KASAN: use-after-free Read in squashfs_get_id

Status: fixed on 2021/02/23 13:44
Reported-by: syzbot+c021ba012da41ee9807c@syzkaller.appspotmail.com
Fix commit: f37aa4c7366e squashfs: add more sanity checks in id lookup
First crash: 2108d, last: 2012d
▶ ▼ Discussions (8)
Title Replies (including bot) Last reply
[PATCH 4.4 00/35] 4.4.258-rc1 review 43 (43) 2021/02/25 08:47
[PATCH 4.9 00/49] 4.9.258-rc1 review 54 (54) 2021/02/23 21:19
[PATCH 4.14 00/57] 4.14.222-rc1 review 60 (60) 2021/02/23 11:53
[PATCH 5.10 00/54] 5.10.16-rc1 review 68 (68) 2021/02/17 22:45
[PATCH 5.4 00/24] 5.4.98-rc1 review 31 (31) 2021/02/13 03:17
[PATCH 4.19 00/24] 4.19.176-rc1 review 34 (34) 2021/02/12 16:18
[patch 02/14] squashfs: add more sanity checks in id lookup 1 (1) 2021/02/09 21:41
[PATCH V2 2/4] Squashfs: add more sanity checks in id lookup 1 (1) 2021/02/08 07:36
▶ ▼ Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 KASAN: use-after-free Read in squashfs_get_id 19 syz, C 3 2060d 2113d 1/1 fixed on 2021/02/19 15:06
upstream KASAN: use-after-free Read in squashfs_get_id squashfs 19 syz, C error error 6 2076d 2163d 0/29 auto-obsoleted due to no activity on 2022/09/24 20:55
▶ ▼ Fix bisection attempts (5)
Created Duration User Patch Repo Result
2021/02/23 04:36 21m bisect fix linux-4.14.y OK (0) job log log
2021/02/19 02:20 18m bisect fix linux-4.14.y error job log
2021/02/17 10:11 0m bisect fix linux-4.14.y error job log
2021/01/18 09:49 22m bisect fix linux-4.14.y OK (0) job log log
2020/12/19 06:58 23m bisect fix linux-4.14.y OK (0) job log log

Sample crash report:
wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready
==================================================================
BUG: KASAN: use-after-free in squashfs_get_id+0x181/0x1a0 fs/squashfs/id.c:51
Read of size 8 at addr ffff8880afd02300 by task syz-executor182/7993

CPU: 1 PID: 7993 Comm: syz-executor182 Not tainted 4.14.207-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x283 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x194 mm/kasan/report.c:351
 kasan_report mm/kasan/report.c:409 [inline]
 __asan_report_load8_noabort+0x68/0x70 mm/kasan/report.c:430
 squashfs_get_id+0x181/0x1a0 fs/squashfs/id.c:51
 squashfs_new_inode fs/squashfs/inode.c:64 [inline]
 squashfs_read_inode+0x185/0x19e0 fs/squashfs/inode.c:133
 squashfs_fill_super+0x1501/0x1aa0 fs/squashfs/super.c:318
 mount_bdev+0x2b3/0x360 fs/super.c:1134
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0xe53/0x2a00 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3072
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x44dcda
RSP: 002b:00007fff2b2414c8 EFLAGS: 00000293 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fff2b241520 RCX: 000000000044dcda
RDX: 0000000020000000 RSI: 00000000200000c0 RDI: 00007fff2b2414e0
RBP: 0000000000000004 R08: 00007fff2b241520 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003
R13: 00007fff2b2414e0 R14: 0000000000000000 R15: 0000000020000228

Allocated by task 7993:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 __do_kmalloc mm/slab.c:3720 [inline]
 __kmalloc+0x15a/0x400 mm/slab.c:3729
 kmalloc_array include/linux/slab.h:607 [inline]
 kcalloc include/linux/slab.h:618 [inline]
 squashfs_read_table+0x76/0x18d fs/squashfs/cache.c:430
 squashfs_read_xattr_id_table+0x16a/0x200 fs/squashfs/xattr_id.c:94
 squashfs_fill_super+0xb6c/0x1aa0 fs/squashfs/super.c:233
 mount_bdev+0x2b3/0x360 fs/super.c:1134
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0xe53/0x2a00 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3072
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 7993:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xc9/0x250 mm/slab.c:3815
 squashfs_read_table+0x127/0x18d fs/squashfs/cache.c:448
 squashfs_read_xattr_id_table+0x16a/0x200 fs/squashfs/xattr_id.c:94
 squashfs_fill_super+0xb6c/0x1aa0 fs/squashfs/super.c:233
 mount_bdev+0x2b3/0x360 fs/super.c:1134
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0xe53/0x2a00 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3072
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

The buggy address belongs to the object at ffff8880afd02300
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 0 bytes inside of
 32-byte region [ffff8880afd02300, ffff8880afd02320)
The buggy address belongs to the page:
page:ffffea0002bf4080 count:1 mapcount:0 mapping:ffff8880afd02000 index:0xffff8880afd02fc1
flags: 0xfff00000000100(slab)
raw: 00fff00000000100 ffff8880afd02000 ffff8880afd02fc1 000000010000003f
raw: ffffea0002d214a0 ffffea0002bc8760 ffff88813fe821c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880afd02200: fb fb fb fb fc fc fc fc 00 fc fc fc fc fc fc fc
 ffff8880afd02280: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8880afd02300: fb fb fb fb fc fc fc fc 00 fc fc fc fc fc fc fc
                   ^
 ffff8880afd02380: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8880afd02400: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/11/19 06:44 linux-4.14.y 8961076ed318 0767f13f .config console log report syz C ci2-linux-4-14
* Struck through repros no longer work on HEAD.