linux-kernel - Re: [EXTERNAL] [PATCH 5.4 303/309] cifs: fix mode bits from dir listing when mounted with modefromsid

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Date:   Mon, 10 Feb 2020 11:17:57 -0800
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Pavel Shilovskiy <pshilov@...rosoft.com>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>,
        Aurelien Aptel <aaptel@...e.com>,
        Steven French <Steven.French@...rosoft.com>
Subject: Re: [EXTERNAL] [PATCH 5.4 303/309] cifs: fix mode bits from dir
 listing when mounted with modefromsid

On Mon, Feb 10, 2020 at 07:10:00PM +0000, Pavel Shilovskiy wrote:
> 
> -----Original Message Begin-----
> From: Greg Kroah-Hartman <gregkh@...uxfoundation.org> 
> Sent: Monday, February 10, 2020 4:34 AM
> To: linux-kernel@...r.kernel.org
> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>; stable@...r.kernel.org; Aurelien Aptel <aaptel@...e.com>; Steven French <Steven.French@...rosoft.com>; Pavel Shilovskiy <pshilov@...rosoft.com>
> Subject: [EXTERNAL] [PATCH 5.4 303/309] cifs: fix mode bits from dir listing when mounted with modefromsid
> 
> From: Aurelien Aptel <aaptel@...e.com>
> 
> commit e3e056c35108661e418c803adfc054bf683426e7 upstream.
> 
> When mounting with -o modefromsid, the mode bits are stored in an ACE. Directory enumeration (e.g. ls -l /mnt) triggers an SMB Query Dir which does not include ACEs in its response. The mode bits in this case are silently set to a default value of 755 instead.
> 
> This patch marks the dentry created during the directory enumeration as needing re-evaluation (i.e. additional Query Info with ACEs) so that the mode bits can be properly extracted.
> 
> Quick repro:
> 
> $ mount.cifs //win19.test/data /mnt -o ...,modefromsid $ touch /mnt/foo && chmod 751 /mnt/foo $ stat /mnt/foo
>   # reports 751 (OK)
> $ sleep 2
>   # dentry older than 1s by default get invalidated $ ls -l /mnt
>   # since dentry invalid, ls does a Query Dir
>   # and reports foo as 755 (WRONG)
> 
> Signed-off-by: Aurelien Aptel <aaptel@...e.com>
> Signed-off-by: Steve French <stfrench@...rosoft.com>
> CC: Stable <stable@...r.kernel.org>
> Reviewed-by: Pavel Shilovsky <pshilov@...rosoft.com>
> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> 
> ---
>  fs/cifs/readdir.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> --- a/fs/cifs/readdir.c
> +++ b/fs/cifs/readdir.c
> @@ -174,7 +174,8 @@ cifs_fill_common_info(struct cifs_fattr
>  	 * may look wrong since the inodes may not have timed out by the time
>  	 * "ls" does a stat() call on them.
>  	 */
> -	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL)
> +	if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL) ||
> +	    (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MODE_FROM_SID))
>  		fattr->cf_flags |= CIFS_FATTR_NEED_REVAL;
>  
>  	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL &&
> 
> -----Original Message End-----
> 
> Hi Greg,
> 
> This patch fixes the following commit that was introduced in v5.5:
> 
> commit fdef665ba44ad5ed154af2acfb19ae2ee3bf5dcc
> Author: Steve French <stfrench@...rosoft.com>
> Date:   Fri Dec 6 02:02:38 2019 -0600
> 
>     smb3: fix mode passed in on create for modetosid mount option
> 
> 
> Please remove the patch from all stable trees expect 5.5.y.

Now dropped, thanks for letting me know.

greg k-h