From 609d54441493c99f21c1823dfd66fa7f4c512ff4 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Mon, 6 Mar 2023 13:54:50 -0500
Subject: [PATCH] fs: prevent out-of-bounds array speculation when closing a
 file descriptor

Google-Bug-Id: 114199369
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 fs/file.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/file.c b/fs/file.c
index c942c89ca4cd..7893ea161d77 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -642,6 +642,7 @@ static struct file *pick_file(struct files_struct *files, unsigned fd)
 	if (fd >= fdt->max_fds)
 		return NULL;
 
+	fd = array_index_nospec(fd, fdt->max_fds);
 	file = fdt->fd[fd];
 	if (file) {
 		rcu_assign_pointer(fdt->fd[fd], NULL);