/*

 * Copyright 2006-2023 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

 */

#include <stdio.h>

#include "internal/cryptlib.h"

#include <openssl/evp.h>

#include <openssl/objects.h>

#include "crypto/evp.h"

#include "internal/provider.h"

#include "internal/numbers.h"   /* includes SIZE_MAX */

#include "evp_local.h"

#ifndef FIPS_MODULE

static int update(EVP_MD_CTX *ctx, const void *data, size_t datalen)

{

    ERR_raise(ERR_LIB_EVP, EVP_R_ONLY_ONESHOT_SUPPORTED);

    return 0;

}

/*

 * If we get the "NULL" md then the name comes back as "UNDEF". We want to use

 * NULL for this.

 */

static const char *canon_mdname(const char *mdname)

{

    if (mdname != NULL && strcmp(mdname, "UNDEF") == 0)

        return NULL;

    return mdname;

}

static int do_sigver_init(EVP_MD_CTX *ctx, EVP_PKEY_CTX **pctx,

                          const EVP_MD *type, const char *mdname,

                          OSSL_LIB_CTX *libctx, const char *props,

                          ENGINE *e, EVP_PKEY *pkey, int ver,

                          const OSSL_PARAM params[])

{

    EVP_PKEY_CTX *locpctx = NULL;

    EVP_SIGNATURE *signature = NULL;

    EVP_KEYMGMT *tmp_keymgmt = NULL;

    const OSSL_PROVIDER *tmp_prov = NULL;

    const char *supported_sig = NULL;

    char locmdname[80] = "";     /* 80 chars should be enough */

    void *provkey = NULL;

    int ret, iter, reinit = 1;

    if (!evp_md_ctx_free_algctx(ctx))

        return 0;

    if (ctx->pctx == NULL) {

        reinit = 0;

        if (e == NULL)

            ctx->pctx = EVP_PKEY_CTX_new_from_pkey(libctx, pkey, props);

        else

            ctx->pctx = EVP_PKEY_CTX_new(pkey, e);

    }

    if (ctx->pctx == NULL)

        return 0;

    EVP_MD_CTX_clear_flags(ctx, EVP_MD_CTX_FLAG_FINALISED);

    locpctx = ctx->pctx;

    ERR_set_mark();

    if (evp_pkey_ctx_is_legacy(locpctx))

        goto legacy;

    /* do not reinitialize if pkey is set or operation is different */

    if (reinit

        && (pkey != NULL

            || locpctx->operation != (ver ? EVP_PKEY_OP_VERIFYCTX

                                          : EVP_PKEY_OP_SIGNCTX)

            || (signature = locpctx->op.sig.signature) == NULL

            || locpctx->op.sig.algctx == NULL))

        reinit = 0;

    if (props == NULL)

        props = locpctx->propquery;

    if (locpctx->pkey == NULL) {

        ERR_clear_last_mark();

        ERR_raise(ERR_LIB_EVP, EVP_R_NO_KEY_SET);

        goto err;

    }

    if (!reinit) {

        evp_pkey_ctx_free_old_ops(locpctx);

    } else {

        if (mdname == NULL && type == NULL)

            mdname = canon_mdname(EVP_MD_get0_name(ctx->reqdigest));

        goto reinitialize;

    }

    /*

     * Try to derive the supported signature from |locpctx->keymgmt|.

     */

    if (!ossl_assert(locpctx->pkey->keymgmt == NULL

                     || locpctx->pkey->keymgmt == locpctx->keymgmt)) {

        ERR_clear_last_mark();

        ERR_raise(ERR_LIB_EVP, ERR_R_INTERNAL_ERROR);

        goto err;

    }

    supported_sig = evp_keymgmt_util_query_operation_name(locpctx->keymgmt,

                                                          OSSL_OP_SIGNATURE);

    if (supported_sig == NULL) {

        ERR_clear_last_mark();

        ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);

        goto err;

    }

    /*

     * We perform two iterations:

     *

     * 1.  Do the normal signature fetch, using the fetching data given by

     *     the EVP_PKEY_CTX.

     * 2.  Do the provider specific signature fetch, from the same provider

     *     as |ctx->keymgmt|

     *

     * We then try to fetch the keymgmt from the same provider as the

     * signature, and try to export |ctx->pkey| to that keymgmt (when

     * this keymgmt happens to be the same as |ctx->keymgmt|, the export

     * is a no-op, but we call it anyway to not complicate the code even

     * more).

     * If the export call succeeds (returns a non-NULL provider key pointer),

     * we're done and can perform the operation itself.  If not, we perform

     * the second iteration, or jump to legacy.

     */

    for (iter = 1, provkey = NULL; iter < 3 && provkey == NULL; iter++) {

        EVP_KEYMGMT *tmp_keymgmt_tofree = NULL;

        /*

         * If we're on the second iteration, free the results from the first.

         * They are NULL on the first iteration, so no need to check what

         * iteration we're on.

         */

        EVP_SIGNATURE_free(signature);

        EVP_KEYMGMT_free(tmp_keymgmt);

        switch (iter) {

        case 1:

            signature = EVP_SIGNATURE_fetch(locpctx->libctx, supported_sig,

                                            locpctx->propquery);

            if (signature != NULL)

                tmp_prov = EVP_SIGNATURE_get0_provider(signature);

            break;

        case 2:

            tmp_prov = EVP_KEYMGMT_get0_provider(locpctx->keymgmt);

            signature =

                evp_signature_fetch_from_prov((OSSL_PROVIDER *)tmp_prov,

                                              supported_sig, locpctx->propquery);

            if (signature == NULL)

                goto legacy;

            break;

        }

        if (signature == NULL)

            continue;

        /*

         * Ensure that the key is provided, either natively, or as a cached

         * export.  We start by fetching the keymgmt with the same name as

         * |locpctx->pkey|, but from the provider of the signature method, using

         * the same property query as when fetching the signature method.

         * With the keymgmt we found (if we did), we try to export |locpctx->pkey|

         * to it (evp_pkey_export_to_provider() is smart enough to only actually

         * export it if |tmp_keymgmt| is different from |locpctx->pkey|'s keymgmt)

         */

        tmp_keymgmt_tofree = tmp_keymgmt =

            evp_keymgmt_fetch_from_prov((OSSL_PROVIDER *)tmp_prov,

                                        EVP_KEYMGMT_get0_name(locpctx->keymgmt),

                                        locpctx->propquery);

        if (tmp_keymgmt != NULL)

            provkey = evp_pkey_export_to_provider(locpctx->pkey, locpctx->libctx,

                                                  &tmp_keymgmt, locpctx->propquery);

        if (tmp_keymgmt == NULL)

            EVP_KEYMGMT_free(tmp_keymgmt_tofree);

    }

    if (provkey == NULL) {

        EVP_SIGNATURE_free(signature);

        ERR_clear_last_mark();

        ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);

        goto err;

    }

    ERR_pop_to_mark();

    /* No more legacy from here down to legacy: */

    locpctx->op.sig.signature = signature;

    locpctx->operation = ver ? EVP_PKEY_OP_VERIFYCTX

                             : EVP_PKEY_OP_SIGNCTX;

    locpctx->op.sig.algctx

        = signature->newctx(ossl_provider_ctx(signature->prov), props);

    if (locpctx->op.sig.algctx == NULL) {

        ERR_raise(ERR_LIB_EVP,  EVP_R_INITIALIZATION_ERROR);

        goto err;

    }

 reinitialize:

    if (pctx != NULL)

        *pctx = locpctx;

    if (type != NULL) {

        ctx->reqdigest = type;

        if (mdname == NULL)

            mdname = canon_mdname(EVP_MD_get0_name(type));

    } else {

        if (mdname == NULL && !reinit) {

            if (evp_keymgmt_util_get_deflt_digest_name(tmp_keymgmt, provkey,

                                                       locmdname,

                                                       sizeof(locmdname)) > 0) {

                mdname = canon_mdname(locmdname);

            }

        }

        if (mdname != NULL) {

            /*

             * We're about to get a new digest so clear anything associated with

             * an old digest.

             */

            evp_md_ctx_clear_digest(ctx, 1, 0);

            /* legacy code support for engines */

            ERR_set_mark();

            /*

             * This might be requested by a later call to EVP_MD_CTX_get0_md().

             * In that case the "explicit fetch" rules apply for that

             * function (as per man pages), i.e. the ref count is not updated

             * so the EVP_MD should not be used beyond the lifetime of the

             * EVP_MD_CTX.

             */

            ctx->fetched_digest = EVP_MD_fetch(locpctx->libctx, mdname, props);

            if (ctx->fetched_digest != NULL) {

                ctx->digest = ctx->reqdigest = ctx->fetched_digest;

            } else {

                /* legacy engine support : remove the mark when this is deleted */

                ctx->reqdigest = ctx->digest = EVP_get_digestbyname(mdname);

                if (ctx->digest == NULL) {

                    (void)ERR_clear_last_mark();

                    ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);

                    goto err;

                }

            }

            (void)ERR_pop_to_mark();

        }

    }

    if (ver) {

        if (signature->digest_verify_init == NULL) {

            ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);

            goto err;

        }

        ret = signature->digest_verify_init(locpctx->op.sig.algctx,

                                            mdname, provkey, params);

    } else {

        if (signature->digest_sign_init == NULL) {

            ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);

            goto err;

        }

        ret = signature->digest_sign_init(locpctx->op.sig.algctx,

                                          mdname, provkey, params);

    }

    /*

     * If the operation was not a success and no digest was found, an error

     * needs to be raised.

     */

    if (ret > 0 || mdname != NULL)

        goto end;

    if (type == NULL)   /* This check is redundant but clarifies matters */

        ERR_raise(ERR_LIB_EVP, EVP_R_NO_DEFAULT_DIGEST);

 err:

    evp_pkey_ctx_free_old_ops(locpctx);

    locpctx->operation = EVP_PKEY_OP_UNDEFINED;

    EVP_KEYMGMT_free(tmp_keymgmt);

    return 0;

 legacy:

    /*

     * If we don't have the full support we need with provided methods,

     * let's go see if legacy does.

     */

    ERR_pop_to_mark();

    EVP_KEYMGMT_free(tmp_keymgmt);

    tmp_keymgmt = NULL;

    if (type == NULL && mdname != NULL)

        type = evp_get_digestbyname_ex(locpctx->libctx, mdname);

    if (ctx->pctx->pmeth == NULL) {

        ERR_raise(ERR_LIB_EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);

        return 0;

    }

    if (!(ctx->pctx->pmeth->flags & EVP_PKEY_FLAG_SIGCTX_CUSTOM)) {

        if (type == NULL) {

            int def_nid;

            if (EVP_PKEY_get_default_digest_nid(pkey, &def_nid) > 0)

                type = EVP_get_digestbynid(def_nid);

        }

        if (type == NULL) {

            ERR_raise(ERR_LIB_EVP, EVP_R_NO_DEFAULT_DIGEST);

            return 0;

        }

    }

    if (ver) {

        if (ctx->pctx->pmeth->verifyctx_init) {

            if (ctx->pctx->pmeth->verifyctx_init(ctx->pctx, ctx) <= 0)

                return 0;

            ctx->pctx->operation = EVP_PKEY_OP_VERIFYCTX;

        } else if (ctx->pctx->pmeth->digestverify != 0) {

            ctx->pctx->operation = EVP_PKEY_OP_VERIFY;

            ctx->update = update;

        } else if (EVP_PKEY_verify_init(ctx->pctx) <= 0) {

            return 0;

        }

    } else {

        if (ctx->pctx->pmeth->signctx_init) {

            if (ctx->pctx->pmeth->signctx_init(ctx->pctx, ctx) <= 0)

                return 0;

            ctx->pctx->operation = EVP_PKEY_OP_SIGNCTX;

        } else if (ctx->pctx->pmeth->digestsign != 0) {

            ctx->pctx->operation = EVP_PKEY_OP_SIGN;

            ctx->update = update;

        } else if (EVP_PKEY_sign_init(ctx->pctx) <= 0) {

            return 0;

        }

    }

    if (EVP_PKEY_CTX_set_signature_md(ctx->pctx, type) <= 0)

        return 0;

    if (pctx)

        *pctx = ctx->pctx;

    if (ctx->pctx->pmeth->flags & EVP_PKEY_FLAG_SIGCTX_CUSTOM)

        return 1;

    if (!EVP_DigestInit_ex(ctx, type, e))

        return 0;

    /*

     * This indicates the current algorithm requires

     * special treatment before hashing the tbs-message.

     */

    ctx->pctx->flag_call_digest_custom = 0;

    if (ctx->pctx->pmeth->digest_custom != NULL)

        ctx->pctx->flag_call_digest_custom = 1;

    ret = 1;

 end:

#ifndef FIPS_MODULE

    if (ret > 0)

        ret = evp_pkey_ctx_use_cached_data(locpctx);

#endif

    EVP_KEYMGMT_free(tmp_keymgmt);

    return ret > 0 ? 1 : 0;

}

int EVP_DigestSignInit_ex(EVP_MD_CTX *ctx, EVP_PKEY_CTX **pctx,

                          const char *mdname, OSSL_LIB_CTX *libctx,

                          const char *props, EVP_PKEY *pkey,

                          const OSSL_PARAM params[])

{

    return do_sigver_init(ctx, pctx, NULL, mdname, libctx, props, NULL, pkey, 0,

                          params);

}

int EVP_DigestSignInit(EVP_MD_CTX *ctx, EVP_PKEY_CTX **pctx,

                       const EVP_MD *type, ENGINE *e, EVP_PKEY *pkey)

{

    return do_sigver_init(ctx, pctx, type, NULL, NULL, NULL, e, pkey, 0,

                          NULL);

}

int EVP_DigestVerifyInit_ex(EVP_MD_CTX *ctx, EVP_PKEY_CTX **pctx,

                            const char *mdname, OSSL_LIB_CTX *libctx,

                            const char *props, EVP_PKEY *pkey,

                            const OSSL_PARAM params[])

{

    return do_sigver_init(ctx, pctx, NULL, mdname, libctx, props, NULL, pkey, 1,

                          params);

}

int EVP_DigestVerifyInit(EVP_MD_CTX *ctx, EVP_PKEY_CTX **pctx,

                         const EVP_MD *type, ENGINE *e, EVP_PKEY *pkey)

{

    return do_sigver_init(ctx, pctx, type, NULL, NULL, NULL, e, pkey, 1,

                          NULL);

}

#endif /* FIPS_MDOE */

int EVP_DigestSignUpdate(EVP_MD_CTX *ctx, const void *data, size_t dsize)

{

    EVP_PKEY_CTX *pctx = ctx->pctx;

    if ((ctx->flags & EVP_MD_CTX_FLAG_FINALISED) != 0) {

        ERR_raise(ERR_LIB_EVP, EVP_R_UPDATE_ERROR);

        return 0;

    }

    if (pctx == NULL

            || pctx->operation != EVP_PKEY_OP_SIGNCTX

            || pctx->op.sig.algctx == NULL

            || pctx->op.sig.signature == NULL)

        goto legacy;

    if (pctx->op.sig.signature->digest_sign_update == NULL) {

        ERR_raise(ERR_LIB_EVP, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);

        return 0;

    }

    return pctx->op.sig.signature->digest_sign_update(pctx->op.sig.algctx,

                                                      data, dsize);

 legacy:

    if (pctx != NULL) {

        /* do_sigver_init() checked that |digest_custom| is non-NULL */

        if (pctx->flag_call_digest_custom

            && !ctx->pctx->pmeth->digest_custom(ctx->pctx, ctx))

            return 0;

        pctx->flag_call_digest_custom = 0;

    }

    return EVP_DigestUpdate(ctx, data, dsize);

}

int EVP_DigestVerifyUpdate(EVP_MD_CTX *ctx, const void *data, size_t dsize)

{

    EVP_PKEY_CTX *pctx = ctx->pctx;

    if ((ctx->flags & EVP_MD_CTX_FLAG_FINALISED) != 0) {

        ERR_raise(ERR_LIB_EVP, EVP_R_UPDATE_ERROR);

        return 0;

    }

    if (pctx == NULL

            || pctx->operation != EVP_PKEY_OP_VERIFYCTX

            || pctx->op.sig.algctx == NULL

            || pctx->op.sig.signature == NULL)

        goto legacy;

    if (pctx->op.sig.signature->digest_verify_update == NULL) {

        ERR_raise(ERR_LIB_EVP, ERR_R_SHOULD_NOT_HAVE_BEEN_CALLED);

        return 0;

    }

    return pctx->op.sig.signature->digest_verify_update(pctx->op.sig.algctx,

                                                        data, dsize);

 legacy:

    if (pctx != NULL) {

        /* do_sigver_init() checked that |digest_custom| is non-NULL */

        if (pctx->flag_call_digest_custom

            && !ctx->pctx->pmeth->digest_custom(ctx->pctx, ctx))

            return 0;

        pctx->flag_call_digest_custom = 0;

    }

    return EVP_DigestUpdate(ctx, data, dsize);

}

#ifndef FIPS_MODULE

int EVP_DigestSignFinal(EVP_MD_CTX *ctx, unsigned char *sigret,

                        size_t *siglen)

{

    int sctx = 0, r = 0;

    EVP_PKEY_CTX *dctx = NULL, *pctx = ctx->pctx;

    if ((ctx->flags & EVP_MD_CTX_FLAG_FINALISED) != 0) {

        ERR_raise(ERR_LIB_EVP, EVP_R_FINAL_ERROR);

        return 0;

    }

    if (pctx == NULL

            || pctx->operation != EVP_PKEY_OP_SIGNCTX

            || pctx->op.sig.algctx == NULL

            || pctx->op.sig.signature == NULL)

        goto legacy;

    if (sigret != NULL && (ctx->flags & EVP_MD_CTX_FLAG_FINALISE) == 0) {

        /* try dup */

        dctx = EVP_PKEY_CTX_dup(pctx);

        if (dctx != NULL)

            pctx = dctx;

    }

    r = pctx->op.sig.signature->digest_sign_final(pctx->op.sig.algctx,

                                                  sigret, siglen,

                                                  sigret == NULL ? 0 : *siglen);

    if (dctx == NULL && sigret != NULL)

        ctx->flags |= EVP_MD_CTX_FLAG_FINALISED;

    else

        EVP_PKEY_CTX_free(dctx);

    return r;

 legacy:

    if (pctx == NULL || pctx->pmeth == NULL) {

        ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);

        return 0;

    }

    /* do_sigver_init() checked that |digest_custom| is non-NULL */

    if (pctx->flag_call_digest_custom

        && !ctx->pctx->pmeth->digest_custom(ctx->pctx, ctx))

        return 0;

    pctx->flag_call_digest_custom = 0;

    if (pctx->pmeth->flags & EVP_PKEY_FLAG_SIGCTX_CUSTOM) {

        if (sigret == NULL)

            return pctx->pmeth->signctx(pctx, sigret, siglen, ctx);

        if ((ctx->flags & EVP_MD_CTX_FLAG_FINALISE) != 0) {

            r = pctx->pmeth->signctx(pctx, sigret, siglen, ctx);

            ctx->flags |= EVP_MD_CTX_FLAG_FINALISED;

        } else {

            dctx = EVP_PKEY_CTX_dup(pctx);

            if (dctx == NULL)

                return 0;

            r = dctx->pmeth->signctx(dctx, sigret, siglen, ctx);

            EVP_PKEY_CTX_free(dctx);

        }

        return r;

    }

    if (pctx->pmeth->signctx != NULL)

        sctx = 1;

    else

        sctx = 0;

    if (sigret != NULL) {

        unsigned char md[EVP_MAX_MD_SIZE];

        unsigned int mdlen = 0;

        if (ctx->flags & EVP_MD_CTX_FLAG_FINALISE) {

            if (sctx)

                r = pctx->pmeth->signctx(pctx, sigret, siglen, ctx);

            else

                r = EVP_DigestFinal_ex(ctx, md, &mdlen);

        } else {

            EVP_MD_CTX *tmp_ctx = EVP_MD_CTX_new();

            if (tmp_ctx == NULL)

                return 0;

            if (!EVP_MD_CTX_copy_ex(tmp_ctx, ctx)) {

                EVP_MD_CTX_free(tmp_ctx);

                return 0;

            }

            if (sctx)

                r = tmp_ctx->pctx->pmeth->signctx(tmp_ctx->pctx,

                                                  sigret, siglen, tmp_ctx);

            else

                r = EVP_DigestFinal_ex(tmp_ctx, md, &mdlen);

            EVP_MD_CTX_free(tmp_ctx);

        }

        if (sctx || !r)

            return r;

        if (EVP_PKEY_sign(pctx, sigret, siglen, md, mdlen) <= 0)

            return 0;

    } else {

        if (sctx) {

            if (pctx->pmeth->signctx(pctx, sigret, siglen, ctx) <= 0)

                return 0;

        } else {

            int s = EVP_MD_get_size(ctx->digest);

            if (s < 0 || EVP_PKEY_sign(pctx, sigret, siglen, NULL, s) <= 0)

                return 0;

        }

    }

    return 1;

}

int EVP_DigestSign(EVP_MD_CTX *ctx, unsigned char *sigret, size_t *siglen,

                   const unsigned char *tbs, size_t tbslen)

{

    EVP_PKEY_CTX *pctx = ctx->pctx;

    if ((ctx->flags & EVP_MD_CTX_FLAG_FINALISED) != 0) {

        ERR_raise(ERR_LIB_EVP, EVP_R_FINAL_ERROR);

        return 0;

    }

    if (pctx != NULL

            && pctx->operation == EVP_PKEY_OP_SIGNCTX

            && pctx->op.sig.algctx != NULL

            && pctx->op.sig.signature != NULL) {

        if (pctx->op.sig.signature->digest_sign != NULL) {

            if (sigret != NULL)

                ctx->flags |= EVP_MD_CTX_FLAG_FINALISED;

            return pctx->op.sig.signature->digest_sign(pctx->op.sig.algctx,

                                                       sigret, siglen,

                                                       sigret == NULL ? 0 : *siglen,

                                                       tbs, tbslen);

        }

    } else {

        /* legacy */

        if (ctx->pctx->pmeth != NULL && ctx->pctx->pmeth->digestsign != NULL)

            return ctx->pctx->pmeth->digestsign(ctx, sigret, siglen, tbs, tbslen);

    }

    if (sigret != NULL && EVP_DigestSignUpdate(ctx, tbs, tbslen) <= 0)

        return 0;

    return EVP_DigestSignFinal(ctx, sigret, siglen);

}

int EVP_DigestVerifyFinal(EVP_MD_CTX *ctx, const unsigned char *sig,

                          size_t siglen)

{

    unsigned char md[EVP_MAX_MD_SIZE];

    int r = 0;

    unsigned int mdlen = 0;

    int vctx = 0;

    EVP_PKEY_CTX *dctx = NULL, *pctx = ctx->pctx;

    if ((ctx->flags & EVP_MD_CTX_FLAG_FINALISED) != 0) {

        ERR_raise(ERR_LIB_EVP, EVP_R_FINAL_ERROR);

        return 0;

    }

    if (pctx == NULL

            || pctx->operation != EVP_PKEY_OP_VERIFYCTX

            || pctx->op.sig.algctx == NULL

            || pctx->op.sig.signature == NULL)

        goto legacy;

    if ((ctx->flags & EVP_MD_CTX_FLAG_FINALISE) == 0) {

        /* try dup */

        dctx = EVP_PKEY_CTX_dup(pctx);

        if (dctx != NULL)

            pctx = dctx;

    }

    r = pctx->op.sig.signature->digest_verify_final(pctx->op.sig.algctx,

                                                    sig, siglen);

    if (dctx == NULL)

        ctx->flags |= EVP_MD_CTX_FLAG_FINALISED;

    else

        EVP_PKEY_CTX_free(dctx);

    return r;

 legacy:

    if (pctx == NULL || pctx->pmeth == NULL) {

        ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);

        return 0;

    }

    /* do_sigver_init() checked that |digest_custom| is non-NULL */

    if (pctx->flag_call_digest_custom

        && !ctx->pctx->pmeth->digest_custom(ctx->pctx, ctx))

        return 0;

    pctx->flag_call_digest_custom = 0;

    if (pctx->pmeth->verifyctx != NULL)

        vctx = 1;

    else

        vctx = 0;

    if (ctx->flags & EVP_MD_CTX_FLAG_FINALISE) {

        if (vctx) {

            r = pctx->pmeth->verifyctx(pctx, sig, siglen, ctx);

            ctx->flags |= EVP_MD_CTX_FLAG_FINALISED;

        } else

            r = EVP_DigestFinal_ex(ctx, md, &mdlen);

    } else {

        EVP_MD_CTX *tmp_ctx = EVP_MD_CTX_new();

        if (tmp_ctx == NULL)

            return -1;

        if (!EVP_MD_CTX_copy_ex(tmp_ctx, ctx)) {

            EVP_MD_CTX_free(tmp_ctx);

            return -1;

        }

        if (vctx)

            r = tmp_ctx->pctx->pmeth->verifyctx(tmp_ctx->pctx,

                                                sig, siglen, tmp_ctx);

        else

            r = EVP_DigestFinal_ex(tmp_ctx, md, &mdlen);

        EVP_MD_CTX_free(tmp_ctx);

    }

    if (vctx || !r)

        return r;

    return EVP_PKEY_verify(pctx, sig, siglen, md, mdlen);

}

int EVP_DigestVerify(EVP_MD_CTX *ctx, const unsigned char *sigret,

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

{

    EVP_PKEY_CTX *pctx = ctx->pctx;

    if (pctx == NULL) {

        ERR_raise(ERR_LIB_EVP, EVP_R_INITIALIZATION_ERROR);

        return -1;

    }

    if ((ctx->flags & EVP_MD_CTX_FLAG_FINALISED) != 0) {

        ERR_raise(ERR_LIB_EVP, EVP_R_FINAL_ERROR);

        return 0;

    }

    if (pctx->operation == EVP_PKEY_OP_VERIFYCTX

            && pctx->op.sig.algctx != NULL

            && pctx->op.sig.signature != NULL) {

        if (pctx->op.sig.signature->digest_verify != NULL) {

            ctx->flags |= EVP_MD_CTX_FLAG_FINALISED;

            return pctx->op.sig.signature->digest_verify(pctx->op.sig.algctx,

                                                         sigret, siglen,

                                                         tbs, tbslen);

        }

    } else {

        /* legacy */

        if (pctx->pmeth != NULL && pctx->pmeth->digestverify != NULL)

            return pctx->pmeth->digestverify(ctx, sigret, siglen, tbs, tbslen);

    }

    if (EVP_DigestVerifyUpdate(ctx, tbs, tbslen) <= 0)

        return -1;

    return EVP_DigestVerifyFinal(ctx, sigret, siglen);

}

#endif /* FIPS_MODULE */