From: <gregkh@linuxfoundation.org>
To: richard@nod.at, gregkh@linuxfoundation.org,
keescook@chromium.org, mszeredi@redhat.com
Cc: <stable@vger.kernel.org>, <stable-commits@vger.kernel.org>
Subject: Patch "ovl: Fix info leak in ovl_lookup_temp()" has been added to the 4.8-stable tree
Date: Wed, 26 Oct 2016 10:16:21 +0200 [thread overview]
Message-ID: <147746978165239@kroah.com> (raw)
This is a note to let you know that I've just added the patch titled
ovl: Fix info leak in ovl_lookup_temp()
to the 4.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ovl-fix-info-leak-in-ovl_lookup_temp.patch
and it can be found in the queue-4.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.
>From 6a45b3628ce4dcf7498b39c87d475bab6e2a9b24 Mon Sep 17 00:00:00 2001
From: Richard Weinberger <richard@nod.at>
Date: Fri, 16 Sep 2016 11:45:24 +0200
Subject: ovl: Fix info leak in ovl_lookup_temp()
From: Richard Weinberger <richard@nod.at>
commit 6a45b3628ce4dcf7498b39c87d475bab6e2a9b24 upstream.
The function uses the memory address of a struct dentry as unique id.
While the address-based directory entry is only visible to root it is IMHO
still worth fixing since the temporary name does not have to be a kernel
address. It can be any unique number. Replace it by an atomic integer
which is allowed to wrap around.
Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Fixes: e9be9d5e76e3 ("overlay filesystem")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/overlayfs/dir.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -14,6 +14,7 @@
#include <linux/cred.h>
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>
+#include <linux/atomic.h>
#include "overlayfs.h"
void ovl_cleanup(struct inode *wdir, struct dentry *wdentry)
@@ -37,8 +38,10 @@ struct dentry *ovl_lookup_temp(struct de
{
struct dentry *temp;
char name[20];
+ static atomic_t temp_id = ATOMIC_INIT(0);
- snprintf(name, sizeof(name), "#%lx", (unsigned long) dentry);
+ /* counter is allowed to wrap, since temp dentries are ephemeral */
+ snprintf(name, sizeof(name), "#%x", atomic_inc_return(&temp_id));
temp = lookup_one_len(name, workdir, strlen(name));
if (!IS_ERR(temp) && temp->d_inode) {
Patches currently in stable-queue which might be from richard@nod.at are
queue-4.8/ubi-deal-with-interrupted-erasures-in-wl.patch
queue-4.8/ovl-fix-info-leak-in-ovl_lookup_temp.patch
reply other threads:[~2016-10-26 8:17 UTC|newest]
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