linux-kernel - [PATCH v2] f2fs: fix to do sanity check for inline inode

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Message-Id: <20220514080102.2246-1-chao@kernel.org>
Date:   Sat, 14 May 2022 16:01:02 +0800
From:   Chao Yu <chao@...nel.org>
To:     jaegeuk@...nel.org
Cc:     linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org, Chao Yu <chao@...nel.org>,
        stable@...r.kernel.org, Ming Yan <yanming@....edu.cn>,
        Chao Yu <chao.yu@...o.com>
Subject: [PATCH v2] f2fs: fix to do sanity check for inline inode

As Yanming reported in bugzilla:

https://bugzilla.kernel.org/show_bug.cgi?id=215895

I have encountered a bug in F2FS file system in kernel v5.17.

The kernel message is shown below:

kernel BUG at fs/inode.c:611!
Call Trace:
 evict+0x282/0x4e0
 __dentry_kill+0x2b2/0x4d0
 dput+0x2dd/0x720
 do_renameat2+0x596/0x970
 __x64_sys_rename+0x78/0x90
 do_syscall_64+0x3b/0x90

The root cause is: fuzzed inode has both inline_data flag and encrypted
flag, so after it was deleted by rename(), during f2fs_evict_inode(),
it will cause inline data conversion due to flags confilction, then
page cache will be polluted and trigger panic in clear_inode().

This patch tries to fix the issue by do more sanity checks for inline
data inode in sanity_check_inode().

Cc: stable@...r.kernel.org
Reported-by: Ming Yan <yanming@....edu.cn>
Signed-off-by: Chao Yu <chao.yu@...o.com>
---
v2:
- fix to check inode type in f2fs_post_read_required()
 fs/f2fs/f2fs.h  | 8 ++++++++
 fs/f2fs/inode.c | 3 +--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 492af5b96de1..0dc2461ef02c 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -4126,6 +4126,14 @@ static inline void f2fs_set_encrypted_inode(struct inode *inode)
  */
 static inline bool f2fs_post_read_required(struct inode *inode)
 {
+	/*
+	 * used by sanity_check_inode(), when disk layout fields has not
+	 * been synchronized to inmem fields.
+	 */
+	if (S_ISREG(inode->i_mode) && (file_is_encrypt(inode) ||
+		F2FS_I(inode)->i_flags & F2FS_COMPR_FL ||
+		file_is_verity(inode)))
+		return true;
 	return f2fs_encrypted_file(inode) || fsverity_active(inode) ||
 		f2fs_compressed_file(inode);
 }
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index 2fce8fa0dac8..5e494c98e3c2 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -276,8 +276,7 @@ static bool sanity_check_inode(struct inode *inode, struct page *node_page)
 		}
 	}
 
-	if (f2fs_has_inline_data(inode) &&
-			(!S_ISREG(inode->i_mode) && !S_ISLNK(inode->i_mode))) {
+	if (f2fs_has_inline_data(inode) && !f2fs_may_inline_data(inode)) {
 		set_sbi_flag(sbi, SBI_NEED_FSCK);
 		f2fs_warn(sbi, "%s: inode (ino=%lx, mode=%u) should not have inline_data, run fsck to fix",
 			  __func__, inode->i_ino, inode->i_mode);
-- 
2.32.0