audit: seperate audit inode watches into a subfile

In preparation for converting audit to use fsnotify instead of inotify we
seperate the inode watching code into it's own file.  This is similar to
how the audit tree watching code is already seperated into audit_tree.c

Signed-off-by: Eric Paris <eparis@redhat.com>

1 files changed, 14 insertions, 467 deletions

diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index e7466dd145c..9d4c93437de 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -27,7 +27,6 @@
 #include <linux/namei.h>
 #include <linux/netlink.h>
 #include <linux/sched.h>
-#include <linux/inotify.h>
 #include <linux/security.h>
 #include "audit.h"
 
@@ -44,36 +43,6 @@
  * 		be written directly provided audit_filter_mutex is held.
  */
 
-/*
- * Reference counting:
- *
- * audit_parent: lifetime is from audit_init_parent() to receipt of an IN_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_parent {
-	struct list_head	ilist;	/* entry in inotify registration list */
-	struct list_head	watches; /* associated watches */
-	struct inotify_watch	wdata;	/* inotify watch data */
-	unsigned		flags;	/* status flags */
-};
-
-/*
- * audit_parent status flags:
- *
- * AUDIT_PARENT_INVALID - set anytime rules/watches are auto-removed due to
- * a filesystem event to ensure we're adding audit watches to a valid parent.
- * Technically not needed for IN_DELETE_SELF or IN_UNMOUNT events, as we cannot
- * receive them while we have nameidata, but must be used for IN_MOVE_SELF which
- * we can receive while holding nameidata.
- */
-#define AUDIT_PARENT_INVALID	0x001
-
 /* Audit filter lists, defined in <linux/audit.h> */
 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
 	LIST_HEAD_INIT(audit_filter_list[0]),
@@ -97,41 +66,6 @@ static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
 
 DEFINE_MUTEX(audit_filter_mutex);
 
-/* Inotify events we care about. */
-#define AUDIT_IN_WATCH IN_MOVE|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF
-
-void audit_free_parent(struct inotify_watch *i_watch)
-{
-	struct audit_parent *parent;
-
-	parent = container_of(i_watch, struct audit_parent, wdata);
-	WARN_ON(!list_empty(&parent->watches));
-	kfree(parent);
-}
-
-static inline void audit_get_watch(struct audit_watch *watch)
-{
-	atomic_inc(&watch->count);
-}
-
-static 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);
-	put_inotify_watch(&watch->parent->wdata);
-	watch->parent = NULL;
-	audit_put_watch(watch); /* match initial get */
-}
-
 static inline void audit_free_rule(struct audit_entry *e)
 {
 	int i;
@@ -156,50 +90,6 @@ void audit_free_rule_rcu(struct rcu_head *head)
 	audit_free_rule(e);
 }
 
-/* Initialize a parent watch entry. */
-static struct audit_parent *audit_init_parent(struct nameidata *ndp)
-{
-	struct audit_parent *parent;
-	s32 wd;
-
-	parent = kzalloc(sizeof(*parent), GFP_KERNEL);
-	if (unlikely(!parent))
-		return ERR_PTR(-ENOMEM);
-
-	INIT_LIST_HEAD(&parent->watches);
-	parent->flags = 0;
-
-	inotify_init_watch(&parent->wdata);
-	/* grab a ref so inotify watch hangs around until we take audit_filter_mutex */
-	get_inotify_watch(&parent->wdata);
-	wd = inotify_add_watch(audit_ih, &parent->wdata,
-			       ndp->path.dentry->d_inode, AUDIT_IN_WATCH);
-	if (wd < 0) {
-		audit_free_parent(&parent->wdata);
-		return ERR_PTR(wd);
-	}
-
-	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;
-}
-
 /* Initialize an audit filterlist entry. */
 static inline struct audit_entry *audit_init_entry(u32 field_count)
 {
@@ -260,31 +150,6 @@ static inline int audit_to_inode(struct audit_krule *krule,
 	return 0;
 }
 
-/* Translate a watch string to kernel respresentation. */
-static int audit_to_watch(struct audit_krule *krule, char *path, int len,
-			  u32 op)
-{
-	struct audit_watch *watch;
-
-	if (!audit_ih)
-		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;
-}
-
 static __u32 *classes[AUDIT_SYSCALL_CLASSES];
 
 int __init audit_register_class(int class, unsigned *list)
@@ -766,7 +631,8 @@ static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
 			break;
 		case AUDIT_WATCH:
 			data->buflen += data->values[i] =
-				audit_pack_string(&bufp, krule->watch->path);
+				audit_pack_string(&bufp,
+						  audit_watch_path(krule->watch));
 			break;
 		case AUDIT_DIR:
 			data->buflen += data->values[i] =
@@ -818,7 +684,8 @@ static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
 				return 1;
 			break;
 		case AUDIT_WATCH:
-			if (strcmp(a->watch->path, b->watch->path))
+			if (strcmp(audit_watch_path(a->watch),
+				   audit_watch_path(b->watch)))
 				return 1;
 			break;
 		case AUDIT_DIR:
@@ -844,32 +711,6 @@ static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b)
 	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;
-	get_inotify_watch(&old->parent->wdata);
-	new->parent = old->parent;
-
-out:
-	return new;
-}
-
 /* Duplicate LSM field information.  The lsm_rule is opaque, so must be
  * re-initialized. */
 static inline int audit_dupe_lsm_field(struct audit_field *df,
@@ -904,8 +745,8 @@ static inline int audit_dupe_lsm_field(struct audit_field *df,
  * rule with the new rule in the filterlist, then free the old rule.
  * The rlist element is undefined; list manipulations are handled apart from
  * the initial copy. */
-static struct audit_entry *audit_dupe_rule(struct audit_krule *old,
-					   struct audit_watch *watch)
+struct audit_entry *audit_dupe_rule(struct audit_krule *old,
+				    struct audit_watch *watch)
 {
 	u32 fcount = old->field_count;
 	struct audit_entry *entry;
@@ -977,127 +818,6 @@ static struct audit_entry *audit_dupe_rule(struct audit_krule *old,
 	return entry;
 }
 
-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);
-		audit_log_format(ab, "auid=%u ses=%u op=",
-				 audit_get_loginuid(current),
-				 audit_get_sessionid(current));
-		audit_log_string(ab, op);
-		audit_log_format(ab, " path=");
-		audit_log_untrustedstring(ab, w->path);
-		if (r->filterkey) {
-			audit_log_format(ab, " key=");
-			audit_log_untrustedstring(ab, r->filterkey);
-		} else
-			audit_log_format(ab, " key=(null)");
-		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);
-	list_for_each_entry_safe(owatch, nextw, &parent->watches, wlist) {
-		if (audit_compare_dname_path(dname, owatch->path, NULL))
-			continue;
-
-		/* If the update involves invalidating rules, do the inode-based
-		 * filtering now, so we don't omit records. */
-		if (invalidating && current->audit_context)
-			audit_filter_inodes(current, current->audit_context);
-
-		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, nwatch);
-			if (IS_ERR(nentry)) {
-				list_del(&oentry->rule.list);
-				audit_panic("error updating watch, removing");
-			} else {
-				int h = audit_hash_ino((u32)ino);
-				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);
-	parent->flags |= AUDIT_PARENT_INVALID;
-	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);
-}
-
-/* Unregister inotify watches for parents on in_list.
- * Generates an IN_IGNORED event. */
-static void audit_inotify_unregister(struct list_head *in_list)
-{
-	struct audit_parent *p, *n;
-
-	list_for_each_entry_safe(p, n, in_list, ilist) {
-		list_del(&p->ilist);
-		inotify_rm_watch(audit_ih, &p->wdata);
-		/* the unpin matching the pin in audit_do_del_rule() */
-		unpin_inotify_watch(&p->wdata);
-	}
-}
-
 /* Find an existing audit rule.
  * Caller must hold audit_filter_mutex to prevent stale rule data. */
 static struct audit_entry *audit_find_rule(struct audit_entry *entry,
@@ -1135,134 +855,6 @@ out:
 	return found;
 }
 
-/* Get path information necessary for adding watches. */
-static int audit_get_nd(char *path, struct nameidata **ndp,
-			struct nameidata **ndw)
-{
-	struct nameidata *ndparent, *ndwatch;
-	int err;
-
-	ndparent = kmalloc(sizeof(*ndparent), GFP_KERNEL);
-	if (unlikely(!ndparent))
-		return -ENOMEM;
-
-	ndwatch = kmalloc(sizeof(*ndwatch), GFP_KERNEL);
-	if (unlikely(!ndwatch)) {
-		kfree(ndparent);
-		return -ENOMEM;
-	}
-
-	err = path_lookup(path, LOOKUP_PARENT, ndparent);
-	if (err) {
-		kfree(ndparent);
-		kfree(ndwatch);
-		return err;
-	}
-
-	err = path_lookup(path, 0, ndwatch);
-	if (err) {
-		kfree(ndwatch);
-		ndwatch = NULL;
-	}
-
-	*ndp = ndparent;
-	*ndw = ndwatch;
-
-	return 0;
-}
-
-/* Release resources used for watch path information. */
-static void audit_put_nd(struct nameidata *ndp, struct nameidata *ndw)
-{
-	if (ndp) {
-		path_put(&ndp->path);
-		kfree(ndp);
-	}
-	if (ndw) {
-		path_put(&ndw->path);
-		kfree(ndw);
-	}
-}
-
-/* Associate the given rule with an existing parent inotify_watch.
- * 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;
-
-	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) {
-		get_inotify_watch(&parent->wdata);
-		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. */
-static int audit_add_watch(struct audit_krule *krule, struct nameidata *ndp,
-			   struct nameidata *ndw)
-{
-	struct audit_watch *watch = krule->watch;
-	struct inotify_watch *i_watch;
-	struct audit_parent *parent;
-	int ret = 0;
-
-	/* update watch filter fields */
-	if (ndw) {
-		watch->dev = ndw->path.dentry->d_inode->i_sb->s_dev;
-		watch->ino = ndw->path.dentry->d_inode->i_ino;
-	}
-
-	/* The audit_filter_mutex must not be held during inotify calls because
-	 * we hold it during inotify event callback processing.  If an existing
-	 * inotify watch is found, inotify_find_watch() grabs a reference before
-	 * returning.
-	 */
-	mutex_unlock(&audit_filter_mutex);
-
-	if (inotify_find_watch(audit_ih, ndp->path.dentry->d_inode,
-			       &i_watch) < 0) {
-		parent = audit_init_parent(ndp);
-		if (IS_ERR(parent)) {
-			/* caller expects mutex locked */
-			mutex_lock(&audit_filter_mutex);
-			return PTR_ERR(parent);
-		}
-	} else
-		parent = container_of(i_watch, struct audit_parent, wdata);
-
-	mutex_lock(&audit_filter_mutex);
-
-	/* parent was moved before we took audit_filter_mutex */
-	if (parent->flags & AUDIT_PARENT_INVALID)
-		ret = -ENOENT;
-	else
-		audit_add_to_parent(krule, parent);
-
-	/* match get in audit_init_parent or inotify_find_watch */
-	put_inotify_watch(&parent->wdata);
-	return ret;
-}
-
 static u64 prio_low = ~0ULL/2;
 static u64 prio_high = ~0ULL/2 - 1;
 
@@ -1297,7 +889,7 @@ static inline int audit_add_rule(struct audit_entry *entry)
 
 	/* Avoid calling path_lookup under audit_filter_mutex. */
 	if (watch) {
-		err = audit_get_nd(watch->path, &ndp, &ndw);
+		err = audit_get_nd(audit_watch_path(watch), &ndp, &ndw);
 		if (err)
 			goto error;
 	}
@@ -1312,7 +904,7 @@ static inline int audit_add_rule(struct audit_entry *entry)
 		}
 		/* entry->rule.watch may have changed during audit_add_watch() */
 		watch = entry->rule.watch;
-		h = audit_hash_ino((u32)watch->ino);
+		h = audit_hash_ino((u32)audit_watch_inode(watch));
 		list = &audit_inode_hash[h];
 	}
 	if (tree) {
@@ -1364,7 +956,7 @@ error:
 static inline int audit_del_rule(struct audit_entry *entry)
 {
 	struct audit_entry  *e;
-	struct audit_watch *watch, *tmp_watch = entry->rule.watch;
+	struct audit_watch *watch = entry->rule.watch;
 	struct audit_tree *tree = entry->rule.tree;
 	struct list_head *list;
 	LIST_HEAD(inotify_list);
@@ -1386,29 +978,8 @@ static inline int audit_del_rule(struct audit_entry *entry)
 		goto out;
 	}
 
-	watch = e->rule.watch;
-	if (watch) {
-		struct audit_parent *parent = watch->parent;
-
-		list_del(&e->rule.rlist);
-
-		if (list_empty(&watch->rules)) {
-			audit_remove_watch(watch);
-
-			if (list_empty(&parent->watches)) {
-				/* Put parent on the inotify un-registration
-				 * list.  Grab a reference before releasing
-				 * audit_filter_mutex, to be released in
-				 * audit_inotify_unregister().
-				 * If filesystem is going away, just leave
-				 * the sucker alone, eviction will take
-				 * care of it.
-				 */
-				if (pin_inotify_watch(&parent->wdata))
-					list_add(&parent->ilist, &inotify_list);
-			}
-		}
-	}
+	if (e->rule.watch)
+		audit_remove_watch_rule(&e->rule, &inotify_list);
 
 	if (e->rule.tree)
 		audit_remove_tree_rule(&e->rule);
@@ -1430,8 +1001,8 @@ static inline int audit_del_rule(struct audit_entry *entry)
 		audit_inotify_unregister(&inotify_list);
 
 out:
-	if (tmp_watch)
-		audit_put_watch(tmp_watch); /* match initial get */
+	if (watch)
+		audit_put_watch(watch); /* match initial get */
 	if (tree)
 		audit_put_tree(tree);	/* that's the temporary one */
 
@@ -1785,7 +1356,7 @@ static int update_lsm_rule(struct audit_krule *r)
 		list_del(&r->list);
 	} else {
 		if (watch) {
-			list_add(&nentry->rule.rlist, &watch->rules);
+			list_add(&nentry->rule.rlist, audit_watch_rules(watch));
 			list_del(&r->rlist);
 		} else if (tree)
 			list_replace_init(&r->rlist, &nentry->rule.rlist);
@@ -1821,27 +1392,3 @@ int audit_update_lsm_rules(void)
 
 	return err;
 }
-
-/* Update watch data in audit rules based on inotify events. */
-void audit_handle_ievent(struct inotify_watch *i_watch, u32 wd, u32 mask,
-			 u32 cookie, const char *dname, struct inode *inode)
-{
-	struct audit_parent *parent;
-
-	parent = container_of(i_watch, struct audit_parent, wdata);
-
-	if (mask & (IN_CREATE|IN_MOVED_TO) && inode)
-		audit_update_watch(parent, dname, inode->i_sb->s_dev,
-				   inode->i_ino, 0);
-	else if (mask & (IN_DELETE|IN_MOVED_FROM))
-		audit_update_watch(parent, dname, (dev_t)-1, (unsigned long)-1, 1);
-	/* inotify automatically removes the watch and sends IN_IGNORED */
-	else if (mask & (IN_DELETE_SELF|IN_UNMOUNT))
-		audit_remove_parent_watches(parent);
-	/* inotify does not remove the watch, so remove it manually */
-	else if(mask & IN_MOVE_SELF) {
-		audit_remove_parent_watches(parent);
-		inotify_remove_watch_locked(audit_ih, i_watch);
-	} else if (mask & IN_IGNORED)
-		put_inotify_watch(i_watch);
-}