postgresql/contrib/pgcrypto/pgp-encrypt.c
2010-09-20 22:08:53 +02:00

709 lines
12 KiB
C

/*
* pgp-encrypt.c
* OpenPGP encrypt.
*
* 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-encrypt.c
*/
#include "postgres.h"
#include <time.h>
#include "mbuf.h"
#include "px.h"
#include "pgp.h"
#define MDC_DIGEST_LEN 20
#define STREAM_ID 0xE0
#define STREAM_BLOCK_SHIFT 14
static uint8 *
render_newlen(uint8 *h, int len)
{
if (len <= 191)
{
*h++ = len & 255;
}
else if (len > 191 && len <= 8383)
{
*h++ = ((len - 192) >> 8) + 192;
*h++ = (len - 192) & 255;
}
else
{
*h++ = 255;
*h++ = (len >> 24) & 255;
*h++ = (len >> 16) & 255;
*h++ = (len >> 8) & 255;
*h++ = len & 255;
}
return h;
}
static int
write_tag_only(PushFilter *dst, int tag)
{
uint8 hdr = 0xC0 | tag;
return pushf_write(dst, &hdr, 1);
}
static int
write_normal_header(PushFilter *dst, int tag, int len)
{
uint8 hdr[8];
uint8 *h = hdr;
*h++ = 0xC0 | tag;
h = render_newlen(h, len);
return pushf_write(dst, hdr, h - hdr);
}
/*
* MAC writer
*/
static int
mdc_init(PushFilter *dst, void *init_arg, void **priv_p)
{
int res;
PX_MD *md;
res = pgp_load_digest(PGP_DIGEST_SHA1, &md);
if (res < 0)
return res;
*priv_p = md;
return 0;
}
static int
mdc_write(PushFilter *dst, void *priv, const uint8 *data, int len)
{
PX_MD *md = priv;
px_md_update(md, data, len);
return pushf_write(dst, data, len);
}
static int
mdc_flush(PushFilter *dst, void *priv)
{
int res;
uint8 pkt[2 + MDC_DIGEST_LEN];
PX_MD *md = priv;
/*
* create mdc pkt
*/
pkt[0] = 0xD3;
pkt[1] = 0x14; /* MDC_DIGEST_LEN */
px_md_update(md, pkt, 2);
px_md_finish(md, pkt + 2);
res = pushf_write(dst, pkt, 2 + MDC_DIGEST_LEN);
memset(pkt, 0, 2 + MDC_DIGEST_LEN);
return res;
}
static void
mdc_free(void *priv)
{
PX_MD *md = priv;
px_md_free(md);
}
static const PushFilterOps mdc_filter = {
mdc_init, mdc_write, mdc_flush, mdc_free
};
/*
* Encrypted pkt writer
*/
#define ENCBUF 8192
struct EncStat
{
PGP_CFB *ciph;
uint8 buf[ENCBUF];
};
static int
encrypt_init(PushFilter *next, void *init_arg, void **priv_p)
{
struct EncStat *st;
PGP_Context *ctx = init_arg;
PGP_CFB *ciph;
int resync = 1;
int res;
/* should we use newer packet format? */
if (ctx->disable_mdc == 0)
{
uint8 ver = 1;
resync = 0;
res = pushf_write(next, &ver, 1);
if (res < 0)
return res;
}
res = pgp_cfb_create(&ciph, ctx->cipher_algo,
ctx->sess_key, ctx->sess_key_len, resync, NULL);
if (res < 0)
return res;
st = px_alloc(sizeof(*st));
memset(st, 0, sizeof(*st));
st->ciph = ciph;
*priv_p = st;
return ENCBUF;
}
static int
encrypt_process(PushFilter *next, void *priv, const uint8 *data, int len)
{
int res;
struct EncStat *st = priv;
int avail = len;
while (avail > 0)
{
int tmplen = avail > ENCBUF ? ENCBUF : avail;
res = pgp_cfb_encrypt(st->ciph, data, tmplen, st->buf);
if (res < 0)
return res;
res = pushf_write(next, st->buf, tmplen);
if (res < 0)
return res;
data += tmplen;
avail -= tmplen;
}
return 0;
}
static void
encrypt_free(void *priv)
{
struct EncStat *st = priv;
memset(st, 0, sizeof(*st));
px_free(st);
}
static const PushFilterOps encrypt_filter = {
encrypt_init, encrypt_process, NULL, encrypt_free
};
/*
* Write Streamable pkts
*/
struct PktStreamStat
{
int final_done;
int pkt_block;
};
static int
pkt_stream_init(PushFilter *next, void *init_arg, void **priv_p)
{
struct PktStreamStat *st;
st = px_alloc(sizeof(*st));
st->final_done = 0;
st->pkt_block = 1 << STREAM_BLOCK_SHIFT;
*priv_p = st;
return st->pkt_block;
}
static int
pkt_stream_process(PushFilter *next, void *priv, const uint8 *data, int len)
{
int res;
uint8 hdr[8];
uint8 *h = hdr;
struct PktStreamStat *st = priv;
if (st->final_done)
return PXE_BUG;
if (len == st->pkt_block)
*h++ = STREAM_ID | STREAM_BLOCK_SHIFT;
else
{
h = render_newlen(h, len);
st->final_done = 1;
}
res = pushf_write(next, hdr, h - hdr);
if (res < 0)
return res;
return pushf_write(next, data, len);
}
static int
pkt_stream_flush(PushFilter *next, void *priv)
{
int res;
uint8 hdr[8];
uint8 *h = hdr;
struct PktStreamStat *st = priv;
/* stream MUST end with normal packet. */
if (!st->final_done)
{
h = render_newlen(h, 0);
res = pushf_write(next, hdr, h - hdr);
if (res < 0)
return res;
st->final_done = 1;
}
return 0;
}
static void
pkt_stream_free(void *priv)
{
struct PktStreamStat *st = priv;
memset(st, 0, sizeof(*st));
px_free(st);
}
static const PushFilterOps pkt_stream_filter = {
pkt_stream_init, pkt_stream_process, pkt_stream_flush, pkt_stream_free
};
int
pgp_create_pkt_writer(PushFilter *dst, int tag, PushFilter **res_p)
{
int res;
res = write_tag_only(dst, tag);
if (res < 0)
return res;
return pushf_create(res_p, &pkt_stream_filter, NULL, dst);
}
/*
* Text conversion filter
*/
static int
crlf_process(PushFilter *dst, void *priv, const uint8 *data, int len)
{
const uint8 *data_end = data + len;
const uint8 *p2,
*p1 = data;
int line_len;
static const uint8 crlf[] = {'\r', '\n'};
int res = 0;
while (p1 < data_end)
{
p2 = memchr(p1, '\n', data_end - p1);
if (p2 == NULL)
p2 = data_end;
line_len = p2 - p1;
/* write data */
res = 0;
if (line_len > 0)
{
res = pushf_write(dst, p1, line_len);
if (res < 0)
break;
p1 += line_len;
}
/* write crlf */
while (p1 < data_end && *p1 == '\n')
{
res = pushf_write(dst, crlf, 2);
if (res < 0)
break;
p1++;
}
}
return res;
}
static const PushFilterOps crlf_filter = {
NULL, crlf_process, NULL, NULL
};
/*
* Initialize literal data packet
*/
static int
init_litdata_packet(PushFilter **pf_res, PGP_Context *ctx, PushFilter *dst)
{
int res;
int hdrlen;
uint8 hdr[6];
uint32 t;
PushFilter *pkt;
int type;
/*
* Create header
*/
if (ctx->text_mode)
type = ctx->unicode_mode ? 'u' : 't';
else
type = 'b';
/*
* Store the creation time into packet. The goal is to have as few known
* bytes as possible.
*/
t = (uint32) time(NULL);
hdr[0] = type;
hdr[1] = 0;
hdr[2] = (t >> 24) & 255;
hdr[3] = (t >> 16) & 255;
hdr[4] = (t >> 8) & 255;
hdr[5] = t & 255;
hdrlen = 6;
res = write_tag_only(dst, PGP_PKT_LITERAL_DATA);
if (res < 0)
return res;
res = pushf_create(&pkt, &pkt_stream_filter, ctx, dst);
if (res < 0)
return res;
res = pushf_write(pkt, hdr, hdrlen);
if (res < 0)
{
pushf_free(pkt);
return res;
}
*pf_res = pkt;
return 0;
}
/*
* Initialize compression filter
*/
static int
init_compress(PushFilter **pf_res, PGP_Context *ctx, PushFilter *dst)
{
int res;
uint8 type = ctx->compress_algo;
PushFilter *pkt;
res = write_tag_only(dst, PGP_PKT_COMPRESSED_DATA);
if (res < 0)
return res;
res = pushf_create(&pkt, &pkt_stream_filter, ctx, dst);
if (res < 0)
return res;
res = pushf_write(pkt, &type, 1);
if (res >= 0)
res = pgp_compress_filter(pf_res, ctx, pkt);
if (res < 0)
pushf_free(pkt);
return res;
}
/*
* Initialize encdata packet
*/
static int
init_encdata_packet(PushFilter **pf_res, PGP_Context *ctx, PushFilter *dst)
{
int res;
int tag;
if (ctx->disable_mdc)
tag = PGP_PKT_SYMENCRYPTED_DATA;
else
tag = PGP_PKT_SYMENCRYPTED_DATA_MDC;
res = write_tag_only(dst, tag);
if (res < 0)
return res;
return pushf_create(pf_res, &pkt_stream_filter, ctx, dst);
}
/*
* write prefix
*/
static int
write_prefix(PGP_Context *ctx, PushFilter *dst)
{
uint8 prefix[PGP_MAX_BLOCK + 2];
int res,
bs;
bs = pgp_get_cipher_block_size(ctx->cipher_algo);
res = px_get_random_bytes(prefix, bs);
if (res < 0)
return res;
prefix[bs + 0] = prefix[bs - 2];
prefix[bs + 1] = prefix[bs - 1];
res = pushf_write(dst, prefix, bs + 2);
memset(prefix, 0, bs + 2);
return res < 0 ? res : 0;
}
/*
* write symmetrically encrypted session key packet
*/
static int
symencrypt_sesskey(PGP_Context *ctx, uint8 *dst)
{
int res;
PGP_CFB *cfb;
uint8 algo = ctx->cipher_algo;
res = pgp_cfb_create(&cfb, ctx->s2k_cipher_algo,
ctx->s2k.key, ctx->s2k.key_len, 0, NULL);
if (res < 0)
return res;
pgp_cfb_encrypt(cfb, &algo, 1, dst);
pgp_cfb_encrypt(cfb, ctx->sess_key, ctx->sess_key_len, dst + 1);
pgp_cfb_free(cfb);
return ctx->sess_key_len + 1;
}
/* 5.3: Symmetric-Key Encrypted Session-Key */
static int
write_symenc_sesskey(PGP_Context *ctx, PushFilter *dst)
{
uint8 pkt[256];
int pktlen;
int res;
uint8 *p = pkt;
*p++ = 4; /* 5.3 - version number */
*p++ = ctx->s2k_cipher_algo;
*p++ = ctx->s2k.mode;
*p++ = ctx->s2k.digest_algo;
if (ctx->s2k.mode > 0)
{
memcpy(p, ctx->s2k.salt, 8);
p += 8;
}
if (ctx->s2k.mode == 3)
*p++ = ctx->s2k.iter;
if (ctx->use_sess_key)
{
res = symencrypt_sesskey(ctx, p);
if (res < 0)
return res;
p += res;
}
pktlen = p - pkt;
res = write_normal_header(dst, PGP_PKT_SYMENCRYPTED_SESSKEY, pktlen);
if (res >= 0)
res = pushf_write(dst, pkt, pktlen);
memset(pkt, 0, pktlen);
return res;
}
/*
* key setup
*/
static int
init_s2k_key(PGP_Context *ctx)
{
int res;
if (ctx->s2k_cipher_algo < 0)
ctx->s2k_cipher_algo = ctx->cipher_algo;
res = pgp_s2k_fill(&ctx->s2k, ctx->s2k_mode, ctx->s2k_digest_algo);
if (res < 0)
return res;
return pgp_s2k_process(&ctx->s2k, ctx->s2k_cipher_algo,
ctx->sym_key, ctx->sym_key_len);
}
static int
init_sess_key(PGP_Context *ctx)
{
int res;
if (ctx->use_sess_key || ctx->pub_key)
{
ctx->sess_key_len = pgp_get_cipher_key_size(ctx->cipher_algo);
res = px_get_random_bytes(ctx->sess_key, ctx->sess_key_len);
if (res < 0)
return res;
}
else
{
ctx->sess_key_len = ctx->s2k.key_len;
memcpy(ctx->sess_key, ctx->s2k.key, ctx->s2k.key_len);
}
return 0;
}
/*
* combine
*/
int
pgp_encrypt(PGP_Context *ctx, MBuf *src, MBuf *dst)
{
int res;
int len;
uint8 *buf;
PushFilter *pf,
*pf_tmp;
/*
* do we have any key
*/
if (!ctx->sym_key && !ctx->pub_key)
return PXE_ARGUMENT_ERROR;
/* MBuf writer */
res = pushf_create_mbuf_writer(&pf, dst);
if (res < 0)
goto out;
/*
* initialize symkey
*/
if (ctx->sym_key)
{
res = init_s2k_key(ctx);
if (res < 0)
goto out;
}
res = init_sess_key(ctx);
if (res < 0)
goto out;
/*
* write keypkt
*/
if (ctx->pub_key)
res = pgp_write_pubenc_sesskey(ctx, pf);
else
res = write_symenc_sesskey(ctx, pf);
if (res < 0)
goto out;
/* encrypted data pkt */
res = init_encdata_packet(&pf_tmp, ctx, pf);
if (res < 0)
goto out;
pf = pf_tmp;
/* encrypter */
res = pushf_create(&pf_tmp, &encrypt_filter, ctx, pf);
if (res < 0)
goto out;
pf = pf_tmp;
/* hasher */
if (ctx->disable_mdc == 0)
{
res = pushf_create(&pf_tmp, &mdc_filter, ctx, pf);
if (res < 0)
goto out;
pf = pf_tmp;
}
/* prefix */
res = write_prefix(ctx, pf);
if (res < 0)
goto out;
/* compressor */
if (ctx->compress_algo > 0 && ctx->compress_level > 0)
{
res = init_compress(&pf_tmp, ctx, pf);
if (res < 0)
goto out;
pf = pf_tmp;
}
/* data streamer */
res = init_litdata_packet(&pf_tmp, ctx, pf);
if (res < 0)
goto out;
pf = pf_tmp;
/* text conversion? */
if (ctx->text_mode && ctx->convert_crlf)
{
res = pushf_create(&pf_tmp, &crlf_filter, ctx, pf);
if (res < 0)
goto out;
pf = pf_tmp;
}
/*
* chain complete
*/
len = mbuf_grab(src, mbuf_avail(src), &buf);
res = pushf_write(pf, buf, len);
if (res >= 0)
res = pushf_flush(pf);
out:
pushf_free_all(pf);
return res;
}