From patchwork Wed Mar 31 21:27:14 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 12176475 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, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 1E24EC001BB for ; Wed, 31 Mar 2021 21:28:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 036D761075 for ; Wed, 31 Mar 2021 21:28:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232793AbhCaV2R (ORCPT ); Wed, 31 Mar 2021 17:28:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51834 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232813AbhCaV1o (ORCPT ); Wed, 31 Mar 2021 17:27:44 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 09E27C061762 for ; Wed, 31 Mar 2021 14:27:44 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id x8so3714936ybo.6 for ; Wed, 31 Mar 2021 14:27:44 -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=LhQny/aeJmeAJ3bCETNM8gy3/qff2yzp1+GBUrzrBDs=; b=km1dlNMsZVD+nYKyhmf8suslG6lRpTXA9bXfPOZq3XJD2bh9lwyHlyugNqkc/9xIHZ pvZZvVE7uTiP4xcSdTYcIUDfgVzPvR8B7rp/SUuIegT/xhp5Kgp8M2Jfv/MMMGMErURD D9lFaSTH90mT4zzz7CkOxbEyPbFaLhhQWqZx9kshO8db8Eo6StC3w+wbFjJuHk4jG3HN ucAsImNaXJzMhnj+fyaph3WhubhiwK8ZKwoWXX0hwNzxpHCWqtnmqIC8+kn65eGYZQAL IxDudopx6hMfpUdyShz//HZdprJ0b8BJcZVh1a1jajI/rhbjlvcxdscLYnc6MfVzw/7Z xOcw== 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=LhQny/aeJmeAJ3bCETNM8gy3/qff2yzp1+GBUrzrBDs=; b=AipsIh6p3b7GLBgSo2HJkgCD5kZZ02/7CnHFD+E64RhfxaQVbI4/hBeHnzmP6c9Fxo QqTeYGNYAm7Fd8zHvQFrj+mb6rfwAaX7brseZU8XSXbeKuGQS9YiU8ef8/IZtQnaAl/0 gfnSSSXcW8zU2kAsPYNWEnM1g7Ic8kdmT2vNwouLHs0Yf3iGTCzZyd+O0jwh8t1Y3RFS o2ZHLnb7cNoaPNx27oLmGiI+hxMI01t3vGjiQm/p0cHMPn9l5k0469100LDXfpboLnKr fE84o1s0HOyb1fbrwhxbNCOBUhzmjbLm91ExrunyvoLaJOPguSLznjJ0dtjxxTcyG3VZ Mu3w== X-Gm-Message-State: AOAM530A4mEQVeIYckbuefb1bYpm/DF/E2hkHExzeDkiWZ3mUmeEHxwZ aqZ0oybAE5zynlHbP8RO2rbxazz6E0Ns736zv0o= X-Google-Smtp-Source: ABdhPJwLju6B+haVkuwTRD6OTE7Kj+Fskb9zJBbkaGFlIanyE03asSCx14sDc0Ys7LCvhLw3MkN686iAQEZQHDgH42E= X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:7933:7015:a5d5:3835]) (user=samitolvanen job=sendgmr) by 2002:a25:38c6:: with SMTP id f189mr7492638yba.183.1617226063121; Wed, 31 Mar 2021 14:27:43 -0700 (PDT) Date: Wed, 31 Mar 2021 14:27:14 -0700 In-Reply-To: <20210331212722.2746212-1-samitolvanen@google.com> Message-Id: <20210331212722.2746212-11-samitolvanen@google.com> Mime-Version: 1.0 References: <20210331212722.2746212-1-samitolvanen@google.com> X-Mailer: git-send-email 2.31.0.291.g576ba9dcdaf-goog Subject: [PATCH v4 10/17] 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 , 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;