From: syzbot <syzbot+bbeb1c88016c7db4aa24@syzkaller.appspotmail.com>
To: arnd@arndb.de, christian.brauner@ubuntu.com, hch@lst.de,
linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, linux@dominikbrodowski.net,
syzkaller-bugs@googlegroups.com, torvalds@linux-foundation.org,
viro@zeniv.linux.org.uk
Subject: Re: KASAN: use-after-free Read in path_init (2)
Date: Wed, 12 Aug 2020 14:28:14 -0700 [thread overview]
Message-ID: <0000000000008bfef305acb4ddee@google.com> (raw)
In-Reply-To: <000000000000f0724405aca59f64@google.com>
syzbot has found a reproducer for the following issue on:
HEAD commit: fb893de3 Merge tag 'tag-chrome-platform-for-v5.9' of git:/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16139be2900000
kernel config: https://syzkaller.appspot.com/x/.config?x=f1fedc63022bf07e
dashboard link: https://syzkaller.appspot.com/bug?extid=bbeb1c88016c7db4aa24
compiler: gcc (GCC) 10.1.0-syz 20200507
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15fa83e2900000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15920c4a900000
The issue was bisected to:
commit e24ab0ef689de43649327f54cd1088f3dad25bb3
Author: Christoph Hellwig <hch@lst.de>
Date: Tue Jul 21 08:48:15 2020 +0000
fs: push the getname from do_rmdir into the callers
bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=155f36c2900000
final oops: https://syzkaller.appspot.com/x/report.txt?x=175f36c2900000
console output: https://syzkaller.appspot.com/x/log.txt?x=135f36c2900000
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+bbeb1c88016c7db4aa24@syzkaller.appspotmail.com
Fixes: e24ab0ef689d ("fs: push the getname from do_rmdir into the callers")
==================================================================
BUG: KASAN: use-after-free in path_init+0x116b/0x13c0 fs/namei.c:2207
Read of size 8 at addr ffff8880950a8a80 by task syz-executor167/6821
CPU: 0 PID: 6821 Comm: syz-executor167 Not tainted 5.8.0-syzkaller #0
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+0x18f/0x20d lib/dump_stack.c:118
print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
path_init+0x116b/0x13c0 fs/namei.c:2207
path_parentat+0x22/0x1b0 fs/namei.c:2384
filename_parentat+0x188/0x560 fs/namei.c:2407
do_rmdir+0xa8/0x440 fs/namei.c:3732
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4403e9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 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 7b 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffd4e3bdb58 EFLAGS: 00000246 ORIG_RAX: 0000000000000054
RAX: ffffffffffffffda RBX: 69662f7375622f2e RCX: 00000000004403e9
RDX: 00000000004403e9 RSI: 00000000004403e9 RDI: 0000000020000080
RBP: 2f31656c69662f2e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401bf0
R13: 0000000000401c80 R14: 0000000000000000 R15: 0000000000000000
Allocated by task 6821:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
kasan_set_track mm/kasan/common.c:56 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461
slab_post_alloc_hook mm/slab.h:518 [inline]
slab_alloc mm/slab.c:3312 [inline]
kmem_cache_alloc+0x138/0x3a0 mm/slab.c:3482
getname_flags.part.0+0x50/0x4f0 fs/namei.c:138
getname_flags include/linux/audit.h:320 [inline]
getname fs/namei.c:209 [inline]
__do_sys_rmdir fs/namei.c:3783 [inline]
__se_sys_rmdir fs/namei.c:3781 [inline]
__x64_sys_rmdir+0xb1/0x100 fs/namei.c:3781
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Freed by task 6821:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
kasan_set_track+0x1c/0x30 mm/kasan/common.c:56
kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355
__kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422
__cache_free mm/slab.c:3418 [inline]
kmem_cache_free.part.0+0x67/0x1f0 mm/slab.c:3693
putname+0xe1/0x120 fs/namei.c:259
do_rmdir+0x145/0x440 fs/namei.c:3773
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
The buggy address belongs to the object at ffff8880950a8a80
which belongs to the cache names_cache of size 4096
The buggy address is located 0 bytes inside of
4096-byte region [ffff8880950a8a80, ffff8880950a9a80)
The buggy address belongs to the page:
page:00000000c8532513 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x950a8
head:00000000c8532513 order:1 compound_mapcount:0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea0002540e88 ffffea000251ef88 ffff88821bc47a00
raw: 0000000000000000 ffff8880950a8a80 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8880950a8980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880950a8a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880950a8a80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880950a8b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880950a8b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
prev parent reply other threads:[~2020-08-12 21:28 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-12 3:17 KASAN: use-after-free Read in path_init (2) syzbot
2020-08-12 4:15 ` [PATCH] " Al Viro
2020-08-12 4:29 ` Linus Torvalds
2020-08-12 5:55 ` Al Viro
2020-08-12 17:23 ` Linus Torvalds
2020-08-12 21:28 ` 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=0000000000008bfef305acb4ddee@google.com \
--to=syzbot+bbeb1c88016c7db4aa24@syzkaller.appspotmail.com \
--cc=arnd@arndb.de \
--cc=christian.brauner@ubuntu.com \
--cc=hch@lst.de \
--cc=linux-api@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@dominikbrodowski.net \
--cc=syzkaller-bugs@googlegroups.com \
--cc=torvalds@linux-foundation.org \
--cc=viro@zeniv.linux.org.uk \
/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.