1 files changed, 182 insertions, 0 deletions
diff --git a/futility/cmd_validate_rec_mrc.c b/futility/cmd_validate_rec_mrc.c
new file mode 100644
index 00000000..3013891a
--- /dev/null
+++ b/futility/cmd_validate_rec_mrc.c
@@ -0,0 +1,182 @@
+/*
+ * 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");