static int
decrypt_elgamal(PGP_PubKey *pk, PullFilter *pkt, PGP_MPI **m_p)
{
int res;
PGP_MPI *c1 = NULL;
PGP_MPI *c2 = NULL;
if (pk->algo != PGP_PUB_ELG_ENCRYPT)
return PXE_PGP_WRONG_KEY;
/* read elgamal encrypted data */
res = pgp_mpi_read(pkt, &c1);
if (res < 0)
goto out;
res = pgp_mpi_read(pkt, &c2);
if (res < 0)
goto out;
/* decrypt */
res = pgp_elgamal_decrypt(pk, c1, c2, m_p);
out:
pgp_mpi_free(c1);
pgp_mpi_free(c2);
return res;
}
static int
decrypt_rsa(PGP_PubKey *pk, PullFilter *pkt, PGP_MPI **m_p)
{
int res;
PGP_MPI *c;
if (pk->algo != PGP_PUB_RSA_ENCRYPT
&& pk->algo != PGP_PUB_RSA_ENCRYPT_SIGN)
return PXE_PGP_WRONG_KEY;
/* read rsa encrypted data */
res = pgp_mpi_read(pkt, &c);
if (res < 0)
return res;
/* decrypt */
res = pgp_rsa_decrypt(pk, c, m_p);
pgp_mpi_free(c);
return res;
}
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(pkt, &pk->sec.rsa.d);
if (res < 0)
break;
res = pgp_mpi_read(pkt, &pk->sec.rsa.p);
if (res < 0)
break;
res = pgp_mpi_read(pkt, &pk->sec.rsa.q);
if (res < 0)
break;
res = pgp_mpi_read(pkt, &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;
}
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;
}
