Merge branch 'for-linus' of git://git.infradead.org/users/eparis/notify

* 'for-linus' of git://git.infradead.org/users/eparis/notify:
  fanotify: fill in the metadata_len field on struct fanotify_event_metadata
  fanotify: split version into version and metadata_len
  fanotify: Dont try to open a file descriptor for the overflow event
  fanotify: Introduce FAN_NOFD
  fanotify: do not leak user reference on allocation failure
  inotify: stop kernel memory leak on file creation failure
  fanotify: on group destroy allow all waiters to bypass permission check
  fanotify: Dont allow a mask of 0 if setting or removing a mark
  fanotify: correct broken ref counting in case adding a mark failed
  fanotify: if set by user unset FMODE_NONOTIFY before fsnotify_perm() is called
  fanotify: remove packed from access response message
  fanotify: deny permissions when no event was sent

7 files changed, 68 insertions, 38 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 5362af9b7372..4ff7ca530533 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1748,6 +1748,9 @@ struct file *do_filp_open(int dfd, const char *pathname,
         if (!(open_flag & O_CREAT))
                 mode = 0;
 
+        /* Must never be set by userspace */
+        open_flag &= ~FMODE_NONOTIFY;
+
         /*
          * O_SYNC is implemented as __O_SYNC|O_DSYNC.  As many places only
          * check for O_DSYNC if the need any syncing at all we enforce it's
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index b04f88eed09e..f35794b97e8e 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -92,7 +92,11 @@ static int fanotify_get_response_from_access(struct fsnotify_group *group,
 
         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);
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 063224812b7e..8b61220cffc5 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -106,20 +106,29 @@ static int create_fd(struct fsnotify_group *group, struct fsnotify_event *event)
         return client_fd;
 }
 
-static ssize_t fill_event_metadata(struct fsnotify_group *group,
+static int fill_event_metadata(struct fsnotify_group *group,
                                    struct fanotify_event_metadata *metadata,
                                    struct fsnotify_event *event)
 {
+        int ret = 0;
+
         pr_debug("%s: group=%p metadata=%p event=%p\n", __func__,
                  group, metadata, event);
 
         metadata->event_len = FAN_EVENT_METADATA_LEN;
+        metadata->metadata_len = FAN_EVENT_METADATA_LEN;
         metadata->vers = FANOTIFY_METADATA_VERSION;
         metadata->mask = event->mask & FAN_ALL_OUTGOING_EVENTS;
         metadata->pid = pid_vnr(event->tgid);
-        metadata->fd = create_fd(group, event);
+        if (unlikely(event->mask & FAN_Q_OVERFLOW))
+                metadata->fd = FAN_NOFD;
+        else {
+                metadata->fd = create_fd(group, event);
+                if (metadata->fd < 0)
+                        ret = metadata->fd;
+        }
 
-        return metadata->fd;
+        return ret;
 }
 
 #ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
@@ -200,7 +209,7 @@ static int prepare_for_access_response(struct fsnotify_group *group,
 
         mutex_lock(&group->fanotify_data.access_mutex);
 
-        if (group->fanotify_data.bypass_perm) {
+        if (atomic_read(&group->fanotify_data.bypass_perm)) {
                 mutex_unlock(&group->fanotify_data.access_mutex);
                 kmem_cache_free(fanotify_response_event_cache, re);
                 event->response = FAN_ALLOW;
@@ -257,24 +266,34 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
 
         pr_debug("%s: group=%p event=%p\n", __func__, group, event);
 
-        fd = fill_event_metadata(group, &fanotify_event_metadata, event);
-        if (fd < 0)
-                return fd;
+        ret = fill_event_metadata(group, &fanotify_event_metadata, event);
+        if (ret < 0)
+                goto out;
 
+        fd = fanotify_event_metadata.fd;
         ret = prepare_for_access_response(group, event, fd);
         if (ret)
                 goto out_close_fd;
 
         ret = -EFAULT;
-        if (copy_to_user(buf, &fanotify_event_metadata, FAN_EVENT_METADATA_LEN))
+        if (copy_to_user(buf, &fanotify_event_metadata,
+                         fanotify_event_metadata.event_len))
                 goto out_kill_access_response;
 
-        return FAN_EVENT_METADATA_LEN;
+        return fanotify_event_metadata.event_len;
 
 out_kill_access_response:
         remove_access_response(group, event, fd);
 out_close_fd:
-        sys_close(fd);
+        if (fd != FAN_NOFD)
+                sys_close(fd);
+out:
+#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
+        if (event->mask & FAN_ALL_PERM_EVENTS) {
+                event->response = FAN_DENY;
+                wake_up(&group->fanotify_data.access_waitq);
+        }
+#endif
         return ret;
 }
 
@@ -382,7 +401,7 @@ static int fanotify_release(struct inode *ignored, struct file *file)
 
         mutex_lock(&group->fanotify_data.access_mutex);
 
-        group->fanotify_data.bypass_perm = true;
+        atomic_inc(&group->fanotify_data.bypass_perm);
 
         list_for_each_entry_safe(re, lre, &group->fanotify_data.access_list, list) {
                 pr_debug("%s: found group=%p re=%p event=%p\n", __func__, group,
@@ -586,11 +605,10 @@ static int fanotify_add_vfsmount_mark(struct fsnotify_group *group,
 {
         struct fsnotify_mark *fsn_mark;
         __u32 added;
+        int ret = 0;
 
         fsn_mark = fsnotify_find_vfsmount_mark(group, mnt);
         if (!fsn_mark) {
-                int ret;
-
                 if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks)
                         return -ENOSPC;
 
@@ -600,17 +618,16 @@ static int fanotify_add_vfsmount_mark(struct fsnotify_group *group,
 
                 fsnotify_init_mark(fsn_mark, fanotify_free_mark);
                 ret = fsnotify_add_mark(fsn_mark, group, NULL, mnt, 0);
-                if (ret) {
-                        fanotify_free_mark(fsn_mark);
-                        return ret;
-                }
+                if (ret)
+                        goto err;
         }
         added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
-        fsnotify_put_mark(fsn_mark);
+
         if (added & ~mnt->mnt_fsnotify_mask)
                 fsnotify_recalc_vfsmount_mask(mnt);
-
-        return 0;
+err:
+        fsnotify_put_mark(fsn_mark);
+        return ret;
 }
 
 static int fanotify_add_inode_mark(struct fsnotify_group *group,
@@ -619,6 +636,7 @@ static int fanotify_add_inode_mark(struct fsnotify_group *group,
 {
         struct fsnotify_mark *fsn_mark;
         __u32 added;
+        int ret = 0;
 
         pr_debug("%s: group=%p inode=%p\n", __func__, group, inode);
 
@@ -634,8 +652,6 @@ static int fanotify_add_inode_mark(struct fsnotify_group *group,
 
         fsn_mark = fsnotify_find_inode_mark(group, inode);
         if (!fsn_mark) {
-                int ret;
-
                 if (atomic_read(&group->num_marks) > group->fanotify_data.max_marks)
                         return -ENOSPC;
 
@@ -645,16 +661,16 @@ static int fanotify_add_inode_mark(struct fsnotify_group *group,
 
                 fsnotify_init_mark(fsn_mark, fanotify_free_mark);
                 ret = fsnotify_add_mark(fsn_mark, group, inode, NULL, 0);
-                if (ret) {
-                        fanotify_free_mark(fsn_mark);
-                        return ret;
-                }
+                if (ret)
+                        goto err;
         }
         added = fanotify_mark_add_to_mask(fsn_mark, mask, flags);
-        fsnotify_put_mark(fsn_mark);
+
         if (added & ~inode->i_fsnotify_mask)
                 fsnotify_recalc_inode_mask(inode);
-        return 0;
+err:
+        fsnotify_put_mark(fsn_mark);
+        return ret;
 }
 
 /* fanotify syscalls */
@@ -687,8 +703,10 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
 
         /* fsnotify_alloc_group takes a ref.  Dropped in fanotify_release */
         group = fsnotify_alloc_group(&fanotify_fsnotify_ops);
-        if (IS_ERR(group))
+        if (IS_ERR(group)) {
+                free_uid(user);
                 return PTR_ERR(group);
+        }
 
         group->fanotify_data.user = user;
         atomic_inc(&user->fanotify_listeners);
@@ -698,6 +716,7 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
         mutex_init(&group->fanotify_data.access_mutex);
         init_waitqueue_head(&group->fanotify_data.access_waitq);
         INIT_LIST_HEAD(&group->fanotify_data.access_list);
+        atomic_set(&group->fanotify_data.bypass_perm, 0);
 #endif
         switch (flags & FAN_ALL_CLASS_BITS) {
         case FAN_CLASS_NOTIF:
@@ -764,8 +783,10 @@ SYSCALL_DEFINE(fanotify_mark)(int fanotify_fd, unsigned int flags,
         if (flags & ~FAN_ALL_MARK_FLAGS)
                 return -EINVAL;
         switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) {
-        case FAN_MARK_ADD:
+        case FAN_MARK_ADD:              /* fallthrough */
         case FAN_MARK_REMOVE:
+                if (!mask)
+                        return -EINVAL;
         case FAN_MARK_FLUSH:
                 break;
         default:
diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index 444c305a468c..4cd5d5d78f9f 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -752,6 +752,7 @@ SYSCALL_DEFINE1(inotify_init1, int, flags)
         if (ret >= 0)
                 return ret;
 
+        fsnotify_put_group(group);
         atomic_dec(&user->inotify_devs);
 out_free_uid:
         free_uid(user);
diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h
index 0f0121467fc4..6c6133f76e16 100644
--- a/include/linux/fanotify.h
+++ b/include/linux/fanotify.h
@@ -83,11 +83,13 @@
                                  FAN_ALL_PERM_EVENTS |\
                                  FAN_Q_OVERFLOW)
 
-#define FANOTIFY_METADATA_VERSION       2
+#define FANOTIFY_METADATA_VERSION       3
 
 struct fanotify_event_metadata {
         __u32 event_len;
-        __u32 vers;
+        __u8 vers;
+        __u8 reserved;
+        __u16 metadata_len;
         __aligned_u64 mask;
         __s32 fd;
         __s32 pid;
@@ -96,11 +98,13 @@ struct fanotify_event_metadata {
 struct fanotify_response {
         __s32 fd;
         __u32 response;
-} __attribute__ ((packed));
+};
 
 /* Legit userspace responses to a _PERM event */
 #define FAN_ALLOW       0x01
 #define FAN_DENY        0x02
+/* No fd set in event */
+#define FAN_NOFD        -1
 
 /* Helper functions to deal with fanotify_event_metadata buffers */
 #define FAN_EVENT_METADATA_LEN (sizeof(struct fanotify_event_metadata))
diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index 5c185fa27089..b10bcdeaef76 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -235,9 +235,6 @@ static inline void fsnotify_open(struct file *file)
         if (S_ISDIR(inode->i_mode))
                 mask |= FS_ISDIR;
 
-        /* FMODE_NONOTIFY must never be set from user */
-        file->f_mode &= ~FMODE_NONOTIFY;
-
         fsnotify_parent(path, NULL, mask);
         fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
 }
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index 0a68f924f06f..7380763595d3 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -166,7 +166,7 @@ struct fsnotify_group {
                         struct mutex access_mutex;
                         struct list_head access_list;
                         wait_queue_head_t access_waitq;
-                        bool bypass_perm; /* protected by access_mutex */
+                        atomic_t bypass_perm;
 #endif /* CONFIG_FANOTIFY_ACCESS_PERMISSIONS */
                         int f_flags;
                         unsigned int max_marks;