/* vim: set tabstop=8 shiftwidth=4 softtabstop=4 expandtab smarttab colorcolumn=80: */
/*
 * Copyright 2016 Red Hat, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "misc.h"
#include <jose/b64.h>
#include "../hooks.h"
#include <jose/openssl.h>

#include <openssl/rand.h>
#include <openssl/objects.h>

#include <string.h>

declare_cleanup(EC_POINT)
declare_cleanup(EC_KEY)
declare_cleanup(BN_CTX)
declare_cleanup(RSA)

static EC_POINT *
mkpub(const EC_GROUP *grp, const json_t *x, const json_t *y, const BIGNUM *D)
{
    openssl_auto(EC_POINT) *pub = NULL;
    openssl_auto(BN_CTX) *cfg = NULL;
    openssl_auto(BIGNUM) *X = NULL;
    openssl_auto(BIGNUM) *Y = NULL;

    cfg = BN_CTX_new();
    if (!cfg)
        return NULL;

    pub = EC_POINT_new(grp);
    if (!pub)
        return NULL;

    if (x && y) {
        X = bn_decode_json(x);
        Y = bn_decode_json(y);
        if (!X || !Y)
            return NULL;

        if (EC_POINT_set_affine_coordinates_GFp(grp, pub, X, Y, cfg) < 0)
            return NULL;
    } else if (D) {
        if (EC_POINT_mul(grp, pub, D, NULL, NULL, cfg) < 0)
            return NULL;
    } else {
        return NULL;
    }

    return EC_POINT_dup(pub, grp);
}

json_t *
jose_openssl_jwk_from_EVP_PKEY(jose_cfg_t *cfg, EVP_PKEY *key)
{
    const uint8_t *buf = NULL;
    size_t len = 0;

    switch (EVP_PKEY_base_id(key)) {
    case EVP_PKEY_HMAC:
        buf = EVP_PKEY_get0_hmac(key, &len);
        if (!buf)
            return NULL;

        return json_pack("{s:s,s:o}", "kty", "oct", "k",
                         jose_b64_enc(buf, len));

    case EVP_PKEY_RSA:
        return jose_openssl_jwk_from_RSA(cfg, EVP_PKEY_get0_RSA(key));

    case EVP_PKEY_EC:
        return jose_openssl_jwk_from_EC_KEY(cfg, EVP_PKEY_get0_EC_KEY(key));
    default: return NULL;
    }
}

json_t *
jose_openssl_jwk_from_RSA(jose_cfg_t *cfg, const RSA *key)
{
    const BIGNUM *n = NULL;
    const BIGNUM *e = NULL;
    const BIGNUM *d = NULL;
    const BIGNUM *p = NULL;
    const BIGNUM *q = NULL;
    const BIGNUM *dp = NULL;
    const BIGNUM *dq = NULL;
    const BIGNUM *qi = NULL;
    json_auto_t *jwk = NULL;

    if (!key)
        return NULL;

    RSA_get0_key(key, &n, &e, &d);
    RSA_get0_factors(key, &p, &q);
    RSA_get0_crt_params(key, &dp, &dq, &qi);

    if (!n || !e)
        return NULL;

    jwk = json_pack("{s:s,s:o,s:o}",
                    "kty", "RSA",
                    "n", bn_encode_json(n, 0),
                    "e", bn_encode_json(e, 0));

    if (d && json_object_set_new(jwk, "d", bn_encode_json(d, 0)) != 0)
        return NULL;

    if (p && json_object_set_new(jwk, "p", bn_encode_json(p, 0)) != 0)
        return NULL;

    if (q && json_object_set_new(jwk, "q", bn_encode_json(q, 0)) != 0)
        return NULL;

    if (dp && json_object_set_new(jwk, "dp", bn_encode_json(dp, 0)) != 0)
        return NULL;

    if (dq && json_object_set_new(jwk, "dq", bn_encode_json(dq, 0)) != 0)
        return NULL;

    if (qi && json_object_set_new(jwk, "qi", bn_encode_json(qi, 0)) != 0)
        return NULL;

    return json_incref(jwk);
}

json_t *
jose_openssl_jwk_from_EC_KEY(jose_cfg_t *cfg, const EC_KEY *key)
{
    return jose_openssl_jwk_from_EC_POINT(
        cfg,
        EC_KEY_get0_group(key),
        EC_KEY_get0_public_key(key),
        EC_KEY_get0_private_key(key)
    );
}

json_t *
jose_openssl_jwk_from_EC_POINT(jose_cfg_t *cfg, const EC_GROUP *grp,
                               const EC_POINT *pub, const BIGNUM *prv)
{
    openssl_auto(EC_POINT) *p = NULL;
    openssl_auto(BN_CTX) *ctx = NULL;
    openssl_auto(BIGNUM) *x = NULL;
    openssl_auto(BIGNUM) *y = NULL;
    json_auto_t *jwk = NULL;
    const char *crv = NULL;
    int len = 0;

    if (!grp)
        return NULL;

    len = (EC_GROUP_get_degree(grp) + 7) / 8;

    switch (EC_GROUP_get_curve_name(grp)) {
    case NID_X9_62_prime256v1: crv = "P-256"; break;
    case NID_secp384r1: crv = "P-384"; break;
    case NID_secp521r1: crv = "P-521"; break;
    default: return NULL;
    }

    ctx = BN_CTX_new();
    if (!ctx)
        return NULL;

    if (!pub) {
        if (!prv)
            return NULL;

        pub = p = EC_POINT_new(grp);
        if (!pub)
            return NULL;

        if (EC_POINT_mul(grp, p, prv, NULL, NULL, ctx) < 0)
            return NULL;
    }

    x = BN_new();
    y = BN_new();
    if (!x || !y)
        return NULL;

    if (EC_POINT_get_affine_coordinates_GFp(grp, pub, x, y, ctx) < 0)
        return NULL;

    jwk = json_pack("{s:s,s:s,s:o,s:o}", "kty", "EC", "crv", crv,
                    "x", bn_encode_json(x, len), "y", bn_encode_json(y, len));
    if (prv && json_object_set_new(jwk, "d", bn_encode_json(prv, len)) == -1)
        return NULL;

    return json_incref(jwk);
}

EVP_PKEY *
jose_openssl_jwk_to_EVP_PKEY(jose_cfg_t *cfg, const json_t *jwk)
{
    openssl_auto(EC_KEY) *ec = NULL;
    openssl_auto(RSA) *rsa = NULL;
    const char *kty = NULL;
    EVP_PKEY *key = NULL;
    uint8_t *buf = NULL;
    size_t len = 0;

    if (json_unpack((json_t *) jwk, "{s:s}", "kty", &kty) == -1)
        return NULL;

    switch (str2enum(kty, "EC", "RSA", "oct", NULL)) {
    case 0:
        ec = jose_openssl_jwk_to_EC_KEY(cfg, jwk);
        if (!ec)
            return NULL;

        key = EVP_PKEY_new();
        if (!key)
            return NULL;

        if (EVP_PKEY_set1_EC_KEY(key, ec) > 0)
            return key;

        EVP_PKEY_free(key);
        return NULL;

    case 1:
        rsa = jose_openssl_jwk_to_RSA(cfg, jwk);
        if (!rsa)
            return NULL;

        key = EVP_PKEY_new();
        if (!key)
            return NULL;

        if (EVP_PKEY_set1_RSA(key, rsa) > 0)
            return key;

        EVP_PKEY_free(key);
        return NULL;

    case 2:
        len = jose_b64_dec(json_object_get(jwk, "k"), NULL, 0);
        if (len == SIZE_MAX)
            return NULL;

        buf = malloc(len);
        if (!buf)
            return NULL;

        if (jose_b64_dec(json_object_get(jwk, "k"), buf, len) != len) {
            OPENSSL_cleanse(buf, len);
            free(buf);
            return NULL;
        }

        key = EVP_PKEY_new_mac_key(EVP_PKEY_HMAC, NULL, buf, len);
        OPENSSL_cleanse(buf, len);
        free(buf);
        return key;

    default: return NULL;
    }
}

RSA *
jose_openssl_jwk_to_RSA(jose_cfg_t *cfg, const json_t *jwk)
{
    openssl_auto(RSA) *rsa = NULL;
    const json_t *n = NULL;
    const json_t *e = NULL;
    const json_t *d = NULL;
    const json_t *p = NULL;
    const json_t *q = NULL;
    const json_t *dp = NULL;
    const json_t *dq = NULL;
    const json_t *qi = NULL;
    const char *kty = NULL;
    BIGNUM *N = NULL;
    BIGNUM *E = NULL;
    BIGNUM *D = NULL;
    BIGNUM *P = NULL;
    BIGNUM *Q = NULL;
    BIGNUM *DP = NULL;
    BIGNUM *DQ = NULL;
    BIGNUM *QI = NULL;

    if (json_unpack((json_t *) jwk, "{s:s,s:o,s:o,s?o,s?o,s?o,s?o,s?o,s?o}",
                    "kty", &kty, "n", &n, "e", &e, "d", &d, "p", &p,
                    "q", &q, "dp", &dp, "dq", &dq, "qi", &qi) != 0)
        return NULL;

    rsa = RSA_new();
    if (!rsa)
        return NULL;

    N = bn_decode_json(n);
    E = bn_decode_json(e);
    P = bn_decode_json(p);
    Q = bn_decode_json(q);
    DP = bn_decode_json(dp);
    DQ = bn_decode_json(dq);
    QI = bn_decode_json(qi);
    if ((!n || N) && (!e || E) && (!p || P) && (!q || Q) &&
        (!dp || DP) && (!dq || DQ) && (!qi || QI)) {
        if (RSA_set0_key(rsa, N, E, D) > 0) {
            N = NULL;
            E = NULL;
            D = NULL;

            if ((!P && !Q) ||
                RSA_set0_factors(rsa, P, Q) > 0) {
                P = NULL;
                Q = NULL;

                if ((!DP && !DQ && !QI) ||
                    RSA_set0_crt_params(rsa, DP, DQ, QI) > 0) {
                    DP = NULL;
                    DQ = NULL;
                    QI = NULL;

                    if (RSA_up_ref(rsa) > 0)
                        return rsa;
                }
            }
        }
    }

    BN_free(N);
    BN_free(E);
    BN_free(P);
    BN_free(Q);
    BN_free(DP);
    BN_free(DQ);
    BN_free(QI);
    return NULL;
}

EC_KEY *
jose_openssl_jwk_to_EC_KEY(jose_cfg_t *cfg, const json_t *jwk)
{
    openssl_auto(EC_POINT) *pub = NULL;
    openssl_auto(EC_KEY) *key = NULL;
    openssl_auto(BIGNUM) *D = NULL;
    const char *kty = NULL;
    const char *crv = NULL;
    const json_t *x = NULL;
    const json_t *y = NULL;
    const json_t *d = NULL;
    int nid = NID_undef;

    if (json_unpack((json_t *) jwk, "{s:s,s:s,s:o,s:o,s?o}", "kty", &kty,
                    "crv", &crv, "x", &x, "y", &y, "d", &d) == -1)
        return NULL;

    if (strcmp(kty, "EC") != 0)
        return NULL;

    switch (str2enum(crv, "P-256", "P-384", "P-521", NULL)) {
    case 0: nid = NID_X9_62_prime256v1; break;
    case 1: nid = NID_secp384r1; break;
    case 2: nid = NID_secp521r1; break;
    default: return NULL;
    }

    key = EC_KEY_new_by_curve_name(nid);
    if (!key)
        return NULL;

    if (d) {
        D = bn_decode_json(d);
        if (!D)
            return NULL;

        if (EC_KEY_set_private_key(key, D) < 0)
            return NULL;
    }

    pub = mkpub(EC_KEY_get0_group(key), x, y, D);
    if (!pub)
        return NULL;

    if (EC_KEY_set_public_key(key, pub) < 0)
        return NULL;

    if (EC_KEY_check_key(key) == 0)
        return NULL;

    return EC_KEY_up_ref(key) <= 0 ? NULL : key;
}