From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:35622 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933223AbdERNRx (ORCPT ); Thu, 18 May 2017 09:17:53 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kees Cook , Vlastimil Babka , Michal Hocko , Andrew Morton , Linus Torvalds Subject: [PATCH 3.18 18/49] fs/xattr.c: zero out memory copied to userspace in getxattr Date: Thu, 18 May 2017 15:16:27 +0200 Message-Id: <20170518131643.799316958@linuxfoundation.org> In-Reply-To: <20170518131643.028057293@linuxfoundation.org> References: <20170518131643.028057293@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michal Hocko commit 81be3dee96346fbe08c31be5ef74f03f6b63cf68 upstream. getxattr uses vmalloc to allocate memory if kzalloc fails. This is filled by vfs_getxattr and then copied to the userspace. vmalloc, however, doesn't zero out the memory so if the specific implementation of the xattr handler is sloppy we can theoretically expose a kernel memory. There is no real sign this is really the case but let's make sure this will not happen and use vzalloc instead. Fixes: 779302e67835 ("fs/xattr.c:getxattr(): improve handling of allocation failures") Link: http://lkml.kernel.org/r/20170306103327.2766-1-mhocko@kernel.org Acked-by: Kees Cook Reported-by: Vlastimil Babka Signed-off-by: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/xattr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/xattr.c +++ b/fs/xattr.c @@ -444,7 +444,7 @@ getxattr(struct dentry *d, const char __ size = XATTR_SIZE_MAX; kvalue = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); if (!kvalue) { - vvalue = vmalloc(size); + vvalue = vzalloc(size); if (!vvalue) return -ENOMEM; kvalue = vvalue;