lkml.org 
[lkml]   [2016]   [Dec]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: CVE-2016-7097 causes acl leak
From
Date
On 12/12/2016 10:26 PM, Cong Wang wrote:
> On Mon, Dec 12, 2016 at 4:26 PM, Mark Salyzyn <salyzyn@android.com> wrote:
>> The leaks were introduced in 9p, gfs2, jfs and xfs drivers only.
>
> Only the 9p case is obvious to me:
>
> 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;
> }
>
>
> The rest are anti-pattern (modifying parameters on stack via address)
> but look correct.

Greg KH: Beware that this similar fix needs to be applied to _backports_
to stable kernel trees on other filesystem driver that have the same
pattern (with local posix_acl_release(acl) calls). I have found that
depending on vintage these would include this driver 9p, and possibly
gfs2, jfs and xfs. Be aware.


Sincerely -- Mark Salyzyn

\
 
 \ /
  Last update: 2016-12-14 00:44    [W:0.124 / U:2.948 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site