/*

 * Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (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

 */

/*

 * DSA low level APIs are deprecated for public use, but still ok for

 * internal use.

 */

#include "internal/deprecated.h"

#include <string.h>

#include <openssl/crypto.h>

#include <openssl/core_dispatch.h>

#include <openssl/core_names.h>

#include <openssl/err.h>

#include <openssl/dsa.h>

#include <openssl/params.h>

#include <openssl/evp.h>

#include <openssl/err.h>

#include <openssl/proverr.h>

#include "internal/nelem.h"

#include "internal/sizes.h"

#include "internal/cryptlib.h"

#include "prov/providercommon.h"

#include "prov/implementations.h"

#include "prov/provider_ctx.h"

#include "prov/securitycheck.h"

#include "crypto/dsa.h"

#include "prov/der_dsa.h"

static OSSL_FUNC_signature_newctx_fn dsa_newctx;

static OSSL_FUNC_signature_sign_init_fn dsa_sign_init;

static OSSL_FUNC_signature_verify_init_fn dsa_verify_init;

static OSSL_FUNC_signature_sign_fn dsa_sign;

static OSSL_FUNC_signature_verify_fn dsa_verify;

static OSSL_FUNC_signature_digest_sign_init_fn dsa_digest_sign_init;

static OSSL_FUNC_signature_digest_sign_update_fn dsa_digest_signverify_update;

static OSSL_FUNC_signature_digest_sign_final_fn dsa_digest_sign_final;

static OSSL_FUNC_signature_digest_verify_init_fn dsa_digest_verify_init;

static OSSL_FUNC_signature_digest_verify_update_fn dsa_digest_signverify_update;

static OSSL_FUNC_signature_digest_verify_final_fn dsa_digest_verify_final;

static OSSL_FUNC_signature_freectx_fn dsa_freectx;

static OSSL_FUNC_signature_dupctx_fn dsa_dupctx;

static OSSL_FUNC_signature_get_ctx_params_fn dsa_get_ctx_params;

static OSSL_FUNC_signature_gettable_ctx_params_fn dsa_gettable_ctx_params;

static OSSL_FUNC_signature_set_ctx_params_fn dsa_set_ctx_params;

static OSSL_FUNC_signature_settable_ctx_params_fn dsa_settable_ctx_params;

static OSSL_FUNC_signature_get_ctx_md_params_fn dsa_get_ctx_md_params;

static OSSL_FUNC_signature_gettable_ctx_md_params_fn dsa_gettable_ctx_md_params;

static OSSL_FUNC_signature_set_ctx_md_params_fn dsa_set_ctx_md_params;

static OSSL_FUNC_signature_settable_ctx_md_params_fn dsa_settable_ctx_md_params;

/*

 * What's passed as an actual key is defined by the KEYMGMT interface.

 * We happen to know that our KEYMGMT simply passes DSA structures, so

 * we use that here too.

 */

typedef struct {

    OSSL_LIB_CTX *libctx;

    char *propq;

    DSA *dsa;

    /*

     * Flag to determine if the hash function can be changed (1) or not (0)

     * Because it's dangerous to change during a DigestSign or DigestVerify

     * operation, this flag is cleared by their Init function, and set again

     * by their Final function.

     */

    unsigned int flag_allow_md : 1;

    char mdname[OSSL_MAX_NAME_SIZE];

    /* The Algorithm Identifier of the combined signature algorithm */

    unsigned char aid_buf[OSSL_MAX_ALGORITHM_ID_SIZE];

    unsigned char *aid;

    size_t aid_len;

    /* main digest */

    EVP_MD *md;

    EVP_MD_CTX *mdctx;

    int operation;

} PROV_DSA_CTX;

static size_t dsa_get_md_size(const PROV_DSA_CTX *pdsactx)

{

    if (pdsactx->md != NULL)

        return EVP_MD_get_size(pdsactx->md);

    return 0;

}

static void *dsa_newctx(void *provctx, const char *propq)

{

    PROV_DSA_CTX *pdsactx;

    if (!ossl_prov_is_running())

        return NULL;

    pdsactx = OPENSSL_zalloc(sizeof(PROV_DSA_CTX));

    if (pdsactx == NULL)

        return NULL;

    pdsactx->libctx = PROV_LIBCTX_OF(provctx);

    pdsactx->flag_allow_md = 1;

    if (propq != NULL && (pdsactx->propq = OPENSSL_strdup(propq)) == NULL) {

        OPENSSL_free(pdsactx);

        pdsactx = NULL;

        ERR_raise(ERR_LIB_PROV, ERR_R_MALLOC_FAILURE);

    }

    return pdsactx;

}

static int dsa_setup_md(PROV_DSA_CTX *ctx,

    const char *mdname, const char *mdprops)

{

    if (mdprops == NULL)

        mdprops = ctx->propq;

    if (mdname != NULL) {

        int sha1_allowed = (ctx->operation != EVP_PKEY_OP_SIGN);

        WPACKET pkt;

        EVP_MD *md = EVP_MD_fetch(ctx->libctx, mdname, mdprops);

        int md_nid = ossl_digest_get_approved_nid_with_sha1(ctx->libctx, md,

            sha1_allowed);

        size_t mdname_len = strlen(mdname);

        if (md == NULL || md_nid < 0) {

            if (md == NULL)

                ERR_raise_data(ERR_LIB_PROV, PROV_R_INVALID_DIGEST,

                    "%s could not be fetched", mdname);

            if (md_nid < 0)

                ERR_raise_data(ERR_LIB_PROV, PROV_R_DIGEST_NOT_ALLOWED,

                    "digest=%s", mdname);

            if (mdname_len >= sizeof(ctx->mdname))

                ERR_raise_data(ERR_LIB_PROV, PROV_R_INVALID_DIGEST,

                    "%s exceeds name buffer length", mdname);

            EVP_MD_free(md);

            return 0;

        }

        if (!ctx->flag_allow_md) {

            if (ctx->mdname[0] != '\0' && !EVP_MD_is_a(md, ctx->mdname)) {

                ERR_raise_data(ERR_LIB_PROV, PROV_R_DIGEST_NOT_ALLOWED,

                    "digest %s != %s", mdname, ctx->mdname);

                EVP_MD_free(md);

                return 0;

            }

            EVP_MD_free(md);

            return 1;

        }

        EVP_MD_CTX_free(ctx->mdctx);

        EVP_MD_free(ctx->md);

        /*

         * We do not care about DER writing errors.

         * All it really means is that for some reason, there's no

         * AlgorithmIdentifier to be had, but the operation itself is

         * still valid, just as long as it's not used to construct

         * anything that needs an AlgorithmIdentifier.

         */

        ctx->aid_len = 0;

        if (WPACKET_init_der(&pkt, ctx->aid_buf, sizeof(ctx->aid_buf))

            && ossl_DER_w_algorithmIdentifier_DSA_with_MD(&pkt, -1, ctx->dsa,

                md_nid)

            && WPACKET_finish(&pkt)) {

            WPACKET_get_total_written(&pkt, &ctx->aid_len);

            ctx->aid = WPACKET_get_curr(&pkt);

        }

        WPACKET_cleanup(&pkt);

        ctx->mdctx = NULL;

        ctx->md = md;

        OPENSSL_strlcpy(ctx->mdname, mdname, sizeof(ctx->mdname));

    }

    return 1;

}

static int dsa_signverify_init(void *vpdsactx, void *vdsa,

    const OSSL_PARAM params[], int operation)

{

    PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;

    if (!ossl_prov_is_running()

        || pdsactx == NULL)

        return 0;

    if (vdsa == NULL && pdsactx->dsa == NULL) {

        ERR_raise(ERR_LIB_PROV, PROV_R_NO_KEY_SET);

        return 0;

    }

    if (vdsa != NULL) {

        if (!ossl_dsa_check_key(pdsactx->libctx, vdsa,

                operation == EVP_PKEY_OP_SIGN)) {

            ERR_raise(ERR_LIB_PROV, PROV_R_INVALID_KEY_LENGTH);

            return 0;

        }

        if (!DSA_up_ref(vdsa))

            return 0;

        DSA_free(pdsactx->dsa);

        pdsactx->dsa = vdsa;

    }

    pdsactx->operation = operation;

    if (!dsa_set_ctx_params(pdsactx, params))

        return 0;

    return 1;

}

static int dsa_sign_init(void *vpdsactx, void *vdsa, const OSSL_PARAM params[])

{

    return dsa_signverify_init(vpdsactx, vdsa, params, EVP_PKEY_OP_SIGN);

}

static int dsa_verify_init(void *vpdsactx, void *vdsa,

    const OSSL_PARAM params[])

{

    return dsa_signverify_init(vpdsactx, vdsa, params, EVP_PKEY_OP_VERIFY);

}

static int dsa_sign(void *vpdsactx, unsigned char *sig, size_t *siglen,

    size_t sigsize, const unsigned char *tbs, size_t tbslen)

{

    PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;

    int ret;

    unsigned int sltmp;

    size_t dsasize = DSA_size(pdsactx->dsa);

    size_t mdsize = dsa_get_md_size(pdsactx);

    if (!ossl_prov_is_running())

        return 0;

    if (sig == NULL) {

        *siglen = dsasize;

        return 1;

    }

    if (sigsize < (size_t)dsasize)

        return 0;

    if (mdsize != 0 && tbslen != mdsize)

        return 0;

    ret = ossl_dsa_sign_int(0, tbs, tbslen, sig, &sltmp, pdsactx->dsa);

    if (ret <= 0)

        return 0;

    *siglen = sltmp;

    return 1;

}

static int dsa_verify(void *vpdsactx, const unsigned char *sig, size_t siglen,

    const unsigned char *tbs, size_t tbslen)

{

    PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;

    size_t mdsize = dsa_get_md_size(pdsactx);

    if (!ossl_prov_is_running() || (mdsize != 0 && tbslen != mdsize))

        return 0;

    return DSA_verify(0, tbs, tbslen, sig, siglen, pdsactx->dsa);

}

static int dsa_digest_signverify_init(void *vpdsactx, const char *mdname,

    void *vdsa, const OSSL_PARAM params[],

    int operation)

{

    PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;

    if (!ossl_prov_is_running())

        return 0;

    if (!dsa_signverify_init(vpdsactx, vdsa, params, operation))

        return 0;

    if (!dsa_setup_md(pdsactx, mdname, NULL))

        return 0;

    pdsactx->flag_allow_md = 0;

    if (pdsactx->mdctx == NULL) {

        pdsactx->mdctx = EVP_MD_CTX_new();

        if (pdsactx->mdctx == NULL)

            goto error;

    }

    if (!EVP_DigestInit_ex2(pdsactx->mdctx, pdsactx->md, params))

        goto error;

    return 1;

error:

    EVP_MD_CTX_free(pdsactx->mdctx);

    pdsactx->mdctx = NULL;

    return 0;

}

static int dsa_digest_sign_init(void *vpdsactx, const char *mdname,

    void *vdsa, const OSSL_PARAM params[])

{

    return dsa_digest_signverify_init(vpdsactx, mdname, vdsa, params,

        EVP_PKEY_OP_SIGN);

}

static int dsa_digest_verify_init(void *vpdsactx, const char *mdname,

    void *vdsa, const OSSL_PARAM params[])

{

    return dsa_digest_signverify_init(vpdsactx, mdname, vdsa, params,

        EVP_PKEY_OP_VERIFY);

}

int dsa_digest_signverify_update(void *vpdsactx, const unsigned char *data,

    size_t datalen)

{

    PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;

    if (pdsactx == NULL || pdsactx->mdctx == NULL)

        return 0;

    return EVP_DigestUpdate(pdsactx->mdctx, data, datalen);

}

int dsa_digest_sign_final(void *vpdsactx, unsigned char *sig, size_t *siglen,

    size_t sigsize)

{

    PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;

    unsigned char digest[EVP_MAX_MD_SIZE];

    unsigned int dlen = 0;

    if (!ossl_prov_is_running() || pdsactx == NULL || pdsactx->mdctx == NULL)

        return 0;

    /*

     * If sig is NULL then we're just finding out the sig size. Other fields

     * are ignored. Defer to dsa_sign.

     */

    if (sig != NULL) {

        /*

         * There is the possibility that some externally provided

         * digests exceed EVP_MAX_MD_SIZE. We should probably handle that somehow -

         * but that problem is much larger than just in DSA.

         */

        if (!EVP_DigestFinal_ex(pdsactx->mdctx, digest, &dlen))

            return 0;

    }

    pdsactx->flag_allow_md = 1;

    return dsa_sign(vpdsactx, sig, siglen, sigsize, digest, (size_t)dlen);

}

int dsa_digest_verify_final(void *vpdsactx, const unsigned char *sig,

    size_t siglen)

{

    PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;

    unsigned char digest[EVP_MAX_MD_SIZE];

    unsigned int dlen = 0;

    if (!ossl_prov_is_running() || pdsactx == NULL || pdsactx->mdctx == NULL)

        return 0;

    /*

     * There is the possibility that some externally provided

     * digests exceed EVP_MAX_MD_SIZE. We should probably handle that somehow -

     * but that problem is much larger than just in DSA.

     */

    if (!EVP_DigestFinal_ex(pdsactx->mdctx, digest, &dlen))

        return 0;

    pdsactx->flag_allow_md = 1;

    return dsa_verify(vpdsactx, sig, siglen, digest, (size_t)dlen);

}

static void dsa_freectx(void *vpdsactx)

{

    PROV_DSA_CTX *ctx = (PROV_DSA_CTX *)vpdsactx;

    OPENSSL_free(ctx->propq);

    EVP_MD_CTX_free(ctx->mdctx);

    EVP_MD_free(ctx->md);

    ctx->propq = NULL;

    ctx->mdctx = NULL;

    ctx->md = NULL;

    DSA_free(ctx->dsa);

    OPENSSL_free(ctx);

}

static void *dsa_dupctx(void *vpdsactx)

{

    PROV_DSA_CTX *srcctx = (PROV_DSA_CTX *)vpdsactx;

    PROV_DSA_CTX *dstctx;

    if (!ossl_prov_is_running())

        return NULL;

    dstctx = OPENSSL_zalloc(sizeof(*srcctx));

    if (dstctx == NULL)

        return NULL;

    *dstctx = *srcctx;

    dstctx->dsa = NULL;

    dstctx->md = NULL;

    dstctx->mdctx = NULL;

    dstctx->propq = NULL;

    dstctx->aid = NULL;

    if (srcctx->dsa != NULL && !DSA_up_ref(srcctx->dsa))

        goto err;

    dstctx->dsa = srcctx->dsa;

    if (srcctx->md != NULL && !EVP_MD_up_ref(srcctx->md))

        goto err;

    dstctx->md = srcctx->md;

    if (srcctx->mdctx != NULL) {

        dstctx->mdctx = EVP_MD_CTX_new();

        if (dstctx->mdctx == NULL

            || !EVP_MD_CTX_copy_ex(dstctx->mdctx, srcctx->mdctx))

            goto err;

    }

    if (srcctx->propq != NULL) {

        dstctx->propq = OPENSSL_strdup(srcctx->propq);

        if (dstctx->propq == NULL)

            goto err;

    }

    /*

     * The DER-encoding of the algorithm OID is written at the end of aid_buf.

     * Check that srcctx->aid points into the source aid_buf and then use the

     * same offset into dstctx->aid_buf.

     */

    if (srcctx->aid != NULL

        && srcctx->aid_len > 0

        && srcctx->aid >= srcctx->aid_buf

        && srcctx->aid + srcctx->aid_len <= srcctx->aid_buf + sizeof(srcctx->aid_buf))

        dstctx->aid = dstctx->aid_buf + (srcctx->aid - srcctx->aid_buf);

    else

        dstctx->aid_len = 0;

    return dstctx;

err:

    dsa_freectx(dstctx);

    return NULL;

}

static int dsa_get_ctx_params(void *vpdsactx, OSSL_PARAM *params)

{

    PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;

    OSSL_PARAM *p;

    if (pdsactx == NULL)

        return 0;

    p = OSSL_PARAM_locate(params, OSSL_SIGNATURE_PARAM_ALGORITHM_ID);

    if (p != NULL

        && !OSSL_PARAM_set_octet_string(p, pdsactx->aid, pdsactx->aid_len))

        return 0;

    p = OSSL_PARAM_locate(params, OSSL_SIGNATURE_PARAM_DIGEST);

    if (p != NULL && !OSSL_PARAM_set_utf8_string(p, pdsactx->mdname))

        return 0;

    return 1;

}

static const OSSL_PARAM known_gettable_ctx_params[] = {

    OSSL_PARAM_octet_string(OSSL_SIGNATURE_PARAM_ALGORITHM_ID, NULL, 0),

    OSSL_PARAM_utf8_string(OSSL_SIGNATURE_PARAM_DIGEST, NULL, 0),

    OSSL_PARAM_END

};

static const OSSL_PARAM *dsa_gettable_ctx_params(ossl_unused void *ctx,

    ossl_unused void *provctx)

{

    return known_gettable_ctx_params;

}

static int dsa_set_ctx_params(void *vpdsactx, const OSSL_PARAM params[])

{

    PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;

    const OSSL_PARAM *p;

    if (pdsactx == NULL)

        return 0;

    if (params == NULL)

        return 1;

    p = OSSL_PARAM_locate_const(params, OSSL_SIGNATURE_PARAM_DIGEST);

    if (p != NULL) {

        char mdname[OSSL_MAX_NAME_SIZE] = "", *pmdname = mdname;

        char mdprops[OSSL_MAX_PROPQUERY_SIZE] = "", *pmdprops = mdprops;

        const OSSL_PARAM *propsp = OSSL_PARAM_locate_const(params,

            OSSL_SIGNATURE_PARAM_PROPERTIES);

        if (!OSSL_PARAM_get_utf8_string(p, &pmdname, sizeof(mdname)))

            return 0;

        if (propsp != NULL

            && !OSSL_PARAM_get_utf8_string(propsp, &pmdprops, sizeof(mdprops)))

            return 0;

        if (!dsa_setup_md(pdsactx, mdname, mdprops))

            return 0;

    }

    return 1;

}

static const OSSL_PARAM settable_ctx_params[] = {

    OSSL_PARAM_utf8_string(OSSL_SIGNATURE_PARAM_DIGEST, NULL, 0),

    OSSL_PARAM_utf8_string(OSSL_SIGNATURE_PARAM_PROPERTIES, NULL, 0),

    OSSL_PARAM_END

};

static const OSSL_PARAM settable_ctx_params_no_digest[] = {

    OSSL_PARAM_END

};

static const OSSL_PARAM *dsa_settable_ctx_params(void *vpdsactx,

    ossl_unused void *provctx)

{

    PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;

    if (pdsactx != NULL && !pdsactx->flag_allow_md)

        return settable_ctx_params_no_digest;

    return settable_ctx_params;

}

static int dsa_get_ctx_md_params(void *vpdsactx, OSSL_PARAM *params)

{

    PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;

    if (pdsactx->mdctx == NULL)

        return 0;

    return EVP_MD_CTX_get_params(pdsactx->mdctx, params);

}

static const OSSL_PARAM *dsa_gettable_ctx_md_params(void *vpdsactx)

{

    PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;

    if (pdsactx->md == NULL)

        return 0;

    return EVP_MD_gettable_ctx_params(pdsactx->md);

}

static int dsa_set_ctx_md_params(void *vpdsactx, const OSSL_PARAM params[])

{

    PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;

    if (pdsactx->mdctx == NULL)

        return 0;

    return EVP_MD_CTX_set_params(pdsactx->mdctx, params);

}

static const OSSL_PARAM *dsa_settable_ctx_md_params(void *vpdsactx)

{

    PROV_DSA_CTX *pdsactx = (PROV_DSA_CTX *)vpdsactx;

    if (pdsactx->md == NULL)

        return 0;

    return EVP_MD_settable_ctx_params(pdsactx->md);

}

const OSSL_DISPATCH ossl_dsa_signature_functions[] = {

    { OSSL_FUNC_SIGNATURE_NEWCTX, (void (*)(void))dsa_newctx },

    { OSSL_FUNC_SIGNATURE_SIGN_INIT, (void (*)(void))dsa_sign_init },

    { OSSL_FUNC_SIGNATURE_SIGN, (void (*)(void))dsa_sign },

    { OSSL_FUNC_SIGNATURE_VERIFY_INIT, (void (*)(void))dsa_verify_init },

    { OSSL_FUNC_SIGNATURE_VERIFY, (void (*)(void))dsa_verify },

    { OSSL_FUNC_SIGNATURE_DIGEST_SIGN_INIT,

        (void (*)(void))dsa_digest_sign_init },

    { OSSL_FUNC_SIGNATURE_DIGEST_SIGN_UPDATE,

        (void (*)(void))dsa_digest_signverify_update },

    { OSSL_FUNC_SIGNATURE_DIGEST_SIGN_FINAL,

        (void (*)(void))dsa_digest_sign_final },

    { OSSL_FUNC_SIGNATURE_DIGEST_VERIFY_INIT,

        (void (*)(void))dsa_digest_verify_init },

    { OSSL_FUNC_SIGNATURE_DIGEST_VERIFY_UPDATE,

        (void (*)(void))dsa_digest_signverify_update },

    { OSSL_FUNC_SIGNATURE_DIGEST_VERIFY_FINAL,

        (void (*)(void))dsa_digest_verify_final },

    { OSSL_FUNC_SIGNATURE_FREECTX, (void (*)(void))dsa_freectx },

    { OSSL_FUNC_SIGNATURE_DUPCTX, (void (*)(void))dsa_dupctx },

    { OSSL_FUNC_SIGNATURE_GET_CTX_PARAMS, (void (*)(void))dsa_get_ctx_params },

    { OSSL_FUNC_SIGNATURE_GETTABLE_CTX_PARAMS,

        (void (*)(void))dsa_gettable_ctx_params },

    { OSSL_FUNC_SIGNATURE_SET_CTX_PARAMS, (void (*)(void))dsa_set_ctx_params },

    { OSSL_FUNC_SIGNATURE_SETTABLE_CTX_PARAMS,

        (void (*)(void))dsa_settable_ctx_params },

    { OSSL_FUNC_SIGNATURE_GET_CTX_MD_PARAMS,

        (void (*)(void))dsa_get_ctx_md_params },

    { OSSL_FUNC_SIGNATURE_GETTABLE_CTX_MD_PARAMS,

        (void (*)(void))dsa_gettable_ctx_md_params },

    { OSSL_FUNC_SIGNATURE_SET_CTX_MD_PARAMS,

        (void (*)(void))dsa_set_ctx_md_params },

    { OSSL_FUNC_SIGNATURE_SETTABLE_CTX_MD_PARAMS,

        (void (*)(void))dsa_settable_ctx_md_params },

    { 0, NULL }

};