syzbot


KASAN: use-after-free Write in udf_close_lvid

Status: upstream: reported C repro on 2022/05/24 00:17
Reported-by: syzbot+60864ed35b1073540d57@syzkaller.appspotmail.com
First crash: 124d, last: 30d

Cause bisection: introduced by (bisect log) :
commit 781d2a9a2fc7d0be53a072794dc03ef6de770f3d
Author: Jan Kara <jack@suse.cz>
Date: Mon May 3 09:39:03 2021 +0000

  udf: Check LVID earlier

Crash: KASAN: slab-out-of-bounds Write in udf_close_lvid (log)
Repro: C syz .config
similar bugs (1):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 KASAN: use-after-free Write in udf_close_lvid C error 2 277d 277d 0/1 upstream: reported C repro on 2021/12/21 15:22
Patch testing requests:
Created Duration User Patch Repo Result
2022/05/28 07:34 17m hdanton@sina.com patch https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git 97fa5887cf28 OK
2022/05/24 07:31 15m hdanton@sina.com patch upstream report log
2022/05/24 04:48 4m hdanton@sina.com patch upstream error

Sample crash report:
UDF-fs: error (device loop0): udf_fill_super: Error in udf_iget, block=96, partition=0
==================================================================
BUG: KASAN: use-after-free in udf_close_lvid+0x68a/0x980 fs/udf/super.c:2072
Write of size 1 at addr ffff8880839e0190 by task syz-executor234/3615

CPU: 1 PID: 3615 Comm: syz-executor234 Not tainted 5.18.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_address_description+0x65/0x4b0 mm/kasan/report.c:313
 print_report+0xf4/0x210 mm/kasan/report.c:429
 kasan_report+0xfb/0x130 mm/kasan/report.c:491
 udf_close_lvid+0x68a/0x980 fs/udf/super.c:2072
 udf_fill_super+0xde8/0x1b20 fs/udf/super.c:2309
 mount_bdev+0x26c/0x3a0 fs/super.c:1367
 legacy_get_tree+0xea/0x180 fs/fs_context.c:610
 vfs_get_tree+0x88/0x270 fs/super.c:1497
 do_new_mount+0x289/0xad0 fs/namespace.c:3040
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fd64e59b08a
Code: 48 c7 c2 b8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 a8 00 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fd64e546168 EFLAGS: 00000286 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fd64e5461c0 RCX: 00007fd64e59b08a
RDX: 0000000020000000 RSI: 0000000020000700 RDI: 00007fd64e546180
RBP: 000000000000000e R08: 00007fd64e5461c0 R09: 00007fd64e5466b8
R10: 0000000000000810 R11: 0000000000000286 R12: 00007fd64e546180
R13: 0000000020000350 R14: 0000000000000003 R15: 0000000000000004
 </TASK>

The buggy address belongs to the physical page:
page:ffffea00020e7800 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x839e0
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea00020e7808 ffffea00020e7808 0000000000000000
raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
 ffff8880839e0080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880839e0100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8880839e0180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                         ^
 ffff8880839e0200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880839e0280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Fix bisection attempts:
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-smack-root 2022/08/25 13:49 upstream c40e8341e3b3 4c7657cb .config log report syz C
ci-upstream-kasan-gce-smack-root 2022/07/26 04:18 upstream e0dccc3b76fb 4c7657cb .config log report syz C
ci-upstream-kasan-gce-smack-root 2022/06/25 20:51 upstream 0840a7914caa 4c7657cb .config log report syz C
* Struck through repros no longer work on HEAD.
Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-smack-root 2022/05/23 17:07 upstream 4b0986a3613c 4c7657cb .config log report syz C KASAN: use-after-free Write in udf_close_lvid
* Struck through repros no longer work on HEAD.