postgresql/contrib/pgcrypto/pgcrypto.c
Heikki Linnakangas fe0a0b5993 Replace PostmasterRandom() with a stronger source, second attempt.
This adds a new routine, pg_strong_random() for generating random bytes,
for use in both frontend and backend. At the moment, it's only used in
the backend, but the upcoming SCRAM authentication patches need strong
random numbers in libpq as well.

pg_strong_random() is based on, and replaces, the existing implementation
in pgcrypto. It can acquire strong random numbers from a number of sources,
depending on what's available:

- OpenSSL RAND_bytes(), if built with OpenSSL
- On Windows, the native cryptographic functions are used
- /dev/urandom

Unlike the current pgcrypto function, the source is chosen by configure.
That makes it easier to test different implementations, and ensures that
we don't accidentally fall back to a less secure implementation, if the
primary source fails. All of those methods are quite reliable, it would be
pretty surprising for them to fail, so we'd rather find out by failing
hard.

If no strong random source is available, we fall back to using erand48(),
seeded from current timestamp, like PostmasterRandom() was. That isn't
cryptographically secure, but allows us to still work on platforms that
don't have any of the above stronger sources. Because it's not very secure,
the built-in implementation is only used if explicitly requested with
--disable-strong-random.

This replaces the more complicated Fortuna algorithm we used to have in
pgcrypto, which is unfortunate, but all modern platforms have /dev/urandom,
so it doesn't seem worth the maintenance effort to keep that. pgcrypto
functions that require strong random numbers will be disabled with
--disable-strong-random.

Original patch by Magnus Hagander, tons of further work by Michael Paquier
and me.

Discussion: https://www.postgresql.org/message-id/CAB7nPqRy3krN8quR9XujMVVHYtXJ0_60nqgVc6oUk8ygyVkZsA@mail.gmail.com
Discussion: https://www.postgresql.org/message-id/CAB7nPqRWkNYRRPJA7-cF+LfroYV10pvjdz6GNvxk-Eee9FypKA@mail.gmail.com
2016-12-05 13:42:59 +02:00

498 lines
11 KiB
C

/*
* pgcrypto.c
* Various cryptographic stuff for PostgreSQL.
*
* Copyright (c) 2001 Marko Kreen
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* contrib/pgcrypto/pgcrypto.c
*/
#include "postgres.h"
#include <ctype.h>
#include "parser/scansup.h"
#include "utils/backend_random.h"
#include "utils/builtins.h"
#include "utils/uuid.h"
#include "px.h"
#include "px-crypt.h"
#include "pgcrypto.h"
PG_MODULE_MAGIC;
/* private stuff */
typedef int (*PFN) (const char *name, void **res);
static void *find_provider(text *name, PFN pf, char *desc, int silent);
/* SQL function: hash(bytea, text) returns bytea */
PG_FUNCTION_INFO_V1(pg_digest);
Datum
pg_digest(PG_FUNCTION_ARGS)
{
bytea *arg;
text *name;
unsigned len,
hlen;
PX_MD *md;
bytea *res;
name = PG_GETARG_TEXT_P(1);
/* will give error if fails */
md = find_provider(name, (PFN) px_find_digest, "Digest", 0);
hlen = px_md_result_size(md);
res = (text *) palloc(hlen + VARHDRSZ);
SET_VARSIZE(res, hlen + VARHDRSZ);
arg = PG_GETARG_BYTEA_P(0);
len = VARSIZE(arg) - VARHDRSZ;
px_md_update(md, (uint8 *) VARDATA(arg), len);
px_md_finish(md, (uint8 *) VARDATA(res));
px_md_free(md);
PG_FREE_IF_COPY(arg, 0);
PG_FREE_IF_COPY(name, 1);
PG_RETURN_BYTEA_P(res);
}
/* SQL function: hmac(data:bytea, key:bytea, type:text) returns bytea */
PG_FUNCTION_INFO_V1(pg_hmac);
Datum
pg_hmac(PG_FUNCTION_ARGS)
{
bytea *arg;
bytea *key;
text *name;
unsigned len,
hlen,
klen;
PX_HMAC *h;
bytea *res;
name = PG_GETARG_TEXT_P(2);
/* will give error if fails */
h = find_provider(name, (PFN) px_find_hmac, "HMAC", 0);
hlen = px_hmac_result_size(h);
res = (text *) palloc(hlen + VARHDRSZ);
SET_VARSIZE(res, hlen + VARHDRSZ);
arg = PG_GETARG_BYTEA_P(0);
key = PG_GETARG_BYTEA_P(1);
len = VARSIZE(arg) - VARHDRSZ;
klen = VARSIZE(key) - VARHDRSZ;
px_hmac_init(h, (uint8 *) VARDATA(key), klen);
px_hmac_update(h, (uint8 *) VARDATA(arg), len);
px_hmac_finish(h, (uint8 *) VARDATA(res));
px_hmac_free(h);
PG_FREE_IF_COPY(arg, 0);
PG_FREE_IF_COPY(key, 1);
PG_FREE_IF_COPY(name, 2);
PG_RETURN_BYTEA_P(res);
}
/* SQL function: pg_gen_salt(text) returns text */
PG_FUNCTION_INFO_V1(pg_gen_salt);
Datum
pg_gen_salt(PG_FUNCTION_ARGS)
{
text *arg0 = PG_GETARG_TEXT_PP(0);
int len;
char buf[PX_MAX_SALT_LEN + 1];
text_to_cstring_buffer(arg0, buf, sizeof(buf));
len = px_gen_salt(buf, buf, 0);
if (len < 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("gen_salt: %s", px_strerror(len))));
PG_FREE_IF_COPY(arg0, 0);
PG_RETURN_TEXT_P(cstring_to_text_with_len(buf, len));
}
/* SQL function: pg_gen_salt(text, int4) returns text */
PG_FUNCTION_INFO_V1(pg_gen_salt_rounds);
Datum
pg_gen_salt_rounds(PG_FUNCTION_ARGS)
{
text *arg0 = PG_GETARG_TEXT_PP(0);
int rounds = PG_GETARG_INT32(1);
int len;
char buf[PX_MAX_SALT_LEN + 1];
text_to_cstring_buffer(arg0, buf, sizeof(buf));
len = px_gen_salt(buf, buf, rounds);
if (len < 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("gen_salt: %s", px_strerror(len))));
PG_FREE_IF_COPY(arg0, 0);
PG_RETURN_TEXT_P(cstring_to_text_with_len(buf, len));
}
/* SQL function: pg_crypt(psw:text, salt:text) returns text */
PG_FUNCTION_INFO_V1(pg_crypt);
Datum
pg_crypt(PG_FUNCTION_ARGS)
{
text *arg0 = PG_GETARG_TEXT_PP(0);
text *arg1 = PG_GETARG_TEXT_PP(1);
char *buf0,
*buf1,
*cres,
*resbuf;
text *res;
buf0 = text_to_cstring(arg0);
buf1 = text_to_cstring(arg1);
resbuf = palloc0(PX_MAX_CRYPT);
cres = px_crypt(buf0, buf1, resbuf, PX_MAX_CRYPT);
pfree(buf0);
pfree(buf1);
if (cres == NULL)
ereport(ERROR,
(errcode(ERRCODE_EXTERNAL_ROUTINE_INVOCATION_EXCEPTION),
errmsg("crypt(3) returned NULL")));
res = cstring_to_text(cres);
pfree(resbuf);
PG_FREE_IF_COPY(arg0, 0);
PG_FREE_IF_COPY(arg1, 1);
PG_RETURN_TEXT_P(res);
}
/* SQL function: pg_encrypt(bytea, bytea, text) returns bytea */
PG_FUNCTION_INFO_V1(pg_encrypt);
Datum
pg_encrypt(PG_FUNCTION_ARGS)
{
int err;
bytea *data,
*key,
*res;
text *type;
PX_Combo *c;
unsigned dlen,
klen,
rlen;
type = PG_GETARG_TEXT_P(2);
c = find_provider(type, (PFN) px_find_combo, "Cipher", 0);
data = PG_GETARG_BYTEA_P(0);
key = PG_GETARG_BYTEA_P(1);
dlen = VARSIZE(data) - VARHDRSZ;
klen = VARSIZE(key) - VARHDRSZ;
rlen = px_combo_encrypt_len(c, dlen);
res = palloc(VARHDRSZ + rlen);
err = px_combo_init(c, (uint8 *) VARDATA(key), klen, NULL, 0);
if (!err)
err = px_combo_encrypt(c, (uint8 *) VARDATA(data), dlen,
(uint8 *) VARDATA(res), &rlen);
px_combo_free(c);
PG_FREE_IF_COPY(data, 0);
PG_FREE_IF_COPY(key, 1);
PG_FREE_IF_COPY(type, 2);
if (err)
{
pfree(res);
ereport(ERROR,
(errcode(ERRCODE_EXTERNAL_ROUTINE_INVOCATION_EXCEPTION),
errmsg("encrypt error: %s", px_strerror(err))));
}
SET_VARSIZE(res, VARHDRSZ + rlen);
PG_RETURN_BYTEA_P(res);
}
/* SQL function: pg_decrypt(bytea, bytea, text) returns bytea */
PG_FUNCTION_INFO_V1(pg_decrypt);
Datum
pg_decrypt(PG_FUNCTION_ARGS)
{
int err;
bytea *data,
*key,
*res;
text *type;
PX_Combo *c;
unsigned dlen,
klen,
rlen;
type = PG_GETARG_TEXT_P(2);
c = find_provider(type, (PFN) px_find_combo, "Cipher", 0);
data = PG_GETARG_BYTEA_P(0);
key = PG_GETARG_BYTEA_P(1);
dlen = VARSIZE(data) - VARHDRSZ;
klen = VARSIZE(key) - VARHDRSZ;
rlen = px_combo_decrypt_len(c, dlen);
res = palloc(VARHDRSZ + rlen);
err = px_combo_init(c, (uint8 *) VARDATA(key), klen, NULL, 0);
if (!err)
err = px_combo_decrypt(c, (uint8 *) VARDATA(data), dlen,
(uint8 *) VARDATA(res), &rlen);
px_combo_free(c);
if (err)
ereport(ERROR,
(errcode(ERRCODE_EXTERNAL_ROUTINE_INVOCATION_EXCEPTION),
errmsg("decrypt error: %s", px_strerror(err))));
SET_VARSIZE(res, VARHDRSZ + rlen);
PG_FREE_IF_COPY(data, 0);
PG_FREE_IF_COPY(key, 1);
PG_FREE_IF_COPY(type, 2);
PG_RETURN_BYTEA_P(res);
}
/* SQL function: pg_encrypt_iv(bytea, bytea, bytea, text) returns bytea */
PG_FUNCTION_INFO_V1(pg_encrypt_iv);
Datum
pg_encrypt_iv(PG_FUNCTION_ARGS)
{
int err;
bytea *data,
*key,
*iv,
*res;
text *type;
PX_Combo *c;
unsigned dlen,
klen,
ivlen,
rlen;
type = PG_GETARG_TEXT_P(3);
c = find_provider(type, (PFN) px_find_combo, "Cipher", 0);
data = PG_GETARG_BYTEA_P(0);
key = PG_GETARG_BYTEA_P(1);
iv = PG_GETARG_BYTEA_P(2);
dlen = VARSIZE(data) - VARHDRSZ;
klen = VARSIZE(key) - VARHDRSZ;
ivlen = VARSIZE(iv) - VARHDRSZ;
rlen = px_combo_encrypt_len(c, dlen);
res = palloc(VARHDRSZ + rlen);
err = px_combo_init(c, (uint8 *) VARDATA(key), klen,
(uint8 *) VARDATA(iv), ivlen);
if (!err)
err = px_combo_encrypt(c, (uint8 *) VARDATA(data), dlen,
(uint8 *) VARDATA(res), &rlen);
px_combo_free(c);
if (err)
ereport(ERROR,
(errcode(ERRCODE_EXTERNAL_ROUTINE_INVOCATION_EXCEPTION),
errmsg("encrypt_iv error: %s", px_strerror(err))));
SET_VARSIZE(res, VARHDRSZ + rlen);
PG_FREE_IF_COPY(data, 0);
PG_FREE_IF_COPY(key, 1);
PG_FREE_IF_COPY(iv, 2);
PG_FREE_IF_COPY(type, 3);
PG_RETURN_BYTEA_P(res);
}
/* SQL function: pg_decrypt_iv(bytea, bytea, bytea, text) returns bytea */
PG_FUNCTION_INFO_V1(pg_decrypt_iv);
Datum
pg_decrypt_iv(PG_FUNCTION_ARGS)
{
int err;
bytea *data,
*key,
*iv,
*res;
text *type;
PX_Combo *c;
unsigned dlen,
klen,
rlen,
ivlen;
type = PG_GETARG_TEXT_P(3);
c = find_provider(type, (PFN) px_find_combo, "Cipher", 0);
data = PG_GETARG_BYTEA_P(0);
key = PG_GETARG_BYTEA_P(1);
iv = PG_GETARG_BYTEA_P(2);
dlen = VARSIZE(data) - VARHDRSZ;
klen = VARSIZE(key) - VARHDRSZ;
ivlen = VARSIZE(iv) - VARHDRSZ;
rlen = px_combo_decrypt_len(c, dlen);
res = palloc(VARHDRSZ + rlen);
err = px_combo_init(c, (uint8 *) VARDATA(key), klen,
(uint8 *) VARDATA(iv), ivlen);
if (!err)
err = px_combo_decrypt(c, (uint8 *) VARDATA(data), dlen,
(uint8 *) VARDATA(res), &rlen);
px_combo_free(c);
if (err)
ereport(ERROR,
(errcode(ERRCODE_EXTERNAL_ROUTINE_INVOCATION_EXCEPTION),
errmsg("decrypt_iv error: %s", px_strerror(err))));
SET_VARSIZE(res, VARHDRSZ + rlen);
PG_FREE_IF_COPY(data, 0);
PG_FREE_IF_COPY(key, 1);
PG_FREE_IF_COPY(iv, 2);
PG_FREE_IF_COPY(type, 3);
PG_RETURN_BYTEA_P(res);
}
/* SQL function: pg_random_bytes(int4) returns bytea */
PG_FUNCTION_INFO_V1(pg_random_bytes);
Datum
pg_random_bytes(PG_FUNCTION_ARGS)
{
#ifdef HAVE_STRONG_RANDOM
int len = PG_GETARG_INT32(0);
bytea *res;
if (len < 1 || len > 1024)
ereport(ERROR,
(errcode(ERRCODE_EXTERNAL_ROUTINE_INVOCATION_EXCEPTION),
errmsg("Length not in range")));
res = palloc(VARHDRSZ + len);
SET_VARSIZE(res, VARHDRSZ + len);
/* generate result */
if (!pg_strong_random(VARDATA(res), len))
px_THROW_ERROR(PXE_NO_RANDOM);
PG_RETURN_BYTEA_P(res);
#else
px_THROW_ERROR(PXE_NO_RANDOM);
#endif
}
/* SQL function: gen_random_uuid() returns uuid */
PG_FUNCTION_INFO_V1(pg_random_uuid);
Datum
pg_random_uuid(PG_FUNCTION_ARGS)
{
uint8 *buf = (uint8 *) palloc(UUID_LEN);
/*
* Generate random bits. pg_backend_random() will do here, we don't
* promis UUIDs to be cryptographically random, when built with
* --disable-strong-random.
*/
if (!pg_backend_random((char *) buf, UUID_LEN))
px_THROW_ERROR(PXE_NO_RANDOM);
/*
* Set magic numbers for a "version 4" (pseudorandom) UUID, see
* http://tools.ietf.org/html/rfc4122#section-4.4
*/
buf[6] = (buf[6] & 0x0f) | 0x40; /* "version" field */
buf[8] = (buf[8] & 0x3f) | 0x80; /* "variant" field */
PG_RETURN_UUID_P((pg_uuid_t *) buf);
}
static void *
find_provider(text *name,
PFN provider_lookup,
char *desc, int silent)
{
void *res;
char *buf;
int err;
buf = downcase_truncate_identifier(VARDATA(name),
VARSIZE(name) - VARHDRSZ,
false);
err = provider_lookup(buf, &res);
if (err && !silent)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("Cannot use \"%s\": %s", buf, px_strerror(err))));
pfree(buf);
return err ? NULL : res;
}