syzbot


KASAN: slab-out-of-bounds Read in ntfs_attr_find

Status: fixed on 2020/12/23 11:20
Reported-by: syzbot+c77e7a332f782109bef2@syzkaller.appspotmail.com
Fix commit: dff5d7741195 ntfs: add check for mft record size in superblock
First crash: 1516d, last: 1459d
Fix bisection: fixed by (bisect log) :
commit dff5d774119537355b01e5b503d9468228d65044
Author: Rustam Kovhaev <rkovhaev@gmail.com>
Date: Tue Oct 13 23:48:17 2020 +0000

  ntfs: add check for mft record size in superblock

  
Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: use-after-free Read in ntfs_attr_find ntfs3 C done 74 652d 818d 22/28 fixed on 2023/02/24 13:50
upstream KASAN: slab-out-of-bounds Read in ntfs_attr_find ntfs3 C done 9 1499d 2424d 15/28 fixed on 2020/11/16 12:12
linux-4.14 KASAN: slab-out-of-bounds Read in ntfs_attr_find C done 10 1492d 1520d 1/1 fixed on 2020/11/20 16:27
linux-5.15 KASAN: slab-out-of-bounds Read in ntfs_attr_find 1 577d 577d 0/3 auto-obsoleted due to no activity on 2023/08/22 04:27
linux-4.14 KASAN: slab-out-of-bounds Read in ntfs_attr_find (2) C 31 633d 819d 0/1 upstream: reported C repro on 2022/08/25 11:21
Fix bisection attempts (2)
Created Duration User Patch Repo Result
2020/12/22 20:50 3h22m bisect fix linux-4.19.y OK (1) job log
2020/11/22 20:18 31m bisect fix linux-4.19.y OK (0) job log log

Sample crash report:
audit: type=1400 audit(1603222015.122:8): avc:  denied  { execmem } for  pid=6500 comm="syz-executor487" scontext=system_u:system_r:kernel_t:s0 tcontext=system_u:system_r:kernel_t:s0 tclass=process permissive=1
ntfs: (device loop0): is_boot_sector_ntfs(): Invalid end of sector marker.
==================================================================
BUG: KASAN: slab-out-of-bounds in ntfs_attr_find+0xa42/0xb70 fs/ntfs/attrib.c:613
Read of size 4 at addr ffff8880a41f423f by task syz-executor487/6500

CPU: 1 PID: 6500 Comm: syz-executor487 Not tainted 4.19.152-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+0x22c/0x33e lib/dump_stack.c:118
 print_address_description.cold+0x56/0x25c mm/kasan/report.c:256
 kasan_report_error.cold+0x66/0xb9 mm/kasan/report.c:354
 kasan_report mm/kasan/report.c:412 [inline]
 __asan_report_load_n_noabort+0x8b/0xa0 mm/kasan/report.c:443
 ntfs_attr_find+0xa42/0xb70 fs/ntfs/attrib.c:613
 ntfs_attr_lookup+0x1087/0x2060 fs/ntfs/attrib.c:1203
 ntfs_read_inode_mount+0x7e4/0x23b0 fs/ntfs/inode.c:1858
 ntfs_fill_super+0x1761/0x89d2 fs/ntfs/super.c:2871
 mount_bdev+0x2fc/0x3b0 fs/super.c:1158
 mount_fs+0xa3/0x318 fs/super.c:1261
 vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
 vfs_kern_mount fs/namespace.c:951 [inline]
 do_new_mount fs/namespace.c:2469 [inline]
 do_mount+0x51c/0x2f10 fs/namespace.c:2799
 ksys_mount+0xcf/0x130 fs/namespace.c:3015
 __do_sys_mount fs/namespace.c:3029 [inline]
 __se_sys_mount fs/namespace.c:3026 [inline]
 __x64_sys_mount+0xba/0x150 fs/namespace.c:3026
 do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x44c1fa
Code: b8 08 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 fd ad fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 da ad fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007fff8f7b42f8 EFLAGS: 00000287 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fff8f7b4350 RCX: 000000000044c1fa
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fff8f7b4310
RBP: 00007fff8f7b4310 R08: 00007fff8f7b4350 R09: 00007fff00000015
R10: 0000000000000000 R11: 0000000000000287 R12: 000000000000025d
R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000000003

Allocated by task 6500:
 kmem_cache_alloc+0x126/0x4a0 mm/slab.c:3559
 getname_flags+0xce/0x590 fs/namei.c:140
 user_path_at_empty+0x2a/0x50 fs/namei.c:2609
 user_path_at include/linux/namei.h:57 [inline]
 vfs_statx+0x113/0x210 fs/stat.c:185
 vfs_stat include/linux/fs.h:3133 [inline]
 __do_sys_newstat fs/stat.c:337 [inline]
 __se_sys_newstat+0x96/0x120 fs/stat.c:333
 do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 6500:
 __cache_free mm/slab.c:3503 [inline]
 kmem_cache_free+0x7f/0x2b0 mm/slab.c:3765
 putname+0xe1/0x130 fs/namei.c:261
 filename_lookup+0x3d0/0x5a0 fs/namei.c:2358
 user_path_at include/linux/namei.h:57 [inline]
 vfs_statx+0x113/0x210 fs/stat.c:185
 vfs_stat include/linux/fs.h:3133 [inline]
 __do_sys_newstat fs/stat.c:337 [inline]
 __se_sys_newstat+0x96/0x120 fs/stat.c:333
 do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8880a41f47c0
 which belongs to the cache names_cache of size 4096
The buggy address is located 1409 bytes to the left of
 4096-byte region [ffff8880a41f47c0, ffff8880a41f57c0)
The buggy address belongs to the page:
page:ffffea0002907d00 count:1 mapcount:0 mapping:ffff88821bc44b00 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffffea000290ed88 ffffea000240a888 ffff88821bc44b00
raw: 0000000000000000 ffff8880a41f47c0 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a41f4100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a41f4180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880a41f4200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                        ^
 ffff8880a41f4280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a41f4300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (10):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/10/20 20:06 linux-4.19.y ad326970d25c ff4a3345 .config console log report syz C ci2-linux-4-19
2020/10/14 02:18 linux-4.19.y a1b977b49b66 fc7735a2 .config console log report syz C ci2-linux-4-19
2020/10/04 00:50 linux-4.19.y b09c34517e1a 1a3f9408 .config console log report syz C ci2-linux-4-19
2020/10/23 20:18 linux-4.19.y ad326970d25c 2bb6666c .config console log report info ci2-linux-4-19
2020/10/21 12:31 linux-4.19.y ad326970d25c 99c64d5c .config console log report info ci2-linux-4-19
2020/10/15 21:47 linux-4.19.y a1b977b49b66 6e262c73 .config console log report info ci2-linux-4-19
2020/10/10 10:31 linux-4.19.y a1b977b49b66 b74c49a6 .config console log report info ci2-linux-4-19
2020/10/03 17:40 linux-4.19.y b09c34517e1a 1a3f9408 .config console log report info ci2-linux-4-19
2020/09/28 09:40 linux-4.19.y 10ad6cfd5736 6bfdbe89 .config console log report info ci2-linux-4-19
2020/09/27 00:52 linux-4.19.y 10ad6cfd5736 5dd8aee8 .config console log report info ci2-linux-4-19
* Struck through repros no longer work on HEAD.