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postgresql/contrib/pgcrypto/pgp-pubkey.c
Michael Paquier ca7f8e2b86 Remove custom memory allocation layer in pgcrypto 
PX_OWN_ALLOC was intended as a way to disable the use of palloc(), and
over the time new palloc() or equivalent calls have been added like in
32984d8, making this extra layer losing its original purpose.  This
simplifies on the way some code paths to use palloc0() rather than
palloc() followed by memset(0).

Author: Daniel Gustafsson
Discussion: https://postgr.es/m/A5BFAA1A-B2E8-4CBC-895E-7B1B9475A527@yesql.se
2020-09-25 10:25:55 +09:00

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/*
* pgp-pubkey.c
* Read public or secret key.
*
* Copyright (c) 2005 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/pgp-pubkey.c
*/
#include "postgres.h"
#include "mbuf.h"
#include "pgp.h"
#include "px.h"
int
pgp_key_alloc(PGP_PubKey **pk_p)
{
PGP_PubKey *pk;
pk = palloc0(sizeof(*pk));
*pk_p = pk;
return 0;
}
void
pgp_key_free(PGP_PubKey *pk)
{
if (pk == NULL)
return;
switch (pk->algo)
{
case PGP_PUB_ELG_ENCRYPT:
pgp_mpi_free(pk->pub.elg.p);
pgp_mpi_free(pk->pub.elg.g);
pgp_mpi_free(pk->pub.elg.y);
pgp_mpi_free(pk->sec.elg.x);
break;
case PGP_PUB_RSA_SIGN:
case PGP_PUB_RSA_ENCRYPT:
case PGP_PUB_RSA_ENCRYPT_SIGN:
pgp_mpi_free(pk->pub.rsa.n);
pgp_mpi_free(pk->pub.rsa.e);
pgp_mpi_free(pk->sec.rsa.d);
pgp_mpi_free(pk->sec.rsa.p);
pgp_mpi_free(pk->sec.rsa.q);
pgp_mpi_free(pk->sec.rsa.u);
break;
case PGP_PUB_DSA_SIGN:
pgp_mpi_free(pk->pub.dsa.p);
pgp_mpi_free(pk->pub.dsa.q);
pgp_mpi_free(pk->pub.dsa.g);
pgp_mpi_free(pk->pub.dsa.y);
pgp_mpi_free(pk->sec.dsa.x);
break;
}
px_memset(pk, 0, sizeof(*pk));
pfree(pk);
}
static int
calc_key_id(PGP_PubKey *pk)
{
int res;
PX_MD *md;
int len;
uint8 hdr[3];
uint8 hash[20];
res = pgp_load_digest(PGP_DIGEST_SHA1, &md);
if (res < 0)
return res;
len = 1 + 4 + 1;
switch (pk->algo)
{
case PGP_PUB_ELG_ENCRYPT:
len += 2 + pk->pub.elg.p->bytes;
len += 2 + pk->pub.elg.g->bytes;
len += 2 + pk->pub.elg.y->bytes;
break;
case PGP_PUB_RSA_SIGN:
case PGP_PUB_RSA_ENCRYPT:
case PGP_PUB_RSA_ENCRYPT_SIGN:
len += 2 + pk->pub.rsa.n->bytes;
len += 2 + pk->pub.rsa.e->bytes;
break;
case PGP_PUB_DSA_SIGN:
len += 2 + pk->pub.dsa.p->bytes;
len += 2 + pk->pub.dsa.q->bytes;
len += 2 + pk->pub.dsa.g->bytes;
len += 2 + pk->pub.dsa.y->bytes;
break;
}
hdr[0] = 0x99;
hdr[1] = len >> 8;
hdr[2] = len & 0xFF;
px_md_update(md, hdr, 3);
px_md_update(md, &pk->ver, 1);
px_md_update(md, pk->time, 4);
px_md_update(md, &pk->algo, 1);
switch (pk->algo)
{
case PGP_PUB_ELG_ENCRYPT:
pgp_mpi_hash(md, pk->pub.elg.p);
pgp_mpi_hash(md, pk->pub.elg.g);
pgp_mpi_hash(md, pk->pub.elg.y);
break;
case PGP_PUB_RSA_SIGN:
case PGP_PUB_RSA_ENCRYPT:
case PGP_PUB_RSA_ENCRYPT_SIGN:
pgp_mpi_hash(md, pk->pub.rsa.n);
pgp_mpi_hash(md, pk->pub.rsa.e);
break;
case PGP_PUB_DSA_SIGN:
pgp_mpi_hash(md, pk->pub.dsa.p);
pgp_mpi_hash(md, pk->pub.dsa.q);
pgp_mpi_hash(md, pk->pub.dsa.g);
pgp_mpi_hash(md, pk->pub.dsa.y);
break;
}
px_md_finish(md, hash);
px_md_free(md);
memcpy(pk->key_id, hash + 12, 8);
px_memset(hash, 0, 20);
return 0;
}
int
_pgp_read_public_key(PullFilter *pkt, PGP_PubKey **pk_p)
{
int res;
PGP_PubKey *pk;
res = pgp_key_alloc(&pk);
if (res < 0)
return res;
/* get version */
GETBYTE(pkt, pk->ver);
if (pk->ver != 4)
{
res = PXE_PGP_NOT_V4_KEYPKT;
goto out;
}
/* read time */
res = pullf_read_fixed(pkt, 4, pk->time);
if (res < 0)
goto out;
/* pubkey algorithm */
GETBYTE(pkt, pk->algo);
switch (pk->algo)
{
case PGP_PUB_DSA_SIGN:
res = pgp_mpi_read(pkt, &pk->pub.dsa.p);
if (res < 0)
break;
res = pgp_mpi_read(pkt, &pk->pub.dsa.q);
if (res < 0)
break;
res = pgp_mpi_read(pkt, &pk->pub.dsa.g);
if (res < 0)
break;
res = pgp_mpi_read(pkt, &pk->pub.dsa.y);
if (res < 0)
break;
res = calc_key_id(pk);
break;
case PGP_PUB_RSA_SIGN:
case PGP_PUB_RSA_ENCRYPT:
case PGP_PUB_RSA_ENCRYPT_SIGN:
res = pgp_mpi_read(pkt, &pk->pub.rsa.n);
if (res < 0)
break;
res = pgp_mpi_read(pkt, &pk->pub.rsa.e);
if (res < 0)
break;
res = calc_key_id(pk);
if (pk->algo != PGP_PUB_RSA_SIGN)
pk->can_encrypt = 1;
break;
case PGP_PUB_ELG_ENCRYPT:
res = pgp_mpi_read(pkt, &pk->pub.elg.p);
if (res < 0)
break;
res = pgp_mpi_read(pkt, &pk->pub.elg.g);
if (res < 0)
break;
res = pgp_mpi_read(pkt, &pk->pub.elg.y);
if (res < 0)
break;
res = calc_key_id(pk);
pk->can_encrypt = 1;
break;
default:
px_debug("unknown public algo: %d", pk->algo);
res = PXE_PGP_UNKNOWN_PUBALGO;
}
out:
if (res < 0)
pgp_key_free(pk);
else
*pk_p = pk;
return res;
}
#define HIDE_CLEAR 0
#define HIDE_CKSUM 255
#define HIDE_SHA1 254
static int
check_key_sha1(PullFilter *src, PGP_PubKey *pk)
{
int res;
uint8 got_sha1[20];
uint8 my_sha1[20];
PX_MD *md;
res = pullf_read_fixed(src, 20, got_sha1);
if (res < 0)
return res;
res = pgp_load_digest(PGP_DIGEST_SHA1, &md);
if (res < 0)
goto err;
switch (pk->algo)
{
case PGP_PUB_ELG_ENCRYPT:
pgp_mpi_hash(md, pk->sec.elg.x);
break;
case PGP_PUB_RSA_SIGN:
case PGP_PUB_RSA_ENCRYPT:
case PGP_PUB_RSA_ENCRYPT_SIGN:
pgp_mpi_hash(md, pk->sec.rsa.d);
pgp_mpi_hash(md, pk->sec.rsa.p);
pgp_mpi_hash(md, pk->sec.rsa.q);
pgp_mpi_hash(md, pk->sec.rsa.u);
break;
case PGP_PUB_DSA_SIGN:
pgp_mpi_hash(md, pk->sec.dsa.x);
break;
}
px_md_finish(md, my_sha1);
px_md_free(md);
if (memcmp(my_sha1, got_sha1, 20) != 0)
{
px_debug("key sha1 check failed");
res = PXE_PGP_KEYPKT_CORRUPT;
}
err:
px_memset(got_sha1, 0, 20);
px_memset(my_sha1, 0, 20);
return res;
}
static int
check_key_cksum(PullFilter *src, PGP_PubKey *pk)
{
int res;
unsigned got_cksum,
my_cksum = 0;
uint8 buf[2];
res = pullf_read_fixed(src, 2, buf);
if (res < 0)
return res;
got_cksum = ((unsigned) buf[0] << 8) + buf[1];
switch (pk->algo)
{
case PGP_PUB_ELG_ENCRYPT:
my_cksum = pgp_mpi_cksum(0, pk->sec.elg.x);
break;
case PGP_PUB_RSA_SIGN:
case PGP_PUB_RSA_ENCRYPT:
case PGP_PUB_RSA_ENCRYPT_SIGN:
my_cksum = pgp_mpi_cksum(0, pk->sec.rsa.d);
my_cksum = pgp_mpi_cksum(my_cksum, pk->sec.rsa.p);
my_cksum = pgp_mpi_cksum(my_cksum, pk->sec.rsa.q);
my_cksum = pgp_mpi_cksum(my_cksum, pk->sec.rsa.u);
break;
case PGP_PUB_DSA_SIGN:
my_cksum = pgp_mpi_cksum(0, pk->sec.dsa.x);
break;
}
if (my_cksum != got_cksum)
{
px_debug("key cksum check failed");
return PXE_PGP_KEYPKT_CORRUPT;
}
return 0;
}
static int
process_secret_key(PullFilter *pkt, PGP_PubKey **pk_p,
const uint8 *key, int key_len)
{
int res;
int hide_type;
int cipher_algo;
int bs;
uint8 iv[512];
PullFilter *pf_decrypt = NULL,
*pf_key;
PGP_CFB *cfb = NULL;
PGP_S2K s2k;
PGP_PubKey *pk;
/* first read public key part */
res = _pgp_read_public_key(pkt, &pk);
if (res < 0)
return res;
/*
* is secret key encrypted?
*/
GETBYTE(pkt, hide_type);
if (hide_type == HIDE_SHA1 || hide_type == HIDE_CKSUM)
{
if (key == NULL)
return PXE_PGP_NEED_SECRET_PSW;
GETBYTE(pkt, cipher_algo);
res = pgp_s2k_read(pkt, &s2k);
if (res < 0)
return res;
res = pgp_s2k_process(&s2k, cipher_algo, key, key_len);
if (res < 0)
return res;
bs = pgp_get_cipher_block_size(cipher_algo);
if (bs == 0)
{
px_debug("unknown cipher algo=%d", cipher_algo);
return PXE_PGP_UNSUPPORTED_CIPHER;
}
res = pullf_read_fixed(pkt, bs, iv);
if (res < 0)
return res;
/*
* create decrypt filter
*/
res = pgp_cfb_create(&cfb, cipher_algo, s2k.key, s2k.key_len, 0, iv);
if (res < 0)
return res;
res = pullf_create(&pf_decrypt, &pgp_decrypt_filter, cfb, pkt);
if (res < 0)
return res;
pf_key = pf_decrypt;
}
else if (hide_type == HIDE_CLEAR)
{
pf_key = pkt;
}
else
{
px_debug("unknown hide type");
return PXE_PGP_KEYPKT_CORRUPT;
}
/* read secret key */
switch (pk->algo)
{
case PGP_PUB_RSA_SIGN:
case PGP_PUB_RSA_ENCRYPT:
case PGP_PUB_RSA_ENCRYPT_SIGN:
res = pgp_mpi_read(pf_key, &pk->sec.rsa.d);
if (res < 0)
break;
res = pgp_mpi_read(pf_key, &pk->sec.rsa.p);
if (res < 0)
break;
res = pgp_mpi_read(pf_key, &pk->sec.rsa.q);
if (res < 0)
break;
res = pgp_mpi_read(pf_key, &pk->sec.rsa.u);
if (res < 0)
break;
break;
case PGP_PUB_ELG_ENCRYPT:
res = pgp_mpi_read(pf_key, &pk->sec.elg.x);
break;
case PGP_PUB_DSA_SIGN:
res = pgp_mpi_read(pf_key, &pk->sec.dsa.x);
break;
default:
px_debug("unknown public algo: %d", pk->algo);
res = PXE_PGP_KEYPKT_CORRUPT;
}
/* read checksum / sha1 */
if (res >= 0)
{
if (hide_type == HIDE_SHA1)
res = check_key_sha1(pf_key, pk);
else
res = check_key_cksum(pf_key, pk);
}
if (res >= 0)
res = pgp_expect_packet_end(pf_key);
if (pf_decrypt)
pullf_free(pf_decrypt);
if (cfb)
pgp_cfb_free(cfb);
if (res < 0)
pgp_key_free(pk);
else
*pk_p = pk;
return res;
}
static int
internal_read_key(PullFilter *src, PGP_PubKey **pk_p,
const uint8 *psw, int psw_len, int pubtype)
{
PullFilter *pkt = NULL;
int res;
uint8 tag;
int len;
PGP_PubKey *enc_key = NULL;
PGP_PubKey *pk = NULL;
int got_main_key = 0;
/*
* Search for encryption key.
*
* Error out on anything fancy.
*/
while (1)
{
res = pgp_parse_pkt_hdr(src, &tag, &len, 0);
if (res <= 0)
break;
res = pgp_create_pkt_reader(&pkt, src, len, res, NULL);
if (res < 0)
break;
switch (tag)
{
case PGP_PKT_PUBLIC_KEY:
case PGP_PKT_SECRET_KEY:
if (got_main_key)
{
res = PXE_PGP_MULTIPLE_KEYS;
break;
}
got_main_key = 1;
res = pgp_skip_packet(pkt);
break;
case PGP_PKT_PUBLIC_SUBKEY:
if (pubtype != 0)
res = PXE_PGP_EXPECT_SECRET_KEY;
else
res = _pgp_read_public_key(pkt, &pk);
break;
case PGP_PKT_SECRET_SUBKEY:
if (pubtype != 1)
res = PXE_PGP_EXPECT_PUBLIC_KEY;
else
res = process_secret_key(pkt, &pk, psw, psw_len);
break;
case PGP_PKT_SIGNATURE:
case PGP_PKT_MARKER:
case PGP_PKT_TRUST:
case PGP_PKT_USER_ID:
case PGP_PKT_USER_ATTR:
case PGP_PKT_PRIV_61:
res = pgp_skip_packet(pkt);
break;
default:
px_debug("unknown/unexpected packet: %d", tag);
res = PXE_PGP_UNEXPECTED_PKT;
}
pullf_free(pkt);
pkt = NULL;
if (pk != NULL)
{
if (res >= 0 && pk->can_encrypt)
{
if (enc_key == NULL)
{
enc_key = pk;
pk = NULL;
}
else
res = PXE_PGP_MULTIPLE_SUBKEYS;
}
if (pk)
pgp_key_free(pk);
pk = NULL;
}
if (res < 0)
break;
}
if (pkt)
pullf_free(pkt);
if (res < 0)
{
if (enc_key)
pgp_key_free(enc_key);
return res;
}
if (!enc_key)
res = PXE_PGP_NO_USABLE_KEY;
else
*pk_p = enc_key;
return res;
}
int
pgp_set_pubkey(PGP_Context *ctx, MBuf *keypkt,
const uint8 *key, int key_len, int pubtype)
{
int res;
PullFilter *src;
PGP_PubKey *pk = NULL;
res = pullf_create_mbuf_reader(&src, keypkt);
if (res < 0)
return res;
res = internal_read_key(src, &pk, key, key_len, pubtype);
pullf_free(src);
if (res >= 0)
ctx->pub_key = pk;
return res < 0 ? res : 0;
}
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