Re: [V9fs-developer] [Patch] 9p: fix a potential acl leak

[Greg Kurz]

On Tue, 13 Dec 2016 10:33:34 -0800
Cong Wang <xiyou.wangcong@xxxxxxxxx> wrote:

> posix_acl_update_mode() could possibly clear 'acl', if so
> we leak the memory pointed by 'acl'. Save this pointer
> before calling posix_acl_update_mode() and release the memory
> if 'acl' really gets cleared.
> 
> Reported-by: Mark Salyzyn <salyzyn@xxxxxxxxxxx>
> Reviewed-by: Jan Kara <jack@xxxxxxx>
> Cc: Eric Van Hensbergen <ericvh@xxxxxxxxx>
> Cc: Ron Minnich <rminnich@xxxxxxxxxx>
> Cc: Latchesar Ionkov <lucho@xxxxxxxxxx>
> Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx>
> ---

Reviewed-by: Greg Kurz <groug@xxxxxxxx>

>  fs/9p/acl.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/fs/9p/acl.c b/fs/9p/acl.c
> index b3c2cc7..082d227 100644
> --- a/fs/9p/acl.c
> +++ b/fs/9p/acl.c
> @@ -277,6 +277,7 @@ static int v9fs_xattr_set_acl(const struct xattr_handler *handler,
>  	case ACL_TYPE_ACCESS:
>  		if (acl) {
>  			struct iattr iattr;
> +			struct posix_acl *old_acl = acl;
>  
>  			retval = posix_acl_update_mode(inode, &iattr.ia_mode, &acl);
>  			if (retval)
> @@ -287,6 +288,7 @@ static int v9fs_xattr_set_acl(const struct xattr_handler *handler,
>  				 * by the mode bits. So don't
>  				 * update ACL.
>  				 */
> +				posix_acl_release(old_acl);
>  				value = NULL;
>  				size = 0;
>  			}