cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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memcmp.c (3818B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include <malloc.h>
      3#include <stdlib.h>
      4#include <string.h>
      5#include <sys/mman.h>
      6#include <time.h>
      7
      8#include "utils.h"
      9
     10#define SIZE 256
     11#define ITERATIONS 10000
     12
     13#define LARGE_SIZE (5 * 1024)
     14#define LARGE_ITERATIONS 1000
     15#define LARGE_MAX_OFFSET 32
     16#define LARGE_SIZE_START 4096
     17
     18/* This is big enough to fit LARGE_SIZE and works on 4K & 64K kernels */
     19#define MAP_SIZE (64 * 1024)
     20
     21#define MAX_OFFSET_DIFF_S1_S2 48
     22
     23int vmx_count;
     24int enter_vmx_ops(void)
     25{
     26	vmx_count++;
     27	return 1;
     28}
     29
     30void exit_vmx_ops(void)
     31{
     32	vmx_count--;
     33}
     34int test_memcmp(const void *s1, const void *s2, size_t n);
     35
     36/* test all offsets and lengths */
     37static void test_one(char *s1, char *s2, unsigned long max_offset,
     38		unsigned long size_start, unsigned long max_size)
     39{
     40	unsigned long offset, size;
     41
     42	for (offset = 0; offset < max_offset; offset++) {
     43		for (size = size_start; size < (max_size - offset); size++) {
     44			int x, y;
     45			unsigned long i;
     46
     47			y = memcmp(s1+offset, s2+offset, size);
     48			x = test_memcmp(s1+offset, s2+offset, size);
     49
     50			if (((x ^ y) < 0) &&	/* Trick to compare sign */
     51				((x | y) != 0)) { /* check for zero */
     52				printf("memcmp returned %d, should have returned %d (offset %ld size %ld)\n", x, y, offset, size);
     53
     54				for (i = offset; i < offset+size; i++)
     55					printf("%02x ", s1[i]);
     56				printf("\n");
     57
     58				for (i = offset; i < offset+size; i++)
     59					printf("%02x ", s2[i]);
     60				printf("\n");
     61				abort();
     62			}
     63
     64			if (vmx_count != 0) {
     65				printf("vmx enter/exit not paired.(offset:%ld size:%ld s1:%p s2:%p vc:%d\n",
     66					offset, size, s1, s2, vmx_count);
     67				printf("\n");
     68				abort();
     69			}
     70		}
     71	}
     72}
     73
     74static int testcase(bool islarge)
     75{
     76	unsigned long i, comp_size, alloc_size;
     77	char *p, *s1, *s2;
     78	int iterations;
     79
     80	comp_size = (islarge ? LARGE_SIZE : SIZE);
     81	alloc_size = comp_size + MAX_OFFSET_DIFF_S1_S2;
     82	iterations = islarge ? LARGE_ITERATIONS : ITERATIONS;
     83
     84	p = mmap(NULL, 4 * MAP_SIZE, PROT_READ | PROT_WRITE,
     85		 MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
     86	FAIL_IF(p == MAP_FAILED);
     87
     88	/* Put s1/s2 at the end of a page */
     89	s1 = p + MAP_SIZE - alloc_size;
     90	s2 = p + 3 * MAP_SIZE - alloc_size;
     91
     92	/* And unmap the subsequent page to force a fault if we overread */
     93	munmap(p + MAP_SIZE, MAP_SIZE);
     94	munmap(p + 3 * MAP_SIZE, MAP_SIZE);
     95
     96	srandom(time(0));
     97
     98	for (i = 0; i < iterations; i++) {
     99		unsigned long j;
    100		unsigned long change;
    101		char *rand_s1 = s1;
    102		char *rand_s2 = s2;
    103
    104		for (j = 0; j < alloc_size; j++)
    105			s1[j] = random();
    106
    107		rand_s1 += random() % MAX_OFFSET_DIFF_S1_S2;
    108		rand_s2 += random() % MAX_OFFSET_DIFF_S1_S2;
    109		memcpy(rand_s2, rand_s1, comp_size);
    110
    111		/* change one byte */
    112		change = random() % comp_size;
    113		rand_s2[change] = random() & 0xff;
    114
    115		if (islarge)
    116			test_one(rand_s1, rand_s2, LARGE_MAX_OFFSET,
    117					LARGE_SIZE_START, comp_size);
    118		else
    119			test_one(rand_s1, rand_s2, SIZE, 0, comp_size);
    120	}
    121
    122	srandom(time(0));
    123
    124	for (i = 0; i < iterations; i++) {
    125		unsigned long j;
    126		unsigned long change;
    127		char *rand_s1 = s1;
    128		char *rand_s2 = s2;
    129
    130		for (j = 0; j < alloc_size; j++)
    131			s1[j] = random();
    132
    133		rand_s1 += random() % MAX_OFFSET_DIFF_S1_S2;
    134		rand_s2 += random() % MAX_OFFSET_DIFF_S1_S2;
    135		memcpy(rand_s2, rand_s1, comp_size);
    136
    137		/* change multiple bytes, 1/8 of total */
    138		for (j = 0; j < comp_size / 8; j++) {
    139			change = random() % comp_size;
    140			s2[change] = random() & 0xff;
    141		}
    142
    143		if (islarge)
    144			test_one(rand_s1, rand_s2, LARGE_MAX_OFFSET,
    145					LARGE_SIZE_START, comp_size);
    146		else
    147			test_one(rand_s1, rand_s2, SIZE, 0, comp_size);
    148	}
    149
    150	return 0;
    151}
    152
    153static int testcases(void)
    154{
    155#ifdef __powerpc64__
    156	// vcmpequd used in memcmp_64.S is v2.07
    157	SKIP_IF(!have_hwcap2(PPC_FEATURE2_ARCH_2_07));
    158#endif
    159
    160	testcase(0);
    161	testcase(1);
    162	return 0;
    163}
    164
    165int main(void)
    166{
    167	test_harness_set_timeout(300);
    168	return test_harness(testcases, "memcmp");
    169}