From: Su Yue glass.su@suse.com

commit b0fce54b8c0d8e5f2b4c243c803c5996e73baee8 upstream.

syz reports an out of bounds read:

================================================================== BUG: KASAN: slab-out-of-bounds in ocfs2_match fs/ocfs2/dir.c:334 [inline] BUG: KASAN: slab-out-of-bounds in ocfs2_search_dirblock+0x283/0x6e0 fs/ocfs2/dir.c:367 Read of size 1 at addr ffff88804d8b9982 by task syz-executor.2/14802

CPU: 0 UID: 0 PID: 14802 Comm: syz-executor.2 Not tainted 6.13.0-rc4 #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Sched_ext: serialise (enabled+all), task: runnable_at=-10ms Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x229/0x350 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x164/0x530 mm/kasan/report.c:489 kasan_report+0x147/0x180 mm/kasan/report.c:602 ocfs2_match fs/ocfs2/dir.c:334 [inline] ocfs2_search_dirblock+0x283/0x6e0 fs/ocfs2/dir.c:367 ocfs2_find_entry_id fs/ocfs2/dir.c:414 [inline] ocfs2_find_entry+0x1143/0x2db0 fs/ocfs2/dir.c:1078 ocfs2_find_files_on_disk+0x18e/0x530 fs/ocfs2/dir.c:1981 ocfs2_lookup_ino_from_name+0xb6/0x110 fs/ocfs2/dir.c:2003 ocfs2_lookup+0x30a/0xd40 fs/ocfs2/namei.c:122 lookup_open fs/namei.c:3627 [inline] open_last_lookups fs/namei.c:3748 [inline] path_openat+0x145a/0x3870 fs/namei.c:3984 do_filp_open+0xe9/0x1c0 fs/namei.c:4014 do_sys_openat2+0x135/0x1d0 fs/open.c:1402 do_sys_open fs/open.c:1417 [inline] __do_sys_openat fs/open.c:1433 [inline] __se_sys_openat fs/open.c:1428 [inline] __x64_sys_openat+0x15d/0x1c0 fs/open.c:1428 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf6/0x210 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f01076903ad Code: c3 e8 a7 2b 00 00 0f 1f 80 00 00 00 00 f3 0f 1e fa 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:00007f01084acfc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f01077cbf80 RCX: 00007f01076903ad RDX: 0000000000105042 RSI: 0000000020000080 RDI: ffffffffffffff9c RBP: 00007f01077cbf80 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000000001ff R11: 0000000000000246 R12: 0000000000000000 R13: 00007f01077cbf80 R14: 00007f010764fc90 R15: 00007f010848d000 </TASK> ==================================================================

And a general protection fault in ocfs2_prepare_dir_for_insert:

================================================================== loop0: detected capacity change from 0 to 32768 JBD2: Ignoring recovery information on journal ocfs2: Mounting device (7,0) on (node local, slot 0) with ordered data mode. Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 0 UID: 0 PID: 5096 Comm: syz-executor792 Not tainted 6.11.0-rc4-syzkaller-00002-gb0da640826ba #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:ocfs2_find_dir_space_id fs/ocfs2/dir.c:3406 [inline] RIP: 0010:ocfs2_prepare_dir_for_insert+0x3309/0x5c70 fs/ocfs2/dir.c:4280 Code: 00 00 e8 2a 25 13 fe e9 ba 06 00 00 e8 20 25 13 fe e9 4f 01 00 00 e8 16 25 13 fe 49 8d 7f 08 49 8d 5f 09 48 89 f8 48 c1 e8 03 <42> 0f b6 04 20 84 c0 0f 85 bd 23 00 00 48 89 d8 48 c1 e8 03 42 0f RSP: 0018:ffffc9000af9f020 EFLAGS: 00010202 RAX: 0000000000000001 RBX: 0000000000000009 RCX: ffff88801e27a440 RDX: 0000000000000000 RSI: 0000000000000400 RDI: 0000000000000008 RBP: ffffc9000af9f830 R08: ffffffff8380395b R09: ffffffff838090a7 R10: 0000000000000002 R11: ffff88801e27a440 R12: dffffc0000000000 R13: ffff88803c660878 R14: f700000000000088 R15: 0000000000000000 FS: 000055555a677380(0000) GS:ffff888020800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000560bce569178 CR3: 000000001de5a000 CR4: 0000000000350ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ocfs2_mknod+0xcaf/0x2b40 fs/ocfs2/namei.c:292 vfs_mknod+0x36d/0x3b0 fs/namei.c:4088 do_mknodat+0x3ec/0x5b0 __do_sys_mknodat fs/namei.c:4166 [inline] __se_sys_mknodat fs/namei.c:4163 [inline] __x64_sys_mknodat+0xa7/0xc0 fs/namei.c:4163 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2dafda3a99 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 17 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffe336a6658 EFLAGS: 00000246 ORIG_RAX: 0000000000000103 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2dafda3a99 RDX: 00000000000021c0 RSI: 0000000020000040 RDI: 00000000ffffff9c RBP: 00007f2dafe1b5f0 R08: 0000000000004480 R09: 000055555a6784c0 R10: 0000000000000103 R11: 0000000000000246 R12: 00007ffe336a6680 R13: 00007ffe336a68a8 R14: 431bde82d7b634db R15: 00007f2dafdec03b </TASK> ==================================================================

The two reports are all caused invalid negative i_size of dir inode. For ocfs2, dir_inode can't be negative or zero.

Here add a check in which is called by ocfs2_check_dir_for_entry(). It fixes the second report as ocfs2_check_dir_for_entry() must be called before ocfs2_prepare_dir_for_insert(). Also set a up limit for dir with OCFS2_INLINE_DATA_FL. The i_size can't be great than blocksize.

Link: https://lkml.kernel.org/r/20250106140640.92260-1-glass.su@suse.com Reported-by: Jiacheng Xu stitch@zju.edu.cn Link: https://lore.kernel.org/ocfs2-devel/17a04f01.1ae74.19436d003fc.Coremail.stit... Reported-by: syzbot+5a64828fcc4c2ad9b04f@syzkaller.appspotmail.com Link: https://lore.kernel.org/all/0000000000005894f3062018caf1@google.com/T/ Signed-off-by: Su Yue glass.su@suse.com Reviewed-by: Heming Zhao heming.zhao@suse.com Reviewed-by: Joseph Qi joseph.qi@linux.alibaba.com Cc: Mark Fasheh mark@fasheh.com Cc: Joel Becker jlbec@evilplan.org Cc: Junxiao Bi junxiao.bi@oracle.com Cc: Changwei Ge gechangwei@live.cn Cc: Jun Piao piaojun@huawei.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Vasiliy Kovalev kovalev@altlinux.org --- fs/ocfs2/dir.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c index c9797dd067851..441818535bfc5 100644 --- a/fs/ocfs2/dir.c +++ b/fs/ocfs2/dir.c @@ -1065,26 +1065,39 @@ int ocfs2_find_entry(const char *name, int namelen, { struct buffer_head *bh; struct ocfs2_dir_entry *res_dir = NULL; + int ret = 0;

if (ocfs2_dir_indexed(dir)) return ocfs2_find_entry_dx(name, namelen, dir, lookup);

+ if (unlikely(i_size_read(dir) <= 0)) { + ret = -EFSCORRUPTED; + mlog_errno(ret); + goto out; + } /* * The unindexed dir code only uses part of the lookup * structure, so there's no reason to push it down further * than this. */ - if (OCFS2_I(dir)->ip_dyn_features & OCFS2_INLINE_DATA_FL) + if (OCFS2_I(dir)->ip_dyn_features & OCFS2_INLINE_DATA_FL) { + if (unlikely(i_size_read(dir) > dir->i_sb->s_blocksize)) { + ret = -EFSCORRUPTED; + mlog_errno(ret); + goto out; + } bh = ocfs2_find_entry_id(name, namelen, dir, &res_dir); - else + } else { bh = ocfs2_find_entry_el(name, namelen, dir, &res_dir); + }

if (bh == NULL) return -ENOENT;

lookup->dl_leaf_bh = bh; lookup->dl_entry = res_dir; - return 0; +out: + return ret; }

/* @@ -2011,6 +2024,7 @@ int ocfs2_lookup_ino_from_name(struct inode *dir, const char *name, * * Return 0 if the name does not exist * Return -EEXIST if the directory contains the name + * Return -EFSCORRUPTED if found corruption * * Callers should have i_mutex + a cluster lock on dir */ @@ -2024,9 +2038,12 @@ int ocfs2_check_dir_for_entry(struct inode *dir, trace_ocfs2_check_dir_for_entry( (unsigned long long)OCFS2_I(dir)->ip_blkno, namelen, name);

- if (ocfs2_find_entry(name, namelen, dir, &lookup) == 0) { + ret = ocfs2_find_entry(name, namelen, dir, &lookup); + if (ret == 0) { ret = -EEXIST; mlog_errno(ret); + } else if (ret == -ENOENT) { + ret = 0; }

ocfs2_free_dir_lookup_result(&lookup);