/*

 * Copyright 1995-2016 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

 */

/* for secure_getenv */

#define _GNU_SOURCE

#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"

#ifndef NO_ASN1_OLD

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();

    const EVP_MD *type;

    unsigned char *p, *buf_in = NULL;

    int ret = -1, i, inl;

    if (ctx == NULL) {

        ASN1err(ASN1_F_ASN1_VERIFY, ERR_R_MALLOC_FAILURE);

        goto err;

    }

    i = OBJ_obj2nid(a->algorithm);

    type = EVP_get_digestbyname(OBJ_nid2sn(i));

    if (type == NULL) {

        ASN1err(ASN1_F_ASN1_VERIFY, ASN1_R_UNKNOWN_MESSAGE_DIGEST_ALGORITHM);

        goto err;

    }

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

        ASN1err(ASN1_F_ASN1_VERIFY, ASN1_R_INVALID_BIT_STRING_BITS_LEFT);

        goto err;

    }

    inl = i2d(data, NULL);

    if (inl <= 0) {

        ASN1err(ASN1_F_ASN1_VERIFY, ERR_R_INTERNAL_ERROR);

        goto err;

    }

    buf_in = OPENSSL_malloc((unsigned int)inl);

    if (buf_in == NULL) {

        ASN1err(ASN1_F_ASN1_VERIFY, ERR_R_MALLOC_FAILURE);

        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) {

        ASN1err(ASN1_F_ASN1_VERIFY, ERR_R_EVP_LIB);

        goto err;

    }

    ret = -1;

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

                        (unsigned int)signature->length, pkey) <= 0) {

        ASN1err(ASN1_F_ASN1_VERIFY, ERR_R_EVP_LIB);

        ret = 0;

        goto err;

    }

    ret = 1;

 err:

    EVP_MD_CTX_free(ctx);

    return ret;

}

#endif

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

                     ASN1_BIT_STRING *signature, void *asn, EVP_PKEY *pkey)

{

    EVP_MD_CTX *ctx = NULL;

    unsigned char *buf_in = NULL;

    int ret = -1, inl = 0;

    int mdnid, pknid;

    size_t inll = 0;

    if (!pkey) {

        ASN1err(ASN1_F_ASN1_ITEM_VERIFY, ERR_R_PASSED_NULL_PARAMETER);

        return -1;

    }

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

        ASN1err(ASN1_F_ASN1_ITEM_VERIFY, ASN1_R_INVALID_BIT_STRING_BITS_LEFT);

        return -1;

    }

    ctx = EVP_MD_CTX_new();

    if (ctx == NULL) {

        ASN1err(ASN1_F_ASN1_ITEM_VERIFY, ERR_R_MALLOC_FAILURE);

        goto err;

    }

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

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

        ASN1err(ASN1_F_ASN1_ITEM_VERIFY, ASN1_R_UNKNOWN_SIGNATURE_ALGORITHM);

        goto err;

    }

    if (mdnid == NID_undef) {

        if (!pkey->ameth || !pkey->ameth->item_verify) {

            ASN1err(ASN1_F_ASN1_ITEM_VERIFY,

                    ASN1_R_UNKNOWN_SIGNATURE_ALGORITHM);

            goto err;

        }

        ret = pkey->ameth->item_verify(ctx, it, asn, a, signature, pkey);

        /*

         * Return value of 2 means carry on, anything else means we exit

         * straight away: either a fatal error of the underlying verification

         * routine handles all verification.

         */

        if (ret != 2)

            goto err;

        ret = -1;

    } else if ((mdnid == NID_md5

               && secure_getenv("OPENSSL_ENABLE_MD5_VERIFY") == NULL) ||

               mdnid == NID_md4 || mdnid == NID_md2 || mdnid == NID_sha) {

        ASN1err(ASN1_F_ASN1_ITEM_VERIFY,

                ASN1_R_UNKNOWN_MESSAGE_DIGEST_ALGORITHM);

        goto err;

    } else {

        const EVP_MD *type = EVP_get_digestbynid(mdnid);

        if (type == NULL) {

            ASN1err(ASN1_F_ASN1_ITEM_VERIFY,

                    ASN1_R_UNKNOWN_MESSAGE_DIGEST_ALGORITHM);

            goto err;

        }

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

        if (EVP_PKEY_type(pknid) != pkey->ameth->pkey_id) {

            ASN1err(ASN1_F_ASN1_ITEM_VERIFY, ASN1_R_WRONG_PUBLIC_KEY_TYPE);

            goto err;

        }

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

            ASN1err(ASN1_F_ASN1_ITEM_VERIFY, ERR_R_EVP_LIB);

            ret = 0;

            goto err;

        }

    }

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

    if (inl <= 0) {

        ASN1err(ASN1_F_ASN1_ITEM_VERIFY, ERR_R_INTERNAL_ERROR);

        goto err;

    }

    if (buf_in == NULL) {

        ASN1err(ASN1_F_ASN1_ITEM_VERIFY, ERR_R_MALLOC_FAILURE);

        goto err;

    }

    inll = inl;

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

                           buf_in, inl);

    if (ret <= 0) {

        ASN1err(ASN1_F_ASN1_ITEM_VERIFY, ERR_R_EVP_LIB);

        goto err;

    }

    ret = 1;

 err:

    OPENSSL_clear_free(buf_in, inll);

    EVP_MD_CTX_free(ctx);

    return ret;

}