1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Implementation of HKDF ("HMAC-based Extract-and-Expand Key Derivation
4 * Function"), aka RFC 5869. See also the original paper (Krawczyk 2010):
5 * "Cryptographic Extraction and Key Derivation: The HKDF Scheme".
6 *
7 * Copyright 2019 Google LLC
8 */
9
10#include <crypto/internal/hash.h>
11#include <crypto/sha2.h>
12#include <crypto/hkdf.h>
13#include <linux/module.h>
14
15/*
16 * HKDF consists of two steps:
17 *
18 * 1. HKDF-Extract: extract a pseudorandom key from the input keying material
19 * and optional salt.
20 * 2. HKDF-Expand: expand the pseudorandom key into output keying material of
21 * any length, parameterized by an application-specific info string.
22 *
23 */
24
25/**
26 * hkdf_extract - HKDF-Extract (RFC 5869 section 2.2)
27 * @hmac_tfm: an HMAC transform using the hash function desired for HKDF. The
28 * caller is responsible for setting the @prk afterwards.
29 * @ikm: input keying material
30 * @ikmlen: length of @ikm
31 * @salt: input salt value
32 * @saltlen: length of @salt
33 * @prk: resulting pseudorandom key
34 *
35 * Extracts a pseudorandom key @prk from the input keying material
36 * @ikm with length @ikmlen and salt @salt with length @saltlen.
37 * The length of @prk is given by the digest size of @hmac_tfm.
38 * For an 'unsalted' version of HKDF-Extract @salt must be set
39 * to all zeroes and @saltlen must be set to the length of @prk.
40 *
41 * Returns 0 on success with the pseudorandom key stored in @prk,
42 * or a negative errno value otherwise.
43 */
44int hkdf_extract(struct crypto_shash *hmac_tfm, const u8 *ikm,
45 unsigned int ikmlen, const u8 *salt, unsigned int saltlen,
46 u8 *prk)
47{
48 int err;
49
50 err = crypto_shash_setkey(tfm: hmac_tfm, key: salt, keylen: saltlen);
51 if (!err)
52 err = crypto_shash_tfm_digest(tfm: hmac_tfm, data: ikm, len: ikmlen, out: prk);
53
54 return err;
55}
56EXPORT_SYMBOL_GPL(hkdf_extract);
57
58/**
59 * hkdf_expand - HKDF-Expand (RFC 5869 section 2.3)
60 * @hmac_tfm: hash context keyed with pseudorandom key
61 * @info: application-specific information
62 * @infolen: length of @info
63 * @okm: output keying material
64 * @okmlen: length of @okm
65 *
66 * This expands the pseudorandom key, which was already keyed into @hmac_tfm,
67 * into @okmlen bytes of output keying material parameterized by the
68 * application-specific @info of length @infolen bytes.
69 * This is thread-safe and may be called by multiple threads in parallel.
70 *
71 * Returns 0 on success with output keying material stored in @okm,
72 * or a negative errno value otherwise.
73 */
74int hkdf_expand(struct crypto_shash *hmac_tfm,
75 const u8 *info, unsigned int infolen,
76 u8 *okm, unsigned int okmlen)
77{
78 SHASH_DESC_ON_STACK(desc, hmac_tfm);
79 unsigned int i, hashlen = crypto_shash_digestsize(tfm: hmac_tfm);
80 int err;
81 const u8 *prev = NULL;
82 u8 counter = 1;
83 u8 tmp[HASH_MAX_DIGESTSIZE] = {};
84
85 if (WARN_ON(okmlen > 255 * hashlen))
86 return -EINVAL;
87
88 desc->tfm = hmac_tfm;
89
90 for (i = 0; i < okmlen; i += hashlen) {
91 err = crypto_shash_init(desc);
92 if (err)
93 goto out;
94
95 if (prev) {
96 err = crypto_shash_update(desc, data: prev, len: hashlen);
97 if (err)
98 goto out;
99 }
100
101 if (infolen) {
102 err = crypto_shash_update(desc, data: info, len: infolen);
103 if (err)
104 goto out;
105 }
106
107 BUILD_BUG_ON(sizeof(counter) != 1);
108 if (okmlen - i < hashlen) {
109 err = crypto_shash_finup(desc, data: &counter, len: 1, out: tmp);
110 if (err)
111 goto out;
112 memcpy(&okm[i], tmp, okmlen - i);
113 memzero_explicit(s: tmp, count: sizeof(tmp));
114 } else {
115 err = crypto_shash_finup(desc, data: &counter, len: 1, out: &okm[i]);
116 if (err)
117 goto out;
118 }
119 counter++;
120 prev = &okm[i];
121 }
122 err = 0;
123out:
124 if (unlikely(err))
125 memzero_explicit(s: okm, count: okmlen); /* so caller doesn't need to */
126 shash_desc_zero(desc);
127 memzero_explicit(s: tmp, HASH_MAX_DIGESTSIZE);
128 return err;
129}
130EXPORT_SYMBOL_GPL(hkdf_expand);
131
132struct hkdf_testvec {
133 const char *test;
134 const u8 *ikm;
135 const u8 *salt;
136 const u8 *info;
137 const u8 *prk;
138 const u8 *okm;
139 u16 ikm_size;
140 u16 salt_size;
141 u16 info_size;
142 u16 prk_size;
143 u16 okm_size;
144};
145
146/*
147 * HKDF test vectors from RFC5869
148 *
149 * Additional HKDF test vectors from
150 * https://github.com/brycx/Test-Vector-Generation/blob/master/HKDF/hkdf-hmac-sha2-test-vectors.md
151 */
152static const struct hkdf_testvec hkdf_sha256_tv[] = {
153 {
154 .test = "basic hdkf test",
155 .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b"
156 "\x0b\x0b\x0b\x0b\x0b\x0b",
157 .ikm_size = 22,
158 .salt = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c",
159 .salt_size = 13,
160 .info = "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9",
161 .info_size = 10,
162 .prk = "\x07\x77\x09\x36\x2c\x2e\x32\xdf\x0d\xdc\x3f\x0d\xc4\x7b\xba\x63"
163 "\x90\xb6\xc7\x3b\xb5\x0f\x9c\x31\x22\xec\x84\x4a\xd7\xc2\xb3\xe5",
164 .prk_size = 32,
165 .okm = "\x3c\xb2\x5f\x25\xfa\xac\xd5\x7a\x90\x43\x4f\x64\xd0\x36\x2f\x2a"
166 "\x2d\x2d\x0a\x90\xcf\x1a\x5a\x4c\x5d\xb0\x2d\x56\xec\xc4\xc5\xbf"
167 "\x34\x00\x72\x08\xd5\xb8\x87\x18\x58\x65",
168 .okm_size = 42,
169 }, {
170 .test = "hkdf test with long input",
171 .ikm = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
172 "\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"
173 "\x20\x21\x22\x23\x24\x25\x26\x27\x28\x29\x2a\x2b\x2c\x2d\x2e\x2f"
174 "\x30\x31\x32\x33\x34\x35\x36\x37\x38\x39\x3a\x3b\x3c\x3d\x3e\x3f"
175 "\x40\x41\x42\x43\x44\x45\x46\x47\x48\x49\x4a\x4b\x4c\x4d\x4e\x4f",
176 .ikm_size = 80,
177 .salt = "\x60\x61\x62\x63\x64\x65\x66\x67\x68\x69\x6a\x6b\x6c\x6d\x6e\x6f"
178 "\x70\x71\x72\x73\x74\x75\x76\x77\x78\x79\x7a\x7b\x7c\x7d\x7e\x7f"
179 "\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f"
180 "\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f"
181 "\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf",
182 .salt_size = 80,
183 .info = "\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf"
184 "\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf"
185 "\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf"
186 "\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef"
187 "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff",
188 .info_size = 80,
189 .prk = "\x06\xa6\xb8\x8c\x58\x53\x36\x1a\x06\x10\x4c\x9c\xeb\x35\xb4\x5c"
190 "\xef\x76\x00\x14\x90\x46\x71\x01\x4a\x19\x3f\x40\xc1\x5f\xc2\x44",
191 .prk_size = 32,
192 .okm = "\xb1\x1e\x39\x8d\xc8\x03\x27\xa1\xc8\xe7\xf7\x8c\x59\x6a\x49\x34"
193 "\x4f\x01\x2e\xda\x2d\x4e\xfa\xd8\xa0\x50\xcc\x4c\x19\xaf\xa9\x7c"
194 "\x59\x04\x5a\x99\xca\xc7\x82\x72\x71\xcb\x41\xc6\x5e\x59\x0e\x09"
195 "\xda\x32\x75\x60\x0c\x2f\x09\xb8\x36\x77\x93\xa9\xac\xa3\xdb\x71"
196 "\xcc\x30\xc5\x81\x79\xec\x3e\x87\xc1\x4c\x01\xd5\xc1\xf3\x43\x4f"
197 "\x1d\x87",
198 .okm_size = 82,
199 }, {
200 .test = "hkdf test with zero salt and info",
201 .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b"
202 "\x0b\x0b\x0b\x0b\x0b\x0b",
203 .ikm_size = 22,
204 .salt = NULL,
205 .salt_size = 0,
206 .info = NULL,
207 .info_size = 0,
208 .prk = "\x19\xef\x24\xa3\x2c\x71\x7b\x16\x7f\x33\xa9\x1d\x6f\x64\x8b\xdf"
209 "\x96\x59\x67\x76\xaf\xdb\x63\x77\xac\x43\x4c\x1c\x29\x3c\xcb\x04",
210 .prk_size = 32,
211 .okm = "\x8d\xa4\xe7\x75\xa5\x63\xc1\x8f\x71\x5f\x80\x2a\x06\x3c\x5a\x31"
212 "\xb8\xa1\x1f\x5c\x5e\xe1\x87\x9e\xc3\x45\x4e\x5f\x3c\x73\x8d\x2d"
213 "\x9d\x20\x13\x95\xfa\xa4\xb6\x1a\x96\xc8",
214 .okm_size = 42,
215 }, {
216 .test = "hkdf test with short input",
217 .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b",
218 .ikm_size = 11,
219 .salt = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c",
220 .salt_size = 13,
221 .info = "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9",
222 .info_size = 10,
223 .prk = "\x82\x65\xf6\x9d\x7f\xf7\xe5\x01\x37\x93\x01\x5c\xa0\xef\x92\x0c"
224 "\xb1\x68\x21\x99\xc8\xbc\x3a\x00\xda\x0c\xab\x47\xb7\xb0\x0f\xdf",
225 .prk_size = 32,
226 .okm = "\x58\xdc\xe1\x0d\x58\x01\xcd\xfd\xa8\x31\x72\x6b\xfe\xbc\xb7\x43"
227 "\xd1\x4a\x7e\xe8\x3a\xa0\x57\xa9\x3d\x59\xb0\xa1\x31\x7f\xf0\x9d"
228 "\x10\x5c\xce\xcf\x53\x56\x92\xb1\x4d\xd5",
229 .okm_size = 42,
230 }, {
231 .test = "unsalted hkdf test with zero info",
232 .ikm = "\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c"
233 "\x0c\x0c\x0c\x0c\x0c\x0c",
234 .ikm_size = 22,
235 .salt = "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
236 "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
237 .salt_size = 32,
238 .info = NULL,
239 .info_size = 0,
240 .prk = "\xaa\x84\x1e\x1f\x35\x74\xf3\x2d\x13\xfb\xa8\x00\x5f\xcd\x9b\x8d"
241 "\x77\x67\x82\xa5\xdf\xa1\x92\x38\x92\xfd\x8b\x63\x5d\x3a\x89\xdf",
242 .prk_size = 32,
243 .okm = "\x59\x68\x99\x17\x9a\xb1\xbc\x00\xa7\xc0\x37\x86\xff\x43\xee\x53"
244 "\x50\x04\xbe\x2b\xb9\xbe\x68\xbc\x14\x06\x63\x6f\x54\xbd\x33\x8a"
245 "\x66\xa2\x37\xba\x2a\xcb\xce\xe3\xc9\xa7",
246 .okm_size = 42,
247 }
248};
249
250static const struct hkdf_testvec hkdf_sha384_tv[] = {
251 {
252 .test = "basic hkdf test",
253 .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b"
254 "\x0b\x0b\x0b\x0b\x0b\x0b",
255 .ikm_size = 22,
256 .salt = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c",
257 .salt_size = 13,
258 .info = "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9",
259 .info_size = 10,
260 .prk = "\x70\x4b\x39\x99\x07\x79\xce\x1d\xc5\x48\x05\x2c\x7d\xc3\x9f\x30"
261 "\x35\x70\xdd\x13\xfb\x39\xf7\xac\xc5\x64\x68\x0b\xef\x80\xe8\xde"
262 "\xc7\x0e\xe9\xa7\xe1\xf3\xe2\x93\xef\x68\xec\xeb\x07\x2a\x5a\xde",
263 .prk_size = 48,
264 .okm = "\x9b\x50\x97\xa8\x60\x38\xb8\x05\x30\x90\x76\xa4\x4b\x3a\x9f\x38"
265 "\x06\x3e\x25\xb5\x16\xdc\xbf\x36\x9f\x39\x4c\xfa\xb4\x36\x85\xf7"
266 "\x48\xb6\x45\x77\x63\xe4\xf0\x20\x4f\xc5",
267 .okm_size = 42,
268 }, {
269 .test = "hkdf test with long input",
270 .ikm = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
271 "\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"
272 "\x20\x21\x22\x23\x24\x25\x26\x27\x28\x29\x2a\x2b\x2c\x2d\x2e\x2f"
273 "\x30\x31\x32\x33\x34\x35\x36\x37\x38\x39\x3a\x3b\x3c\x3d\x3e\x3f"
274 "\x40\x41\x42\x43\x44\x45\x46\x47\x48\x49\x4a\x4b\x4c\x4d\x4e\x4f",
275 .ikm_size = 80,
276 .salt = "\x60\x61\x62\x63\x64\x65\x66\x67\x68\x69\x6a\x6b\x6c\x6d\x6e\x6f"
277 "\x70\x71\x72\x73\x74\x75\x76\x77\x78\x79\x7a\x7b\x7c\x7d\x7e\x7f"
278 "\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f"
279 "\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f"
280 "\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf",
281 .salt_size = 80,
282 .info = "\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf"
283 "\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf"
284 "\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf"
285 "\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef"
286 "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff",
287 .info_size = 80,
288 .prk = "\xb3\x19\xf6\x83\x1d\xff\x93\x14\xef\xb6\x43\xba\xa2\x92\x63\xb3"
289 "\x0e\x4a\x8d\x77\x9f\xe3\x1e\x9c\x90\x1e\xfd\x7d\xe7\x37\xc8\x5b"
290 "\x62\xe6\x76\xd4\xdc\x87\xb0\x89\x5c\x6a\x7d\xc9\x7b\x52\xce\xbb",
291 .prk_size = 48,
292 .okm = "\x48\x4c\xa0\x52\xb8\xcc\x72\x4f\xd1\xc4\xec\x64\xd5\x7b\x4e\x81"
293 "\x8c\x7e\x25\xa8\xe0\xf4\x56\x9e\xd7\x2a\x6a\x05\xfe\x06\x49\xee"
294 "\xbf\x69\xf8\xd5\xc8\x32\x85\x6b\xf4\xe4\xfb\xc1\x79\x67\xd5\x49"
295 "\x75\x32\x4a\x94\x98\x7f\x7f\x41\x83\x58\x17\xd8\x99\x4f\xdb\xd6"
296 "\xf4\xc0\x9c\x55\x00\xdc\xa2\x4a\x56\x22\x2f\xea\x53\xd8\x96\x7a"
297 "\x8b\x2e",
298 .okm_size = 82,
299 }, {
300 .test = "hkdf test with zero salt and info",
301 .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b"
302 "\x0b\x0b\x0b\x0b\x0b\x0b",
303 .ikm_size = 22,
304 .salt = NULL,
305 .salt_size = 0,
306 .info = NULL,
307 .info_size = 0,
308 .prk = "\x10\xe4\x0c\xf0\x72\xa4\xc5\x62\x6e\x43\xdd\x22\xc1\xcf\x72\x7d"
309 "\x4b\xb1\x40\x97\x5c\x9a\xd0\xcb\xc8\xe4\x5b\x40\x06\x8f\x8f\x0b"
310 "\xa5\x7c\xdb\x59\x8a\xf9\xdf\xa6\x96\x3a\x96\x89\x9a\xf0\x47\xe5",
311 .prk_size = 48,
312 .okm = "\xc8\xc9\x6e\x71\x0f\x89\xb0\xd7\x99\x0b\xca\x68\xbc\xde\xc8\xcf"
313 "\x85\x40\x62\xe5\x4c\x73\xa7\xab\xc7\x43\xfa\xde\x9b\x24\x2d\xaa"
314 "\xcc\x1c\xea\x56\x70\x41\x5b\x52\x84\x9c",
315 .okm_size = 42,
316 }, {
317 .test = "hkdf test with short input",
318 .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b",
319 .ikm_size = 11,
320 .salt = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c",
321 .salt_size = 13,
322 .info = "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9",
323 .info_size = 10,
324 .prk = "\x6d\x31\x69\x98\x28\x79\x80\x88\xb3\x59\xda\xd5\x0b\x8f\x01\xb0"
325 "\x15\xf1\x7a\xa3\xbd\x4e\x27\xa6\xe9\xf8\x73\xb7\x15\x85\xca\x6a"
326 "\x00\xd1\xf0\x82\x12\x8a\xdb\x3c\xf0\x53\x0b\x57\xc0\xf9\xac\x72",
327 .prk_size = 48,
328 .okm = "\xfb\x7e\x67\x43\xeb\x42\xcd\xe9\x6f\x1b\x70\x77\x89\x52\xab\x75"
329 "\x48\xca\xfe\x53\x24\x9f\x7f\xfe\x14\x97\xa1\x63\x5b\x20\x1f\xf1"
330 "\x85\xb9\x3e\x95\x19\x92\xd8\x58\xf1\x1a",
331 .okm_size = 42,
332 }, {
333 .test = "unsalted hkdf test with zero info",
334 .ikm = "\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c"
335 "\x0c\x0c\x0c\x0c\x0c\x0c",
336 .ikm_size = 22,
337 .salt = "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
338 "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
339 "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
340 .salt_size = 48,
341 .info = NULL,
342 .info_size = 0,
343 .prk = "\x9d\x2d\xa5\x06\x6f\x05\xd1\x6c\x59\xfe\xdf\x6c\x5f\x32\xc7\x5e"
344 "\xda\x9a\x47\xa7\x9c\x93\x6a\xa4\x4c\xb7\x63\xa8\xe2\x2f\xfb\xfc"
345 "\xd8\xfe\x55\x43\x58\x53\x47\x21\x90\x39\xd1\x68\x28\x36\x33\xf5",
346 .prk_size = 48,
347 .okm = "\x6a\xd7\xc7\x26\xc8\x40\x09\x54\x6a\x76\xe0\x54\x5d\xf2\x66\x78"
348 "\x7e\x2b\x2c\xd6\xca\x43\x73\xa1\xf3\x14\x50\xa7\xbd\xf9\x48\x2b"
349 "\xfa\xb8\x11\xf5\x54\x20\x0e\xad\x8f\x53",
350 .okm_size = 42,
351 }
352};
353
354static const struct hkdf_testvec hkdf_sha512_tv[] = {
355 {
356 .test = "basic hkdf test",
357 .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b"
358 "\x0b\x0b\x0b\x0b\x0b\x0b",
359 .ikm_size = 22,
360 .salt = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c",
361 .salt_size = 13,
362 .info = "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9",
363 .info_size = 10,
364 .prk = "\x66\x57\x99\x82\x37\x37\xde\xd0\x4a\x88\xe4\x7e\x54\xa5\x89\x0b"
365 "\xb2\xc3\xd2\x47\xc7\xa4\x25\x4a\x8e\x61\x35\x07\x23\x59\x0a\x26"
366 "\xc3\x62\x38\x12\x7d\x86\x61\xb8\x8c\xf8\x0e\xf8\x02\xd5\x7e\x2f"
367 "\x7c\xeb\xcf\x1e\x00\xe0\x83\x84\x8b\xe1\x99\x29\xc6\x1b\x42\x37",
368 .prk_size = 64,
369 .okm = "\x83\x23\x90\x08\x6c\xda\x71\xfb\x47\x62\x5b\xb5\xce\xb1\x68\xe4"
370 "\xc8\xe2\x6a\x1a\x16\xed\x34\xd9\xfc\x7f\xe9\x2c\x14\x81\x57\x93"
371 "\x38\xda\x36\x2c\xb8\xd9\xf9\x25\xd7\xcb",
372 .okm_size = 42,
373 }, {
374 .test = "hkdf test with long input",
375 .ikm = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
376 "\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"
377 "\x20\x21\x22\x23\x24\x25\x26\x27\x28\x29\x2a\x2b\x2c\x2d\x2e\x2f"
378 "\x30\x31\x32\x33\x34\x35\x36\x37\x38\x39\x3a\x3b\x3c\x3d\x3e\x3f"
379 "\x40\x41\x42\x43\x44\x45\x46\x47\x48\x49\x4a\x4b\x4c\x4d\x4e\x4f",
380 .ikm_size = 80,
381 .salt = "\x60\x61\x62\x63\x64\x65\x66\x67\x68\x69\x6a\x6b\x6c\x6d\x6e\x6f"
382 "\x70\x71\x72\x73\x74\x75\x76\x77\x78\x79\x7a\x7b\x7c\x7d\x7e\x7f"
383 "\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f"
384 "\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f"
385 "\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf",
386 .salt_size = 80,
387 .info = "\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf"
388 "\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf"
389 "\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf"
390 "\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef"
391 "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff",
392 .info_size = 80,
393 .prk = "\x35\x67\x25\x42\x90\x7d\x4e\x14\x2c\x00\xe8\x44\x99\xe7\x4e\x1d"
394 "\xe0\x8b\xe8\x65\x35\xf9\x24\xe0\x22\x80\x4a\xd7\x75\xdd\xe2\x7e"
395 "\xc8\x6c\xd1\xe5\xb7\xd1\x78\xc7\x44\x89\xbd\xbe\xb3\x07\x12\xbe"
396 "\xb8\x2d\x4f\x97\x41\x6c\x5a\x94\xea\x81\xeb\xdf\x3e\x62\x9e\x4a",
397 .prk_size = 64,
398 .okm = "\xce\x6c\x97\x19\x28\x05\xb3\x46\xe6\x16\x1e\x82\x1e\xd1\x65\x67"
399 "\x3b\x84\xf4\x00\xa2\xb5\x14\xb2\xfe\x23\xd8\x4c\xd1\x89\xdd\xf1"
400 "\xb6\x95\xb4\x8c\xbd\x1c\x83\x88\x44\x11\x37\xb3\xce\x28\xf1\x6a"
401 "\xa6\x4b\xa3\x3b\xa4\x66\xb2\x4d\xf6\xcf\xcb\x02\x1e\xcf\xf2\x35"
402 "\xf6\xa2\x05\x6c\xe3\xaf\x1d\xe4\x4d\x57\x20\x97\xa8\x50\x5d\x9e"
403 "\x7a\x93",
404 .okm_size = 82,
405 }, {
406 .test = "hkdf test with zero salt and info",
407 .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b"
408 "\x0b\x0b\x0b\x0b\x0b\x0b",
409 .ikm_size = 22,
410 .salt = NULL,
411 .salt_size = 0,
412 .info = NULL,
413 .info_size = 0,
414 .prk = "\xfd\x20\x0c\x49\x87\xac\x49\x13\x13\xbd\x4a\x2a\x13\x28\x71\x21"
415 "\x24\x72\x39\xe1\x1c\x9e\xf8\x28\x02\x04\x4b\x66\xef\x35\x7e\x5b"
416 "\x19\x44\x98\xd0\x68\x26\x11\x38\x23\x48\x57\x2a\x7b\x16\x11\xde"
417 "\x54\x76\x40\x94\x28\x63\x20\x57\x8a\x86\x3f\x36\x56\x2b\x0d\xf6",
418 .prk_size = 64,
419 .okm = "\xf5\xfa\x02\xb1\x82\x98\xa7\x2a\x8c\x23\x89\x8a\x87\x03\x47\x2c"
420 "\x6e\xb1\x79\xdc\x20\x4c\x03\x42\x5c\x97\x0e\x3b\x16\x4b\xf9\x0f"
421 "\xff\x22\xd0\x48\x36\xd0\xe2\x34\x3b\xac",
422 .okm_size = 42,
423 }, {
424 .test = "hkdf test with short input",
425 .ikm = "\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b\x0b",
426 .ikm_size = 11,
427 .salt = "\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c",
428 .salt_size = 13,
429 .info = "\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9",
430 .info_size = 10,
431 .prk = "\x67\x40\x9c\x9c\xac\x28\xb5\x2e\xe9\xfa\xd9\x1c\x2f\xda\x99\x9f"
432 "\x7c\xa2\x2e\x34\x34\xf0\xae\x77\x28\x63\x83\x65\x68\xad\x6a\x7f"
433 "\x10\xcf\x11\x3b\xfd\xdd\x56\x01\x29\xa5\x94\xa8\xf5\x23\x85\xc2"
434 "\xd6\x61\xd7\x85\xd2\x9c\xe9\x3a\x11\x40\x0c\x92\x06\x83\x18\x1d",
435 .prk_size = 64,
436 .okm = "\x74\x13\xe8\x99\x7e\x02\x06\x10\xfb\xf6\x82\x3f\x2c\xe1\x4b\xff"
437 "\x01\x87\x5d\xb1\xca\x55\xf6\x8c\xfc\xf3\x95\x4d\xc8\xaf\xf5\x35"
438 "\x59\xbd\x5e\x30\x28\xb0\x80\xf7\xc0\x68",
439 .okm_size = 42,
440 }, {
441 .test = "unsalted hkdf test with zero info",
442 .ikm = "\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c\x0c"
443 "\x0c\x0c\x0c\x0c\x0c\x0c",
444 .ikm_size = 22,
445 .salt = "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
446 "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
447 "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
448 "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
449 .salt_size = 64,
450 .info = NULL,
451 .info_size = 0,
452 .prk = "\x53\x46\xb3\x76\xbf\x3a\xa9\xf8\x4f\x8f\x6e\xd5\xb1\xc4\xf4\x89"
453 "\x17\x2e\x24\x4d\xac\x30\x3d\x12\xf6\x8e\xcc\x76\x6e\xa6\x00\xaa"
454 "\x88\x49\x5e\x7f\xb6\x05\x80\x31\x22\xfa\x13\x69\x24\xa8\x40\xb1"
455 "\xf0\x71\x9d\x2d\x5f\x68\xe2\x9b\x24\x22\x99\xd7\x58\xed\x68\x0c",
456 .prk_size = 64,
457 .okm = "\x14\x07\xd4\x60\x13\xd9\x8b\xc6\xde\xce\xfc\xfe\xe5\x5f\x0f\x90"
458 "\xb0\xc7\xf6\x3d\x68\xeb\x1a\x80\xea\xf0\x7e\x95\x3c\xfc\x0a\x3a"
459 "\x52\x40\xa1\x55\xd6\xe4\xda\xa9\x65\xbb",
460 .okm_size = 42,
461 }
462};
463
464static int hkdf_test(const char *shash, const struct hkdf_testvec *tv)
465{ struct crypto_shash *tfm = NULL;
466 u8 *prk = NULL, *okm = NULL;
467 unsigned int prk_size;
468 const char *driver;
469 int err;
470
471 tfm = crypto_alloc_shash(alg_name: shash, type: 0, mask: 0);
472 if (IS_ERR(ptr: tfm)) {
473 pr_err("%s(%s): failed to allocate transform: %ld\n",
474 tv->test, shash, PTR_ERR(tfm));
475 return PTR_ERR(ptr: tfm);
476 }
477 driver = crypto_shash_driver_name(tfm);
478
479 prk_size = crypto_shash_digestsize(tfm);
480 prk = kzalloc(prk_size, GFP_KERNEL);
481 if (!prk) {
482 err = -ENOMEM;
483 goto out_free;
484 }
485
486 if (tv->prk_size != prk_size) {
487 pr_err("%s(%s): prk size mismatch (vec %u, digest %u\n",
488 tv->test, driver, tv->prk_size, prk_size);
489 err = -EINVAL;
490 goto out_free;
491 }
492
493 err = hkdf_extract(tfm, tv->ikm, tv->ikm_size,
494 tv->salt, tv->salt_size, prk);
495 if (err) {
496 pr_err("%s(%s): hkdf_extract failed with %d\n",
497 tv->test, driver, err);
498 goto out_free;
499 }
500
501 if (memcmp(p: prk, q: tv->prk, size: tv->prk_size)) {
502 pr_err("%s(%s): hkdf_extract prk mismatch\n",
503 tv->test, driver);
504 print_hex_dump(KERN_ERR, prefix_str: "prk: ", prefix_type: DUMP_PREFIX_NONE,
505 rowsize: 16, groupsize: 1, buf: prk, len: tv->prk_size, ascii: false);
506 err = -EINVAL;
507 goto out_free;
508 }
509
510 okm = kzalloc(tv->okm_size, GFP_KERNEL);
511 if (!okm) {
512 err = -ENOMEM;
513 goto out_free;
514 }
515
516 err = crypto_shash_setkey(tfm, key: tv->prk, keylen: tv->prk_size);
517 if (err) {
518 pr_err("%s(%s): failed to set prk, error %d\n",
519 tv->test, driver, err);
520 goto out_free;
521 }
522
523 err = hkdf_expand(tfm, tv->info, tv->info_size,
524 okm, tv->okm_size);
525 if (err) {
526 pr_err("%s(%s): hkdf_expand() failed with %d\n",
527 tv->test, driver, err);
528 } else if (memcmp(p: okm, q: tv->okm, size: tv->okm_size)) {
529 pr_err("%s(%s): hkdf_expand() okm mismatch\n",
530 tv->test, driver);
531 print_hex_dump(KERN_ERR, prefix_str: "okm: ", prefix_type: DUMP_PREFIX_NONE,
532 rowsize: 16, groupsize: 1, buf: okm, len: tv->okm_size, ascii: false);
533 err = -EINVAL;
534 }
535out_free:
536 kfree(objp: okm);
537 kfree(objp: prk);
538 crypto_free_shash(tfm);
539 return err;
540}
541
542static int __init crypto_hkdf_module_init(void)
543{
544 int ret = 0, i;
545
546 if (!IS_ENABLED(CONFIG_CRYPTO_SELFTESTS))
547 return 0;
548
549 for (i = 0; i < ARRAY_SIZE(hkdf_sha256_tv); i++) {
550 ret = hkdf_test(shash: "hmac(sha256)", tv: &hkdf_sha256_tv[i]);
551 if (ret)
552 return ret;
553 }
554 for (i = 0; i < ARRAY_SIZE(hkdf_sha384_tv); i++) {
555 ret = hkdf_test(shash: "hmac(sha384)", tv: &hkdf_sha384_tv[i]);
556 if (ret)
557 return ret;
558 }
559 for (i = 0; i < ARRAY_SIZE(hkdf_sha512_tv); i++) {
560 ret = hkdf_test(shash: "hmac(sha512)", tv: &hkdf_sha512_tv[i]);
561 if (ret)
562 return ret;
563 }
564 return 0;
565}
566
567static void __exit crypto_hkdf_module_exit(void) {}
568
569late_initcall(crypto_hkdf_module_init);
570module_exit(crypto_hkdf_module_exit);
571
572MODULE_LICENSE("GPL");
573MODULE_DESCRIPTION("HMAC-based Key Derivation Function (HKDF)");
574

source code of linux/crypto/hkdf.c