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/hmac.h>
20 #include <crypto/internal/hash.h>
21 #include <crypto/scatterwalk.h>
22 #include <linux/err.h>
23 #include <linux/init.h>
24 #include <linux/kernel.h>
25 #include <linux/module.h>
26 #include <linux/scatterlist.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;
56 SHASH_DESC_ON_STACK(shash, hash);
64 err = crypto_shash_digest(shash, inkey, keylen, ipad);
70 memcpy(ipad, inkey, keylen);
72 memset(ipad + keylen, 0, bs - keylen);
73 memcpy(opad, ipad, bs);
75 for (i = 0; i < bs; i++) {
76 ipad[i] ^= HMAC_IPAD_VALUE;
77 opad[i] ^= HMAC_OPAD_VALUE;
80 return crypto_shash_init(shash) ?:
81 crypto_shash_update(shash, ipad, bs) ?:
82 crypto_shash_export(shash, ipad) ?:
83 crypto_shash_init(shash) ?:
84 crypto_shash_update(shash, opad, bs) ?:
85 crypto_shash_export(shash, opad);
88 static int hmac_export(struct shash_desc *pdesc, void *out)
90 struct shash_desc *desc = shash_desc_ctx(pdesc);
92 return crypto_shash_export(desc, out);
95 static int hmac_import(struct shash_desc *pdesc, const void *in)
97 struct shash_desc *desc = shash_desc_ctx(pdesc);
98 struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);
100 desc->tfm = ctx->hash;
102 return crypto_shash_import(desc, in);
105 static int hmac_init(struct shash_desc *pdesc)
107 return hmac_import(pdesc, crypto_shash_ctx_aligned(pdesc->tfm));
110 static int hmac_update(struct shash_desc *pdesc,
111 const u8 *data, unsigned int nbytes)
113 struct shash_desc *desc = shash_desc_ctx(pdesc);
115 return crypto_shash_update(desc, data, nbytes);
118 static int hmac_final(struct shash_desc *pdesc, u8 *out)
120 struct crypto_shash *parent = pdesc->tfm;
121 int ds = crypto_shash_digestsize(parent);
122 int ss = crypto_shash_statesize(parent);
123 char *opad = crypto_shash_ctx_aligned(parent) + ss;
124 struct shash_desc *desc = shash_desc_ctx(pdesc);
126 return crypto_shash_final(desc, out) ?:
127 crypto_shash_import(desc, opad) ?:
128 crypto_shash_finup(desc, out, ds, out);
131 static int hmac_finup(struct shash_desc *pdesc, const u8 *data,
132 unsigned int nbytes, u8 *out)
135 struct crypto_shash *parent = pdesc->tfm;
136 int ds = crypto_shash_digestsize(parent);
137 int ss = crypto_shash_statesize(parent);
138 char *opad = crypto_shash_ctx_aligned(parent) + ss;
139 struct shash_desc *desc = shash_desc_ctx(pdesc);
141 return crypto_shash_finup(desc, data, nbytes, out) ?:
142 crypto_shash_import(desc, opad) ?:
143 crypto_shash_finup(desc, out, ds, out);
146 static int hmac_init_tfm(struct crypto_tfm *tfm)
148 struct crypto_shash *parent = __crypto_shash_cast(tfm);
149 struct crypto_shash *hash;
150 struct crypto_instance *inst = (void *)tfm->__crt_alg;
151 struct crypto_shash_spawn *spawn = crypto_instance_ctx(inst);
152 struct hmac_ctx *ctx = hmac_ctx(parent);
154 hash = crypto_spawn_shash(spawn);
156 return PTR_ERR(hash);
158 parent->descsize = sizeof(struct shash_desc) +
159 crypto_shash_descsize(hash);
160 if (WARN_ON(parent->descsize > HASH_MAX_DESCSIZE))
167 static void hmac_exit_tfm(struct crypto_tfm *tfm)
169 struct hmac_ctx *ctx = hmac_ctx(__crypto_shash_cast(tfm));
170 crypto_free_shash(ctx->hash);
173 static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
175 struct shash_instance *inst;
176 struct crypto_alg *alg;
177 struct shash_alg *salg;
182 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
186 salg = shash_attr_alg(tb[1], 0, 0);
188 return PTR_ERR(salg);
191 /* The underlying hash algorithm must be unkeyed */
193 if (crypto_shash_alg_has_setkey(salg))
196 ds = salg->digestsize;
197 ss = salg->statesize;
198 if (ds > alg->cra_blocksize ||
199 ss < alg->cra_blocksize)
202 inst = shash_alloc_instance("hmac", alg);
207 err = crypto_init_shash_spawn(shash_instance_ctx(inst), salg,
208 shash_crypto_instance(inst));
212 inst->alg.base.cra_priority = alg->cra_priority;
213 inst->alg.base.cra_blocksize = alg->cra_blocksize;
214 inst->alg.base.cra_alignmask = alg->cra_alignmask;
216 ss = ALIGN(ss, alg->cra_alignmask + 1);
217 inst->alg.digestsize = ds;
218 inst->alg.statesize = ss;
220 inst->alg.base.cra_ctxsize = sizeof(struct hmac_ctx) +
221 ALIGN(ss * 2, crypto_tfm_ctx_alignment());
223 inst->alg.base.cra_init = hmac_init_tfm;
224 inst->alg.base.cra_exit = hmac_exit_tfm;
226 inst->alg.init = hmac_init;
227 inst->alg.update = hmac_update;
228 inst->alg.final = hmac_final;
229 inst->alg.finup = hmac_finup;
230 inst->alg.export = hmac_export;
231 inst->alg.import = hmac_import;
232 inst->alg.setkey = hmac_setkey;
234 err = shash_register_instance(tmpl, inst);
237 shash_free_instance(shash_crypto_instance(inst));
245 static struct crypto_template hmac_tmpl = {
247 .create = hmac_create,
248 .free = shash_free_instance,
249 .module = THIS_MODULE,
252 static int __init hmac_module_init(void)
254 return crypto_register_template(&hmac_tmpl);
257 static void __exit hmac_module_exit(void)
259 crypto_unregister_template(&hmac_tmpl);
262 subsys_initcall(hmac_module_init);
263 module_exit(hmac_module_exit);
265 MODULE_LICENSE("GPL");
266 MODULE_DESCRIPTION("HMAC hash algorithm");
267 MODULE_ALIAS_CRYPTO("hmac");