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path: root/crypto/hmac.c (plain)
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1/*
2 * Cryptographic API.
3 *
4 * HMAC: Keyed-Hashing for Message Authentication (RFC2104).
5 *
6 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
7 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
8 *
9 * The HMAC implementation is derived from USAGI.
10 * Copyright (c) 2002 Kazunori Miyazawa <miyazawa@linux-ipv6.org> / USAGI
11 *
12 * This program is free software; you can redistribute it and/or modify it
13 * under the terms of the GNU General Public License as published by the Free
14 * Software Foundation; either version 2 of the License, or (at your option)
15 * any later version.
16 *
17 */
18
19#include <crypto/internal/hash.h>
20#include <crypto/scatterwalk.h>
21#include <linux/err.h>
22#include <linux/init.h>
23#include <linux/kernel.h>
24#include <linux/module.h>
25#include <linux/scatterlist.h>
26#include <linux/string.h>
27
28struct hmac_ctx {
29 struct crypto_shash *hash;
30};
31
32static inline void *align_ptr(void *p, unsigned int align)
33{
34 return (void *)ALIGN((unsigned long)p, align);
35}
36
37static inline struct hmac_ctx *hmac_ctx(struct crypto_shash *tfm)
38{
39 return align_ptr(crypto_shash_ctx_aligned(tfm) +
40 crypto_shash_statesize(tfm) * 2,
41 crypto_tfm_ctx_alignment());
42}
43
44static int hmac_setkey(struct crypto_shash *parent,
45 const u8 *inkey, unsigned int keylen)
46{
47 int bs = crypto_shash_blocksize(parent);
48 int ds = crypto_shash_digestsize(parent);
49 int ss = crypto_shash_statesize(parent);
50 char *ipad = crypto_shash_ctx_aligned(parent);
51 char *opad = ipad + ss;
52 struct hmac_ctx *ctx = align_ptr(opad + ss,
53 crypto_tfm_ctx_alignment());
54 struct crypto_shash *hash = ctx->hash;
55 SHASH_DESC_ON_STACK(shash, hash);
56 unsigned int i;
57
58 shash->tfm = hash;
59 shash->flags = crypto_shash_get_flags(parent)
60 & CRYPTO_TFM_REQ_MAY_SLEEP;
61
62 if (keylen > bs) {
63 int err;
64
65 err = crypto_shash_digest(shash, inkey, keylen, ipad);
66 if (err)
67 return err;
68
69 keylen = ds;
70 } else
71 memcpy(ipad, inkey, keylen);
72
73 memset(ipad + keylen, 0, bs - keylen);
74 memcpy(opad, ipad, bs);
75
76 for (i = 0; i < bs; i++) {
77 ipad[i] ^= 0x36;
78 opad[i] ^= 0x5c;
79 }
80
81 return crypto_shash_init(shash) ?:
82 crypto_shash_update(shash, ipad, bs) ?:
83 crypto_shash_export(shash, ipad) ?:
84 crypto_shash_init(shash) ?:
85 crypto_shash_update(shash, opad, bs) ?:
86 crypto_shash_export(shash, opad);
87}
88
89static int hmac_export(struct shash_desc *pdesc, void *out)
90{
91 struct shash_desc *desc = shash_desc_ctx(pdesc);
92
93 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
94
95 return crypto_shash_export(desc, out);
96}
97
98static int hmac_import(struct shash_desc *pdesc, const void *in)
99{
100 struct shash_desc *desc = shash_desc_ctx(pdesc);
101 struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);
102
103 desc->tfm = ctx->hash;
104 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
105
106 return crypto_shash_import(desc, in);
107}
108
109static int hmac_init(struct shash_desc *pdesc)
110{
111 return hmac_import(pdesc, crypto_shash_ctx_aligned(pdesc->tfm));
112}
113
114static int hmac_update(struct shash_desc *pdesc,
115 const u8 *data, unsigned int nbytes)
116{
117 struct shash_desc *desc = shash_desc_ctx(pdesc);
118
119 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
120
121 return crypto_shash_update(desc, data, nbytes);
122}
123
124static int hmac_final(struct shash_desc *pdesc, u8 *out)
125{
126 struct crypto_shash *parent = pdesc->tfm;
127 int ds = crypto_shash_digestsize(parent);
128 int ss = crypto_shash_statesize(parent);
129 char *opad = crypto_shash_ctx_aligned(parent) + ss;
130 struct shash_desc *desc = shash_desc_ctx(pdesc);
131
132 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
133
134 return crypto_shash_final(desc, out) ?:
135 crypto_shash_import(desc, opad) ?:
136 crypto_shash_finup(desc, out, ds, out);
137}
138
139static int hmac_finup(struct shash_desc *pdesc, const u8 *data,
140 unsigned int nbytes, u8 *out)
141{
142
143 struct crypto_shash *parent = pdesc->tfm;
144 int ds = crypto_shash_digestsize(parent);
145 int ss = crypto_shash_statesize(parent);
146 char *opad = crypto_shash_ctx_aligned(parent) + ss;
147 struct shash_desc *desc = shash_desc_ctx(pdesc);
148
149 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
150
151 return crypto_shash_finup(desc, data, nbytes, out) ?:
152 crypto_shash_import(desc, opad) ?:
153 crypto_shash_finup(desc, out, ds, out);
154}
155
156static int hmac_init_tfm(struct crypto_tfm *tfm)
157{
158 struct crypto_shash *parent = __crypto_shash_cast(tfm);
159 struct crypto_shash *hash;
160 struct crypto_instance *inst = (void *)tfm->__crt_alg;
161 struct crypto_shash_spawn *spawn = crypto_instance_ctx(inst);
162 struct hmac_ctx *ctx = hmac_ctx(parent);
163
164 hash = crypto_spawn_shash(spawn);
165 if (IS_ERR(hash))
166 return PTR_ERR(hash);
167
168 parent->descsize = sizeof(struct shash_desc) +
169 crypto_shash_descsize(hash);
170
171 ctx->hash = hash;
172 return 0;
173}
174
175static void hmac_exit_tfm(struct crypto_tfm *tfm)
176{
177 struct hmac_ctx *ctx = hmac_ctx(__crypto_shash_cast(tfm));
178 crypto_free_shash(ctx->hash);
179}
180
181static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
182{
183 struct shash_instance *inst;
184 struct crypto_alg *alg;
185 struct shash_alg *salg;
186 int err;
187 int ds;
188 int ss;
189
190 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
191 if (err)
192 return err;
193
194 salg = shash_attr_alg(tb[1], 0, 0);
195 if (IS_ERR(salg))
196 return PTR_ERR(salg);
197 alg = &salg->base;
198
199 /* The underlying hash algorithm must be unkeyed */
200 err = -EINVAL;
201 if (crypto_shash_alg_has_setkey(salg))
202 goto out_put_alg;
203
204 ds = salg->digestsize;
205 ss = salg->statesize;
206 if (ds > alg->cra_blocksize ||
207 ss < alg->cra_blocksize)
208 goto out_put_alg;
209
210 inst = shash_alloc_instance("hmac", alg);
211 err = PTR_ERR(inst);
212 if (IS_ERR(inst))
213 goto out_put_alg;
214
215 err = crypto_init_shash_spawn(shash_instance_ctx(inst), salg,
216 shash_crypto_instance(inst));
217 if (err)
218 goto out_free_inst;
219
220 inst->alg.base.cra_priority = alg->cra_priority;
221 inst->alg.base.cra_blocksize = alg->cra_blocksize;
222 inst->alg.base.cra_alignmask = alg->cra_alignmask;
223
224 ss = ALIGN(ss, alg->cra_alignmask + 1);
225 inst->alg.digestsize = ds;
226 inst->alg.statesize = ss;
227
228 inst->alg.base.cra_ctxsize = sizeof(struct hmac_ctx) +
229 ALIGN(ss * 2, crypto_tfm_ctx_alignment());
230
231 inst->alg.base.cra_init = hmac_init_tfm;
232 inst->alg.base.cra_exit = hmac_exit_tfm;
233
234 inst->alg.init = hmac_init;
235 inst->alg.update = hmac_update;
236 inst->alg.final = hmac_final;
237 inst->alg.finup = hmac_finup;
238 inst->alg.export = hmac_export;
239 inst->alg.import = hmac_import;
240 inst->alg.setkey = hmac_setkey;
241
242 err = shash_register_instance(tmpl, inst);
243 if (err) {
244out_free_inst:
245 shash_free_instance(shash_crypto_instance(inst));
246 }
247
248out_put_alg:
249 crypto_mod_put(alg);
250 return err;
251}
252
253static struct crypto_template hmac_tmpl = {
254 .name = "hmac",
255 .create = hmac_create,
256 .free = shash_free_instance,
257 .module = THIS_MODULE,
258};
259
260static int __init hmac_module_init(void)
261{
262 return crypto_register_template(&hmac_tmpl);
263}
264
265static void __exit hmac_module_exit(void)
266{
267 crypto_unregister_template(&hmac_tmpl);
268}
269
270module_init(hmac_module_init);
271module_exit(hmac_module_exit);
272
273MODULE_LICENSE("GPL");
274MODULE_DESCRIPTION("HMAC hash algorithm");
275MODULE_ALIAS_CRYPTO("hmac");
276
generated by cgit at 2024-05-19 01:00:48 (GMT)