1 files changed, 151 insertions, 113 deletions

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index b04f88eed09..ee9cb3795c2 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -9,93 +9,71 @@
 #include <linux/types.h>
 #include <linux/wait.h>
 
-static bool should_merge(struct fsnotify_event *old, struct fsnotify_event *new)
+#include "fanotify.h"
+
+static bool should_merge(struct fsnotify_event *old_fsn,
+			 struct fsnotify_event *new_fsn)
 {
-	pr_debug("%s: old=%p new=%p\n", __func__, old, new);
-
-	if (old->to_tell == new->to_tell &&
-	    old->data_type == new->data_type &&
-	    old->tgid == new->tgid) {
-		switch (old->data_type) {
-		case (FSNOTIFY_EVENT_PATH):
-			if ((old->path.mnt == new->path.mnt) &&
-			    (old->path.dentry == new->path.dentry))
-				return true;
-		case (FSNOTIFY_EVENT_NONE):
-			return true;
-		default:
-			BUG();
-		};
-	}
+	struct fanotify_event_info *old, *new;
+
+	pr_debug("%s: old=%p new=%p\n", __func__, old_fsn, new_fsn);
+	old = FANOTIFY_E(old_fsn);
+	new = FANOTIFY_E(new_fsn);
+
+	if (old_fsn->inode == new_fsn->inode && old->tgid == new->tgid &&
+	    old->path.mnt == new->path.mnt &&
+	    old->path.dentry == new->path.dentry)
+		return true;
 	return false;
 }
 
 /* and the list better be locked by something too! */
-static struct fsnotify_event *fanotify_merge(struct list_head *list,
-					     struct fsnotify_event *event)
+static int fanotify_merge(struct list_head *list, struct fsnotify_event *event)
 {
-	struct fsnotify_event_holder *test_holder;
-	struct fsnotify_event *test_event = NULL;
-	struct fsnotify_event *new_event;
+	struct fsnotify_event *test_event;
+	bool do_merge = false;
 
 	pr_debug("%s: list=%p event=%p\n", __func__, list, event);
 
+#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
+	/*
+	 * Don't merge a permission event with any other event so that we know
+	 * the event structure we have created in fanotify_handle_event() is the
+	 * one we should check for permission response.
+	 */
+	if (event->mask & FAN_ALL_PERM_EVENTS)
+		return 0;
+#endif
 
-	list_for_each_entry_reverse(test_holder, list, event_list) {
-		if (should_merge(test_holder->event, event)) {
-			test_event = test_holder->event;
+	list_for_each_entry_reverse(test_event, list, list) {
+		if (should_merge(test_event, event)) {
+			do_merge = true;
 			break;
 		}
 	}
 
-	if (!test_event)
-		return NULL;
-
-	fsnotify_get_event(test_event);
-
-	/* if they are exactly the same we are done */
-	if (test_event->mask == event->mask)
-		return test_event;
-
-	/*
-	 * if the refcnt == 2 this is the only queue
-	 * for this event and so we can update the mask
-	 * in place.
-	 */
-	if (atomic_read(&test_event->refcnt) == 2) {
-		test_event->mask |= event->mask;
-		return test_event;
-	}
-
-	new_event = fsnotify_clone_event(test_event);
-
-	/* done with test_event */
-	fsnotify_put_event(test_event);
+	if (!do_merge)
+		return 0;
 
-	/* couldn't allocate memory, merge was not possible */
-	if (unlikely(!new_event))
-		return ERR_PTR(-ENOMEM);
-
-	/* build new event and replace it on the list */
-	new_event->mask = (test_event->mask | event->mask);
-	fsnotify_replace_event(test_holder, new_event);
-
-	/* we hold a reference on new_event from clone_event */
-	return new_event;
+	test_event->mask |= event->mask;
+	return 1;
 }
 
 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
-static int fanotify_get_response_from_access(struct fsnotify_group *group,
-					     struct fsnotify_event *event)
+static int fanotify_get_response(struct fsnotify_group *group,
+				 struct fanotify_perm_event_info *event)
 {
 	int ret;
 
 	pr_debug("%s: group=%p event=%p\n", __func__, group, event);
 
-	wait_event(group->fanotify_data.access_waitq, event->response);
+	wait_event(group->fanotify_data.access_waitq, event->response ||
+				atomic_read(&group->fanotify_data.bypass_perm));
+
+	if (!event->response) /* bypass_perm set */
+		return 0;
 
 	/* userspace responded, convert to something usable */
-	spin_lock(&event->lock);
 	switch (event->response) {
 	case FAN_ALLOW:
 		ret = 0;
@@ -105,7 +83,6 @@ static int fanotify_get_response_from_access(struct fsnotify_group *group,
 		ret = -EPERM;
 	}
 	event->response = 0;
-	spin_unlock(&event->lock);
 
 	pr_debug("%s: group=%p event=%p about to return ret=%d\n", __func__,
 		 group, event, ret);
@@ -114,58 +91,17 @@ static int fanotify_get_response_from_access(struct fsnotify_group *group,
 }
 #endif
 
-static int fanotify_handle_event(struct fsnotify_group *group,
-				 struct fsnotify_mark *inode_mark,
-				 struct fsnotify_mark *fanotify_mark,
-				 struct fsnotify_event *event)
-{
-	int ret = 0;
-	struct fsnotify_event *notify_event = NULL;
-
-	BUILD_BUG_ON(FAN_ACCESS != FS_ACCESS);
-	BUILD_BUG_ON(FAN_MODIFY != FS_MODIFY);
-	BUILD_BUG_ON(FAN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE);
-	BUILD_BUG_ON(FAN_CLOSE_WRITE != FS_CLOSE_WRITE);
-	BUILD_BUG_ON(FAN_OPEN != FS_OPEN);
-	BUILD_BUG_ON(FAN_EVENT_ON_CHILD != FS_EVENT_ON_CHILD);
-	BUILD_BUG_ON(FAN_Q_OVERFLOW != FS_Q_OVERFLOW);
-	BUILD_BUG_ON(FAN_OPEN_PERM != FS_OPEN_PERM);
-	BUILD_BUG_ON(FAN_ACCESS_PERM != FS_ACCESS_PERM);
-	BUILD_BUG_ON(FAN_ONDIR != FS_ISDIR);
-
-	pr_debug("%s: group=%p event=%p\n", __func__, group, event);
-
-	notify_event = fsnotify_add_notify_event(group, event, NULL, fanotify_merge);
-	if (IS_ERR(notify_event))
-		return PTR_ERR(notify_event);
-
-#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
-	if (event->mask & FAN_ALL_PERM_EVENTS) {
-		/* if we merged we need to wait on the new event */
-		if (notify_event)
-			event = notify_event;
-		ret = fanotify_get_response_from_access(group, event);
-	}
-#endif
-
-	if (notify_event)
-		fsnotify_put_event(notify_event);
-
-	return ret;
-}
-
-static bool fanotify_should_send_event(struct fsnotify_group *group,
-				       struct inode *to_tell,
-				       struct fsnotify_mark *inode_mark,
+static bool fanotify_should_send_event(struct fsnotify_mark *inode_mark,
 				       struct fsnotify_mark *vfsmnt_mark,
-				       __u32 event_mask, void *data, int data_type)
+				       u32 event_mask,
+				       void *data, int data_type)
 {
 	__u32 marks_mask, marks_ignored_mask;
 	struct path *path = data;
 
-	pr_debug("%s: group=%p to_tell=%p inode_mark=%p vfsmnt_mark=%p "
-		 "mask=%x data=%p data_type=%d\n", __func__, group, to_tell,
-		 inode_mark, vfsmnt_mark, event_mask, data, data_type);
+	pr_debug("%s: inode_mark=%p vfsmnt_mark=%p mask=%x data=%p"
+		 " data_type=%d\n", __func__, inode_mark, vfsmnt_mark,
+		 event_mask, data, data_type);
 
 	/* if we don't have enough info to send an event to userspace say no */
 	if (data_type != FSNOTIFY_EVENT_PATH)
@@ -206,6 +142,93 @@ static bool fanotify_should_send_event(struct fsnotify_group *group,
 	return false;
 }
 
+struct fanotify_event_info *fanotify_alloc_event(struct inode *inode, u32 mask,
+						 struct path *path)
+{
+	struct fanotify_event_info *event;
+
+#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
+	if (mask & FAN_ALL_PERM_EVENTS) {
+		struct fanotify_perm_event_info *pevent;
+
+		pevent = kmem_cache_alloc(fanotify_perm_event_cachep,
+					  GFP_KERNEL);
+		if (!pevent)
+			return NULL;
+		event = &pevent->fae;
+		pevent->response = 0;
+		goto init;
+	}
+#endif
+	event = kmem_cache_alloc(fanotify_event_cachep, GFP_KERNEL);
+	if (!event)
+		return NULL;
+init: __maybe_unused
+	fsnotify_init_event(&event->fse, inode, mask);
+	event->tgid = get_pid(task_tgid(current));
+	if (path) {
+		event->path = *path;
+		path_get(&event->path);
+	} else {
+		event->path.mnt = NULL;
+		event->path.dentry = NULL;
+	}
+	return event;
+}
+
+static int fanotify_handle_event(struct fsnotify_group *group,
+				 struct inode *inode,
+				 struct fsnotify_mark *inode_mark,
+				 struct fsnotify_mark *fanotify_mark,
+				 u32 mask, void *data, int data_type,
+				 const unsigned char *file_name, u32 cookie)
+{
+	int ret = 0;
+	struct fanotify_event_info *event;
+	struct fsnotify_event *fsn_event;
+
+	BUILD_BUG_ON(FAN_ACCESS != FS_ACCESS);
+	BUILD_BUG_ON(FAN_MODIFY != FS_MODIFY);
+	BUILD_BUG_ON(FAN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE);
+	BUILD_BUG_ON(FAN_CLOSE_WRITE != FS_CLOSE_WRITE);
+	BUILD_BUG_ON(FAN_OPEN != FS_OPEN);
+	BUILD_BUG_ON(FAN_EVENT_ON_CHILD != FS_EVENT_ON_CHILD);
+	BUILD_BUG_ON(FAN_Q_OVERFLOW != FS_Q_OVERFLOW);
+	BUILD_BUG_ON(FAN_OPEN_PERM != FS_OPEN_PERM);
+	BUILD_BUG_ON(FAN_ACCESS_PERM != FS_ACCESS_PERM);
+	BUILD_BUG_ON(FAN_ONDIR != FS_ISDIR);
+
+	if (!fanotify_should_send_event(inode_mark, fanotify_mark, mask, data,
+					data_type))
+		return 0;
+
+	pr_debug("%s: group=%p inode=%p mask=%x\n", __func__, group, inode,
+		 mask);
+
+	event = fanotify_alloc_event(inode, mask, data);
+	if (unlikely(!event))
+		return -ENOMEM;
+
+	fsn_event = &event->fse;
+	ret = fsnotify_add_notify_event(group, fsn_event, fanotify_merge);
+	if (ret) {
+		/* Permission events shouldn't be merged */
+		BUG_ON(ret == 1 && mask & FAN_ALL_PERM_EVENTS);
+		/* Our event wasn't used in the end. Free it. */
+		fsnotify_destroy_event(group, fsn_event);
+
+		return 0;
+	}
+
+#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
+	if (mask & FAN_ALL_PERM_EVENTS) {
+		ret = fanotify_get_response(group, FANOTIFY_PE(fsn_event));
+		fsnotify_destroy_event(group, fsn_event);
+	}
+#endif
+	return ret;
+}
+
 static void fanotify_free_group_priv(struct fsnotify_group *group)
 {
 	struct user_struct *user;
@@ -215,10 +238,25 @@ static void fanotify_free_group_priv(struct fsnotify_group *group)
 	free_uid(user);
 }
 
+static void fanotify_free_event(struct fsnotify_event *fsn_event)
+{
+	struct fanotify_event_info *event;
+
+	event = FANOTIFY_E(fsn_event);
+	path_put(&event->path);
+	put_pid(event->tgid);
+#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
+	if (fsn_event->mask & FAN_ALL_PERM_EVENTS) {
+		kmem_cache_free(fanotify_perm_event_cachep,
+				FANOTIFY_PE(fsn_event));
+		return;
+	}
+#endif
+	kmem_cache_free(fanotify_event_cachep, event);
+}
+
 const struct fsnotify_ops fanotify_fsnotify_ops = {
 	.handle_event = fanotify_handle_event,
-	.should_send_event = fanotify_should_send_event,
 	.free_group_priv = fanotify_free_group_priv,
-	.free_event_priv = NULL,
-	.freeing_mark = NULL,
+	.free_event = fanotify_free_event,
 };