GoPro FW extractor.

goprofwparser.c

/* This tool extracts the sections of a supplied GoPro
 * firmware image.
 *
 * It creates the following files in the current directory:
 * bst.bin, bld.bin, pri.bin, rom.bin, dsp.bin
 *
 * It also shows the expected CRC32 checksum of the section and shows
 * where it will be written on the device, you can use this address as
 * ROM address and load address in IDA Pro.
 *
 *
 * Copyright (c) 2012, Thomas Roth <code@stacksmashing.net>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met: 
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer. 
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution. 
 *
 *    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 *    ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 *    WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *    DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 *    ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 *    (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 *    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 *    ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *    (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *    SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *    The views and conclusions contained in the software and documentation are those
 *    of the authors and should not be interpreted as representing official policies, 
 *    either expressed or implied, of the FreeBSD Project.
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <inttypes.h>

typedef struct {
	/* According to pieces in the firmware 
	 * (1.1.54, bld.bin, 0xc001dcfc),
	 * there could also be rmd, bak and pba sections.
	 */
	/* 0x00 */ uint32_t bst_section_start;
	/* 0x04 */ uint32_t bst_section_end;
	/* 0x08 */ uint32_t bld_section_start;
	/* 0x0c */ uint32_t bld_section_end;
	/* 0x10 */ uint32_t unknown_0;
	/* 0x14 */ uint32_t unknown_1;
	/* 0x18 */ uint32_t pri_section_start;
	/* 0x1C */ uint32_t pri_section_end;
	/* 0x20 */ uint32_t unknown_2;
	/* 0x24 */ uint32_t unknown_3;
	/* 0x28 */ uint32_t rom_section_start;
	/* 0x2c */ uint32_t rom_section_end;
	/* 0x30 */ uint32_t dsp_section_start;
	/* 0x34 */ uint32_t dsp_section_end;
} gopro_fw_file_header;

typedef struct {
	/* 0x00 */ uint32_t crc32;
	/* 0x04 */ uint32_t version;
	/* 0x08 */ uint8_t build_date_day;
	/* 0x09 */ uint8_t build_date_month;
	/* 0x10 */ uint16_t build_date_year;
	/* 0x12 */ uint32_t length;
	/* 0x16 */ uint32_t loading_address;
	/* 0x20 */ uint32_t flags;
	/* 0x24 */ uint32_t magic;
	/* The image starts 0x100 bytes after the  beginning of the header. */
} gopro_fw_section_header;

void read_bytes_from_file(void *dst, FILE *src, size_t lng) {
	if(fread(dst, lng, 1, src) != 1) {
		fprintf(stderr, "Failed to read 0x%08X bytes.\n", lng);
		exit(EXIT_FAILURE);
	}
}

void error_seek(FILE *f, size_t offset, int whence) {
	if(fseek(f, offset, SEEK_SET) != 0) {
		fprintf(stderr, "Failed to seek to %d\n", offset);
		exit(EXIT_FAILURE);
	}
}

void write_bytes_to_file(char *dst_name, FILE *src, int len) {
	FILE *dst = fopen(dst_name, "w");
	int bytes_remaining = len;
	/* Export in 1024 byte chunks */
	char tmp_buffer[1024];
	while(bytes_remaining) {
		int r = bytes_remaining > 1024 ? 1024 : bytes_remaining;
		if(fread(tmp_buffer, r, 1, src) != 1) {
			fprintf(stderr, "Failed to read section.");
			exit(EXIT_FAILURE);
		}
		if(fwrite(tmp_buffer, r, 1, dst) != 1) {
			fprintf(stderr, "Failed to write section.");
			exit(EXIT_FAILURE);
		}

		bytes_remaining -= r;
	}
}

void export_section(char *name, char *fname, FILE *src, uint32_t start, uint32_t end) {
	if(start) {
		printf("Exporting %s section...\n", name);
	} else {
		printf("No %s section found.\n", name);
		return;
	}
	error_seek(src, start, SEEK_SET);
	gopro_fw_section_header sh;
	read_bytes_from_file(&sh, src, sizeof(sh));
	printf("\tBeginning : %d\n", start);
	printf("\tEnd       : %d\n", end);
	printf("\tCRC32     : 0x%08X\n", sh.crc32);
	printf("\tVersion   : %d.%d\n",
			(sh.version >> 16),
			sh.version & 0x000000FF);
	printf("\tBuild date: %02d.%02d.%d\n",
			sh.build_date_day,
			sh.build_date_month,
			sh.build_date_year);
	printf("\tLength    : %d (0x%08X)\n", sh.length, sh.length);
	printf("\tAddress   : 0x%08X\n", sh.loading_address);
	printf("\tFlags     : 0x%08X\n", sh.flags);
	printf("\tMagic     : 0x%08X\n", sh.magic);
	printf("Writing to %s...\n", fname);
	// Go to section start + 0x100, this is where the actual
	// image contents begins.
	error_seek(src, start+0x100, SEEK_SET);
	write_bytes_to_file(fname, src, sh.length);
	printf("Done.\n");
}

int main(int argc, char *argv[]) {
	if(argc < 2) {
		fprintf(
			stderr,
			"Usage: %s [firmware_file]\n",
			argv[0]);
		exit(EXIT_FAILURE);
	}

	FILE *firmware_file = fopen(argv[1], "r");
	if(!firmware_file) {
		fprintf(stderr, "Failed to open %s\n", argv[1]);
		exit(EXIT_FAILURE);
	}

	gopro_fw_file_header fh;
	read_bytes_from_file(&fh, firmware_file, sizeof(fh));
	export_section(
		"BST",
		"bst.bin",
		firmware_file,
		fh.bst_section_start,
		fh.bst_section_end);
	export_section(
		"BLD",
		"bld.bin",
		firmware_file,
		fh.bld_section_start,
		fh.bld_section_end);
	export_section(
		"PRI",
		"pri.bin",
		firmware_file,
		fh.pri_section_start,
		fh.pri_section_end);
	
	export_section(
		"ROM",
		"rom.bin",
		firmware_file,
		fh.rom_section_start,
		fh.rom_section_end);
	
	export_section(
		"DSP",
		"dsp.bin",
		firmware_file,
		fh.dsp_section_start,
		fh.dsp_section_end);
	exit(EXIT_SUCCESS);	
}