linux-ext4 - Re: [PATCH] ext2: compare old and new mode before setting update

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 21 Nov 2018 18:55:28 +0800
From:   cgxu519 <cgxu519@....com>
To:     Jan Kara <jack@...e.cz>
Cc:     jack@...e.com, linux-ext4@...r.kernel.org
Subject: Re: [PATCH] ext2: compare old and new mode before setting update_mode
 flag

On 11/19/18 6:04 PM, Jan Kara wrote:
> On Sat 17-11-18 17:01:00, Chengguang Xu wrote:
>> If new mode is the same as old mode we don't have to reset
>> inode mode in the rest of the code, so compare old and new
>> mode before setting update_mode flag.
>>
>> Signed-off-by: Chengguang Xu <cgxu519@....com>
> I don't think this is quite correct. E.g. I would think that i_ctime should
> be updated even if the effective mode resulting from acl did not change.

I think  __ext2_set_acl() will probably update i_ctime in this case, am 
I missing something?

Thanks,


> ---
>   fs/ext2/acl.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ext2/acl.c b/fs/ext2/acl.c
> index cf4c77f8dd08..f4dd728393c8 100644
> --- a/fs/ext2/acl.c
> +++ b/fs/ext2/acl.c
> @@ -226,7 +226,8 @@ ext2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
>   		error = posix_acl_update_mode(inode, &mode, &acl);
>   		if (error)
>   			return error;
> -		update_mode = 1;
> +		if (mode != inode->i_mode)
> +			update_mode = 1;
>   	}
>   	error = __ext2_set_acl(inode, acl, type);
>   	if (!error && update_mode) {
> -- 
> 2.17.2
>
>