From patchwork Fri May 29 23:28:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Al Viro X-Patchwork-Id: 1301081 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=ZenIV.linux.org.uk Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 49Ygjw3rZ7z9sSF for ; Sat, 30 May 2020 09:28:36 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728733AbgE2X2R (ORCPT ); Fri, 29 May 2020 19:28:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40020 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728738AbgE2X2Q (ORCPT ); Fri, 29 May 2020 19:28:16 -0400 Received: from ZenIV.linux.org.uk (zeniv.linux.org.uk [IPv6:2002:c35c:fd02::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 104E7C08C5CB; Fri, 29 May 2020 16:28:16 -0700 (PDT) Received: from viro by ZenIV.linux.org.uk with local (Exim 4.93 #3 (Red Hat Linux)) id 1jeoQA-000Bks-2G; Fri, 29 May 2020 23:28:14 +0000 From: Al Viro To: Linus Torvalds Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Alexei Starovoitov , bpf@vger.kernel.org Subject: [PATCH 9/9] bpf: make bpf_check_uarg_tail_zero() use check_zeroed_user() Date: Sat, 30 May 2020 00:28:14 +0100 Message-Id: <20200529232814.45149-1-viro@ZenIV.linux.org.uk> X-Mailer: git-send-email 2.25.4 In-Reply-To: <20200528234025.GT23230@ZenIV.linux.org.uk> References: <20200528234025.GT23230@ZenIV.linux.org.uk> MIME-Version: 1.0 Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org From: Al Viro ... rather than open-coding it, and badly, at that. Signed-off-by: Al Viro Acked-by: Alexei Starovoitov --- kernel/bpf/syscall.c | 25 ++++++------------------- 1 file changed, 6 insertions(+), 19 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 64783da34202..41ba746ecbc2 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -67,32 +67,19 @@ int bpf_check_uarg_tail_zero(void __user *uaddr, size_t expected_size, size_t actual_size) { - unsigned char __user *addr; - unsigned char __user *end; - unsigned char val; - int err; + unsigned char __user *addr = uaddr + expected_size; + int res; if (unlikely(actual_size > PAGE_SIZE)) /* silly large */ return -E2BIG; - if (unlikely(!access_ok(uaddr, actual_size))) - return -EFAULT; - if (actual_size <= expected_size) return 0; - addr = uaddr + expected_size; - end = uaddr + actual_size; - - for (; addr < end; addr++) { - err = get_user(val, addr); - if (err) - return err; - if (val) - return -E2BIG; - } - - return 0; + res = check_zeroed_user(addr, actual_size - expected_size); + if (res < 0) + return res; + return res ? 0 : -E2BIG; } const struct bpf_map_ops bpf_map_offload_ops = {