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1da177e4
LT
1/*
2 * Cryptographic API.
3 *
4 * HMAC: Keyed-Hashing for Message Authentication (RFC2104).
5 *
6 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
0796ae06 7 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
1da177e4
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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
0796ae06 14 * Software Foundation; either version 2 of the License, or (at your option)
1da177e4
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15 * any later version.
16 *
17 */
0796ae06 18
5f7082ed 19#include <crypto/internal/hash.h>
b2ab4a57 20#include <crypto/scatterwalk.h>
0796ae06
HX
21#include <linux/err.h>
22#include <linux/init.h>
23#include <linux/kernel.h>
24#include <linux/module.h>
378f058c 25#include <linux/scatterlist.h>
0796ae06
HX
26#include <linux/string.h>
27
28struct hmac_ctx {
0b767b4d 29 struct crypto_shash *hash;
0796ae06 30};
1da177e4 31
0796ae06
HX
32static inline void *align_ptr(void *p, unsigned int align)
33{
34 return (void *)ALIGN((unsigned long)p, align);
35}
36
8bd1209c 37static inline struct hmac_ctx *hmac_ctx(struct crypto_shash *tfm)
0796ae06 38{
8bd1209c 39 return align_ptr(crypto_shash_ctx_aligned(tfm) +
0b767b4d 40 crypto_shash_statesize(tfm) * 2,
8bd1209c 41 crypto_tfm_ctx_alignment());
0796ae06
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42}
43
8bd1209c 44static int hmac_setkey(struct crypto_shash *parent,
0796ae06
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45 const u8 *inkey, unsigned int keylen)
46{
8bd1209c
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47 int bs = crypto_shash_blocksize(parent);
48 int ds = crypto_shash_digestsize(parent);
0b767b4d 49 int ss = crypto_shash_statesize(parent);
8bd1209c 50 char *ipad = crypto_shash_ctx_aligned(parent);
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51 char *opad = ipad + ss;
52 struct hmac_ctx *ctx = align_ptr(opad + ss,
8bd1209c 53 crypto_tfm_ctx_alignment());
0b767b4d 54 struct crypto_shash *hash = ctx->hash;
ffb32e97 55 SHASH_DESC_ON_STACK(shash, hash);
0796ae06
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56 unsigned int i;
57
ffb32e97
JSM
58 shash->tfm = hash;
59 shash->flags = crypto_shash_get_flags(parent)
60 & CRYPTO_TFM_REQ_MAY_SLEEP;
0b767b4d 61
0796ae06 62 if (keylen > bs) {
0796ae06
HX
63 int err;
64
ffb32e97 65 err = crypto_shash_digest(shash, inkey, keylen, ipad);
0796ae06
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66 if (err)
67 return err;
68
0796ae06 69 keylen = ds;
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70 } else
71 memcpy(ipad, inkey, keylen);
0796ae06 72
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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
ffb32e97
JSM
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);
0796ae06
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87}
88
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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)
0796ae06 99{
8bd1209c 100 struct shash_desc *desc = shash_desc_ctx(pdesc);
0b767b4d 101 struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);
8bd1209c 102
0b767b4d 103 desc->tfm = ctx->hash;
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HX
104 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
105
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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));
0796ae06
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112}
113
8bd1209c
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114static int hmac_update(struct shash_desc *pdesc,
115 const u8 *data, unsigned int nbytes)
0796ae06 116{
8bd1209c 117 struct shash_desc *desc = shash_desc_ctx(pdesc);
0796ae06 118
8bd1209c 119 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
0796ae06 120
8bd1209c 121 return crypto_shash_update(desc, data, nbytes);
0796ae06
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122}
123
8bd1209c 124static int hmac_final(struct shash_desc *pdesc, u8 *out)
0796ae06 125{
8bd1209c 126 struct crypto_shash *parent = pdesc->tfm;
8bd1209c 127 int ds = crypto_shash_digestsize(parent);
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128 int ss = crypto_shash_statesize(parent);
129 char *opad = crypto_shash_ctx_aligned(parent) + ss;
8bd1209c 130 struct shash_desc *desc = shash_desc_ctx(pdesc);
0796ae06 131
8bd1209c 132 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
73af07de 133
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134 return crypto_shash_final(desc, out) ?:
135 crypto_shash_import(desc, opad) ?:
136 crypto_shash_finup(desc, out, ds, out);
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137}
138
8bd1209c
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139static int hmac_finup(struct shash_desc *pdesc, const u8 *data,
140 unsigned int nbytes, u8 *out)
0796ae06 141{
0796ae06 142
8bd1209c 143 struct crypto_shash *parent = pdesc->tfm;
8bd1209c 144 int ds = crypto_shash_digestsize(parent);
0b767b4d
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145 int ss = crypto_shash_statesize(parent);
146 char *opad = crypto_shash_ctx_aligned(parent) + ss;
8bd1209c 147 struct shash_desc *desc = shash_desc_ctx(pdesc);
78c2f0b8 148
8bd1209c 149 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
0796ae06 150
0b767b4d
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151 return crypto_shash_finup(desc, data, nbytes, out) ?:
152 crypto_shash_import(desc, opad) ?:
153 crypto_shash_finup(desc, out, ds, out);
0796ae06
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154}
155
156static int hmac_init_tfm(struct crypto_tfm *tfm)
157{
8bd1209c
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158 struct crypto_shash *parent = __crypto_shash_cast(tfm);
159 struct crypto_shash *hash;
0796ae06 160 struct crypto_instance *inst = (void *)tfm->__crt_alg;
8bd1209c
HX
161 struct crypto_shash_spawn *spawn = crypto_instance_ctx(inst);
162 struct hmac_ctx *ctx = hmac_ctx(parent);
0796ae06 163
8bd1209c 164 hash = crypto_spawn_shash(spawn);
2e306ee0
HX
165 if (IS_ERR(hash))
166 return PTR_ERR(hash);
0796ae06 167
8bd1209c
HX
168 parent->descsize = sizeof(struct shash_desc) +
169 crypto_shash_descsize(hash);
170
0b767b4d 171 ctx->hash = hash;
0796ae06
HX
172 return 0;
173}
174
175static void hmac_exit_tfm(struct crypto_tfm *tfm)
176{
8bd1209c 177 struct hmac_ctx *ctx = hmac_ctx(__crypto_shash_cast(tfm));
0b767b4d 178 crypto_free_shash(ctx->hash);
0796ae06
HX
179}
180
8bd1209c 181static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
0796ae06 182{
8bd1209c 183 struct shash_instance *inst;
0796ae06 184 struct crypto_alg *alg;
8bd1209c 185 struct shash_alg *salg;
ebc610e5 186 int err;
ca786dc7 187 int ds;
0b767b4d 188 int ss;
ebc610e5 189
8bd1209c 190 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
ebc610e5 191 if (err)
8bd1209c
HX
192 return err;
193
194 salg = shash_attr_alg(tb[1], 0, 0);
195 if (IS_ERR(salg))
196 return PTR_ERR(salg);
197
198 err = -EINVAL;
199 ds = salg->digestsize;
0b767b4d 200 ss = salg->statesize;
8bd1209c 201 alg = &salg->base;
0b767b4d
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202 if (ds > alg->cra_blocksize ||
203 ss < alg->cra_blocksize)
ca786dc7
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204 goto out_put_alg;
205
8bd1209c 206 inst = shash_alloc_instance("hmac", alg);
3b3fc322 207 err = PTR_ERR(inst);
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208 if (IS_ERR(inst))
209 goto out_put_alg;
210
8bd1209c
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211 err = crypto_init_shash_spawn(shash_instance_ctx(inst), salg,
212 shash_crypto_instance(inst));
213 if (err)
214 goto out_free_inst;
215
216 inst->alg.base.cra_priority = alg->cra_priority;
217 inst->alg.base.cra_blocksize = alg->cra_blocksize;
218 inst->alg.base.cra_alignmask = alg->cra_alignmask;
0796ae06 219
0b767b4d 220 ss = ALIGN(ss, alg->cra_alignmask + 1);
8bd1209c 221 inst->alg.digestsize = ds;
0b767b4d 222 inst->alg.statesize = ss;
0796ae06 223
8bd1209c 224 inst->alg.base.cra_ctxsize = sizeof(struct hmac_ctx) +
0b767b4d 225 ALIGN(ss * 2, crypto_tfm_ctx_alignment());
0796ae06 226
8bd1209c
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227 inst->alg.base.cra_init = hmac_init_tfm;
228 inst->alg.base.cra_exit = hmac_exit_tfm;
0796ae06 229
8bd1209c
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230 inst->alg.init = hmac_init;
231 inst->alg.update = hmac_update;
232 inst->alg.final = hmac_final;
233 inst->alg.finup = hmac_finup;
0b767b4d
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234 inst->alg.export = hmac_export;
235 inst->alg.import = hmac_import;
8bd1209c
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236 inst->alg.setkey = hmac_setkey;
237
238 err = shash_register_instance(tmpl, inst);
239 if (err) {
240out_free_inst:
241 shash_free_instance(shash_crypto_instance(inst));
242 }
0796ae06
HX
243
244out_put_alg:
245 crypto_mod_put(alg);
8bd1209c 246 return err;
0796ae06
HX
247}
248
249static struct crypto_template hmac_tmpl = {
250 .name = "hmac",
8bd1209c
HX
251 .create = hmac_create,
252 .free = shash_free_instance,
0796ae06
HX
253 .module = THIS_MODULE,
254};
255
256static int __init hmac_module_init(void)
257{
258 return crypto_register_template(&hmac_tmpl);
259}
260
261static void __exit hmac_module_exit(void)
262{
263 crypto_unregister_template(&hmac_tmpl);
264}
265
266module_init(hmac_module_init);
267module_exit(hmac_module_exit);
268
269MODULE_LICENSE("GPL");
270MODULE_DESCRIPTION("HMAC hash algorithm");
4943ba16 271MODULE_ALIAS_CRYPTO("hmac");