tools/firmware-utils/src/mkmerakifw.c

   1 /*
   2  * Copyright (C) 2015 Thomas Hebb <tommyhebb@gmail.com>
   3  *
   4  * The format of the header this tool generates was first documented by
   5  * Chris Blake <chrisrblake93 (at) gmail.com> in a shell script of the
   6  * same purpose. I have created this reimplementation at his request. The
   7  * original script can be found at:
   8  * <https://github.com/riptidewave93/meraki-partbuilder>
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU General Public License version 2 as published
  12  * by the Free Software Foundation.
  13  *
  14  */
  15
  16 #include <stdio.h>
  17 #include <stdlib.h>
  18 #include <stdbool.h>
  19 #include <string.h>
  20 #include <libgen.h>
  21 #include <getopt.h>
  22 #include <errno.h>
  23 #include <arpa/inet.h>
  24
  25 #include "sha1.h"
  26
  27 #define PADDING_BYTE            0xff
  28
  29 #define HDR_LENGTH              0x00000400
  30 #define HDR_OFF_MAGIC1          0
  31 #define HDR_OFF_HDRLEN          4
  32 #define HDR_OFF_IMAGELEN        8
  33 #define HDR_OFF_CHECKSUM        12
  34 #define HDR_OFF_MAGIC2          32
  35 #define HDR_OFF_MAGIC3          36
  36 #define HDR_OFF_STATICHASH      40
  37 #define HDR_OFF_KERNEL_OFFSET   40
  38 #define HDR_OFF_RAMDISK_OFFSET  44
  39 #define HDR_OFF_FDT_OFFSET      48
  40 #define HDR_OFF_UNKNOWN_OFFSET  52
  41
  42 struct board_info {
  43         uint32_t magic1;
  44         uint32_t magic2;
  45         uint32_t magic3;
  46         uint32_t imagelen;
  47         union {
  48                 unsigned char statichash[20];
  49                 struct {
  50                         uint32_t kernel_offset;
  51                         uint32_t ramdisk_offset;
  52                         uint32_t fdt_offset;
  53                         uint32_t unknown_offset;
  54                 } mx60;
  55         } u;
  56         char *id;
  57         char *description;
  58 };
  59
  60 /*
  61  * Globals
  62  */
  63 static char *progname;
  64
  65 static char *board_id;
  66 static const struct board_info *board;
  67
  68 static const struct board_info boards[] = {
  69         {
  70                 .id             = "mr18",
  71                 .description    = "Meraki MR18 Access Point",
  72                 .magic1         = 0x8e73ed8a,
  73                 .magic2         = 0x8e73ed8a,
  74                 .imagelen       = 0x00800000,
  75                 .u.statichash   = {0xda, 0x39, 0xa3, 0xee, 0x5e,
  76                                    0x6b, 0x4b, 0x0d, 0x32, 0x55,
  77                                    0xbf, 0xef, 0x95, 0x60, 0x18,
  78                                    0x90, 0xaf, 0xd8, 0x07, 0x09},
  79         }, {
  80                 .id             = "mr24",
  81                 .description    = "Meraki MR24 Access Point",
  82                 .magic1         = 0x8e73ed8a,
  83                 .magic2         = 0x8e73ed8a,
  84                 .imagelen       = 0x00800000,
  85                 .u.statichash   = {0xff, 0xff, 0xff, 0xff, 0xff,
  86                                    0xff, 0xff, 0xff, 0xff, 0xff,
  87                                    0xff, 0xff, 0xff, 0xff, 0xff,
  88                                    0xff, 0xff, 0xff, 0xff, 0xff},
  89         }, {
  90                 .id             = "mx60",
  91                 .description    = "Meraki MX60/MX60W Security Appliance",
  92                 .magic1         = 0x8e73ed8a,
  93                 .magic2         = 0xa1f0beef, /* Enables use of load addr in statichash */
  94                 .magic3         = 0x00060001, /* This goes along with magic2 */
  95                 .imagelen       = 0x3fd00000,
  96                 /* The static hash below does the following:
  97                  * 1st Row: Kernel Offset
  98                  * 2nd Row: Ramdisk Offset
  99                  * 3rd Row: FDT Offset
 100                  * 4th Row: ? Unused/Unknown ?
 101                  * 5th Row: ? Unused/Unknown ?
 102                  */
 103                 .u.mx60         = {
 104                         .kernel_offset  = 0x10000,
 105                         .ramdisk_offset = 0x3FFC00,
 106                         .fdt_offset     = 0x0400,
 107                         .unknown_offset = 0x0400,
 108                 },
 109         }, {
 110                 /* terminating entry */
 111         }
 112 };
 113
 114 /*
 115  * Message macros
 116  */
 117 #define ERR(fmt, ...) do { \
 118         fflush(0); \
 119         fprintf(stderr, "[%s] *** error: " fmt "\n", \
 120                         progname, ## __VA_ARGS__); \
 121 } while (0)
 122
 123 #define ERRS(fmt, ...) do { \
 124         int save = errno; \
 125         fflush(0); \
 126         fprintf(stderr, "[%s] *** error: " fmt "\n", \
 127                         progname, ## __VA_ARGS__, strerror(save)); \
 128 } while (0)
 129
 130 static const struct board_info *find_board(const char *id)
 131 {
 132         const struct board_info *ret;
 133         const struct board_info *board;
 134
 135         ret = NULL;
 136         for (board = boards; board->id != NULL; board++) {
 137                 if (strcasecmp(id, board->id) == 0) {
 138                         ret = board;
 139                         break;
 140                 }
 141         }
 142
 143         return ret;
 144 }
 145
 146 static void usage(int status)
 147 {
 148         FILE *stream = (status != EXIT_SUCCESS) ? stderr : stdout;
 149         const struct board_info *board;
 150
 151         fprintf(stream, "Usage: %s [OPTIONS...]\n", progname);
 152         fprintf(stream,
 153 "\n"
 154 "Options:\n"
 155 "  -B <board>      create image for the board specified with <board>\n"
 156 "  -i <file>       read kernel image from the file <file>\n"
 157 "  -o <file>       write output to the file <file>\n"
 158 "  -s              strip padding from the end of the image\n"
 159 "  -h              show this screen\n"
 160         );
 161
 162         fprintf(stream, "\nBoards:\n");
 163         for (board = boards; board->id != NULL; board++)
 164                 fprintf(stream, "  %-16s%s\n", board->id, board->description);
 165
 166         exit(status);
 167 }
 168
 169 void writel(unsigned char *buf, size_t offset, uint32_t value)
 170 {
 171         value = htonl(value);
 172         memcpy(buf + offset, &value, sizeof(uint32_t));
 173 }
 174
 175 int main(int argc, char *argv[])
 176 {
 177         int ret = EXIT_FAILURE;
 178         long klen;
 179         size_t kspace;
 180         unsigned char *kernel;
 181         size_t buflen;
 182         unsigned char *buf;
 183         bool strip_padding = false;
 184         char *ofname = NULL, *ifname = NULL;
 185         FILE *out, *in;
 186
 187         progname = basename(argv[0]);
 188
 189         while (1) {
 190                 int c;
 191
 192                 c = getopt(argc, argv, "B:i:o:sh");
 193                 if (c == -1)
 194                         break;
 195
 196                 switch (c) {
 197                 case 'B':
 198                         board_id = optarg;
 199                         break;
 200                 case 'i':
 201                         ifname = optarg;
 202                         break;
 203                 case 'o':
 204                         ofname = optarg;
 205                         break;
 206                 case 's':
 207                         strip_padding = true;
 208                         break;
 209                 case 'h':
 210                         usage(EXIT_SUCCESS);
 211                         break;
 212                 default:
 213                         usage(EXIT_FAILURE);
 214                         break;
 215                 }
 216         }
 217
 218         if (board_id == NULL) {
 219                 ERR("no board specified");
 220                 goto err;
 221         }
 222
 223         board = find_board(board_id);
 224         if (board == NULL) {
 225                 ERR("unknown board \"%s\"", board_id);
 226                 goto err;
 227         }
 228
 229         if (ifname == NULL) {
 230                 ERR("no input file specified");
 231                 goto err;
 232         }
 233
 234         if (ofname == NULL) {
 235                 ERR("no output file specified");
 236                 goto err;
 237         }
 238
 239         in = fopen(ifname, "r");
 240         if (in == NULL) {
 241                 ERRS("could not open \"%s\" for reading: %s", ifname);
 242                 goto err;
 243         }
 244
 245         buflen = board->imagelen;
 246         kspace = buflen - HDR_LENGTH;
 247
 248         /* Get kernel length */
 249         fseek(in, 0, SEEK_END);
 250         klen = ftell(in);
 251         rewind(in);
 252
 253         if (klen > kspace) {
 254                 ERR("file \"%s\" is too big - max size: 0x%08lX\n",
 255                     ifname, kspace);
 256                 goto err_close_in;
 257         }
 258
 259         /* If requested, resize buffer to remove padding */
 260         if (strip_padding)
 261                 buflen = klen + HDR_LENGTH;
 262
 263         /* Allocate and initialize buffer for final image */
 264         buf = malloc(buflen);
 265         if (buf == NULL) {
 266                 ERRS("no memory for buffer: %s\n");
 267                 goto err_close_in;
 268         }
 269         memset(buf, PADDING_BYTE, buflen);
 270
 271         /* Load kernel */
 272         kernel = buf + HDR_LENGTH;
 273         fread(kernel, klen, 1, in);
 274
 275         /* Write magic values */
 276         writel(buf, HDR_OFF_MAGIC1, board->magic1);
 277         writel(buf, HDR_OFF_MAGIC2, board->magic2);
 278         writel(buf, HDR_OFF_MAGIC3, board->magic3);
 279
 280         /* Write header and image length */
 281         writel(buf, HDR_OFF_HDRLEN, HDR_LENGTH);
 282         writel(buf, HDR_OFF_IMAGELEN, klen);
 283
 284         /* Write checksum and static hash */
 285         sha1_csum(kernel, klen, buf + HDR_OFF_CHECKSUM);
 286
 287         switch (board->magic2) {
 288         case 0xa1f0beef:
 289                 writel(buf, HDR_OFF_KERNEL_OFFSET, board->u.mx60.kernel_offset);
 290                 writel(buf, HDR_OFF_RAMDISK_OFFSET, board->u.mx60.ramdisk_offset);
 291                 writel(buf, HDR_OFF_FDT_OFFSET, board->u.mx60.fdt_offset),
 292                 writel(buf, HDR_OFF_UNKNOWN_OFFSET, board->u.mx60.unknown_offset);
 293                 break;
 294
 295         case 0x8e73ed8a:
 296                 memcpy(buf + HDR_OFF_STATICHASH, board->u.statichash, 20);
 297                 break;
 298         }
 299
 300         /* Save finished image */
 301         out = fopen(ofname, "w");
 302         if (out == NULL) {
 303                 ERRS("could not open \"%s\" for writing: %s", ofname);
 304                 goto err_free;
 305         }
 306         fwrite(buf, buflen, 1, out);
 307
 308         ret = EXIT_SUCCESS;
 309
 310         fclose(out);
 311
 312 err_free:
 313         free(buf);
 314
 315 err_close_in:
 316         fclose(in);
 317
 318 err:
 319         return ret;
 320 }