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CommitLineData
1da177e4
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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>
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>
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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
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26#include <linux/string.h>
27
28struct hmac_ctx {
0b767b4d 29 struct crypto_shash *hash;
0796ae06 30};
1da177e4 31
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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());
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42}
43
8bd1209c 44static int hmac_setkey(struct crypto_shash *parent,
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45 const u8 *inkey, unsigned int keylen)
46{
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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());
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54 struct crypto_shash *hash = ctx->hash;
55 struct {
56 struct shash_desc shash;
57 char ctx[crypto_shash_descsize(hash)];
58 } desc;
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59 unsigned int i;
60
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61 desc.shash.tfm = hash;
62 desc.shash.flags = crypto_shash_get_flags(parent) &
63 CRYPTO_TFM_REQ_MAY_SLEEP;
64
0796ae06 65 if (keylen > bs) {
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66 int err;
67
0b767b4d 68 err = crypto_shash_digest(&desc.shash, inkey, keylen, ipad);
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69 if (err)
70 return err;
71
0796ae06 72 keylen = ds;
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73 } else
74 memcpy(ipad, inkey, keylen);
0796ae06 75
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76 memset(ipad + keylen, 0, bs - keylen);
77 memcpy(opad, ipad, bs);
78
79 for (i = 0; i < bs; i++) {
80 ipad[i] ^= 0x36;
81 opad[i] ^= 0x5c;
82 }
83
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84 return crypto_shash_init(&desc.shash) ?:
85 crypto_shash_update(&desc.shash, ipad, bs) ?:
86 crypto_shash_export(&desc.shash, ipad) ?:
87 crypto_shash_init(&desc.shash) ?:
88 crypto_shash_update(&desc.shash, opad, bs) ?:
89 crypto_shash_export(&desc.shash, opad);
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90}
91
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92static int hmac_export(struct shash_desc *pdesc, void *out)
93{
94 struct shash_desc *desc = shash_desc_ctx(pdesc);
95
96 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
97
98 return crypto_shash_export(desc, out);
99}
100
101static int hmac_import(struct shash_desc *pdesc, const void *in)
0796ae06 102{
8bd1209c 103 struct shash_desc *desc = shash_desc_ctx(pdesc);
0b767b4d 104 struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);
8bd1209c 105
0b767b4d 106 desc->tfm = ctx->hash;
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107 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
108
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109 return crypto_shash_import(desc, in);
110}
111
112static int hmac_init(struct shash_desc *pdesc)
113{
114 return hmac_import(pdesc, crypto_shash_ctx_aligned(pdesc->tfm));
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115}
116
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117static int hmac_update(struct shash_desc *pdesc,
118 const u8 *data, unsigned int nbytes)
0796ae06 119{
8bd1209c 120 struct shash_desc *desc = shash_desc_ctx(pdesc);
0796ae06 121
8bd1209c 122 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
0796ae06 123
8bd1209c 124 return crypto_shash_update(desc, data, nbytes);
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125}
126
8bd1209c 127static int hmac_final(struct shash_desc *pdesc, u8 *out)
0796ae06 128{
8bd1209c 129 struct crypto_shash *parent = pdesc->tfm;
8bd1209c 130 int ds = crypto_shash_digestsize(parent);
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131 int ss = crypto_shash_statesize(parent);
132 char *opad = crypto_shash_ctx_aligned(parent) + ss;
8bd1209c 133 struct shash_desc *desc = shash_desc_ctx(pdesc);
0796ae06 134
8bd1209c 135 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
73af07de 136
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137 return crypto_shash_final(desc, out) ?:
138 crypto_shash_import(desc, opad) ?:
139 crypto_shash_finup(desc, out, ds, out);
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140}
141
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142static int hmac_finup(struct shash_desc *pdesc, const u8 *data,
143 unsigned int nbytes, u8 *out)
0796ae06 144{
0796ae06 145
8bd1209c 146 struct crypto_shash *parent = pdesc->tfm;
8bd1209c 147 int ds = crypto_shash_digestsize(parent);
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148 int ss = crypto_shash_statesize(parent);
149 char *opad = crypto_shash_ctx_aligned(parent) + ss;
8bd1209c 150 struct shash_desc *desc = shash_desc_ctx(pdesc);
78c2f0b8 151
8bd1209c 152 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
0796ae06 153
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154 return crypto_shash_finup(desc, data, nbytes, out) ?:
155 crypto_shash_import(desc, opad) ?:
156 crypto_shash_finup(desc, out, ds, out);
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157}
158
159static int hmac_init_tfm(struct crypto_tfm *tfm)
160{
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161 struct crypto_shash *parent = __crypto_shash_cast(tfm);
162 struct crypto_shash *hash;
0796ae06 163 struct crypto_instance *inst = (void *)tfm->__crt_alg;
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164 struct crypto_shash_spawn *spawn = crypto_instance_ctx(inst);
165 struct hmac_ctx *ctx = hmac_ctx(parent);
0796ae06 166
8bd1209c 167 hash = crypto_spawn_shash(spawn);
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168 if (IS_ERR(hash))
169 return PTR_ERR(hash);
0796ae06 170
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171 parent->descsize = sizeof(struct shash_desc) +
172 crypto_shash_descsize(hash);
173
0b767b4d 174 ctx->hash = hash;
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175 return 0;
176}
177
178static void hmac_exit_tfm(struct crypto_tfm *tfm)
179{
8bd1209c 180 struct hmac_ctx *ctx = hmac_ctx(__crypto_shash_cast(tfm));
0b767b4d 181 crypto_free_shash(ctx->hash);
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182}
183
8bd1209c 184static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
0796ae06 185{
8bd1209c 186 struct shash_instance *inst;
0796ae06 187 struct crypto_alg *alg;
8bd1209c 188 struct shash_alg *salg;
ebc610e5 189 int err;
ca786dc7 190 int ds;
0b767b4d 191 int ss;
ebc610e5 192
8bd1209c 193 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
ebc610e5 194 if (err)
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195 return err;
196
197 salg = shash_attr_alg(tb[1], 0, 0);
198 if (IS_ERR(salg))
199 return PTR_ERR(salg);
200
201 err = -EINVAL;
202 ds = salg->digestsize;
0b767b4d 203 ss = salg->statesize;
8bd1209c 204 alg = &salg->base;
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205 if (ds > alg->cra_blocksize ||
206 ss < alg->cra_blocksize)
ca786dc7
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207 goto out_put_alg;
208
8bd1209c 209 inst = shash_alloc_instance("hmac", alg);
3b3fc322 210 err = PTR_ERR(inst);
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211 if (IS_ERR(inst))
212 goto out_put_alg;
213
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214 err = crypto_init_shash_spawn(shash_instance_ctx(inst), salg,
215 shash_crypto_instance(inst));
216 if (err)
217 goto out_free_inst;
218
219 inst->alg.base.cra_priority = alg->cra_priority;
220 inst->alg.base.cra_blocksize = alg->cra_blocksize;
221 inst->alg.base.cra_alignmask = alg->cra_alignmask;
0796ae06 222
0b767b4d 223 ss = ALIGN(ss, alg->cra_alignmask + 1);
8bd1209c 224 inst->alg.digestsize = ds;
0b767b4d 225 inst->alg.statesize = ss;
0796ae06 226
8bd1209c 227 inst->alg.base.cra_ctxsize = sizeof(struct hmac_ctx) +
0b767b4d 228 ALIGN(ss * 2, crypto_tfm_ctx_alignment());
0796ae06 229
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230 inst->alg.base.cra_init = hmac_init_tfm;
231 inst->alg.base.cra_exit = hmac_exit_tfm;
0796ae06 232
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233 inst->alg.init = hmac_init;
234 inst->alg.update = hmac_update;
235 inst->alg.final = hmac_final;
236 inst->alg.finup = hmac_finup;
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237 inst->alg.export = hmac_export;
238 inst->alg.import = hmac_import;
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239 inst->alg.setkey = hmac_setkey;
240
241 err = shash_register_instance(tmpl, inst);
242 if (err) {
243out_free_inst:
244 shash_free_instance(shash_crypto_instance(inst));
245 }
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246
247out_put_alg:
248 crypto_mod_put(alg);
8bd1209c 249 return err;
0796ae06
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250}
251
252static struct crypto_template hmac_tmpl = {
253 .name = "hmac",
8bd1209c
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254 .create = hmac_create,
255 .free = shash_free_instance,
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256 .module = THIS_MODULE,
257};
258
259static int __init hmac_module_init(void)
260{
261 return crypto_register_template(&hmac_tmpl);
262}
263
264static void __exit hmac_module_exit(void)
265{
266 crypto_unregister_template(&hmac_tmpl);
267}
268
269module_init(hmac_module_init);
270module_exit(hmac_module_exit);
271
272MODULE_LICENSE("GPL");
273MODULE_DESCRIPTION("HMAC hash algorithm");