From mboxrd@z Thu Jan 1 00:00:00 1970 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=-10.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 ECF74C433E7 for ; Tue, 14 Jul 2020 18:47:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C58E822B2C for ; Tue, 14 Jul 2020 18:47:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594752462; bh=FrW5svSSOMr6F6SuCMiGrVaNwk3DE5YpZW0VtD3OlHY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=iEOwfDS+Gca6oeJXeT+oe7hOKQ1fBS38Bt43fn81CzaJeRxDxBB/MHQOewzCP036Y GLRtPhq+NB5UYoQTG56uOY9Mbdx3RdNhMQFLJ6hL6VI3WuCqtTIdcfzyEBsFTPlnWs f2jYSVBnNOUoR5MLHgcl1BavFjF985Ss7A8eycE4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729792AbgGNSrl (ORCPT ); Tue, 14 Jul 2020 14:47:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:42790 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729723AbgGNSri (ORCPT ); Tue, 14 Jul 2020 14:47:38 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3FB4D22B2C; Tue, 14 Jul 2020 18:47:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594752457; bh=FrW5svSSOMr6F6SuCMiGrVaNwk3DE5YpZW0VtD3OlHY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xaAvRnONvkZemAES5cErBf7B17PMwaZv8yv6/REzpstNAH20gDcQ/L7uBPrxcIXd+ fnj2GaBIOPKSreUWqbh4fUDIU94JDFrXgVgmSrFhu5uruc1/eFLd/e3iTlrJWxfEzu T0zHmpntsdlRu1CN+09lzW/kQJvKAbjlLK8KMGZw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dominik Czarnota , Jessica Yu , Kees Cook Subject: [PATCH 4.19 49/58] module: Do not expose section addresses to non-CAP_SYSLOG Date: Tue, 14 Jul 2020 20:44:22 +0200 Message-Id: <20200714184058.596597029@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200714184056.149119318@linuxfoundation.org> References: <20200714184056.149119318@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Kees Cook commit b25a7c5af9051850d4f3d93ca500056ab6ec724b upstream. The printing of section addresses in /sys/module/*/sections/* was not using the correct credentials to evaluate visibility. Before: # cat /sys/module/*/sections/.*text 0xffffffffc0458000 ... # capsh --drop=CAP_SYSLOG -- -c "cat /sys/module/*/sections/.*text" 0xffffffffc0458000 ... After: # cat /sys/module/*/sections/*.text 0xffffffffc0458000 ... # capsh --drop=CAP_SYSLOG -- -c "cat /sys/module/*/sections/.*text" 0x0000000000000000 ... Additionally replaces the existing (safe) /proc/modules check with file->f_cred for consistency. Reported-by: Dominik Czarnota Fixes: be71eda5383f ("module: Fix display of wrong module .text address") Cc: stable@vger.kernel.org Tested-by: Jessica Yu Acked-by: Jessica Yu Signed-off-by: Kees Cook Signed-off-by: Greg Kroah-Hartman --- kernel/module.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/kernel/module.c +++ b/kernel/module.c @@ -1471,8 +1471,8 @@ static ssize_t module_sect_read(struct f if (pos != 0) return -EINVAL; - return sprintf(buf, "0x%px\n", kptr_restrict < 2 ? - (void *)sattr->address : NULL); + return sprintf(buf, "0x%px\n", + kallsyms_show_value(file->f_cred) ? (void *)sattr->address : NULL); } static void free_sect_attrs(struct module_sect_attrs *sect_attrs) @@ -4260,7 +4260,7 @@ static int modules_open(struct inode *in if (!err) { struct seq_file *m = file->private_data; - m->private = kallsyms_show_value(current_cred()) ? NULL : (void *)8ul; + m->private = kallsyms_show_value(file->f_cred) ? NULL : (void *)8ul; } return err;