Merge tag 'fsnotify_for_v4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs

Pull fsnotify updates from Jan Kara:
 "Support for new FAN_OPEN_EXEC event and couple of cleanups around
  fsnotify"

* tag 'fsnotify_for_v4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
  fanotify: Use inode_is_open_for_write
  fanotify: Make sure to check event_len when copying
  fsnotify/fdinfo: include fdinfo.h for inotify_show_fdinfo()
  fanotify: introduce new event mask FAN_OPEN_EXEC_PERM
  fsnotify: refactor fsnotify_parent()/fsnotify() paired calls when event is on path
  fanotify: introduce new event mask FAN_OPEN_EXEC
  fanotify: return only user requested event types in event mask

fs/notify/fanotify/fanotify.c

@@ -89,7 +89,13 @@ static int fanotify_get_response(struct fsnotify_group *group,
 	return ret;
 }
 
-static bool fanotify_should_send_event(struct fsnotify_iter_info *iter_info,
+/*
+ * This function returns a mask for an event that only contains the flags
+ * that have been specifically requested by the user. Flags that may have
+ * been included within the event mask, but have not been explicitly
+ * requested by the user, will not be present in the returned mask.
+ */
+static u32 fanotify_group_event_mask(struct fsnotify_iter_info *iter_info,
 				       u32 event_mask, const void *data,
 				       int data_type)
 {
@@ -101,14 +107,14 @@ static bool fanotify_should_send_event(struct fsnotify_iter_info *iter_info,
 	pr_debug("%s: report_mask=%x mask=%x data=%p data_type=%d\n",
 		 __func__, iter_info->report_mask, event_mask, data, data_type);
 
-	/* if we don't have enough info to send an event to userspace say no */
+	/* If we don't have enough info to send an event to userspace say no */
 	if (data_type != FSNOTIFY_EVENT_PATH)
-		return false;
+		return 0;
 
-	/* sorry, fanotify only gives a damn about files and dirs */
+	/* Sorry, fanotify only gives a damn about files and dirs */
 	if (!d_is_reg(path->dentry) &&
 	    !d_can_lookup(path->dentry))
-		return false;
+		return 0;
 
 	fsnotify_foreach_obj_type(type) {
 		if (!fsnotify_iter_should_report_type(iter_info, type))
@@ -129,13 +135,10 @@ static bool fanotify_should_send_event(struct fsnotify_iter_info *iter_info,
 
 	if (d_is_dir(path->dentry) &&
 	    !(marks_mask & FS_ISDIR & ~marks_ignored_mask))
-		return false;
-
-	if (event_mask & FANOTIFY_OUTGOING_EVENTS &
-	    marks_mask & ~marks_ignored_mask)
-		return true;
+		return 0;
 
-	return false;
+	return event_mask & FANOTIFY_OUTGOING_EVENTS & marks_mask &
+		~marks_ignored_mask;
 }
 
 struct fanotify_event_info *fanotify_alloc_event(struct fsnotify_group *group,
@@ -207,10 +210,13 @@ static int fanotify_handle_event(struct fsnotify_group *group,
 	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);
+	BUILD_BUG_ON(FAN_OPEN_EXEC != FS_OPEN_EXEC);
+	BUILD_BUG_ON(FAN_OPEN_EXEC_PERM != FS_OPEN_EXEC_PERM);
 
-	BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 10);
+	BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 12);
 
-	if (!fanotify_should_send_event(iter_info, mask, data, data_type))
+	mask = fanotify_group_event_mask(iter_info, mask, data, data_type);
+	if (!mask)
 		return 0;
 
 	pr_debug("%s: group=%p inode=%p mask=%x\n", __func__, group, inode,

fs/notify/fanotify/fanotify_user.c

@@ -206,7 +206,7 @@ static int process_access_response(struct fsnotify_group *group,
 
 static ssize_t copy_event_to_user(struct fsnotify_group *group,
 				  struct fsnotify_event *event,
-				  char __user *buf)
+				  char __user *buf, size_t count)
 {
 	struct fanotify_event_metadata fanotify_event_metadata;
 	struct file *f;
@@ -220,6 +220,12 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
 
 	fd = fanotify_event_metadata.fd;
 	ret = -EFAULT;
+	/*
+	 * Sanity check copy size in case get_one_event() and
+	 * fill_event_metadata() event_len sizes ever get out of sync.
+	 */
+	if (WARN_ON_ONCE(fanotify_event_metadata.event_len > count))
+		goto out_close_fd;
 	if (copy_to_user(buf, &fanotify_event_metadata,
 			 fanotify_event_metadata.event_len))
 		goto out_close_fd;
@@ -295,7 +301,7 @@ static ssize_t fanotify_read(struct file *file, char __user *buf,
 			continue;
 		}
 
-		ret = copy_event_to_user(group, kevent, buf);
+		ret = copy_event_to_user(group, kevent, buf, count);
 		if (unlikely(ret == -EOPENSTALE)) {
 			/*
 			 * We cannot report events with stale fd so drop it.
@@ -669,7 +675,7 @@ static int fanotify_add_inode_mark(struct fsnotify_group *group,
 	 */
 	if ((flags & FAN_MARK_IGNORED_MASK) &&
 	    !(flags & FAN_MARK_IGNORED_SURV_MODIFY) &&
-	    (atomic_read(&inode->i_writecount) > 0))
+	    inode_is_open_for_write(inode))
 		return 0;
 
 	return fanotify_add_mark(group, &inode->i_fsnotify_marks,

fs/notify/fdinfo.c

@@ -15,6 +15,7 @@
 #include <linux/exportfs.h>
 
 #include "inotify/inotify.h"
+#include "fdinfo.h"
 #include "fsnotify.h"
 
 #if defined(CONFIG_PROC_FS)

fs/notify/fsnotify.c

@@ -401,7 +401,7 @@ static __init int fsnotify_init(void)
 {
 	int ret;
 
-	BUILD_BUG_ON(HWEIGHT32(ALL_FSNOTIFY_BITS) != 23);
+	BUILD_BUG_ON(HWEIGHT32(ALL_FSNOTIFY_BITS) != 25);
 
 	ret = init_srcu_struct(&fsnotify_mark_srcu);
 	if (ret)

include/linux/fanotify.h

@@ -37,10 +37,11 @@
 
 /* Events that user can request to be notified on */
 #define FANOTIFY_EVENTS		(FAN_ACCESS | FAN_MODIFY | \
-				 FAN_CLOSE | FAN_OPEN)
+				 FAN_CLOSE | FAN_OPEN | FAN_OPEN_EXEC)
 
 /* Events that require a permission response from user */
-#define FANOTIFY_PERM_EVENTS	(FAN_OPEN_PERM | FAN_ACCESS_PERM)
+#define FANOTIFY_PERM_EVENTS	(FAN_OPEN_PERM | FAN_ACCESS_PERM | \
+				 FAN_OPEN_EXEC_PERM)
 
 /* Extra flags that may be reported with event or control handling of events */
 #define FANOTIFY_EVENT_FLAGS	(FAN_EVENT_ON_CHILD | FAN_ONDIR)

include/linux/fsnotify.h

@@ -26,30 +26,46 @@ static inline int fsnotify_parent(const struct path *path, struct dentry *dentry
 	return __fsnotify_parent(path, dentry, mask);
 }
 
-/* simple call site for access decisions */
+/*
+ * Simple wrapper to consolidate calls fsnotify_parent()/fsnotify() when
+ * an event is on a path.
+ */
+static inline int fsnotify_path(struct inode *inode, const struct path *path,
+				__u32 mask)
+{
+	int ret = fsnotify_parent(path, NULL, mask);
+
+	if (ret)
+		return ret;
+	return fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
+}
+
+/* Simple call site for access decisions */
 static inline int fsnotify_perm(struct file *file, int mask)
 {
+	int ret;
 	const struct path *path = &file->f_path;
 	struct inode *inode = file_inode(file);
 	__u32 fsnotify_mask = 0;
-	int ret;
 
 	if (file->f_mode & FMODE_NONOTIFY)
 		return 0;
 	if (!(mask & (MAY_READ | MAY_OPEN)))
 		return 0;
-	if (mask & MAY_OPEN)
+	if (mask & MAY_OPEN) {
 		fsnotify_mask = FS_OPEN_PERM;
-	else if (mask & MAY_READ)
-		fsnotify_mask = FS_ACCESS_PERM;
-	else
-		BUG();
 
-	ret = fsnotify_parent(path, NULL, fsnotify_mask);
+		if (file->f_flags & __FMODE_EXEC) {
+			ret = fsnotify_path(inode, path, FS_OPEN_EXEC_PERM);
+
 			if (ret)
 				return ret;
+		}
+	} else if (mask & MAY_READ) {
+		fsnotify_mask = FS_ACCESS_PERM;
+	}
 
-	return fsnotify(inode, fsnotify_mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
+	return fsnotify_path(inode, path, fsnotify_mask);
 }
 
 /*
@@ -180,10 +196,8 @@ static inline void fsnotify_access(struct file *file)
 	if (S_ISDIR(inode->i_mode))
 		mask |= FS_ISDIR;
 
-	if (!(file->f_mode & FMODE_NONOTIFY)) {
-		fsnotify_parent(path, NULL, mask);
-		fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
-	}
+	if (!(file->f_mode & FMODE_NONOTIFY))
+		fsnotify_path(inode, path, mask);
 }
 
 /*
@@ -198,10 +212,8 @@ static inline void fsnotify_modify(struct file *file)
 	if (S_ISDIR(inode->i_mode))
 		mask |= FS_ISDIR;
 
-	if (!(file->f_mode & FMODE_NONOTIFY)) {
-		fsnotify_parent(path, NULL, mask);
-		fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
-	}
+	if (!(file->f_mode & FMODE_NONOTIFY))
+		fsnotify_path(inode, path, mask);
 }
 
 /*
@@ -215,9 +227,10 @@ static inline void fsnotify_open(struct file *file)
 
 	if (S_ISDIR(inode->i_mode))
 		mask |= FS_ISDIR;
+	if (file->f_flags & __FMODE_EXEC)
+		mask |= FS_OPEN_EXEC;
 
-	fsnotify_parent(path, NULL, mask);
-	fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
+	fsnotify_path(inode, path, mask);
 }
 
 /*
@@ -233,10 +246,8 @@ static inline void fsnotify_close(struct file *file)
 	if (S_ISDIR(inode->i_mode))
 		mask |= FS_ISDIR;
 
-	if (!(file->f_mode & FMODE_NONOTIFY)) {
-		fsnotify_parent(path, NULL, mask);
-		fsnotify(inode, mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
-	}
+	if (!(file->f_mode & FMODE_NONOTIFY))
+		fsnotify_path(inode, path, mask);
 }
 
 /*

include/linux/fsnotify_backend.h

@@ -38,6 +38,7 @@
 #define FS_DELETE		0x00000200	/* Subfile was deleted */
 #define FS_DELETE_SELF		0x00000400	/* Self was deleted */
 #define FS_MOVE_SELF		0x00000800	/* Self was moved */
+#define FS_OPEN_EXEC		0x00001000	/* File was opened for exec */
 
 #define FS_UNMOUNT		0x00002000	/* inode on umount fs */
 #define FS_Q_OVERFLOW		0x00004000	/* Event queued overflowed */
@@ -45,6 +46,7 @@
 
 #define FS_OPEN_PERM		0x00010000	/* open event in an permission hook */
 #define FS_ACCESS_PERM		0x00020000	/* access event in a permissions hook */
+#define FS_OPEN_EXEC_PERM	0x00040000	/* open/exec event in a permission hook */
 
 #define FS_EXCL_UNLINK		0x04000000	/* do not send events if object is unlinked */
 #define FS_ISDIR		0x40000000	/* event occurred against dir */
@@ -62,11 +64,13 @@
 #define FS_EVENTS_POSS_ON_CHILD   (FS_ACCESS | FS_MODIFY | FS_ATTRIB |\
 				   FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | FS_OPEN |\
 				   FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE |\
-				   FS_DELETE | FS_OPEN_PERM | FS_ACCESS_PERM)
+				   FS_DELETE | FS_OPEN_PERM | FS_ACCESS_PERM | \
+				   FS_OPEN_EXEC | FS_OPEN_EXEC_PERM)
 
 #define FS_MOVE			(FS_MOVED_FROM | FS_MOVED_TO)
 
-#define ALL_FSNOTIFY_PERM_EVENTS (FS_OPEN_PERM | FS_ACCESS_PERM)
+#define ALL_FSNOTIFY_PERM_EVENTS (FS_OPEN_PERM | FS_ACCESS_PERM | \
+				  FS_OPEN_EXEC_PERM)
 
 /* Events that can be reported to backends */
 #define ALL_FSNOTIFY_EVENTS (FS_ACCESS | FS_MODIFY | FS_ATTRIB | \
@@ -74,7 +78,8 @@
 			     FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE | \
 			     FS_DELETE | FS_DELETE_SELF | FS_MOVE_SELF | \
 			     FS_UNMOUNT | FS_Q_OVERFLOW | FS_IN_IGNORED | \
-			     FS_OPEN_PERM | FS_ACCESS_PERM | FS_DN_RENAME)
+			     FS_OPEN_PERM | FS_ACCESS_PERM | FS_DN_RENAME | \
+			     FS_OPEN_EXEC | FS_OPEN_EXEC_PERM)
 
 /* Extra flags that may be reported with event or control handling of events */
 #define ALL_FSNOTIFY_FLAGS  (FS_EXCL_UNLINK | FS_ISDIR | FS_IN_ONESHOT | \

include/uapi/linux/fanotify.h

@@ -10,11 +10,13 @@
 #define FAN_CLOSE_WRITE		0x00000008	/* Writtable file closed */
 #define FAN_CLOSE_NOWRITE	0x00000010	/* Unwrittable file closed */
 #define FAN_OPEN		0x00000020	/* File was opened */
+#define FAN_OPEN_EXEC		0x00001000	/* File was opened for exec */
 
 #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 */
+#define FAN_OPEN_EXEC_PERM	0x00040000	/* File open/exec in perm check */
 
 #define FAN_ONDIR		0x40000000	/* event occurred against dir */