From patchwork Fri Mar 12 00:49:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sami Tolvanen X-Patchwork-Id: 12133463 X-Patchwork-Delegate: bpf@iogearbox.net 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 24872C28E89 for ; Fri, 12 Mar 2021 00:50:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 080E964FB9 for ; Fri, 12 Mar 2021 00:50:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231390AbhCLAtt (ORCPT ); Thu, 11 Mar 2021 19:49:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52026 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231325AbhCLAta (ORCPT ); Thu, 11 Mar 2021 19:49:30 -0500 Received: from mail-qv1-xf4a.google.com (mail-qv1-xf4a.google.com [IPv6:2607:f8b0:4864:20::f4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 92BF3C061761 for ; Thu, 11 Mar 2021 16:49:30 -0800 (PST) Received: by mail-qv1-xf4a.google.com with SMTP id dz17so16439592qvb.14 for ; Thu, 11 Mar 2021 16:49:30 -0800 (PST) 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=2z/Ob1KBSYIAdbfAk0R8ty/tB7fYk5G7Uqr3Tkugs0A=; b=HXPIDqa3ilGnJfXXoaPlqtVCFft699aj6X1ZgyB1edbMPQPGqWRvnSWZM4YgmX9SfS 3ai3WwuU9qOd0PYVJS9vjneegm7E54NnFeGwEOCUHbNdHvUn2KYwFAWWD7Pxy3fIn3E/ Xfc3wWCi1FV1pTsSPX5eZF1qhXdNrnpKo0UFrfSlSrezhbnHE7WrcLiWsJy6Z1imXMmE pl1XcbcWcj4yrpQwP/dZH8xKo9yLMRnz8bwEcH3ft5LkLXj253WTgB0wfiVs3cKNmE17 K0+LGQopZnN8pk84JQhOYLnPPcleS7MhWgmP9inB9s0BQW9FAKFgH6iAODcOkHJeB8Ze fIxA== 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=2z/Ob1KBSYIAdbfAk0R8ty/tB7fYk5G7Uqr3Tkugs0A=; b=JDXNl69hM2eoDM5t4Qkk3he7AROzr3/USPVx6e+ykN0Vk3lsEQ7NGq8DLsQXKBwMq9 SFo63Qn33g22lIq+7lONGV881yyqfZCyZJJsQ50VMTTbEsveFwzkTV4FyVnieAnhSGle oN1cNNpeMNQURWEBtyyD6CwVof4V6dl+IWLbR4Y3PhAQOP2iwZ86ZHjYGksqYK5Vt0tr G/E3kc8p4Jd/g53Z/XDWDMcKPLFYVfAods4w6QhwdJS1/GUh0ymIffYbn6ovpmCRO5r0 qc0KXzYroGw1CXH7BC+YNlpJcX1Tu/bCPfUzYPrK0tzGa7bQb8QVdMO4Hq1w6IrFBSeR V7sQ== X-Gm-Message-State: AOAM530ZN/crLnL82HPwUTVCfM2sQmK+G/U4dya49IVPuR8HLyKM8NGj LH/sfQS3/sfV7HwqCToDy+yhWngoOLLjypwD3qg= X-Google-Smtp-Source: ABdhPJxHDKETbYeoueGPafrW3BI4Uh5lPSvgOdjIw/MXWNb4TTLYLuJccKyo+tYRBmtObEJFt+syMJh09rwfHBLme60= X-Received: from samitolvanen1.mtv.corp.google.com ([2620:15c:201:2:c86b:8269:af92:55a]) (user=samitolvanen job=sendgmr) by 2002:ad4:5887:: with SMTP id dz7mr10214152qvb.12.1615510169805; Thu, 11 Mar 2021 16:49:29 -0800 (PST) Date: Thu, 11 Mar 2021 16:49:07 -0800 In-Reply-To: <20210312004919.669614-1-samitolvanen@google.com> Message-Id: <20210312004919.669614-6-samitolvanen@google.com> Mime-Version: 1.0 References: <20210312004919.669614-1-samitolvanen@google.com> X-Mailer: git-send-email 2.31.0.rc2.261.g7f71774620-goog Subject: [PATCH 05/17] workqueue: cfi: disable callback pointer check with modules From: Sami Tolvanen To: Kees Cook Cc: Nathan Chancellor , Nick Desaulniers , Masahiro Yamada , Will Deacon , Jessica Yu , Arnd Bergmann , Tejun Heo , 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, Sami Tolvanen Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org With CONFIG_CFI_CLANG, a callback function passed to __queue_delayed_work from a module points to a jump table entry defined in the module instead of the one used in the core kernel, which breaks function address equality in this check: WARN_ON_ONCE(timer->function != delayed_work_timer_fn); Disable the warning when CFI and modules are enabled. Signed-off-by: Sami Tolvanen Reviewed-by: Kees Cook --- kernel/workqueue.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 0d150da252e8..4db267e5ad2d 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1630,7 +1630,14 @@ static void __queue_delayed_work(int cpu, struct workqueue_struct *wq, struct work_struct *work = &dwork->work; WARN_ON_ONCE(!wq); - WARN_ON_ONCE(timer->function != delayed_work_timer_fn); + /* + * With CFI, timer->function can point to a jump table entry in a module, + * which fails the comparison. Disable the warning if CFI and modules are + * both enabled. + */ + if (!IS_ENABLED(CONFIG_CFI_CLANG) || !IS_ENABLED(CONFIG_MODULES)) + WARN_ON_ONCE(timer->function != delayed_work_timer_fn); + WARN_ON_ONCE(timer_pending(timer)); WARN_ON_ONCE(!list_empty(&work->entry));