crypt_private.c
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/*
* This code exists for the sole purpose to serve as another implementation
* of the "private" password hashing method implemened in PasswordHash.php
* and thus to confirm that these password hashes are indeed calculated as
* intended.
*
* Other uses of this code are discouraged. There are much better password
* hashing algorithms available to C programmers; one of those is bcrypt:
*
* http://www.openwall.com/crypt/
*
* Written by Solar Designer <solar at openwall.com> in 2005 and placed in
* the public domain.
*
* There's absolutely no warranty.
*/
#include <string.h>
#include <openssl/md5.h>
#ifdef TEST
#include <stdio.h>
#endif
static char *itoa64 =
"./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
static void encode64(char *dst, char *src, int count)
{
int i, value;
i = 0;
do {
value = (unsigned char)src[i++];
*dst++ = itoa64[value & 0x3f];
if (i < count)
value |= (unsigned char)src[i] << 8;
*dst++ = itoa64[(value >> 6) & 0x3f];
if (i++ >= count)
break;
if (i < count)
value |= (unsigned char)src[i] << 16;
*dst++ = itoa64[(value >> 12) & 0x3f];
if (i++ >= count)
break;
*dst++ = itoa64[(value >> 18) & 0x3f];
} while (i < count);
}
char *crypt_private(char *password, char *setting)
{
static char output[35];
MD5_CTX ctx;
char hash[MD5_DIGEST_LENGTH];
char *p, *salt;
int count_log2, length, count;
strcpy(output, "*0");
if (!strncmp(setting, output, 2))
output[1] = '1';
if (strncmp(setting, "$P$", 3))
return output;
p = strchr(itoa64, setting[3]);
if (!p)
return output;
count_log2 = p - itoa64;
if (count_log2 < 7 || count_log2 > 30)
return output;
salt = setting + 4;
if (strlen(salt) < 8)
return output;
length = strlen(password);
MD5_Init(&ctx);
MD5_Update(&ctx, salt, 8);
MD5_Update(&ctx, password, length);
MD5_Final(hash, &ctx);
count = 1 << count_log2;
do {
MD5_Init(&ctx);
MD5_Update(&ctx, hash, MD5_DIGEST_LENGTH);
MD5_Update(&ctx, password, length);
MD5_Final(hash, &ctx);
} while (--count);
memcpy(output, setting, 12);
encode64(&output[12], hash, MD5_DIGEST_LENGTH);
return output;
}
#ifdef TEST
int main(int argc, char **argv)
{
if (argc != 3) return 1;
puts(crypt_private(argv[1], argv[2]));
return 0;
}
#endif