From: Theodore Ts'o <tytso@mit.edu>
Date: Mon, 6 Mar 2023 18:54:50 +0000 (-0500)
Subject: fs: prevent out-of-bounds array speculation when closing a file descriptor
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=f8cd8754a03a3748384ee438c572423643c9c315;p=linux.git

fs: prevent out-of-bounds array speculation when closing a file descriptor

commit 609d54441493c99f21c1823dfd66fa7f4c512ff4 upstream.

Google-Bug-Id: 114199369
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/file.c b/fs/file.c
index 214364e19d76f..ee1c350ec58a2 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -646,6 +646,7 @@ static struct file *pick_file(struct files_struct *files, unsigned fd)
 		file = ERR_PTR(-EINVAL);
 		goto out_unlock;
 	}
+	fd = array_index_nospec(fd, fdt->max_fds);
 	file = fdt->fd[fd];
 	if (!file) {
 		file = ERR_PTR(-EBADF);