gvpe/src/hkdf.C

/*
    hkdf.C -- RFC 5869 HKDF implementation
    Copyright (C) 2013,2016 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 "crypto.h"
#include "util.h"
#include "hkdf.h"

hkdf::hkdf (const void *salt, int len, const EVP_MD *xtr_hash)
: salt (salt), salt_len (len)
{
  ctx.init (salt, salt_len, xtr_hash);
}

void
hkdf::extract (const void *ikm, int len)
{
  ctx.add (ikm, len);
}

void
hkdf::extract_done (const EVP_MD *prf_hash)
{
  ctx.digest (prk);
  ctx.init (salt, salt_len, prf_hash);
}

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

  while (len)
    {
      ctx.init (prk, md_size);

      if (iter)
        ctx.add (tn, md_size);

      ctx.add (info, infolen);

      ++iter;
      require (iter);

      ctx.add (&iter, 1);
      ctx.digest (tn);

      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 = s;

      if (!hs)
        return;

      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:	1.6
Committed:	Thu Jun 30 16:31:00 2016 UTC (7 years, 10 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rel-3_0, HEAD
Changes since 1.5:	+8 -4 lines
Log Message:	work around https://github.com/openssl/openssl/commit/4b464e7b46682f568a5df550426b0cf4b22e2485
#	Content
1	/*
2	hkdf.C -- RFC 5869 HKDF implementation
3	Copyright (C) 2013,2016 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 "crypto.h"
41	#include "util.h"
42	#include "hkdf.h"
43
44	hkdf::hkdf (const void salt, int len, const EVP_MD xtr_hash)
45	: salt (salt), salt_len (len)
46	{
47	ctx.init (salt, salt_len, xtr_hash);
48	}
49
50	void
51	hkdf::extract (const void *ikm, int len)
52	{
53	ctx.add (ikm, len);
54	}
55
56	void
57	hkdf::extract_done (const EVP_MD *prf_hash)
58	{
59	ctx.digest (prk);
60	ctx.init (salt, salt_len, prf_hash);
61	}
62
63	void
64	hkdf::expand (void okm, int len, const void info, int infolen)
65	{
66	u8 tn[sizeof prk];
67	u8 iter = 0;
68	int md_size = ctx.size ();
69
70	while (len)
71	{
72	ctx.init (prk, md_size);
73
74	if (iter)
75	ctx.add (tn, md_size);
76
77	ctx.add (info, infolen);
78
79	++iter;
80	require (iter);
81
82	ctx.add (&iter, 1);
83	ctx.digest (tn);
84
85	int ol = len > md_size ? md_size : len;
86
87	memcpy (okm, tn, ol);
88
89	okm = (void )(ol + (char )okm);
90	len -= ol;
91	}
92	}
93
94	// try to verify all test vectors from the RFC
95	// since I implemented the hkdf myself, and I am no crypto expert,
96	// we run verification on every startup.
97	void
98	hkdf::verify ()
99	{
100	struct unhex
101	{
102	u8 *p;
103	int l;
104
105	u8 s[256];
106
107	unhex (const char *hs)
108	{
109	l = 0;
110	p = s;
111
112	if (!hs)
113	return;
114
115	while (*hs)
116	{
117	int d1 = hs >= '0' && hs <= '9' ? hs - '0' : hs - 'a' + 10; ++hs;
118	int d2 = hs >= '0' && hs <= '9' ? hs - '0' : hs - 'a' + 10; ++hs;
119
120	p++ = d1 16 + d2;
121	++l;
122	}
123
124	p = s;
125	}
126	};
127
128	const struct hkdf_test
129	{
130	int hash;
131	const char IKM, salt, *info;
132	const char PRK, OKM;
133	} tests[] = {
134	{ // 0
135	256,
136	"0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
137	"000102030405060708090a0b0c",
138	"f0f1f2f3f4f5f6f7f8f9",
139	"077709362c2e32df0ddc3f0dc47bba63"
140	"90b6c73bb50f9c3122ec844ad7c2b3e5",
141	"3cb25f25faacd57a90434f64d0362f2a"
142	"2d2d0a90cf1a5a4c5db02d56ecc4c5bf"
143	"34007208d5b887185865"
144	}, { // 1
145	256,
146	"000102030405060708090a0b0c0d0e0f"
147	"101112131415161718191a1b1c1d1e1f"
148	"202122232425262728292a2b2c2d2e2f"
149	"303132333435363738393a3b3c3d3e3f"
150	"404142434445464748494a4b4c4d4e4f",
151	"606162636465666768696a6b6c6d6e6f"
152	"707172737475767778797a7b7c7d7e7f"
153	"808182838485868788898a8b8c8d8e8f"
154	"909192939495969798999a9b9c9d9e9f"
155	"a0a1a2a3a4a5a6a7a8a9aaabacadaeaf",
156	"b0b1b2b3b4b5b6b7b8b9babbbcbdbebf"
157	"c0c1c2c3c4c5c6c7c8c9cacbcccdcecf"
158	"d0d1d2d3d4d5d6d7d8d9dadbdcdddedf"
159	"e0e1e2e3e4e5e6e7e8e9eaebecedeeef"
160	"f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff",
161	"06a6b88c5853361a06104c9ceb35b45c"
162	"ef760014904671014a193f40c15fc244",
163	"b11e398dc80327a1c8e7f78c596a4934"
164	"4f012eda2d4efad8a050cc4c19afa97c"
165	"59045a99cac7827271cb41c65e590e09"
166	"da3275600c2f09b8367793a9aca3db71"
167	"cc30c58179ec3e87c14c01d5c1f3434f"
168	"1d87"
169	}, { // 2
170	256,
171	"0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
172	"",
173	"",
174	"19ef24a32c717b167f33a91d6f648bdf"
175	"96596776afdb6377ac434c1c293ccb04",
176	"8da4e775a563c18f715f802a063c5a31"
177	"b8a11f5c5ee1879ec3454e5f3c738d2d"
178	"9d201395faa4b61a96c8"
179	}, { // 3
180	1,
181	"0b0b0b0b0b0b0b0b0b0b0b",
182	"000102030405060708090a0b0c",
183	"f0f1f2f3f4f5f6f7f8f9",
184	"9b6c18c432a7bf8f0e71c8eb88f4b30baa2ba243",
185	"085a01ea1b10f36933068b56efa5ad81"
186	"a4f14b822f5b091568a9cdd4f155fda2"
187	"c22e422478d305f3f896"
188	}, { // 4
189	1,
190	"000102030405060708090a0b0c0d0e0f"
191	"101112131415161718191a1b1c1d1e1f"
192	"202122232425262728292a2b2c2d2e2f"
193	"303132333435363738393a3b3c3d3e3f"
194	"404142434445464748494a4b4c4d4e4f",
195	"606162636465666768696a6b6c6d6e6f"
196	"707172737475767778797a7b7c7d7e7f"
197	"808182838485868788898a8b8c8d8e8f"
198	"909192939495969798999a9b9c9d9e9f"
199	"a0a1a2a3a4a5a6a7a8a9aaabacadaeaf",
200	"b0b1b2b3b4b5b6b7b8b9babbbcbdbebf"
201	"c0c1c2c3c4c5c6c7c8c9cacbcccdcecf"
202	"d0d1d2d3d4d5d6d7d8d9dadbdcdddedf"
203	"e0e1e2e3e4e5e6e7e8e9eaebecedeeef"
204	"f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff",
205	"8adae09a2a307059478d309b26c4115a224cfaf6",
206	"0bd770a74d1160f7c9f12cd5912a06eb"
207	"ff6adcae899d92191fe4305673ba2ffe"
208	"8fa3f1a4e5ad79f3f334b3b202b2173c"
209	"486ea37ce3d397ed034c7f9dfeb15c5e"
210	"927336d0441f4c4300e2cff0d0900b52"
211	"d3b4"
212	}, { // 5
213	1,
214	"0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
215	"",
216	"",
217	"da8c8a73c7fa77288ec6f5e7c297786aa0d32d01",
218	"0ac1af7002b3d761d1e55298da9d0506"
219	"b9ae52057220a306e07b6b87e8df21d0"
220	"ea00033de03984d34918"
221	}, { // 6
222	1,
223	"0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c",
224	0,
225	"",
226	"2adccada18779e7c2077ad2eb19d3f3e731385dd",
227	"2c91117204d745f3500d636a62f64f0a"
228	"b3bae548aa53d423b0d1f27ebba6f5e5"
229	"673a081d70cce7acfc48"
230	}
231	};
232
233	for (int i = 0; i < sizeof (tests) / sizeof (tests[0]); ++i)
234	{
235	const hkdf_test &test = tests[i];
236
237	unhex salt (test.salt);
238	unhex ikm (test.IKM);
239	unhex info (test.info);
240	unhex prk_correct (test.PRK);
241	unhex okm_correct (test.OKM);
242
243	char okm[256];
244
245	hkdf h (salt.p, salt.l, test.hash == 1 ? EVP_sha1 () : EVP_sha256 ());
246	h.extract (ikm.p, ikm.l);
247	h.extract_done ();
248	h.expand (okm, okm_correct.l, info.p, info.l);
249
250	require (!memcmp (h.prk, prk_correct.p, prk_correct.l));
251	require (!memcmp (okm , okm_correct.p, okm_correct.l));
252	}
253	}
254