pgp-pubdec.c File Reference

#include "postgres.h"
#include "px.h"
#include "mbuf.h"
#include "pgp.h"

Include dependency graph for pgp-pubdec.c:

Go to the source code of this file.

Functions
static uint8 *	check_eme_pkcs1_v15 (uint8 *data, int len)
static int	control_cksum (uint8 *msg, int msglen)
static int	decrypt_elgamal (PGP_PubKey *pk, PullFilter *pkt, PGP_MPI **m_p)
static int	decrypt_rsa (PGP_PubKey *pk, PullFilter *pkt, PGP_MPI **m_p)
int	pgp_parse_pubenc_sesskey (PGP_Context *ctx, PullFilter *pkt)
Variables
static const uint8	any_key [] = {0, 0, 0, 0, 0, 0, 0, 0}

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Function Documentation

static uint8* check_eme_pkcs1_v15	(	uint8 *	data,
		int	len
	)			[static]

Definition at line 43 of file pgp-pubdec.c.

Referenced by pgp_parse_pubenc_sesskey().

{
    uint8      *data_end = data + len;
    uint8      *p = data;
    int         rnd = 0;

    if (len < 1 + 8 + 1)
        return NULL;

    if (*p++ != 2)
        return NULL;

    while (p < data_end && *p)
    {
        p++;
        rnd++;
    }

    if (p == data_end)
        return NULL;
    if (*p != 0)
        return NULL;
    if (rnd < 8)
        return NULL;
    return p + 1;
}

static int control_cksum	(	uint8 *	msg,
		int	msglen
	)			[static]

Definition at line 75 of file pgp-pubdec.c.

References i, and px_debug().

Referenced by pgp_parse_pubenc_sesskey().

{
    int         i;
    unsigned    my_cksum,
                got_cksum;

    if (msglen < 3)
        return PXE_PGP_WRONG_KEY;

    my_cksum = 0;
    for (i = 1; i < msglen - 2; i++)
        my_cksum += msg[i];
    my_cksum &= 0xFFFF;
    got_cksum = ((unsigned) (msg[msglen - 2]) << 8) + msg[msglen - 1];
    if (my_cksum != got_cksum)
    {
        px_debug("pubenc cksum failed");
        return PXE_PGP_WRONG_KEY;
    }
    return 0;
}

static int decrypt_elgamal	(	PGP_PubKey *	pk,
		PullFilter *	pkt,
		PGP_MPI **	m_p
	)			[static]

Definition at line 98 of file pgp-pubdec.c.

References PGP_PubKey::algo, pgp_elgamal_decrypt(), pgp_mpi_free(), pgp_mpi_read(), and PGP_PUB_ELG_ENCRYPT.

Referenced by pgp_parse_pubenc_sesskey().

{
    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
	)			[static]

Definition at line 125 of file pgp-pubdec.c.

References PGP_PubKey::algo, pgp_mpi_free(), pgp_mpi_read(), PGP_PUB_RSA_ENCRYPT, PGP_PUB_RSA_ENCRYPT_SIGN, and pgp_rsa_decrypt().

Referenced by pgp_parse_pubenc_sesskey().

{
    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;
}

int pgp_parse_pubenc_sesskey	(	PGP_Context *	ctx,
		PullFilter *	pkt
	)

Definition at line 151 of file pgp-pubdec.c.

References any_key, PGP_MPI::bytes, check_eme_pkcs1_v15(), PGP_Context::cipher_algo, control_cksum(), PGP_MPI::data, decrypt_elgamal(), decrypt_rsa(), GETBYTE, PGP_PubKey::key_id, memcmp(), NULL, pgp_expect_packet_end(), pgp_mpi_free(), PGP_PUB_ELG_ENCRYPT, PGP_PUB_RSA_ENCRYPT, PGP_PUB_RSA_ENCRYPT_SIGN, PGP_Context::pub_key, pullf_read_fixed(), px_debug(), PGP_Context::sess_key, and PGP_Context::sess_key_len.

Referenced by pgp_decrypt().

{
    int         ver;
    int         algo;
    int         res;
    uint8       key_id[8];
    PGP_PubKey *pk;
    uint8      *msg;
    int         msglen;
    PGP_MPI    *m;

    pk = ctx->pub_key;
    if (pk == NULL)
    {
        px_debug("no pubkey?");
        return PXE_BUG;
    }

    GETBYTE(pkt, ver);
    if (ver != 3)
    {
        px_debug("unknown pubenc_sesskey pkt ver=%d", ver);
        return PXE_PGP_CORRUPT_DATA;
    }

    /*
     * check if keyid's match - user-friendly msg
     */
    res = pullf_read_fixed(pkt, 8, key_id);
    if (res < 0)
        return res;
    if (memcmp(key_id, any_key, 8) != 0
        && memcmp(key_id, pk->key_id, 8) != 0)
    {
        px_debug("key_id's does not match");
        return PXE_PGP_WRONG_KEY;
    }

    /*
     * Decrypt
     */
    GETBYTE(pkt, algo);
    switch (algo)
    {
        case PGP_PUB_ELG_ENCRYPT:
            res = decrypt_elgamal(pk, pkt, &m);
            break;
        case PGP_PUB_RSA_ENCRYPT:
        case PGP_PUB_RSA_ENCRYPT_SIGN:
            res = decrypt_rsa(pk, pkt, &m);
            break;
        default:
            res = PXE_PGP_UNKNOWN_PUBALGO;
    }
    if (res < 0)
        return res;

    /*
     * extract message
     */
    msg = check_eme_pkcs1_v15(m->data, m->bytes);
    if (msg == NULL)
    {
        px_debug("check_eme_pkcs1_v15 failed");
        res = PXE_PGP_WRONG_KEY;
        goto out;
    }
    msglen = m->bytes - (msg - m->data);

    res = control_cksum(msg, msglen);
    if (res < 0)
        goto out;

    /*
     * got sesskey
     */
    ctx->cipher_algo = *msg;
    ctx->sess_key_len = msglen - 3;
    memcpy(ctx->sess_key, msg + 1, ctx->sess_key_len);

out:
    pgp_mpi_free(m);
    if (res < 0)
        return res;
    return pgp_expect_packet_end(pkt);
}

---

Variable Documentation

const uint8 any_key[] = {0, 0, 0, 0, 0, 0, 0, 0} [static]

Definition at line 148 of file pgp-pubdec.c.

Referenced by pgp_parse_pubenc_sesskey().