/*

 * Copyright 2006-2016 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include <stdio.h>

#include "internal/cryptlib.h"

#include <openssl/x509.h>

#include <openssl/asn1.h>

#include "dsa_locl.h"

#include <openssl/bn.h>

#include <openssl/cms.h>

#include "internal/asn1_int.h"

#include "internal/evp_int.h"

static int dsa_pub_decode(EVP_PKEY *pkey, X509_PUBKEY *pubkey)

{

    const unsigned char *p, *pm;

    int pklen, pmlen;

    int ptype;

    const void *pval;

    const 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)) == NULL) {

            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()) == NULL) {

            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)) == NULL) {

        DSAerr(DSA_F_DSA_PUB_DECODE, DSA_R_DECODE_ERROR);

        goto err;

    }

    if ((dsa->pub_key = ASN1_INTEGER_to_BN(public_key, NULL)) == 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:

    ASN1_INTEGER_free(public_key);

    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;

    ASN1_INTEGER *pubint = NULL;

    ASN1_OBJECT *aobj;

    dsa = pkey->pkey.dsa;

    if (pkey->save_parameters && dsa->p && dsa->q && dsa->g) {

        str = ASN1_STRING_new();

        if (str == NULL) {

            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;

    pubint = BN_to_ASN1_INTEGER(dsa->pub_key, NULL);

    if (pubint == NULL) {

        DSAerr(DSA_F_DSA_PUB_ENCODE, ERR_R_MALLOC_FAILURE);

        goto err;

    }

    penclen = i2d_ASN1_INTEGER(pubint, &penc);

    ASN1_INTEGER_free(pubint);

    if (penclen <= 0) {

        DSAerr(DSA_F_DSA_PUB_ENCODE, ERR_R_MALLOC_FAILURE);

        goto err;

    }

    aobj = OBJ_nid2obj(EVP_PKEY_DSA);

    if (aobj == NULL)

        goto err;

    if (X509_PUBKEY_set0_param(pk, aobj, ptype, str, penc, penclen))

        return 1;

 err:

    OPENSSL_free(penc);

    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, const PKCS8_PRIV_KEY_INFO *p8)

{

    const unsigned char *p, *pm;

    int pklen, pmlen;

    int ptype;

    const void *pval;

    const ASN1_STRING *pstr;

    const X509_ALGOR *palg;

    ASN1_INTEGER *privkey = NULL;

    BN_CTX *ctx = 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);

    if ((privkey = d2i_ASN1_INTEGER(NULL, &p, pklen)) == NULL)

        goto decerr;

    if (privkey->type == V_ASN1_NEG_INTEGER || ptype != V_ASN1_SEQUENCE)

        goto decerr;

    pstr = pval;

    pm = pstr->data;

    pmlen = pstr->length;

    if ((dsa = d2i_DSAparams(NULL, &pm, pmlen)) == NULL)

        goto decerr;

    /* We have parameters now set private key */

    if ((dsa->priv_key = BN_secure_new()) == NULL

        || !ASN1_INTEGER_to_BN(privkey, dsa->priv_key)) {

        DSAerr(DSA_F_DSA_PRIV_DECODE, DSA_R_BN_ERROR);

        goto dsaerr;

    }

    /* Calculate public key */

    if ((dsa->pub_key = BN_new()) == NULL) {

        DSAerr(DSA_F_DSA_PRIV_DECODE, ERR_R_MALLOC_FAILURE);

        goto dsaerr;

    }

    if ((ctx = BN_CTX_new()) == NULL) {

        DSAerr(DSA_F_DSA_PRIV_DECODE, ERR_R_MALLOC_FAILURE);

        goto dsaerr;

    }

    BN_set_flags(dsa->priv_key, BN_FLG_CONSTTIME);

    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, DSA_R_DECODE_ERROR);

 dsaerr:

    DSA_free(dsa);

 done:

    BN_CTX_free(ctx);

    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 == NULL) {

        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:

    OPENSSL_free(dp);

    ASN1_STRING_free(params);

    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 DSA_bits(pkey->pkey.dsa);

}

static int dsa_security_bits(const EVP_PKEY *pkey)

{

    return DSA_security_bits(pkey->pkey.dsa);

}

static int dsa_missing_parameters(const EVP_PKEY *pkey)

{

    DSA *dsa;

    dsa = pkey->pkey.dsa;

    if (dsa == NULL || 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 (to->pkey.dsa == NULL) {

        to->pkey.dsa = DSA_new();

        if (to->pkey.dsa == NULL)

            return 0;

    }

    if ((a = BN_dup(from->pkey.dsa->p)) == NULL)

        return 0;

    BN_free(to->pkey.dsa->p);

    to->pkey.dsa->p = a;

    if ((a = BN_dup(from->pkey.dsa->q)) == NULL)

        return 0;

    BN_free(to->pkey.dsa->q);

    to->pkey.dsa->q = a;

    if ((a = BN_dup(from->pkey.dsa->g)) == NULL)

        return 0;

    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 int do_dsa_print(BIO *bp, const DSA *x, int off, int ptype)

{

    int ret = 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";

    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, NULL, off))

        goto err;

    if (!ASN1_bn_print(bp, "pub: ", pub_key, NULL, off))

        goto err;

    if (!ASN1_bn_print(bp, "P:   ", x->p, NULL, off))

        goto err;

    if (!ASN1_bn_print(bp, "Q:   ", x->q, NULL, off))

        goto err;

    if (!ASN1_bn_print(bp, "G:   ", x->g, NULL, off))

        goto err;

    ret = 1;

 err:

    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)) == NULL) {

        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)) == NULL) {

        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;

        const BIGNUM *r, *s;

        DSA_SIG_get0(dsa_sig, &r, &s);

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

            goto err;

        if (!ASN1_bn_print(bp, "r:   ", r, NULL, indent))

            goto err;

        if (!ASN1_bn_print(bp, "s:   ", s, NULL, indent))

            goto err;

        rv = 1;

 err:

        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;

    case ASN1_PKEY_CTRL_CMS_RI_TYPE:

        *(int *)arg2 = CMS_RECIPINFO_NONE;

        return 1;

#endif

    case ASN1_PKEY_CTRL_DEFAULT_MD_NID:

        *(int *)arg2 = NID_sha256;

        return 2;

    default:

        return -2;

    }

}

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

const EVP_PKEY_ASN1_METHOD dsa_asn1_meths[5] = {

    {

     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_security_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}

};