inotify: Use strscpy() for event->name copies

Since we have already allocated "len + 1" space for event->name, make sure
that name->name cannot ever accidentally cause a copy overflow by calling
strscpy() instead of the unbounded strcpy() routine. This assists in
the ongoing efforts to remove the unsafe strcpy() API[1] from the kernel.

Link: KSPP#88 [1]
Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20241216224507.work.859-kees@kernel.org

Author: kees

fs/notify/inotify/inotify_fsnotify.c

@@ -121,7 +121,7 @@ int inotify_handle_inode_event(struct fsnotify_mark *inode_mark, u32 mask,
 	event->sync_cookie = cookie;
 	event->name_len = len;
 	if (len)
-		strcpy(event->name, name->name);
+		strscpy(event->name, name->name, event->name_len + 1);
 
 	ret = fsnotify_add_event(group, fsn_event, inotify_merge);
 	if (ret) {