linux-ext4 - Re: [PATCH 01/11] ext4: Don't clear SGID when inheriting ACLs

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Message-ID: <20170718161631.GA27293@quack2.suse.cz>
Date:   Tue, 18 Jul 2017 18:16:31 +0200
From:   Jan Kara <jack@...e.cz>
To:     linux-fsdevel@...r.kernel.org
Cc:     Andreas Gruenbacher <agruenba@...hat.com>, Jan Kara <jack@...e.cz>,
        linux-ext4@...r.kernel.org, Theodore Ts'o <tytso@....edu>
Subject: Re: [PATCH 01/11] ext4: Don't clear SGID when inheriting ACLs

On Thu 22-06-17 15:31:05, Jan Kara wrote:
> When new directory 'DIR1' is created in a directory 'DIR0' with SGID bit
> set, DIR1 is expected to have SGID bit set (and owning group equal to
> the owning group of 'DIR0'). However when 'DIR0' also has some default
> ACLs that 'DIR1' inherits, setting these ACLs will result in SGID bit on
> 'DIR1' to get cleared if user is not member of the owning group.
> 
> Fix the problem by moving posix_acl_update_mode() out of
> __ext4_set_acl() into ext4_set_acl(). That way the function will not be
> called when inheriting ACLs which is what we want as it prevents SGID
> bit clearing and the mode has been properly set by posix_acl_create()
> anyway.
> 
> Fixes: 073931017b49d9458aa351605b43a7e34598caef
> CC: stable@...r.kernel.org
> CC: linux-ext4@...r.kernel.org
> CC: "Theodore Ts'o" <tytso@....edu>
> Signed-off-by: Jan Kara <jack@...e.cz>

Ted, can you please pick up this fix? Thanks!

								Honza
> ---
>  fs/ext4/acl.c | 16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/ext4/acl.c b/fs/ext4/acl.c
> index 3ec0e46de95f..37242af33ff2 100644
> --- a/fs/ext4/acl.c
> +++ b/fs/ext4/acl.c
> @@ -193,13 +193,6 @@ __ext4_set_acl(handle_t *handle, struct inode *inode, int type,
>  	switch (type) {
>  	case ACL_TYPE_ACCESS:
>  		name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
> -		if (acl) {
> -			error = posix_acl_update_mode(inode, &inode->i_mode, &acl);
> -			if (error)
> -				return error;
> -			inode->i_ctime = current_time(inode);
> -			ext4_mark_inode_dirty(handle, inode);
> -		}
>  		break;
>  
>  	case ACL_TYPE_DEFAULT:
> @@ -242,7 +235,16 @@ ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
>  	if (IS_ERR(handle))
>  		return PTR_ERR(handle);
>  
> +	if (type == ACL_TYPE_ACCESS && acl) {
> +		error = posix_acl_update_mode(inode, &inode->i_mode, &acl);
> +		if (error)
> +			goto out_stop;
> +		inode->i_ctime = current_time(inode);
> +		ext4_mark_inode_dirty(handle, inode);
> +	}
> +
>  	error = __ext4_set_acl(handle, inode, type, acl);
> +out_stop:
>  	ext4_journal_stop(handle);
>  	if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
>  		goto retry;
> -- 
> 2.12.3
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR