[syzbot] [hfs?] KMSAN: uninit-value in hfs_cat_keycmp (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 610a9b8f49fb Linux 6.7-rc8
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=163c9fb5e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=e51fe20c3e51ba7f
dashboard link: https://syzkaller.appspot.com/bug?extid=04486d87f6240a004c85
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: i386

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/daced691c987/disk-610a9b8f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/5e37367a7d1e/vmlinux-610a9b8f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/013b65c960ab/bzImage-610a9b8f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+04486d...@syzkaller.appspotmail.com

hfs: filesystem is marked locked, mounting read-only.
=====================================================
BUG: KMSAN: uninit-value in hfs_cat_keycmp+0x154/0x210 fs/hfs/catalog.c:178
hfs_cat_keycmp+0x154/0x210 fs/hfs/catalog.c:178
__hfs_brec_find+0x250/0x820 fs/hfs/bfind.c:75
hfs_brec_find+0x436/0x970 fs/hfs/bfind.c:138
hfs_brec_read+0x3f/0x1a0 fs/hfs/bfind.c:165
hfs_cat_find_brec+0xe6/0x400 fs/hfs/catalog.c:194
hfs_fill_super+0x1f27/0x23c0 fs/hfs/super.c:419
mount_bdev+0x3d7/0x560 fs/super.c:1650
hfs_mount+0x4d/0x60 fs/hfs/super.c:456
legacy_get_tree+0x110/0x290 fs/fs_context.c:662
vfs_get_tree+0xa5/0x520 fs/super.c:1771
do_new_mount+0x68d/0x1550 fs/namespace.c:3337
path_mount+0x73d/0x1f20 fs/namespace.c:3664
do_mount fs/namespace.c:3677 [inline]
__do_sys_mount fs/namespace.c:3886 [inline]
__se_sys_mount+0x725/0x810 fs/namespace.c:3863
__ia32_sys_mount+0xe3/0x150 fs/namespace.c:3863
do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
__do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:321
do_fast_syscall_32+0x37/0x70 arch/x86/entry/common.c:346
do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:384
entry_SYSENTER_compat_after_hwframe+0x70/0x7a

Uninit was created at:
slab_post_alloc_hook+0x129/0xa70 mm/slab.h:768
slab_alloc_node mm/slub.c:3478 [inline]
__kmem_cache_alloc_node+0x5c9/0x970 mm/slub.c:3517
__do_kmalloc_node mm/slab_common.c:1006 [inline]
__kmalloc+0x121/0x3c0 mm/slab_common.c:1020
kmalloc include/linux/slab.h:604 [inline]
hfs_find_init+0x91/0x250 fs/hfs/bfind.c:21
hfs_fill_super+0x1eb9/0x23c0 fs/hfs/super.c:416
mount_bdev+0x3d7/0x560 fs/super.c:1650
hfs_mount+0x4d/0x60 fs/hfs/super.c:456
legacy_get_tree+0x110/0x290 fs/fs_context.c:662
vfs_get_tree+0xa5/0x520 fs/super.c:1771
do_new_mount+0x68d/0x1550 fs/namespace.c:3337
path_mount+0x73d/0x1f20 fs/namespace.c:3664
do_mount fs/namespace.c:3677 [inline]
__do_sys_mount fs/namespace.c:3886 [inline]
__se_sys_mount+0x725/0x810 fs/namespace.c:3863
__ia32_sys_mount+0xe3/0x150 fs/namespace.c:3863
do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
__do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:321
do_fast_syscall_32+0x37/0x70 arch/x86/entry/common.c:346
do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:384
entry_SYSENTER_compat_after_hwframe+0x70/0x7a

CPU: 1 PID: 7246 Comm: syz-executor.0 Not tainted 6.7.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
=====================================================


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 5ad3cb0ed525 Merge tag 'for-v6.8-rc2' of git://git.kernel...
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=14fa7b8c180000
kernel config: https://syzkaller.appspot.com/x/.config?x=80c7a82a572c0de3

dashboard link: https://syzkaller.appspot.com/bug?extid=04486d87f6240a004c85
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=116f5a6a180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16cb9306180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a148235ac5b1/disk-5ad3cb0e.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4b06f4d02ad6/vmlinux-5ad3cb0e.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7fff06beed25/bzImage-5ad3cb0e.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/0c762eef88b9/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+04486d...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 64

hfs: filesystem is marked locked, mounting read-only.
=====================================================
BUG: KMSAN: uninit-value in hfs_cat_keycmp+0x154/0x210 fs/hfs/catalog.c:178
hfs_cat_keycmp+0x154/0x210 fs/hfs/catalog.c:178
__hfs_brec_find+0x250/0x820 fs/hfs/bfind.c:75
hfs_brec_find+0x436/0x970 fs/hfs/bfind.c:138
hfs_brec_read+0x3f/0x1a0 fs/hfs/bfind.c:165
hfs_cat_find_brec+0xe6/0x400 fs/hfs/catalog.c:194
hfs_fill_super+0x1f27/0x23c0 fs/hfs/super.c:419

mount_bdev+0x38f/0x510 fs/super.c:1658

hfs_mount+0x4d/0x60 fs/hfs/super.c:456
legacy_get_tree+0x110/0x290 fs/fs_context.c:662

vfs_get_tree+0xa5/0x560 fs/super.c:1779
do_new_mount+0x71f/0x15e0 fs/namespace.c:3352
path_mount+0x73d/0x1f20 fs/namespace.c:3679
do_mount fs/namespace.c:3692 [inline]
__do_sys_mount fs/namespace.c:3898 [inline]
__se_sys_mount+0x725/0x810 fs/namespace.c:3875
__x64_sys_mount+0xe4/0x140 fs/namespace.c:3875
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was created at:
slab_post_alloc_hook mm/slub.c:3819 [inline]
slab_alloc_node mm/slub.c:3860 [inline]
__do_kmalloc_node mm/slub.c:3980 [inline]
__kmalloc+0x919/0xf80 mm/slub.c:3994
kmalloc include/linux/slab.h:594 [inline]

hfs_find_init+0x91/0x250 fs/hfs/bfind.c:21
hfs_fill_super+0x1eb9/0x23c0 fs/hfs/super.c:416

mount_bdev+0x38f/0x510 fs/super.c:1658

hfs_mount+0x4d/0x60 fs/hfs/super.c:456
legacy_get_tree+0x110/0x290 fs/fs_context.c:662

vfs_get_tree+0xa5/0x560 fs/super.c:1779
do_new_mount+0x71f/0x15e0 fs/namespace.c:3352
path_mount+0x73d/0x1f20 fs/namespace.c:3679
do_mount fs/namespace.c:3692 [inline]
__do_sys_mount fs/namespace.c:3898 [inline]
__se_sys_mount+0x725/0x810 fs/namespace.c:3875
__x64_sys_mount+0xe4/0x140 fs/namespace.c:3875
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x63/0x6b

CPU: 1 PID: 5019 Comm: syz-executor380 Not tainted 6.8.0-rc6-syzkaller-00238-g5ad3cb0ed525 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
=====================================================


---
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 uninit-value in hfs_cat_keycmp

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

diff --git a/fs/hfs/bfind.c b/fs/hfs/bfind.c
index ef9498a6e88a..c74d864bc29e 100644
--- a/fs/hfs/bfind.c
+++ b/fs/hfs/bfind.c
@@ -18,7 +18,7 @@ int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd)

fd->tree = tree;
fd->bnode = NULL;
- ptr = kmalloc(tree->max_key_len * 2 + 4, GFP_KERNEL);
+ ptr = kzalloc(tree->max_key_len * 2 + 4, GFP_KERNEL);
if (!ptr)
return -ENOMEM;
fd->search_key = ptr;

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+04486d...@syzkaller.appspotmail.com

Tested on:

commit: 04b8076d Merge tag 'firewire-fixes-6.8-rc7' of git://g..
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=13467b8c180000

kernel config: https://syzkaller.appspot.com/x/.config?x=80c7a82a572c0de3
dashboard link: https://syzkaller.appspot.com/bug?extid=04486d87f6240a004c85
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=161c0bba180000

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

[Edward Adam Davis]

[Syzbot Reported]

[Fix]
Let's clear all search_key fields at alloc time.

Reported-and-tested-by: syzbot+04486d...@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <ead...@qq.com>
---
fs/hfs/bfind.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/hfs/bfind.c b/fs/hfs/bfind.c
index ef9498a6e88a..c74d864bc29e 100644
--- a/fs/hfs/bfind.c
+++ b/fs/hfs/bfind.c
@@ -18,7 +18,7 @@ int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd)

fd->tree = tree;
fd->bnode = NULL;
- ptr = kmalloc(tree->max_key_len * 2 + 4, GFP_KERNEL);
+ ptr = kzalloc(tree->max_key_len * 2 + 4, GFP_KERNEL);
if (!ptr)
return -ENOMEM;
fd->search_key = ptr;

--
2.43.0