linux-kernel - Re: [PATCH v3] f2fs: fix to detect corrupted meta ino

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Date:   Thu, 22 Sep 2022 09:54:16 +0800
From:   Chao Yu <chao@...nel.org>
To:     jaegeuk@...nel.org
Cc:     linux-f2fs-devel@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] f2fs: fix to detect corrupted meta ino

Ping,

On 2022/9/13 15:48, Chao Yu wrote:
> It is possible that ino of dirent or orphan inode is corrupted in a
> fuzzed image, occasionally, if corrupted ino is equal to meta ino:
> meta_ino, node_ino or compress_ino, caller of f2fs_iget() from below
> call paths will get meta inode directly, it's not allowed, let's
> add sanity check to detect such cases.
> 
> case #1
> - recover_dentry
>   - __f2fs_find_entry
>   - f2fs_iget_retry
> 
> case #2
> - recover_orphan_inode
>   - f2fs_iget_retry
> 
> Signed-off-by: Chao Yu <chao@...nel.org>
> ---
> v3:
> - update commit title/message
> - change logic inside f2fs_iget() rather than its caller
>   fs/f2fs/inode.c | 25 ++++++++++++++++++-------
>   1 file changed, 18 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> index cde0a3dc80c3..1baac6056733 100644
> --- a/fs/f2fs/inode.c
> +++ b/fs/f2fs/inode.c
> @@ -487,6 +487,12 @@ static int do_read_inode(struct inode *inode)
>   	return 0;
>   }
>   
> +static bool is_meta_ino(struct f2fs_sb_info *sbi, unsigned int ino)
> +{
> +	return ino == F2FS_NODE_INO(sbi) || ino == F2FS_META_INO(sbi) ||
> +		ino == F2FS_COMPRESS_INO(sbi);
> +}
> +
>   struct inode *f2fs_iget(struct super_block *sb, unsigned long ino)
>   {
>   	struct f2fs_sb_info *sbi = F2FS_SB(sb);
> @@ -497,17 +503,22 @@ struct inode *f2fs_iget(struct super_block *sb, unsigned long ino)
>   	if (!inode)
>   		return ERR_PTR(-ENOMEM);
>   
> +	if (is_meta_ino(sbi, ino)) {
> +		if (!(inode->i_state & I_NEW)) {
> +			f2fs_err(sbi, "detect corrupted inode no:%lu, run fsck to repair", ino);
> +			set_sbi_flag(sbi, SBI_NEED_FSCK);
> +			ret = -EFSCORRUPTED;
> +			trace_f2fs_iget_exit(inode, ret);
> +			iput(inode);
> +			return ERR_PTR(ret);
> +		}
> +		goto make_now;
> +	}
> +
>   	if (!(inode->i_state & I_NEW)) {
>   		trace_f2fs_iget(inode);
>   		return inode;
>   	}
> -	if (ino == F2FS_NODE_INO(sbi) || ino == F2FS_META_INO(sbi))
> -		goto make_now;
> -
> -#ifdef CONFIG_F2FS_FS_COMPRESSION
> -	if (ino == F2FS_COMPRESS_INO(sbi))
> -		goto make_now;
> -#endif
>   
>   	ret = do_read_inode(inode);
>   	if (ret)