From: Ian Kent <raven@themaw.net>
Date: Sat, 10 Sep 2016 10:34:25 +0000 (+1000)
Subject: autofs: fix dev ioctl number range check
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=72f2e85ecf0ae2a40b857dfb858126c79265a99c;p=deliverable%2Flinux.git

autofs: fix dev ioctl number range check

The count of miscellaneous device ioctls in fs/autofs4/autofs_i.h is wrong.

The number of ioctls is the difference between AUTOFS_DEV_IOCTL_VERSION_CMD
and AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD (14) not the difference between
AUTOFS_IOC_COUNT and 11 (21).

Link: http://lkml.kernel.org/r/20160812024841.12352.11975.stgit@pluto.themaw.net
Signed-off-by: Ian Kent <raven@themaw.net>
Cc: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/fs/autofs4/autofs_i.h b/fs/autofs4/autofs_i.h
index 73e3d3810e3f..dd71bd4ff903 100644
--- a/fs/autofs4/autofs_i.h
+++ b/fs/autofs4/autofs_i.h
@@ -20,7 +20,8 @@
 #define AUTOFS_IOC_COUNT     32
 
 #define AUTOFS_DEV_IOCTL_IOC_FIRST	(AUTOFS_DEV_IOCTL_VERSION)
-#define AUTOFS_DEV_IOCTL_IOC_COUNT	(AUTOFS_IOC_COUNT - 11)
+#define AUTOFS_DEV_IOCTL_IOC_COUNT \
+	(AUTOFS_DEV_IOCTL_VERSION_CMD - AUTOFS_DEV_IOCTL_ISMOUNTPOINT_CMD)
 
 #include <linux/kernel.h>
 #include <linux/slab.h>
diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c
index d47b35a669e1..13e75177f892 100644
--- a/fs/autofs4/dev-ioctl.c
+++ b/fs/autofs4/dev-ioctl.c
@@ -642,7 +642,7 @@ static int _autofs_dev_ioctl(unsigned int command,
 	cmd = _IOC_NR(command);
 
 	if (_IOC_TYPE(command) != _IOC_TYPE(AUTOFS_DEV_IOCTL_IOC_FIRST) ||
-	    cmd - cmd_first >= AUTOFS_DEV_IOCTL_IOC_COUNT) {
+	    cmd - cmd_first > AUTOFS_DEV_IOCTL_IOC_COUNT) {
 		return -ENOTTY;
 	}