From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754243AbdJCMd2 (ORCPT ); Tue, 3 Oct 2017 08:33:28 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:34788 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754223AbdJCMdY (ORCPT ); Tue, 3 Oct 2017 08:33:24 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Al Viro Subject: [PATCH 4.13 087/110] fix infoleak in waitid(2) Date: Tue, 3 Oct 2017 14:29:49 +0200 Message-Id: <20171003114244.800849144@linuxfoundation.org> X-Mailer: git-send-email 2.14.2 In-Reply-To: <20171003114241.408583531@linuxfoundation.org> References: <20171003114241.408583531@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Al Viro commit 6c85501f2fabcfc4fc6ed976543d252c4eaf4be9 upstream. kernel_waitid() can return a PID, an error or 0. rusage is filled in the first case and waitid(2) rusage should've been copied out exactly in that case, *not* whenever kernel_waitid() has not returned an error. Compat variant shares that braino; none of kernel_wait4() callers do, so the below ought to fix it. Reported-and-tested-by: Alexander Potapenko Fixes: ce72a16fa705 ("wait4(2)/waitid(2): separate copying rusage to userland") Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman --- kernel/exit.c | 23 ++++++++++------------- 1 file changed, 10 insertions(+), 13 deletions(-) --- a/kernel/exit.c +++ b/kernel/exit.c @@ -1601,12 +1601,10 @@ SYSCALL_DEFINE5(waitid, int, which, pid_ struct waitid_info info = {.status = 0}; long err = kernel_waitid(which, upid, &info, options, ru ? &r : NULL); int signo = 0; + if (err > 0) { signo = SIGCHLD; err = 0; - } - - if (!err) { if (ru && copy_to_user(ru, &r, sizeof(struct rusage))) return -EFAULT; } @@ -1724,16 +1722,15 @@ COMPAT_SYSCALL_DEFINE5(waitid, if (err > 0) { signo = SIGCHLD; err = 0; - } - - if (!err && uru) { - /* kernel_waitid() overwrites everything in ru */ - if (COMPAT_USE_64BIT_TIME) - err = copy_to_user(uru, &ru, sizeof(ru)); - else - err = put_compat_rusage(&ru, uru); - if (err) - return -EFAULT; + if (uru) { + /* kernel_waitid() overwrites everything in ru */ + if (COMPAT_USE_64BIT_TIME) + err = copy_to_user(uru, &ru, sizeof(ru)); + else + err = put_compat_rusage(&ru, uru); + if (err) + return -EFAULT; + } } if (!infop)