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=-6.8 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS autolearn=ham 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 E5B72C433F4 for ; Thu, 20 Sep 2018 00:19:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5FBD021524 for ; Thu, 20 Sep 2018 00:19:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=yahoo.com header.i=@yahoo.com header.b="DlKlfX4g" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5FBD021524 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=schaufler-ca.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733173AbeITGAM (ORCPT ); Thu, 20 Sep 2018 02:00:12 -0400 Received: from sonic305-10.consmr.mail.bf2.yahoo.com ([74.6.133.49]:35098 "EHLO sonic305-10.consmr.mail.bf2.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725941AbeITGAM (ORCPT ); Thu, 20 Sep 2018 02:00:12 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1537402785; bh=7PaE4c6vH6epcNtkr4DDShFdEhBrlpQzzMvglnMFATc=; h=Subject:To:References:From:Date:In-Reply-To:From:Subject; b=DlKlfX4gpvG25hIF1yA24yc6sxJcme8WWxomXKj4VZvMhgmuMKM643h+1tw+2vJyFO03QqbdpuLDhv1bT3gpzwdWglpSZfcm9rlBcwYfTGpkWmP63D2hFPD/ycvrd3V9GVvm1fuZaVokMpwG4ObaQTZWCR4l7uCFc6J1krMbsqjICaQuMHWjJ0aRfkBUSVNiS1igdIK/s78Qiwpw3FI1jjQg8ZarCRIIttbEHat7I7dmb8JEqzT+7p9yMOv6sD2PrOERNiBaGjtEh6ejhFj/j/9iB3/TcRCVcIxDE7LLvhIrArsNvy5VLtVF1CN8z1Kj6YeaUIRapAdvmuZgUsYF3Q== X-YMail-OSG: h1cqc7UVM1nKsQo4oR9dBhxdn__u_O3kkN_We4reo3.wZewEJuYuG0o4lJvGv24 OLQJJ4DoYfQXpPce2IEn0fk_w5Zr0AdlujjxkSI4E_eCcwMhcVCaIxaUF28FIx_gMhmhJJKIUnqv .tbkUUDI93TYPvrsSNxZQV3CHxxdT7TleQyL4WC9yuvIUL1p_91RdyGvYhBnQseBIESpSwAO.KH5 tDkBXukQzs58fJBrQLLkxMpK6MfpjCdH.gZ64JCO4FogIXAwAx7d9gly8n2VLqcCPXg88wZvnjQ8 cQPrngTxqTl5hlLTwrC7mSkjOOiYNSWzIdnlVAKEZ4c0Ffz7XtQ_Ty0EZqt93epzM9rLOLrG8qSx UEsXbioDfMa0bKpK8ZOWf_4HEzmjXqhZOBL8mLXSwQNlbed0AeGvbJUpLTlUs1ofbBqX.G_.efzo u.bT0mh42xGO7GaPT_WMmLk8WA8aMLvFMsyIl2ofs1qWs5aH1E3RMOGE7AnzajMqBgks6JeU1Wt3 BWXWUqgNPjF_S1MURa2WNJzdyEi0tMa2pY1R_w6bP0Ex3.GXNZwmHIqs5ezgNbarsbEKL.pS8wfs sb.Vk4qqQl0jxtIux8rWxVKmzvH9DJn2k_Au4gL.LvnW_XtVY3h.O1rnJCgiyZ2ct0GeVwHFd.U3 JVTAkjo2zMDyHpsVIGAcwDpukBQlrbtCN1J5um1yd1d8vWS4mkWoOa6M6Ju7UI50pJespo8bBXsx urOME45677AqlBlYQSq.Acwho.7_kDLdPhKXVWsp4mUYHE547ZkKJnqua1KFdsfrOA9_XgTRn9A9 j71L.4QjqfIrGDhoawMMd7Xy0DsHQjrn8W1jfdridN_1RuVii6X21XjsQyzCZcyq3fCYEC6aki9A G_1kidHu59GwBmbr6kxh0._ybTYf4G4PFgh3Y7CzgoDiTc3Y5dnLv_hYmjENHZKi5vWT_QDeqLVS Nu2kSa6oxNgPJLOXbITej0KjVG_QviCcN2ocD.WN15mkUMQPnRBqormtV5pEXIm04Zg1P9i_Ck.R APhSBwyBfMwMq_xUB Received: from sonic.gate.mail.ne1.yahoo.com by sonic305.consmr.mail.bf2.yahoo.com with HTTP; Thu, 20 Sep 2018 00:19:45 +0000 Received: from c-67-169-65-224.hsd1.ca.comcast.net (EHLO [192.168.0.102]) ([67.169.65.224]) by smtp412.mail.bf1.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID 317a6311162862b8a2b2525eefea9b84; Thu, 20 Sep 2018 00:19:42 +0000 (UTC) Subject: [PATCH v3 01/16] procfs: add smack subdir to attrs To: LSM , James Morris , SE Linux , LKLM , John Johansen , Kees Cook , Tetsuo Handa , Paul Moore , Stephen Smalley , "linux-fsdevel@vger.kernel.org" , Alexey Dobriyan , =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= , Salvatore Mesoraca References: <748c61cb-b6fa-c36d-a7b3-2315ff6292af@schaufler-ca.com> From: Casey Schaufler Message-ID: <0b83f6f7-c037-0aa9-9ba0-9d66bba8c5d2@schaufler-ca.com> Date: Wed, 19 Sep 2018 17:19:39 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <748c61cb-b6fa-c36d-a7b3-2315ff6292af@schaufler-ca.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org procfs: add smack subdir to attrs Back in 2007 I made what turned out to be a rather serious mistake in the implementation of the Smack security module. The SELinux module used an interface in /proc to manipulate the security context on processes. Rather than use a similar interface, I used the same interface. The AppArmor team did likewise. Now /proc/.../attr/current will tell you the security "context" of the process, but it will be different depending on the security module you're using. This patch provides a subdirectory in /proc/.../attr for Smack. Smack user space can use the "current" file in this subdirectory and never have to worry about getting SELinux attributes by mistake. Programs that use the old interface will continue to work (or fail, as the case may be) as before. The proposed S.A.R.A security module is dependent on the mechanism to create its own attr subdirectory. The original implementation is by Kees Cook. Signed-off-by: Casey Schaufler --- Documentation/admin-guide/LSM/index.rst | 13 +++-- fs/proc/base.c | 64 +++++++++++++++++++++---- fs/proc/internal.h | 1 + include/linux/security.h | 15 ++++-- security/security.c | 24 ++++++++-- 5 files changed, 96 insertions(+), 21 deletions(-) diff --git a/Documentation/admin-guide/LSM/index.rst b/Documentation/admin-guide/LSM/index.rst index c980dfe9abf1..9842e21afd4a 100644 --- a/Documentation/admin-guide/LSM/index.rst +++ b/Documentation/admin-guide/LSM/index.rst @@ -17,9 +17,8 @@ MAC extensions, other extensions can be built using the LSM to provide specific changes to system operation when these tweaks are not available in the core functionality of Linux itself. -Without a specific LSM built into the kernel, the default LSM will be the -Linux capabilities system. Most LSMs choose to extend the capabilities -system, building their checks on top of the defined capability hooks. +The Linux capabilities modules will always be included. This may be +followed by any number of "minor" modules and at most one "major" module. For more details on capabilities, see ``capabilities(7)`` in the Linux man-pages project. @@ -30,6 +29,14 @@ order in which checks are made. The capability module will always be first, followed by any "minor" modules (e.g. Yama) and then the one "major" module (e.g. SELinux) if there is one configured. +Process attributes associated with "major" security modules should +be accessed and maintained using the special files in ``/proc/.../attr``. +A security module may maintain a module specific subdirectory there, +named after the module. ``/proc/.../attr/smack`` is provided by the Smack +security module and contains all its special files. The files directly +in ``/proc/.../attr`` remain as legacy interfaces for modules that provide +subdirectories. + .. toctree:: :maxdepth: 1 diff --git a/fs/proc/base.c b/fs/proc/base.c index ccf86f16d9f0..bd2dd85310fe 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -140,9 +140,13 @@ struct pid_entry { #define REG(NAME, MODE, fops) \ NOD(NAME, (S_IFREG|(MODE)), NULL, &fops, {}) #define ONE(NAME, MODE, show) \ - NOD(NAME, (S_IFREG|(MODE)), \ + NOD(NAME, (S_IFREG|(MODE)), \ NULL, &proc_single_file_operations, \ { .proc_show = show } ) +#define ATTR(LSM, NAME, MODE) \ + NOD(NAME, (S_IFREG|(MODE)), \ + NULL, &proc_pid_attr_operations, \ + { .lsm = LSM }) /* * Count the number of hardlinks for the pid_entry table, excluding the . @@ -2503,7 +2507,7 @@ static ssize_t proc_pid_attr_read(struct file * file, char __user * buf, if (!task) return -ESRCH; - length = security_getprocattr(task, + length = security_getprocattr(task, PROC_I(inode)->op.lsm, (char*)file->f_path.dentry->d_name.name, &p); put_task_struct(task); @@ -2552,7 +2556,9 @@ static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf, if (rv < 0) goto out_free; - rv = security_setprocattr(file->f_path.dentry->d_name.name, page, count); + rv = security_setprocattr(PROC_I(inode)->op.lsm, + file->f_path.dentry->d_name.name, page, + count); mutex_unlock(¤t->signal->cred_guard_mutex); out_free: kfree(page); @@ -2566,13 +2572,53 @@ static const struct file_operations proc_pid_attr_operations = { .llseek = generic_file_llseek, }; +#define LSM_DIR_OPS(LSM) \ +static int proc_##LSM##_attr_dir_iterate(struct file *filp, \ + struct dir_context *ctx) \ +{ \ + return proc_pident_readdir(filp, ctx, \ + LSM##_attr_dir_stuff, \ + ARRAY_SIZE(LSM##_attr_dir_stuff)); \ +} \ +\ +static const struct file_operations proc_##LSM##_attr_dir_ops = { \ + .read = generic_read_dir, \ + .iterate = proc_##LSM##_attr_dir_iterate, \ + .llseek = default_llseek, \ +}; \ +\ +static struct dentry *proc_##LSM##_attr_dir_lookup(struct inode *dir, \ + struct dentry *dentry, unsigned int flags) \ +{ \ + return proc_pident_lookup(dir, dentry, \ + LSM##_attr_dir_stuff, \ + ARRAY_SIZE(LSM##_attr_dir_stuff)); \ +} \ +\ +static const struct inode_operations proc_##LSM##_attr_dir_inode_ops = { \ + .lookup = proc_##LSM##_attr_dir_lookup, \ + .getattr = pid_getattr, \ + .setattr = proc_setattr, \ +} + +#ifdef CONFIG_SECURITY_SMACK +static const struct pid_entry smack_attr_dir_stuff[] = { + ATTR("smack", "current", 0666), +}; +LSM_DIR_OPS(smack); +#endif + static const struct pid_entry attr_dir_stuff[] = { - REG("current", S_IRUGO|S_IWUGO, proc_pid_attr_operations), - REG("prev", S_IRUGO, proc_pid_attr_operations), - REG("exec", S_IRUGO|S_IWUGO, proc_pid_attr_operations), - REG("fscreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations), - REG("keycreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations), - REG("sockcreate", S_IRUGO|S_IWUGO, proc_pid_attr_operations), + ATTR(NULL, "current", 0666), + ATTR(NULL, "prev", 0444), + ATTR(NULL, "exec", 0666), + ATTR(NULL, "fscreate", 0666), + ATTR(NULL, "keycreate", 0666), + ATTR(NULL, "sockcreate", 0666), +#ifdef CONFIG_SECURITY_SMACK + DIR("smack", 0555, + proc_smack_attr_dir_inode_ops, proc_smack_attr_dir_ops), +#endif }; static int proc_attr_dir_readdir(struct file *file, struct dir_context *ctx) diff --git a/fs/proc/internal.h b/fs/proc/internal.h index 5185d7f6a51e..d4f9989063d0 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -81,6 +81,7 @@ union proc_op { int (*proc_show)(struct seq_file *m, struct pid_namespace *ns, struct pid *pid, struct task_struct *task); + const char *lsm; }; struct proc_inode { diff --git a/include/linux/security.h b/include/linux/security.h index 75f4156c84d7..418de5d20ffb 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -390,8 +390,10 @@ int security_sem_semctl(struct kern_ipc_perm *sma, int cmd); int security_sem_semop(struct kern_ipc_perm *sma, struct sembuf *sops, unsigned nsops, int alter); void security_d_instantiate(struct dentry *dentry, struct inode *inode); -int security_getprocattr(struct task_struct *p, char *name, char **value); -int security_setprocattr(const char *name, void *value, size_t size); +int security_getprocattr(struct task_struct *p, const char *lsm, char *name, + char **value); +int security_setprocattr(const char *lsm, const char *name, void *value, + size_t size); int security_netlink_send(struct sock *sk, struct sk_buff *skb); int security_ismaclabel(const char *name); int security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen); @@ -1139,15 +1141,18 @@ static inline int security_sem_semop(struct kern_ipc_perm *sma, return 0; } -static inline void security_d_instantiate(struct dentry *dentry, struct inode *inode) +static inline void security_d_instantiate(struct dentry *dentry, + struct inode *inode) { } -static inline int security_getprocattr(struct task_struct *p, char *name, char **value) +static inline int security_getprocattr(struct task_struct *p, const char *lsm, + char *name, char **value) { return -EINVAL; } -static inline int security_setprocattr(char *name, void *value, size_t size) +static inline int security_setprocattr(const char *lsm, char *name, + void *value, size_t size) { return -EINVAL; } diff --git a/security/security.c b/security/security.c index 736e78da1ab9..3dfe75d0d373 100644 --- a/security/security.c +++ b/security/security.c @@ -1288,14 +1288,30 @@ void security_d_instantiate(struct dentry *dentry, struct inode *inode) } EXPORT_SYMBOL(security_d_instantiate); -int security_getprocattr(struct task_struct *p, char *name, char **value) +int security_getprocattr(struct task_struct *p, const char *lsm, char *name, + char **value) { - return call_int_hook(getprocattr, -EINVAL, p, name, value); + struct security_hook_list *hp; + + hlist_for_each_entry(hp, &security_hook_heads.getprocattr, list) { + if (lsm != NULL && strcmp(lsm, hp->lsm)) + continue; + return hp->hook.getprocattr(p, name, value); + } + return -EINVAL; } -int security_setprocattr(const char *name, void *value, size_t size) +int security_setprocattr(const char *lsm, const char *name, void *value, + size_t size) { - return call_int_hook(setprocattr, -EINVAL, name, value, size); + struct security_hook_list *hp; + + hlist_for_each_entry(hp, &security_hook_heads.setprocattr, list) { + if (lsm != NULL && strcmp(lsm, hp->lsm)) + continue; + return hp->hook.setprocattr(name, value, size); + } + return -EINVAL; } int security_netlink_send(struct sock *sk, struct sk_buff *skb) -- 2.17.1