linux-kernel - Re: [PATCH v3] f2fs: fix to do sanity check for inline inode

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Date:   Tue, 17 May 2022 10:28:08 +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, stable@...r.kernel.org,
        Ming Yan <yanming@....edu.cn>, Chao Yu <chao.yu@...o.com>
Subject: Re: [PATCH v3] f2fs: fix to do sanity check for inline inode

On 2022/5/17 8:46, Jaegeuk Kim wrote:
> On 05/15, Chao Yu wrote:
>> Yanming reported a kernel bug in Bugzilla kernel [1], which can be
>> reproduced. The bug message is:
>>
>> 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
>>
>> [1] https://bugzilla.kernel.org/show_bug.cgi?id=215895
>>
>> The bug is due to fuzzed inode has both inline_data and encrypted flags.
>> During f2fs_evict_inode(), as the inode was deleted by rename(), it
>> will cause inline data conversion due to conflicting flags. The page
>> cache will be polluted and the panic will be triggered in clear_inode().
>>
>> Try fixing the bug by doing 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>
>> ---
>> v3:
>> - clean up commit message suggested by Bagas Sanjaya.
>>   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;
> 
> Again, I prefer to check this in sanity_check_inode(), since we don't need to
> check all the time here.

Sure, how about adding a new parameter for f2fs_may_inline_data() to indicate
its caller is sanity_check_inode(), and do the checks here only for such path?

Thanks,

> 
>>   	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