Linux compat: Grsecurity kernel

API Change: Module parameter set/get methods take const parameter in
Grsecurity kernel v4.7.1

Signed-off-by: Gvozden Neskovic <neskovic@gmail.com>
Signed-off-by: Jason Zaman <jason@perfinion.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #4997
Closes #5001

config/kernel-mod-param.m4

@@ -0,0 +1,30 @@
+dnl #
+dnl # Grsecurity kernel API change
+dnl # constified parameters of module_param_call() methods
+dnl #
+AC_DEFUN([ZFS_AC_KERNEL_MODULE_PARAM_CALL_CONST], [
+	AC_MSG_CHECKING([whether module_param_call() is hardened])
+	ZFS_LINUX_TRY_COMPILE([
+		#include <linux/module.h>
+		#include <linux/moduleparam.h>
+
+		int param_get(char *b, const struct kernel_param *kp)
+		{
+			return (0);
+		}
+
+		int param_set(const char *b, const struct kernel_param *kp)
+		{
+			return (0);
+		}
+
+		module_param_call(p, param_set, param_get, NULL, 0644);
+	],[
+	],[
+		AC_MSG_RESULT(yes)
+		AC_DEFINE(MODULE_PARAM_CALL_CONST, 1,
+		    [hardened module_param_call])
+	],[
+		AC_MSG_RESULT(no)
+	])
+])

config/kernel.m4

@@ -101,6 +101,7 @@ AC_DEFUN([ZFS_AC_CONFIG_KERNEL], [
 	ZFS_AC_KERNEL_GENERIC_IO_ACCT
 	ZFS_AC_KERNEL_FPU
 	ZFS_AC_KERNEL_KUID_HELPERS
+	ZFS_AC_KERNEL_MODULE_PARAM_CALL_CONST
 
 	AS_IF([test "$LINUX_OBJ" != "$LINUX"], [
 		KERNELMAKE_PARAMS="$KERNELMAKE_PARAMS O=$LINUX_OBJ"

include/linux/Makefile.am

@@ -7,7 +7,8 @@ KERNEL_H = \
 	$(top_srcdir)/include/linux/blkdev_compat.h \
 	$(top_srcdir)/include/linux/utsname_compat.h \
 	$(top_srcdir)/include/linux/kmap_compat.h \
-	$(top_srcdir)/include/linux/simd_x86.h
+	$(top_srcdir)/include/linux/simd_x86.h \
+	$(top_srcdir)/include/linux/mod_compat.h
 
 USER_H =
 

include/linux/mod_compat.h

@@ -0,0 +1,39 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright (C) 2016 Gvozden Neskovic <neskovic@gmail.com>.
+ */
+
+#ifndef _MOD_COMPAT_H
+#define	_MOD_COMPAT_H
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+
+/* Grsecurity kernel API change */
+#ifdef MODULE_PARAM_CALL_CONST
+typedef const struct kernel_param zfs_kernel_param_t;
+#else
+typedef struct kernel_param zfs_kernel_param_t;
+#endif
+
+#endif	/* _MOD_COMPAT_H */

module/zcommon/zfs_fletcher.c

@@ -653,9 +653,10 @@ fletcher_4_fini(void)
 }
 
 #if defined(_KERNEL) && defined(HAVE_SPL)
+#include <linux/mod_compat.h>
 
 static int
-fletcher_4_param_get(char *buffer, struct kernel_param *unused)
+fletcher_4_param_get(char *buffer, zfs_kernel_param_t *unused)
 {
 	const uint32_t impl = IMPL_READ(fletcher_4_impl_chosen);
 	char *fmt;
@@ -676,7 +677,7 @@ fletcher_4_param_get(char *buffer, struct kernel_param *unused)
 }
 
 static int
-fletcher_4_param_set(const char *val, struct kernel_param *unused)
+fletcher_4_param_set(const char *val, zfs_kernel_param_t *unused)
 {
 	return (fletcher_4_impl_set(val));
 }

module/zfs/vdev_raidz_math.c

@@ -120,7 +120,6 @@ vdev_raidz_math_get_ops()
 		ops = (raidz_impl_ops_t *) &vdev_raidz_scalar_impl;
 		break;
 	default:
-		ASSERT(raidz_math_initialized);
 		ASSERT3U(impl, <, raidz_supp_impl_cnt);
 		ASSERT3U(raidz_supp_impl_cnt, >, 0);
 		ops = raidz_supp_impl[impl];
@@ -556,8 +555,8 @@ static const struct {
  * @val		Name of raidz implementation to use
  * @param	Unused.
  */
-static int
+int
-zfs_vdev_raidz_impl_set(const char *val, struct kernel_param *kp)
+vdev_raidz_impl_set(const char *val)
 {
 	int err = -EINVAL;
 	char req_name[RAIDZ_IMPL_NAME_MAX];
@@ -605,17 +604,17 @@ zfs_vdev_raidz_impl_set(const char *val, struct kernel_param *kp)
 	return (err);
 }
 
-int
+#if defined(_KERNEL) && defined(HAVE_SPL)
-vdev_raidz_impl_set(const char *val)
+#include <linux/mod_compat.h>
-{
-	ASSERT(raidz_math_initialized);
 
-	return (zfs_vdev_raidz_impl_set(val, NULL));
+static int
+zfs_vdev_raidz_impl_set(const char *val, zfs_kernel_param_t *kp)
+{
+	return (vdev_raidz_impl_set(val));
 }
 
-#if defined(_KERNEL) && defined(HAVE_SPL)
 static int
-zfs_vdev_raidz_impl_get(char *buffer, struct kernel_param *kp)
+zfs_vdev_raidz_impl_get(char *buffer, zfs_kernel_param_t *kp)
 {
 	int i, cnt = 0;
 	char *fmt;