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"

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 (0, 0, 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 = 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:	1.5
Committed:	Thu Jun 30 11:43:38 2016 UTC (7 years, 11 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.4:	+11 -37 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	/*
2			hkdf.C -- RFC 5869 HKDF implementation
3	root	1.5	Copyright (C) 2013,2016 Marc Lehmann <gvpe@schmorp.de>
4	root	1.1
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	root	1.3	#include <openssl/opensslv.h>
37	root	1.1	#include <openssl/rand.h>
38			#include <openssl/hmac.h>
39
40	root	1.5	#include "crypto.h"
41	root	1.1	#include "util.h"
42			#include "hkdf.h"
43
44			void
45			hkdf::extract (const void *ikm, int len)
46			{
47	root	1.5	ctx.add (ikm, len);
48	root	1.1	}
49
50			void
51	root	1.2	hkdf::extract_done (const EVP_MD *prf_hash)
52	root	1.1	{
53	root	1.5	ctx.digest (prk);
54			ctx.init (0, 0, prf_hash);
55	root	1.1	}
56
57			void
58			hkdf::expand (void okm, int len, const void info, int infolen)
59			{
60			u8 tn[sizeof prk];
61			u8 iter = 0;
62	root	1.5	int md_size = ctx.size ();
63	root	1.1
64			while (len)
65			{
66	root	1.5	ctx.init (prk, md_size);
67	root	1.1
68			if (iter)
69	root	1.5	ctx.add (tn, md_size);
70	root	1.1
71	root	1.5	ctx.add (info, infolen);
72	root	1.1
73			++iter;
74			require (iter);
75
76	root	1.5	ctx.add (&iter, 1);
77			ctx.digest (tn);
78	root	1.1
79			int ol = len > md_size ? md_size : len;
80
81			memcpy (okm, tn, ol);
82
83			okm = (void )(ol + (char )okm);
84			len -= ol;
85			}
86			}
87
88			// try to verify all test vectors from the RFC
89			// since I implemented the hkdf myself, and I am no crypto expert,
90			// we run verification on every startup.
91			void
92			hkdf::verify ()
93			{
94			struct unhex
95			{
96			u8 *p;
97			int l;
98
99			u8 s[256];
100
101			unhex (const char *hs)
102			{
103			l = 0;
104			p = 0;
105
106			if (!hs)
107			return;
108
109			p = s;
110
111			while (*hs)
112			{
113			int d1 = hs >= '0' && hs <= '9' ? hs - '0' : hs - 'a' + 10; ++hs;
114			int d2 = hs >= '0' && hs <= '9' ? hs - '0' : hs - 'a' + 10; ++hs;
115
116			p++ = d1 16 + d2;
117			++l;
118			}
119
120			p = s;
121			}
122			};
123
124			const struct hkdf_test
125			{
126			int hash;
127			const char IKM, salt, *info;
128			const char PRK, OKM;
129			} tests[] = {
130			{ // 0
131			256,
132			"0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
133			"000102030405060708090a0b0c",
134			"f0f1f2f3f4f5f6f7f8f9",
135			"077709362c2e32df0ddc3f0dc47bba63"
136			"90b6c73bb50f9c3122ec844ad7c2b3e5",
137			"3cb25f25faacd57a90434f64d0362f2a"
138			"2d2d0a90cf1a5a4c5db02d56ecc4c5bf"
139			"34007208d5b887185865"
140			}, { // 1
141			256,
142			"000102030405060708090a0b0c0d0e0f"
143			"101112131415161718191a1b1c1d1e1f"
144			"202122232425262728292a2b2c2d2e2f"
145			"303132333435363738393a3b3c3d3e3f"
146			"404142434445464748494a4b4c4d4e4f",
147			"606162636465666768696a6b6c6d6e6f"
148			"707172737475767778797a7b7c7d7e7f"
149			"808182838485868788898a8b8c8d8e8f"
150			"909192939495969798999a9b9c9d9e9f"
151			"a0a1a2a3a4a5a6a7a8a9aaabacadaeaf",
152			"b0b1b2b3b4b5b6b7b8b9babbbcbdbebf"
153			"c0c1c2c3c4c5c6c7c8c9cacbcccdcecf"
154			"d0d1d2d3d4d5d6d7d8d9dadbdcdddedf"
155			"e0e1e2e3e4e5e6e7e8e9eaebecedeeef"
156			"f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff",
157			"06a6b88c5853361a06104c9ceb35b45c"
158			"ef760014904671014a193f40c15fc244",
159			"b11e398dc80327a1c8e7f78c596a4934"
160			"4f012eda2d4efad8a050cc4c19afa97c"
161			"59045a99cac7827271cb41c65e590e09"
162			"da3275600c2f09b8367793a9aca3db71"
163			"cc30c58179ec3e87c14c01d5c1f3434f"
164			"1d87"
165			}, { // 2
166			256,
167			"0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
168			"",
169			"",
170			"19ef24a32c717b167f33a91d6f648bdf"
171			"96596776afdb6377ac434c1c293ccb04",
172			"8da4e775a563c18f715f802a063c5a31"
173			"b8a11f5c5ee1879ec3454e5f3c738d2d"
174			"9d201395faa4b61a96c8"
175			}, { // 3
176			1,
177			"0b0b0b0b0b0b0b0b0b0b0b",
178			"000102030405060708090a0b0c",
179			"f0f1f2f3f4f5f6f7f8f9",
180			"9b6c18c432a7bf8f0e71c8eb88f4b30baa2ba243",
181			"085a01ea1b10f36933068b56efa5ad81"
182			"a4f14b822f5b091568a9cdd4f155fda2"
183			"c22e422478d305f3f896"
184			}, { // 4
185			1,
186			"000102030405060708090a0b0c0d0e0f"
187			"101112131415161718191a1b1c1d1e1f"
188			"202122232425262728292a2b2c2d2e2f"
189			"303132333435363738393a3b3c3d3e3f"
190			"404142434445464748494a4b4c4d4e4f",
191			"606162636465666768696a6b6c6d6e6f"
192			"707172737475767778797a7b7c7d7e7f"
193			"808182838485868788898a8b8c8d8e8f"
194			"909192939495969798999a9b9c9d9e9f"
195			"a0a1a2a3a4a5a6a7a8a9aaabacadaeaf",
196			"b0b1b2b3b4b5b6b7b8b9babbbcbdbebf"
197			"c0c1c2c3c4c5c6c7c8c9cacbcccdcecf"
198			"d0d1d2d3d4d5d6d7d8d9dadbdcdddedf"
199			"e0e1e2e3e4e5e6e7e8e9eaebecedeeef"
200			"f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff",
201			"8adae09a2a307059478d309b26c4115a224cfaf6",
202			"0bd770a74d1160f7c9f12cd5912a06eb"
203			"ff6adcae899d92191fe4305673ba2ffe"
204			"8fa3f1a4e5ad79f3f334b3b202b2173c"
205			"486ea37ce3d397ed034c7f9dfeb15c5e"
206			"927336d0441f4c4300e2cff0d0900b52"
207			"d3b4"
208			}, { // 5
209			1,
210			"0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b",
211			"",
212			"",
213			"da8c8a73c7fa77288ec6f5e7c297786aa0d32d01",
214			"0ac1af7002b3d761d1e55298da9d0506"
215			"b9ae52057220a306e07b6b87e8df21d0"
216			"ea00033de03984d34918"
217			}, { // 6
218			1,
219			"0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c0c",
220			0,
221			"",
222			"2adccada18779e7c2077ad2eb19d3f3e731385dd",
223			"2c91117204d745f3500d636a62f64f0a"
224			"b3bae548aa53d423b0d1f27ebba6f5e5"
225			"673a081d70cce7acfc48"
226			}
227			};
228
229			for (int i = 0; i < sizeof (tests) / sizeof (tests[0]); ++i)
230			{
231			const hkdf_test &test = tests[i];
232
233			unhex salt (test.salt);
234			unhex ikm (test.IKM);
235			unhex info (test.info);
236			unhex prk_correct (test.PRK);
237			unhex okm_correct (test.OKM);
238
239			char okm[256];
240
241			hkdf h (salt.p, salt.l, test.hash == 1 ? EVP_sha1 () : EVP_sha256 ());
242			h.extract (ikm.p, ikm.l);
243			h.extract_done ();
244			h.expand (okm, okm_correct.l, info.p, info.l);
245
246			require (!memcmp (h.prk, prk_correct.p, prk_correct.l));
247			require (!memcmp (okm , okm_correct.p, okm_correct.l));
248			}
249			}
250