Commit 589f6b526825 for kernel

commit 589f6b52682542c1b230c435e1de679755f3332a
Author: Matthew Wilcox <willy@infradead.org>
Date:   Thu Oct 15 20:13:08 2020 -0700

    autofs: harden ioctl table

    The table of ioctl functions should be marked const in order to put them
    in read-only memory, and we should use array_index_nospec() to avoid
    speculation disclosing the contents of kernel memory to userspace.

    Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
    Acked-by: Ian Kent <raven@themaw.net>
    Link: https://lkml.kernel.org/r/20200818122203.GO17456@casper.infradead.org
    Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/autofs/dev-ioctl.c b/fs/autofs/dev-ioctl.c
index 75105f45c51a..322b7dfb4ea0 100644
--- a/fs/autofs/dev-ioctl.c
+++ b/fs/autofs/dev-ioctl.c
@@ -8,6 +8,7 @@
 #include <linux/compat.h>
 #include <linux/syscalls.h>
 #include <linux/magic.h>
+#include <linux/nospec.h>

 #include "autofs_i.h"

@@ -563,7 +564,7 @@ static int autofs_dev_ioctl_ismountpoint(struct file *fp,

 static ioctl_fn lookup_dev_ioctl(unsigned int cmd)
 {
-	static ioctl_fn _ioctls[] = {
+	static const ioctl_fn _ioctls[] = {
 		autofs_dev_ioctl_version,
 		autofs_dev_ioctl_protover,
 		autofs_dev_ioctl_protosubver,
@@ -581,7 +582,10 @@ static ioctl_fn lookup_dev_ioctl(unsigned int cmd)
 	};
 	unsigned int idx = cmd_idx(cmd);

-	return (idx >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[idx];
+	if (idx >= ARRAY_SIZE(_ioctls))
+		return NULL;
+	idx = array_index_nospec(idx, ARRAY_SIZE(_ioctls));
+	return _ioctls[idx];
 }

 /* ioctl dispatcher */