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-rw-r--r--fs/notify/fanotify/fanotify.c35
-rw-r--r--fs/notify/fanotify/fanotify.h3
-rw-r--r--fs/notify/fanotify/fanotify_user.c9
3 files changed, 42 insertions, 5 deletions
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 812c975df7ec..ff7b8a1cdfe1 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -77,6 +77,13 @@ static int fanotify_merge(struct list_head *list, struct fsnotify_event *event)
return 0;
}
+/*
+ * Wait for response to permission event. The function also takes care of
+ * freeing the permission event (or offloads that in case the wait is canceled
+ * by a signal). The function returns 0 in case access got allowed by userspace,
+ * -EPERM in case userspace disallowed the access, and -ERESTARTSYS in case
+ * the wait got interrupted by a signal.
+ */
static int fanotify_get_response(struct fsnotify_group *group,
struct fanotify_perm_event *event,
struct fsnotify_iter_info *iter_info)
@@ -85,8 +92,29 @@ static int fanotify_get_response(struct fsnotify_group *group,
pr_debug("%s: group=%p event=%p\n", __func__, group, event);
- wait_event(group->fanotify_data.access_waitq,
- event->state == FAN_EVENT_ANSWERED);
+ ret = wait_event_interruptible(group->fanotify_data.access_waitq,
+ event->state == FAN_EVENT_ANSWERED);
+ /* Signal pending? */
+ if (ret < 0) {
+ spin_lock(&group->notification_lock);
+ /* Event reported to userspace and no answer yet? */
+ if (event->state == FAN_EVENT_REPORTED) {
+ /* Event will get freed once userspace answers to it */
+ event->state = FAN_EVENT_CANCELED;
+ spin_unlock(&group->notification_lock);
+ return ret;
+ }
+ /* Event not yet reported? Just remove it. */
+ if (event->state == FAN_EVENT_INIT)
+ fsnotify_remove_queued_event(group, &event->fae.fse);
+ /*
+ * Event may be also answered in case signal delivery raced
+ * with wakeup. In that case we have nothing to do besides
+ * freeing the event and reporting error.
+ */
+ spin_unlock(&group->notification_lock);
+ goto out;
+ }
/* userspace responded, convert to something usable */
switch (event->response & ~FAN_AUDIT) {
@@ -104,6 +132,8 @@ static int fanotify_get_response(struct fsnotify_group *group,
pr_debug("%s: group=%p event=%p about to return ret=%d\n", __func__,
group, event, ret);
+out:
+ fsnotify_destroy_event(group, &event->fae.fse);
return ret;
}
@@ -406,7 +436,6 @@ static int fanotify_handle_event(struct fsnotify_group *group,
} else if (fanotify_is_perm_event(mask)) {
ret = fanotify_get_response(group, FANOTIFY_PE(fsn_event),
iter_info);
- fsnotify_destroy_event(group, fsn_event);
}
finish:
if (fanotify_is_perm_event(mask))
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index 480f281996d4..68b30504284c 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -12,7 +12,8 @@ extern struct kmem_cache *fanotify_perm_event_cachep;
enum {
FAN_EVENT_INIT,
FAN_EVENT_REPORTED,
- FAN_EVENT_ANSWERED
+ FAN_EVENT_ANSWERED,
+ FAN_EVENT_CANCELED,
};
/*
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 3c272f61d341..56992b32c6bb 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -147,10 +147,17 @@ static void finish_permission_event(struct fsnotify_group *group,
unsigned int response)
__releases(&group->notification_lock)
{
+ bool destroy = false;
+
assert_spin_locked(&group->notification_lock);
event->response = response;
- event->state = FAN_EVENT_ANSWERED;
+ if (event->state == FAN_EVENT_CANCELED)
+ destroy = true;
+ else
+ event->state = FAN_EVENT_ANSWERED;
spin_unlock(&group->notification_lock);
+ if (destroy)
+ fsnotify_destroy_event(group, &event->fae.fse);
}
static int process_access_response(struct fsnotify_group *group,
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