From: syzbot <syzbot+a9ac39bf55329e206219@syzkaller.appspotmail.com>
To: jmorris@namei.org, keescook@chromium.org,
linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org, oleg@redhat.com,
penguin-kernel@I-love.SAKURA.ne.jp,
penguin-kernel@i-love.sakura.ne.jp, serge@hallyn.com,
syzkaller-bugs@googlegroups.com
Subject: Re: KASAN: use-after-free Read in task_is_descendant
Date: Sat, 10 Nov 2018 03:46:04 -0800 [thread overview]
Message-ID: <000000000000442753057a4e036d@google.com> (raw)
In-Reply-To: <0000000000004904df0578b7d3da@google.com>
syzbot has found a reproducer for the following crash on:
HEAD commit: aa4330e15c26 Merge tag 'devicetree-fixes-for-4.20-2' of gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17abaa47400000
kernel config: https://syzkaller.appspot.com/x/.config?x=8f559fee2fc3375a
dashboard link: https://syzkaller.appspot.com/bug?extid=a9ac39bf55329e206219
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
userspace arch: i386
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=108ae6d5400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17bd86a3400000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+a9ac39bf55329e206219@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:182
[inline]
BUG: KASAN: use-after-free in task_is_descendant.part.3+0x610/0x670
security/yama/yama_lsm.c:295
Read of size 8 at addr ffff8801ae718560 by task syz-executor198/4607
CPU: 1 PID: 4607 Comm: syz-executor198 Not tainted 4.20.0-rc1+ #232
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_is_descendant.part.3+0x610/0x670 security/yama/yama_lsm.c:295
task_is_descendant security/yama/yama_lsm.c:282 [inline]
yama_ptrace_access_check+0x215/0x10fc security/yama/yama_lsm.c:371
security_ptrace_access_check+0x54/0xb0 security/security.c:271
__ptrace_may_access+0x5c8/0x980 kernel/ptrace.c:336
ptrace_attach+0x1fa/0x640 kernel/ptrace.c:389
__do_compat_sys_ptrace kernel/ptrace.c:1284 [inline]
__se_compat_sys_ptrace kernel/ptrace.c:1266 [inline]
__ia32_compat_sys_ptrace+0x1d2/0x260 kernel/ptrace.c:1266
do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397
entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7feba29
Code: 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 14 24 c3 8b 3c 24 c3 90 90
90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90
90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f7fe71ec EFLAGS: 00000296 ORIG_RAX: 000000000000001a
RAX: ffffffffffffffda RBX: 0000000000004206 RCX: 00000000000014b5
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Allocated by task 5668:
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_compat_sys_x86_clone arch/x86/ia32/sys_ia32.c:240 [inline]
__se_compat_sys_x86_clone arch/x86/ia32/sys_ia32.c:236 [inline]
__ia32_compat_sys_x86_clone+0xbc/0x140 arch/x86/ia32/sys_ia32.c:236
do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397
entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
Freed by task 16:
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
__put_task_struct+0x2e6/0x620 kernel/fork.c:730
put_task_struct include/linux/sched/task.h:96 [inline]
delayed_put_task_struct+0x2ff/0x4c0 kernel/exit.c:181
__rcu_reclaim kernel/rcu/rcu.h:240 [inline]
rcu_do_batch kernel/rcu/tree.c:2437 [inline]
invoke_rcu_callbacks kernel/rcu/tree.c:2716 [inline]
rcu_process_callbacks+0x100a/0x1ac0 kernel/rcu/tree.c:2697
__do_softirq+0x308/0xb7e kernel/softirq.c:292
The buggy address belongs to the object at ffff8801ae718080
which belongs to the cache task_struct of size 6080
The buggy address is located 1248 bytes inside of
6080-byte region [ffff8801ae718080, ffff8801ae719840)
The buggy address belongs to the page:
page:ffffea0006b9c600 count:1 mapcount:0 mapping:ffff8801da970180 index:0x0
compound_mapcount: 0
flags: 0x2fffc0000010200(slab|head)
raw: 02fffc0000010200 ffffea0006b99488 ffffea0006b9c688 ffff8801da970180
raw: 0000000000000000 ffff8801ae718080 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8801ae718400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8801ae718480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff8801ae718500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8801ae718580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8801ae718600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
prev parent reply other threads:[~2018-11-10 11:46 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-21 7:10 KASAN: use-after-free Read in task_is_descendant syzbot
2018-10-21 7:12 ` Tetsuo Handa
2018-10-22 9:54 ` Oleg Nesterov
2018-10-22 10:06 ` Tetsuo Handa
2018-10-22 13:46 ` Oleg Nesterov
2018-10-25 2:15 ` Tetsuo Handa
2018-10-25 11:13 ` Oleg Nesterov
2018-10-25 11:36 ` Kees Cook
2018-10-25 12:05 ` Oleg Nesterov
2018-10-25 11:47 ` Tetsuo Handa
2018-10-25 12:17 ` Oleg Nesterov
2018-10-25 13:01 ` Oleg Nesterov
2018-10-26 16:09 ` Kees Cook
2018-10-29 12:23 ` Oleg Nesterov
2018-10-29 15:05 ` yama: unsafe usage of ptrace_relation->tracer Oleg Nesterov
2019-01-10 11:05 ` Tetsuo Handa
2019-01-10 18:47 ` Kees Cook
2019-01-16 17:40 ` Oleg Nesterov
2018-10-25 13:14 ` KASAN: use-after-free Read in task_is_descendant Tetsuo Handa
2018-10-25 15:55 ` Oleg Nesterov
2018-10-25 16:25 ` Oleg Nesterov
2018-10-26 12:23 ` Tetsuo Handa
2018-10-26 13:04 ` Oleg Nesterov
2018-10-26 13:51 ` Tetsuo Handa
2018-10-26 14:39 ` Oleg Nesterov
2018-10-26 15:04 ` Tetsuo Handa
2018-10-26 15:22 ` Oleg Nesterov
2018-10-25 8:19 ` Kees Cook
2018-10-25 11:52 ` Oleg Nesterov
2018-11-10 3:25 ` syzbot
2018-11-10 11:46 ` syzbot [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=000000000000442753057a4e036d@google.com \
--to=syzbot+a9ac39bf55329e206219@syzkaller.appspotmail.com \
--cc=jmorris@namei.org \
--cc=keescook@chromium.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-security-module@vger.kernel.org \
--cc=oleg@redhat.com \
--cc=penguin-kernel@I-love.SAKURA.ne.jp \
--cc=serge@hallyn.com \
--cc=syzkaller-bugs@googlegroups.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.