From patchwork Fri Jul 25 08:22:24 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Yufen X-Patchwork-Id: 373609 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 9D8E21400A0 for ; Fri, 25 Jul 2014 18:24:44 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759929AbaGYIYi (ORCPT ); Fri, 25 Jul 2014 04:24:38 -0400 Received: from szxga03-in.huawei.com ([119.145.14.66]:35750 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759918AbaGYIYg (ORCPT ); Fri, 25 Jul 2014 04:24:36 -0400 Received: from 172.24.2.119 (EHLO SZXEML453-HUB.china.huawei.com) ([172.24.2.119]) by szxrg03-dlp.huawei.com (MOS 4.4.3-GA FastPath queued) with ESMTP id ASB58006; Fri, 25 Jul 2014 16:24:13 +0800 (CST) Received: from localhost (10.177.25.231) by SZXEML453-HUB.china.huawei.com (10.82.67.196) with Microsoft SMTP Server id 14.3.158.1; Fri, 25 Jul 2014 16:24:04 +0800 From: Wangyufen To: CC: , Linus Torvalds , Wang Yufen Subject: [PATCH v2 3/8] Add file_ns_capable() helper function for open-time capability checking Date: Fri, 25 Jul 2014 16:22:24 +0800 Message-ID: <1406276549-6616-4-git-send-email-wangyufen@huawei.com> X-Mailer: git-send-email 1.8.1.msysgit.1 In-Reply-To: <1406276549-6616-1-git-send-email-wangyufen@huawei.com> References: <1406276549-6616-1-git-send-email-wangyufen@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.177.25.231] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A02020A.53D2142E.000B,ss=1,re=0.000,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2011-05-27 18:58:46 X-Mirapoint-Loop-Id: 7eb419dc116245fd287eab091be7da0c Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Linus Torvalds Nothing is using it yet, but this will allow us to delay the open-time checks to use time, without breaking the normal UNIX permission semantics where permissions are determined by the opener (and the file descriptor can then be passed to a different process, or the process can drop capabilities). Signed-off-by: Linus Torvalds Signed-off-by: Wang Yufen --- include/linux/capability.h | 3 ++- kernel/capability.c | 24 ++++++++++++++++++++++++ 2 files changed, 26 insertions(+), 1 deletion(-) diff --git a/include/linux/capability.h b/include/linux/capability.h index 12d52de..7273027 100644 --- a/include/linux/capability.h +++ b/include/linux/capability.h @@ -373,7 +373,7 @@ struct cpu_vfs_cap_data { #define CAP_TO_MASK(x) (1 << ((x) & 31)) /* mask for indexed __u32 */ #ifdef __KERNEL__ - +struct file; struct dentry; struct user_namespace; @@ -548,6 +548,7 @@ extern bool has_ns_capability_noaudit(struct task_struct *t, extern bool capable(int cap); extern bool ns_capable(struct user_namespace *ns, int cap); extern bool nsown_capable(int cap); +extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap); /* audit system wants to get cap info from files as well */ extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps); diff --git a/kernel/capability.c b/kernel/capability.c index 3f1adb6..cc8c4845 100644 --- a/kernel/capability.c +++ b/kernel/capability.c @@ -393,6 +393,30 @@ bool ns_capable(struct user_namespace *ns, int cap) EXPORT_SYMBOL(ns_capable); /** + * file_ns_capable - Determine if the file's opener had a capability in effect + * @file: The file we want to check + * @ns: The usernamespace we want the capability in + * @cap: The capability to be tested for + * + * Return true if task that opened the file had a capability in effect + * when the file was opened. + * + * This does not set PF_SUPERPRIV because the caller may not + * actually be privileged. + */ +bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap) +{ + if (WARN_ON_ONCE(!cap_valid(cap))) + return false; + + if (security_capable(file->f_cred, ns, cap) == 0) + return true; + + return false; +} +EXPORT_SYMBOL(file_ns_capable); + +/** * capable - Determine if the current task has a superior capability in effect * @cap: The capability to be tested for *