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 92E05C433E5 for ; Tue, 14 Jul 2020 19:01:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6C10222209 for ; Tue, 14 Jul 2020 19:01:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594753282; bh=c4nFP8A0K47Tn15OIczsmZVFSM5T1Rd/zIRoUYKhxn0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=XCynrHUweb/SxUhKl3BieQIWXOGSYg6f0/c+6AXKfv+vJWUHkhJxKvlsgw6BvIfSP mwFIlhi0RENsvKUhn2T6FQoXLuP2vrwn+ISTYLbkKrvOmqAoEgXEwoKkoUpTB8CoFu kLVtIKviKM43f//9rwsYNjUZBO2nkENnQxArVJQg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731041AbgGNTBP (ORCPT ); Tue, 14 Jul 2020 15:01:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:58890 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730671AbgGNTAG (ORCPT ); Tue, 14 Jul 2020 15:00:06 -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 DF416229CA; Tue, 14 Jul 2020 19:00:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594753206; bh=c4nFP8A0K47Tn15OIczsmZVFSM5T1Rd/zIRoUYKhxn0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZKp6/DGBNivU1cDMgP0rndw36AJhD/clwZ5952k1dphIFBT8k5lavmKv3eGIleIgd f/cMswKKbav9wjC7VkPx1A+/hJY87qEAQ/mIwzxdNmMRkS8/ORUqeI6Ulu235jFK2e KyjTRUw7KVkqRWTlrnSb4JN4Vv0Q4Yzo4w63scLI= 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 5.7 130/166] module: Do not expose section addresses to non-CAP_SYSLOG Date: Tue, 14 Jul 2020 20:44:55 +0200 Message-Id: <20200714184122.058394297@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200714184115.844176932@linuxfoundation.org> References: <20200714184115.844176932@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 @@ -1527,8 +1527,8 @@ 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) @@ -4351,7 +4351,7 @@ 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;