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
#	User	Rev	Content
1	root	1.1	/*
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