src/backend/libpq/pg_sha2.c

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 *
 * ---------------------------------------------------------------------
 *
 * Interfaces to SHA-256 hashing.
 */
#include "postgres.h"

#include "sha2.h"

#include "libpq/password_hash.h"
#include "libpq/pg_sha2.h"
#include "postmaster/postmaster.h"

static void
to_hex(uint8 b[SHA256_DIGEST_LENGTH], char *s)
{
	static const char *hex = "0123456789abcdef";
	int			q,
				w;

	for (q = 0, w = 0; q < SHA256_DIGEST_LENGTH; q++)
	{
		s[w++] = hex[(b[q] >> 4) & 0x0F];
		s[w++] = hex[b[q] & 0x0F];
	}
	s[w] = '\0';
}


bool
pg_sha256_encrypt(const char *pass, char *salt, size_t salt_len,
				  char *cryptpass)
{
	size_t passwd_len = strlen(pass);
	char *target = palloc(passwd_len + salt_len + 1);
	SHA256_CTX ctx;
	uint8 digest[SHA256_DIGEST_LENGTH];

	memcpy(target, pass, passwd_len);
	memcpy(target + passwd_len, salt, salt_len);
	target[passwd_len + salt_len] = '\0';

	SHA256_Init(&ctx);
	SHA256_Update(&ctx, (uint8 *)target, passwd_len + salt_len);
	SHA256_Final(digest, &ctx);

	strcpy(cryptpass, SHA256_PREFIX);

	to_hex((uint8 *)digest, cryptpass + strlen(SHA256_PREFIX));

	cryptpass[SHA256_PASSWD_LEN] = '\0';

	return true;
}