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Commit 7a486d37 authored by Rusty Russell's avatar Rusty Russell
Browse files

param: check for tainting before calling set op. 



This means every set op doesn't need to call it, and it can move into
params.c.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent fc9740ce

include/linux/moduleparam.h

+0 −16
Original line number Diff line number Diff line
@@ -374,22 +374,6 @@ static inline void destroy_params(const struct kernel_param *params, 
#define __param_check(name, p, type) \

	static inline type __always_unused *__check_##name(void) { return(p); }



/**

 * param_check_unsafe - Warn and taint the kernel if setting dangerous options.

 *

 * This gets called from all the standard param setters, but can be used from

 * custom setters as well.

 */

static inline void

param_check_unsafe(const struct kernel_param *kp)

{

	if (kp->flags & KERNEL_PARAM_FL_UNSAFE) {

		pr_warn("Setting dangerous option %s - tainting kernel\n",

			kp->name);

		add_taint(TAINT_USER, LOCKDEP_STILL_OK);

	}

}



extern struct kernel_param_ops param_ops_byte;

extern int param_set_byte(const char *val, const struct kernel_param *kp);

extern int param_get_byte(char *buffer, const struct kernel_param *kp);

kernel/params.c

+11 −11
Original line number Diff line number Diff line
@@ -83,6 +83,15 @@ bool parameq(const char *a, const char *b) 
	return parameqn(a, b, strlen(a)+1);

}



static void param_check_unsafe(const struct kernel_param *kp)

{

	if (kp->flags & KERNEL_PARAM_FL_UNSAFE) {

		pr_warn("Setting dangerous option %s - tainting kernel\n",

			kp->name);

		add_taint(TAINT_USER, LOCKDEP_STILL_OK);

	}

}



static int parse_one(char *param,

		     char *val,

		     const char *doing,
@@ -109,6 +118,7 @@ static int parse_one(char *param, 
			pr_debug("handling %s with %p\n", param,

				params[i].ops->set);

			mutex_lock(&param_lock);

			param_check_unsafe(&params[i]);

			err = params[i].ops->set(val, &params[i]);

			mutex_unlock(&param_lock);

			return err;
@@ -233,7 +243,6 @@ 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) \
@@ -266,8 +275,6 @@ 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
@@ -305,8 +312,6 @@ 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";
@@ -336,8 +341,6 @@ 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)
@@ -364,8 +367,6 @@ 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;
@@ -485,8 +486,6 @@ 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);
@@ -563,6 +562,7 @@ static ssize_t param_attr_store(struct module_attribute *mattr, 
		return -EPERM;



	mutex_lock(&param_lock);

	param_check_unsafe(attribute->param);

	err = attribute->param->ops->set(buf, attribute->param);

	mutex_unlock(&param_lock);

	if (!err)