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Commit 2e9fb995 authored by Rusty Russell's avatar Rusty Russell
Browse files

params: don't hand NULL values to param.set callbacks. 



An audit by Dongdong Deng revealed that most driver-author-written param
calls don't handle val == NULL (which happens when parameters are specified
with no =, eg "foo" instead of "foo=1").

The only real case to use this is boolean, so handle it specially for that
case and remove a source of bugs for everyone else.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Cc: Dongdong Deng <dongdong.deng@windriver.com>
Cc: Américo Wang <xiyou.wangcong@gmail.com>
parent d2800800

kernel/params.c

+3 −17
Original line number Diff line number Diff line
@@ -58,6 +58,9 @@ static int parse_one(char *param, 
	/* Find parameter */

	for (i = 0; i < num_params; i++) {

		if (parameq(param, params[i].name)) {

			/* Noone handled NULL, so do it here. */

			if (!val && params[i].set != param_set_bool)

				return -EINVAL;

			DEBUGP("They are equal!  Calling %p\n",

			       params[i].set);

			return params[i].set(val, &params[i]);
@@ -181,7 +184,6 @@ int parse_args(const char *name, 
		tmptype l;						\

		int ret;						\

									\

		if (!val) return -EINVAL;				\

		ret = strtolfn(val, 0, &l);				\

		if (ret == -EINVAL || ((type)l != l))			\

			return -EINVAL;					\
@@ -203,12 +205,6 @@ STANDARD_PARAM_DEF(ulong, unsigned long, "%lu", unsigned long, strict_strtoul); 


int param_set_charp(const char *val, struct kernel_param *kp)

{

	if (!val) {

		printk(KERN_ERR "%s: string parameter expected\n",

		       kp->name);

		return -EINVAL;

	}



	if (strlen(val) > 1024) {

		printk(KERN_ERR "%s: string parameter too long\n",

		       kp->name);
@@ -309,12 +305,6 @@ static int param_array(const char *name, 
	kp.arg = elem;

	kp.flags = flags;



	/* No equals sign? */

	if (!val) {

		printk(KERN_ERR "%s: expects arguments\n", name);

		return -EINVAL;

	}



	*num = 0;

	/* We expect a comma-separated list of values. */

	do {
@@ -381,10 +371,6 @@ int param_set_copystring(const char *val, struct kernel_param *kp) 
{

	const struct kparam_string *kps = kp->str;



	if (!val) {

		printk(KERN_ERR "%s: missing param set value\n", kp->name);

		return -EINVAL;

	}

	if (strlen(val)+1 > kps->maxlen) {

		printk(KERN_ERR "%s: string doesn't fit in %u chars.\n",

		       kp->name, kps->maxlen-1);