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1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2  * All rights reserved.
3  *
4  * This package is an SSL implementation written
5  * by Eric Young (eay@cryptsoft.com).
6  * The implementation was written so as to conform with Netscapes SSL.
7  *
8  * This library is free for commercial and non-commercial use as long as
9  * the following conditions are aheared to.  The following conditions
10  * apply to all code found in this distribution, be it the RC4, RSA,
11  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
12  * included with this distribution is covered by the same copyright terms
13  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14  *
15  * Copyright remains Eric Young's, and as such any Copyright notices in
16  * the code are not to be removed.
17  * If this package is used in a product, Eric Young should be given attribution
18  * as the author of the parts of the library used.
19  * This can be in the form of a textual message at program startup or
20  * in documentation (online or textual) provided with the package.
21  *
22  * Redistribution and use in source and binary forms, with or without
23  * modification, are permitted provided that the following conditions
24  * are met:
25  * 1. Redistributions of source code must retain the copyright
26  *    notice, this list of conditions and the following disclaimer.
27  * 2. Redistributions in binary form must reproduce the above copyright
28  *    notice, this list of conditions and the following disclaimer in the
29  *    documentation and/or other materials provided with the distribution.
30  * 3. All advertising materials mentioning features or use of this software
31  *    must display the following acknowledgement:
32  *    "This product includes cryptographic software written by
33  *     Eric Young (eay@cryptsoft.com)"
34  *    The word 'cryptographic' can be left out if the rouines from the library
35  *    being used are not cryptographic related :-).
36  * 4. If you include any Windows specific code (or a derivative thereof) from
37  *    the apps directory (application code) you must include an acknowledgement:
38  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39  *
40  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50  * SUCH DAMAGE.
51  *
52  * The licence and distribution terms for any publically available version or
53  * derivative of this code cannot be changed.  i.e. this code cannot simply be
54  * copied and put under another distribution licence
55  * [including the GNU Public Licence.] */
56 
57 #include <openssl/evp.h>
58 
59 #include <string.h>
60 
61 #include <openssl/bytestring.h>
62 #include <openssl/dsa.h>
63 #include <openssl/ec_key.h>
64 #include <openssl/err.h>
65 #include <openssl/rsa.h>
66 
67 #include "internal.h"
68 #include "../internal.h"
69 
70 
71 static const EVP_PKEY_ASN1_METHOD *const kASN1Methods[] = {
72     &rsa_asn1_meth,
73     &ec_asn1_meth,
74     &dsa_asn1_meth,
75     &ed25519_asn1_meth,
76 };
77 
parse_key_type(CBS * cbs,int * out_type)78 static int parse_key_type(CBS *cbs, int *out_type) {
79   CBS oid;
80   if (!CBS_get_asn1(cbs, &oid, CBS_ASN1_OBJECT)) {
81     return 0;
82   }
83 
84   for (unsigned i = 0; i < OPENSSL_ARRAY_SIZE(kASN1Methods); i++) {
85     const EVP_PKEY_ASN1_METHOD *method = kASN1Methods[i];
86     if (CBS_len(&oid) == method->oid_len &&
87         OPENSSL_memcmp(CBS_data(&oid), method->oid, method->oid_len) == 0) {
88       *out_type = method->pkey_id;
89       return 1;
90     }
91   }
92 
93   return 0;
94 }
95 
EVP_parse_public_key(CBS * cbs)96 EVP_PKEY *EVP_parse_public_key(CBS *cbs) {
97   // Parse the SubjectPublicKeyInfo.
98   CBS spki, algorithm, key;
99   int type;
100   uint8_t padding;
101   if (!CBS_get_asn1(cbs, &spki, CBS_ASN1_SEQUENCE) ||
102       !CBS_get_asn1(&spki, &algorithm, CBS_ASN1_SEQUENCE) ||
103       !CBS_get_asn1(&spki, &key, CBS_ASN1_BITSTRING) ||
104       CBS_len(&spki) != 0) {
105     OPENSSL_PUT_ERROR(EVP, EVP_R_DECODE_ERROR);
106     return NULL;
107   }
108   if (!parse_key_type(&algorithm, &type)) {
109     OPENSSL_PUT_ERROR(EVP, EVP_R_UNSUPPORTED_ALGORITHM);
110     return NULL;
111   }
112   if (// Every key type defined encodes the key as a byte string with the same
113       // conversion to BIT STRING.
114       !CBS_get_u8(&key, &padding) ||
115       padding != 0) {
116     OPENSSL_PUT_ERROR(EVP, EVP_R_DECODE_ERROR);
117     return NULL;
118   }
119 
120   // Set up an |EVP_PKEY| of the appropriate type.
121   EVP_PKEY *ret = EVP_PKEY_new();
122   if (ret == NULL ||
123       !EVP_PKEY_set_type(ret, type)) {
124     goto err;
125   }
126 
127   // Call into the type-specific SPKI decoding function.
128   if (ret->ameth->pub_decode == NULL) {
129     OPENSSL_PUT_ERROR(EVP, EVP_R_UNSUPPORTED_ALGORITHM);
130     goto err;
131   }
132   if (!ret->ameth->pub_decode(ret, &algorithm, &key)) {
133     goto err;
134   }
135 
136   return ret;
137 
138 err:
139   EVP_PKEY_free(ret);
140   return NULL;
141 }
142 
EVP_marshal_public_key(CBB * cbb,const EVP_PKEY * key)143 int EVP_marshal_public_key(CBB *cbb, const EVP_PKEY *key) {
144   if (key->ameth == NULL || key->ameth->pub_encode == NULL) {
145     OPENSSL_PUT_ERROR(EVP, EVP_R_UNSUPPORTED_ALGORITHM);
146     return 0;
147   }
148 
149   return key->ameth->pub_encode(cbb, key);
150 }
151 
EVP_parse_private_key(CBS * cbs)152 EVP_PKEY *EVP_parse_private_key(CBS *cbs) {
153   // Parse the PrivateKeyInfo.
154   CBS pkcs8, algorithm, key;
155   uint64_t version;
156   int type;
157   if (!CBS_get_asn1(cbs, &pkcs8, CBS_ASN1_SEQUENCE) ||
158       !CBS_get_asn1_uint64(&pkcs8, &version) ||
159       version != 0 ||
160       !CBS_get_asn1(&pkcs8, &algorithm, CBS_ASN1_SEQUENCE) ||
161       !CBS_get_asn1(&pkcs8, &key, CBS_ASN1_OCTETSTRING)) {
162     OPENSSL_PUT_ERROR(EVP, EVP_R_DECODE_ERROR);
163     return NULL;
164   }
165   if (!parse_key_type(&algorithm, &type)) {
166     OPENSSL_PUT_ERROR(EVP, EVP_R_UNSUPPORTED_ALGORITHM);
167     return NULL;
168   }
169 
170   // A PrivateKeyInfo ends with a SET of Attributes which we ignore.
171 
172   // Set up an |EVP_PKEY| of the appropriate type.
173   EVP_PKEY *ret = EVP_PKEY_new();
174   if (ret == NULL ||
175       !EVP_PKEY_set_type(ret, type)) {
176     goto err;
177   }
178 
179   // Call into the type-specific PrivateKeyInfo decoding function.
180   if (ret->ameth->priv_decode == NULL) {
181     OPENSSL_PUT_ERROR(EVP, EVP_R_UNSUPPORTED_ALGORITHM);
182     goto err;
183   }
184   if (!ret->ameth->priv_decode(ret, &algorithm, &key)) {
185     goto err;
186   }
187 
188   return ret;
189 
190 err:
191   EVP_PKEY_free(ret);
192   return NULL;
193 }
194 
EVP_marshal_private_key(CBB * cbb,const EVP_PKEY * key)195 int EVP_marshal_private_key(CBB *cbb, const EVP_PKEY *key) {
196   if (key->ameth == NULL || key->ameth->priv_encode == NULL) {
197     OPENSSL_PUT_ERROR(EVP, EVP_R_UNSUPPORTED_ALGORITHM);
198     return 0;
199   }
200 
201   return key->ameth->priv_encode(cbb, key);
202 }
203 
old_priv_decode(CBS * cbs,int type)204 static EVP_PKEY *old_priv_decode(CBS *cbs, int type) {
205   EVP_PKEY *ret = EVP_PKEY_new();
206   if (ret == NULL) {
207     return NULL;
208   }
209 
210   switch (type) {
211     case EVP_PKEY_EC: {
212       EC_KEY *ec_key = EC_KEY_parse_private_key(cbs, NULL);
213       if (ec_key == NULL || !EVP_PKEY_assign_EC_KEY(ret, ec_key)) {
214         EC_KEY_free(ec_key);
215         goto err;
216       }
217       return ret;
218     }
219     case EVP_PKEY_DSA: {
220       DSA *dsa = DSA_parse_private_key(cbs);
221       if (dsa == NULL || !EVP_PKEY_assign_DSA(ret, dsa)) {
222         DSA_free(dsa);
223         goto err;
224       }
225       return ret;
226     }
227     case EVP_PKEY_RSA: {
228       RSA *rsa = RSA_parse_private_key(cbs);
229       if (rsa == NULL || !EVP_PKEY_assign_RSA(ret, rsa)) {
230         RSA_free(rsa);
231         goto err;
232       }
233       return ret;
234     }
235     default:
236       OPENSSL_PUT_ERROR(EVP, EVP_R_UNKNOWN_PUBLIC_KEY_TYPE);
237       goto err;
238   }
239 
240 err:
241   EVP_PKEY_free(ret);
242   return NULL;
243 }
244 
d2i_PrivateKey(int type,EVP_PKEY ** out,const uint8_t ** inp,long len)245 EVP_PKEY *d2i_PrivateKey(int type, EVP_PKEY **out, const uint8_t **inp,
246                          long len) {
247   if (len < 0) {
248     OPENSSL_PUT_ERROR(EVP, EVP_R_DECODE_ERROR);
249     return NULL;
250   }
251 
252   // Parse with the legacy format.
253   CBS cbs;
254   CBS_init(&cbs, *inp, (size_t)len);
255   EVP_PKEY *ret = old_priv_decode(&cbs, type);
256   if (ret == NULL) {
257     // Try again with PKCS#8.
258     ERR_clear_error();
259     CBS_init(&cbs, *inp, (size_t)len);
260     ret = EVP_parse_private_key(&cbs);
261     if (ret == NULL) {
262       return NULL;
263     }
264     if (ret->type != type) {
265       OPENSSL_PUT_ERROR(EVP, EVP_R_DIFFERENT_KEY_TYPES);
266       EVP_PKEY_free(ret);
267       return NULL;
268     }
269   }
270 
271   if (out != NULL) {
272     EVP_PKEY_free(*out);
273     *out = ret;
274   }
275   *inp = CBS_data(&cbs);
276   return ret;
277 }
278 
279 // num_elements parses one SEQUENCE from |in| and returns the number of elements
280 // in it. On parse error, it returns zero.
num_elements(const uint8_t * in,size_t in_len)281 static size_t num_elements(const uint8_t *in, size_t in_len) {
282   CBS cbs, sequence;
283   CBS_init(&cbs, in, (size_t)in_len);
284 
285   if (!CBS_get_asn1(&cbs, &sequence, CBS_ASN1_SEQUENCE)) {
286     return 0;
287   }
288 
289   size_t count = 0;
290   while (CBS_len(&sequence) > 0) {
291     if (!CBS_get_any_asn1_element(&sequence, NULL, NULL, NULL)) {
292       return 0;
293     }
294 
295     count++;
296   }
297 
298   return count;
299 }
300 
d2i_AutoPrivateKey(EVP_PKEY ** out,const uint8_t ** inp,long len)301 EVP_PKEY *d2i_AutoPrivateKey(EVP_PKEY **out, const uint8_t **inp, long len) {
302   if (len < 0) {
303     OPENSSL_PUT_ERROR(EVP, EVP_R_DECODE_ERROR);
304     return NULL;
305   }
306 
307   // Parse the input as a PKCS#8 PrivateKeyInfo.
308   CBS cbs;
309   CBS_init(&cbs, *inp, (size_t)len);
310   EVP_PKEY *ret = EVP_parse_private_key(&cbs);
311   if (ret != NULL) {
312     if (out != NULL) {
313       EVP_PKEY_free(*out);
314       *out = ret;
315     }
316     *inp = CBS_data(&cbs);
317     return ret;
318   }
319   ERR_clear_error();
320 
321   // Count the elements to determine the legacy key format.
322   switch (num_elements(*inp, (size_t)len)) {
323     case 4:
324       return d2i_PrivateKey(EVP_PKEY_EC, out, inp, len);
325 
326     case 6:
327       return d2i_PrivateKey(EVP_PKEY_DSA, out, inp, len);
328 
329     default:
330       return d2i_PrivateKey(EVP_PKEY_RSA, out, inp, len);
331   }
332 }
333 
i2d_PublicKey(const EVP_PKEY * key,uint8_t ** outp)334 int i2d_PublicKey(const EVP_PKEY *key, uint8_t **outp) {
335   switch (key->type) {
336     case EVP_PKEY_RSA:
337       return i2d_RSAPublicKey(key->pkey.rsa, outp);
338     case EVP_PKEY_DSA:
339       return i2d_DSAPublicKey(key->pkey.dsa, outp);
340     case EVP_PKEY_EC:
341       return i2o_ECPublicKey(key->pkey.ec, outp);
342     default:
343       OPENSSL_PUT_ERROR(EVP, EVP_R_UNSUPPORTED_PUBLIC_KEY_TYPE);
344       return -1;
345   }
346 }
347 
d2i_PublicKey(int type,EVP_PKEY ** out,const uint8_t ** inp,long len)348 EVP_PKEY *d2i_PublicKey(int type, EVP_PKEY **out, const uint8_t **inp,
349                         long len) {
350   EVP_PKEY *ret = EVP_PKEY_new();
351   if (ret == NULL) {
352     return NULL;
353   }
354 
355   CBS cbs;
356   CBS_init(&cbs, *inp, len < 0 ? 0 : (size_t)len);
357   switch (type) {
358     case EVP_PKEY_RSA: {
359       RSA *rsa = RSA_parse_public_key(&cbs);
360       if (rsa == NULL || !EVP_PKEY_assign_RSA(ret, rsa)) {
361         RSA_free(rsa);
362         goto err;
363       }
364       break;
365     }
366 
367     // Unlike OpenSSL, we do not support EC keys with this API. The raw EC
368     // public key serialization requires knowing the group. In OpenSSL, calling
369     // this function with |EVP_PKEY_EC| and setting |out| to NULL does not work.
370     // It requires |*out| to include a partially-initiazed |EVP_PKEY| to extract
371     // the group.
372     default:
373       OPENSSL_PUT_ERROR(EVP, EVP_R_UNSUPPORTED_PUBLIC_KEY_TYPE);
374       goto err;
375   }
376 
377   *inp = CBS_data(&cbs);
378   if (out != NULL) {
379     EVP_PKEY_free(*out);
380     *out = ret;
381   }
382   return ret;
383 
384 err:
385   EVP_PKEY_free(ret);
386   return NULL;
387 }
388