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

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Date:   Sun, 25 Sep 2022 21:58:34 +0800
From:   Chao Yu <chao@...nel.org>
To:     Jaegeuk Kim <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

On 2022/9/23 2:11, Jaegeuk Kim wrote:
> I modified a bit.
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs.git/commit/?h=dev-test&id=a9a1592fa175baaaae43f54f175a972757c47919

Fine to me. :)

Thanks,

> 
> Thanks,
> 
> On 09/22, Chao Yu wrote:
>> 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)