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251 lines
7.7 KiB
C

/*
* Copyright 2008-2020 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 "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 "crypto/evp.h"
#include "cms_local.h"
/* CMS EncryptedData Utilities */
/* Return BIO based on EncryptedContentInfo and key */
BIO *cms_EncryptedContent_init_bio(CMS_EncryptedContentInfo *ec,
const CMS_CTX *cms_ctx)
{
BIO *b;
EVP_CIPHER_CTX *ctx;
EVP_CIPHER *fetched_ciph = NULL;
const EVP_CIPHER *cipher = NULL;
X509_ALGOR *calg = ec->contentEncryptionAlgorithm;
evp_cipher_aead_asn1_params aparams;
unsigned char iv[EVP_MAX_IV_LENGTH], *piv = NULL;
unsigned char *tkey = NULL;
int len;
int ivlen = 0;
size_t tkeylen = 0;
int ok = 0;
int enc, keep_key = 0;
enc = ec->cipher ? 1 : 0;
b = BIO_new(BIO_f_cipher());
if (b == NULL) {
CMSerr(CMS_F_CMS_ENCRYPTEDCONTENT_INIT_BIO, ERR_R_MALLOC_FAILURE);
return NULL;
}
BIO_get_cipher_ctx(b, &ctx);
(void)ERR_set_mark();
if (enc) {
cipher = ec->cipher;
/*
* If not keeping key set cipher to NULL so subsequent calls decrypt.
*/
if (ec->key != NULL)
ec->cipher = NULL;
} else {
cipher = EVP_get_cipherbyobj(calg->algorithm);
}
if (cipher != NULL) {
fetched_ciph = EVP_CIPHER_fetch(cms_ctx->libctx, EVP_CIPHER_name(cipher),
cms_ctx->propq);
if (fetched_ciph != NULL)
cipher = fetched_ciph;
}
if (cipher == NULL) {
(void)ERR_clear_last_mark();
CMSerr(CMS_F_CMS_ENCRYPTEDCONTENT_INIT_BIO, CMS_R_UNKNOWN_CIPHER);
goto err;
}
(void)ERR_pop_to_mark();
if (EVP_CipherInit_ex(ctx, cipher, NULL, NULL, NULL, enc) <= 0) {
CMSerr(CMS_F_CMS_ENCRYPTEDCONTENT_INIT_BIO,
CMS_R_CIPHER_INITIALISATION_ERROR);
goto err;
}
if (enc) {
calg->algorithm = OBJ_nid2obj(EVP_CIPHER_CTX_type(ctx));
/* Generate a random IV if we need one */
ivlen = EVP_CIPHER_CTX_iv_length(ctx);
if (ivlen > 0) {
if (RAND_bytes_ex(cms_ctx->libctx, iv, ivlen) <= 0)
goto err;
piv = iv;
}
} else {
if (evp_cipher_asn1_to_param_ex(ctx, calg->parameter, &aparams) <= 0) {
CMSerr(0, CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
goto err;
}
if ((EVP_CIPHER_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER)) {
piv = aparams.iv;
if (ec->taglen > 0
&& EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG,
ec->taglen, ec->tag) <= 0) {
CMSerr(0, CMS_R_CIPHER_AEAD_SET_TAG_ERROR);
goto err;
}
}
}
len = EVP_CIPHER_CTX_key_length(ctx);
if (len <= 0)
goto err;
tkeylen = (size_t)len;
/* Generate random session key */
if (!enc || !ec->key) {
tkey = OPENSSL_malloc(tkeylen);
if (tkey == NULL) {
CMSerr(CMS_F_CMS_ENCRYPTEDCONTENT_INIT_BIO, ERR_R_MALLOC_FAILURE);
goto err;
}
if (EVP_CIPHER_CTX_rand_key(ctx, tkey) <= 0)
goto err;
}
if (!ec->key) {
ec->key = tkey;
ec->keylen = tkeylen;
tkey = NULL;
if (enc)
keep_key = 1;
else
ERR_clear_error();
}
if (ec->keylen != tkeylen) {
/* If necessary set key length */
if (EVP_CIPHER_CTX_set_key_length(ctx, ec->keylen) <= 0) {
/*
* Only reveal failure if debugging so we don't leak information
* which may be useful in MMA.
*/
if (enc || ec->debug) {
CMSerr(CMS_F_CMS_ENCRYPTEDCONTENT_INIT_BIO,
CMS_R_INVALID_KEY_LENGTH);
goto err;
} else {
/* Use random key */
OPENSSL_clear_free(ec->key, ec->keylen);
ec->key = tkey;
ec->keylen = tkeylen;
tkey = NULL;
ERR_clear_error();
}
}
}
if (EVP_CipherInit_ex(ctx, NULL, NULL, ec->key, piv, enc) <= 0) {
CMSerr(CMS_F_CMS_ENCRYPTEDCONTENT_INIT_BIO,
CMS_R_CIPHER_INITIALISATION_ERROR);
goto err;
}
if (enc) {
calg->parameter = ASN1_TYPE_new();
if (calg->parameter == NULL) {
CMSerr(CMS_F_CMS_ENCRYPTEDCONTENT_INIT_BIO, ERR_R_MALLOC_FAILURE);
goto err;
}
if ((EVP_CIPHER_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER)) {
memcpy(aparams.iv, piv, ivlen);
aparams.iv_len = ivlen;
aparams.tag_len = EVP_CIPHER_CTX_tag_length(ctx);
if (aparams.tag_len <= 0)
goto err;
}
if (evp_cipher_param_to_asn1_ex(ctx, calg->parameter, &aparams) <= 0) {
CMSerr(CMS_F_CMS_ENCRYPTEDCONTENT_INIT_BIO,
CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
goto err;
}
/* If parameter type not set omit parameter */
if (calg->parameter->type == V_ASN1_UNDEF) {
ASN1_TYPE_free(calg->parameter);
calg->parameter = NULL;
}
}
ok = 1;
err:
EVP_CIPHER_free(fetched_ciph);
if (!keep_key || !ok) {
OPENSSL_clear_free(ec->key, ec->keylen);
ec->key = NULL;
}
OPENSSL_clear_free(tkey, tkeylen);
if (ok)
return b;
BIO_free(b);
return NULL;
}
int cms_EncryptedContent_init(CMS_EncryptedContentInfo *ec,
const EVP_CIPHER *cipher,
const unsigned char *key, size_t keylen,
const CMS_CTX *cms_ctx)
{
ec->cipher = cipher;
if (key) {
if ((ec->key = OPENSSL_malloc(keylen)) == NULL) {
CMSerr(CMS_F_CMS_ENCRYPTEDCONTENT_INIT, ERR_R_MALLOC_FAILURE);
return 0;
}
memcpy(ec->key, key, keylen);
}
ec->keylen = keylen;
if (cipher != NULL)
ec->contentType = OBJ_nid2obj(NID_pkcs7_data);
return 1;
}
int CMS_EncryptedData_set1_key(CMS_ContentInfo *cms, const EVP_CIPHER *ciph,
const unsigned char *key, size_t keylen)
{
CMS_EncryptedContentInfo *ec;
if (!key || !keylen) {
CMSerr(CMS_F_CMS_ENCRYPTEDDATA_SET1_KEY, CMS_R_NO_KEY);
return 0;
}
if (ciph) {
cms->d.encryptedData = M_ASN1_new_of(CMS_EncryptedData);
if (!cms->d.encryptedData) {
CMSerr(CMS_F_CMS_ENCRYPTEDDATA_SET1_KEY, ERR_R_MALLOC_FAILURE);
return 0;
}
cms->contentType = OBJ_nid2obj(NID_pkcs7_encrypted);
cms->d.encryptedData->version = 0;
} else if (OBJ_obj2nid(cms->contentType) != NID_pkcs7_encrypted) {
CMSerr(CMS_F_CMS_ENCRYPTEDDATA_SET1_KEY, CMS_R_NOT_ENCRYPTED_DATA);
return 0;
}
ec = cms->d.encryptedData->encryptedContentInfo;
return cms_EncryptedContent_init(ec, ciph, key, keylen, cms_get0_cmsctx(cms));
}
BIO *cms_EncryptedData_init_bio(const CMS_ContentInfo *cms)
{
CMS_EncryptedData *enc = cms->d.encryptedData;
if (enc->encryptedContentInfo->cipher && enc->unprotectedAttrs)
enc->version = 2;
return cms_EncryptedContent_init_bio(enc->encryptedContentInfo,
cms_get0_cmsctx(cms));
}