From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8DC1BC433E9 for ; Wed, 17 Mar 2021 18:13:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5C6E464E31 for ; Wed, 17 Mar 2021 18:13:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232977AbhCQSN0 (ORCPT ); Wed, 17 Mar 2021 14:13:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:48102 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232932AbhCQSMv (ORCPT ); Wed, 17 Mar 2021 14:12:51 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B5DED64F40; Wed, 17 Mar 2021 18:12:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1616004770; bh=tAOWHqC9P/wCJfEc7pwTm0f6ZDZ3W3seZrEz5rIOACQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=D1AU1pJHHE2V6GJnv0oZiXQma+HCVhTPSEa1JU5j7KWFjzdp+hNqAw5P+moVYYuft y4NqpYtYluHyQqhnSVQiZgMrW34mLRObLbI9ixWUooSmvrtilrF5aJeMMA+LaDoIt0 c80GidzYk0mfIFN7MaNsuxFgmdmhgDvM5YpZLAdoxo5DIDPQsRcoFPkdMFUCVpuwkj 6Dao2J9YFfHbleJ8erzXAo2KhUADiEoPfvvBed9s2EnY23a7B0rOk/sTme1Z0hxoaw x2EXjht3DoowV84+WWg2dnZi0pT6Rc+k92+OHMYm2ALHkLHKiAHXfZyYYfvTI9v+cH bw493HEW/2FRQ== From: Andy Lutomirski To: x86@kernel.org Cc: LKML , Mark Rutland , Brian Gerst , Andy Lutomirski Subject: [PATCH v4 1/9] x86/dumpstack: Remove unnecessary range check fetching opcode bytes Date: Wed, 17 Mar 2021 11:12:40 -0700 Message-Id: <0a7892ea337e40d464ff291b264e40fbcd39f4af.1616004689.git.luto@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org copy_from_user_nmi() validates that the pointer is in the user range, so there is no need for an extra check in copy_code(). Signed-off-by: Andy Lutomirski --- arch/x86/kernel/dumpstack.c | 6 ------ 1 file changed, 6 deletions(-) diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index 299c20f0a38b..55cf3c8325c6 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -81,12 +81,6 @@ static int copy_code(struct pt_regs *regs, u8 *buf, unsigned long src, /* The user space code from other tasks cannot be accessed. */ if (regs != task_pt_regs(current)) return -EPERM; - /* - * Make sure userspace isn't trying to trick us into dumping kernel - * memory by pointing the userspace instruction pointer at it. - */ - if (__chk_range_not_ok(src, nbytes, TASK_SIZE_MAX)) - return -EINVAL; /* * Even if named copy_from_user_nmi() this can be invoked from -- 2.30.2