From patchwork Sun Jul 19 15:50:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oscar Carter X-Patchwork-Id: 11672497 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A1DE713B4 for ; Sun, 19 Jul 2020 15:52:06 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 09561207EA for ; Sun, 19 Jul 2020 15:52:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=gmx.net header.i=@gmx.net header.b="SuTsQ1Ru" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 09561207EA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=gmx.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-19394-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 9801 invoked by uid 550); 19 Jul 2020 15:52:04 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 9776 invoked from network); 19 Jul 2020 15:52:03 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1595173881; bh=UxIl6mQen7XHyeByrGPPzVo5oIulQzy1cfNBw4mJwKk=; h=X-UI-Sender-Class:From:To:Cc:Subject:Date:In-Reply-To:References; b=SuTsQ1RuKd1Yyt7mauDt3BNF40vASogagV5nvvha5YSYs1cLI1Cf0lsUXEg5yW1GI Xp36OFwLS7PIaAV7aGhcOAP7yPCCzVAmt9WBdJ7wzNeZ4OiXgPspLWJpQuEfcPWkcx tEGDeKbS56bIAIBtXzlRiHz0xOLcv9DX0ipXICYw= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c From: Oscar Carter To: Steven Rostedt , Ingo Molnar , Kees Cook Cc: Oscar Carter , linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, Jann Horn Subject: [PATCH v2 1/2] kernel/trace: Prepare to remove function callback casts Date: Sun, 19 Jul 2020 17:50:32 +0200 Message-Id: <20200719155033.24201-2-oscar.carter@gmx.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200719155033.24201-1-oscar.carter@gmx.com> References: <20200719155033.24201-1-oscar.carter@gmx.com> MIME-Version: 1.0 X-Provags-ID: V03:K1:2z12NmO4u8UaSayx3JZjEGOcyrHYJ4xFELYM88klsQhmJlBUw5R ZNiIhd83afniCVMUF1UDUfbNAVXAxTD+6MtwUWxSSMssNq3DZtnzZpfuOLzGZPWH5LOHvyj 92nr89bVIbT9WYJk3uvwdohIL10+ECLUNMQ98SG3NdC87Gp1UGtAs7O3geVLHSPkJhi8Yb3 4DAG/29QWv/o6Z2sngFNA== X-Spam-Flag: NO X-UI-Out-Filterresults: notjunk:1;V03:K0:uMgpbrCNjLY=:QEGMcSDeJXgrI0HoHw1xAh LCEzKfBq8KCcJvdSmqkwUJENEdUY1slU+Il1VaseHlMpmP/rBKAyPVQt7kUCl21f42Zec7eRr ylFn9uMnJ/KL+/Ldgtlqe9cXofKoqVKMWiWSrAXUlX2SUT5he0U5+c0h78TWGZOJ06uSrOFjO GjIB/VSM0rk5KpFbljpiinl7v8f+fuQ9N6z1D9XMkrqjP2hjK6npdF91oy6K5xBo8COM9olBd ah8/SpIDNNKoxyHf+kpTAmYcoYGu77eJLvX71WPFqvcV+qNplnepzmYpnYPmeR1lag0qiOK8n 9Kw9LX1WGB3bXkak6VdLKbXoQgUTMlol1Nw99R8rDLm7ZzM5pgzXGFU72984ILTmKYb58NJfx mON0Y9t+L61bsglxxbYBSMRF96PtdTXqqdSE6f9LENIbY7UkqmwEDSP9PeYz3Aeu2Ldhr1xN1 jxIsxyNeqpNksV5v9KrsPmWtWDlhNdHD1lkFU9lzwmJvDRMx/ENaEp53Ak+tnTv4zBYmQY4js X3pkhNYjdaQQW3hMhOssrRy3Vm9GV/JblJx9elyrumAR/qZkAGskOHU5PvemkFYTon8C/5ahz QcyE1AQU0JmU+HQ+wSZoQxWf6L0M4mDVpAI4n5aeCZwHcze3oJb3lroQ9WIJ8OmNtxpiwFGWM 9t/Xf0DPdILb7ceMaZqSKkn2PzXyjozAAoafLGkDNM8Hlky9gu3zFXrIiYyVZY09zU0wbqJCK FlnG1gaMhEtThyCB4pfku/f/GotOFwL/ggbOq4UceAVqHI8fGdc9BE1q8owG2gVPowaE0SwNu BzAsjA/04wc5RU2ERuIBeBfC1Km3CcOqvebyDrFAumFs3JqNaVXC9VFB6L08/H5lKVqKBO2lF 86R/aHFMBmqg4H9nAzpRg6krVuFE5vaSj7FzlRbKhefQZ3NSMOJVpv9NcylANRC1D/u6dRhzA b5b4vMvAXFeHuZoNlaz+5gWmG+noxr8L+XAZS44yQaf1kvrzHx2bJYkmKSu4OJhXlTybMV3/i 9vIPPsaJg3ZpClrk7urOvbn6DZ7m1iHmSOydFZwn62R+wTEWYkCpsJpU2IVffOc0BCtYSIeEv 7/RRAbOwRt3ETEaRTlUoAxbUdDeNSmKQnvJCU4jfDPPuRIvybQ6J5lsDLNM3oeKCjX8m3Y62o 50hVn9noWAl+GrZIEfcn3grUXWMU/x1950r7pmiF/BmXzjBfibb57+Ubo7f9caFA1IawrI0OK AUyMIH+ecdfhkQRNdIKOCy++7Op3OBGrDDpLxbA== In an effort to enable -Wcast-function-type in the top-level Makefile to support Control Flow Integrity builds, there are the need to remove all the function callback casts. ftrace_ops_list_func() can no longer be defined as ftrace_ops_no_ops(). The reason for ftrace_ops_no_ops() is to use that when an architecture calls ftrace_ops_list_func() with only two parameters (called from assembly). And to make sure there's no C side-effects, those archs call ftrace_ops_no_ops() which only has two parameters, as the function ftrace_ops_list_func() has four parameters. This patch prepares all the infrastructure to remove the casts. Define a new function pointer to use when the archs don't support ftrace ops. Also define a union to combine this new function pointer (two parameters) with the ftrace_func_t function pointer (four parameters). This way, using this union it's possible to use two different function prototypes with the same variable. Also create two static inline helpers to set and compare against the fields of the new union type. These helpers are duplicated for the archs that support ftrace ops and for the archs that don't support ftrace ops as both cases use different function prototypes. Signed-off-by: Oscar Carter --- kernel/trace/ftrace.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) -- 2.20.1 diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 1903b80db6eb..fd8fbb422860 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -119,13 +119,45 @@ struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end; ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub; struct ftrace_ops global_ops; +typedef void (*ftrace_func_no_ops_t)(unsigned long ip, + unsigned long parent_ip); + +union ftrace_func { + ftrace_func_t ops; + ftrace_func_no_ops_t no_ops; +}; + #if ARCH_SUPPORTS_FTRACE_OPS static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op, struct pt_regs *regs); + +static inline void ftrace_set_ufunc(union ftrace_func *ufunc, + ftrace_func_t func) +{ + ufunc->ops = func; +} + +static inline bool ftrace_same_address_ufunc(union ftrace_func *ufunc, + ftrace_func_t func) +{ + return (ufunc->ops == func); +} #else /* See comment below, where ftrace_ops_list_func is defined */ static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip); #define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops) + +static inline void ftrace_set_ufunc(union ftrace_func *ufunc, + ftrace_func_no_ops_t func) +{ + ufunc->no_ops = func; +} + +static inline bool ftrace_same_address_ufunc(union ftrace_func *ufunc, + ftrace_func_no_ops_t func) +{ + return (ufunc->no_ops == func); +} #endif static inline void ftrace_ops_init(struct ftrace_ops *ops)