[f2fs-dev,5.10.y] f2fs: fix to do sanity check on F2FS_INLINE_DATA flag in inode during GC

Commit Message

Vasiliy Kovalev Dec. 31, 2024, 11:57 a.m. UTC

From: Chao Yu <[e-mail]>

[ Upstream commit fc01008c92f40015aeeced94750855a7111b6929 ]

syzbot reports a f2fs bug as below:

------------[ cut here ]------------
kernel BUG at fs/f2fs/inline.c:258!
CPU: 1 PID: 34 Comm: kworker/u8:2 Not tainted 6.9.0-rc6-syzkaller-00012-g9e4bc4bcae01 #0
RIP: 0010:f2fs_write_inline_data+0x781/0x790 fs/f2fs/inline.c:258
Call Trace:
 f2fs_write_single_data_page+0xb65/0x1d60 fs/f2fs/data.c:2834
 f2fs_write_cache_pages fs/f2fs/data.c:3133 [inline]
 __f2fs_write_data_pages fs/f2fs/data.c:3288 [inline]
 f2fs_write_data_pages+0x1efe/0x3a90 fs/f2fs/data.c:3315
 do_writepages+0x35b/0x870 mm/page-writeback.c:2612
 __writeback_single_inode+0x165/0x10b0 fs/fs-writeback.c:1650
 writeback_sb_inodes+0x905/0x1260 fs/fs-writeback.c:1941
 wb_writeback+0x457/0xce0 fs/fs-writeback.c:2117
 wb_do_writeback fs/fs-writeback.c:2264 [inline]
 wb_workfn+0x410/0x1090 fs/fs-writeback.c:2304
 process_one_work kernel/workqueue.c:3254 [inline]
 process_scheduled_works+0xa12/0x17c0 kernel/workqueue.c:3335
 worker_thread+0x86d/0xd70 kernel/workqueue.c:3416
 kthread+0x2f2/0x390 kernel/kthread.c:388
 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

The root cause is: inline_data inode can be fuzzed, so that there may
be valid blkaddr in its direct node, once f2fs triggers background GC
to migrate the block, it will hit f2fs_bug_on() during dirty page
writeback.

Let's add sanity check on F2FS_INLINE_DATA flag in inode during GC,
so that, it can forbid migrating inline_data inode's data block for
fixing.

Reported-by: [e-mail]
Closes: https://lore.kernel.org/linux-f2fs-devel/[e-mail]
Signed-off-by: Chao Yu <[e-mail]>
Signed-off-by: Jaegeuk Kim <[e-mail]>
[kovalev: Replaced f2fs_err_ratelimited() with printk_ratelimited()
to use a supported function]
Signed-off-by: Vasiliy Kovalev <[e-mail]>
---
Backport to fix CVE-2024-44942
Link: https://www.cve.org/CVERecord/?id=CVE-2024-44942
---
 fs/f2fs/gc.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

Patch

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 19d781a3d305a6..64ff51c2f3d642 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1457,6 +1457,17 @@  static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
 				continue;
 			}
 
+			if (f2fs_has_inline_data(inode)) {
+				iput(inode);
+				set_sbi_flag(sbi, SBI_NEED_FSCK);
+				printk_ratelimited("%sF2FS-fs (%s): "
+					"inode %lx has both inline_data flag and "
+					"data block, nid=%u, ofs_in_node=%u",
+					KERN_INFO, sbi->sb->s_id,
+					inode->i_ino, dni.nid, ofs_in_node);
+				continue;
+			}
+
 			if (!down_write_trylock(
 				&F2FS_I(inode)->i_gc_rwsem[WRITE])) {
 				iput(inode);