/*

 * Copyright 2009-2018 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 "internal/cryptlib.h"

#include <openssl/asn1t.h>

#include <openssl/pem.h>

#include <openssl/x509v3.h>

#include <openssl/err.h>

#include <openssl/cms.h>

#include <openssl/rand.h>

#include <openssl/aes.h>

#include "cms_local.h"

#include "crypto/asn1.h"

int CMS_RecipientInfo_set0_password(CMS_RecipientInfo *ri,

                                    unsigned char *pass, ossl_ssize_t passlen)

{

    CMS_PasswordRecipientInfo *pwri;

    if (ri->type != CMS_RECIPINFO_PASS) {

        CMSerr(CMS_F_CMS_RECIPIENTINFO_SET0_PASSWORD, CMS_R_NOT_PWRI);

        return 0;

    }

    pwri = ri->d.pwri;

    pwri->pass = pass;

    if (pass && passlen < 0)

        passlen = strlen((char *)pass);

    pwri->passlen = passlen;

    return 1;

}

CMS_RecipientInfo *CMS_add0_recipient_password(CMS_ContentInfo *cms,

                                               int iter, int wrap_nid,

                                               int pbe_nid,

                                               unsigned char *pass,

                                               ossl_ssize_t passlen,

                                               const EVP_CIPHER *kekciph)

{

    CMS_RecipientInfo *ri = NULL;

    CMS_EnvelopedData *env;

    CMS_PasswordRecipientInfo *pwri;

    EVP_CIPHER_CTX *ctx = NULL;

    X509_ALGOR *encalg = NULL;

    unsigned char iv[EVP_MAX_IV_LENGTH];

    int ivlen;

    env = cms_get0_enveloped(cms);

    if (!env)

        return NULL;

    if (wrap_nid <= 0)

        wrap_nid = NID_id_alg_PWRI_KEK;

    if (pbe_nid <= 0)

        pbe_nid = NID_id_pbkdf2;

    /* Get from enveloped data */

    if (kekciph == NULL)

        kekciph = env->encryptedContentInfo->cipher;

    if (kekciph == NULL) {

        CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD, CMS_R_NO_CIPHER);

        return NULL;

    }

    if (wrap_nid != NID_id_alg_PWRI_KEK) {

        CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD,

               CMS_R_UNSUPPORTED_KEY_ENCRYPTION_ALGORITHM);

        return NULL;

    }

    /* Setup algorithm identifier for cipher */

    encalg = X509_ALGOR_new();

    if (encalg == NULL) {

        goto merr;

    }

    ctx = EVP_CIPHER_CTX_new();

    if (EVP_EncryptInit_ex(ctx, kekciph, NULL, NULL, NULL) <= 0) {

        CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD, ERR_R_EVP_LIB);

        goto err;

    }

    ivlen = EVP_CIPHER_CTX_iv_length(ctx);

    if (ivlen > 0) {

        if (RAND_bytes(iv, ivlen) <= 0)

            goto err;

        if (EVP_EncryptInit_ex(ctx, NULL, NULL, NULL, iv) <= 0) {

            CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD, ERR_R_EVP_LIB);

            goto err;

        }

        encalg->parameter = ASN1_TYPE_new();

        if (!encalg->parameter) {

            CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD, ERR_R_MALLOC_FAILURE);

            goto err;

        }

        if (EVP_CIPHER_param_to_asn1(ctx, encalg->parameter) <= 0) {

            CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD,

                   CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);

            goto err;

        }

    }

    encalg->algorithm = OBJ_nid2obj(EVP_CIPHER_CTX_type(ctx));

    EVP_CIPHER_CTX_free(ctx);

    ctx = NULL;

    /* Initialize recipient info */

    ri = M_ASN1_new_of(CMS_RecipientInfo);

    if (ri == NULL)

        goto merr;

    ri->d.pwri = M_ASN1_new_of(CMS_PasswordRecipientInfo);

    if (ri->d.pwri == NULL)

        goto merr;

    ri->type = CMS_RECIPINFO_PASS;

    pwri = ri->d.pwri;

    /* Since this is overwritten, free up empty structure already there */

    X509_ALGOR_free(pwri->keyEncryptionAlgorithm);

    pwri->keyEncryptionAlgorithm = X509_ALGOR_new();

    if (pwri->keyEncryptionAlgorithm == NULL)

        goto merr;

    pwri->keyEncryptionAlgorithm->algorithm = OBJ_nid2obj(wrap_nid);

    pwri->keyEncryptionAlgorithm->parameter = ASN1_TYPE_new();

    if (pwri->keyEncryptionAlgorithm->parameter == NULL)

        goto merr;

    if (!ASN1_item_pack(encalg, ASN1_ITEM_rptr(X509_ALGOR),

                        &pwri->keyEncryptionAlgorithm->parameter->

                        value.sequence))

         goto merr;

    pwri->keyEncryptionAlgorithm->parameter->type = V_ASN1_SEQUENCE;

    X509_ALGOR_free(encalg);

    encalg = NULL;

    /* Setup PBE algorithm */

    pwri->keyDerivationAlgorithm = PKCS5_pbkdf2_set(iter, NULL, 0, -1, -1);

    if (!pwri->keyDerivationAlgorithm)

        goto err;

    CMS_RecipientInfo_set0_password(ri, pass, passlen);

    pwri->version = 0;

    if (!sk_CMS_RecipientInfo_push(env->recipientInfos, ri))

        goto merr;

    return ri;

 merr:

    CMSerr(CMS_F_CMS_ADD0_RECIPIENT_PASSWORD, ERR_R_MALLOC_FAILURE);

 err:

    EVP_CIPHER_CTX_free(ctx);

    if (ri)

        M_ASN1_free_of(ri, CMS_RecipientInfo);

    X509_ALGOR_free(encalg);

    return NULL;

}

/*

 * This is an implementation of the key wrapping mechanism in RFC3211, at

 * some point this should go into EVP.

 */

static int kek_unwrap_key(unsigned char *out, size_t *outlen,

                          const unsigned char *in, size_t inlen,

                          EVP_CIPHER_CTX *ctx)

{

    size_t blocklen = EVP_CIPHER_CTX_block_size(ctx);

    unsigned char *tmp;

    int outl, rv = 0;

    if (inlen < 2 * blocklen) {

        /* too small */

        return 0;

    }

    if (inlen % blocklen) {

        /* Invalid size */

        return 0;

    }

    if ((tmp = OPENSSL_malloc(inlen)) == NULL) {

        CMSerr(CMS_F_KEK_UNWRAP_KEY, ERR_R_MALLOC_FAILURE);

        return 0;

    }

    /* setup IV by decrypting last two blocks */

    if (!EVP_DecryptUpdate(ctx, tmp + inlen - 2 * blocklen, &outl,

                           in + inlen - 2 * blocklen, blocklen * 2)

        /*

         * Do a decrypt of last decrypted block to set IV to correct value

         * output it to start of buffer so we don't corrupt decrypted block

         * this works because buffer is at least two block lengths long.

         */

        || !EVP_DecryptUpdate(ctx, tmp, &outl,

                              tmp + inlen - blocklen, blocklen)

        /* Can now decrypt first n - 1 blocks */

        || !EVP_DecryptUpdate(ctx, tmp, &outl, in, inlen - blocklen)

        /* Reset IV to original value */

        || !EVP_DecryptInit_ex(ctx, NULL, NULL, NULL, NULL)

        /* Decrypt again */

        || !EVP_DecryptUpdate(ctx, tmp, &outl, tmp, inlen))

        goto err;

    /* Check check bytes */

    if (((tmp[1] ^ tmp[4]) & (tmp[2] ^ tmp[5]) & (tmp[3] ^ tmp[6])) != 0xff) {

        /* Check byte failure */

        goto err;

    }

    if (inlen < (size_t)(tmp[0] - 4)) {

        /* Invalid length value */

        goto err;

    }

    *outlen = (size_t)tmp[0];

    memcpy(out, tmp + 4, *outlen);

    rv = 1;

 err:

    OPENSSL_clear_free(tmp, inlen);

    return rv;

}

static int kek_wrap_key(unsigned char *out, size_t *outlen,

                        const unsigned char *in, size_t inlen,

                        EVP_CIPHER_CTX *ctx)

{

    size_t blocklen = EVP_CIPHER_CTX_block_size(ctx);

    size_t olen;

    int dummy;

    /*

     * First decide length of output buffer: need header and round up to

     * multiple of block length.

     */

    olen = (inlen + 4 + blocklen - 1) / blocklen;

    olen *= blocklen;

    if (olen < 2 * blocklen) {

        /* Key too small */

        return 0;

    }

    if (inlen > 0xFF) {

        /* Key too large */

        return 0;

    }

    if (out) {

        /* Set header */

        out[0] = (unsigned char)inlen;

        out[1] = in[0] ^ 0xFF;

        out[2] = in[1] ^ 0xFF;

        out[3] = in[2] ^ 0xFF;

        memcpy(out + 4, in, inlen);

        /* Add random padding to end */

        if (olen > inlen + 4

            && RAND_bytes(out + 4 + inlen, olen - 4 - inlen) <= 0)

            return 0;

        /* Encrypt twice */

        if (!EVP_EncryptUpdate(ctx, out, &dummy, out, olen)

            || !EVP_EncryptUpdate(ctx, out, &dummy, out, olen))

            return 0;

    }

    *outlen = olen;

    return 1;

}

/* Encrypt/Decrypt content key in PWRI recipient info */

int cms_RecipientInfo_pwri_crypt(CMS_ContentInfo *cms, CMS_RecipientInfo *ri,

                                 int en_de)

{

    CMS_EncryptedContentInfo *ec;

    CMS_PasswordRecipientInfo *pwri;

    int r = 0;

    X509_ALGOR *algtmp, *kekalg = NULL;

    EVP_CIPHER_CTX *kekctx = NULL;

    const EVP_CIPHER *kekcipher;

    unsigned char *key = NULL;

    size_t keylen;

    ec = cms->d.envelopedData->encryptedContentInfo;

    pwri = ri->d.pwri;

    if (!pwri->pass) {

        CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT, CMS_R_NO_PASSWORD);

        return 0;

    }

    algtmp = pwri->keyEncryptionAlgorithm;

    if (!algtmp || OBJ_obj2nid(algtmp->algorithm) != NID_id_alg_PWRI_KEK) {

        CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT,

               CMS_R_UNSUPPORTED_KEY_ENCRYPTION_ALGORITHM);

        return 0;

    }

    kekalg = ASN1_TYPE_unpack_sequence(ASN1_ITEM_rptr(X509_ALGOR),

                                       algtmp->parameter);

    if (kekalg == NULL) {

        CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT,

               CMS_R_INVALID_KEY_ENCRYPTION_PARAMETER);

        return 0;

    }

    kekcipher = EVP_get_cipherbyobj(kekalg->algorithm);

    if (!kekcipher) {

        CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT, CMS_R_UNKNOWN_CIPHER);

        return 0;

    }

    kekctx = EVP_CIPHER_CTX_new();

    if (kekctx == NULL) {

        CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT, ERR_R_MALLOC_FAILURE);

        return 0;

    }

    /* Fixup cipher based on AlgorithmIdentifier to set IV etc */

    if (!EVP_CipherInit_ex(kekctx, kekcipher, NULL, NULL, NULL, en_de))

        goto err;

    EVP_CIPHER_CTX_set_padding(kekctx, 0);

    if (EVP_CIPHER_asn1_to_param(kekctx, kekalg->parameter) <= 0) {

        CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT,

               CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);

        goto err;

    }

    algtmp = pwri->keyDerivationAlgorithm;

    /* Finish password based key derivation to setup key in "ctx" */

    if (EVP_PBE_CipherInit(algtmp->algorithm,

                           (char *)pwri->pass, pwri->passlen,

                           algtmp->parameter, kekctx, en_de) < 0) {

        CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT, ERR_R_EVP_LIB);

        goto err;

    }

    /* Finally wrap/unwrap the key */

    if (en_de) {

        if (!kek_wrap_key(NULL, &keylen, ec->key, ec->keylen, kekctx))

            goto err;

        key = OPENSSL_malloc(keylen);

        if (key == NULL)

            goto err;

        if (!kek_wrap_key(key, &keylen, ec->key, ec->keylen, kekctx))

            goto err;

        pwri->encryptedKey->data = key;

        pwri->encryptedKey->length = keylen;

    } else {

        key = OPENSSL_malloc(pwri->encryptedKey->length);

        if (key == NULL) {

            CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT, ERR_R_MALLOC_FAILURE);

            goto err;

        }

        if (!kek_unwrap_key(key, &keylen,

                            pwri->encryptedKey->data,

                            pwri->encryptedKey->length, kekctx)) {

            CMSerr(CMS_F_CMS_RECIPIENTINFO_PWRI_CRYPT, CMS_R_UNWRAP_FAILURE);

            goto err;

        }

        OPENSSL_clear_free(ec->key, ec->keylen);

        ec->key = key;

        ec->keylen = keylen;

    }

    r = 1;

 err:

    EVP_CIPHER_CTX_free(kekctx);

    if (!r)

        OPENSSL_free(key);

    X509_ALGOR_free(kekalg);

    return r;

}