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=-10.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, T_DKIMWL_WL_MED,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 EE9CEC433F4 for ; Mon, 27 Aug 2018 18:58:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A2CC0208B9 for ; Mon, 27 Aug 2018 18:58:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="Inp3rDYf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A2CC0208B9 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727838AbeH0WqC (ORCPT ); Mon, 27 Aug 2018 18:46:02 -0400 Received: from mail-vk0-f74.google.com ([209.85.213.74]:35250 "EHLO mail-vk0-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727479AbeH0WqC (ORCPT ); Mon, 27 Aug 2018 18:46:02 -0400 Received: by mail-vk0-f74.google.com with SMTP id x125-v6so15019vke.2 for ; Mon, 27 Aug 2018 11:58:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=ycFD50Qbqy2nsG8VK8f/Mv9TVDy1OUIkLU31FaF+unc=; b=Inp3rDYfU183FlYE+NFUsy7ksvex6gl9N2We90XZsfgqClFLoFcriIVQcXEyyfEeZF WxFcaVIghxRt5djJfm3wc5G1w1KItP+zoql6wI+Rve/EEkf0bASuUvgGlPsVwrmDqa3c oNfZ4udfPhnb5FVZnP/tUIzGyQWIjre3LHDdkywsMGLYpdtmnJyqjd52VeI8L+i5ZpzW zfh8tsFrPRRCjm9a3zgXSqSVAajVT/wjOpaWjzYfa/tjiRllc4sMW3mdAI15jVQVXazM mIS8BU0Wto84H+0aZ3N1mgg/rWCQr10Xf/dvjKAwnd4oXMi/Qkd8XgmI9rI6BX6SqX+m qleQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=ycFD50Qbqy2nsG8VK8f/Mv9TVDy1OUIkLU31FaF+unc=; b=qlnbj5r1113KED7VXBxplHZfV/HcH8rXta1p5SY/gsJQ90O+OWj5sF7aWiW8zlthJs jgdO061OK/V7Ll38P6xQSxRBC8Y01D5tQ3JZ8mv8BMdilcrFjiauYpsdj08bZEqz3yxw JbXVdHOL9oF8DT+iQUWkdtK2BysWUZnCzZHPUTzCH6We1PA3N01LToZ1OgV/Hb5VmyKy K9HXy4ztM+GGy41Sf8Wvja3pfQUDp7k0S5r7g4kfUNil1kQnTymTjNYsSnP0PZnZVKzu LtbxQ5Rl7FVYK9EULvLTqMq3dKDa4mzFxmLrAAc1n4gLZqAXaokPJ5rRv4qOMkLNZrrq 0HSw== X-Gm-Message-State: APzg51B5eBKZnnrFjNoSIliOZM51HJ7IZlTUvGyjLhCbb84MyDSUTbX8 B2/p04Hhj5xuSmSaNYRzh4I3qpo2RQ== X-Google-Smtp-Source: ANB0VdaXjqOrrHANxz1rCv+tH9fays7AA2RAsMOahiQ8j6ctktmJS29FhFIfemOGyGe8R5FsvzGjCzFPjA== X-Received: by 2002:a1f:a991:: with SMTP id s139-v6mr6956921vke.107.1535396292059; Mon, 27 Aug 2018 11:58:12 -0700 (PDT) Date: Mon, 27 Aug 2018 20:56:31 +0200 In-Reply-To: <20180827185631.163506-1-jannh@google.com> Message-Id: <20180827185631.163506-8-jannh@google.com> Mime-Version: 1.0 References: <20180827185631.163506-1-jannh@google.com> X-Mailer: git-send-email 2.19.0.rc0.228.g281dcd1b4d0-goog Subject: [PATCH v2 7/7] lkdtm: test copy_to_user() on bad kernel pointer under KERNEL_DS From: Jann Horn To: Kees Cook , Thomas Gleixner , Ingo Molnar , x86@kernel.org, Andy Lutomirski , kernel-hardening@lists.openwall.com, Tony Luck , Borislav Petkov , jannh@google.com Cc: linux-kernel@vger.kernel.org, dvyukov@google.com, linux-edac@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Test whether the kernel WARN()s when, under KERNEL_DS, a bad kernel pointer is used as "userspace" pointer. Should normally be used in "DIRECT" mode. Signed-off-by: Jann Horn --- drivers/misc/lkdtm/core.c | 1 + drivers/misc/lkdtm/lkdtm.h | 1 + drivers/misc/lkdtm/usercopy.c | 13 +++++++++++++ 3 files changed, 15 insertions(+) diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c index 2154d1bfd18b..5a755590d3dc 100644 --- a/drivers/misc/lkdtm/core.c +++ b/drivers/misc/lkdtm/core.c @@ -183,6 +183,7 @@ static const struct crashtype crashtypes[] = { CRASHTYPE(USERCOPY_STACK_FRAME_FROM), CRASHTYPE(USERCOPY_STACK_BEYOND), CRASHTYPE(USERCOPY_KERNEL), + CRASHTYPE(USERCOPY_KERNEL_DS), }; diff --git a/drivers/misc/lkdtm/lkdtm.h b/drivers/misc/lkdtm/lkdtm.h index 9e513dcfd809..07db641d71d0 100644 --- a/drivers/misc/lkdtm/lkdtm.h +++ b/drivers/misc/lkdtm/lkdtm.h @@ -82,5 +82,6 @@ void lkdtm_USERCOPY_STACK_FRAME_TO(void); void lkdtm_USERCOPY_STACK_FRAME_FROM(void); void lkdtm_USERCOPY_STACK_BEYOND(void); void lkdtm_USERCOPY_KERNEL(void); +void lkdtm_USERCOPY_KERNEL_DS(void); #endif diff --git a/drivers/misc/lkdtm/usercopy.c b/drivers/misc/lkdtm/usercopy.c index 9725aed305bb..389475b25bb7 100644 --- a/drivers/misc/lkdtm/usercopy.c +++ b/drivers/misc/lkdtm/usercopy.c @@ -322,6 +322,19 @@ void lkdtm_USERCOPY_KERNEL(void) vm_munmap(user_addr, PAGE_SIZE); } +void lkdtm_USERCOPY_KERNEL_DS(void) +{ + char __user *user_ptr = (char __user *)ERR_PTR(-EINVAL); + mm_segment_t old_fs = get_fs(); + char buf[10] = {0}; + + pr_info("attempting copy_to_user on unmapped kernel address\n"); + set_fs(KERNEL_DS); + if (copy_to_user(user_ptr, buf, sizeof(buf))) + pr_info("copy_to_user un unmapped kernel address failed\n"); + set_fs(old_fs); +} + void __init lkdtm_usercopy_init(void) { /* Prepare cache that lacks SLAB_USERCOPY flag. */ -- 2.19.0.rc0.228.g281dcd1b4d0-goog