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Commit 730b69d2 authored by Rusty Russell's avatar Rusty Russell
Browse files

module: check kernel param length at compile time, not runtime 



The kparam code tries to handle over-length parameter prefixes at
runtime.  Not only would I bet this has never been tested, it's not
clear that truncating names is a good idea either.

So let's check at compile time.  We need to move the #define to
moduleparam.h to do this, though.

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent d72b3751

include/linux/module.h

+1 −1
Original line number Diff line number Diff line
@@ -29,7 +29,7 @@ 
#define MODULE_SYMBOL_PREFIX ""

#endif



#define MODULE_NAME_LEN (64 - sizeof(unsigned long))

#define MODULE_NAME_LEN MAX_PARAM_PREFIX_LEN



struct kernel_symbol

{

include/linux/moduleparam.h

+5 −1
Original line number Diff line number Diff line
@@ -13,6 +13,9 @@ 
#define MODULE_PARAM_PREFIX KBUILD_MODNAME "."

#endif



/* Chosen so that structs with an unsigned long line up. */

#define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long))



#ifdef MODULE

#define ___module_cat(a,b) __mod_ ## a ## b

#define __module_cat(a,b) ___module_cat(a,b)
@@ -79,7 +82,8 @@ struct kparam_array 
#define __module_param_call(prefix, name, set, get, arg, perm)		\

	/* Default value instead of permissions? */			\

	static int __param_perm_check_##name __attribute__((unused)) =	\

	BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2));	\

	BUILD_BUG_ON_ZERO((perm) < 0 || (perm) > 0777 || ((perm) & 2))	\

	+ BUILD_BUG_ON_ZERO(sizeof(""prefix) > MAX_PARAM_PREFIX_LEN);	\

	static const char __param_str_##name[] = prefix #name;		\

	static struct kernel_param __moduleparam_const __param_##name	\

	__used								\

kernel/params.c

+2 −5
Original line number Diff line number Diff line
@@ -585,17 +585,14 @@ static void __init param_sysfs_builtin(void) 
{

	struct kernel_param *kp, *kp_begin = NULL;

	unsigned int i, name_len, count = 0;

	char modname[MODULE_NAME_LEN + 1] = "";

	char modname[MODULE_NAME_LEN] = "";



	for (i=0; i < __stop___param - __start___param; i++) {

		char *dot;

		size_t max_name_len;



		kp = &__start___param[i];

		max_name_len =

			min_t(size_t, MODULE_NAME_LEN, strlen(kp->name));



		dot = memchr(kp->name, '.', max_name_len);

		dot = strchr(kp->name, '.');

		if (!dot) {

			DEBUGP("couldn't find period in first %d characters "

			       "of %s\n", MODULE_NAME_LEN, kp->name);