[syzbot] [ntfs3?] KASAN: slab-out-of-bounds Read in mi_enum_attr

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 8a696a29c690 Merge tag 'platform-drivers-x86-v6.8-2' of gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16753f17e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=9247001bfee478be
dashboard link: https://syzkaller.appspot.com/bug?extid=a426cde6dee8c2884b0b
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12c4efc3e80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16a562f3e80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e52b675ecac5/disk-8a696a29.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4fc98d5eb84b/vmlinux-8a696a29.xz
kernel image: https://storage.googleapis.com/syzbot-assets/5d4769a0b908/bzImage-8a696a29.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/d57d4609374b/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a426cd...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in mi_enum_attr+0x850/0x9e0 fs/ntfs3/record.c:246
Read of size 4 at addr ffff88807483335d by task syz-executor171/9769

CPU: 0 PID: 9769 Comm: syz-executor171 Not tainted 6.8.0-rc1-syzkaller-00356-g8a696a29c690 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x163/0x540 mm/kasan/report.c:488
kasan_report+0x142/0x170 mm/kasan/report.c:601
mi_enum_attr+0x850/0x9e0 fs/ntfs3/record.c:246
mi_find_attr+0x1c5/0x2b0 fs/ntfs3/record.c:353
ni_find_attr+0x609/0x8d0 fs/ntfs3/frecord.c:218
ntfs_readlink_hlp+0xa6/0xcb0 fs/ntfs3/inode.c:1922
ntfs_get_link+0x79/0x110 fs/ntfs3/inode.c:2068
pick_link+0x638/0xd70
step_into+0xc9f/0x1080 fs/namei.c:1871
open_last_lookups fs/namei.c:3588 [inline]
path_openat+0x187c/0x31e0 fs/namei.c:3795
do_filp_open+0x234/0x490 fs/namei.c:3825
do_sys_openat2+0x13e/0x1d0 fs/open.c:1404
do_sys_open fs/open.c:1419 [inline]
__do_sys_open fs/open.c:1427 [inline]
__se_sys_open fs/open.c:1423 [inline]
__x64_sys_open+0x225/0x270 fs/open.c:1423
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f1b33964c19
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 81 1d 00 00 90 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 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1b338d3218 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007f1b33a06708 RCX: 00007f1b33964c19
RDX: 0000000000000065 RSI: 0000000000000080 RDI: 0000000020000440
RBP: 0000000000000020 R08: 0000000000000000 R09: 0000000000000000
R10: 00007ffcb7e5f0f7 R11: 0000000000000246 R12: 00007f1b33a06700
R13: 00007f1b339d2024 R14: 0030656c69662f2e R15: 0031656c69662f2e
</TASK>

Allocated by task 5096:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x70 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:372 [inline]
__kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:389
kasan_kmalloc include/linux/kasan.h:211 [inline]
__do_kmalloc_node mm/slub.c:3981 [inline]
__kmalloc+0x22e/0x490 mm/slub.c:3994
kmalloc include/linux/slab.h:594 [inline]
tomoyo_realpath_from_path+0xcf/0x5e0 security/tomoyo/realpath.c:251
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_path_perm+0x2b7/0x730 security/tomoyo/file.c:822
security_inode_getattr+0xd3/0x120 security/security.c:2237
vfs_getattr+0x46/0x430 fs/stat.c:173
vfs_statx+0x1a5/0x4e0 fs/stat.c:248
vfs_fstatat+0x135/0x190 fs/stat.c:304
__do_sys_newfstatat fs/stat.c:468 [inline]
__se_sys_newfstatat fs/stat.c:462 [inline]
__x64_sys_newfstatat+0x117/0x190 fs/stat.c:462
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

Freed by task 5096:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x70 mm/kasan/common.c:68
kasan_save_free_info+0x4e/0x60 mm/kasan/generic.c:640
poison_slab_object+0xa6/0xe0 mm/kasan/common.c:241
__kasan_slab_free+0x34/0x60 mm/kasan/common.c:257
kasan_slab_free include/linux/kasan.h:184 [inline]
slab_free_hook mm/slub.c:2121 [inline]
slab_free mm/slub.c:4299 [inline]
kfree+0x14a/0x380 mm/slub.c:4409
tomoyo_realpath_from_path+0x5a3/0x5e0 security/tomoyo/realpath.c:286
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_path_perm+0x2b7/0x730 security/tomoyo/file.c:822
security_inode_getattr+0xd3/0x120 security/security.c:2237
vfs_getattr+0x46/0x430 fs/stat.c:173
vfs_statx+0x1a5/0x4e0 fs/stat.c:248
vfs_fstatat+0x135/0x190 fs/stat.c:304
__do_sys_newfstatat fs/stat.c:468 [inline]
__se_sys_newfstatat fs/stat.c:462 [inline]
__x64_sys_newfstatat+0x117/0x190 fs/stat.c:462
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

The buggy address belongs to the object at ffff888074832000
which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 861 bytes to the right of
allocated 4096-byte region [ffff888074832000, ffff888074833000)

The buggy address belongs to the physical page:
page:ffffea0001d20c00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x74830
head:ffffea0001d20c00 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888013042140 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 4500, tgid 4500 (udevd), ts 828902194240, free_ts 828781426813
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x1e6/0x210 mm/page_alloc.c:1533
prep_new_page mm/page_alloc.c:1540 [inline]
get_page_from_freelist+0x33ea/0x3570 mm/page_alloc.c:3311
__alloc_pages+0x255/0x680 mm/page_alloc.c:4567
__alloc_pages_node include/linux/gfp.h:238 [inline]
alloc_pages_node include/linux/gfp.h:261 [inline]
alloc_slab_page+0x5f/0x160 mm/slub.c:2190
allocate_slab mm/slub.c:2354 [inline]
new_slab+0x84/0x2f0 mm/slub.c:2407
___slab_alloc+0xd17/0x13d0 mm/slub.c:3540
__slab_alloc mm/slub.c:3625 [inline]
__slab_alloc_node mm/slub.c:3678 [inline]
slab_alloc_node mm/slub.c:3850 [inline]
__do_kmalloc_node mm/slub.c:3980 [inline]
__kmalloc+0x2dc/0x490 mm/slub.c:3994
kmalloc include/linux/slab.h:594 [inline]
tomoyo_realpath_from_path+0xcf/0x5e0 security/tomoyo/realpath.c:251
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_check_open_permission+0x255/0x500 security/tomoyo/file.c:771
security_file_open+0x66/0x560 security/security.c:2932
do_dentry_open+0x327/0x1590 fs/open.c:940
do_open fs/namei.c:3641 [inline]
path_openat+0x2823/0x31e0 fs/namei.c:3798
do_filp_open+0x234/0x490 fs/namei.c:3825
do_sys_openat2+0x13e/0x1d0 fs/open.c:1404
do_sys_open fs/open.c:1419 [inline]
__do_sys_openat fs/open.c:1435 [inline]
__se_sys_openat fs/open.c:1430 [inline]
__x64_sys_openat+0x247/0x290 fs/open.c:1430
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83
page last free pid 4500 tgid 4500 stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1140 [inline]
free_unref_page_prepare+0x959/0xa80 mm/page_alloc.c:2346
free_unref_page+0x37/0x3f0 mm/page_alloc.c:2486
discard_slab mm/slub.c:2453 [inline]
__put_partials+0xeb/0x130 mm/slub.c:2922
put_cpu_partial+0x17b/0x250 mm/slub.c:2997
__slab_free+0x2fe/0x410 mm/slub.c:4166
qlink_free mm/kasan/quarantine.c:160 [inline]
qlist_free_all+0x6d/0xd0 mm/kasan/quarantine.c:176
kasan_quarantine_reduce+0x14b/0x160 mm/kasan/quarantine.c:283
__kasan_slab_alloc+0x23/0x70 mm/kasan/common.c:324
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slub.c:3813 [inline]
slab_alloc_node mm/slub.c:3860 [inline]
kmem_cache_alloc_lru+0x172/0x340 mm/slub.c:3879
__d_alloc+0x31/0x750 fs/dcache.c:1624
d_alloc+0x4b/0x190 fs/dcache.c:1704
lookup_one_qstr_excl+0xce/0x250 fs/namei.c:1604
do_unlinkat+0x297/0x830 fs/namei.c:4386
__do_sys_unlink fs/namei.c:4446 [inline]
__se_sys_unlink fs/namei.c:4444 [inline]
__x64_sys_unlink+0x49/0x50 fs/namei.c:4444
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

Memory state around the buggy address:
ffff888074833200: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888074833280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888074833300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff888074833380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888074833400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
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[syzbot]

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***

Subject: Re: [syzbot] [ntfs3?] KASAN: slab-out-of-bounds Read in mi_enum_attr
Author: lizh...@windriver.com

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

diff --git a/fs/ntfs3/record.c b/fs/ntfs3/record.c
index 53629b1f65e9..a435df98c2b1 100644
--- a/fs/ntfs3/record.c
+++ b/fs/ntfs3/record.c
@@ -243,14 +243,14 @@ struct ATTRIB *mi_enum_attr(struct mft_inode *mi, struct ATTRIB *attr)
off += asize;
}

- asize = le32_to_cpu(attr->size);
-
/* Can we use the first field (attr->type). */
if (off + 8 > used) {
static_assert(ALIGN(sizeof(enum ATTR_TYPE), 8) == 8);
return NULL;
}

+ asize = le32_to_cpu(attr->size);
+
if (attr->type == ATTR_END) {
/* End of enumeration. */
return NULL;

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+a426cd...@syzkaller.appspotmail.com

Tested on:

commit: 02153319 Kconfig: Disable -Wstringop-overflow for GCC ..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=101765d3e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=ac580c73b7cf3629

dashboard link: https://syzkaller.appspot.com/bug?extid=a426cde6dee8c2884b0b
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=10e774b7e80000

Note: testing is done by a robot and is best-effort only.

[Lizhi Xu]

When the value of attr->size is too large, it can cause overflow when taking
the next attr. Here, off is used to determine the offset first to avoid problems.

Reported-and-tested-by: syzbot+a426cd...@syzkaller.appspotmail.com
Signed-off-by: Lizhi Xu <lizh...@windriver.com>
---
fs/ntfs3/record.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/ntfs3/record.c b/fs/ntfs3/record.c
index 53629b1f65e9..a435df98c2b1 100644
--- a/fs/ntfs3/record.c
+++ b/fs/ntfs3/record.c
@@ -243,14 +243,14 @@ struct ATTRIB *mi_enum_attr(struct mft_inode *mi, struct ATTRIB *attr)
off += asize;
}

- asize = le32_to_cpu(attr->size);
-
/* Can we use the first field (attr->type). */
if (off + 8 > used) {
static_assert(ALIGN(sizeof(enum ATTR_TYPE), 8) == 8);
return NULL;
}

+ asize = le32_to_cpu(attr->size);
+
if (attr->type == ATTR_END) {
/* End of enumeration. */
return NULL;

--
2.43.0