fanotify: permissions and blocking
This is the backend work needed for fanotify to support the new
FS_OPEN_PERM and FS_ACCESS_PERM fsnotify events. This is done using the
new fsnotify secondary queue. No userspace interface is provided actually
respond to or request these events.
Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h
index 385896c..02f8067 100644
--- a/include/linux/fanotify.h
+++ b/include/linux/fanotify.h
@@ -15,6 +15,9 @@
/* FIXME currently Q's have no limit.... */
#define FAN_Q_OVERFLOW 0x00004000 /* Event queued overflowed */
+#define FAN_OPEN_PERM 0x00010000 /* File open in perm check */
+#define FAN_ACCESS_PERM 0x00020000 /* File accessed in perm check */
+
/* helper events */
#define FAN_CLOSE (FAN_CLOSE_WRITE | FAN_CLOSE_NOWRITE) /* close */
@@ -52,7 +55,14 @@
FAN_CLOSE |\
FAN_OPEN)
+/*
+ * All events which require a permission response from userspace
+ */
+#define FAN_ALL_PERM_EVENTS (FAN_OPEN_PERM |\
+ FAN_ACCESS_PERM)
+
#define FAN_ALL_OUTGOING_EVENTS (FAN_ALL_EVENTS |\
+ FAN_ALL_PERM_EVENTS |\
FAN_Q_OVERFLOW)
#define FANOTIFY_METADATA_VERSION 1
@@ -65,6 +75,10 @@
__s64 pid;
} __attribute__ ((packed));
+/* Legit userspace responses to a _PERM event */
+#define FAN_ALLOW 0x01
+#define FAN_DENY 0x02
+
/* Helper functions to deal with fanotify_event_metadata buffers */
#define FAN_EVENT_METADATA_LEN (sizeof(struct fanotify_event_metadata))
@@ -78,5 +92,9 @@
#ifdef __KERNEL__
+struct fanotify_wait {
+ struct fsnotify_event *event;
+ __s32 fd;
+};
#endif /* __KERNEL__ */
#endif /* _LINUX_FANOTIFY_H */
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
index c34728e..b0d00fd 100644
--- a/include/linux/fsnotify_backend.h
+++ b/include/linux/fsnotify_backend.h
@@ -160,6 +160,14 @@
struct user_struct *user;
} inotify_data;
#endif
+#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
+ struct fanotify_group_private_data {
+ /* allows a group to block waiting for a userspace response */
+ struct mutex access_mutex;
+ struct list_head access_list;
+ wait_queue_head_t access_waitq;
+ } fanotify_data;
+#endif
};
};
@@ -227,6 +235,10 @@
size_t name_len;
struct pid *tgid;
+#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
+ __u32 response; /* userspace answer to question */
+#endif /* CONFIG_FANOTIFY_ACCESS_PERMISSIONS */
+
struct list_head private_data_list; /* groups can store private data here */
};