com/bug?extid=cbb52e396df3e565ab02
> > compiler: gcc (GCC) 8.0.1 20180413 (experimental)
> > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12835e25400000
> > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=172fa5a3400000
> >
> > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> > Reported-by: syzbot+cbb52e396df3e565ab02@syzkaller.appspotmail.com
> >
> > cgroup: fork rejected by pids controller in /syz2
> > ==================================================================
> > BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:182 [inline]
> > BUG: KASAN: use-after-free in task_css include/linux/cgroup.h:477 [inline]
> > BUG: KASAN: use-after-free in mem_cgroup_from_task mm/memcontrol.c:815 [inline]
> > BUG: KASAN: use-after-free in get_mem_cgroup_from_mm.part.62+0x6d7/0x880 mm/memcontrol.c:844
> > Read of size 8 at addr ffff8881b72af310 by task syz-executor198/9332
> >
> > CPU: 0 PID: 9332 Comm: syz-executor198 Not tainted 4.20.0-rc5+ #142
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> > Call Trace:
> > __dump_stack lib/dump_stack.c:77 [inline]
> > dump_stack+0x244/0x39d lib/dump_stack.c:113
> > print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256
> > kasan_report_error mm/kasan/report.c:354 [inline]
> > kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412
> > __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
> > __read_once_size include/linux/compiler.h:182 [inline]
> > task_css include/linux/cgroup.h:477 [inline]
> > mem_cgroup_from_task mm/memcontrol.c:815 [inline]
> > get_mem_cgroup_from_mm.part.62+0x6d7/0x880 mm/memcontrol.c:844
> > get_mem_cgroup_from_mm mm/memcontrol.c:834 [inline]
> > mem_cgroup_try_charge+0x608/0xe20 mm/memcontrol.c:5888
> > mcopy_atomic_pte mm/userfaultfd.c:71 [inline]
> > mfill_atomic_pte mm/userfaultfd.c:418 [inline]
> > __mcopy_atomic mm/userfaultfd.c:559 [inline]
> > mcopy_atomic+0xb08/0x2c70 mm/userfaultfd.c:609
> > userfaultfd_copy fs/userfaultfd.c:1705 [inline]
> > userfaultfd_ioctl+0x29fb/0x5610 fs/userfaultfd.c:1851
> > vfs_ioctl fs/ioctl.c:46 [inline]
> > file_ioctl fs/ioctl.c:509 [inline]
> > do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696
> > ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713
> > __do_sys_ioctl fs/ioctl.c:720 [inline]
> > __se_sys_ioctl fs/ioctl.c:718 [inline]
> > __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
> > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
> > entry_SYSCALL_64_after_hwframe+0x49/0xbe
> > RIP: 0033:0x44c7e9
> > Code: 5d c5 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 2b c5 fb ff c3 66 2e 0f 1f 84 00 00 00 00
> > RSP: 002b:00007f906b69fdb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> > RAX: ffffffffffffffda RBX: 00000000006e4a08 RCX: 000000000044c7e9
> > RDX: 0000000020000100 RSI: 00000000c028aa03 RDI: 0000000000000004
> > RBP: 00000000006e4a00 R08: 0000000000000000 R09: 0000000000000000
> > R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006e4a0c
> > R13: 00007ffdfd47813f R14: 00007f906b6a09c0 R15: 000000000000002d
> >
> > Allocated by task 9325:
> > save_stack+0x43/0xd0 mm/kasan/kasan.c:448
> > set_track mm/kasan/kasan.c:460 [inline]
> > kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
> > kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
> > kmem_cache_alloc_node+0x144/0x730 mm/slab.c:3644
> > alloc_task_struct_node kernel/fork.c:158 [inline]
> > dup_task_struct kernel/fork.c:843 [inline]
> > copy_process+0x2026/0x87a0 kernel/fork.c:1751
> > _do_fork+0x1cb/0x11d0 kernel/fork.c:2216
> > __do_sys_clone kernel/fork.c:2323 [inline]
> > __se_sys_clone kernel/fork.c:2317 [inline]
> > __x64_sys_clone+0xbf/0x150 kernel/fork.c:2317
> > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
> > entry_SYSCALL_64_after_hwframe+0x49/0xbe
> >
> > Freed by task 9325:
> > save_stack+0x43/0xd0 mm/kasan/kasan.c:448
> > set_track mm/kasan/kasan.c:460 [inline]
> > __kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
> > kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
> > __cache_free mm/slab.c:3498 [inline]
> > kmem_cache_free+0x83/0x290 mm/slab.c:3760
> > free_task_struct kernel/fork.c:163 [inline]
> > free_task+0x16e/0x1f0 kernel/fork.c:457
> > copy_process+0x1dcc/0x87a0 kernel/fork.c:2148
> > _do_fork+0x1cb/0x11d0 kernel/fork.c:2216
> > __do_sys_clone kernel/fork.c:2323 [inline]
> > __se_sys_clone kernel/fork.c:2317 [inline]
> > __x64_sys_clone+0xbf/0x150 kernel/fork.c:2317
> > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
> > entry_SYSCALL_64_after_hwframe+0x49/0xbe
> >
> > The buggy address belongs to the object at ffff8881b72ae240
> > which belongs to the cache task_struct(81:syz2) of size 6080
> > The buggy address is located 4304 bytes inside of
> > 6080-byte region [ffff8881b72ae240, ffff8881b72afa00)
> > The buggy address belongs to the page:
> > page:ffffea0006dcab80 count:1 mapcount:0 mapping:ffff8881d2dce0c0 index:0x0 compound_mapcount: 0
> > flags: 0x2fffc0000010200(slab|head)
> > raw: 02fffc0000010200 ffffea00074a1f88 ffffea0006ebbb88 ffff8881d2dce0c0
> > raw: 0000000000000000 ffff8881b72ae240 0000000100000001 ffff8881d87fe580
> > page dumped because: kasan: bad access detected
> > page->mem_cgroup:ffff8881d87fe580
> >
> > Memory state around the buggy address:
> > ffff8881b72af200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > ffff8881b72af280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> >> ffff8881b72af300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > ^
> > ffff8881b72af380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > ffff8881b72af400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > ==================================================================
> >
> >
> > .
> >
>
>
> --
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next prev parent reply other threads:[~2019-03-04 7:40 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-07 1:52 KASAN: use-after-free Read in get_mem_cgroup_from_mm syzbot
2018-12-04 15:43 ` syzbot
2019-03-03 16:19 ` zhong jiang
2019-03-04 7:40 ` Dmitry Vyukov [this message]
2019-03-04 14:00 ` zhong jiang
2019-03-04 14:11 ` Dmitry Vyukov
2019-03-04 15:32 ` zhong jiang
2019-03-05 6:26 ` Dmitry Vyukov
2019-03-05 6:42 ` zhong jiang
2019-03-06 2:05 ` Andrea Arcangeli
2019-03-06 5:53 ` zhong jiang
2019-03-06 6:26 ` Mike Rapoport
2019-03-06 7:41 ` zhong jiang
2019-03-06 8:12 ` Peter Xu
2019-03-06 13:07 ` zhong jiang
2019-03-06 18:29 ` Andrea Arcangeli
2019-03-07 7:58 ` zhong jiang
2019-03-06 8:20 ` Mike Rapoport
2019-03-08 7:10 ` zhong jiang
2019-03-15 21:39 ` Andrea Arcangeli
2019-03-16 9:38 ` zhong jiang
2019-03-16 19:42 ` Andrea Arcangeli
2019-03-18 6:23 ` zhong jiang
2019-03-04 21:51 ` Matthew Wilcox
2019-03-05 3:09 ` zhong jiang
2019-03-22 9:36 ` syzbot
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