[PATCH v6 4/4] fsnotify: don't merge events FS_OPEN_PERM and FS_OPEN_EXEC_PERM

[Matthew Bobrowski <mbobrowski@xxxxxxxxxxxxxx>]

Permission events are not to be consolidated into a single event mask.
In order for this to not happen, we require additional calls to
fsnotify_parent() and fsnotify() within the fsnotify_perm() when the
conditon to set FS_OPEN_EXEC_PERM is evaluated to true.

To simplify the code that provides this functionality a simple wrapper
fsnotify_path() has been defined to keep things nice and clean. Other
functions that used the same fsnotify_parent()/fsnotify() call
combination have been updated to use the simplified fsnotify_path()
wrapper.

Signed-off-by: Matthew Bobrowski <mbobrowski@xxxxxxxxxxxxxx>
---
 include/linux/fsnotify.h | 48 ++++++++++++++++++++++------------------
 1 file changed, 27 insertions(+), 21 deletions(-)

diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index 9c7b594bf540..660ffc751352 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -26,6 +26,21 @@ static inline int fsnotify_parent(const struct path *path, struct dentry *dentry
 	return __fsnotify_parent(path, dentry, mask);
 }
 
+/*
+ * 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;
+
+	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)
 {
@@ -41,17 +56,15 @@ static inline int fsnotify_perm(struct file *file, int mask)
 	if (mask & MAY_OPEN) {
 		fsnotify_mask = FS_OPEN_PERM;
 
-		if (file->f_flags & __FMODE_EXEC)
-			fsnotify_mask |= FS_OPEN_EXEC_PERM;
+		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;
 	}
 
-	ret = fsnotify_parent(path, NULL, fsnotify_mask);
-	if (ret)
-		return ret;
-
-	return fsnotify(inode, fsnotify_mask, path, FSNOTIFY_EVENT_PATH, NULL, 0);
+	return fsnotify_path(inode, path, fsnotify_mask);
 }
 
 /*
@@ -182,10 +195,8 @@ 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);
 }
 
 /*
@@ -200,10 +211,8 @@ 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);
 }
 
 /*
@@ -220,8 +229,7 @@ static inline void fsnotify_open(struct file *file)
 	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);
 }
 
 /*
@@ -237,10 +245,8 @@ 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);
 }
 
 /*
-- 
2.17.2


-- 
Matthew Bobrowski