From patchwork Wed Sep 4 20:19:23 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Aleksa Sarai X-Patchwork-Id: 11131431 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B67F51395 for ; Wed, 4 Sep 2019 20:20:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A26E22087E for ; Wed, 4 Sep 2019 20:20:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730281AbfIDUUr (ORCPT ); Wed, 4 Sep 2019 16:20:47 -0400 Received: from mx2.mailbox.org ([80.241.60.215]:62092 "EHLO mx2.mailbox.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730214AbfIDUUq (ORCPT ); Wed, 4 Sep 2019 16:20:46 -0400 Received: from smtp2.mailbox.org (smtp2.mailbox.org [IPv6:2001:67c:2050:105:465:1:2:0]) (using TLSv1.2 with cipher ECDHE-RSA-CHACHA20-POLY1305 (256/256 bits)) (No client certificate requested) by mx2.mailbox.org (Postfix) with ESMTPS id 50DC1A1169; Wed, 4 Sep 2019 22:20:41 +0200 (CEST) X-Virus-Scanned: amavisd-new at heinlein-support.de Received: from smtp2.mailbox.org ([80.241.60.241]) by hefe.heinlein-support.de (hefe.heinlein-support.de [91.198.250.172]) (amavisd-new, port 10030) with ESMTP id NLDvBaFlidIu; Wed, 4 Sep 2019 22:20:38 +0200 (CEST) From: Aleksa Sarai To: Al Viro , Jeff Layton , "J. Bruce Fields" , Arnd Bergmann , David Howells , Shuah Khan , Shuah Khan , Ingo Molnar , Peter Zijlstra , Christian Brauner Cc: Aleksa Sarai , Eric Biederman , Andy Lutomirski , Andrew Morton , Alexei Starovoitov , Kees Cook , Jann Horn , Tycho Andersen , David Drysdale , Chanho Min , Oleg Nesterov , Rasmus Villemoes , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Aleksa Sarai , Linus Torvalds , containers@lists.linux-foundation.org, linux-alpha@vger.kernel.org, linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-xtensa@linux-xtensa.org, sparclinux@vger.kernel.org Subject: [PATCH v12 02/12] clone3: switch to copy_struct_from_user() Date: Thu, 5 Sep 2019 06:19:23 +1000 Message-Id: <20190904201933.10736-3-cyphar@cyphar.com> In-Reply-To: <20190904201933.10736-1-cyphar@cyphar.com> References: <20190904201933.10736-1-cyphar@cyphar.com> MIME-Version: 1.0 Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org The change is very straightforward, and takes advantage of the (very minor) efficiency improvements in copy_struct_from_user() -- that the memchr_inv() check is done on a buffer instead of one-at-at-time with get_user(). Additionally, explicitly define CLONE_ARGS_SIZE_VER0 to match the other users of the struct-extension pattern. Cc: Christian Brauner Signed-off-by: Aleksa Sarai --- include/uapi/linux/sched.h | 2 ++ kernel/fork.c | 34 ++++++---------------------------- 2 files changed, 8 insertions(+), 28 deletions(-) diff --git a/include/uapi/linux/sched.h b/include/uapi/linux/sched.h index b3105ac1381a..0945805982b4 100644 --- a/include/uapi/linux/sched.h +++ b/include/uapi/linux/sched.h @@ -47,6 +47,8 @@ struct clone_args { __aligned_u64 tls; }; +#define CLONE_ARGS_SIZE_VER0 64 /* sizeof first published struct */ + /* * Scheduling policies */ diff --git a/kernel/fork.c b/kernel/fork.c index 2852d0e76ea3..70c10d9b429a 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2528,39 +2528,17 @@ SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, #ifdef __ARCH_WANT_SYS_CLONE3 noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs, struct clone_args __user *uargs, - size_t size) + size_t usize) { + int err; struct clone_args args; - if (unlikely(size > PAGE_SIZE)) - return -E2BIG; - - if (unlikely(size < sizeof(struct clone_args))) + if (unlikely(usize < CLONE_ARGS_SIZE_VER0)) return -EINVAL; - if (unlikely(!access_ok(uargs, size))) - return -EFAULT; - - if (size > sizeof(struct clone_args)) { - unsigned char __user *addr; - unsigned char __user *end; - unsigned char val; - - addr = (void __user *)uargs + sizeof(struct clone_args); - end = (void __user *)uargs + size; - - for (; addr < end; addr++) { - if (get_user(val, addr)) - return -EFAULT; - if (val) - return -E2BIG; - } - - size = sizeof(struct clone_args); - } - - if (copy_from_user(&args, uargs, size)) - return -EFAULT; + err = copy_struct_from_user(&args, sizeof(args), uargs, usize); + if (err) + return err; *kargs = (struct kernel_clone_args){ .flags = args.flags,