[PATCH 6.1 001/143] 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
@@ -642,6 +642,7 @@ static struct file *pick_file(struct fil
 	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);