[syzbot] KMSAN: uninit-value in hfsplus_attr_bin_cmp_key

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: a472f15b3d1e kmsan: allow using __msan_instrument_asm_stor..
git tree: https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=14886381880000
kernel config: https://syzkaller.appspot.com/x/.config?x=1429f86b132e6d40
dashboard link: https://syzkaller.appspot.com/bug?extid=c6d8e1bffb0970780d5c
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project.git 610139d2d9ce6746b3c617fb3e2f7886272d26ff), GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: i386

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a8bf743ab4c3/disk-a472f15b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7248eae68bc7/vmlinux-a472f15b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0e33e55592a5/bzImage-a472f15b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c6d8e1...@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in hfsplus_attr_bin_cmp_key+0xed/0x180 fs/hfsplus/attributes.c:42
hfsplus_attr_bin_cmp_key+0xed/0x180 fs/hfsplus/attributes.c:42
hfs_find_rec_by_key+0xac/0x240 fs/hfsplus/bfind.c:100
__hfsplus_brec_find+0x27a/0x7d0 fs/hfsplus/bfind.c:135
hfsplus_brec_find+0x46a/0x9d0 fs/hfsplus/bfind.c:195
hfsplus_find_attr+0x308/0x380
__hfsplus_getxattr+0x380/0xe50 fs/hfsplus/xattr.c:522
hfsplus_getxattr+0x11f/0x1d0 fs/hfsplus/xattr.c:590
hfsplus_security_getxattr+0x4f/0x60 fs/hfsplus/xattr_security.c:20
__vfs_getxattr+0x699/0x6f0 fs/xattr.c:407
cap_inode_need_killpriv+0x52/0xb0 security/commoncap.c:301
security_inode_need_killpriv+0x8f/0x140 security/security.c:1422
dentry_needs_remove_privs+0x1b4/0x3f0 fs/inode.c:1995
do_truncate+0x11f/0x2d0 fs/open.c:57
handle_truncate fs/namei.c:3216 [inline]
do_open fs/namei.c:3561 [inline]
path_openat+0x4cf7/0x5600 fs/namei.c:3713
do_filp_open+0x249/0x660 fs/namei.c:3740
do_sys_openat2+0x1f0/0x910 fs/open.c:1310
do_sys_open fs/open.c:1326 [inline]
__do_sys_creat fs/open.c:1402 [inline]
__se_sys_creat fs/open.c:1396 [inline]
__ia32_sys_creat+0xed/0x160 fs/open.c:1396
do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
__do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178
do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246
entry_SYSENTER_compat_after_hwframe+0x70/0x82

Uninit was created at:
slab_post_alloc_hook mm/slab.h:742 [inline]
slab_alloc_node mm/slub.c:3398 [inline]
__kmem_cache_alloc_node+0x6ee/0xc90 mm/slub.c:3437
__do_kmalloc_node mm/slab_common.c:954 [inline]
__kmalloc+0x11d/0x3c0 mm/slab_common.c:968
kmalloc include/linux/slab.h:558 [inline]
hfsplus_find_init+0x8d/0x250 fs/hfsplus/bfind.c:21
__hfsplus_getxattr+0x2d1/0xe50 fs/hfsplus/xattr.c:516
hfsplus_getxattr+0x11f/0x1d0 fs/hfsplus/xattr.c:590
hfsplus_security_getxattr+0x4f/0x60 fs/hfsplus/xattr_security.c:20
__vfs_getxattr+0x699/0x6f0 fs/xattr.c:407
cap_inode_need_killpriv+0x52/0xb0 security/commoncap.c:301
security_inode_need_killpriv+0x8f/0x140 security/security.c:1422
dentry_needs_remove_privs+0x1b4/0x3f0 fs/inode.c:1995
do_truncate+0x11f/0x2d0 fs/open.c:57
handle_truncate fs/namei.c:3216 [inline]
do_open fs/namei.c:3561 [inline]
path_openat+0x4cf7/0x5600 fs/namei.c:3713
do_filp_open+0x249/0x660 fs/namei.c:3740
do_sys_openat2+0x1f0/0x910 fs/open.c:1310
do_sys_open fs/open.c:1326 [inline]
__do_sys_creat fs/open.c:1402 [inline]
__se_sys_creat fs/open.c:1396 [inline]
__ia32_sys_creat+0xed/0x160 fs/open.c:1396
do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
__do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178
do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246
entry_SYSENTER_compat_after_hwframe+0x70/0x82

CPU: 0 PID: 3846 Comm: syz-executor.3 Not tainted 6.1.0-rc6-syzkaller-63555-ga472f15b3d1e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
=====================================================


---
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See https://goo.gl/tpsmEJ for more information about syzbot.
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syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 04b8076df253 Merge tag 'firewire-fixes-6.8-rc7' of git://g..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=175aa96a180000
kernel config: https://syzkaller.appspot.com/x/.config?x=80c7a82a572c0de3
dashboard link: https://syzkaller.appspot.com/bug?extid=c6d8e1bffb0970780d5c
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=173516ee180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12fd7bba180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a4610b1ff2a7/disk-04b8076d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/991e9d902d39/vmlinux-04b8076d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a5b8e8e98121/bzImage-04b8076d.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/111a30273774/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c6d8e1...@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 1024
=====================================================
BUG: KMSAN: uninit-value in hfsplus_attr_bin_cmp_key+0xf1/0x190 fs/hfsplus/attributes.c:42
hfsplus_attr_bin_cmp_key+0xf1/0x190 fs/hfsplus/attributes.c:42
hfs_find_rec_by_key+0xb0/0x240 fs/hfsplus/bfind.c:100
__hfsplus_brec_find+0x26b/0x7b0 fs/hfsplus/bfind.c:135
hfsplus_brec_find+0x445/0x970 fs/hfsplus/bfind.c:195
hfsplus_find_attr+0x30c/0x390
hfsplus_attr_exists+0x1c6/0x260 fs/hfsplus/attributes.c:182
__hfsplus_setxattr+0x510/0x3580 fs/hfsplus/xattr.c:336
hfsplus_setxattr+0x129/0x1e0 fs/hfsplus/xattr.c:434
hfsplus_trusted_setxattr+0x55/0x70 fs/hfsplus/xattr_trusted.c:30
__vfs_setxattr+0x7aa/0x8b0 fs/xattr.c:201
__vfs_setxattr_noperm+0x24f/0xa30 fs/xattr.c:235
__vfs_setxattr_locked+0x441/0x480 fs/xattr.c:296
vfs_setxattr+0x294/0x650 fs/xattr.c:322
do_setxattr fs/xattr.c:630 [inline]
setxattr+0x45f/0x540 fs/xattr.c:653
path_setxattr+0x1f5/0x3c0 fs/xattr.c:672
__do_sys_setxattr fs/xattr.c:688 [inline]
__se_sys_setxattr fs/xattr.c:684 [inline]
__x64_sys_setxattr+0xf7/0x180 fs/xattr.c:684
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]
hfsplus_find_init+0x91/0x250 fs/hfsplus/bfind.c:21
hfsplus_attr_exists+0xde/0x260 fs/hfsplus/attributes.c:178
__hfsplus_setxattr+0x510/0x3580 fs/hfsplus/xattr.c:336
hfsplus_setxattr+0x129/0x1e0 fs/hfsplus/xattr.c:434
hfsplus_trusted_setxattr+0x55/0x70 fs/hfsplus/xattr_trusted.c:30
__vfs_setxattr+0x7aa/0x8b0 fs/xattr.c:201
__vfs_setxattr_noperm+0x24f/0xa30 fs/xattr.c:235
__vfs_setxattr_locked+0x441/0x480 fs/xattr.c:296
vfs_setxattr+0x294/0x650 fs/xattr.c:322
do_setxattr fs/xattr.c:630 [inline]
setxattr+0x45f/0x540 fs/xattr.c:653
path_setxattr+0x1f5/0x3c0 fs/xattr.c:672
__do_sys_setxattr fs/xattr.c:688 [inline]
__se_sys_setxattr fs/xattr.c:684 [inline]
__x64_sys_setxattr+0xf7/0x180 fs/xattr.c:684
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: 0 PID: 5013 Comm: syz-executor247 Not tainted 6.8.0-rc6-syzkaller-00250-g04b8076df253 #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 hfsplus_attr_bin_cmp_key

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

diff --git a/fs/hfsplus/bfind.c b/fs/hfsplus/bfind.c
index ca2ba8c9f82e..b939dc879dac 100644
--- a/fs/hfsplus/bfind.c
+++ b/fs/hfsplus/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+c6d8e1...@syzkaller.appspotmail.com

Tested on:

commit: 90d35da6 Linux 6.8-rc7
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=177befac180000
kernel config: https://syzkaller.appspot.com/x/.config?x=db27810a659d0b3d

dashboard link: https://syzkaller.appspot.com/bug?extid=c6d8e1bffb0970780d5c
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=17bbefac180000

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+c6d8e1...@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <ead...@qq.com>
---
fs/hfsplus/bfind.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/hfsplus/bfind.c b/fs/hfsplus/bfind.c
index ca2ba8c9f82e..b939dc879dac 100644
--- a/fs/hfsplus/bfind.c
+++ b/fs/hfsplus/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