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/*
* Copyright 2016 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include "futility.h"
enum {
OPT_HELP = 1000,
OPT_OFFSET,
};
static const struct option long_opts[] = {
{"help", 0, 0, OPT_HELP},
{"offset", 1, 0, OPT_OFFSET},
{NULL, 0, NULL, 0},
};
static void print_help(int argc, char *argv[])
{
printf("\nUsage: " MYNAME " %s FILE [OPTIONS]\n", argv[0]);
printf("\nOptions:\n");
printf(" --offset <offset> Offset of cache within FILE\n");
printf("\n");
}
struct mrc_cache {
uint32_t signature;
uint32_t size;
uint32_t checksum;
uint32_t version;
uint8_t data[0];
} __attribute__((packed));
#define MRC_DATA_SIGNATURE (('M'<<0)|('R'<<8)|('C'<<16)|('D'<<24))
unsigned long compute_ip_checksum(void *addr, unsigned long length)
{
uint8_t *ptr;
volatile union {
uint8_t byte[2];
uint16_t word;
} value;
unsigned long sum;
unsigned long i;
/* In the most straight forward way possible,
* compute an ip style checksum.
*/
sum = 0;
ptr = addr;
for(i = 0; i < length; i++) {
unsigned long v;
v = ptr[i];
if (i & 1) {
v <<= 8;
}
/* Add the new value */
sum += v;
/* Wrap around the carry */
if (sum > 0xFFFF) {
sum = (sum + (sum >> 16)) & 0xFFFF;
}
}
value.byte[0] = sum & 0xff;
value.byte[1] = (sum >> 8) & 0xff;
return (~value.word) & 0xFFFF;
}
static int verify_checksum(struct mrc_cache *cache, unsigned long cache_len)
{
uint32_t checksum;
if (cache->signature != MRC_DATA_SIGNATURE) {
fprintf(stderr, "MRC signature mismatch\n");
return 1;
}
fprintf(stderr, "MRC signature match.. successful\n");
if (cache->size > cache_len) {
fprintf(stderr, "MRC cache size overflow\n");
return 1;
}
checksum = compute_ip_checksum((void *)&cache->data[0], cache->size);
if (checksum != cache->checksum) {
fprintf(stderr, "MRC checksum mismatch\n");
return 1;
}
fprintf(stderr, "MRC checksum.. verified!\n");
return 0;
}
static int do_validate_rec_mrc(int argc, char *argv[])
{
char *infile = NULL;
int parse_error = 0;
int fd, i, ret = 1;
uint32_t file_size;
uint8_t *buff;
uint32_t offset = 0;
char *e;
while (((i = getopt_long(argc, argv, ":", long_opts, NULL)) != -1) &&
!parse_error) {
switch (i) {
case OPT_HELP:
print_help(argc, argv);
return 0;
case OPT_OFFSET:
offset = strtoul(optarg, &e, 0);
if (!*optarg || (e && *e)) {
fprintf(stderr, "Invalid --offset\n");
parse_error = 1;
}
break;
default:
case '?':
parse_error = 1;
break;
}
}
if (parse_error) {
print_help(argc, argv);
return 1;
}
if ((argc - optind) < 1) {
fprintf(stderr, "You must specify an input FILE!\n");
print_help(argc, argv);
return 1;
} else if ((argc - optind) != 1) {
fprintf(stderr, "Unexpected arguments!\n");
print_help(argc, argv);
return 1;
}
infile = argv[optind++];
fd = open(infile, O_RDONLY);
if (fd < 0) {
fprintf(stderr, "Cannot open %s:%s\n", infile, strerror(errno));
return 1;
}
if (futil_map_file(fd, MAP_RO, &buff, &file_size) != FILE_ERR_NONE) {
fprintf(stderr, "Cannot map file %s\n", infile);
close(fd);
return 1;
}
if (file_size > offset)
ret = verify_checksum((struct mrc_cache *)(buff + offset),
file_size - offset);
else
fprintf(stderr, "Offset greater than file size: offset=0x%x, "
"file size=0x%x\n", offset, file_size);
if (futil_unmap_file(fd, MAP_RO, buff, file_size) != FILE_ERR_NONE) {
fprintf(stderr, "Failed to unmap file %s\n", infile);
ret = 1;
}
close(fd);
return ret;
}
DECLARE_FUTIL_COMMAND(validate_rec_mrc, do_validate_rec_mrc, VBOOT_VERSION_ALL,
"Validates content of Recovery MRC cache");
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