The patch titled
Subject: autofs: harden ioctl table
has been added to the -mm tree. Its filename is
harden-autofs-ioctl-table.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/harden-autofs-ioctl-table.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/harden-autofs-ioctl-table.patch
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------------------------------------------------------
From: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Subject: 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.
Link: https://lkml.kernel.org/r/20200818122203.GO17456@xxxxxxxxxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Acked-by: Ian Kent <raven@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/autofs/dev-ioctl.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
--- a/fs/autofs/dev-ioctl.c~harden-autofs-ioctl-table
+++ a/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 @@ out:
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(unsigne
};
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 */
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-debug-do-not-dereference-i_ino-blindly.patch
mm-account-pmd-tables-like-pte-tables.patch
harden-autofs-ioctl-table.patch
