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- /*
- * Copyright (C) 2015 Thomas Hebb <tommyhebb@gmail.com>
- *
- * The format of the header this tool generates was first documented by
- * Chris Blake <chrisrblake93 (at) gmail.com> in a shell script of the
- * same purpose. I have created this reimplementation at his request. The
- * original script can be found at:
- * <https://github.com/riptidewave93/meraki-partbuilder>
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published
- * by the Free Software Foundation.
- *
- */
- #include <stdio.h>
- #include <stdlib.h>
- #include <stdbool.h>
- #include <string.h>
- #include <libgen.h>
- #include <getopt.h>
- #include <errno.h>
- #include <arpa/inet.h>
- #include "sha1.h"
- #define PADDING_BYTE 0xff
- #define HDR_LENGTH 0x00000400
- #define HDR_OFF_MAGIC1 0
- #define HDR_OFF_HDRLEN 4
- #define HDR_OFF_IMAGELEN 8
- #define HDR_OFF_CHECKSUM 12
- #define HDR_OFF_MAGIC2 32
- #define HDR_OFF_MAGIC3 36
- #define HDR_OFF_STATICHASH 40
- #define HDR_OFF_KERNEL_OFFSET 40
- #define HDR_OFF_RAMDISK_OFFSET 44
- #define HDR_OFF_FDT_OFFSET 48
- #define HDR_OFF_UNKNOWN_OFFSET 52
- struct board_info {
- uint32_t magic1;
- uint32_t magic2;
- uint32_t magic3;
- uint32_t imagelen;
- union {
- unsigned char statichash[20];
- struct {
- uint32_t kernel_offset;
- uint32_t ramdisk_offset;
- uint32_t fdt_offset;
- uint32_t unknown_offset;
- } mx60;
- } u;
- char *id;
- char *description;
- };
- /*
- * Globals
- */
- static char *progname;
- static char *board_id;
- static const struct board_info *board;
- static const struct board_info boards[] = {
- {
- .id = "mr18",
- .description = "Meraki MR18 Access Point",
- .magic1 = 0x8e73ed8a,
- .magic2 = 0x8e73ed8a,
- .imagelen = 0x00800000,
- .u.statichash = {0xda, 0x39, 0xa3, 0xee, 0x5e,
- 0x6b, 0x4b, 0x0d, 0x32, 0x55,
- 0xbf, 0xef, 0x95, 0x60, 0x18,
- 0x90, 0xaf, 0xd8, 0x07, 0x09},
- }, {
- .id = "mr24",
- .description = "Meraki MR24 Access Point",
- .magic1 = 0x8e73ed8a,
- .magic2 = 0x8e73ed8a,
- .imagelen = 0x00800000,
- .u.statichash = {0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff},
- }, {
- .id = "mx60",
- .description = "Meraki MX60/MX60W Security Appliance",
- .magic1 = 0x8e73ed8a,
- .magic2 = 0xa1f0beef, /* Enables use of load addr in statichash */
- .magic3 = 0x00060001, /* This goes along with magic2 */
- .imagelen = 0x3fd00000,
- /* The static hash below does the following:
- * 1st Row: Kernel Offset
- * 2nd Row: Ramdisk Offset
- * 3rd Row: FDT Offset
- * 4th Row: ? Unused/Unknown ?
- * 5th Row: ? Unused/Unknown ?
- */
- .u.mx60 = {
- .kernel_offset = 0x10000,
- .ramdisk_offset = 0x3FFC00,
- .fdt_offset = 0x0400,
- .unknown_offset = 0x0400,
- },
- }, {
- /* terminating entry */
- }
- };
- /*
- * Message macros
- */
- #define ERR(fmt, ...) do { \
- fflush(0); \
- fprintf(stderr, "[%s] *** error: " fmt "\n", \
- progname, ## __VA_ARGS__); \
- } while (0)
- #define ERRS(fmt, ...) do { \
- int save = errno; \
- fflush(0); \
- fprintf(stderr, "[%s] *** error: " fmt "\n", \
- progname, ## __VA_ARGS__, strerror(save)); \
- } while (0)
- static const struct board_info *find_board(const char *id)
- {
- const struct board_info *ret;
- const struct board_info *board;
- ret = NULL;
- for (board = boards; board->id != NULL; board++) {
- if (strcasecmp(id, board->id) == 0) {
- ret = board;
- break;
- }
- }
- return ret;
- }
- static void usage(int status)
- {
- FILE *stream = (status != EXIT_SUCCESS) ? stderr : stdout;
- const struct board_info *board;
- fprintf(stream, "Usage: %s [OPTIONS...]\n", progname);
- fprintf(stream,
- "\n"
- "Options:\n"
- " -B <board> create image for the board specified with <board>\n"
- " -i <file> read kernel image from the file <file>\n"
- " -o <file> write output to the file <file>\n"
- " -s strip padding from the end of the image\n"
- " -h show this screen\n"
- );
- fprintf(stream, "\nBoards:\n");
- for (board = boards; board->id != NULL; board++)
- fprintf(stream, " %-16s%s\n", board->id, board->description);
- exit(status);
- }
- void writel(unsigned char *buf, size_t offset, uint32_t value)
- {
- value = htonl(value);
- memcpy(buf + offset, &value, sizeof(uint32_t));
- }
- int main(int argc, char *argv[])
- {
- int ret = EXIT_FAILURE;
- long klen;
- size_t kspace;
- unsigned char *kernel;
- size_t buflen;
- unsigned char *buf;
- bool strip_padding = false;
- char *ofname = NULL, *ifname = NULL;
- FILE *out, *in;
- progname = basename(argv[0]);
- while (1) {
- int c;
- c = getopt(argc, argv, "B:i:o:sh");
- if (c == -1)
- break;
- switch (c) {
- case 'B':
- board_id = optarg;
- break;
- case 'i':
- ifname = optarg;
- break;
- case 'o':
- ofname = optarg;
- break;
- case 's':
- strip_padding = true;
- break;
- case 'h':
- usage(EXIT_SUCCESS);
- break;
- default:
- usage(EXIT_FAILURE);
- break;
- }
- }
- if (board_id == NULL) {
- ERR("no board specified");
- goto err;
- }
- board = find_board(board_id);
- if (board == NULL) {
- ERR("unknown board \"%s\"", board_id);
- goto err;
- }
- if (ifname == NULL) {
- ERR("no input file specified");
- goto err;
- }
- if (ofname == NULL) {
- ERR("no output file specified");
- goto err;
- }
- in = fopen(ifname, "r");
- if (in == NULL) {
- ERRS("could not open \"%s\" for reading: %s", ifname);
- goto err;
- }
- buflen = board->imagelen;
- kspace = buflen - HDR_LENGTH;
- /* Get kernel length */
- fseek(in, 0, SEEK_END);
- klen = ftell(in);
- rewind(in);
- if (klen > kspace) {
- ERR("file \"%s\" is too big - max size: 0x%08lX\n",
- ifname, kspace);
- goto err_close_in;
- }
- /* If requested, resize buffer to remove padding */
- if (strip_padding)
- buflen = klen + HDR_LENGTH;
- /* Allocate and initialize buffer for final image */
- buf = malloc(buflen);
- if (buf == NULL) {
- ERRS("no memory for buffer: %s\n");
- goto err_close_in;
- }
- memset(buf, PADDING_BYTE, buflen);
- /* Load kernel */
- kernel = buf + HDR_LENGTH;
- fread(kernel, klen, 1, in);
- /* Write magic values */
- writel(buf, HDR_OFF_MAGIC1, board->magic1);
- writel(buf, HDR_OFF_MAGIC2, board->magic2);
- writel(buf, HDR_OFF_MAGIC3, board->magic3);
- /* Write header and image length */
- writel(buf, HDR_OFF_HDRLEN, HDR_LENGTH);
- writel(buf, HDR_OFF_IMAGELEN, klen);
- /* Write checksum and static hash */
- sha1_csum(kernel, klen, buf + HDR_OFF_CHECKSUM);
- switch (board->magic2) {
- case 0xa1f0beef:
- writel(buf, HDR_OFF_KERNEL_OFFSET, board->u.mx60.kernel_offset);
- writel(buf, HDR_OFF_RAMDISK_OFFSET, board->u.mx60.ramdisk_offset);
- writel(buf, HDR_OFF_FDT_OFFSET, board->u.mx60.fdt_offset),
- writel(buf, HDR_OFF_UNKNOWN_OFFSET, board->u.mx60.unknown_offset);
- break;
- case 0x8e73ed8a:
- memcpy(buf + HDR_OFF_STATICHASH, board->u.statichash, 20);
- break;
- }
- /* Save finished image */
- out = fopen(ofname, "w");
- if (out == NULL) {
- ERRS("could not open \"%s\" for writing: %s", ofname);
- goto err_free;
- }
- fwrite(buf, buflen, 1, out);
- ret = EXIT_SUCCESS;
- fclose(out);
- err_free:
- free(buf);
- err_close_in:
- fclose(in);
- err:
- return ret;
- }
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