[PATCH resend] 9p: fix a potential acl leak

From: Cong Wang
Date: Thu Feb 09 2017 - 17:44:26 EST


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>
Reviewed-by: Greg Kurz <groug@xxxxxxxx>
Cc: Eric Van Hensbergen <ericvh@xxxxxxxxx>
Cc: Ron Minnich <rminnich@xxxxxxxxxx>
Cc: Latchesar Ionkov <lucho@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx>
---
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