4 * HMAC: Keyed-Hashing for Message Authentication (RFC2104).
6 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
7 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
9 * The HMAC implementation is derived from USAGI.
10 * Copyright (c) 2002 Kazunori Miyazawa <miyazawa@linux-ipv6.org> / USAGI
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)
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/slab.h>
27 #include <linux/string.h>
30 struct crypto_shash *hash;
33 static inline void *align_ptr(void *p, unsigned int align)
35 return (void *)ALIGN((unsigned long)p, align);
38 static inline struct hmac_ctx *hmac_ctx(struct crypto_shash *tfm)
40 return align_ptr(crypto_shash_ctx_aligned(tfm) +
41 crypto_shash_statesize(tfm) * 2,
42 crypto_tfm_ctx_alignment());
45 static int hmac_setkey(struct crypto_shash *parent,
46 const u8 *inkey, unsigned int keylen)
48 int bs = crypto_shash_blocksize(parent);
49 int ds = crypto_shash_digestsize(parent);
50 int ss = crypto_shash_statesize(parent);
51 char *ipad = crypto_shash_ctx_aligned(parent);
52 char *opad = ipad + ss;
53 struct hmac_ctx *ctx = align_ptr(opad + ss,
54 crypto_tfm_ctx_alignment());
55 struct crypto_shash *hash = ctx->hash;
57 struct shash_desc shash;
58 char ctx[crypto_shash_descsize(hash)];
62 desc.shash.tfm = hash;
63 desc.shash.flags = crypto_shash_get_flags(parent) &
64 CRYPTO_TFM_REQ_MAY_SLEEP;
69 err = crypto_shash_digest(&desc.shash, inkey, keylen, ipad);
75 memcpy(ipad, inkey, keylen);
77 memset(ipad + keylen, 0, bs - keylen);
78 memcpy(opad, ipad, bs);
80 for (i = 0; i < bs; i++) {
85 return crypto_shash_init(&desc.shash) ?:
86 crypto_shash_update(&desc.shash, ipad, bs) ?:
87 crypto_shash_export(&desc.shash, ipad) ?:
88 crypto_shash_init(&desc.shash) ?:
89 crypto_shash_update(&desc.shash, opad, bs) ?:
90 crypto_shash_export(&desc.shash, opad);
93 static int hmac_export(struct shash_desc *pdesc, void *out)
95 struct shash_desc *desc = shash_desc_ctx(pdesc);
97 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
99 return crypto_shash_export(desc, out);
102 static int hmac_import(struct shash_desc *pdesc, const void *in)
104 struct shash_desc *desc = shash_desc_ctx(pdesc);
105 struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);
107 desc->tfm = ctx->hash;
108 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
110 return crypto_shash_import(desc, in);
113 static int hmac_init(struct shash_desc *pdesc)
115 return hmac_import(pdesc, crypto_shash_ctx_aligned(pdesc->tfm));
118 static int hmac_update(struct shash_desc *pdesc,
119 const u8 *data, unsigned int nbytes)
121 struct shash_desc *desc = shash_desc_ctx(pdesc);
123 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
125 return crypto_shash_update(desc, data, nbytes);
128 static int hmac_final(struct shash_desc *pdesc, u8 *out)
130 struct crypto_shash *parent = pdesc->tfm;
131 int ds = crypto_shash_digestsize(parent);
132 int ss = crypto_shash_statesize(parent);
133 char *opad = crypto_shash_ctx_aligned(parent) + ss;
134 struct shash_desc *desc = shash_desc_ctx(pdesc);
136 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
138 return crypto_shash_final(desc, out) ?:
139 crypto_shash_import(desc, opad) ?:
140 crypto_shash_finup(desc, out, ds, out);
143 static int hmac_finup(struct shash_desc *pdesc, const u8 *data,
144 unsigned int nbytes, u8 *out)
147 struct crypto_shash *parent = pdesc->tfm;
148 int ds = crypto_shash_digestsize(parent);
149 int ss = crypto_shash_statesize(parent);
150 char *opad = crypto_shash_ctx_aligned(parent) + ss;
151 struct shash_desc *desc = shash_desc_ctx(pdesc);
153 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
155 return crypto_shash_finup(desc, data, nbytes, out) ?:
156 crypto_shash_import(desc, opad) ?:
157 crypto_shash_finup(desc, out, ds, out);
160 static int hmac_init_tfm(struct crypto_tfm *tfm)
162 struct crypto_shash *parent = __crypto_shash_cast(tfm);
163 struct crypto_shash *hash;
164 struct crypto_instance *inst = (void *)tfm->__crt_alg;
165 struct crypto_shash_spawn *spawn = crypto_instance_ctx(inst);
166 struct hmac_ctx *ctx = hmac_ctx(parent);
168 hash = crypto_spawn_shash(spawn);
170 return PTR_ERR(hash);
172 parent->descsize = sizeof(struct shash_desc) +
173 crypto_shash_descsize(hash);
179 static void hmac_exit_tfm(struct crypto_tfm *tfm)
181 struct hmac_ctx *ctx = hmac_ctx(__crypto_shash_cast(tfm));
182 crypto_free_shash(ctx->hash);
185 static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
187 struct shash_instance *inst;
188 struct crypto_alg *alg;
189 struct shash_alg *salg;
194 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
198 salg = shash_attr_alg(tb[1], 0, 0);
200 return PTR_ERR(salg);
203 ds = salg->digestsize;
204 ss = salg->statesize;
206 if (ds > alg->cra_blocksize ||
207 ss < alg->cra_blocksize)
210 inst = shash_alloc_instance("hmac", alg);
215 err = crypto_init_shash_spawn(shash_instance_ctx(inst), salg,
216 shash_crypto_instance(inst));
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;
224 ss = ALIGN(ss, alg->cra_alignmask + 1);
225 inst->alg.digestsize = ds;
226 inst->alg.statesize = ss;
228 inst->alg.base.cra_ctxsize = sizeof(struct hmac_ctx) +
229 ALIGN(ss * 2, crypto_tfm_ctx_alignment());
231 inst->alg.base.cra_init = hmac_init_tfm;
232 inst->alg.base.cra_exit = hmac_exit_tfm;
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;
242 err = shash_register_instance(tmpl, inst);
245 shash_free_instance(shash_crypto_instance(inst));
253 static struct crypto_template hmac_tmpl = {
255 .create = hmac_create,
256 .free = shash_free_instance,
257 .module = THIS_MODULE,
260 static int __init hmac_module_init(void)
262 return crypto_register_template(&hmac_tmpl);
265 static void __exit hmac_module_exit(void)
267 crypto_unregister_template(&hmac_tmpl);
270 module_init(hmac_module_init);
271 module_exit(hmac_module_exit);
273 MODULE_LICENSE("GPL");
274 MODULE_DESCRIPTION("HMAC hash algorithm");