On Thu, Jun 22, 2017 at 3:31 PM, Jan Kara <jack@xxxxxxx> 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@xxxxxxxxxxxxxxx
> CC: linux-ext4@xxxxxxxxxxxxxxx
> CC: "Theodore Ts'o" <tytso@xxxxxxx>
> Signed-off-by: Jan Kara <jack@xxxxxxx>
This is looking good, thanks.
Reviewed-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
> ---
> 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
>