From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:48480 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S941144AbcJZIRp (ORCPT ); Wed, 26 Oct 2016 04:17:45 -0400 Subject: Patch "ovl: Fix info leak in ovl_lookup_temp()" has been added to the 4.8-stable tree To: richard@nod.at, gregkh@linuxfoundation.org, keescook@chromium.org, mszeredi@redhat.com Cc: , From: Date: Wed, 26 Oct 2016 10:16:21 +0200 Message-ID: <147746978165239@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 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 know about it. >>From 6a45b3628ce4dcf7498b39c87d475bab6e2a9b24 Mon Sep 17 00:00:00 2001 From: Richard Weinberger Date: Fri, 16 Sep 2016 11:45:24 +0200 Subject: ovl: Fix info leak in ovl_lookup_temp() From: Richard Weinberger 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 Reviewed-by: Kees Cook Signed-off-by: Miklos Szeredi Fixes: e9be9d5e76e3 ("overlay filesystem") Signed-off-by: Greg Kroah-Hartman --- 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 #include #include +#include #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