From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 2A8617D08A for ; Mon, 8 Oct 2018 11:06:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727719AbeJHSQT (ORCPT ); Mon, 8 Oct 2018 14:16:19 -0400 Received: from xavier.telenet-ops.be ([195.130.132.52]:52846 "EHLO xavier.telenet-ops.be" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727427AbeJHSQT (ORCPT ); Mon, 8 Oct 2018 14:16:19 -0400 Received: from ramsan.of.borg ([84.194.111.163]) by xavier.telenet-ops.be with bizsmtp id kz561y0033XaVaC01z56XX; Mon, 08 Oct 2018 13:05:06 +0200 Received: from rox.of.borg ([192.168.97.57]) by ramsan.of.borg with esmtp (Exim 4.86_2) (envelope-from ) id 1g9TLV-000513-UO; Mon, 08 Oct 2018 13:05:05 +0200 Received: from geert by rox.of.borg with local (Exim 4.90_1) (envelope-from ) id 1g9TLV-0006dN-TP; Mon, 08 Oct 2018 13:05:05 +0200 From: Geert Uytterhoeven To: Petr Mladek , Andy Shevchenko , "Tobin C . Harding" , Andrew Morton , Jonathan Corbet Cc: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH 2/3] lib/vsprintf: Hash legacy clock addresses Date: Mon, 8 Oct 2018 13:05:03 +0200 Message-Id: <20181008110504.25449-3-geert+renesas@glider.be> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20181008110504.25449-1-geert+renesas@glider.be> References: <20181008110504.25449-1-geert+renesas@glider.be> Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On platforms using the Common Clock Framework, "%pC" prints the clock's name. On legacy platforms, it prints the unhashed clock's address, potentially leaking sensitive information regarding the kernel layout in memory. Avoid this leak by printing the hashed address instead. To distinguish between clocks, a 32-bit unique identifier is as good as an actual pointer value. Fixes: ad67b74d2469d9b8 ("printk: hash addresses printed with %p") Signed-off-by: Geert Uytterhoeven --- Documentation/core-api/printk-formats.rst | 5 ++--- lib/vsprintf.c | 2 +- 2 files changed, 3 insertions(+), 4 deletions(-) diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst index 25dc591cb1108790..d39798c2558500d5 100644 --- a/Documentation/core-api/printk-formats.rst +++ b/Documentation/core-api/printk-formats.rst @@ -420,9 +420,8 @@ struct clk %pC pll1 %pCn pll1 -For printing struct clk structures. %pC and %pCn print the name -(Common Clock Framework) or address (legacy clock framework) of the -structure. +For printing struct clk structures. %pC and %pCn print the name of the clock +(Common Clock Framework) or a unique 32-bit ID (legacy clock framework). Passed by reference. diff --git a/lib/vsprintf.c b/lib/vsprintf.c index b5bf90731c5a5277..1fb36260a44289e8 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -1477,7 +1477,7 @@ char *clock(char *buf, char *end, struct clk *clk, struct printf_spec spec, #ifdef CONFIG_COMMON_CLK return string(buf, end, __clk_get_name(clk), spec); #else - return special_hex_number(buf, end, (unsigned long)clk, sizeof(unsigned long)); + return ptr_to_id(buf, end, clk, spec); #endif } } -- 2.17.1