1/*
2 * Copyright 2006-2023 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 <assert.h>
11#include <openssl/cms.h>
12#include <openssl/err.h>
13#include <openssl/core_names.h>
14#include "crypto/asn1.h"
15#include "crypto/rsa.h"
16#include "crypto/evp.h"
17#include "cms_local.h"
18
19static RSA_OAEP_PARAMS *rsa_oaep_decode(const X509_ALGOR *alg)
20{
21    RSA_OAEP_PARAMS *oaep;
22
23    oaep = ASN1_TYPE_unpack_sequence(ASN1_ITEM_rptr(RSA_OAEP_PARAMS),
24                                     alg->parameter);
25
26    if (oaep == NULL)
27        return NULL;
28
29    if (oaep->maskGenFunc != NULL) {
30        oaep->maskHash = ossl_x509_algor_mgf1_decode(oaep->maskGenFunc);
31        if (oaep->maskHash == NULL) {
32            RSA_OAEP_PARAMS_free(oaep);
33            return NULL;
34        }
35    }
36    return oaep;
37}
38
39static int rsa_cms_decrypt(CMS_RecipientInfo *ri)
40{
41    EVP_PKEY_CTX *pkctx;
42    X509_ALGOR *cmsalg;
43    int nid;
44    int rv = -1;
45    unsigned char *label = NULL;
46    int labellen = 0;
47    const EVP_MD *mgf1md = NULL, *md = NULL;
48    RSA_OAEP_PARAMS *oaep;
49
50    pkctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
51    if (pkctx == NULL)
52        return 0;
53    if (!CMS_RecipientInfo_ktri_get0_algs(ri, NULL, NULL, &cmsalg))
54        return -1;
55    nid = OBJ_obj2nid(cmsalg->algorithm);
56    if (nid == NID_rsaEncryption)
57        return 1;
58    if (nid != NID_rsaesOaep) {
59        ERR_raise(ERR_LIB_CMS, CMS_R_UNSUPPORTED_ENCRYPTION_TYPE);
60        return -1;
61    }
62    /* Decode OAEP parameters */
63    oaep = rsa_oaep_decode(cmsalg);
64
65    if (oaep == NULL) {
66        ERR_raise(ERR_LIB_CMS, CMS_R_INVALID_OAEP_PARAMETERS);
67        goto err;
68    }
69
70    mgf1md = ossl_x509_algor_get_md(oaep->maskHash);
71    if (mgf1md == NULL)
72        goto err;
73    md = ossl_x509_algor_get_md(oaep->hashFunc);
74    if (md == NULL)
75        goto err;
76
77    if (oaep->pSourceFunc != NULL) {
78        X509_ALGOR *plab = oaep->pSourceFunc;
79
80        if (OBJ_obj2nid(plab->algorithm) != NID_pSpecified) {
81            ERR_raise(ERR_LIB_CMS, CMS_R_UNSUPPORTED_LABEL_SOURCE);
82            goto err;
83        }
84        if (plab->parameter->type != V_ASN1_OCTET_STRING) {
85            ERR_raise(ERR_LIB_CMS, CMS_R_INVALID_LABEL);
86            goto err;
87        }
88
89        label = plab->parameter->value.octet_string->data;
90        /* Stop label being freed when OAEP parameters are freed */
91        plab->parameter->value.octet_string->data = NULL;
92        labellen = plab->parameter->value.octet_string->length;
93    }
94
95    if (EVP_PKEY_CTX_set_rsa_padding(pkctx, RSA_PKCS1_OAEP_PADDING) <= 0)
96        goto err;
97    if (EVP_PKEY_CTX_set_rsa_oaep_md(pkctx, md) <= 0)
98        goto err;
99    if (EVP_PKEY_CTX_set_rsa_mgf1_md(pkctx, mgf1md) <= 0)
100        goto err;
101    if (label != NULL
102            && EVP_PKEY_CTX_set0_rsa_oaep_label(pkctx, label, labellen) <= 0) {
103        OPENSSL_free(label);
104        goto err;
105    }
106    /* Carry on */
107    rv = 1;
108
109 err:
110    RSA_OAEP_PARAMS_free(oaep);
111    return rv;
112}
113
114static int rsa_cms_encrypt(CMS_RecipientInfo *ri)
115{
116    const EVP_MD *md, *mgf1md;
117    RSA_OAEP_PARAMS *oaep = NULL;
118    ASN1_STRING *os = NULL;
119    ASN1_OCTET_STRING *los = NULL;
120    X509_ALGOR *alg;
121    EVP_PKEY_CTX *pkctx = CMS_RecipientInfo_get0_pkey_ctx(ri);
122    int pad_mode = RSA_PKCS1_PADDING, rv = 0, labellen;
123    unsigned char *label;
124
125    if (CMS_RecipientInfo_ktri_get0_algs(ri, NULL, NULL, &alg) <= 0)
126        return 0;
127    if (pkctx != NULL) {
128        if (EVP_PKEY_CTX_get_rsa_padding(pkctx, &pad_mode) <= 0)
129            return 0;
130    }
131    if (pad_mode == RSA_PKCS1_PADDING)
132        return X509_ALGOR_set0(alg, OBJ_nid2obj(NID_rsaEncryption),
133                               V_ASN1_NULL, NULL);
134
135    /* Not supported */
136    if (pad_mode != RSA_PKCS1_OAEP_PADDING)
137        return 0;
138    if (EVP_PKEY_CTX_get_rsa_oaep_md(pkctx, &md) <= 0)
139        goto err;
140    if (EVP_PKEY_CTX_get_rsa_mgf1_md(pkctx, &mgf1md) <= 0)
141        goto err;
142    labellen = EVP_PKEY_CTX_get0_rsa_oaep_label(pkctx, &label);
143    if (labellen < 0)
144        goto err;
145    oaep = RSA_OAEP_PARAMS_new();
146    if (oaep == NULL)
147        goto err;
148    if (!ossl_x509_algor_new_from_md(&oaep->hashFunc, md))
149        goto err;
150    if (!ossl_x509_algor_md_to_mgf1(&oaep->maskGenFunc, mgf1md))
151        goto err;
152    if (labellen > 0) {
153        oaep->pSourceFunc = X509_ALGOR_new();
154        if (oaep->pSourceFunc == NULL)
155            goto err;
156        los = ASN1_OCTET_STRING_new();
157        if (los == NULL)
158            goto err;
159        if (!ASN1_OCTET_STRING_set(los, label, labellen))
160            goto err;
161
162        if (!X509_ALGOR_set0(oaep->pSourceFunc, OBJ_nid2obj(NID_pSpecified),
163                        V_ASN1_OCTET_STRING, los))
164            goto err;
165
166        los = NULL;
167    }
168    /* create string with oaep parameter encoding. */
169    if (!ASN1_item_pack(oaep, ASN1_ITEM_rptr(RSA_OAEP_PARAMS), &os))
170        goto err;
171    if (!X509_ALGOR_set0(alg, OBJ_nid2obj(NID_rsaesOaep), V_ASN1_SEQUENCE, os))
172        goto err;
173    os = NULL;
174    rv = 1;
175 err:
176    RSA_OAEP_PARAMS_free(oaep);
177    ASN1_STRING_free(os);
178    ASN1_OCTET_STRING_free(los);
179    return rv;
180}
181
182int ossl_cms_rsa_envelope(CMS_RecipientInfo *ri, int decrypt)
183{
184    assert(decrypt == 0 || decrypt == 1);
185
186    if (decrypt == 1)
187        return rsa_cms_decrypt(ri);
188
189    if (decrypt == 0)
190        return rsa_cms_encrypt(ri);
191
192    ERR_raise(ERR_LIB_CMS, CMS_R_NOT_SUPPORTED_FOR_THIS_KEY_TYPE);
193    return 0;
194}
195
196static int rsa_cms_sign(CMS_SignerInfo *si)
197{
198    int pad_mode = RSA_PKCS1_PADDING;
199    X509_ALGOR *alg;
200    EVP_PKEY_CTX *pkctx = CMS_SignerInfo_get0_pkey_ctx(si);
201    unsigned char aid[128];
202    const unsigned char *pp = aid;
203    size_t aid_len = 0;
204    OSSL_PARAM params[2];
205
206    CMS_SignerInfo_get0_algs(si, NULL, NULL, NULL, &alg);
207    if (pkctx != NULL) {
208        if (EVP_PKEY_CTX_get_rsa_padding(pkctx, &pad_mode) <= 0)
209            return 0;
210    }
211    if (pad_mode == RSA_PKCS1_PADDING) {
212        X509_ALGOR_set0(alg, OBJ_nid2obj(NID_rsaEncryption), V_ASN1_NULL, 0);
213        return 1;
214    }
215    /* We don't support it */
216    if (pad_mode != RSA_PKCS1_PSS_PADDING)
217        return 0;
218
219    if (evp_pkey_ctx_is_legacy(pkctx)) {
220        /* No provider -> we cannot query it for algorithm ID. */
221        ASN1_STRING *os = NULL;
222
223        os = ossl_rsa_ctx_to_pss_string(pkctx);
224        if (os == NULL)
225            return 0;
226        return X509_ALGOR_set0(alg, OBJ_nid2obj(EVP_PKEY_RSA_PSS), V_ASN1_SEQUENCE, os);
227    }
228
229    params[0] = OSSL_PARAM_construct_octet_string(
230        OSSL_SIGNATURE_PARAM_ALGORITHM_ID, aid, sizeof(aid));
231    params[1] = OSSL_PARAM_construct_end();
232
233    if (EVP_PKEY_CTX_get_params(pkctx, params) <= 0)
234        return 0;
235    if ((aid_len = params[0].return_size) == 0)
236        return 0;
237    if (d2i_X509_ALGOR(&alg, &pp, aid_len) == NULL)
238        return 0;
239    return 1;
240}
241
242static int rsa_cms_verify(CMS_SignerInfo *si)
243{
244    int nid, nid2;
245    X509_ALGOR *alg;
246    EVP_PKEY_CTX *pkctx = CMS_SignerInfo_get0_pkey_ctx(si);
247    EVP_PKEY *pkey = EVP_PKEY_CTX_get0_pkey(pkctx);
248
249    CMS_SignerInfo_get0_algs(si, NULL, NULL, NULL, &alg);
250    nid = OBJ_obj2nid(alg->algorithm);
251    if (nid == EVP_PKEY_RSA_PSS)
252        return ossl_rsa_pss_to_ctx(NULL, pkctx, alg, NULL) > 0;
253    /* Only PSS allowed for PSS keys */
254    if (EVP_PKEY_is_a(pkey, "RSA-PSS")) {
255        ERR_raise(ERR_LIB_RSA, RSA_R_ILLEGAL_OR_UNSUPPORTED_PADDING_MODE);
256        return 0;
257    }
258    if (nid == NID_rsaEncryption)
259        return 1;
260    /* Workaround for some implementation that use a signature OID */
261    if (OBJ_find_sigid_algs(nid, NULL, &nid2)) {
262        if (nid2 == NID_rsaEncryption)
263            return 1;
264    }
265    return 0;
266}
267
268int ossl_cms_rsa_sign(CMS_SignerInfo *si, int verify)
269{
270    assert(verify == 0 || verify == 1);
271
272    if (verify == 1)
273        return rsa_cms_verify(si);
274
275    if (verify == 0)
276        return rsa_cms_sign(si);
277
278    ERR_raise(ERR_LIB_CMS, CMS_R_NOT_SUPPORTED_FOR_THIS_KEY_TYPE);
279    return 0;
280}
281