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openssl/crypto/cms/cms_kari.c

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/*
* Copyright 2013-2019 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/aes.h>
#include "cms_local.h"
#include "crypto/asn1.h"
/* Key Agreement Recipient Info (KARI) routines */
int CMS_RecipientInfo_kari_get0_alg(CMS_RecipientInfo *ri,
X509_ALGOR **palg,
ASN1_OCTET_STRING **pukm)
{
if (ri->type != CMS_RECIPINFO_AGREE) {
CMSerr(CMS_F_CMS_RECIPIENTINFO_KARI_GET0_ALG,
CMS_R_NOT_KEY_AGREEMENT);
return 0;
}
if (palg)
*palg = ri->d.kari->keyEncryptionAlgorithm;
if (pukm)
*pukm = ri->d.kari->ukm;
return 1;
}
/* Retrieve recipient encrypted keys from a kari */
STACK_OF(CMS_RecipientEncryptedKey)
*CMS_RecipientInfo_kari_get0_reks(CMS_RecipientInfo *ri)
{
if (ri->type != CMS_RECIPINFO_AGREE) {
CMSerr(CMS_F_CMS_RECIPIENTINFO_KARI_GET0_REKS,
CMS_R_NOT_KEY_AGREEMENT);
return NULL;
}
return ri->d.kari->recipientEncryptedKeys;
}
int CMS_RecipientInfo_kari_get0_orig_id(CMS_RecipientInfo *ri,
X509_ALGOR **pubalg,
ASN1_BIT_STRING **pubkey,
ASN1_OCTET_STRING **keyid,
X509_NAME **issuer,
ASN1_INTEGER **sno)
{
CMS_OriginatorIdentifierOrKey *oik;
if (ri->type != CMS_RECIPINFO_AGREE) {
CMSerr(CMS_F_CMS_RECIPIENTINFO_KARI_GET0_ORIG_ID,
CMS_R_NOT_KEY_AGREEMENT);
return 0;
}
oik = ri->d.kari->originator;
if (issuer)
*issuer = NULL;
if (sno)
*sno = NULL;
if (keyid)
*keyid = NULL;
if (pubalg)
*pubalg = NULL;
if (pubkey)
*pubkey = NULL;
if (oik->type == CMS_OIK_ISSUER_SERIAL) {
if (issuer)
*issuer = oik->d.issuerAndSerialNumber->issuer;
if (sno)
*sno = oik->d.issuerAndSerialNumber->serialNumber;
} else if (oik->type == CMS_OIK_KEYIDENTIFIER) {
if (keyid)
*keyid = oik->d.subjectKeyIdentifier;
} else if (oik->type == CMS_OIK_PUBKEY) {
if (pubalg)
*pubalg = oik->d.originatorKey->algorithm;
if (pubkey)
*pubkey = oik->d.originatorKey->publicKey;
} else
return 0;
return 1;
}
int CMS_RecipientInfo_kari_orig_id_cmp(CMS_RecipientInfo *ri, X509 *cert)
{
CMS_OriginatorIdentifierOrKey *oik;
if (ri->type != CMS_RECIPINFO_AGREE) {
CMSerr(CMS_F_CMS_RECIPIENTINFO_KARI_ORIG_ID_CMP,
CMS_R_NOT_KEY_AGREEMENT);
return -2;
}
oik = ri->d.kari->originator;
if (oik->type == CMS_OIK_ISSUER_SERIAL)
return cms_ias_cert_cmp(oik->d.issuerAndSerialNumber, cert);
else if (oik->type == CMS_OIK_KEYIDENTIFIER)
return cms_keyid_cert_cmp(oik->d.subjectKeyIdentifier, cert);
return -1;
}
int CMS_RecipientEncryptedKey_get0_id(CMS_RecipientEncryptedKey *rek,
ASN1_OCTET_STRING **keyid,
ASN1_GENERALIZEDTIME **tm,
CMS_OtherKeyAttribute **other,
X509_NAME **issuer, ASN1_INTEGER **sno)
{
CMS_KeyAgreeRecipientIdentifier *rid = rek->rid;
if (rid->type == CMS_REK_ISSUER_SERIAL) {
if (issuer)
*issuer = rid->d.issuerAndSerialNumber->issuer;
if (sno)
*sno = rid->d.issuerAndSerialNumber->serialNumber;
if (keyid)
*keyid = NULL;
if (tm)
*tm = NULL;
if (other)
*other = NULL;
} else if (rid->type == CMS_REK_KEYIDENTIFIER) {
if (keyid)
*keyid = rid->d.rKeyId->subjectKeyIdentifier;
if (tm)
*tm = rid->d.rKeyId->date;
if (other)
*other = rid->d.rKeyId->other;
if (issuer)
*issuer = NULL;
if (sno)
*sno = NULL;
} else
return 0;
return 1;
}
int CMS_RecipientEncryptedKey_cert_cmp(CMS_RecipientEncryptedKey *rek,
X509 *cert)
{
CMS_KeyAgreeRecipientIdentifier *rid = rek->rid;
if (rid->type == CMS_REK_ISSUER_SERIAL)
return cms_ias_cert_cmp(rid->d.issuerAndSerialNumber, cert);
else if (rid->type == CMS_REK_KEYIDENTIFIER)
return cms_keyid_cert_cmp(rid->d.rKeyId->subjectKeyIdentifier, cert);
else
return -1;
}
int CMS_RecipientInfo_kari_set0_pkey(CMS_RecipientInfo *ri, EVP_PKEY *pk)
{
EVP_PKEY_CTX *pctx;
CMS_KeyAgreeRecipientInfo *kari = ri->d.kari;
EVP_PKEY_CTX_free(kari->pctx);
kari->pctx = NULL;
if (!pk)
return 1;
pctx = EVP_PKEY_CTX_new(pk, NULL);
if (!pctx || EVP_PKEY_derive_init(pctx) <= 0)
goto err;
kari->pctx = pctx;
return 1;
err:
EVP_PKEY_CTX_free(pctx);
return 0;
}
EVP_CIPHER_CTX *CMS_RecipientInfo_kari_get0_ctx(CMS_RecipientInfo *ri)
{
if (ri->type == CMS_RECIPINFO_AGREE)
return ri->d.kari->ctx;
return NULL;
}
/*
* Derive KEK and decrypt/encrypt with it to produce either the original CEK
* or the encrypted CEK.
*/
static int cms_kek_cipher(unsigned char **pout, size_t *poutlen,
const unsigned char *in, size_t inlen,
CMS_KeyAgreeRecipientInfo *kari, int enc)
{
/* Key encryption key */
unsigned char kek[EVP_MAX_KEY_LENGTH];
size_t keklen;
int rv = 0;
unsigned char *out = NULL;
int outlen;
keklen = EVP_CIPHER_CTX_key_length(kari->ctx);
if (keklen > EVP_MAX_KEY_LENGTH)
return 0;
/* Derive KEK */
if (EVP_PKEY_derive(kari->pctx, kek, &keklen) <= 0)
goto err;
/* Set KEK in context */
if (!EVP_CipherInit_ex(kari->ctx, NULL, NULL, kek, NULL, enc))
goto err;
/* obtain output length of ciphered key */
if (!EVP_CipherUpdate(kari->ctx, NULL, &outlen, in, inlen))
goto err;
out = OPENSSL_malloc(outlen);
if (out == NULL)
goto err;
if (!EVP_CipherUpdate(kari->ctx, out, &outlen, in, inlen))
goto err;
*pout = out;
*poutlen = (size_t)outlen;
rv = 1;
err:
OPENSSL_cleanse(kek, keklen);
if (!rv)
OPENSSL_free(out);
EVP_CIPHER_CTX_reset(kari->ctx);
/* FIXME: WHY IS kari->pctx freed here? /RL */
EVP_PKEY_CTX_free(kari->pctx);
kari->pctx = NULL;
return rv;
}
int CMS_RecipientInfo_kari_decrypt(CMS_ContentInfo *cms,
CMS_RecipientInfo *ri,
CMS_RecipientEncryptedKey *rek)
{
int rv = 0;
unsigned char *enckey = NULL, *cek = NULL;
size_t enckeylen;
size_t ceklen;
CMS_EncryptedContentInfo *ec;
enckeylen = rek->encryptedKey->length;
enckey = rek->encryptedKey->data;
/* Setup all parameters to derive KEK */
if (!cms_env_asn1_ctrl(ri, 1))
goto err;
/* Attempt to decrypt CEK */
if (!cms_kek_cipher(&cek, &ceklen, enckey, enckeylen, ri->d.kari, 0))
goto err;
ec = cms->d.envelopedData->encryptedContentInfo;
OPENSSL_clear_free(ec->key, ec->keylen);
ec->key = cek;
ec->keylen = ceklen;
cek = NULL;
rv = 1;
err:
OPENSSL_free(cek);
return rv;
}
/* Create ephemeral key and initialise context based on it */
static int cms_kari_create_ephemeral_key(CMS_KeyAgreeRecipientInfo *kari,
EVP_PKEY *pk)
{
EVP_PKEY_CTX *pctx = NULL;
EVP_PKEY *ekey = NULL;
int rv = 0;
pctx = EVP_PKEY_CTX_new(pk, NULL);
if (!pctx)
goto err;
if (EVP_PKEY_keygen_init(pctx) <= 0)
goto err;
if (EVP_PKEY_keygen(pctx, &ekey) <= 0)
goto err;
EVP_PKEY_CTX_free(pctx);
pctx = EVP_PKEY_CTX_new(ekey, NULL);
if (!pctx)
goto err;
if (EVP_PKEY_derive_init(pctx) <= 0)
goto err;
kari->pctx = pctx;
rv = 1;
err:
if (!rv)
EVP_PKEY_CTX_free(pctx);
EVP_PKEY_free(ekey);
return rv;
}
/* Initialise a kari based on passed certificate and key */
int cms_RecipientInfo_kari_init(CMS_RecipientInfo *ri, X509 *recip,
EVP_PKEY *pk, unsigned int flags)
{
CMS_KeyAgreeRecipientInfo *kari;
CMS_RecipientEncryptedKey *rek = NULL;
ri->d.kari = M_ASN1_new_of(CMS_KeyAgreeRecipientInfo);
if (!ri->d.kari)
return 0;
ri->type = CMS_RECIPINFO_AGREE;
kari = ri->d.kari;
kari->version = 3;
rek = M_ASN1_new_of(CMS_RecipientEncryptedKey);
if (rek == NULL)
return 0;
if (!sk_CMS_RecipientEncryptedKey_push(kari->recipientEncryptedKeys, rek)) {
M_ASN1_free_of(rek, CMS_RecipientEncryptedKey);
return 0;
}
if (flags & CMS_USE_KEYID) {
rek->rid->type = CMS_REK_KEYIDENTIFIER;
rek->rid->d.rKeyId = M_ASN1_new_of(CMS_RecipientKeyIdentifier);
if (rek->rid->d.rKeyId == NULL)
return 0;
if (!cms_set1_keyid(&rek->rid->d.rKeyId->subjectKeyIdentifier, recip))
return 0;
} else {
rek->rid->type = CMS_REK_ISSUER_SERIAL;
if (!cms_set1_ias(&rek->rid->d.issuerAndSerialNumber, recip))
return 0;
}
/* Create ephemeral key */
if (!cms_kari_create_ephemeral_key(kari, pk))
return 0;
EVP_PKEY_up_ref(pk);
rek->pkey = pk;
return 1;
}
static int cms_wrap_init(CMS_KeyAgreeRecipientInfo *kari,
const EVP_CIPHER *cipher)
{
EVP_CIPHER_CTX *ctx = kari->ctx;
const EVP_CIPHER *kekcipher;
int keylen = EVP_CIPHER_key_length(cipher);
/* If a suitable wrap algorithm is already set nothing to do */
kekcipher = EVP_CIPHER_CTX_cipher(ctx);
if (kekcipher) {
if (EVP_CIPHER_CTX_mode(ctx) != EVP_CIPH_WRAP_MODE)
return 0;
return 1;
}
/*
* Pick a cipher based on content encryption cipher. If it is DES3 use
* DES3 wrap otherwise use AES wrap similar to key size.
*/
#ifndef OPENSSL_NO_DES
if (EVP_CIPHER_type(cipher) == NID_des_ede3_cbc)
kekcipher = EVP_des_ede3_wrap();
else
#endif
if (keylen <= 16)
kekcipher = EVP_aes_128_wrap();
else if (keylen <= 24)
kekcipher = EVP_aes_192_wrap();
else
kekcipher = EVP_aes_256_wrap();
return EVP_EncryptInit_ex(ctx, kekcipher, NULL, NULL, NULL);
}
/* Encrypt content key in key agreement recipient info */
int cms_RecipientInfo_kari_encrypt(CMS_ContentInfo *cms,
CMS_RecipientInfo *ri)
{
CMS_KeyAgreeRecipientInfo *kari;
CMS_EncryptedContentInfo *ec;
CMS_RecipientEncryptedKey *rek;
STACK_OF(CMS_RecipientEncryptedKey) *reks;
int i;
if (ri->type != CMS_RECIPINFO_AGREE) {
CMSerr(CMS_F_CMS_RECIPIENTINFO_KARI_ENCRYPT, CMS_R_NOT_KEY_AGREEMENT);
return 0;
}
kari = ri->d.kari;
reks = kari->recipientEncryptedKeys;
ec = cms->d.envelopedData->encryptedContentInfo;
/* Initialise wrap algorithm parameters */
if (!cms_wrap_init(kari, ec->cipher))
return 0;
/*
* If no originator key set up initialise for ephemeral key the public key
* ASN1 structure will set the actual public key value.
*/
if (kari->originator->type == -1) {
CMS_OriginatorIdentifierOrKey *oik = kari->originator;
oik->type = CMS_OIK_PUBKEY;
oik->d.originatorKey = M_ASN1_new_of(CMS_OriginatorPublicKey);
if (!oik->d.originatorKey)
return 0;
}
/* Initialise KDF algorithm */
if (!cms_env_asn1_ctrl(ri, 0))
return 0;
/* For each rek, derive KEK, encrypt CEK */
for (i = 0; i < sk_CMS_RecipientEncryptedKey_num(reks); i++) {
unsigned char *enckey;
size_t enckeylen;
rek = sk_CMS_RecipientEncryptedKey_value(reks, i);
if (EVP_PKEY_derive_set_peer(kari->pctx, rek->pkey) <= 0)
return 0;
if (!cms_kek_cipher(&enckey, &enckeylen, ec->key, ec->keylen,
kari, 1))
return 0;
ASN1_STRING_set0(rek->encryptedKey, enckey, enckeylen);
}
return 1;
}
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