[syzbot] [hfs?] KASAN: slab-use-after-free Read in hfsplus_read_wrapper (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: fe46a7dd189e Merge tag 'sound-6.9-rc1' of git://git.kernel..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=165f4ad9180000
kernel config: https://syzkaller.appspot.com/x/.config?x=1a07d5da4eb21586
dashboard link: https://syzkaller.appspot.com/bug?extid=fa7b3ab32bcb56c10961
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12d96e76180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13b52579180000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b42ab0fd4947/disk-fe46a7dd.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b8a6e7231930/vmlinux-fe46a7dd.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4fbf3e4ce6f8/bzImage-fe46a7dd.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/d71f61687d0b/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fa7b3a...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in hfsplus_read_wrapper+0xf86/0x1070 fs/hfsplus/wrapper.c:226
Read of size 2 at addr ffff888024fba400 by task syz-executor204/5218

CPU: 1 PID: 5218 Comm: syz-executor204 Not tainted 6.8.0-syzkaller-08951-gfe46a7dd189e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
print_address_description mm/kasan/report.c:377 [inline]
print_report+0xc3/0x620 mm/kasan/report.c:488
kasan_report+0xd9/0x110 mm/kasan/report.c:601
hfsplus_read_wrapper+0xf86/0x1070 fs/hfsplus/wrapper.c:226
hfsplus_fill_super+0x352/0x1bc0 fs/hfsplus/super.c:419
mount_bdev+0x1e6/0x2d0 fs/super.c:1658
legacy_get_tree+0x10c/0x220 fs/fs_context.c:662
vfs_get_tree+0x92/0x380 fs/super.c:1779
do_new_mount fs/namespace.c:3352 [inline]
path_mount+0x14e6/0x1f20 fs/namespace.c:3679
do_mount fs/namespace.c:3692 [inline]
__do_sys_mount fs/namespace.c:3898 [inline]
__se_sys_mount fs/namespace.c:3875 [inline]
__x64_sys_mount+0x297/0x320 fs/namespace.c:3875
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xd5/0x260 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7f706ca0c69a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 5e 04 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007ffcd3a1c1c8 EFLAGS: 00000286 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f706ca0c69a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffcd3a1c210
RBP: 0000000000000004 R08: 00007ffcd3a1c250 R09: 0000000000000632
R10: 0000000000000050 R11: 0000000000000286 R12: 00007ffcd3a1c210
R13: 00007ffcd3a1c250 R14: 0000000000080000 R15: 0000000000000003
</TASK>

The buggy address belongs to the object at ffff888024fba400
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 0 bytes inside of
freed 512-byte region [ffff888024fba400, ffff888024fba600)

The buggy address belongs to the physical page:
page:ffffea000093ee00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x24fb8
head:ffffea000093ee00 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888015041c80 0000000000000000 dead000000000001
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 4522, tgid 4522 (udevd), ts 49858478025, free_ts 49837791007
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x2d4/0x350 mm/page_alloc.c:1533
prep_new_page mm/page_alloc.c:1540 [inline]
get_page_from_freelist+0xa28/0x3780 mm/page_alloc.c:3311
__alloc_pages+0x22b/0x2410 mm/page_alloc.c:4569
__alloc_pages_node include/linux/gfp.h:238 [inline]
alloc_pages_node include/linux/gfp.h:261 [inline]
alloc_slab_page mm/slub.c:2175 [inline]
allocate_slab mm/slub.c:2338 [inline]
new_slab+0xcc/0x3a0 mm/slub.c:2391
___slab_alloc+0x66d/0x1790 mm/slub.c:3525
__slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3610
__slab_alloc_node mm/slub.c:3663 [inline]
slab_alloc_node mm/slub.c:3835 [inline]
kmalloc_trace+0x2fb/0x330 mm/slub.c:3992
kmalloc include/linux/slab.h:628 [inline]
kzalloc include/linux/slab.h:749 [inline]
kernfs_fop_open+0x28b/0xd40 fs/kernfs/file.c:621
do_dentry_open+0x8dd/0x18c0 fs/open.c:955
do_open fs/namei.c:3642 [inline]
path_openat+0x1dfb/0x2990 fs/namei.c:3799
do_filp_open+0x1dc/0x430 fs/namei.c:3826
do_sys_openat2+0x17a/0x1e0 fs/open.c:1406
do_sys_open fs/open.c:1421 [inline]
__do_sys_openat fs/open.c:1437 [inline]
__se_sys_openat fs/open.c:1432 [inline]
__x64_sys_openat+0x175/0x210 fs/open.c:1432
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xd5/0x260 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x6d/0x75
page last free pid 4529 tgid 4529 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+0x527/0xb10 mm/page_alloc.c:2346
free_unref_page+0x33/0x3c0 mm/page_alloc.c:2486
__put_partials+0x14c/0x170 mm/slub.c:2906
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x4e/0x140 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:322
kasan_slab_alloc include/linux/kasan.h:201 [inline]
slab_post_alloc_hook mm/slub.c:3798 [inline]
slab_alloc_node mm/slub.c:3845 [inline]
kmem_cache_alloc_node+0x177/0x340 mm/slub.c:3888
__alloc_skb+0x2b1/0x380 net/core/skbuff.c:658
alloc_skb include/linux/skbuff.h:1318 [inline]
netlink_alloc_large_skb+0x69/0x130 net/netlink/af_netlink.c:1210
netlink_sendmsg+0x689/0xd70 net/netlink/af_netlink.c:1880
sock_sendmsg_nosec net/socket.c:730 [inline]
__sock_sendmsg net/socket.c:745 [inline]
____sys_sendmsg+0xab8/0xc90 net/socket.c:2584
___sys_sendmsg+0x135/0x1e0 net/socket.c:2638
__sys_sendmsg+0x117/0x1f0 net/socket.c:2667
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xd5/0x260 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x6d/0x75

Memory state around the buggy address:
ffff888024fba300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff888024fba380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888024fba400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888024fba480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888024fba500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
hfsplus: unable to set blocksize to 1024!
hfsplus: unable to find HFS+ superblock


---
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syzbot engineers can be reached at syzk...@googlegroups.com.

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If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

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.

If you want to overwrite report's subsystems, reply with:
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If the report is a duplicate of another one, reply with:
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If you want to undo deduplication, reply with:
#syz undup

[Lizhi Xu]

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git fe46a7dd189e

diff --git a/fs/hfsplus/wrapper.c b/fs/hfsplus/wrapper.c
index ce9346099c72..31ae9f95c3aa 100644
--- a/fs/hfsplus/wrapper.c
+++ b/fs/hfsplus/wrapper.c
@@ -179,16 +179,13 @@ int hfsplus_read_wrapper(struct super_block *sb)
sbi->s_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
if (!sbi->s_vhdr_buf)
goto out;
- sbi->s_backup_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
- if (!sbi->s_backup_vhdr_buf)
- goto out_free_vhdr;

reread:
error = hfsplus_submit_bio(sb, part_start + HFSPLUS_VOLHEAD_SECTOR,
sbi->s_vhdr_buf, (void **)&sbi->s_vhdr,
REQ_OP_READ);
if (error)
- goto out_free_backup_vhdr;
+ goto out_free_vhdr;

error = -EINVAL;
switch (sbi->s_vhdr->signature) {
@@ -199,7 +196,7 @@ int hfsplus_read_wrapper(struct super_block *sb)
break;
case cpu_to_be16(HFSP_WRAP_MAGIC):
if (!hfsplus_read_mdb(sbi->s_vhdr, &wd))
- goto out_free_backup_vhdr;
+ goto out_free_vhdr;
wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT;
part_start += (sector_t)wd.ablk_start +
(sector_t)wd.embed_start * wd.ablk_size;
@@ -212,10 +209,13 @@ int hfsplus_read_wrapper(struct super_block *sb)
* (should do this only for cdrom/loop though)
*/
if (hfs_part_find(sb, &part_start, &part_size))
- goto out_free_backup_vhdr;
+ goto out_free_vhdr;
goto reread;
}

+ sbi->s_backup_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
+ if (!sbi->s_backup_vhdr_buf)
+ goto out_free_backup_vhdr;
error = hfsplus_submit_bio(sb, part_start + part_size - 2,
sbi->s_backup_vhdr_buf,
(void **)&sbi->s_backup_vhdr, REQ_OP_READ);
--
2.43.0

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+fa7b3a...@syzkaller.appspotmail.com

Tested on:

commit: fe46a7dd Merge tag 'sound-6.9-rc1' of git://git.kernel..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=113e1cc5180000

kernel config: https://syzkaller.appspot.com/x/.config?x=1a07d5da4eb21586
dashboard link: https://syzkaller.appspot.com/bug?extid=fa7b3ab32bcb56c10961
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=17a2321d180000

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

[Lizhi Xu]

[Syzbot reported]

[Fix]
When the logical_block_size was changed from 512 to 2048, it resulted in
insufficient space pre allocated to s_backup_vhdr_buf. To solve this problem,
move the memory allocation of s_backup_vhdr_buf to after the logical_block_size
has been changed.

Reported-and-tested-by: syzbot+fa7b3a...@syzkaller.appspotmail.com
Signed-off-by: Lizhi Xu <lizh...@windriver.com>
---
fs/hfsplus/wrapper.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/fs/hfsplus/wrapper.c b/fs/hfsplus/wrapper.c
index ce9346099c72..974786e30259 100644

+ goto out_free_vhdr;

[Lizhi Xu]

[Syzbot reported]