Re: CVE-2016-7097 causes acl leak

[Cong Wang]

On Mon, Dec 12, 2016 at 4:26 PM, Mark Salyzyn <salyzyn@xxxxxxxxxxx> 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.