gvpe/src/hkdf.C

/*
    hkdf.C -- RFC 5869 HKDF implementation
    Copyright (C) 2013      Marc Lehmann <gvpe@schmorp.de>
 
    This file is part of GVPE.

    GVPE is free software; you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by the
    Free Software Foundation; either version 3 of the License, or (at your
    option) any later version.
   
    This program is distributed in the hope that it will be useful, but
    WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
    Public License for more details.
   
    You should have received a copy of the GNU General Public License along
    with this program; if not, see <http://www.gnu.org/licenses/>.
   
    Additional permission under GNU GPL version 3 section 7
   
    If you modify this Program, or any covered work, by linking or
    combining it with the OpenSSL project's OpenSSL library (or a modified
    version of that library), containing parts covered by the terms of the
    OpenSSL or SSLeay licenses, the licensors of this Program grant you
    additional permission to convey the resulting work.  Corresponding
    Source for a non-source form of such a combination shall include the
    source code for the parts of OpenSSL used as well as that of the
    covered work.
*/

#include "config.h"

#include <cstring>

#include <openssl/rand.h>
#include <openssl/hmac.h>

#include "util.h"
#include "hkdf.h"

hkdf::hkdf (const void *salt, int len, const EVP_MD *hash)
{
  HMAC_CTX_init (&ctx);

  if (!salt)
    {
      memset (prk, 0, sizeof prk);
      salt = prk;
      len  = EVP_MD_size (hash);
    }

  require (HMAC_Init_ex (&ctx, salt, len, hash, 0));
}

hkdf::~hkdf ()
{
  HMAC_CTX_cleanup (&ctx);
}

void
hkdf::extract (const void *ikm, int len)
{
  require (HMAC_Update (&ctx, (u8 *)ikm, len));
}

void
hkdf::extract_done ()
{
  require (HMAC_Final (&ctx, prk, 0));
}

void
hkdf::expand (void *okm, int len, const void *info, int infolen)
{
  u8 tn[sizeof prk];
  u8 iter = 0;
  int md_size = HMAC_size (&ctx);

  while (len)
    {
      require (HMAC_Init_ex (&ctx, prk, md_size, 0, 0));

      if (iter)
        require (HMAC_Update (&ctx, tn, md_size));

      require (HMAC_Update (&ctx, (u8 *)info, infolen));


      ++iter;
      require (iter);

      require (HMAC_Update (&ctx, &iter, 1));

      require (HMAC_Final (&ctx, tn, 0));

      int ol = len > md_size ? md_size : len;

      memcpy (okm, tn, ol);

      okm = (void *)(ol + (char *)okm);
      len -= ol;
    }
}

// try to verify all test vectors from the RFC
// since I implemented the hkdf myself, and I am no crypto expert,
// we run verification on every startup.
void
hkdf::verify ()
{
  struct unhex
  {
    u8 *p;
    int l;

    u8 s[256];

    unhex (const char *hs)
    {
      l = 0;
      p = 0;

      if (!hs)
        return;

      p = s;

      while (*hs)
        {
          int d1 = *hs >= '0' && *hs <= '9' ? *hs - '0' : *hs - 'a' + 10; ++hs;
          int d2 = *hs >= '0' && *hs <= '9' ? *hs - '0' : *hs - 'a' + 10; ++hs;

          *p++ = d1 * 16 + d2;
          ++l;
        }

      p = s;
    }
  };

  const struct hkdf_test
  {
     int hash;
     const char *IKM, *salt, *info;
     const char *PRK, *OKM;
  } tests[] = {
    { // 0
      256,
      "0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
      "000102030405060708090a0b0c",
      "f0f1f2f3f4f5f6f7f8f9",
      "077709362c2e32df0ddc3f0dc47bba63"
      "90b6c73bb50f9c3122ec844ad7c2b3e5",
      "3cb25f25faacd57a90434f64d0362f2a"
      "2d2d0a90cf1a5a4c5db02d56ecc4c5bf"
      "34007208d5b887185865"
    }, { // 1
      256,
      "000102030405060708090a0b0c0d0e0f"
      "101112131415161718191a1b1c1d1e1f"
      "202122232425262728292a2b2c2d2e2f"
      "303132333435363738393a3b3c3d3e3f"
      "404142434445464748494a4b4c4d4e4f",
      "606162636465666768696a6b6c6d6e6f"
      "707172737475767778797a7b7c7d7e7f"
      "808182838485868788898a8b8c8d8e8f"
      "909192939495969798999a9b9c9d9e9f"
      "a0a1a2a3a4a5a6a7a8a9aaabacadaeaf",
      "b0b1b2b3b4b5b6b7b8b9babbbcbdbebf"
      "c0c1c2c3c4c5c6c7c8c9cacbcccdcecf"
      "d0d1d2d3d4d5d6d7d8d9dadbdcdddedf"
      "e0e1e2e3e4e5e6e7e8e9eaebecedeeef"
      "f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff",
      "06a6b88c5853361a06104c9ceb35b45c"
      "ef760014904671014a193f40c15fc244",
      "b11e398dc80327a1c8e7f78c596a4934"
      "4f012eda2d4efad8a050cc4c19afa97c"
      "59045a99cac7827271cb41c65e590e09"
      "da3275600c2f09b8367793a9aca3db71"
      "cc30c58179ec3e87c14c01d5c1f3434f"
      "1d87"
    }, { // 2
      256,
      "0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
      "",
      "",
      "19ef24a32c717b167f33a91d6f648bdf"
      "96596776afdb6377ac434c1c293ccb04",
      "8da4e775a563c18f715f802a063c5a31"
      "b8a11f5c5ee1879ec3454e5f3c738d2d"
      "9d201395faa4b61a96c8"
    }, { // 3
      1,
      "0b0b0b0b0b0b0b0b0b0b0b",
      "000102030405060708090a0b0c",
      "f0f1f2f3f4f5f6f7f8f9",
      "9b6c18c432a7bf8f0e71c8eb88f4b30baa2ba243",
      "085a01ea1b10f36933068b56efa5ad81"
      "a4f14b822f5b091568a9cdd4f155fda2"
      "c22e422478d305f3f896"
    }, { // 4
      1,
      "000102030405060708090a0b0c0d0e0f"
      "101112131415161718191a1b1c1d1e1f"
      "202122232425262728292a2b2c2d2e2f"
      "303132333435363738393a3b3c3d3e3f"
      "404142434445464748494a4b4c4d4e4f",
      "606162636465666768696a6b6c6d6e6f"
      "707172737475767778797a7b7c7d7e7f"
      "808182838485868788898a8b8c8d8e8f"
      "909192939495969798999a9b9c9d9e9f"
      "a0a1a2a3a4a5a6a7a8a9aaabacadaeaf",
      "b0b1b2b3b4b5b6b7b8b9babbbcbdbebf"
      "c0c1c2c3c4c5c6c7c8c9cacbcccdcecf"
      "d0d1d2d3d4d5d6d7d8d9dadbdcdddedf"
      "e0e1e2e3e4e5e6e7e8e9eaebecedeeef"
      "f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff",
      "8adae09a2a307059478d309b26c4115a224cfaf6",
      "0bd770a74d1160f7c9f12cd5912a06eb"
      "ff6adcae899d92191fe4305673ba2ffe"
      "8fa3f1a4e5ad79f3f334b3b202b2173c"
      "486ea37ce3d397ed034c7f9dfeb15c5e"
      "927336d0441f4c4300e2cff0d0900b52"
      "d3b4"
    }, { // 5
      1,
      "0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
      "",
      "",
      "da8c8a73c7fa77288ec6f5e7c297786aa0d32d01",
      "0ac1af7002b3d761d1e55298da9d0506"
      "b9ae52057220a306e07b6b87e8df21d0"
      "ea00033de03984d34918"
    }, { // 6
      1,
      "0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c",
      0,
      "",
      "2adccada18779e7c2077ad2eb19d3f3e731385dd",
      "2c91117204d745f3500d636a62f64f0a"
      "b3bae548aa53d423b0d1f27ebba6f5e5"
      "673a081d70cce7acfc48"
    }
  };

  for (int i = 0; i < sizeof (tests) / sizeof (tests[0]); ++i)
    {
      const hkdf_test &test = tests[i];

      unhex salt (test.salt);
      unhex ikm (test.IKM);
      unhex info (test.info);
      unhex prk_correct (test.PRK);
      unhex okm_correct (test.OKM);

      char okm[256];

      hkdf h (salt.p, salt.l, test.hash == 1 ? EVP_sha1 () : EVP_sha256 ());
      h.extract (ikm.p, ikm.l);
      h.extract_done ();
      h.expand (okm, okm_correct.l, info.p, info.l);

      require (!memcmp (h.prk, prk_correct.p, prk_correct.l));
      require (!memcmp (okm  , okm_correct.p, okm_correct.l));
    }
}

Revision:	1.1
Committed:	Tue Jul 16 16:44:36 2013 UTC (10 years, 10 months ago) by root
Content type:	text/plain
Branch:	MAIN
Log Message:	3.x
#	Content
1	/*
2	hkdf.C -- RFC 5869 HKDF implementation
3	Copyright (C) 2013 Marc Lehmann <gvpe@schmorp.de>
4
5	This file is part of GVPE.
6
7	GVPE is free software; you can redistribute it and/or modify it
8	under the terms of the GNU General Public License as published by the
9	Free Software Foundation; either version 3 of the License, or (at your
10	option) any later version.
11
12	This program is distributed in the hope that it will be useful, but
13	WITHOUT ANY WARRANTY; without even the implied warranty of
14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
15	Public License for more details.
16
17	You should have received a copy of the GNU General Public License along
18	with this program; if not, see <http://www.gnu.org/licenses/>.
19
20	Additional permission under GNU GPL version 3 section 7
21
22	If you modify this Program, or any covered work, by linking or
23	combining it with the OpenSSL project's OpenSSL library (or a modified
24	version of that library), containing parts covered by the terms of the
25	OpenSSL or SSLeay licenses, the licensors of this Program grant you
26	additional permission to convey the resulting work. Corresponding
27	Source for a non-source form of such a combination shall include the
28	source code for the parts of OpenSSL used as well as that of the
29	covered work.
30	*/
31
32	#include "config.h"
33
34	#include <cstring>
35
36	#include <openssl/rand.h>
37	#include <openssl/hmac.h>
38
39	#include "util.h"
40	#include "hkdf.h"
41
42	hkdf::hkdf (const void salt, int len, const EVP_MD hash)
43	{
44	HMAC_CTX_init (&ctx);
45
46	if (!salt)
47	{
48	memset (prk, 0, sizeof prk);
49	salt = prk;
50	len = EVP_MD_size (hash);
51	}
52
53	require (HMAC_Init_ex (&ctx, salt, len, hash, 0));
54	}
55
56	hkdf::~hkdf ()
57	{
58	HMAC_CTX_cleanup (&ctx);
59	}
60
61	void
62	hkdf::extract (const void *ikm, int len)
63	{
64	require (HMAC_Update (&ctx, (u8 *)ikm, len));
65	}
66
67	void
68	hkdf::extract_done ()
69	{
70	require (HMAC_Final (&ctx, prk, 0));
71	}
72
73	void
74	hkdf::expand (void okm, int len, const void info, int infolen)
75	{
76	u8 tn[sizeof prk];
77	u8 iter = 0;
78	int md_size = HMAC_size (&ctx);
79
80	while (len)
81	{
82	require (HMAC_Init_ex (&ctx, prk, md_size, 0, 0));
83
84	if (iter)
85	require (HMAC_Update (&ctx, tn, md_size));
86
87	require (HMAC_Update (&ctx, (u8 *)info, infolen));
88
89
90	++iter;
91	require (iter);
92
93	require (HMAC_Update (&ctx, &iter, 1));
94
95	require (HMAC_Final (&ctx, tn, 0));
96
97	int ol = len > md_size ? md_size : len;
98
99	memcpy (okm, tn, ol);
100
101	okm = (void )(ol + (char )okm);
102	len -= ol;
103	}
104	}
105
106	// try to verify all test vectors from the RFC
107	// since I implemented the hkdf myself, and I am no crypto expert,
108	// we run verification on every startup.
109	void
110	hkdf::verify ()
111	{
112	struct unhex
113	{
114	u8 *p;
115	int l;
116
117	u8 s[256];
118
119	unhex (const char *hs)
120	{
121	l = 0;
122	p = 0;
123
124	if (!hs)
125	return;
126
127	p = s;
128
129	while (*hs)
130	{
131	int d1 = hs >= '0' && hs <= '9' ? hs - '0' : hs - 'a' + 10; ++hs;
132	int d2 = hs >= '0' && hs <= '9' ? hs - '0' : hs - 'a' + 10; ++hs;
133
134	p++ = d1 16 + d2;
135	++l;
136	}
137
138	p = s;
139	}
140	};
141
142	const struct hkdf_test
143	{
144	int hash;
145	const char IKM, salt, *info;
146	const char PRK, OKM;
147	} tests[] = {
148	{ // 0
149	256,
150	"0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
151	"000102030405060708090a0b0c",
152	"f0f1f2f3f4f5f6f7f8f9",
153	"077709362c2e32df0ddc3f0dc47bba63"
154	"90b6c73bb50f9c3122ec844ad7c2b3e5",
155	"3cb25f25faacd57a90434f64d0362f2a"
156	"2d2d0a90cf1a5a4c5db02d56ecc4c5bf"
157	"34007208d5b887185865"
158	}, { // 1
159	256,
160	"000102030405060708090a0b0c0d0e0f"
161	"101112131415161718191a1b1c1d1e1f"
162	"202122232425262728292a2b2c2d2e2f"
163	"303132333435363738393a3b3c3d3e3f"
164	"404142434445464748494a4b4c4d4e4f",
165	"606162636465666768696a6b6c6d6e6f"
166	"707172737475767778797a7b7c7d7e7f"
167	"808182838485868788898a8b8c8d8e8f"
168	"909192939495969798999a9b9c9d9e9f"
169	"a0a1a2a3a4a5a6a7a8a9aaabacadaeaf",
170	"b0b1b2b3b4b5b6b7b8b9babbbcbdbebf"
171	"c0c1c2c3c4c5c6c7c8c9cacbcccdcecf"
172	"d0d1d2d3d4d5d6d7d8d9dadbdcdddedf"
173	"e0e1e2e3e4e5e6e7e8e9eaebecedeeef"
174	"f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff",
175	"06a6b88c5853361a06104c9ceb35b45c"
176	"ef760014904671014a193f40c15fc244",
177	"b11e398dc80327a1c8e7f78c596a4934"
178	"4f012eda2d4efad8a050cc4c19afa97c"
179	"59045a99cac7827271cb41c65e590e09"
180	"da3275600c2f09b8367793a9aca3db71"
181	"cc30c58179ec3e87c14c01d5c1f3434f"
182	"1d87"
183	}, { // 2
184	256,
185	"0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
186	"",
187	"",
188	"19ef24a32c717b167f33a91d6f648bdf"
189	"96596776afdb6377ac434c1c293ccb04",
190	"8da4e775a563c18f715f802a063c5a31"
191	"b8a11f5c5ee1879ec3454e5f3c738d2d"
192	"9d201395faa4b61a96c8"
193	}, { // 3
194	1,
195	"0b0b0b0b0b0b0b0b0b0b0b",
196	"000102030405060708090a0b0c",
197	"f0f1f2f3f4f5f6f7f8f9",
198	"9b6c18c432a7bf8f0e71c8eb88f4b30baa2ba243",
199	"085a01ea1b10f36933068b56efa5ad81"
200	"a4f14b822f5b091568a9cdd4f155fda2"
201	"c22e422478d305f3f896"
202	}, { // 4
203	1,
204	"000102030405060708090a0b0c0d0e0f"
205	"101112131415161718191a1b1c1d1e1f"
206	"202122232425262728292a2b2c2d2e2f"
207	"303132333435363738393a3b3c3d3e3f"
208	"404142434445464748494a4b4c4d4e4f",
209	"606162636465666768696a6b6c6d6e6f"
210	"707172737475767778797a7b7c7d7e7f"
211	"808182838485868788898a8b8c8d8e8f"
212	"909192939495969798999a9b9c9d9e9f"
213	"a0a1a2a3a4a5a6a7a8a9aaabacadaeaf",
214	"b0b1b2b3b4b5b6b7b8b9babbbcbdbebf"
215	"c0c1c2c3c4c5c6c7c8c9cacbcccdcecf"
216	"d0d1d2d3d4d5d6d7d8d9dadbdcdddedf"
217	"e0e1e2e3e4e5e6e7e8e9eaebecedeeef"
218	"f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff",
219	"8adae09a2a307059478d309b26c4115a224cfaf6",
220	"0bd770a74d1160f7c9f12cd5912a06eb"
221	"ff6adcae899d92191fe4305673ba2ffe"
222	"8fa3f1a4e5ad79f3f334b3b202b2173c"
223	"486ea37ce3d397ed034c7f9dfeb15c5e"
224	"927336d0441f4c4300e2cff0d0900b52"
225	"d3b4"
226	}, { // 5
227	1,
228	"0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
229	"",
230	"",
231	"da8c8a73c7fa77288ec6f5e7c297786aa0d32d01",
232	"0ac1af7002b3d761d1e55298da9d0506"
233	"b9ae52057220a306e07b6b87e8df21d0"
234	"ea00033de03984d34918"
235	}, { // 6
236	1,
237	"0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c",
238	0,
239	"",
240	"2adccada18779e7c2077ad2eb19d3f3e731385dd",
241	"2c91117204d745f3500d636a62f64f0a"
242	"b3bae548aa53d423b0d1f27ebba6f5e5"
243	"673a081d70cce7acfc48"
244	}
245	};
246
247	for (int i = 0; i < sizeof (tests) / sizeof (tests[0]); ++i)
248	{
249	const hkdf_test &test = tests[i];
250
251	unhex salt (test.salt);
252	unhex ikm (test.IKM);
253	unhex info (test.info);
254	unhex prk_correct (test.PRK);
255	unhex okm_correct (test.OKM);
256
257	char okm[256];
258
259	hkdf h (salt.p, salt.l, test.hash == 1 ? EVP_sha1 () : EVP_sha256 ());
260	h.extract (ikm.p, ikm.l);
261	h.extract_done ();
262	h.expand (okm, okm_correct.l, info.p, info.l);
263
264	require (!memcmp (h.prk, prk_correct.p, prk_correct.l));
265	require (!memcmp (okm , okm_correct.p, okm_correct.l));
266	}
267	}
268