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authorMatthew Wilcox <willy@infradead.org>2020-10-15 20:13:08 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-16 11:11:22 -0700
commit589f6b52682542c1b230c435e1de679755f3332a (patch)
tree701c254c643a11e7f2f3dc2b252d4d0902d0cf36 /fs/autofs/dev-ioctl.c
parent50b7d85680086126d7bd91dae81d57d4cb1ab6b7 (diff)
downloadlinux-589f6b52682542c1b230c435e1de679755f3332a.tar.bz2
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>
Diffstat (limited to 'fs/autofs/dev-ioctl.c')
-rw-r--r--fs/autofs/dev-ioctl.c8
1 files changed, 6 insertions, 2 deletions
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 @@ 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(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 */