swh:1:snp:77163734605b0ec556b01d897b7bb4a7e30d46b6
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Tip revision: 3123109284176b1532874591f7c81f3837bbdc17 authored by Linus Torvalds on 03 April 2022, 21:08:21 UTC
Linux 5.18-rc1
Tip revision: 3123109
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_err("FAIL: survived mismatched prototype function call!\n");
	pr_expected_config(CONFIG_CFI_CLANG);
}
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