From patchwork Wed Aug 12 14:09:04 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Burgener X-Patchwork-Id: 11710885 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1F261109B for ; Wed, 12 Aug 2020 14:09:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 07E3020855 for ; Wed, 12 Aug 2020 14:09:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="MMAuepgi" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726512AbgHLOJS (ORCPT ); Wed, 12 Aug 2020 10:09:18 -0400 Received: from linux.microsoft.com ([13.77.154.182]:40620 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726503AbgHLOJR (ORCPT ); Wed, 12 Aug 2020 10:09:17 -0400 Received: from localhost.localdomain (c-73-172-233-15.hsd1.md.comcast.net [73.172.233.15]) by linux.microsoft.com (Postfix) with ESMTPSA id 7081920B490A; Wed, 12 Aug 2020 07:09:16 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 7081920B490A DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1597241357; bh=xF0mhOijsh/kjeAjnO2uJStDciaP9z2VfWmKbSz/F+Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=MMAuepgiLQ5aVeyPyw9DZAqf9+IgVfaArLM0OmfbMhGeJhyykQWo536l61QxKzq0+ +KV5SdgvQn8j9DS0ahkq18m+5XG52UVlkXxTtE+d2ZtQeoTw7iVF+tfsHOT4gunWHS hLet1xje/2Mys2w/fqjCsa7dDhF0ciimxoMizrIA= From: Daniel Burgener To: selinux@vger.kernel.org Cc: stephen.smalley.work@gmail.com, omosnace@redhat.com, paul@paul-moore.com Subject: [PATCH 1/4] selinux: Create function for selinuxfs directory cleanup Date: Wed, 12 Aug 2020 10:09:04 -0400 Message-Id: <20200812140907.1102299-2-dburgener@linux.microsoft.com> X-Mailer: git-send-email 2.25.4 In-Reply-To: <20200812140907.1102299-1-dburgener@linux.microsoft.com> References: <20200812140907.1102299-1-dburgener@linux.microsoft.com> MIME-Version: 1.0 Sender: selinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org Separating the cleanup from the creation will simplify two things in future patches in this series. First, the creation can be made generic, to create directories not tied to the selinux_fs_info structure. Second, we will ultimately want to reorder creation and deletion so that the deletions aren't performed until the new directory structures have already been moved into place. Signed-off-by: Daniel Burgener --- security/selinux/selinuxfs.c | 41 ++++++++++++++++++++++++------------ 1 file changed, 27 insertions(+), 14 deletions(-) diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index 131816878e50..fc914facb48f 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -355,6 +355,9 @@ static int sel_make_classes(struct selinux_fs_info *fsi, static struct dentry *sel_make_dir(struct dentry *dir, const char *name, unsigned long *ino); +/* declaration for sel_remove_old_policy_nodes */ +static void sel_remove_entries(struct dentry *de); + static ssize_t sel_read_mls(struct file *filp, char __user *buf, size_t count, loff_t *ppos) { @@ -509,11 +512,35 @@ static const struct file_operations sel_policy_ops = { .llseek = generic_file_llseek, }; +static void sel_remove_old_policy_nodes(struct selinux_fs_info *fsi) +{ + u32 i; + + /* bool_dir cleanup */ + for (i = 0; i < fsi->bool_num; i++) + kfree(fsi->bool_pending_names[i]); + kfree(fsi->bool_pending_names); + kfree(fsi->bool_pending_values); + fsi->bool_num = 0; + fsi->bool_pending_names = NULL; + fsi->bool_pending_values = NULL; + + sel_remove_entries(fsi->bool_dir); + + /* class_dir cleanup */ + sel_remove_entries(fsi->class_dir); + + /* policycap_dir cleanup */ + sel_remove_entries(fsi->policycap_dir); +} + static int sel_make_policy_nodes(struct selinux_fs_info *fsi, struct selinux_policy *newpolicy) { int ret; + sel_remove_old_policy_nodes(fsi); + ret = sel_make_bools(fsi, newpolicy); if (ret) { pr_err("SELinux: failed to load policy booleans\n"); @@ -1348,17 +1375,6 @@ static int sel_make_bools(struct selinux_fs_info *fsi, int *values = NULL; u32 sid; - /* remove any existing files */ - for (i = 0; i < fsi->bool_num; i++) - kfree(fsi->bool_pending_names[i]); - kfree(fsi->bool_pending_names); - kfree(fsi->bool_pending_values); - fsi->bool_num = 0; - fsi->bool_pending_names = NULL; - fsi->bool_pending_values = NULL; - - sel_remove_entries(dir); - ret = -ENOMEM; page = (char *)get_zeroed_page(GFP_KERNEL); if (!page) @@ -1873,9 +1889,6 @@ static int sel_make_classes(struct selinux_fs_info *fsi, int rc, nclasses, i; char **classes; - /* delete any existing entries */ - sel_remove_entries(fsi->class_dir); - rc = security_get_classes(newpolicy, &classes, &nclasses); if (rc) return rc; From patchwork Wed Aug 12 14:09:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Burgener X-Patchwork-Id: 11710889 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CD8051744 for ; Wed, 12 Aug 2020 14:09:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B49BB20855 for ; Wed, 12 Aug 2020 14:09:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="L1970Acx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726468AbgHLOJU (ORCPT ); Wed, 12 Aug 2020 10:09:20 -0400 Received: from linux.microsoft.com ([13.77.154.182]:40626 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726505AbgHLOJS (ORCPT ); Wed, 12 Aug 2020 10:09:18 -0400 Received: from localhost.localdomain (c-73-172-233-15.hsd1.md.comcast.net [73.172.233.15]) by linux.microsoft.com (Postfix) with ESMTPSA id 4609920B490D; Wed, 12 Aug 2020 07:09:17 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 4609920B490D DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1597241357; bh=h0J5zXRS82FdnJWHfZ2GyfbHIqLimH6f5CETRRANugM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=L1970AcxSai8k/HidDNRrTM66zqo3SAG9mYfwFYnKkhVb0jyy6msOSfYeJ/7cUHWv uTVJBdCg9A/yRLqaetOcqqRsIB0idwbO0Ar/RNn+ek/xasH4D65s/Qj1Um12tF/4U3 uRFstlTN9K4qy6C7Fwbf7F+ELMXWzeZh5mfjjyPI= From: Daniel Burgener To: selinux@vger.kernel.org Cc: stephen.smalley.work@gmail.com, omosnace@redhat.com, paul@paul-moore.com Subject: [PATCH 2/4] selinux: Refactor selinuxfs directory populating functions Date: Wed, 12 Aug 2020 10:09:05 -0400 Message-Id: <20200812140907.1102299-3-dburgener@linux.microsoft.com> X-Mailer: git-send-email 2.25.4 In-Reply-To: <20200812140907.1102299-1-dburgener@linux.microsoft.com> References: <20200812140907.1102299-1-dburgener@linux.microsoft.com> MIME-Version: 1.0 Sender: selinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org Make sel_make_bools and sel_make_classes take the specific elements of selinux_fs_info that they need rather than the entire struct. This will allow a future patch to pass temporary elements that are not in the selinux_fs_info struct to these functions so that the original elements can be preserved until we are ready to perform the switch over. Signed-off-by: Daniel Burgener --- security/selinux/selinuxfs.c | 45 ++++++++++++++++++++---------------- 1 file changed, 25 insertions(+), 20 deletions(-) diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index fc914facb48f..9657c3acfc8f 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -346,10 +346,12 @@ static const struct file_operations sel_policyvers_ops = { }; /* declaration for sel_write_load */ -static int sel_make_bools(struct selinux_fs_info *fsi, - struct selinux_policy *newpolicy); -static int sel_make_classes(struct selinux_fs_info *fsi, - struct selinux_policy *newpolicy); +static int sel_make_bools(struct selinux_policy *newpolicy, struct dentry *bool_dir, + unsigned int *bool_num, char ***bool_pending_names, + unsigned int **bool_pending_values); +static int sel_make_classes(struct selinux_policy *newpolicy, + struct dentry *class_dir, + unsigned long *last_class_ino); /* declaration for sel_make_class_dirs */ static struct dentry *sel_make_dir(struct dentry *dir, const char *name, @@ -541,13 +543,15 @@ static int sel_make_policy_nodes(struct selinux_fs_info *fsi, sel_remove_old_policy_nodes(fsi); - ret = sel_make_bools(fsi, newpolicy); + ret = sel_make_bools(newpolicy, fsi->bool_dir, &fsi->bool_num, + &fsi->bool_pending_names, &fsi->bool_pending_values); if (ret) { pr_err("SELinux: failed to load policy booleans\n"); return ret; } - ret = sel_make_classes(fsi, newpolicy); + ret = sel_make_classes(newpolicy, fsi->class_dir, + &fsi->last_class_ino); if (ret) { pr_err("SELinux: failed to load policy classes\n"); return ret; @@ -1361,13 +1365,13 @@ static void sel_remove_entries(struct dentry *de) #define BOOL_DIR_NAME "booleans" -static int sel_make_bools(struct selinux_fs_info *fsi, - struct selinux_policy *newpolicy) +static int sel_make_bools(struct selinux_policy *newpolicy, struct dentry *bool_dir, + unsigned int *bool_num, char ***bool_pending_names, + unsigned int **bool_pending_values) { int ret; ssize_t len; struct dentry *dentry = NULL; - struct dentry *dir = fsi->bool_dir; struct inode *inode = NULL; struct inode_security_struct *isec; char **names = NULL, *page; @@ -1386,12 +1390,12 @@ static int sel_make_bools(struct selinux_fs_info *fsi, for (i = 0; i < num; i++) { ret = -ENOMEM; - dentry = d_alloc_name(dir, names[i]); + dentry = d_alloc_name(bool_dir, names[i]); if (!dentry) goto out; ret = -ENOMEM; - inode = sel_make_inode(dir->d_sb, S_IFREG | S_IRUGO | S_IWUSR); + inode = sel_make_inode(bool_dir->d_sb, S_IFREG | S_IRUGO | S_IWUSR); if (!inode) { dput(dentry); goto out; @@ -1420,9 +1424,9 @@ static int sel_make_bools(struct selinux_fs_info *fsi, inode->i_ino = i|SEL_BOOL_INO_OFFSET; d_add(dentry, inode); } - fsi->bool_num = num; - fsi->bool_pending_names = names; - fsi->bool_pending_values = values; + *bool_num = num; + *bool_pending_names = names; + *bool_pending_values = values; free_page((unsigned long)page); return 0; @@ -1435,7 +1439,7 @@ static int sel_make_bools(struct selinux_fs_info *fsi, kfree(names); } kfree(values); - sel_remove_entries(dir); + sel_remove_entries(bool_dir); return ret; } @@ -1882,8 +1886,9 @@ static int sel_make_class_dir_entries(struct selinux_policy *newpolicy, return rc; } -static int sel_make_classes(struct selinux_fs_info *fsi, - struct selinux_policy *newpolicy) +static int sel_make_classes(struct selinux_policy *newpolicy, + struct dentry *class_dir, + unsigned long *last_class_ino) { int rc, nclasses, i; @@ -1894,13 +1899,13 @@ static int sel_make_classes(struct selinux_fs_info *fsi, return rc; /* +2 since classes are 1-indexed */ - fsi->last_class_ino = sel_class_to_ino(nclasses + 2); + *last_class_ino = sel_class_to_ino(nclasses + 2); for (i = 0; i < nclasses; i++) { struct dentry *class_name_dir; - class_name_dir = sel_make_dir(fsi->class_dir, classes[i], - &fsi->last_class_ino); + class_name_dir = sel_make_dir(class_dir, classes[i], + last_class_ino); if (IS_ERR(class_name_dir)) { rc = PTR_ERR(class_name_dir); goto out; From patchwork Wed Aug 12 14:09:06 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Burgener X-Patchwork-Id: 11710887 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7F768109B for ; Wed, 12 Aug 2020 14:09:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5B95320855 for ; Wed, 12 Aug 2020 14:09:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="W55IbATh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726518AbgHLOJU (ORCPT ); Wed, 12 Aug 2020 10:09:20 -0400 Received: from linux.microsoft.com ([13.77.154.182]:40640 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726468AbgHLOJS (ORCPT ); Wed, 12 Aug 2020 10:09:18 -0400 Received: from localhost.localdomain (c-73-172-233-15.hsd1.md.comcast.net [73.172.233.15]) by linux.microsoft.com (Postfix) with ESMTPSA id 17BA620B490F; Wed, 12 Aug 2020 07:09:18 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 17BA620B490F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1597241358; bh=TWaa5J7FL27uITC423BFjVEEdl8/5m1i6QAGc4Mk748=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=W55IbAThdG+xFOiMjtUl3qwZAOzw6oS2KDlxDutC9KcnehwUSTsrbpUJFK/9yPtpr J2kPuu1d3UTRgIxgNrv8zw2uiUKbUCh/+iz2xiB/ObbxQdt9+WrajRRXsJEtqQDE2d 2bhT9KVNVaec+fYg6Nqd1YyYxFMpSw8+Vv7fCCSs= From: Daniel Burgener To: selinux@vger.kernel.org Cc: stephen.smalley.work@gmail.com, omosnace@redhat.com, paul@paul-moore.com Subject: [PATCH 3/4] selinux: Standardize string literal usage for selinuxfs directory names Date: Wed, 12 Aug 2020 10:09:06 -0400 Message-Id: <20200812140907.1102299-4-dburgener@linux.microsoft.com> X-Mailer: git-send-email 2.25.4 In-Reply-To: <20200812140907.1102299-1-dburgener@linux.microsoft.com> References: <20200812140907.1102299-1-dburgener@linux.microsoft.com> MIME-Version: 1.0 Sender: selinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org Switch class and policy_capabilities directory names to be referred to with global constants, consistent with booleans directory name. This will allow for easy consistency of naming in future development. Signed-off-by: Daniel Burgener --- security/selinux/selinuxfs.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index 9657c3acfc8f..f09afdb90ddd 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -117,6 +117,10 @@ static void selinux_fs_info_free(struct super_block *sb) #define SEL_POLICYCAP_INO_OFFSET 0x08000000 #define SEL_INO_MASK 0x00ffffff +#define BOOL_DIR_NAME "booleans" +#define CLASS_DIR_NAME "class" +#define POLICYCAP_DIR_NAME "policy_capabilities" + #define TMPBUFLEN 12 static ssize_t sel_read_enforce(struct file *filp, char __user *buf, size_t count, loff_t *ppos) @@ -1363,8 +1367,6 @@ static void sel_remove_entries(struct dentry *de) shrink_dcache_parent(de); } -#define BOOL_DIR_NAME "booleans" - static int sel_make_bools(struct selinux_policy *newpolicy, struct dentry *bool_dir, unsigned int *bool_num, char ***bool_pending_names, unsigned int **bool_pending_values) @@ -2080,14 +2082,14 @@ static int sel_fill_super(struct super_block *sb, struct fs_context *fc) if (ret) goto err; - fsi->class_dir = sel_make_dir(sb->s_root, "class", &fsi->last_ino); + fsi->class_dir = sel_make_dir(sb->s_root, CLASS_DIR_NAME, &fsi->last_ino); if (IS_ERR(fsi->class_dir)) { ret = PTR_ERR(fsi->class_dir); fsi->class_dir = NULL; goto err; } - fsi->policycap_dir = sel_make_dir(sb->s_root, "policy_capabilities", + fsi->policycap_dir = sel_make_dir(sb->s_root, POLICYCAP_DIR_NAME, &fsi->last_ino); if (IS_ERR(fsi->policycap_dir)) { ret = PTR_ERR(fsi->policycap_dir); From patchwork Wed Aug 12 14:09:07 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Burgener X-Patchwork-Id: 11710891 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 14D2B109B for ; Wed, 12 Aug 2020 14:09:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC8D220855 for ; Wed, 12 Aug 2020 14:09:22 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="fu1AcrCx" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726505AbgHLOJV (ORCPT ); Wed, 12 Aug 2020 10:09:21 -0400 Received: from linux.microsoft.com ([13.77.154.182]:40656 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726503AbgHLOJV (ORCPT ); Wed, 12 Aug 2020 10:09:21 -0400 Received: from localhost.localdomain (c-73-172-233-15.hsd1.md.comcast.net [73.172.233.15]) by linux.microsoft.com (Postfix) with ESMTPSA id C444B20B4908; Wed, 12 Aug 2020 07:09:18 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com C444B20B4908 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1597241359; bh=XHpyFvAoVsbv24v7ZKPCCxLispqhFgvVSSoh+HTaOQI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fu1AcrCxI57souj+Ds6KWSzPoJ6MGSIb/zJSpQJAU1w7o+OPsHgjeuzbOTb85OVB7 3GHLCfwsKcd3Jgp7t7eqowrFd7Ut3pI3iyp3egWxUny5muzyq3iJ5d+VfE4cWKbjKV 7pYDbHgy+9MHHVVz7xEv6BbV35auc685gRjSH8N8= From: Daniel Burgener To: selinux@vger.kernel.org Cc: stephen.smalley.work@gmail.com, omosnace@redhat.com, paul@paul-moore.com Subject: [PATCH 4/4] selinux: Create new booleans, class and policycap dirs out of tree Date: Wed, 12 Aug 2020 10:09:07 -0400 Message-Id: <20200812140907.1102299-5-dburgener@linux.microsoft.com> X-Mailer: git-send-email 2.25.4 In-Reply-To: <20200812140907.1102299-1-dburgener@linux.microsoft.com> References: <20200812140907.1102299-1-dburgener@linux.microsoft.com> MIME-Version: 1.0 Sender: selinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org In order to avoid concurrency issues around selinuxfs resource availability during policy load, we first create new directories out of tree for reloaded resources, then swap them in, and finally delete the old versions. This fix focuses on concurrency in each of the three subtrees swapped, and not concurrency across the three trees. This means that it is still possible that subsequent reads to eg the booleans directory and the class directory during a policy load could see the old state for one and the new for the other. The problem of ensuring that policy loads are fully atomic from the perspective of userspace is larger than what is dealt with here. This commit focuses on ensuring that the directories contents always match either the new or the old policy state from the perspective of userspace. In the previous implementation, on policy load /sys/fs/selinux is updated by deleting the previous contents of /sys/fs/selinux/{class,booleans,policy_capabilities} and then recreating them. This means that there is a period of time when the contents of these directories do not exist which can cause race conditions as userspace relies on them for information about the policy. In addition, it means that error recovery in the event of failure is challenging. In order to demonstrate the race condition that this series fixes, you can use the following commands: while true; do cat /sys/fs/selinux/class/service/perms/status >/dev/null; done & while true; do load_policy; done; In the existing code, this will display errors fairly often as the class lookup fails. (In normal operation from systemd, this would result in a permission check which would be allowed or denied based on policy settings around unknown object classes.) After applying this patch series you should expect to no longer see such error messages. Signed-off-by: Daniel Burgener --- security/selinux/selinuxfs.c | 146 +++++++++++++++++++++++++++++------ 1 file changed, 121 insertions(+), 25 deletions(-) diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index f09afdb90ddd..e89e132aeb71 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -361,7 +362,11 @@ static int sel_make_classes(struct selinux_policy *newpolicy, static struct dentry *sel_make_dir(struct dentry *dir, const char *name, unsigned long *ino); -/* declaration for sel_remove_old_policy_nodes */ +/* declaration for sel_make_policy_nodes */ +static struct dentry *sel_make_disconnected_dir(struct super_block *sb, + unsigned long *ino); + +/* declaration for sel_make_policy_nodes */ static void sel_remove_entries(struct dentry *de); static ssize_t sel_read_mls(struct file *filp, char __user *buf, @@ -518,50 +523,109 @@ static const struct file_operations sel_policy_ops = { .llseek = generic_file_llseek, }; -static void sel_remove_old_policy_nodes(struct selinux_fs_info *fsi) +static void sel_remove_old_bool_data(unsigned int bool_num, char **bool_names, + unsigned int *bool_values) { u32 i; /* bool_dir cleanup */ - for (i = 0; i < fsi->bool_num; i++) - kfree(fsi->bool_pending_names[i]); - kfree(fsi->bool_pending_names); - kfree(fsi->bool_pending_values); - fsi->bool_num = 0; - fsi->bool_pending_names = NULL; - fsi->bool_pending_values = NULL; - - sel_remove_entries(fsi->bool_dir); - - /* class_dir cleanup */ - sel_remove_entries(fsi->class_dir); - - /* policycap_dir cleanup */ - sel_remove_entries(fsi->policycap_dir); + for (i = 0; i < bool_num; i++) + kfree(bool_names[i]); + kfree(bool_names); + kfree(bool_values); } static int sel_make_policy_nodes(struct selinux_fs_info *fsi, struct selinux_policy *newpolicy) { - int ret; + int ret = 0; + struct dentry *tmp_parent, *tmp_bool_dir, *tmp_class_dir, *tmp_policycap_dir, *old_dentry; + unsigned int tmp_bool_num, old_bool_num; + char **tmp_bool_names, **old_bool_names; + unsigned int *tmp_bool_values, *old_bool_values; + + tmp_parent = sel_make_disconnected_dir(fsi->sb, &fsi->last_ino); + if (IS_ERR(tmp_parent)) { + return PTR_ERR(tmp_parent); + } - sel_remove_old_policy_nodes(fsi); + tmp_bool_dir = sel_make_dir(tmp_parent, BOOL_DIR_NAME, &fsi->last_ino); + if (IS_ERR(tmp_bool_dir)) { + ret = PTR_ERR(tmp_bool_dir); + goto out; + } - ret = sel_make_bools(newpolicy, fsi->bool_dir, &fsi->bool_num, - &fsi->bool_pending_names, &fsi->bool_pending_values); + tmp_class_dir = sel_make_dir(tmp_parent, CLASS_DIR_NAME, &fsi->last_ino); + if (IS_ERR(tmp_class_dir)) { + ret = PTR_ERR(tmp_class_dir); + goto out; + } + + tmp_policycap_dir = sel_make_dir(tmp_parent, POLICYCAP_DIR_NAME, &fsi->last_ino); + if (IS_ERR(tmp_policycap_dir)) { + ret = PTR_ERR(tmp_policycap_dir); + goto out; + } + + ret = sel_make_bools(newpolicy, tmp_bool_dir, &tmp_bool_num, + &tmp_bool_names, &tmp_bool_values); if (ret) { pr_err("SELinux: failed to load policy booleans\n"); - return ret; + goto out; } - ret = sel_make_classes(newpolicy, fsi->class_dir, + ret = sel_make_classes(newpolicy, tmp_class_dir, &fsi->last_class_ino); if (ret) { pr_err("SELinux: failed to load policy classes\n"); - return ret; + goto out; } - return 0; + // booleans + old_dentry = fsi->bool_dir; + lock_rename(tmp_bool_dir, old_dentry); + ret = vfs_rename(tmp_parent->d_inode, tmp_bool_dir, fsi->sb->s_root->d_inode, + fsi->bool_dir, NULL, RENAME_EXCHANGE); + if (ret) { + pr_err("Failed to update boolean directory\n"); + unlock_rename(tmp_bool_dir, old_dentry); + goto out; + } + + old_bool_num = fsi->bool_num; + old_bool_names = fsi->bool_pending_names; + old_bool_values = fsi->bool_pending_values; + + fsi->bool_num = tmp_bool_num; + fsi->bool_pending_names = tmp_bool_names; + fsi->bool_pending_values = tmp_bool_values; + + sel_remove_old_bool_data(old_bool_num, old_bool_names, old_bool_values); + + fsi->bool_dir = tmp_bool_dir; + unlock_rename(tmp_bool_dir, old_dentry); + + // classes + old_dentry = fsi->class_dir; + lock_rename(tmp_class_dir, old_dentry); + ret = vfs_rename(tmp_parent->d_inode, tmp_class_dir, fsi->sb->s_root->d_inode, + fsi->class_dir, NULL, RENAME_EXCHANGE); + if (ret) { + pr_err("Failed to update class directory\n"); + unlock_rename(tmp_class_dir, old_dentry); + goto out; + } + fsi->class_dir = tmp_class_dir; + unlock_rename(tmp_class_dir, old_dentry); + +out: + // Since the other temporary dirs are children of tmp_parent + // this will handle all the cleanup in the case of a failure before + // the swapover + sel_remove_entries(tmp_parent); + dput(tmp_parent); // d_genocide() only handles the children + + return ret; } static ssize_t sel_write_load(struct file *file, const char __user *buf, @@ -1984,6 +2048,38 @@ static struct dentry *sel_make_dir(struct dentry *dir, const char *name, return dentry; } +// vfs_rename() requires a rename operation to be defined. +int sel_rename(struct inode *old_dir, struct dentry *old_dentry, + struct inode *new_dir, struct dentry *new_dentry, + unsigned int flags) +{ + if (!(flags & RENAME_EXCHANGE)) + return -EINVAL; + + return 0; +} + +const struct inode_operations sel_dir_inode_operations = { + .lookup = simple_lookup, + .rename = sel_rename, +}; + +static struct dentry *sel_make_disconnected_dir(struct super_block *sb, + unsigned long *ino) +{ + struct inode *inode = sel_make_inode(sb, S_IFDIR | S_IRUGO | S_IXUGO); + + if (!inode) + return ERR_PTR(-ENOMEM); + + inode->i_op = &sel_dir_inode_operations; + inode->i_fop = &simple_dir_operations; + inode->i_ino = ++(*ino); + /* directory inodes start off with i_nlink == 2 (for "." entry) */ + inc_nlink(inode); + return d_obtain_alias(inode); +} + #define NULL_FILE_NAME "null" static int sel_fill_super(struct super_block *sb, struct fs_context *fc)