From 91f9d330cc14932084c37751997213cb0e7ea882 Mon Sep 17 00:00:00 2001
From: Jani Nikula <jani.nikula@intel.com>
Date: Wed, 27 Aug 2014 06:22:23 +0930
Subject: module: make it possible to have unsafe, tainting module params

Add flags field to struct kernel_params, and add the first flag: unsafe
parameter. Modifying a kernel parameter with the unsafe flag set, either
via the kernel command line or sysfs, will issue a warning and taint the
kernel.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Jon Mason <jon.mason@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 kernel/params.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

(limited to 'kernel/params.c')

diff --git a/kernel/params.c b/kernel/params.c
index 8a484fc8bde8..ad8d04563c3a 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -233,6 +233,7 @@ char *parse_args(const char *doing,
 #define STANDARD_PARAM_DEF(name, type, format, strtolfn)      		\
 	int param_set_##name(const char *val, const struct kernel_param *kp) \
 	{								\
+		param_check_unsafe(kp);					\
 		return strtolfn(val, 0, (type *)kp->arg);		\
 	}								\
 	int param_get_##name(char *buffer, const struct kernel_param *kp) \
@@ -265,6 +266,8 @@ int param_set_charp(const char *val, const struct kernel_param *kp)
 		return -ENOSPC;
 	}
 
+	param_check_unsafe(kp);
+
 	maybe_kfree_parameter(*(char **)kp->arg);
 
 	/* This is a hack.  We can't kmalloc in early boot, and we
@@ -302,6 +305,8 @@ EXPORT_SYMBOL(param_ops_charp);
 /* Actually could be a bool or an int, for historical reasons. */
 int param_set_bool(const char *val, const struct kernel_param *kp)
 {
+	param_check_unsafe(kp);
+
 	/* No equals means "set"... */
 	if (!val) val = "1";
 
@@ -331,6 +336,8 @@ int param_set_invbool(const char *val, const struct kernel_param *kp)
 	bool boolval;
 	struct kernel_param dummy;
 
+	param_check_unsafe(kp);
+
 	dummy.arg = &boolval;
 	ret = param_set_bool(val, &dummy);
 	if (ret == 0)
@@ -357,6 +364,8 @@ int param_set_bint(const char *val, const struct kernel_param *kp)
 	bool v;
 	int ret;
 
+	param_check_unsafe(kp);
+
 	/* Match bool exactly, by re-using it. */
 	boolkp = *kp;
 	boolkp.arg = &v;
@@ -476,6 +485,8 @@ int param_set_copystring(const char *val, const struct kernel_param *kp)
 {
 	const struct kparam_string *kps = kp->str;
 
+	param_check_unsafe(kp);
+
 	if (strlen(val)+1 > kps->maxlen) {
 		pr_err("%s: string doesn't fit in %u chars.\n",
 		       kp->name, kps->maxlen-1);
-- 
cgit