cms_pwri.c

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/* crypto/cms/cms_pwri.c */
/* Written by Dr Stephen N Henson ([email protected]) for the OpenSSL
 * project.
 */
/* ====================================================================
 * Copyright (c) 2009 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    [email protected].
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 */

#include "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_lcl.h"
#include "asn1_locl.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;
    X509_ALGOR *encalg = NULL;
    unsigned char iv[EVP_MAX_IV_LENGTH];
    int ivlen;
    env = cms_get0_enveloped(cms);
    if (!env)
        goto err;

    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();
    EVP_CIPHER_CTX_init(&ctx);

    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_pseudo_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_cleanup(&ctx);

    /* Initialize recipient info */
    ri = M_ASN1_new_of(CMS_RecipientInfo);
    if (!ri)
        goto merr;

    ri->d.pwri = M_ASN1_new_of(CMS_PasswordRecipientInfo);
    if (!ri->d.pwri)
        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)
        goto merr;
    pwri->keyEncryptionAlgorithm->algorithm = OBJ_nid2obj(wrap_nid);
    pwri->keyEncryptionAlgorithm->parameter = ASN1_TYPE_new();
    if (!pwri->keyEncryptionAlgorithm->parameter)
        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_cleanup(&ctx);
    if (ri)
        M_ASN1_free_of(ri, CMS_RecipientInfo);
    if (encalg)
        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;
        }
    tmp = OPENSSL_malloc(inlen);
    /* setup IV by decrypting last two blocks */
    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);
    /* 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_cleanse(tmp, inlen);
    OPENSSL_free(tmp);
    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_pseudo_bytes(out + 4 + inlen, olen - 4 - inlen);
        /* Encrypt twice */
        EVP_EncryptUpdate(ctx, out, &dummy, out, olen);
        EVP_EncryptUpdate(ctx, out, &dummy, out, olen);
        }

    *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;
    const unsigned char *p = NULL;
    int plen;
    int r = 0;
    X509_ALGOR *algtmp, *kekalg = NULL;
    EVP_CIPHER_CTX kekctx;
    const EVP_CIPHER *kekcipher;
    unsigned char *key = NULL;
    size_t keylen;

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

    pwri = ri->d.pwri;
    EVP_CIPHER_CTX_init(&kekctx);

    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;
        }

    if (algtmp->parameter->type == V_ASN1_SEQUENCE)
        {
        p = algtmp->parameter->value.sequence->data;
        plen = algtmp->parameter->value.sequence->length;
        kekalg = d2i_X509_ALGOR(NULL, &p, plen);
        }
    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);
        goto err;
        }

    /* 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)
            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)
            {
            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;
            }

        ec->key = key;
        ec->keylen = keylen;

        }

    r = 1;

    err:

    EVP_CIPHER_CTX_cleanup(&kekctx);

    if (!r && key)
        OPENSSL_free(key);
    X509_ALGOR_free(kekalg);

    return r;

    }