Re: [PATCH] f2fs: fix to do sanity check for inline inode

Jaegeuk Kim
2022-05-13T21:07:50Z

On 04/28, Chao Yu wrote:
> 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@vger.kernel.org
> Reported-by: Ming Yan <yanming@tju.edu.cn>
> Signed-off-by: Chao Yu <chao.yu@oppo.com>
> ---
> fs/f2fs/f2fs.h | 7 +++++++
> fs/f2fs/inode.c | 3 +--
> 2 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 27aa93caec06..64c511b498cc 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -4173,6 +4173,13 @@ 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 (file_is_encrypt(inode) || file_is_verity(inode) ||
> + F2FS_I(inode)->i_flags & F2FS_COMPR_FL)
> + 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 83639238a1fe..234b8ed02644 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)) {

BTW, why can't we just check the above on-disk fields here only?

> 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);
> --
> 2.25.1