From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754825AbdE0BKr (ORCPT ); Fri, 26 May 2017 21:10:47 -0400 Received: from mail-pf0-f175.google.com ([209.85.192.175]:36813 "EHLO mail-pf0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934508AbdEZUR4 (ORCPT ); Fri, 26 May 2017 16:17:56 -0400 From: Kees Cook To: kernel-hardening@lists.openwall.com Cc: Kees Cook , Laura Abbott , x86@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 01/20] NFS: Avoid cross-structure casting Date: Fri, 26 May 2017 13:17:05 -0700 Message-Id: <1495829844-69341-2-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1495829844-69341-1-git-send-email-keescook@chromium.org> References: <1495829844-69341-1-git-send-email-keescook@chromium.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When the call to nfs_devname() fails, the error path attempts to retain the error via the mnt variable, but this requires a cast across very different types (char * to struct vfsmount *), which the upcoming structure layout randomization plugin flags as being potentially dangerous in the face of randomization. This is a false positive, but what this code actually wants to do is retain the error value, so this patch explicitly sets it, instead of using what seems to be an unexpected cast. Signed-off-by: Kees Cook Acked-by: Trond Myklebust --- fs/nfs/namespace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c index 1a224a33a6c2..e5686be67be8 100644 --- a/fs/nfs/namespace.c +++ b/fs/nfs/namespace.c @@ -246,7 +246,7 @@ struct vfsmount *nfs_do_submount(struct dentry *dentry, struct nfs_fh *fh, devname = nfs_devname(dentry, page, PAGE_SIZE); if (IS_ERR(devname)) - mnt = (struct vfsmount *)devname; + mnt = ERR_CAST(devname); else mnt = nfs_do_clone_mount(NFS_SB(dentry->d_sb), devname, &mountdata); -- 2.7.4