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/*-------------------------------------------------------------------------
*
* md5_common.c
* Routines shared between all MD5 implementations used for encrypted
* passwords.
*
* Sverre H. Huseby <sverrehu@online.no>
*
* Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/common/md5_common.c
*
*-------------------------------------------------------------------------
*/
#ifndef FRONTEND
#include "postgres.h"
#else
#include "postgres_fe.h"
#endif
#include "common/cryptohash.h"
#include "common/md5.h"
static void
bytesToHex(uint8 b[16], char *s)
{
static const char *hex = "0123456789abcdef";
int q,
w;
for (q = 0, w = 0; q < 16; q++)
{
s[w++] = hex[(b[q] >> 4) & 0x0F];
s[w++] = hex[b[q] & 0x0F];
}
s[w] = '\0';
}
/*
* pg_md5_hash
*
* Calculates the MD5 sum of the bytes in a buffer.
*
* SYNOPSIS #include "md5.h"
* int pg_md5_hash(const void *buff, size_t len, char *hexsum)
*
* INPUT buff the buffer containing the bytes that you want
* the MD5 sum of.
* len number of bytes in the buffer.
*
* OUTPUT hexsum the MD5 sum as a '\0'-terminated string of
* hexadecimal digits. an MD5 sum is 16 bytes long.
* each byte is represented by two hexadecimal
* characters. you thus need to provide an array
* of 33 characters, including the trailing '\0'.
*
* RETURNS false on failure (out of memory for internal buffers
* or MD5 computation failure) or true on success.
*
* STANDARDS MD5 is described in RFC 1321.
*
* AUTHOR Sverre H. Huseby <sverrehu@online.no>
*
*/
bool
pg_md5_hash(const void *buff, size_t len, char *hexsum)
{
uint8 sum[MD5_DIGEST_LENGTH];
pg_cryptohash_ctx *ctx;
ctx = pg_cryptohash_create(PG_MD5);
if (ctx == NULL)
return false;
if (pg_cryptohash_init(ctx) < 0 ||
pg_cryptohash_update(ctx, buff, len) < 0 ||
pg_cryptohash_final(ctx, sum, sizeof(sum)) < 0)
{
pg_cryptohash_free(ctx);
return false;
}
bytesToHex(sum, hexsum);
pg_cryptohash_free(ctx);
return true;
}
bool
pg_md5_binary(const void *buff, size_t len, void *outbuf)
{
pg_cryptohash_ctx *ctx;
ctx = pg_cryptohash_create(PG_MD5);
if (ctx == NULL)
return false;
if (pg_cryptohash_init(ctx) < 0 ||
pg_cryptohash_update(ctx, buff, len) < 0 ||
pg_cryptohash_final(ctx, outbuf, MD5_DIGEST_LENGTH) < 0)
{
pg_cryptohash_free(ctx);
return false;
}
pg_cryptohash_free(ctx);
return true;
}
/*
* Computes MD5 checksum of "passwd" (a null-terminated string) followed
* by "salt" (which need not be null-terminated).
*
* Output format is "md5" followed by a 32-hex-digit MD5 checksum.
* Hence, the output buffer "buf" must be at least 36 bytes long.
*
* Returns true if okay, false on error (out of memory).
*/
bool
pg_md5_encrypt(const char *passwd, const char *salt, size_t salt_len,
char *buf)
{
size_t passwd_len = strlen(passwd);
/* +1 here is just to avoid risk of unportable malloc(0) */
char *crypt_buf = malloc(passwd_len + salt_len + 1);
bool ret;
if (!crypt_buf)
return false;
/*
* Place salt at the end because it may be known by users trying to crack
* the MD5 output.
*/
memcpy(crypt_buf, passwd, passwd_len);
memcpy(crypt_buf + passwd_len, salt, salt_len);
strcpy(buf, "md5");
ret = pg_md5_hash(crypt_buf, passwd_len + salt_len, buf + 3);
free(crypt_buf);
return ret;
}
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