diff options
Diffstat (limited to 'contrib/pgcrypto/pgp-pubenc.c')
| -rw-r--r-- | contrib/pgcrypto/pgp-pubenc.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/contrib/pgcrypto/pgp-pubenc.c b/contrib/pgcrypto/pgp-pubenc.c new file mode 100644 index 0000000000..7a0ba33409 --- /dev/null +++ b/contrib/pgcrypto/pgp-pubenc.c @@ -0,0 +1,230 @@ +/* + * pgp-pubenc.c + * Encrypt session key with public 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. + * + * $PostgreSQL: pgsql/contrib/pgcrypto/pgp-pubenc.c,v 1.1 2005/07/10 13:46:29 momjian Exp $ + */ +#include <postgres.h> + +#include "px.h" +#include "mbuf.h" +#include "pgp.h" + +/* + * padded msg: 02 || non-zero pad bytes || 00 || msg + */ +static int +pad_eme_pkcs1_v15(uint8 *data, int data_len, int res_len, uint8 **res_p) +{ + int res; + uint8 *buf, *p; + int pad_len = res_len - 2 - data_len; + + if (pad_len < 8) + return PXE_BUG; + + buf = px_alloc(res_len); + buf[0] = 0x02; + res = px_get_random_bytes(buf + 1, pad_len); + if (res < 0) + { + px_free(buf); + return res; + } + + /* pad must not contain zero bytes */ + p = buf + 1; + while (p < buf + 1 + pad_len) + { + if (*p == 0) + { + res = px_get_random_bytes(p, 1); + if (res < 0) + break; + } + if (*p != 0) + p++; + } + + if (res < 0) + { + memset(buf, 0, res_len); + px_free(buf); + return res; + } + + buf[pad_len + 1] = 0; + memcpy(buf + pad_len + 2, data, data_len); + *res_p = buf; + + return 0; +} + +/* + * Decide the padded message length in bytes. + * It should be as large as possible, but not larger + * than p. + * + * To get max size (and assuming p may have weird sizes): + * ((p->bytes * 8 - 6) > p->bits) ? (p->bytes - 1) : p->bytes + * + * Following mirrors gnupg behaviour. + */ +static int +decide_msglen(PGP_MPI *p) +{ + return p->bytes - 1; +} + +static int +create_secmsg(PGP_Context *ctx, PGP_MPI **msg_p) +{ + uint8 *secmsg; + int res, i, full_bytes; + unsigned cksum = 0; + int klen = ctx->sess_key_len; + uint8 *padded = NULL; + PGP_MPI *m = NULL; + PGP_PubKey *pk = ctx->pub_key; + + /* + * Refuse to operate with keys < 1024 + */ + if (pk->elg_p->bits < 1024) + return PXE_PGP_SHORT_ELGAMAL_KEY; + + /* calc checksum */ + for (i = 0; i < klen; i++) + cksum += ctx->sess_key[i]; + + /* + * create "secret message" + */ + secmsg = px_alloc(klen + 3); + secmsg[0] = ctx->cipher_algo; + memcpy(secmsg + 1, ctx->sess_key, klen); + secmsg[klen + 1] = (cksum >> 8) & 0xFF; + secmsg[klen + 2] = cksum & 0xFF; + + /* + * now create a large integer of it + */ + full_bytes = decide_msglen(pk->elg_p); + res = pad_eme_pkcs1_v15(secmsg, klen + 3, full_bytes, &padded); + if (res >= 0) + { + /* first byte will be 0x02 */ + int full_bits = full_bytes * 8 - 6; + res = pgp_mpi_create(padded, full_bits, &m); + } + + if (padded) + { + memset(padded, 0, full_bytes); + px_free(padded); + } + memset(secmsg, 0, klen + 3); + px_free(secmsg); + + if (res >= 0) + *msg_p = m; + + return res; +} + +int pgp_write_pubenc_sesskey(PGP_Context *ctx, PushFilter *dst) +{ + int res; + PGP_PubKey *pk = ctx->pub_key; + PGP_MPI *m = NULL, *c1 = NULL, *c2 = NULL; + uint8 ver = 3; + uint8 algo = PGP_PUB_ELG_ENCRYPT; + PushFilter *pkt = NULL; + + if (pk == NULL) { + px_debug("no pubkey?\n"); + return PXE_BUG; + } + if (!pk->elg_p || !pk->elg_g || !pk->elg_y) { + px_debug("pubkey not loaded?\n"); + return PXE_BUG; + } + + /* + * sesskey packet + */ + res = create_secmsg(ctx, &m); + if (res < 0) + goto err; + + /* + * encrypt it + */ + res = pgp_elgamal_encrypt(pk, m, &c1, &c2); + if (res < 0) + goto err; + + /* + * now write packet + */ + res = pgp_create_pkt_writer(dst, PGP_PKT_PUBENCRYPTED_SESSKEY, &pkt); + if (res < 0) + goto err; + res = pushf_write(pkt, &ver, 1); + if (res < 0) + goto err; + res = pushf_write(pkt, pk->key_id, 8); + if (res < 0) + goto err; + res = pushf_write(pkt, &algo, 1); + if (res < 0) + goto err; + res = pgp_mpi_write(pkt, c1); + if (res < 0) + goto err; + res = pgp_mpi_write(pkt, c2); + if (res < 0) + goto err; + + /* + * done, signal packet end + */ + res = pushf_flush(pkt); +err: + if (pkt) + pushf_free(pkt); + if (m) + pgp_mpi_free(m); + if (c1) + pgp_mpi_free(c1); + if (c2) + pgp_mpi_free(c2); + + return res; +} + + |