1/*
2 * Copyright 2008-2023 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License").  You may not use
5 * this file except in compliance with the License.  You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10#include "internal/cryptlib.h"
11#include <openssl/asn1t.h>
12#include <openssl/pem.h>
13#include <openssl/x509v3.h>
14#include <openssl/err.h>
15#include <openssl/cms.h>
16#include <openssl/rand.h>
17#include "crypto/evp.h"
18#include "crypto/asn1.h"
19#include "cms_local.h"
20
21/* CMS EncryptedData Utilities */
22
23/* Return BIO based on EncryptedContentInfo and key */
24
25BIO *ossl_cms_EncryptedContent_init_bio(CMS_EncryptedContentInfo *ec,
26                                        const CMS_CTX *cms_ctx)
27{
28    BIO *b;
29    EVP_CIPHER_CTX *ctx;
30    EVP_CIPHER *fetched_ciph = NULL;
31    const EVP_CIPHER *cipher = NULL;
32    X509_ALGOR *calg = ec->contentEncryptionAlgorithm;
33    evp_cipher_aead_asn1_params aparams;
34    unsigned char iv[EVP_MAX_IV_LENGTH], *piv = NULL;
35    unsigned char *tkey = NULL;
36    int len;
37    int ivlen = 0;
38    size_t tkeylen = 0;
39    int ok = 0;
40    int enc, keep_key = 0;
41    OSSL_LIB_CTX *libctx = ossl_cms_ctx_get0_libctx(cms_ctx);
42    const char *propq = ossl_cms_ctx_get0_propq(cms_ctx);
43
44    enc = ec->cipher ? 1 : 0;
45
46    b = BIO_new(BIO_f_cipher());
47    if (b == NULL) {
48        ERR_raise(ERR_LIB_CMS, ERR_R_MALLOC_FAILURE);
49        return NULL;
50    }
51
52    BIO_get_cipher_ctx(b, &ctx);
53
54    (void)ERR_set_mark();
55    if (enc) {
56        cipher = ec->cipher;
57        /*
58         * If not keeping key set cipher to NULL so subsequent calls decrypt.
59         */
60        if (ec->key != NULL)
61            ec->cipher = NULL;
62    } else {
63        cipher = EVP_get_cipherbyobj(calg->algorithm);
64    }
65    if (cipher != NULL) {
66        fetched_ciph = EVP_CIPHER_fetch(libctx, EVP_CIPHER_get0_name(cipher),
67                                        propq);
68        if (fetched_ciph != NULL)
69            cipher = fetched_ciph;
70    }
71    if (cipher == NULL) {
72        (void)ERR_clear_last_mark();
73        ERR_raise(ERR_LIB_CMS, CMS_R_UNKNOWN_CIPHER);
74        goto err;
75    }
76    (void)ERR_pop_to_mark();
77
78    if (EVP_CipherInit_ex(ctx, cipher, NULL, NULL, NULL, enc) <= 0) {
79        ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_INITIALISATION_ERROR);
80        goto err;
81    }
82
83    if (enc) {
84        calg->algorithm = OBJ_nid2obj(EVP_CIPHER_CTX_get_type(ctx));
85        if (calg->algorithm == NULL || calg->algorithm->nid == NID_undef) {
86            ERR_raise(ERR_LIB_CMS, CMS_R_UNSUPPORTED_CONTENT_ENCRYPTION_ALGORITHM);
87            goto err;
88        }
89        /* Generate a random IV if we need one */
90        ivlen = EVP_CIPHER_CTX_get_iv_length(ctx);
91        if (ivlen < 0) {
92            ERR_raise(ERR_LIB_CMS, ERR_R_EVP_LIB);
93            goto err;
94        }
95
96        if (ivlen > 0) {
97            if (RAND_bytes_ex(libctx, iv, ivlen, 0) <= 0)
98                goto err;
99            piv = iv;
100        }
101    } else {
102        if (evp_cipher_asn1_to_param_ex(ctx, calg->parameter, &aparams) <= 0) {
103            ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
104            goto err;
105        }
106        if ((EVP_CIPHER_get_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER)) {
107            piv = aparams.iv;
108            if (ec->taglen > 0
109                    && EVP_CIPHER_CTX_ctrl(ctx, EVP_CTRL_AEAD_SET_TAG,
110                                           ec->taglen, ec->tag) <= 0) {
111                ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_AEAD_SET_TAG_ERROR);
112                goto err;
113            }
114        }
115    }
116    len = EVP_CIPHER_CTX_get_key_length(ctx);
117    if (len <= 0)
118        goto err;
119    tkeylen = (size_t)len;
120
121    /* Generate random session key */
122    if (!enc || !ec->key) {
123        tkey = OPENSSL_malloc(tkeylen);
124        if (tkey == NULL) {
125            ERR_raise(ERR_LIB_CMS, ERR_R_MALLOC_FAILURE);
126            goto err;
127        }
128        if (EVP_CIPHER_CTX_rand_key(ctx, tkey) <= 0)
129            goto err;
130    }
131
132    if (!ec->key) {
133        ec->key = tkey;
134        ec->keylen = tkeylen;
135        tkey = NULL;
136        if (enc)
137            keep_key = 1;
138        else
139            ERR_clear_error();
140
141    }
142
143    if (ec->keylen != tkeylen) {
144        /* If necessary set key length */
145        if (EVP_CIPHER_CTX_set_key_length(ctx, ec->keylen) <= 0) {
146            /*
147             * Only reveal failure if debugging so we don't leak information
148             * which may be useful in MMA.
149             */
150            if (enc || ec->debug) {
151                ERR_raise(ERR_LIB_CMS, CMS_R_INVALID_KEY_LENGTH);
152                goto err;
153            } else {
154                /* Use random key */
155                OPENSSL_clear_free(ec->key, ec->keylen);
156                ec->key = tkey;
157                ec->keylen = tkeylen;
158                tkey = NULL;
159                ERR_clear_error();
160            }
161        }
162    }
163
164    if (EVP_CipherInit_ex(ctx, NULL, NULL, ec->key, piv, enc) <= 0) {
165        ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_INITIALISATION_ERROR);
166        goto err;
167    }
168    if (enc) {
169        calg->parameter = ASN1_TYPE_new();
170        if (calg->parameter == NULL) {
171            ERR_raise(ERR_LIB_CMS, ERR_R_MALLOC_FAILURE);
172            goto err;
173        }
174        if ((EVP_CIPHER_get_flags(cipher) & EVP_CIPH_FLAG_AEAD_CIPHER)) {
175            memcpy(aparams.iv, piv, ivlen);
176            aparams.iv_len = ivlen;
177            aparams.tag_len = EVP_CIPHER_CTX_get_tag_length(ctx);
178            if (aparams.tag_len <= 0)
179                goto err;
180        }
181
182        if (evp_cipher_param_to_asn1_ex(ctx, calg->parameter, &aparams) <= 0) {
183            ERR_raise(ERR_LIB_CMS, CMS_R_CIPHER_PARAMETER_INITIALISATION_ERROR);
184            goto err;
185        }
186        /* If parameter type not set omit parameter */
187        if (calg->parameter->type == V_ASN1_UNDEF) {
188            ASN1_TYPE_free(calg->parameter);
189            calg->parameter = NULL;
190        }
191    }
192    ok = 1;
193
194 err:
195    EVP_CIPHER_free(fetched_ciph);
196    if (!keep_key || !ok) {
197        OPENSSL_clear_free(ec->key, ec->keylen);
198        ec->key = NULL;
199    }
200    OPENSSL_clear_free(tkey, tkeylen);
201    if (ok)
202        return b;
203    BIO_free(b);
204    return NULL;
205}
206
207int ossl_cms_EncryptedContent_init(CMS_EncryptedContentInfo *ec,
208                                   const EVP_CIPHER *cipher,
209                                   const unsigned char *key, size_t keylen,
210                                   const CMS_CTX *cms_ctx)
211{
212    ec->cipher = cipher;
213    if (key) {
214        if ((ec->key = OPENSSL_malloc(keylen)) == NULL) {
215            ERR_raise(ERR_LIB_CMS, ERR_R_MALLOC_FAILURE);
216            return 0;
217        }
218        memcpy(ec->key, key, keylen);
219    }
220    ec->keylen = keylen;
221    if (cipher != NULL)
222        ec->contentType = OBJ_nid2obj(NID_pkcs7_data);
223    return 1;
224}
225
226int CMS_EncryptedData_set1_key(CMS_ContentInfo *cms, const EVP_CIPHER *ciph,
227                               const unsigned char *key, size_t keylen)
228{
229    CMS_EncryptedContentInfo *ec;
230
231    if (!key || !keylen) {
232        ERR_raise(ERR_LIB_CMS, CMS_R_NO_KEY);
233        return 0;
234    }
235    if (ciph) {
236        cms->d.encryptedData = M_ASN1_new_of(CMS_EncryptedData);
237        if (!cms->d.encryptedData) {
238            ERR_raise(ERR_LIB_CMS, ERR_R_MALLOC_FAILURE);
239            return 0;
240        }
241        cms->contentType = OBJ_nid2obj(NID_pkcs7_encrypted);
242        cms->d.encryptedData->version = 0;
243    } else if (OBJ_obj2nid(cms->contentType) != NID_pkcs7_encrypted) {
244        ERR_raise(ERR_LIB_CMS, CMS_R_NOT_ENCRYPTED_DATA);
245        return 0;
246    }
247    ec = cms->d.encryptedData->encryptedContentInfo;
248    return ossl_cms_EncryptedContent_init(ec, ciph, key, keylen,
249                                          ossl_cms_get0_cmsctx(cms));
250}
251
252BIO *ossl_cms_EncryptedData_init_bio(const CMS_ContentInfo *cms)
253{
254    CMS_EncryptedData *enc = cms->d.encryptedData;
255    if (enc->encryptedContentInfo->cipher && enc->unprotectedAttrs)
256        enc->version = 2;
257    return ossl_cms_EncryptedContent_init_bio(enc->encryptedContentInfo,
258                                              ossl_cms_get0_cmsctx(cms));
259}
260