/*
 * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL project
 * 2006.
 */
/* ====================================================================
 * Copyright (c) 2006 The OpenSSL Project.  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.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED 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 OpenSSL PROJECT OR
 * ITS 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.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#include <stdio.h>
#include "cryptlib.h"
#include <openssl/x509.h>
#include <openssl/asn1.h>
#include <openssl/dsa.h>
#include <openssl/bn.h>
#ifndef OPENSSL_NO_CMS
# include <openssl/cms.h>
#endif
#include "asn1_locl.h"

static int dsa_pub_decode(EVP_PKEY *pkey, X509_PUBKEY *pubkey)
{
    const unsigned char *p, *pm;
    int pklen, pmlen;
    int ptype;
    void *pval;
    ASN1_STRING *pstr;
    X509_ALGOR *palg;
    ASN1_INTEGER *public_key = NULL;

    DSA *dsa = NULL;

    if (!X509_PUBKEY_get0_param(NULL, &p, &pklen, &palg, pubkey))
        return 0;
    X509_ALGOR_get0(NULL, &ptype, &pval, palg);

    if (ptype == V_ASN1_SEQUENCE) {
        pstr = pval;
        pm = pstr->data;
        pmlen = pstr->length;

        if (!(dsa = d2i_DSAparams(NULL, &pm, pmlen))) {
            DSAerr(DSA_F_DSA_PUB_DECODE, DSA_R_DECODE_ERROR);
            goto err;
        }

    } else if ((ptype == V_ASN1_NULL) || (ptype == V_ASN1_UNDEF)) {
        if (!(dsa = DSA_new())) {
            DSAerr(DSA_F_DSA_PUB_DECODE, ERR_R_MALLOC_FAILURE);
            goto err;
        }
    } else {
        DSAerr(DSA_F_DSA_PUB_DECODE, DSA_R_PARAMETER_ENCODING_ERROR);
        goto err;
    }

    if (!(public_key = d2i_ASN1_INTEGER(NULL, &p, pklen))) {
        DSAerr(DSA_F_DSA_PUB_DECODE, DSA_R_DECODE_ERROR);
        goto err;
    }

    if (!(dsa->pub_key = ASN1_INTEGER_to_BN(public_key, NULL))) {
        DSAerr(DSA_F_DSA_PUB_DECODE, DSA_R_BN_DECODE_ERROR);
        goto err;
    }

    ASN1_INTEGER_free(public_key);
    EVP_PKEY_assign_DSA(pkey, dsa);
    return 1;

 err:
    if (public_key)
        ASN1_INTEGER_free(public_key);
    if (dsa)
        DSA_free(dsa);
    return 0;

}

static int dsa_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)
{
    DSA *dsa;
    int ptype;
    unsigned char *penc = NULL;
    int penclen;
    ASN1_STRING *str = NULL;

    dsa = pkey->pkey.dsa;
    if (pkey->save_parameters && dsa->p && dsa->q && dsa->g) {
        str = ASN1_STRING_new();
        if (!str) {
            DSAerr(DSA_F_DSA_PUB_ENCODE, ERR_R_MALLOC_FAILURE);
            goto err;
        }
        str->length = i2d_DSAparams(dsa, &str->data);
        if (str->length <= 0) {
            DSAerr(DSA_F_DSA_PUB_ENCODE, ERR_R_MALLOC_FAILURE);
            goto err;
        }
        ptype = V_ASN1_SEQUENCE;
    } else
        ptype = V_ASN1_UNDEF;

    dsa->write_params = 0;

    penclen = i2d_DSAPublicKey(dsa, &penc);

    if (penclen <= 0) {
        DSAerr(DSA_F_DSA_PUB_ENCODE, ERR_R_MALLOC_FAILURE);
        goto err;
    }

    if (X509_PUBKEY_set0_param(pk, OBJ_nid2obj(EVP_PKEY_DSA),
                               ptype, str, penc, penclen))
        return 1;

 err:
    if (penc)
        OPENSSL_free(penc);
    if (str)
        ASN1_STRING_free(str);

    return 0;
}

/*
 * In PKCS#8 DSA: you just get a private key integer and parameters in the
 * AlgorithmIdentifier the pubkey must be recalculated.
 */

static int dsa_priv_decode(EVP_PKEY *pkey, PKCS8_PRIV_KEY_INFO *p8)
{
    const unsigned char *p, *pm;
    int pklen, pmlen;
    int ptype;
    void *pval;
    ASN1_STRING *pstr;
    X509_ALGOR *palg;
    ASN1_INTEGER *privkey = NULL;
    BN_CTX *ctx = NULL;

    STACK_OF(ASN1_TYPE) *ndsa = NULL;
    DSA *dsa = NULL;

    int ret = 0;

    if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8))
        return 0;
    X509_ALGOR_get0(NULL, &ptype, &pval, palg);

    /* Check for broken DSA PKCS#8, UGH! */
    if (*p == (V_ASN1_SEQUENCE | V_ASN1_CONSTRUCTED)) {
        ASN1_TYPE *t1, *t2;
        if (!(ndsa = d2i_ASN1_SEQUENCE_ANY(NULL, &p, pklen)))
            goto decerr;
        if (sk_ASN1_TYPE_num(ndsa) != 2)
            goto decerr;
        /*-
         * Handle Two broken types:
         * SEQUENCE {parameters, priv_key}
         * SEQUENCE {pub_key, priv_key}
         */

        t1 = sk_ASN1_TYPE_value(ndsa, 0);
        t2 = sk_ASN1_TYPE_value(ndsa, 1);
        if (t1->type == V_ASN1_SEQUENCE) {
            p8->broken = PKCS8_EMBEDDED_PARAM;
            pval = t1->value.ptr;
        } else if (ptype == V_ASN1_SEQUENCE)
            p8->broken = PKCS8_NS_DB;
        else
            goto decerr;

        if (t2->type != V_ASN1_INTEGER)
            goto decerr;

        privkey = t2->value.integer;
    } else {
        const unsigned char *q = p;
        if (!(privkey = d2i_ASN1_INTEGER(NULL, &p, pklen)))
            goto decerr;
        if (privkey->type == V_ASN1_NEG_INTEGER) {
            p8->broken = PKCS8_NEG_PRIVKEY;
            ASN1_STRING_clear_free(privkey);
            if (!(privkey = d2i_ASN1_UINTEGER(NULL, &q, pklen)))
                goto decerr;
        }
        if (ptype != V_ASN1_SEQUENCE)
            goto decerr;
    }

    pstr = pval;
    pm = pstr->data;
    pmlen = pstr->length;
    if (!(dsa = d2i_DSAparams(NULL, &pm, pmlen)))
        goto decerr;
    /* We have parameters now set private key */
    if (!(dsa->priv_key = ASN1_INTEGER_to_BN(privkey, NULL))) {
        DSAerr(DSA_F_DSA_PRIV_DECODE, DSA_R_BN_ERROR);
        goto dsaerr;
    }
    /* Calculate public key */
    if (!(dsa->pub_key = BN_new())) {
        DSAerr(DSA_F_DSA_PRIV_DECODE, ERR_R_MALLOC_FAILURE);
        goto dsaerr;
    }
    if (!(ctx = BN_CTX_new())) {
        DSAerr(DSA_F_DSA_PRIV_DECODE, ERR_R_MALLOC_FAILURE);
        goto dsaerr;
    }

    if (!BN_mod_exp(dsa->pub_key, dsa->g, dsa->priv_key, dsa->p, ctx)) {
        DSAerr(DSA_F_DSA_PRIV_DECODE, DSA_R_BN_ERROR);
        goto dsaerr;
    }

    EVP_PKEY_assign_DSA(pkey, dsa);

    ret = 1;
    goto done;

 decerr:
    DSAerr(DSA_F_DSA_PRIV_DECODE, EVP_R_DECODE_ERROR);
 dsaerr:
    DSA_free(dsa);
 done:
    BN_CTX_free(ctx);
    if (ndsa)
        sk_ASN1_TYPE_pop_free(ndsa, ASN1_TYPE_free);
    else
        ASN1_STRING_clear_free(privkey);
    return ret;
}

static int dsa_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)
{
    ASN1_STRING *params = NULL;
    ASN1_INTEGER *prkey = NULL;
    unsigned char *dp = NULL;
    int dplen;

    if (!pkey->pkey.dsa || !pkey->pkey.dsa->priv_key) {
        DSAerr(DSA_F_DSA_PRIV_ENCODE, DSA_R_MISSING_PARAMETERS);
        goto err;
    }

    params = ASN1_STRING_new();

    if (!params) {
        DSAerr(DSA_F_DSA_PRIV_ENCODE, ERR_R_MALLOC_FAILURE);
        goto err;
    }

    params->length = i2d_DSAparams(pkey->pkey.dsa, &params->data);
    if (params->length <= 0) {
        DSAerr(DSA_F_DSA_PRIV_ENCODE, ERR_R_MALLOC_FAILURE);
        goto err;
    }
    params->type = V_ASN1_SEQUENCE;

    /* Get private key into integer */
    prkey = BN_to_ASN1_INTEGER(pkey->pkey.dsa->priv_key, NULL);

    if (!prkey) {
        DSAerr(DSA_F_DSA_PRIV_ENCODE, DSA_R_BN_ERROR);
        goto err;
    }

    dplen = i2d_ASN1_INTEGER(prkey, &dp);

    ASN1_STRING_clear_free(prkey);
    prkey = NULL;

    if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(NID_dsa), 0,
                         V_ASN1_SEQUENCE, params, dp, dplen))
        goto err;

    return 1;

 err:
    if (dp != NULL)
        OPENSSL_free(dp);
    if (params != NULL)
        ASN1_STRING_free(params);
    if (prkey != NULL)
        ASN1_STRING_clear_free(prkey);
    return 0;
}

static int int_dsa_size(const EVP_PKEY *pkey)
{
    return (DSA_size(pkey->pkey.dsa));
}

static int dsa_bits(const EVP_PKEY *pkey)
{
    return BN_num_bits(pkey->pkey.dsa->p);
}

static int dsa_missing_parameters(const EVP_PKEY *pkey)
{
    DSA *dsa;
    dsa = pkey->pkey.dsa;
    if ((dsa->p == NULL) || (dsa->q == NULL) || (dsa->g == NULL))
        return 1;
    return 0;
}

static int dsa_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)
{
    BIGNUM *a;

    if ((a = BN_dup(from->pkey.dsa->p)) == NULL)
        return 0;
    if (to->pkey.dsa->p != NULL)
        BN_free(to->pkey.dsa->p);
    to->pkey.dsa->p = a;

    if ((a = BN_dup(from->pkey.dsa->q)) == NULL)
        return 0;
    if (to->pkey.dsa->q != NULL)
        BN_free(to->pkey.dsa->q);
    to->pkey.dsa->q = a;

    if ((a = BN_dup(from->pkey.dsa->g)) == NULL)
        return 0;
    if (to->pkey.dsa->g != NULL)
        BN_free(to->pkey.dsa->g);
    to->pkey.dsa->g = a;
    return 1;
}

static int dsa_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b)
{
    if (BN_cmp(a->pkey.dsa->p, b->pkey.dsa->p) ||
        BN_cmp(a->pkey.dsa->q, b->pkey.dsa->q) ||
        BN_cmp(a->pkey.dsa->g, b->pkey.dsa->g))
        return 0;
    else
        return 1;
}

static int dsa_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)
{
    if (BN_cmp(b->pkey.dsa->pub_key, a->pkey.dsa->pub_key) != 0)
        return 0;
    else
        return 1;
}

static void int_dsa_free(EVP_PKEY *pkey)
{
    DSA_free(pkey->pkey.dsa);
}

static void update_buflen(const BIGNUM *b, size_t *pbuflen)
{
    size_t i;
    if (!b)
        return;
    if (*pbuflen < (i = (size_t)BN_num_bytes(b)))
        *pbuflen = i;
}

static int do_dsa_print(BIO *bp, const DSA *x, int off, int ptype)
{
    unsigned char *m = NULL;
    int ret = 0;
    size_t buf_len = 0;
    const char *ktype = NULL;

    const BIGNUM *priv_key, *pub_key;

    if (ptype == 2)
        priv_key = x->priv_key;
    else
        priv_key = NULL;

    if (ptype > 0)
        pub_key = x->pub_key;
    else
        pub_key = NULL;

    if (ptype == 2)
        ktype = "Private-Key";
    else if (ptype == 1)
        ktype = "Public-Key";
    else
        ktype = "DSA-Parameters";

    update_buflen(x->p, &buf_len);
    update_buflen(x->q, &buf_len);
    update_buflen(x->g, &buf_len);
    update_buflen(priv_key, &buf_len);
    update_buflen(pub_key, &buf_len);

    m = (unsigned char *)OPENSSL_malloc(buf_len + 10);
    if (m == NULL) {
        DSAerr(DSA_F_DO_DSA_PRINT, ERR_R_MALLOC_FAILURE);
        goto err;
    }

    if (priv_key) {
        if (!BIO_indent(bp, off, 128))
            goto err;
        if (BIO_printf(bp, "%s: (%d bit)\n", ktype, BN_num_bits(x->p))
            <= 0)
            goto err;
    }

    if (!ASN1_bn_print(bp, "priv:", priv_key, m, off))
        goto err;
    if (!ASN1_bn_print(bp, "pub: ", pub_key, m, off))
        goto err;
    if (!ASN1_bn_print(bp, "P:   ", x->p, m, off))
        goto err;
    if (!ASN1_bn_print(bp, "Q:   ", x->q, m, off))
        goto err;
    if (!ASN1_bn_print(bp, "G:   ", x->g, m, off))
        goto err;
    ret = 1;
 err:
    if (m != NULL)
        OPENSSL_free(m);
    return (ret);
}

static int dsa_param_decode(EVP_PKEY *pkey,
                            const unsigned char **pder, int derlen)
{
    DSA *dsa;
    if (!(dsa = d2i_DSAparams(NULL, pder, derlen))) {
        DSAerr(DSA_F_DSA_PARAM_DECODE, ERR_R_DSA_LIB);
        return 0;
    }
    EVP_PKEY_assign_DSA(pkey, dsa);
    return 1;
}

static int dsa_param_encode(const EVP_PKEY *pkey, unsigned char **pder)
{
    return i2d_DSAparams(pkey->pkey.dsa, pder);
}

static int dsa_param_print(BIO *bp, const EVP_PKEY *pkey, int indent,
                           ASN1_PCTX *ctx)
{
    return do_dsa_print(bp, pkey->pkey.dsa, indent, 0);
}

static int dsa_pub_print(BIO *bp, const EVP_PKEY *pkey, int indent,
                         ASN1_PCTX *ctx)
{
    return do_dsa_print(bp, pkey->pkey.dsa, indent, 1);
}

static int dsa_priv_print(BIO *bp, const EVP_PKEY *pkey, int indent,
                          ASN1_PCTX *ctx)
{
    return do_dsa_print(bp, pkey->pkey.dsa, indent, 2);
}

static int old_dsa_priv_decode(EVP_PKEY *pkey,
                               const unsigned char **pder, int derlen)
{
    DSA *dsa;
    if (!(dsa = d2i_DSAPrivateKey(NULL, pder, derlen))) {
        DSAerr(DSA_F_OLD_DSA_PRIV_DECODE, ERR_R_DSA_LIB);
        return 0;
    }
    EVP_PKEY_assign_DSA(pkey, dsa);
    return 1;
}

static int old_dsa_priv_encode(const EVP_PKEY *pkey, unsigned char **pder)
{
    return i2d_DSAPrivateKey(pkey->pkey.dsa, pder);
}

static int dsa_sig_print(BIO *bp, const X509_ALGOR *sigalg,
                         const ASN1_STRING *sig, int indent, ASN1_PCTX *pctx)
{
    DSA_SIG *dsa_sig;
    const unsigned char *p;
    if (!sig) {
        if (BIO_puts(bp, "\n") <= 0)
            return 0;
        else
            return 1;
    }
    p = sig->data;
    dsa_sig = d2i_DSA_SIG(NULL, &p, sig->length);
    if (dsa_sig) {
        int rv = 0;
        size_t buf_len = 0;
        unsigned char *m = NULL;
        update_buflen(dsa_sig->r, &buf_len);
        update_buflen(dsa_sig->s, &buf_len);
        m = OPENSSL_malloc(buf_len + 10);
        if (m == NULL) {
            DSAerr(DSA_F_DSA_SIG_PRINT, ERR_R_MALLOC_FAILURE);
            goto err;
        }

        if (BIO_write(bp, "\n", 1) != 1)
            goto err;

        if (!ASN1_bn_print(bp, "r:   ", dsa_sig->r, m, indent))
            goto err;
        if (!ASN1_bn_print(bp, "s:   ", dsa_sig->s, m, indent))
            goto err;
        rv = 1;
 err:
        if (m)
            OPENSSL_free(m);
        DSA_SIG_free(dsa_sig);
        return rv;
    }
    return X509_signature_dump(bp, sig, indent);
}

static int dsa_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)
{
    switch (op) {
    case ASN1_PKEY_CTRL_PKCS7_SIGN:
        if (arg1 == 0) {
            int snid, hnid;
            X509_ALGOR *alg1, *alg2;
            PKCS7_SIGNER_INFO_get0_algs(arg2, NULL, &alg1, &alg2);
            if (alg1 == NULL || alg1->algorithm == NULL)
                return -1;
            hnid = OBJ_obj2nid(alg1->algorithm);
            if (hnid == NID_undef)
                return -1;
            if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_id(pkey)))
                return -1;
            X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);
        }
        return 1;
#ifndef OPENSSL_NO_CMS
    case ASN1_PKEY_CTRL_CMS_SIGN:
        if (arg1 == 0) {
            int snid, hnid;
            X509_ALGOR *alg1, *alg2;
            CMS_SignerInfo_get0_algs(arg2, NULL, NULL, &alg1, &alg2);
            if (alg1 == NULL || alg1->algorithm == NULL)
                return -1;
            hnid = OBJ_obj2nid(alg1->algorithm);
            if (hnid == NID_undef)
                return -1;
            if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_id(pkey)))
                return -1;
            X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);
        }
        return 1;
#endif

    case ASN1_PKEY_CTRL_DEFAULT_MD_NID:
        *(int *)arg2 = NID_sha1;
        return 2;

    default:
        return -2;

    }

}

/* NB these are sorted in pkey_id order, lowest first */

const EVP_PKEY_ASN1_METHOD dsa_asn1_meths[] = {

    {
     EVP_PKEY_DSA2,
     EVP_PKEY_DSA,
     ASN1_PKEY_ALIAS},

    {
     EVP_PKEY_DSA1,
     EVP_PKEY_DSA,
     ASN1_PKEY_ALIAS},

    {
     EVP_PKEY_DSA4,
     EVP_PKEY_DSA,
     ASN1_PKEY_ALIAS},

    {
     EVP_PKEY_DSA3,
     EVP_PKEY_DSA,
     ASN1_PKEY_ALIAS},

    {
     EVP_PKEY_DSA,
     EVP_PKEY_DSA,
     0,

     "DSA",
     "OpenSSL DSA method",

     dsa_pub_decode,
     dsa_pub_encode,
     dsa_pub_cmp,
     dsa_pub_print,

     dsa_priv_decode,
     dsa_priv_encode,
     dsa_priv_print,

     int_dsa_size,
     dsa_bits,

     dsa_param_decode,
     dsa_param_encode,
     dsa_missing_parameters,
     dsa_copy_parameters,
     dsa_cmp_parameters,
     dsa_param_print,
     dsa_sig_print,

     int_dsa_free,
     dsa_pkey_ctrl,
     old_dsa_priv_decode,
     old_dsa_priv_encode}
};
