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/*
* Stand-alone tool to access the Puzzles obfuscation algorithm.
*
* To deobfuscate, use "obfusc -d":
*
* obfusc -d reads binary data from stdin, writes to stdout
* obfusc -d <hex string> works on the given hex string instead of stdin
* obfusc -d -h writes a hex string instead of binary to stdout
*
* To obfuscate, "obfusc -e":
*
* obfusc -e reads binary from stdin, writes hex to stdout
* obfusc -e <hex string> works on the given hex string instead of stdin
* obfusc -e -b writes binary instead of text to stdout
*
* The default output format is hex for -e and binary for -d
* because that's the way obfuscation is generally used in
* Puzzles. Either of -b and -h can always be specified to set it
* explicitly.
*
* Data read from standard input is assumed always to be binary;
* data provided on the command line is taken to be hex.
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <errno.h>
#include "puzzles.h"
static bool self_tests(void)
{
bool ok = true;
#define FAILED (ok = false, "failed")
/*
* A few simple test vectors for the obfuscator.
*
* First test: the 28-bit stream 1234567. This divides up
* into 1234 and 567[0]. The SHA of 56 70 30 (appending
* "0") is 15ce8ab946640340bbb99f3f48fd2c45d1a31d30. Thus,
* we XOR the 16-bit string 15CE into the input 1234 to get
* 07FA. Next, we SHA that with "0": the SHA of 07 FA 30 is
* 3370135c5e3da4fed937adc004a79533962b6391. So we XOR the
* 12-bit string 337 into the input 567 to get 650. Thus
* our output is 07FA650.
*/
{
unsigned char bmp1[] = "\x12\x34\x56\x70";
obfuscate_bitmap(bmp1, 28, false);
printf("test 1 encode: %s\n",
memcmp(bmp1, "\x07\xfa\x65\x00", 4) ? FAILED : "passed");
obfuscate_bitmap(bmp1, 28, true);
printf("test 1 decode: %s\n",
memcmp(bmp1, "\x12\x34\x56\x70", 4) ? FAILED : "passed");
}
/*
* Second test: a long string to make sure we switch from
* one SHA to the next correctly. My input string this time
* is simply fifty bytes of zeroes.
*/
{
unsigned char bmp2[50];
unsigned char bmp2a[50];
memset(bmp2, 0, 50);
memset(bmp2a, 0, 50);
obfuscate_bitmap(bmp2, 50 * 8, false);
/*
* SHA of twenty-five zero bytes plus "0" is
* b202c07b990c01f6ff2d544707f60e506019b671. SHA of
* twenty-five zero bytes plus "1" is
* fcb1d8b5a2f6b592fe6780b36aa9d65dd7aa6db9. Thus our
* first half becomes
* b202c07b990c01f6ff2d544707f60e506019b671fcb1d8b5a2.
*
* SHA of that lot plus "0" is
* 10b0af913db85d37ca27f52a9f78bba3a80030db. SHA of the
* same string plus "1" is
* 3d01d8df78e76d382b8106f480135a1bc751d725. So the
* second half becomes
* 10b0af913db85d37ca27f52a9f78bba3a80030db3d01d8df78.
*/
printf("test 2 encode: %s\n",
memcmp(bmp2, "\xb2\x02\xc0\x7b\x99\x0c\x01\xf6\xff\x2d\x54"
"\x47\x07\xf6\x0e\x50\x60\x19\xb6\x71\xfc\xb1\xd8"
"\xb5\xa2\x10\xb0\xaf\x91\x3d\xb8\x5d\x37\xca\x27"
"\xf5\x2a\x9f\x78\xbb\xa3\xa8\x00\x30\xdb\x3d\x01"
"\xd8\xdf\x78", 50) ? FAILED : "passed");
obfuscate_bitmap(bmp2, 50 * 8, true);
printf("test 2 decode: %s\n",
memcmp(bmp2, bmp2a, 50) ? FAILED : "passed");
}
#undef FAILED
return ok;
}
int main(int argc, char **argv)
{
enum { BINARY, DEFAULT, HEX } outputmode = DEFAULT;
char *inhex = NULL;
unsigned char *data;
int datalen;
enum { UNKNOWN, DECODE, ENCODE, SELFTEST } mode = UNKNOWN;
bool doing_opts = true;
while (--argc > 0) {
char *p = *++argv;
if (doing_opts && *p == '-') {
if (!strcmp(p, "--")) {
doing_opts = 0;
continue;
}
p++;
while (*p) {
switch (*p) {
case 'e':
mode = ENCODE;
break;
case 'd':
mode = DECODE;
break;
case 't':
mode = SELFTEST;
break;
case 'b':
outputmode = BINARY;
break;
case 'h':
outputmode = HEX;
break;
default:
fprintf(stderr, "obfusc: unrecognised option '-%c'\n",
*p);
return 1;
}
p++;
}
} else {
if (!inhex) {
inhex = p;
} else {
fprintf(stderr, "obfusc: expected at most one argument\n");
return 1;
}
}
}
if (mode == UNKNOWN) {
fprintf(stderr, "usage: obfusc < -e | -d > [ -b | -h ] [hex data]\n");
fprintf(stderr, " or: obfusc -t to run self-tests\n");
return 0;
}
if (mode == SELFTEST) {
return self_tests() ? 0 : 1;
}
if (outputmode == DEFAULT)
outputmode = (mode == DECODE ? BINARY : HEX);
if (inhex) {
datalen = strlen(inhex) / 2;
data = hex2bin(inhex, datalen);
} else {
int datasize = 4096;
datalen = 0;
data = snewn(datasize, unsigned char);
while (1) {
int ret = fread(data + datalen, 1, datasize - datalen, stdin);
if (ret < 0) {
fprintf(stderr, "obfusc: read: %s\n", strerror(errno));
return 1;
} else if (ret == 0) {
break;
} else {
datalen += ret;
if (datasize - datalen < 4096) {
datasize = datalen * 5 / 4 + 4096;
data = sresize(data, datasize, unsigned char);
}
}
}
}
obfuscate_bitmap(data, datalen * 8, mode == DECODE);
if (outputmode == BINARY) {
int ret = fwrite(data, 1, datalen, stdout);
if (ret < 0) {
fprintf(stderr, "obfusc: write: %s\n", strerror(errno));
return 1;
}
} else {
int i;
for (i = 0; i < datalen; i++)
printf("%02x", data[i]);
printf("\n");
}
return 0;
}
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