OpenWrt – Rev 3
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/*
* Copyright (C) 2016 Felix Fietkau <nbd@nbd.name>
*
* 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
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <sys/types.h>
#include <stdio.h>
#include <getopt.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "fwimage.h"
#include "utils.h"
#include "crc32.h"
#define METADATA_MAXLEN 30 * 1024
#define SIGNATURE_MAXLEN 1 * 1024
#define BUFLEN (METADATA_MAXLEN + SIGNATURE_MAXLEN + 1024)
enum {
MODE_DEFAULT = -1,
MODE_EXTRACT = 0,
MODE_APPEND = 1,
};
struct data_buf {
char *cur;
char *prev;
int cur_len;
int file_len;
};
static FILE *signature_file, *metadata_file, *firmware_file;
static int file_mode = MODE_DEFAULT;
static bool truncate_file;
static bool quiet = false;
static uint32_t crc_table[256];
#define msg(...) \
do { \
if (!quiet) \
fprintf(stderr, __VA_ARGS__); \
} while (0)
static int
usage(const char *progname)
{
fprintf(stderr, "Usage: %s <options> <firmware>\n"
"\n"
"Options:\n"
" -S <file>: Append signature file to firmware image\n"
" -I <file>: Append metadata file to firmware image\n"
" -s <file>: Extract signature file from firmware image\n"
" -i <file>: Extract metadata file from firmware image\n"
" -t: Remove extracted chunks from firmare image (using -s, -i)\n"
" -q: Quiet (suppress error messages)\n"
"\n", progname);
return 1;
}
static FILE *
open_file(const char *name, bool write)
{
FILE *ret;
if (!strcmp(name, "-"))
return write ? stdout : stdin;
ret = fopen(name, write ? "w" : "r+");
if (!ret && !write)
ret = fopen(name, "r");
return ret;
}
static int
set_file(FILE **file, const char *name, int mode)
{
if (file_mode < 0)
file_mode = mode;
else if (file_mode != mode) {
msg("Error: mixing appending and extracting data is not supported\n");
return 1;
}
if (*file) {
msg("Error: the same append/extract option cannot be used multiple times\n");
return 1;
}
*file = open_file(name, mode == MODE_EXTRACT);
return !*file;
}
static void
trailer_update_crc(struct fwimage_trailer *tr, void *buf, int len)
{
tr->crc32 = cpu_to_be32(crc32_block(be32_to_cpu(tr->crc32), buf, len, crc_table));
}
static int
append_data(FILE *in, FILE *out, struct fwimage_trailer *tr, int maxlen)
{
while (1) {
char buf[512];
int len;
len = fread(buf, 1, sizeof(buf), in);
if (!len)
break;
maxlen -= len;
if (maxlen < 0)
return 1;
tr->size += len;
trailer_update_crc(tr, buf, len);
fwrite(buf, len, 1, out);
}
return 0;
}
static void
append_trailer(FILE *out, struct fwimage_trailer *tr)
{
tr->size = cpu_to_be32(tr->size);
fwrite(tr, sizeof(*tr), 1, out);
trailer_update_crc(tr, tr, sizeof(*tr));
}
static int
add_metadata(struct fwimage_trailer *tr)
{
struct fwimage_header hdr = {};
tr->type = FWIMAGE_INFO;
tr->size = sizeof(hdr) + sizeof(*tr);
trailer_update_crc(tr, &hdr, sizeof(hdr));
fwrite(&hdr, sizeof(hdr), 1, firmware_file);
if (append_data(metadata_file, firmware_file, tr, METADATA_MAXLEN))
return 1;
append_trailer(firmware_file, tr);
return 0;
}
static int
add_signature(struct fwimage_trailer *tr)
{
if (!signature_file)
return 0;
tr->type = FWIMAGE_SIGNATURE;
tr->size = sizeof(*tr);
if (append_data(signature_file, firmware_file, tr, SIGNATURE_MAXLEN))
return 1;
append_trailer(firmware_file, tr);
return 0;
}
static int
add_data(const char *name)
{
struct fwimage_trailer tr = {
.magic = cpu_to_be32(FWIMAGE_MAGIC),
.crc32 = ~0,
};
int file_len = 0;
int ret = 0;
firmware_file = fopen(name, "r+");
if (!firmware_file) {
msg("Failed to open firmware file\n");
return 1;
}
while (1) {
char buf[512];
int len;
len = fread(buf, 1, sizeof(buf), firmware_file);
if (!len)
break;
file_len += len;
trailer_update_crc(&tr, buf, len);
}
if (metadata_file)
ret = add_metadata(&tr);
else if (signature_file)
ret = add_signature(&tr);
if (ret) {
fflush(firmware_file);
ftruncate(fileno(firmware_file), file_len);
}
return ret;
}
static void
remove_tail(struct data_buf *dbuf, int len)
{
dbuf->cur_len -= len;
dbuf->file_len -= len;
if (dbuf->cur_len)
return;
free(dbuf->cur);
dbuf->cur = dbuf->prev;
dbuf->prev = NULL;
dbuf->cur_len = BUFLEN;
}
static int
extract_tail(struct data_buf *dbuf, void *dest, int len)
{
int cur_len = dbuf->cur_len;
if (!dbuf->cur)
return 1;
if (cur_len >= len)
cur_len = len;
memcpy(dest + (len - cur_len), dbuf->cur + dbuf->cur_len - cur_len, cur_len);
remove_tail(dbuf, cur_len);
cur_len = len - cur_len;
if (cur_len && !dbuf->cur)
return 1;
memcpy(dest, dbuf->cur + dbuf->cur_len - cur_len, cur_len);
remove_tail(dbuf, cur_len);
return 0;
}
static uint32_t
tail_crc32(struct data_buf *dbuf, uint32_t crc32)
{
if (dbuf->prev)
crc32 = crc32_block(crc32, dbuf->prev, BUFLEN, crc_table);
return crc32_block(crc32, dbuf->cur, dbuf->cur_len, crc_table);
}
static int
validate_metadata(struct fwimage_header *hdr, int data_len)
{
if (hdr->version != 0)
return 1;
return 0;
}
static int
extract_data(const char *name)
{
struct fwimage_header *hdr;
struct fwimage_trailer tr;
struct data_buf dbuf = {};
uint32_t crc32 = ~0;
int ret = 1;
void *buf;
firmware_file = open_file(name, false);
if (!firmware_file) {
msg("Failed to open firmware file\n");
return 1;
}
if (truncate_file && firmware_file == stdin) {
msg("Cannot truncate file when reading from stdin\n");
return 1;
}
buf = malloc(BUFLEN);
if (!buf)
return 1;
do {
char *tmp = dbuf.cur;
dbuf.cur = dbuf.prev;
dbuf.prev = tmp;
if (dbuf.cur)
crc32 = crc32_block(crc32, dbuf.cur, BUFLEN, crc_table);
else
dbuf.cur = malloc(BUFLEN);
if (!dbuf.cur)
goto out;
dbuf.cur_len = fread(dbuf.cur, 1, BUFLEN, firmware_file);
dbuf.file_len += dbuf.cur_len;
} while (dbuf.cur_len == BUFLEN);
while (1) {
int data_len;
if (extract_tail(&dbuf, &tr, sizeof(tr)))
break;
data_len = be32_to_cpu(tr.size) - sizeof(tr);
if (tr.magic != cpu_to_be32(FWIMAGE_MAGIC)) {
msg("Data not found\n");
break;
}
if (be32_to_cpu(tr.crc32) != tail_crc32(&dbuf, crc32)) {
msg("CRC error\n");
break;
}
if (data_len > BUFLEN) {
msg("Size error\n");
break;
}
extract_tail(&dbuf, buf, data_len);
if (tr.type == FWIMAGE_SIGNATURE) {
if (!signature_file)
continue;
fwrite(buf, data_len, 1, signature_file);
ret = 0;
break;
} else if (tr.type == FWIMAGE_INFO) {
if (!metadata_file)
break;
hdr = buf;
data_len -= sizeof(*hdr);
if (validate_metadata(hdr, data_len))
continue;
fwrite(hdr + 1, data_len, 1, metadata_file);
ret = 0;
break;
} else {
continue;
}
}
if (!ret && truncate_file)
ftruncate(fileno(firmware_file), dbuf.file_len);
out:
free(buf);
free(dbuf.cur);
free(dbuf.prev);
return ret;
}
static void cleanup(void)
{
if (signature_file)
fclose(signature_file);
if (metadata_file)
fclose(metadata_file);
if (firmware_file)
fclose(firmware_file);
}
int main(int argc, char **argv)
{
const char *progname = argv[0];
int ret, ch;
crc32_filltable(crc_table);
while ((ch = getopt(argc, argv, "i:I:qs:S:t")) != -1) {
ret = 0;
switch(ch) {
case 'S':
ret = set_file(&signature_file, optarg, MODE_APPEND);
break;
case 'I':
ret = set_file(&metadata_file, optarg, MODE_APPEND);
break;
case 's':
ret = set_file(&signature_file, optarg, MODE_EXTRACT);
break;
case 'i':
ret = set_file(&metadata_file, optarg, MODE_EXTRACT);
break;
case 't':
truncate_file = true;
break;
case 'q':
quiet = true;
break;
}
if (ret)
goto out;
}
if (optind >= argc) {
ret = usage(progname);
goto out;
}
if (file_mode == MODE_DEFAULT) {
ret = usage(progname);
goto out;
}
if (signature_file && metadata_file) {
msg("Cannot append/extract metadata and signature in one run\n");
return 1;
}
if (file_mode)
ret = add_data(argv[optind]);
else
ret = extract_data(argv[optind]);
out:
cleanup();
return ret;
}