From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752793Ab1AYCFL (ORCPT ); Mon, 24 Jan 2011 21:05:11 -0500 Received: from smtp.outflux.net ([198.145.64.163]:45740 "EHLO smtp.outflux.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752143Ab1AYCFJ (ORCPT ); Mon, 24 Jan 2011 21:05:09 -0500 Date: Mon, 24 Jan 2011 18:04:50 -0800 From: Kees Cook To: linux-kernel@vger.kernel.org Cc: Rusty Russell , Tejun Heo , Marcus Meissner , Jason Wessel , Eugene Teo , Andrew Morton , Joe Perches , Bjorn Helgaas , Len Brown , Changli Gao , Dan Rosenberg Subject: [PATCH 1/2] use %pK for /proc/kallsyms and /proc/modules Message-ID: <20110125020450.GL4979@outflux.net> References: <20110125020321.GK4979@outflux.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20110125020321.GK4979@outflux.net> Organization: Canonical X-HELO: www.outflux.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Instead of messing with permissions on these files, use %pK for kernel addresses to reduce potential information leaks that might be used to help target kernel privilege escalation exploits. Note that this changes %x to %p, so some legitimately 0 values in /proc/kallsyms will change from 00000000 to "(null)". Additionally, when compiling with -Wformat, these harmless warnings are emitted: warning: '0' flag used with ‘%p’ gnu_printf format Signed-off-by: Kees Cook --- kernel/kallsyms.c | 4 ++-- kernel/module.c | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 6f6d091..074b762 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -477,11 +477,11 @@ static int s_show(struct seq_file *m, void *p) */ type = iter->exported ? toupper(iter->type) : tolower(iter->type); - seq_printf(m, "%0*lx %c %s\t[%s]\n", + seq_printf(m, "%0*pK %c %s\t[%s]\n", (int)(2 * sizeof(void *)), iter->value, type, iter->name, iter->module_name); } else - seq_printf(m, "%0*lx %c %s\n", + seq_printf(m, "%0*pK %c %s\n", (int)(2 * sizeof(void *)), iter->value, iter->type, iter->name); return 0; diff --git a/kernel/module.c b/kernel/module.c index 34e00b7..748465c 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1168,7 +1168,7 @@ static ssize_t module_sect_show(struct module_attribute *mattr, { struct module_sect_attr *sattr = container_of(mattr, struct module_sect_attr, mattr); - return sprintf(buf, "0x%lx\n", sattr->address); + return sprintf(buf, "0x%pK\n", sattr->address); } static void free_sect_attrs(struct module_sect_attrs *sect_attrs) @@ -3224,7 +3224,7 @@ static int m_show(struct seq_file *m, void *p) mod->state == MODULE_STATE_COMING ? "Loading": "Live"); /* Used by oprofile and other similar tools. */ - seq_printf(m, " 0x%p", mod->module_core); + seq_printf(m, " 0x%pK", mod->module_core); /* Taints info */ if (mod->taints) -- 1.7.2.3 -- Kees Cook Ubuntu Security Team