From patchwork Wed May 2 15:53:17 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tyler Hicks X-Patchwork-Id: 10376013 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5C4AC6037D for ; Wed, 2 May 2018 15:54:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4D79B28F55 for ; Wed, 2 May 2018 15:54:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4224028F5A; Wed, 2 May 2018 15:54:30 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E6D3028F55 for ; Wed, 2 May 2018 15:54:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751552AbeEBPyO (ORCPT ); Wed, 2 May 2018 11:54:14 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:54846 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751100AbeEBPyL (ORCPT ); Wed, 2 May 2018 11:54:11 -0400 Received: from 2.general.tyhicks.us.vpn ([10.172.64.53] helo=sec.l.tihix.com) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1fDu54-0007uo-2l; Wed, 02 May 2018 15:54:10 +0000 From: Tyler Hicks To: linux-kernel@vger.kernel.org Cc: Kees Cook , Andy Lutomirski , Will Drewry , Paul Moore , Eric Paris , Steve Grubb , Jonathan Corbet , linux-audit@redhat.com, linux-security-module@vger.kernel.org, linux-doc@vger.kernel.org Subject: [PATCH v2 1/4] seccomp: Separate read and write code for actions_logged sysctl Date: Wed, 2 May 2018 15:53:17 +0000 Message-Id: <1525276400-7161-2-git-send-email-tyhicks@canonical.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1525276400-7161-1-git-send-email-tyhicks@canonical.com> References: <1525276400-7161-1-git-send-email-tyhicks@canonical.com> Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP Break the read and write paths of the kernel.seccomp.actions_logged sysctl into separate functions to maintain readability. An upcoming change will need to audit writes, but not reads, of this sysctl which would introduce too many conditional code paths on whether or not the 'write' parameter evaluates to true. Signed-off-by: Tyler Hicks Reviewed-by: James Morris --- kernel/seccomp.c | 60 +++++++++++++++++++++++++++++++++++--------------------- 1 file changed, 38 insertions(+), 22 deletions(-) diff --git a/kernel/seccomp.c b/kernel/seccomp.c index dc77548..f4afe67 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -1199,48 +1199,64 @@ static bool seccomp_actions_logged_from_names(u32 *actions_logged, char *names) return true; } -static int seccomp_actions_logged_handler(struct ctl_table *ro_table, int write, - void __user *buffer, size_t *lenp, - loff_t *ppos) +static int read_actions_logged(struct ctl_table *ro_table, void __user *buffer, + size_t *lenp, loff_t *ppos) { char names[sizeof(seccomp_actions_avail)]; struct ctl_table table; + + memset(names, 0, sizeof(names)); + + if (!seccomp_names_from_actions_logged(names, sizeof(names), + seccomp_actions_logged)) + return -EINVAL; + + table = *ro_table; + table.data = names; + table.maxlen = sizeof(names); + return proc_dostring(&table, 0, buffer, lenp, ppos); +} + +static int write_actions_logged(struct ctl_table *ro_table, void __user *buffer, + size_t *lenp, loff_t *ppos) +{ + char names[sizeof(seccomp_actions_avail)]; + struct ctl_table table; + u32 actions_logged; int ret; - if (write && !capable(CAP_SYS_ADMIN)) + if (!capable(CAP_SYS_ADMIN)) return -EPERM; memset(names, 0, sizeof(names)); - if (!write) { - if (!seccomp_names_from_actions_logged(names, sizeof(names), - seccomp_actions_logged)) - return -EINVAL; - } - table = *ro_table; table.data = names; table.maxlen = sizeof(names); - ret = proc_dostring(&table, write, buffer, lenp, ppos); + ret = proc_dostring(&table, 1, buffer, lenp, ppos); if (ret) return ret; - if (write) { - u32 actions_logged; - - if (!seccomp_actions_logged_from_names(&actions_logged, - table.data)) - return -EINVAL; - - if (actions_logged & SECCOMP_LOG_ALLOW) - return -EINVAL; + if (!seccomp_actions_logged_from_names(&actions_logged, table.data)) + return -EINVAL; - seccomp_actions_logged = actions_logged; - } + if (actions_logged & SECCOMP_LOG_ALLOW) + return -EINVAL; + seccomp_actions_logged = actions_logged; return 0; } +static int seccomp_actions_logged_handler(struct ctl_table *ro_table, int write, + void __user *buffer, size_t *lenp, + loff_t *ppos) +{ + if (write) + return write_actions_logged(ro_table, buffer, lenp, ppos); + else + return read_actions_logged(ro_table, buffer, lenp, ppos); +} + static struct ctl_path seccomp_sysctl_path[] = { { .procname = "kernel", }, { .procname = "seccomp", },