[mirror_ubuntu-hirsute-kernel.git] / drivers / misc / lkdtm / cfi.c

// SPDX-License-Identifier: GPL-2.0
/*
 * This is for all the tests relating directly to Control Flow Integrity.
 */
#include "lkdtm.h"

static int called_count;

/* Function taking one argument, without a return value. */
static noinline void lkdtm_increment_void(int *counter)
{
	(*counter)++;
}

/* Function taking one argument, returning int. */
static noinline int lkdtm_increment_int(int *counter)
{
	(*counter)++;

	return *counter;
}
/*
 * This tries to call an indirect function with a mismatched prototype.
 */
void lkdtm_CFI_FORWARD_PROTO(void)
{
	/*
	 * Matches lkdtm_increment_void()'s prototype, but not
	 * lkdtm_increment_int()'s prototype.
	 */
	void (*func)(int *);

	pr_info("Calling matched prototype ...\n");
	func = lkdtm_increment_void;
	func(&called_count);

	pr_info("Calling mismatched prototype ...\n");
	func = (void *)lkdtm_increment_int;
	func(&called_count);

	pr_info("Fail: survived mismatched prototype function call!\n");
}
Commit	Line	Data
b0eb93cf KC	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* This is for all the tests relating directly to Control Flow Integrity.
	4	*/
	5	#include "lkdtm.h"
	6
	7	static int called_count;
	8
	9	/* Function taking one argument, without a return value. */
	10	static noinline void lkdtm_increment_void(int *counter)
	11	{
	12	(*counter)++;
	13	}
	14
	15	/* Function taking one argument, returning int. */
	16	static noinline int lkdtm_increment_int(int *counter)
	17	{
	18	(*counter)++;
	19
	20	return *counter;
	21	}
	22	/*
	23	* This tries to call an indirect function with a mismatched prototype.
	24	*/
	25	void lkdtm_CFI_FORWARD_PROTO(void)
	26	{
	27	/*
	28	* Matches lkdtm_increment_void()'s prototype, but not
	29	* lkdtm_increment_int()'s prototype.
	30	*/
	31	void (func)(int );
	32
	33	pr_info("Calling matched prototype ...\n");
	34	func = lkdtm_increment_void;
	35	func(&called_count);
	36
	37	pr_info("Calling mismatched prototype ...\n");
	38	func = (void *)lkdtm_increment_int;
	39	func(&called_count);
	40
	41	pr_info("Fail: survived mismatched prototype function call!\n");
	42	}