[syzbot] KASAN: slab-out-of-bounds Read in search_by_key (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b229b6ca5abb Merge tag 'perf-tools-fixes-for-v6.1-2022-10-..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14ff0ede880000
kernel config: https://syzkaller.appspot.com/x/.config?x=1d3548a4365ba17d
dashboard link: https://syzkaller.appspot.com/bug?extid=b3b14fb9f8a14c5d0267
compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/24728b72a896/disk-b229b6ca.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/10a3c40c60e1/vmlinux-b229b6ca.xz
kernel image: https://storage.googleapis.com/syzbot-assets/69f963b02b7e/bzImage-b229b6ca.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b3b14f...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in search_by_key+0xf2/0x49c0 fs/reiserfs/stree.c:632
Read of size 8 at addr ffff88802678e3f0 by task syz-executor.4/9639

CPU: 1 PID: 9639 Comm: syz-executor.4 Not tainted 6.1.0-rc2-syzkaller-00105-gb229b6ca5abb #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
print_address_description+0x74/0x340 mm/kasan/report.c:284
print_report+0x107/0x1f0 mm/kasan/report.c:395
kasan_report+0xcd/0x100 mm/kasan/report.c:495
search_by_key+0xf2/0x49c0 fs/reiserfs/stree.c:632
search_by_entry_key+0x36/0xd20 fs/reiserfs/namei.c:125
reiserfs_readdir_inode+0x235/0x1410 fs/reiserfs/dir.c:98
iterate_dir+0x257/0x5f0
__do_sys_getdents fs/readdir.c:286 [inline]
__se_sys_getdents+0x1db/0x4d0 fs/readdir.c:271
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f1f6208b5a9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1f62e83168 EFLAGS: 00000246 ORIG_RAX: 000000000000004e
RAX: ffffffffffffffda RBX: 00007f1f621abf80 RCX: 00007f1f6208b5a9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007f1f620e67b0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc33ce425f R14: 00007f1f62e83300 R15: 0000000000022000
</TASK>

Allocated by task 9639:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x3d/0x60 mm/kasan/common.c:52
____kasan_kmalloc mm/kasan/common.c:371 [inline]
__kasan_kmalloc+0x97/0xb0 mm/kasan/common.c:380
kmalloc include/linux/slab.h:576 [inline]
kzalloc include/linux/slab.h:712 [inline]
bfs_fill_super+0x5a/0xe30 fs/bfs/inode.c:321
mount_bdev+0x26c/0x3a0 fs/super.c:1400
legacy_get_tree+0xea/0x180 fs/fs_context.c:610
vfs_get_tree+0x88/0x270 fs/super.c:1530
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+0x2d3/0x3c0 fs/namespace.c:3568
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff88802678e200
which belongs to the cache kmalloc-256 of size 256
The buggy address is located 240 bytes to the right of
256-byte region [ffff88802678e200, ffff88802678e300)

The buggy address belongs to the physical page:
page:ffffea000099e380 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2678e
head:ffffea000099e380 order:1 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 ffffea00007c1380 dead000000000003 ffff888012041b40
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 34, tgid 34 (kworker/u4:2), ts 195026526707, free_ts 195023823133
prep_new_page mm/page_alloc.c:2538 [inline]
get_page_from_freelist+0x742/0x7c0 mm/page_alloc.c:4287
__alloc_pages+0x259/0x560 mm/page_alloc.c:5554
alloc_slab_page+0x70/0xf0 mm/slub.c:1794
allocate_slab+0x5e/0x4b0 mm/slub.c:1939
new_slab mm/slub.c:1992 [inline]
___slab_alloc+0x782/0xe20 mm/slub.c:3180
__slab_alloc mm/slub.c:3279 [inline]
slab_alloc_node mm/slub.c:3364 [inline]
__kmem_cache_alloc_node+0x252/0x310 mm/slub.c:3437
__do_kmalloc_node mm/slab_common.c:954 [inline]
__kmalloc+0x9e/0x1a0 mm/slab_common.c:968
kmalloc include/linux/slab.h:581 [inline]
kzalloc include/linux/slab.h:712 [inline]
ieee80211_ibss_build_presp+0x116/0x1920 net/mac80211/ibss.c:70
__ieee80211_sta_join_ibss+0x7b9/0x14b0 net/mac80211/ibss.c:316
ieee80211_sta_create_ibss+0x35b/0x600 net/mac80211/ibss.c:1348
ieee80211_sta_find_ibss net/mac80211/ibss.c:1478 [inline]
ieee80211_ibss_work+0xe9c/0x1540 net/mac80211/ibss.c:1705
process_one_work+0x877/0xdb0 kernel/workqueue.c:2289
worker_thread+0xb14/0x1330 kernel/workqueue.c:2436
kthread+0x266/0x300 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1458 [inline]
free_pcp_prepare+0x80c/0x8f0 mm/page_alloc.c:1508
free_unref_page_prepare mm/page_alloc.c:3386 [inline]
free_unref_page+0x7d/0x5f0 mm/page_alloc.c:3482
free_slab mm/slub.c:2031 [inline]
discard_slab mm/slub.c:2037 [inline]
__unfreeze_partials+0x1ab/0x200 mm/slub.c:2586
put_cpu_partial+0x106/0x170 mm/slub.c:2662
qlist_free_all+0x2b/0x70 mm/kasan/quarantine.c:187
kasan_quarantine_reduce+0x169/0x180 mm/kasan/quarantine.c:294
__kasan_slab_alloc+0x1f/0x70 mm/kasan/common.c:302
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slab.h:737 [inline]
slab_alloc_node mm/slub.c:3398 [inline]
slab_alloc mm/slub.c:3406 [inline]
__kmem_cache_alloc_lru mm/slub.c:3413 [inline]
kmem_cache_alloc+0x1cc/0x300 mm/slub.c:3422
getname_flags+0xb8/0x4e0 fs/namei.c:139
user_path_at_empty+0x2a/0x1a0 fs/namei.c:2875
do_readlinkat+0x10c/0x3d0 fs/stat.c:468
__do_sys_readlink fs/stat.c:501 [inline]
__se_sys_readlink fs/stat.c:498 [inline]
__x64_sys_readlink+0x7b/0x90 fs/stat.c:498
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
ffff88802678e280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88802678e300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802678e380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff88802678e400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802678e480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 861deac3b092 Linux 6.7-rc7
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=121f1609e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=e0c7078a6b901aa3
dashboard link: https://syzkaller.appspot.com/bug?extid=b3b14fb9f8a14c5d0267
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=10557e81e80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14206fd6e80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0ea60ee8ed32/disk-861deac3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/6d69fdc33021/vmlinux-861deac3.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f0158750d452/bzImage-861deac3.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/445a7c3f980d/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b3b14f...@syzkaller.appspotmail.com

REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.
=====================================================
BUG: KMSAN: uninit-value in comp_keys fs/reiserfs/stree.c:83 [inline]
BUG: KMSAN: uninit-value in bin_search fs/reiserfs/stree.c:173 [inline]
BUG: KMSAN: uninit-value in search_by_key+0x3293/0x6780 fs/reiserfs/stree.c:770
comp_keys fs/reiserfs/stree.c:83 [inline]
bin_search fs/reiserfs/stree.c:173 [inline]
search_by_key+0x3293/0x6780 fs/reiserfs/stree.c:770
reiserfs_delete_solid_item+0x4ec/0xe90 fs/reiserfs/stree.c:1419
remove_save_link+0x2ed/0x420 fs/reiserfs/super.c:540
reiserfs_truncate_file+0xd00/0x1b70 fs/reiserfs/inode.c:2314
reiserfs_setattr+0x1b79/0x1ee0 fs/reiserfs/inode.c:3388
notify_change+0x19fd/0x1af0 fs/attr.c:499
do_truncate+0x22a/0x2a0 fs/open.c:66
do_sys_ftruncate+0x81c/0xb30 fs/open.c:194
__do_sys_ftruncate fs/open.c:205 [inline]
__se_sys_ftruncate fs/open.c:203 [inline]
__x64_sys_ftruncate+0x71/0xa0 fs/open.c:203
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

Local variable cpu_key created at:
reiserfs_delete_solid_item+0xbf/0xe90 fs/reiserfs/stree.c:1410
remove_save_link+0x2ed/0x420 fs/reiserfs/super.c:540

CPU: 0 PID: 5006 Comm: syz-executor429 Not tainted 6.7.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
=====================================================


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

[Edward Adam Davis]

please test slab-out-of-bounds Read in search_by_key

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 861deac3b092

diff --git a/fs/reiserfs/stree.c b/fs/reiserfs/stree.c
index 2138ee7d271d..5faf702f8d15 100644
--- a/fs/reiserfs/stree.c
+++ b/fs/reiserfs/stree.c
@@ -1407,7 +1407,7 @@ void reiserfs_delete_solid_item(struct reiserfs_transaction_handle *th,
INITIALIZE_PATH(path);
int item_len = 0;
int tb_init = 0;
- struct cpu_key cpu_key;
+ struct cpu_key cpu_key = {};
int retval;
int quota_cut_bytes = 0;

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+b3b14f...@syzkaller.appspotmail.com

Tested on:

commit: 861deac3 Linux 6.7-rc7
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=125a5231e80000

kernel config: https://syzkaller.appspot.com/x/.config?x=e0c7078a6b901aa3
dashboard link: https://syzkaller.appspot.com/bug?extid=b3b14fb9f8a14c5d0267
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=147f47e9e80000

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

[Edward Adam Davis]

The cpu_key was not initialized in reiserfs_delete_solid_item(), which triggered
this issue.

Reported-and-tested-by: syzbot+b3b14f...@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <ead...@qq.com>
---
fs/reiserfs/stree.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/reiserfs/stree.c b/fs/reiserfs/stree.c
index 2138ee7d271d..5faf702f8d15 100644
--- a/fs/reiserfs/stree.c
+++ b/fs/reiserfs/stree.c
@@ -1407,7 +1407,7 @@ void reiserfs_delete_solid_item(struct reiserfs_transaction_handle *th,
INITIALIZE_PATH(path);
int item_len = 0;
int tb_init = 0;
- struct cpu_key cpu_key;
+ struct cpu_key cpu_key = {};
int retval;
int quota_cut_bytes = 0;

--
2.43.0

[Christian Brauner]

On Tue, 26 Dec 2023 15:16:09 +0800, Edward Adam Davis wrote:
> The cpu_key was not initialized in reiserfs_delete_solid_item(), which triggered
> this issue.
>
>

Applied to the vfs.misc branch of the vfs/vfs.git tree.
Patches in the vfs.misc branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs.misc

[1/1] reiserfs: fix uninit-value in comp_keys
https://git.kernel.org/vfs/vfs/c/dd8f87f21dc3