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=-10.5 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 AEEFFC433F4 for ; Tue, 28 Aug 2018 20:15:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 68FF32087E for ; Tue, 28 Aug 2018 20:15:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="dJtCuA9+" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 68FF32087E 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 S1727502AbeH2AIS (ORCPT ); Tue, 28 Aug 2018 20:08:18 -0400 Received: from mail-qk0-f201.google.com ([209.85.220.201]:40286 "EHLO mail-qk0-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727480AbeH2AIR (ORCPT ); Tue, 28 Aug 2018 20:08:17 -0400 Received: by mail-qk0-f201.google.com with SMTP id 93-v6so2329884qkq.7 for ; Tue, 28 Aug 2018 13:15:02 -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=orkRpEOZI7lmcFqEOmIoRKnoNlpBSRaZPpEarFrxgn4=; b=dJtCuA9+jn3JAd7mRLBblEhQcu5ltG2x2ErJEb4AoFY6cAWBnnE9WrZUPagGV6lPS/ Isk7kxKGsTe7qKU5K8pvQBCTBKDgZ5XoD3YU07b3hcWTCY5X5sEHOgV55KbG9jvGeTR8 eNHoOcCNYhBrWY/AzOpz4S2FKOl5BFe2si0NqeWAuKLgg2t1/uK6xcvm6cfM6qBRP/1f B4mD/dy3Wxaa+EQA1v7Aan4ChgCArgOPGqmYLQWLUGrAkmZzY5klGbh6hqRbqutOWXQC ASj6uLgwRB23No3sHnOnXZRBTtHtxRjU4kG0N149tX+0ldcEBocZhrYIDAaMne6Nup0M 8phw== 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=orkRpEOZI7lmcFqEOmIoRKnoNlpBSRaZPpEarFrxgn4=; b=C55qODRbuX43/3oYsEJLbaK5OLSr+sRAcrk4OJp5Se5rm9Ysjr77qAdNsA7Wejhfil wnRziJtvBt234lw665IVxjaVoRPFP5AAOZSRRDGD0XnqulngDpZGE3RoKtEzUhSs/9gE 7C2Df3o92XYCN5jgCzzZg43B5R/VzSdwoO1a8x7WMIx4WTuvnbsJ+7gd4jGMjduy+ByA 9LX/QCrgy01ozRoPfyioRuGvfi0S5PPW+xjW+ceI62fwptMKz7hXfxG4GJoHcmRmgzYN ltJdfjyNFZGsTkrXok2WwjZeqL8bmXdI09kOlI4tmnbGrtTp/RsVbeTn7eE3c5fZVfBf DAGg== X-Gm-Message-State: APzg51BCd0k9cl9MONm75xuq7qjF9yEY4qIzSIPGzAoSvBUybWhp0nUk WlGUVajZyHnT4ghrxYOC4VXy+2wN/Q== X-Google-Smtp-Source: ANB0VdZBbCL7UFF1k+aW0ff9wf579S1iabnTvek8YhkrSkZNOC1Y6bJfoziFPHprHIkWIEL+QMDgVZmdfg== X-Received: by 2002:a0c:c3cd:: with SMTP id p13-v6mr1692849qvi.22.1535487301486; Tue, 28 Aug 2018 13:15:01 -0700 (PDT) Date: Tue, 28 Aug 2018 22:14:21 +0200 In-Reply-To: <20180828201421.157735-1-jannh@google.com> Message-Id: <20180828201421.157735-8-jannh@google.com> Mime-Version: 1.0 References: <20180828201421.157735-1-jannh@google.com> X-Mailer: git-send-email 2.19.0.rc0.228.g281dcd1b4d0-goog Subject: [PATCH v3 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, jannh@google.com Cc: linux-kernel@vger.kernel.org, dvyukov@google.com, Masami Hiramatsu , "Naveen N. Rao" , Anil S Keshavamurthy , "David S. Miller" , Alexander Viro , linux-fsdevel@vger.kernel.org, Borislav Petkov 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. Acked-by: Kees Cook 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