fanotify: limit number of listeners per user

[pandora-kernel.git] / fs / notify / fanotify / fanotify_user.c

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index f921610..a7d9369 100644 (file)
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -18,6 +18,7 @@
 
 #define FANOTIFY_DEFAULT_MAX_EVENTS    16384
 #define FANOTIFY_DEFAULT_MAX_MARKS     8192
+#define FANOTIFY_DEFAULT_MAX_LISTENERS 128
 
 extern const struct fsnotify_ops fanotify_fsnotify_ops;
 
@@ -656,6 +657,7 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
 {
        struct fsnotify_group *group;
        int f_flags, fd;
+       struct user_struct *user;
 
        pr_debug("%s: flags=%d event_f_flags=%d\n",
                __func__, flags, event_f_flags);
@@ -666,6 +668,12 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
        if (flags & ~FAN_ALL_INIT_FLAGS)
                return -EINVAL;
 
+       user = get_current_user();
+       if (atomic_read(&user->fanotify_listeners) > FANOTIFY_DEFAULT_MAX_LISTENERS) {
+               free_uid(user);
+               return -EMFILE;
+       }
+
        f_flags = O_RDWR | FMODE_NONOTIFY;
        if (flags & FAN_CLOEXEC)
                f_flags |= O_CLOEXEC;
@@ -677,6 +685,9 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
        if (IS_ERR(group))
                return PTR_ERR(group);
 
+       group->fanotify_data.user = user;
+       atomic_inc(&user->fanotify_listeners);
+
        group->fanotify_data.f_flags = event_f_flags;
 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
        mutex_init(&group->fanotify_data.access_mutex);