From patchwork Thu Apr 1 23:32:08 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 12179963 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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 386D8C43460 for ; Thu, 1 Apr 2021 23:33:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1B904610F7 for ; Thu, 1 Apr 2021 23:33:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236415AbhDAXdT (ORCPT ); Thu, 1 Apr 2021 19:33:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50136 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236238AbhDAXdB (ORCPT ); Thu, 1 Apr 2021 19:33:01 -0400 Received: from mail-qk1-x749.google.com (mail-qk1-x749.google.com [IPv6:2607:f8b0:4864:20::749]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4C5FAC0611A2 for ; Thu, 1 Apr 2021 16:32:40 -0700 (PDT) Received: by mail-qk1-x749.google.com with SMTP id x11so4755875qki.22 for ; Thu, 01 Apr 2021 16:32:40 -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=ihXC2HiiYMKXSpC6M6Il6sHAA7ZrY8nJsA58n/MMk7w=; b=SUsTTUFBC5XLjQ0kmj8Tomq7Zqx0Hb4Il6WGzaLjEgbPEKek7Gt1me/9rrPDrJbPoB 6L1gXdtEKIn2CaQiuuMwYHqPbPbF0YPAF8fn25t4Ahhl3F8CvP41+aSphFCMmkLjRpWg 7K0837iEZV3dQwTL7t1gAd8fykHHRmRjN8S97mvJc83fQtkRf21ag0uG3eFsXsOk3Yd6 WfTbU1jI8iYmDAR8EzY9A7Wn1NsSCmROqZbh/lmvjzPYFoMpIzncArJGl0L9vTKNaQM6 MRiorZyAUvBbvRmKtGbgcwRV5/XjpHI7Xi/pEgwuUr7VNluRrDSo9BSLVCZJvGbuWltR ITtA== 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=ihXC2HiiYMKXSpC6M6Il6sHAA7ZrY8nJsA58n/MMk7w=; b=tKUvgrZnv4P7IwTsFR4YuWDNptu5x7FvuoHKjrPiel2E7u39RxiZ+1rhQRVj+j7Yey y+g7zj70bZifDo1psHCsNh4Af5+3NKqwEnAC+gko0wKf4PFKJtwQQw/K7hqNi5mFxOXr Km+lBDUeOHxWjgMB2N62lZseDnXiS2cKJYYWvrzcGjxdL5PIDTw3tF12lODjfMVUQ5Ab tCTTjI/bxN9iqhwQNSUlma9AarHmCdUH5h4dInYq+Idb31tM3TKi44MEKmCFWI9IMSsD kNusyFlFFmIW7A3deKjcdfbgOldThYGDSQluRVnQNLUuNF4B9lamfAQee4Nh/Xxkp09Z fL0g== X-Gm-Message-State: AOAM531NwLurwYEnWiCaSwjU3jAfCdnzo20sKNVdWwyfxVUTEWFHS4TZ /aDISnDwJGv/dGMi8U+kT2Tozr/XUk34ElgS3tM= X-Google-Smtp-Source: ABdhPJxErjZybX6soSrTYGg1pcOu5YtycPfse7AYAmfc2HvtvvwrXxUQhki/vENl6RaYOLy3XisKMpVir5YUwgpINiw= X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:4cd1:da86:e91b:70b4]) (user=samitolvanen job=sendgmr) by 2002:a0c:c345:: with SMTP id j5mr10638318qvi.52.1617319959483; Thu, 01 Apr 2021 16:32:39 -0700 (PDT) Date: Thu, 1 Apr 2021 16:32:08 -0700 In-Reply-To: <20210401233216.2540591-1-samitolvanen@google.com> Message-Id: <20210401233216.2540591-11-samitolvanen@google.com> Mime-Version: 1.0 References: <20210401233216.2540591-1-samitolvanen@google.com> X-Mailer: git-send-email 2.31.0.208.g409f899ff0-goog Subject: [PATCH v5 10/18] lkdtm: use function_nocfi From: Sami Tolvanen To: Kees Cook Cc: Nathan Chancellor , Nick Desaulniers , Masahiro Yamada , Will Deacon , Jessica Yu , Arnd Bergmann , Tejun Heo , "Paul E. McKenney" , Christoph Hellwig , Peter Zijlstra , Sedat Dilek , Mark Rutland , Catalin Marinas , bpf@vger.kernel.org, linux-hardening@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kbuild@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Sami Tolvanen Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org To ensure we take the actual address of a function in kernel text, use function_nocfi. Otherwise, with CONFIG_CFI_CLANG, the compiler replaces the address with a pointer to the CFI jump table, which is actually in the module when compiled with CONFIG_LKDTM=m. Signed-off-by: Sami Tolvanen Acked-by: Kees Cook --- drivers/misc/lkdtm/usercopy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/misc/lkdtm/usercopy.c b/drivers/misc/lkdtm/usercopy.c index 109e8d4302c1..15d220ef35a5 100644 --- a/drivers/misc/lkdtm/usercopy.c +++ b/drivers/misc/lkdtm/usercopy.c @@ -314,7 +314,7 @@ void lkdtm_USERCOPY_KERNEL(void) pr_info("attempting bad copy_to_user from kernel text: %px\n", vm_mmap); - if (copy_to_user((void __user *)user_addr, vm_mmap, + if (copy_to_user((void __user *)user_addr, function_nocfi(vm_mmap), unconst + PAGE_SIZE)) { pr_warn("copy_to_user failed, but lacked Oops\n"); goto free_user;