[PATCH 5.4 01/68] fs: prevent out-of-bounds array speculation when closing a file descriptor

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

From: Theodore Ts'o <tytso@xxxxxxx>

commit 609d54441493c99f21c1823dfd66fa7f4c512ff4 upstream.

Google-Bug-Id: 114199369
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/file.c |    1 +
 1 file changed, 1 insertion(+)

--- a/fs/file.c
+++ b/fs/file.c
@@ -654,6 +654,7 @@ int __close_fd_get_file(unsigned int fd,
 	fdt = files_fdtable(files);
 	if (fd >= fdt->max_fds)
 		goto out_unlock;
+	fd = array_index_nospec(fd, fdt->max_fds);
 	file = fdt->fd[fd];
 	if (!file)
 		goto out_unlock;