Initial import

1 files changed, 519 insertions, 0 deletions

diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c
new file mode 100644
index 000000000..6e30024d9
--- /dev/null
+++ b/kernel/audit_watch.c
@@ -0,0 +1,519 @@
+/* audit_watch.c -- watching inodes
+ *
+ * Copyright 2003-2009 Red Hat, Inc.
+ * Copyright 2005 Hewlett-Packard Development Company, L.P.
+ * Copyright 2005 IBM Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/audit.h>
+#include <linux/kthread.h>
+#include <linux/mutex.h>
+#include <linux/fs.h>
+#include <linux/fsnotify_backend.h>
+#include <linux/namei.h>
+#include <linux/netlink.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/security.h>
+#include "audit.h"
+
+/*
+ * Reference counting:
+ *
+ * audit_parent: lifetime is from audit_init_parent() to receipt of an FS_IGNORED
+ * 	event.  Each audit_watch holds a reference to its associated parent.
+ *
+ * audit_watch: if added to lists, lifetime is from audit_init_watch() to
+ * 	audit_remove_watch().  Additionally, an audit_watch may exist
+ * 	temporarily to assist in searching existing filter data.  Each
+ * 	audit_krule holds a reference to its associated watch.
+ */
+
+struct audit_watch {
+	atomic_t		count;	/* reference count */
+	dev_t			dev;	/* associated superblock device */
+	char			*path;	/* insertion path */
+	unsigned long		ino;	/* associated inode number */
+	struct audit_parent	*parent; /* associated parent */
+	struct list_head	wlist;	/* entry in parent->watches list */
+	struct list_head	rules;	/* anchor for krule->rlist */
+};
+
+struct audit_parent {
+	struct list_head	watches; /* anchor for audit_watch->wlist */
+	struct fsnotify_mark mark; /* fsnotify mark on the inode */
+};
+
+/* fsnotify handle. */
+static struct fsnotify_group *audit_watch_group;
+
+/* fsnotify events we care about. */
+#define AUDIT_FS_WATCH (FS_MOVE | FS_CREATE | FS_DELETE | FS_DELETE_SELF |\
+			FS_MOVE_SELF | FS_EVENT_ON_CHILD)
+
+static void audit_free_parent(struct audit_parent *parent)
+{
+	WARN_ON(!list_empty(&parent->watches));
+	kfree(parent);
+}
+
+static void audit_watch_free_mark(struct fsnotify_mark *entry)
+{
+	struct audit_parent *parent;
+
+	parent = container_of(entry, struct audit_parent, mark);
+	audit_free_parent(parent);
+}
+
+static void audit_get_parent(struct audit_parent *parent)
+{
+	if (likely(parent))
+		fsnotify_get_mark(&parent->mark);
+}
+
+static void audit_put_parent(struct audit_parent *parent)
+{
+	if (likely(parent))
+		fsnotify_put_mark(&parent->mark);
+}
+
+/*
+ * Find and return the audit_parent on the given inode.  If found a reference
+ * is taken on this parent.
+ */
+static inline struct audit_parent *audit_find_parent(struct inode *inode)
+{
+	struct audit_parent *parent = NULL;
+	struct fsnotify_mark *entry;
+
+	entry = fsnotify_find_inode_mark(audit_watch_group, inode);
+	if (entry)
+		parent = container_of(entry, struct audit_parent, mark);
+
+	return parent;
+}
+
+void audit_get_watch(struct audit_watch *watch)
+{
+	atomic_inc(&watch->count);
+}
+
+void audit_put_watch(struct audit_watch *watch)
+{
+	if (atomic_dec_and_test(&watch->count)) {
+		WARN_ON(watch->parent);
+		WARN_ON(!list_empty(&watch->rules));
+		kfree(watch->path);
+		kfree(watch);
+	}
+}
+
+static void audit_remove_watch(struct audit_watch *watch)
+{
+	list_del(&watch->wlist);
+	audit_put_parent(watch->parent);
+	watch->parent = NULL;
+	audit_put_watch(watch); /* match initial get */
+}
+
+char *audit_watch_path(struct audit_watch *watch)
+{
+	return watch->path;
+}
+
+int audit_watch_compare(struct audit_watch *watch, unsigned long ino, dev_t dev)
+{
+	return (watch->ino != (unsigned long)-1) &&
+		(watch->ino == ino) &&
+		(watch->dev == dev);
+}
+
+/* Initialize a parent watch entry. */
+static struct audit_parent *audit_init_parent(struct path *path)
+{
+	struct inode *inode = d_backing_inode(path->dentry);
+	struct audit_parent *parent;
+	int ret;
+
+	parent = kzalloc(sizeof(*parent), GFP_KERNEL);
+	if (unlikely(!parent))
+		return ERR_PTR(-ENOMEM);
+
+	INIT_LIST_HEAD(&parent->watches);
+
+	fsnotify_init_mark(&parent->mark, audit_watch_free_mark);
+	parent->mark.mask = AUDIT_FS_WATCH;
+	ret = fsnotify_add_mark(&parent->mark, audit_watch_group, inode, NULL, 0);
+	if (ret < 0) {
+		audit_free_parent(parent);
+		return ERR_PTR(ret);
+	}
+
+	return parent;
+}
+
+/* Initialize a watch entry. */
+static struct audit_watch *audit_init_watch(char *path)
+{
+	struct audit_watch *watch;
+
+	watch = kzalloc(sizeof(*watch), GFP_KERNEL);
+	if (unlikely(!watch))
+		return ERR_PTR(-ENOMEM);
+
+	INIT_LIST_HEAD(&watch->rules);
+	atomic_set(&watch->count, 1);
+	watch->path = path;
+	watch->dev = (dev_t)-1;
+	watch->ino = (unsigned long)-1;
+
+	return watch;
+}
+
+/* Translate a watch string to kernel respresentation. */
+int audit_to_watch(struct audit_krule *krule, char *path, int len, u32 op)
+{
+	struct audit_watch *watch;
+
+	if (!audit_watch_group)
+		return -EOPNOTSUPP;
+
+	if (path[0] != '/' || path[len-1] == '/' ||
+	    krule->listnr != AUDIT_FILTER_EXIT ||
+	    op != Audit_equal ||
+	    krule->inode_f || krule->watch || krule->tree)
+		return -EINVAL;
+
+	watch = audit_init_watch(path);
+	if (IS_ERR(watch))
+		return PTR_ERR(watch);
+
+	audit_get_watch(watch);
+	krule->watch = watch;
+
+	return 0;
+}
+
+/* Duplicate the given audit watch.  The new watch's rules list is initialized
+ * to an empty list and wlist is undefined. */
+static struct audit_watch *audit_dupe_watch(struct audit_watch *old)
+{
+	char *path;
+	struct audit_watch *new;
+
+	path = kstrdup(old->path, GFP_KERNEL);
+	if (unlikely(!path))
+		return ERR_PTR(-ENOMEM);
+
+	new = audit_init_watch(path);
+	if (IS_ERR(new)) {
+		kfree(path);
+		goto out;
+	}
+
+	new->dev = old->dev;
+	new->ino = old->ino;
+	audit_get_parent(old->parent);
+	new->parent = old->parent;
+
+out:
+	return new;
+}
+
+static void audit_watch_log_rule_change(struct audit_krule *r, struct audit_watch *w, char *op)
+{
+	if (audit_enabled) {
+		struct audit_buffer *ab;
+		ab = audit_log_start(NULL, GFP_NOFS, AUDIT_CONFIG_CHANGE);
+		if (unlikely(!ab))
+			return;
+		audit_log_format(ab, "auid=%u ses=%u op=",
+				 from_kuid(&init_user_ns, audit_get_loginuid(current)),
+				 audit_get_sessionid(current));
+		audit_log_string(ab, op);
+		audit_log_format(ab, " path=");
+		audit_log_untrustedstring(ab, w->path);
+		audit_log_key(ab, r->filterkey);
+		audit_log_format(ab, " list=%d res=1", r->listnr);
+		audit_log_end(ab);
+	}
+}
+
+/* Update inode info in audit rules based on filesystem event. */
+static void audit_update_watch(struct audit_parent *parent,
+			       const char *dname, dev_t dev,
+			       unsigned long ino, unsigned invalidating)
+{
+	struct audit_watch *owatch, *nwatch, *nextw;
+	struct audit_krule *r, *nextr;
+	struct audit_entry *oentry, *nentry;
+
+	mutex_lock(&audit_filter_mutex);
+	/* Run all of the watches on this parent looking for the one that
+	 * matches the given dname */
+	list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
+		if (audit_compare_dname_path(dname, owatch->path,
+					     AUDIT_NAME_FULL))
+			continue;
+
+		/* If the update involves invalidating rules, do the inode-based
+		 * filtering now, so we don't omit records. */
+		if (invalidating && !audit_dummy_context())
+			audit_filter_inodes(current, current->audit_context);
+
+		/* updating ino will likely change which audit_hash_list we
+		 * are on so we need a new watch for the new list */
+		nwatch = audit_dupe_watch(owatch);
+		if (IS_ERR(nwatch)) {
+			mutex_unlock(&audit_filter_mutex);
+			audit_panic("error updating watch, skipping");
+			return;
+		}
+		nwatch->dev = dev;
+		nwatch->ino = ino;
+
+		list_for_each_entry_safe(r, nextr, &owatch->rules, rlist) {
+
+			oentry = container_of(r, struct audit_entry, rule);
+			list_del(&oentry->rule.rlist);
+			list_del_rcu(&oentry->list);
+
+			nentry = audit_dupe_rule(&oentry->rule);
+			if (IS_ERR(nentry)) {
+				list_del(&oentry->rule.list);
+				audit_panic("error updating watch, removing");
+			} else {
+				int h = audit_hash_ino((u32)ino);
+
+				/*
+				 * nentry->rule.watch == oentry->rule.watch so
+				 * we must drop that reference and set it to our
+				 * new watch.
+				 */
+				audit_put_watch(nentry->rule.watch);
+				audit_get_watch(nwatch);
+				nentry->rule.watch = nwatch;
+				list_add(&nentry->rule.rlist, &nwatch->rules);
+				list_add_rcu(&nentry->list, &audit_inode_hash[h]);
+				list_replace(&oentry->rule.list,
+					     &nentry->rule.list);
+			}
+
+			audit_watch_log_rule_change(r, owatch, "updated_rules");
+
+			call_rcu(&oentry->rcu, audit_free_rule_rcu);
+		}
+
+		audit_remove_watch(owatch);
+		goto add_watch_to_parent; /* event applies to a single watch */
+	}
+	mutex_unlock(&audit_filter_mutex);
+	return;
+
+add_watch_to_parent:
+	list_add(&nwatch->wlist, &parent->watches);
+	mutex_unlock(&audit_filter_mutex);
+	return;
+}
+
+/* Remove all watches & rules associated with a parent that is going away. */
+static void audit_remove_parent_watches(struct audit_parent *parent)
+{
+	struct audit_watch *w, *nextw;
+	struct audit_krule *r, *nextr;
+	struct audit_entry *e;
+
+	mutex_lock(&audit_filter_mutex);
+	list_for_each_entry_safe(w, nextw, &parent->watches, wlist) {
+		list_for_each_entry_safe(r, nextr, &w->rules, rlist) {
+			e = container_of(r, struct audit_entry, rule);
+			audit_watch_log_rule_change(r, w, "remove_rule");
+			list_del(&r->rlist);
+			list_del(&r->list);
+			list_del_rcu(&e->list);
+			call_rcu(&e->rcu, audit_free_rule_rcu);
+		}
+		audit_remove_watch(w);
+	}
+	mutex_unlock(&audit_filter_mutex);
+
+	fsnotify_destroy_mark(&parent->mark, audit_watch_group);
+}
+
+/* Get path information necessary for adding watches. */
+static int audit_get_nd(struct audit_watch *watch, struct path *parent)
+{
+	struct dentry *d = kern_path_locked(watch->path, parent);
+	if (IS_ERR(d))
+		return PTR_ERR(d);
+	mutex_unlock(&d_backing_inode(parent->dentry)->i_mutex);
+	if (d_is_positive(d)) {
+		/* update watch filter fields */
+		watch->dev = d_backing_inode(d)->i_sb->s_dev;
+		watch->ino = d_backing_inode(d)->i_ino;
+	}
+	dput(d);
+	return 0;
+}
+
+/* Associate the given rule with an existing parent.
+ * Caller must hold audit_filter_mutex. */
+static void audit_add_to_parent(struct audit_krule *krule,
+				struct audit_parent *parent)
+{
+	struct audit_watch *w, *watch = krule->watch;
+	int watch_found = 0;
+
+	BUG_ON(!mutex_is_locked(&audit_filter_mutex));
+
+	list_for_each_entry(w, &parent->watches, wlist) {
+		if (strcmp(watch->path, w->path))
+			continue;
+
+		watch_found = 1;
+
+		/* put krule's and initial refs to temporary watch */
+		audit_put_watch(watch);
+		audit_put_watch(watch);
+
+		audit_get_watch(w);
+		krule->watch = watch = w;
+		break;
+	}
+
+	if (!watch_found) {
+		audit_get_parent(parent);
+		watch->parent = parent;
+
+		list_add(&watch->wlist, &parent->watches);
+	}
+	list_add(&krule->rlist, &watch->rules);
+}
+
+/* Find a matching watch entry, or add this one.
+ * Caller must hold audit_filter_mutex. */
+int audit_add_watch(struct audit_krule *krule, struct list_head **list)
+{
+	struct audit_watch *watch = krule->watch;
+	struct audit_parent *parent;
+	struct path parent_path;
+	int h, ret = 0;
+
+	mutex_unlock(&audit_filter_mutex);
+
+	/* Avoid calling path_lookup under audit_filter_mutex. */
+	ret = audit_get_nd(watch, &parent_path);
+
+	/* caller expects mutex locked */
+	mutex_lock(&audit_filter_mutex);
+
+	if (ret)
+		return ret;
+
+	/* either find an old parent or attach a new one */
+	parent = audit_find_parent(d_backing_inode(parent_path.dentry));
+	if (!parent) {
+		parent = audit_init_parent(&parent_path);
+		if (IS_ERR(parent)) {
+			ret = PTR_ERR(parent);
+			goto error;
+		}
+	}
+
+	audit_add_to_parent(krule, parent);
+
+	/* match get in audit_find_parent or audit_init_parent */
+	audit_put_parent(parent);
+
+	h = audit_hash_ino((u32)watch->ino);
+	*list = &audit_inode_hash[h];
+error:
+	path_put(&parent_path);
+	return ret;
+}
+
+void audit_remove_watch_rule(struct audit_krule *krule)
+{
+	struct audit_watch *watch = krule->watch;
+	struct audit_parent *parent = watch->parent;
+
+	list_del(&krule->rlist);
+
+	if (list_empty(&watch->rules)) {
+		audit_remove_watch(watch);
+
+		if (list_empty(&parent->watches)) {
+			audit_get_parent(parent);
+			fsnotify_destroy_mark(&parent->mark, audit_watch_group);
+			audit_put_parent(parent);
+		}
+	}
+}
+
+/* Update watch data in audit rules based on fsnotify events. */
+static int audit_watch_handle_event(struct fsnotify_group *group,
+				    struct inode *to_tell,
+				    struct fsnotify_mark *inode_mark,
+				    struct fsnotify_mark *vfsmount_mark,
+				    u32 mask, void *data, int data_type,
+				    const unsigned char *dname, u32 cookie)
+{
+	struct inode *inode;
+	struct audit_parent *parent;
+
+	parent = container_of(inode_mark, struct audit_parent, mark);
+
+	BUG_ON(group != audit_watch_group);
+
+	switch (data_type) {
+	case (FSNOTIFY_EVENT_PATH):
+		inode = d_backing_inode(((struct path *)data)->dentry);
+		break;
+	case (FSNOTIFY_EVENT_INODE):
+		inode = (struct inode *)data;
+		break;
+	default:
+		BUG();
+		inode = NULL;
+		break;
+	};
+
+	if (mask & (FS_CREATE|FS_MOVED_TO) && inode)
+		audit_update_watch(parent, dname, inode->i_sb->s_dev, inode->i_ino, 0);
+	else if (mask & (FS_DELETE|FS_MOVED_FROM))
+		audit_update_watch(parent, dname, (dev_t)-1, (unsigned long)-1, 1);
+	else if (mask & (FS_DELETE_SELF|FS_UNMOUNT|FS_MOVE_SELF))
+		audit_remove_parent_watches(parent);
+
+	return 0;
+}
+
+static const struct fsnotify_ops audit_watch_fsnotify_ops = {
+	.handle_event = 	audit_watch_handle_event,
+};
+
+static int __init audit_watch_init(void)
+{
+	audit_watch_group = fsnotify_alloc_group(&audit_watch_fsnotify_ops);
+	if (IS_ERR(audit_watch_group)) {
+		audit_watch_group = NULL;
+		audit_panic("cannot create audit fsnotify group");
+	}
+	return 0;
+}
+device_initcall(audit_watch_init);