/*

 * Copyright 1995-2026 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 <time.h>

#include <sys/types.h>

#include "internal/cryptlib.h"

#include <openssl/bn.h>

#include <openssl/x509.h>

#include <openssl/objects.h>

#include <openssl/buffer.h>

#include <openssl/evp.h>

#include "crypto/asn1.h"

#include "crypto/evp.h"

#include "crypto/rsa.h"

#ifndef OPENSSL_NO_DEPRECATED_3_0

int ASN1_verify(i2d_of_void *i2d, X509_ALGOR *a, ASN1_BIT_STRING *signature,

    char *data, EVP_PKEY *pkey)

{

    EVP_MD_CTX *ctx = EVP_MD_CTX_new();

    EVP_MD *type = NULL;

    unsigned char *p, *buf_in = NULL;

    int ret = -1, i, inl;

    if (ctx == NULL) {

        ERR_raise(ERR_LIB_ASN1, ERR_R_EVP_LIB);

        goto err;

    }

    i = OBJ_obj2nid(a->algorithm);

    type = EVP_MD_fetch(NULL, OBJ_nid2sn(i), NULL);

    if (type == NULL) {

        ERR_raise(ERR_LIB_ASN1, ASN1_R_UNKNOWN_MESSAGE_DIGEST_ALGORITHM);

        goto err;

    }

    if (signature->type == V_ASN1_BIT_STRING && signature->flags & 0x7) {

        ERR_raise(ERR_LIB_ASN1, ASN1_R_INVALID_BIT_STRING_BITS_LEFT);

        goto err;

    }

    inl = i2d(data, NULL);

    if (inl <= 0) {

        ERR_raise(ERR_LIB_ASN1, ERR_R_INTERNAL_ERROR);

        goto err;

    }

    buf_in = OPENSSL_malloc((unsigned int)inl);

    if (buf_in == NULL)

        goto err;

    p = buf_in;

    i2d(data, &p);

    ret = EVP_VerifyInit_ex(ctx, type, NULL)

        && EVP_VerifyUpdate(ctx, (unsigned char *)buf_in, inl);

    OPENSSL_clear_free(buf_in, (unsigned int)inl);

    if (!ret) {

        ERR_raise(ERR_LIB_ASN1, ERR_R_EVP_LIB);

        goto err;

    }

    ret = -1;

    if (EVP_VerifyFinal(ctx, (unsigned char *)signature->data,

            (unsigned int)signature->length, pkey)

        <= 0) {

        ERR_raise(ERR_LIB_ASN1, ERR_R_EVP_LIB);

        ret = 0;

        goto err;

    }

    ret = 1;

err:

    EVP_MD_free(type);

    EVP_MD_CTX_free(ctx);

    return ret;

}

#endif

static int item_verify(const ASN1_ITEM *it, const X509_ALGOR *alg,

    const ASN1_BIT_STRING *signature, const void *data,

    EVP_MD_CTX *ctx, OSSL_LIB_CTX *libctx, const char *propq)

{

    EVP_PKEY_CTX *pctx;

    EVP_PKEY *pkey;

    EVP_MD *type = NULL;

    unsigned char *buf_in = NULL;

    int ret = -1, inl = 0;

    int mdnid, pknid;

    size_t inll = 0;

    pctx = EVP_MD_CTX_get_pkey_ctx(ctx);

    if (pctx == NULL) {

        ERR_raise(ERR_LIB_ASN1, ASN1_R_CONTEXT_NOT_INITIALISED);

        return -1;

    }

    pkey = EVP_PKEY_CTX_get0_pkey(pctx);

    if (pkey == NULL) {

        ERR_raise(ERR_LIB_ASN1, ERR_R_PASSED_NULL_PARAMETER);

        return -1;

    }

    if (signature->type == V_ASN1_BIT_STRING && signature->flags & 0x7) {

        ERR_raise(ERR_LIB_ASN1, ASN1_R_INVALID_BIT_STRING_BITS_LEFT);

        return -1;

    }

    /* Convert signature OID into digest and public key OIDs */

    if (!OBJ_find_sigid_algs(OBJ_obj2nid(alg->algorithm), &mdnid, &pknid)) {

        ERR_raise(ERR_LIB_ASN1, ASN1_R_UNKNOWN_SIGNATURE_ALGORITHM);

        goto err;

    }

    if (mdnid == NID_undef && evp_pkey_is_legacy(pkey)) {

        if (pkey->ameth == NULL || pkey->ameth->item_verify == NULL) {

            ERR_raise(ERR_LIB_ASN1, ASN1_R_UNKNOWN_SIGNATURE_ALGORITHM);

            goto err;

        }

        ret = pkey->ameth->item_verify(ctx, it, data, alg, signature, pkey);

        /*

         * Return values meaning:

         * <=0: error.

         *   1: method does everything.

         *   2: carry on as normal, method has called EVP_DigestVerifyInit()

         */

        if (ret <= 0)

            ERR_raise(ERR_LIB_ASN1, ERR_R_EVP_LIB);

        if (ret <= 1)

            goto err;

    } else {

        /*

         * We don't yet have the ability for providers to be able to handle

         * X509_ALGOR style parameters. Fortunately the only one that needs this

         * so far is RSA-PSS, so we just special case this for now. In some

         * future version of OpenSSL we should push this to the provider.

         */

        if (mdnid == NID_undef && pknid == EVP_PKEY_RSA_PSS) {

            if (!EVP_PKEY_is_a(pkey, "RSA") && !EVP_PKEY_is_a(pkey, "RSA-PSS")) {

                ERR_raise(ERR_LIB_ASN1, ASN1_R_WRONG_PUBLIC_KEY_TYPE);

                goto err;

            }

            /* This function also calls EVP_DigestVerifyInit */

            if (ossl_rsa_pss_to_ctx(ctx, NULL, alg, pkey) <= 0) {

                ERR_raise(ERR_LIB_ASN1, ERR_R_INTERNAL_ERROR);

                goto err;

            }

        } else {

            /* Check public key OID matches public key type */

            if (!EVP_PKEY_is_a(pkey, OBJ_nid2sn(pknid))) {

                ERR_raise(ERR_LIB_ASN1, ASN1_R_WRONG_PUBLIC_KEY_TYPE);

                goto err;

            }

            if (mdnid != NID_undef) {

                type = EVP_MD_fetch(libctx, OBJ_nid2sn(mdnid), propq);

                if (type == NULL) {

                    ERR_raise_data(ERR_LIB_ASN1,

                        ASN1_R_UNKNOWN_MESSAGE_DIGEST_ALGORITHM,

                        "nid=0x%x", mdnid);

                    goto err;

                }

            }

            /*

             * Note that some algorithms (notably Ed25519 and Ed448) may allow

             * a NULL digest value.

             */

            if (!EVP_DigestVerifyInit(ctx, NULL, type, NULL, pkey)) {

                ERR_raise(ERR_LIB_ASN1, ERR_R_EVP_LIB);

                ret = 0;

                goto err;

            }

        }

    }

    inl = ASN1_item_i2d(data, &buf_in, it);

    if (inl <= 0) {

        ERR_raise(ERR_LIB_ASN1, ERR_R_INTERNAL_ERROR);

        ret = -1;

        goto err;

    }

    if (buf_in == NULL) {

        ERR_raise(ERR_LIB_ASN1, ERR_R_ASN1_LIB);

        ret = -1;

        goto err;

    }

    inll = inl;

    ret = EVP_DigestVerify(ctx, signature->data, (size_t)signature->length,

        buf_in, inl);

    if (ret <= 0) {

        ERR_raise(ERR_LIB_ASN1, ERR_R_EVP_LIB);

        goto err;

    }

    ret = 1;

err:

    EVP_MD_free(type);

    OPENSSL_clear_free(buf_in, inll);

    return ret;

}

int ASN1_item_verify(const ASN1_ITEM *it, const X509_ALGOR *alg,

    const ASN1_BIT_STRING *signature, const void *data,

    EVP_PKEY *pkey)

{

    return ASN1_item_verify_ex(it, alg, signature, data, NULL, pkey, NULL, NULL);

}

int ASN1_item_verify_ex(const ASN1_ITEM *it, const X509_ALGOR *alg,

    const ASN1_BIT_STRING *signature, const void *data,

    const ASN1_OCTET_STRING *id, EVP_PKEY *pkey,

    OSSL_LIB_CTX *libctx, const char *propq)

{

    EVP_MD_CTX *ctx;

    int rv = -1;

    if ((ctx = evp_md_ctx_new_ex(pkey, id, libctx, propq)) != NULL) {

        rv = item_verify(it, alg, signature, data, ctx, libctx, propq);

        EVP_PKEY_CTX_free(EVP_MD_CTX_get_pkey_ctx(ctx));

        EVP_MD_CTX_free(ctx);

    }

    return rv;

}

int ASN1_item_verify_ctx(const ASN1_ITEM *it, const X509_ALGOR *alg,

    const ASN1_BIT_STRING *signature, const void *data,

    EVP_MD_CTX *ctx)

{

    return item_verify(it, alg, signature, data, ctx, NULL, NULL);

}