24f37cbed4c28130691bd4fa03ff4085d3dad7f0
[openssl.git] / crypto / kdf / sshkdf.c
1 /*
2  * Copyright 2018-2018 The OpenSSL Project Authors. All Rights Reserved.
3  *
4  * Licensed under the OpenSSL license (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 <stdlib.h>
11 #include <stdarg.h>
12 #include <string.h>
13 #include <openssl/evp.h>
14 #include <openssl/kdf.h>
15 #include "internal/cryptlib.h"
16 #include "internal/evp_int.h"
17 #include "kdf_local.h"
18
19 /* See RFC 4253, Section 7.2 */
20
21 static void kdf_sshkdf_reset(EVP_KDF_IMPL *impl);
22 static int SSHKDF(const EVP_MD *evp_md,
23                   const unsigned char *key, size_t key_len,
24                   const unsigned char *xcghash, size_t xcghash_len,
25                   const unsigned char *session_id, size_t session_id_len,
26                   char type, unsigned char *okey, size_t okey_len);
27
28 struct evp_kdf_impl_st {
29     const EVP_MD *md;
30     unsigned char *key; /* K */
31     size_t key_len;
32     unsigned char *xcghash; /* H */
33     size_t xcghash_len;
34     char type; /* X */
35     unsigned char *session_id;
36     size_t session_id_len;
37 };
38
39 static EVP_KDF_IMPL *kdf_sshkdf_new(void)
40 {
41     EVP_KDF_IMPL *impl;
42
43     if ((impl = OPENSSL_zalloc(sizeof(*impl))) == NULL)
44         KDFerr(KDF_F_KDF_SSHKDF_NEW, ERR_R_MALLOC_FAILURE);
45     return impl;
46 }
47
48 static void kdf_sshkdf_free(EVP_KDF_IMPL *impl)
49 {
50     kdf_sshkdf_reset(impl);
51     OPENSSL_free(impl);
52 }
53
54 static void kdf_sshkdf_reset(EVP_KDF_IMPL *impl)
55 {
56     OPENSSL_clear_free(impl->key, impl->key_len);
57     OPENSSL_clear_free(impl->xcghash, impl->xcghash_len);
58     OPENSSL_clear_free(impl->session_id, impl->session_id_len);
59     memset(impl, 0, sizeof(*impl));
60 }
61
62 static int kdf_sshkdf_parse_buffer_arg(unsigned char **dst, size_t *dst_len,
63                                        va_list args)
64 {
65     const unsigned char *p;
66     size_t len;
67
68     p = va_arg(args, const unsigned char *);
69     len = va_arg(args, size_t);
70     OPENSSL_clear_free(*dst, *dst_len);
71     *dst = OPENSSL_memdup(p, len);
72     if (*dst == NULL)
73         return 0;
74
75     *dst_len = len;
76     return 1;
77 }
78
79 static int kdf_sshkdf_ctrl(EVP_KDF_IMPL *impl, int cmd, va_list args)
80 {
81     int t;
82
83     switch (cmd) {
84     case EVP_KDF_CTRL_SET_MD:
85         impl->md = va_arg(args, const EVP_MD *);
86         if (impl->md == NULL)
87             return 0;
88
89         return 1;
90
91     case EVP_KDF_CTRL_SET_KEY:
92         return kdf_sshkdf_parse_buffer_arg(&impl->key,
93                                            &impl->key_len, args);
94
95     case EVP_KDF_CTRL_SET_SSHKDF_XCGHASH:
96         return kdf_sshkdf_parse_buffer_arg(&impl->xcghash,
97                                            &impl->xcghash_len, args);
98
99     case EVP_KDF_CTRL_SET_SSHKDF_SESSION_ID:
100         return kdf_sshkdf_parse_buffer_arg(&impl->session_id,
101                                            &impl->session_id_len, args);
102
103     case EVP_KDF_CTRL_SET_SSHKDF_TYPE:
104         t = va_arg(args, int);
105         if (t < 65 || t > 70) {
106             KDFerr(KDF_F_KDF_SSHKDF_CTRL, KDF_R_VALUE_ERROR);
107             return 0;
108         }
109
110         impl->type = (char)t;
111         return 1;
112
113     default:
114         return -2;
115
116     }
117 }
118
119 static int kdf_sshkdf_ctrl_str(EVP_KDF_IMPL *impl, const char *type,
120                                const char *value)
121 {
122     if (value == NULL) {
123         KDFerr(KDF_F_KDF_SSHKDF_CTRL_STR, KDF_R_VALUE_MISSING);
124         return 0;
125     }
126
127     if (strcmp(type, "md") == 0)
128         return kdf_md2ctrl(impl, kdf_sshkdf_ctrl, EVP_KDF_CTRL_SET_MD, value);
129
130     if (strcmp(type, "key") == 0)
131         return kdf_str2ctrl(impl, kdf_sshkdf_ctrl,
132                             EVP_KDF_CTRL_SET_KEY, value);
133
134     if (strcmp(type, "hexkey") == 0)
135         return kdf_hex2ctrl(impl, kdf_sshkdf_ctrl,
136                             EVP_KDF_CTRL_SET_KEY, value);
137
138     if (strcmp(type, "xcghash") == 0)
139         return kdf_str2ctrl(impl, kdf_sshkdf_ctrl,
140                             EVP_KDF_CTRL_SET_SSHKDF_XCGHASH, value);
141
142     if (strcmp(type, "hexxcghash") == 0)
143         return kdf_hex2ctrl(impl, kdf_sshkdf_ctrl,
144                             EVP_KDF_CTRL_SET_SSHKDF_XCGHASH, value);
145
146     if (strcmp(type, "session_id") == 0)
147         return kdf_str2ctrl(impl, kdf_sshkdf_ctrl,
148                             EVP_KDF_CTRL_SET_SSHKDF_SESSION_ID, value);
149
150     if (strcmp(type, "hexsession_id") == 0)
151         return kdf_hex2ctrl(impl, kdf_sshkdf_ctrl,
152                             EVP_KDF_CTRL_SET_SSHKDF_SESSION_ID, value);
153
154     if (strcmp(type, "type") == 0) {
155         if (strlen(value) != 1) {
156             KDFerr(KDF_F_KDF_SSHKDF_CTRL_STR, KDF_R_VALUE_ERROR);
157             return 0;
158         }
159
160         return call_ctrl(kdf_sshkdf_ctrl, impl, EVP_KDF_CTRL_SET_SSHKDF_TYPE,
161                          (int)value[0]);
162     }
163
164     KDFerr(KDF_F_KDF_SSHKDF_CTRL_STR, KDF_R_UNKNOWN_PARAMETER_TYPE);
165     return -2;
166 }
167
168 static size_t kdf_sshkdf_size(EVP_KDF_IMPL *impl)
169 {
170     return SIZE_MAX;
171 }
172
173 static int kdf_sshkdf_derive(EVP_KDF_IMPL *impl, unsigned char *key,
174                              size_t keylen)
175 {
176     if (impl->md == NULL) {
177         KDFerr(KDF_F_KDF_SSHKDF_DERIVE, KDF_R_MISSING_MESSAGE_DIGEST);
178         return 0;
179     }
180     if (impl->key == NULL) {
181         KDFerr(KDF_F_KDF_SSHKDF_DERIVE, KDF_R_MISSING_KEY);
182         return 0;
183     }
184     if (impl->xcghash == NULL) {
185         KDFerr(KDF_F_KDF_SSHKDF_DERIVE, KDF_R_MISSING_XCGHASH);
186         return 0;
187     }
188     if (impl->session_id == NULL) {
189         KDFerr(KDF_F_KDF_SSHKDF_DERIVE, KDF_R_MISSING_SESSION_ID);
190         return 0;
191     }
192     if (impl->type == 0) {
193         KDFerr(KDF_F_KDF_SSHKDF_DERIVE, KDF_R_MISSING_TYPE);
194         return 0;
195     }
196     return SSHKDF(impl->md, impl->key, impl->key_len,
197                   impl->xcghash, impl->xcghash_len,
198                   impl->session_id, impl->session_id_len,
199                   impl->type, key, keylen);
200 }
201
202 const EVP_KDF_METHOD sshkdf_kdf_meth = {
203     EVP_KDF_SSHKDF,
204     kdf_sshkdf_new,
205     kdf_sshkdf_free,
206     kdf_sshkdf_reset,
207     kdf_sshkdf_ctrl,
208     kdf_sshkdf_ctrl_str,
209     kdf_sshkdf_size,
210     kdf_sshkdf_derive,
211 };
212
213 static int SSHKDF(const EVP_MD *evp_md,
214                   const unsigned char *key, size_t key_len,
215                   const unsigned char *xcghash, size_t xcghash_len,
216                   const unsigned char *session_id, size_t session_id_len,
217                   char type, unsigned char *okey, size_t okey_len)
218 {
219     EVP_MD_CTX *md = NULL;
220     unsigned char digest[EVP_MAX_MD_SIZE];
221     unsigned int dsize = 0;
222     size_t cursize = 0;
223     int ret = 0;
224
225     md = EVP_MD_CTX_new();
226     if (md == NULL)
227         return 0;
228
229     if (!EVP_DigestInit_ex(md, evp_md, NULL))
230         goto out;
231
232     if (!EVP_DigestUpdate(md, key, key_len))
233         goto out;
234
235     if (!EVP_DigestUpdate(md, xcghash, xcghash_len))
236         goto out;
237
238     if (!EVP_DigestUpdate(md, &type, 1))
239         goto out;
240
241     if (!EVP_DigestUpdate(md, session_id, session_id_len))
242         goto out;
243
244     if (!EVP_DigestFinal_ex(md, digest, &dsize))
245         goto out;
246
247     if (okey_len < dsize) {
248         memcpy(okey, digest, okey_len);
249         ret = 1;
250         goto out;
251     }
252
253     memcpy(okey, digest, dsize);
254
255     for (cursize = dsize; cursize < okey_len; cursize += dsize) {
256
257         if (!EVP_DigestInit_ex(md, evp_md, NULL))
258             goto out;
259
260         if (!EVP_DigestUpdate(md, key, key_len))
261             goto out;
262
263         if (!EVP_DigestUpdate(md, xcghash, xcghash_len))
264             goto out;
265
266         if (!EVP_DigestUpdate(md, okey, cursize))
267             goto out;
268
269         if (!EVP_DigestFinal_ex(md, digest, &dsize))
270             goto out;
271
272         if (okey_len < cursize + dsize) {
273             memcpy(okey + cursize, digest, okey_len - cursize);
274             ret = 1;
275             goto out;
276         }
277
278         memcpy(okey + cursize, digest, dsize);
279     }
280
281     ret = 1;
282
283 out:
284     EVP_MD_CTX_free(md);
285     OPENSSL_cleanse(digest, EVP_MAX_MD_SIZE);
286     return ret;
287 }
288