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

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

// openssl 0.9.8 compatibility
#if OPENSSL_VERSION_NUMBER < 0x10100000
  #define require101(exp) exp
#else
  #define require101(exp) equire (exp)
#endif

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

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

  require101 (HMAC_Init_ex (&ctx, salt, len, xtr_hash, 0));
}

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

void
hkdf::extract (const void *ikm, int len)
{
  require101 (HMAC_Update (&ctx, (u8 *)ikm, len));
}

void
hkdf::extract_done (const EVP_MD *prf_hash)
{
  require101 (HMAC_Final (&ctx, prk, 0));
  require101 (HMAC_Init_ex (&ctx, 0, 0, prf_hash, 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)
    {
      require101 (HMAC_Init_ex (&ctx, prk, md_size, 0, 0));

      if (iter)
        require101 (HMAC_Update (&ctx, tn, md_size));

      require101 (HMAC_Update (&ctx, (u8 *)info, infolen));

      ++iter;
      require (iter);

      require101 (HMAC_Update (&ctx, &iter, 1));

      require101 (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:	1.3
Committed:	Fri Sep 20 11:57:03 2013 UTC (10 years, 8 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.2:	+17 -10 lines
Log Message:	* empty log message *
#	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/opensslv.h>
37	#include <openssl/rand.h>
38	#include <openssl/hmac.h>
39
40	#include "util.h"
41	#include "hkdf.h"
42
43	// openssl 0.9.8 compatibility
44	#if OPENSSL_VERSION_NUMBER < 0x10100000
45	#define require101(exp) exp
46	#else
47	#define require101(exp) equire (exp)
48	#endif
49
50	hkdf::hkdf (const void salt, int len, const EVP_MD xtr_hash)
51	{
52	HMAC_CTX_init (&ctx);
53
54	if (!salt)
55	{
56	memset (prk, 0, sizeof prk);
57	salt = prk;
58	len = EVP_MD_size (xtr_hash);
59	}
60
61	require101 (HMAC_Init_ex (&ctx, salt, len, xtr_hash, 0));
62	}
63
64	hkdf::~hkdf ()
65	{
66	HMAC_CTX_cleanup (&ctx);
67	}
68
69	void
70	hkdf::extract (const void *ikm, int len)
71	{
72	require101 (HMAC_Update (&ctx, (u8 *)ikm, len));
73	}
74
75	void
76	hkdf::extract_done (const EVP_MD *prf_hash)
77	{
78	require101 (HMAC_Final (&ctx, prk, 0));
79	require101 (HMAC_Init_ex (&ctx, 0, 0, prf_hash, 0));
80	}
81
82	void
83	hkdf::expand (void okm, int len, const void info, int infolen)
84	{
85	u8 tn[sizeof prk];
86	u8 iter = 0;
87	int md_size = HMAC_size (&ctx);
88
89	while (len)
90	{
91	require101 (HMAC_Init_ex (&ctx, prk, md_size, 0, 0));
92
93	if (iter)
94	require101 (HMAC_Update (&ctx, tn, md_size));
95
96	require101 (HMAC_Update (&ctx, (u8 *)info, infolen));
97
98	++iter;
99	require (iter);
100
101	require101 (HMAC_Update (&ctx, &iter, 1));
102
103	require101 (HMAC_Final (&ctx, tn, 0));
104
105	int ol = len > md_size ? md_size : len;
106
107	memcpy (okm, tn, ol);
108
109	okm = (void )(ol + (char )okm);
110	len -= ol;
111	}
112	}
113
114	// try to verify all test vectors from the RFC
115	// since I implemented the hkdf myself, and I am no crypto expert,
116	// we run verification on every startup.
117	void
118	hkdf::verify ()
119	{
120	struct unhex
121	{
122	u8 *p;
123	int l;
124
125	u8 s[256];
126
127	unhex (const char *hs)
128	{
129	l = 0;
130	p = 0;
131
132	if (!hs)
133	return;
134
135	p = s;
136
137	while (*hs)
138	{
139	int d1 = hs >= '0' && hs <= '9' ? hs - '0' : hs - 'a' + 10; ++hs;
140	int d2 = hs >= '0' && hs <= '9' ? hs - '0' : hs - 'a' + 10; ++hs;
141
142	p++ = d1 16 + d2;
143	++l;
144	}
145
146	p = s;
147	}
148	};
149
150	const struct hkdf_test
151	{
152	int hash;
153	const char IKM, salt, *info;
154	const char PRK, OKM;
155	} tests[] = {
156	{ // 0
157	256,
158	"0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
159	"000102030405060708090a0b0c",
160	"f0f1f2f3f4f5f6f7f8f9",
161	"077709362c2e32df0ddc3f0dc47bba63"
162	"90b6c73bb50f9c3122ec844ad7c2b3e5",
163	"3cb25f25faacd57a90434f64d0362f2a"
164	"2d2d0a90cf1a5a4c5db02d56ecc4c5bf"
165	"34007208d5b887185865"
166	}, { // 1
167	256,
168	"000102030405060708090a0b0c0d0e0f"
169	"101112131415161718191a1b1c1d1e1f"
170	"202122232425262728292a2b2c2d2e2f"
171	"303132333435363738393a3b3c3d3e3f"
172	"404142434445464748494a4b4c4d4e4f",
173	"606162636465666768696a6b6c6d6e6f"
174	"707172737475767778797a7b7c7d7e7f"
175	"808182838485868788898a8b8c8d8e8f"
176	"909192939495969798999a9b9c9d9e9f"
177	"a0a1a2a3a4a5a6a7a8a9aaabacadaeaf",
178	"b0b1b2b3b4b5b6b7b8b9babbbcbdbebf"
179	"c0c1c2c3c4c5c6c7c8c9cacbcccdcecf"
180	"d0d1d2d3d4d5d6d7d8d9dadbdcdddedf"
181	"e0e1e2e3e4e5e6e7e8e9eaebecedeeef"
182	"f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff",
183	"06a6b88c5853361a06104c9ceb35b45c"
184	"ef760014904671014a193f40c15fc244",
185	"b11e398dc80327a1c8e7f78c596a4934"
186	"4f012eda2d4efad8a050cc4c19afa97c"
187	"59045a99cac7827271cb41c65e590e09"
188	"da3275600c2f09b8367793a9aca3db71"
189	"cc30c58179ec3e87c14c01d5c1f3434f"
190	"1d87"
191	}, { // 2
192	256,
193	"0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
194	"",
195	"",
196	"19ef24a32c717b167f33a91d6f648bdf"
197	"96596776afdb6377ac434c1c293ccb04",
198	"8da4e775a563c18f715f802a063c5a31"
199	"b8a11f5c5ee1879ec3454e5f3c738d2d"
200	"9d201395faa4b61a96c8"
201	}, { // 3
202	1,
203	"0b0b0b0b0b0b0b0b0b0b0b",
204	"000102030405060708090a0b0c",
205	"f0f1f2f3f4f5f6f7f8f9",
206	"9b6c18c432a7bf8f0e71c8eb88f4b30baa2ba243",
207	"085a01ea1b10f36933068b56efa5ad81"
208	"a4f14b822f5b091568a9cdd4f155fda2"
209	"c22e422478d305f3f896"
210	}, { // 4
211	1,
212	"000102030405060708090a0b0c0d0e0f"
213	"101112131415161718191a1b1c1d1e1f"
214	"202122232425262728292a2b2c2d2e2f"
215	"303132333435363738393a3b3c3d3e3f"
216	"404142434445464748494a4b4c4d4e4f",
217	"606162636465666768696a6b6c6d6e6f"
218	"707172737475767778797a7b7c7d7e7f"
219	"808182838485868788898a8b8c8d8e8f"
220	"909192939495969798999a9b9c9d9e9f"
221	"a0a1a2a3a4a5a6a7a8a9aaabacadaeaf",
222	"b0b1b2b3b4b5b6b7b8b9babbbcbdbebf"
223	"c0c1c2c3c4c5c6c7c8c9cacbcccdcecf"
224	"d0d1d2d3d4d5d6d7d8d9dadbdcdddedf"
225	"e0e1e2e3e4e5e6e7e8e9eaebecedeeef"
226	"f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff",
227	"8adae09a2a307059478d309b26c4115a224cfaf6",
228	"0bd770a74d1160f7c9f12cd5912a06eb"
229	"ff6adcae899d92191fe4305673ba2ffe"
230	"8fa3f1a4e5ad79f3f334b3b202b2173c"
231	"486ea37ce3d397ed034c7f9dfeb15c5e"
232	"927336d0441f4c4300e2cff0d0900b52"
233	"d3b4"
234	}, { // 5
235	1,
236	"0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
237	"",
238	"",
239	"da8c8a73c7fa77288ec6f5e7c297786aa0d32d01",
240	"0ac1af7002b3d761d1e55298da9d0506"
241	"b9ae52057220a306e07b6b87e8df21d0"
242	"ea00033de03984d34918"
243	}, { // 6
244	1,
245	"0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c",
246	0,
247	"",
248	"2adccada18779e7c2077ad2eb19d3f3e731385dd",
249	"2c91117204d745f3500d636a62f64f0a"
250	"b3bae548aa53d423b0d1f27ebba6f5e5"
251	"673a081d70cce7acfc48"
252	}
253	};
254
255	for (int i = 0; i < sizeof (tests) / sizeof (tests[0]); ++i)
256	{
257	const hkdf_test &test = tests[i];
258
259	unhex salt (test.salt);
260	unhex ikm (test.IKM);
261	unhex info (test.info);
262	unhex prk_correct (test.PRK);
263	unhex okm_correct (test.OKM);
264
265	char okm[256];
266
267	hkdf h (salt.p, salt.l, test.hash == 1 ? EVP_sha1 () : EVP_sha256 ());
268	h.extract (ikm.p, ikm.l);
269	h.extract_done ();
270	h.expand (okm, okm_correct.l, info.p, info.l);
271
272	require (!memcmp (h.prk, prk_correct.p, prk_correct.l));
273	require (!memcmp (okm , okm_correct.p, okm_correct.l));
274	}
275	}
276