2016-12-13 18:48:50

by Cong Wang

Subject: [Patch] 9p: fix a potential acl leak

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 <[email protected]>
Reviewed-by: Jan Kara <[email protected]>
Cc: Eric Van Hensbergen <[email protected]>
Cc: Ron Minnich <[email protected]>
Cc: Latchesar Ionkov <[email protected]>
Signed-off-by: Cong Wang <[email protected]>
---
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;
}
--
2.5.5

2016-12-14 13:44:19

by Greg Kurz

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

On Tue, 13 Dec 2016 10:33:34 -0800
Cong Wang <[email protected]> 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 <[email protected]>
> Reviewed-by: Jan Kara <[email protected]>
> Cc: Eric Van Hensbergen <[email protected]>
> Cc: Ron Minnich <[email protected]>
> Cc: Latchesar Ionkov <[email protected]>
> Signed-off-by: Cong Wang <[email protected]>
> ---

Reviewed-by: Greg Kurz <[email protected]>

> 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;
> }