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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Cryptographic API.
3 *
4 * HMAC: Keyed-Hashing for Message Authentication (RFC2104).
5 *
6 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
Herbert Xu0796ae02006-08-21 20:50:52 +10007 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 *
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
Herbert Xu0796ae02006-08-21 20:50:52 +100014 * Software Foundation; either version 2 of the License, or (at your option)
Linus Torvalds1da177e2005-04-16 15:20:36 -070015 * any later version.
16 *
17 */
Herbert Xu0796ae02006-08-21 20:50:52 +100018
Herbert Xu5f7082e2008-08-31 22:21:09 +100019#include <crypto/internal/hash.h>
Herbert Xub2ab4a52007-12-05 20:59:25 +110020#include <crypto/scatterwalk.h>
Herbert Xu0796ae02006-08-21 20:50:52 +100021#include <linux/err.h>
22#include <linux/init.h>
23#include <linux/kernel.h>
24#include <linux/module.h>
David Hardeman378f0582005-09-17 17:55:31 +100025#include <linux/scatterlist.h>
Herbert Xu0796ae02006-08-21 20:50:52 +100026#include <linux/string.h>
27
28struct hmac_ctx {
Herbert Xu0b767b42009-07-24 15:18:41 +080029 struct crypto_shash *hash;
Herbert Xu0796ae02006-08-21 20:50:52 +100030};
Linus Torvalds1da177e2005-04-16 15:20:36 -070031
Herbert Xu0796ae02006-08-21 20:50:52 +100032static inline void *align_ptr(void *p, unsigned int align)
33{
34 return (void *)ALIGN((unsigned long)p, align);
35}
36
Herbert Xu8bd12092009-07-09 12:43:37 +080037static inline struct hmac_ctx *hmac_ctx(struct crypto_shash *tfm)
Herbert Xu0796ae02006-08-21 20:50:52 +100038{
Herbert Xu8bd12092009-07-09 12:43:37 +080039 return align_ptr(crypto_shash_ctx_aligned(tfm) +
Herbert Xu0b767b42009-07-24 15:18:41 +080040 crypto_shash_statesize(tfm) * 2,
Herbert Xu8bd12092009-07-09 12:43:37 +080041 crypto_tfm_ctx_alignment());
Herbert Xu0796ae02006-08-21 20:50:52 +100042}
43
Herbert Xu8bd12092009-07-09 12:43:37 +080044static int hmac_setkey(struct crypto_shash *parent,
Herbert Xu0796ae02006-08-21 20:50:52 +100045 const u8 *inkey, unsigned int keylen)
46{
Herbert Xu8bd12092009-07-09 12:43:37 +080047 int bs = crypto_shash_blocksize(parent);
48 int ds = crypto_shash_digestsize(parent);
Herbert Xu0b767b42009-07-24 15:18:41 +080049 int ss = crypto_shash_statesize(parent);
Herbert Xu8bd12092009-07-09 12:43:37 +080050 char *ipad = crypto_shash_ctx_aligned(parent);
Herbert Xu0b767b42009-07-24 15:18:41 +080051 char *opad = ipad + ss;
52 struct hmac_ctx *ctx = align_ptr(opad + ss,
Herbert Xu8bd12092009-07-09 12:43:37 +080053 crypto_tfm_ctx_alignment());
Herbert Xu0b767b42009-07-24 15:18:41 +080054 struct crypto_shash *hash = ctx->hash;
55 struct {
56 struct shash_desc shash;
57 char ctx[crypto_shash_descsize(hash)];
58 } desc;
Herbert Xu0796ae02006-08-21 20:50:52 +100059 unsigned int i;
60
Herbert Xu0b767b42009-07-24 15:18:41 +080061 desc.shash.tfm = hash;
62 desc.shash.flags = crypto_shash_get_flags(parent) &
63 CRYPTO_TFM_REQ_MAY_SLEEP;
64
Herbert Xu0796ae02006-08-21 20:50:52 +100065 if (keylen > bs) {
Herbert Xu0796ae02006-08-21 20:50:52 +100066 int err;
67
Herbert Xu0b767b42009-07-24 15:18:41 +080068 err = crypto_shash_digest(&desc.shash, inkey, keylen, ipad);
Herbert Xu0796ae02006-08-21 20:50:52 +100069 if (err)
70 return err;
71
Herbert Xu0796ae02006-08-21 20:50:52 +100072 keylen = ds;
Herbert Xu0b767b42009-07-24 15:18:41 +080073 } else
74 memcpy(ipad, inkey, keylen);
Herbert Xu0796ae02006-08-21 20:50:52 +100075
Herbert Xu0796ae02006-08-21 20:50:52 +100076 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
Herbert Xu0b767b42009-07-24 15:18:41 +080084 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);
90}
91
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)
102{
103 struct shash_desc *desc = shash_desc_ctx(pdesc);
104 struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);
105
106 desc->tfm = ctx->hash;
107 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
108
109 return crypto_shash_import(desc, in);
Herbert Xu0796ae02006-08-21 20:50:52 +1000110}
111
Herbert Xu8bd12092009-07-09 12:43:37 +0800112static int hmac_init(struct shash_desc *pdesc)
Herbert Xu0796ae02006-08-21 20:50:52 +1000113{
Herbert Xu0b767b42009-07-24 15:18:41 +0800114 return hmac_import(pdesc, crypto_shash_ctx_aligned(pdesc->tfm));
Herbert Xu0796ae02006-08-21 20:50:52 +1000115}
116
Herbert Xu8bd12092009-07-09 12:43:37 +0800117static int hmac_update(struct shash_desc *pdesc,
118 const u8 *data, unsigned int nbytes)
Herbert Xu0796ae02006-08-21 20:50:52 +1000119{
Herbert Xu8bd12092009-07-09 12:43:37 +0800120 struct shash_desc *desc = shash_desc_ctx(pdesc);
Herbert Xu0796ae02006-08-21 20:50:52 +1000121
Herbert Xu8bd12092009-07-09 12:43:37 +0800122 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
Herbert Xu0796ae02006-08-21 20:50:52 +1000123
Herbert Xu8bd12092009-07-09 12:43:37 +0800124 return crypto_shash_update(desc, data, nbytes);
Herbert Xu0796ae02006-08-21 20:50:52 +1000125}
126
Herbert Xu8bd12092009-07-09 12:43:37 +0800127static int hmac_final(struct shash_desc *pdesc, u8 *out)
Herbert Xu0796ae02006-08-21 20:50:52 +1000128{
Herbert Xu8bd12092009-07-09 12:43:37 +0800129 struct crypto_shash *parent = pdesc->tfm;
Herbert Xu8bd12092009-07-09 12:43:37 +0800130 int ds = crypto_shash_digestsize(parent);
Herbert Xu0b767b42009-07-24 15:18:41 +0800131 int ss = crypto_shash_statesize(parent);
132 char *opad = crypto_shash_ctx_aligned(parent) + ss;
Herbert Xu8bd12092009-07-09 12:43:37 +0800133 struct shash_desc *desc = shash_desc_ctx(pdesc);
Herbert Xu0796ae02006-08-21 20:50:52 +1000134
Herbert Xu8bd12092009-07-09 12:43:37 +0800135 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
Herbert Xu0796ae02006-08-21 20:50:52 +1000136
Herbert Xu0b767b42009-07-24 15:18:41 +0800137 return crypto_shash_final(desc, out) ?:
138 crypto_shash_import(desc, opad) ?:
139 crypto_shash_finup(desc, out, ds, out);
Herbert Xu0796ae02006-08-21 20:50:52 +1000140}
141
Herbert Xu8bd12092009-07-09 12:43:37 +0800142static int hmac_finup(struct shash_desc *pdesc, const u8 *data,
143 unsigned int nbytes, u8 *out)
Herbert Xu0796ae02006-08-21 20:50:52 +1000144{
Herbert Xu8bd12092009-07-09 12:43:37 +0800145
146 struct crypto_shash *parent = pdesc->tfm;
Herbert Xu8bd12092009-07-09 12:43:37 +0800147 int ds = crypto_shash_digestsize(parent);
Herbert Xu0b767b42009-07-24 15:18:41 +0800148 int ss = crypto_shash_statesize(parent);
149 char *opad = crypto_shash_ctx_aligned(parent) + ss;
Herbert Xu8bd12092009-07-09 12:43:37 +0800150 struct shash_desc *desc = shash_desc_ctx(pdesc);
Herbert Xu0796ae02006-08-21 20:50:52 +1000151
Herbert Xu8bd12092009-07-09 12:43:37 +0800152 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
Herbert Xu0796ae02006-08-21 20:50:52 +1000153
Herbert Xu0b767b42009-07-24 15:18:41 +0800154 return crypto_shash_finup(desc, data, nbytes, out) ?:
155 crypto_shash_import(desc, opad) ?:
156 crypto_shash_finup(desc, out, ds, out);
Herbert Xu0796ae02006-08-21 20:50:52 +1000157}
158
159static int hmac_init_tfm(struct crypto_tfm *tfm)
160{
Herbert Xu8bd12092009-07-09 12:43:37 +0800161 struct crypto_shash *parent = __crypto_shash_cast(tfm);
162 struct crypto_shash *hash;
Herbert Xu0796ae02006-08-21 20:50:52 +1000163 struct crypto_instance *inst = (void *)tfm->__crt_alg;
Herbert Xu8bd12092009-07-09 12:43:37 +0800164 struct crypto_shash_spawn *spawn = crypto_instance_ctx(inst);
165 struct hmac_ctx *ctx = hmac_ctx(parent);
Herbert Xu0796ae02006-08-21 20:50:52 +1000166
Herbert Xu8bd12092009-07-09 12:43:37 +0800167 hash = crypto_spawn_shash(spawn);
Herbert Xu2e306ee2006-12-17 10:05:58 +1100168 if (IS_ERR(hash))
169 return PTR_ERR(hash);
Herbert Xu0796ae02006-08-21 20:50:52 +1000170
Herbert Xu8bd12092009-07-09 12:43:37 +0800171 parent->descsize = sizeof(struct shash_desc) +
172 crypto_shash_descsize(hash);
173
Herbert Xu0b767b42009-07-24 15:18:41 +0800174 ctx->hash = hash;
Herbert Xu0796ae02006-08-21 20:50:52 +1000175 return 0;
176}
177
178static void hmac_exit_tfm(struct crypto_tfm *tfm)
179{
Herbert Xu8bd12092009-07-09 12:43:37 +0800180 struct hmac_ctx *ctx = hmac_ctx(__crypto_shash_cast(tfm));
Herbert Xu0b767b42009-07-24 15:18:41 +0800181 crypto_free_shash(ctx->hash);
Herbert Xu0796ae02006-08-21 20:50:52 +1000182}
183
Herbert Xu8bd12092009-07-09 12:43:37 +0800184static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
Herbert Xu0796ae02006-08-21 20:50:52 +1000185{
Herbert Xu8bd12092009-07-09 12:43:37 +0800186 struct shash_instance *inst;
Herbert Xu0796ae02006-08-21 20:50:52 +1000187 struct crypto_alg *alg;
Herbert Xu8bd12092009-07-09 12:43:37 +0800188 struct shash_alg *salg;
Herbert Xuebc610e2007-01-01 18:37:02 +1100189 int err;
Herbert Xuca786dc2008-07-07 20:23:56 +0800190 int ds;
Herbert Xu0b767b42009-07-24 15:18:41 +0800191 int ss;
Herbert Xu0796ae02006-08-21 20:50:52 +1000192
Herbert Xu8bd12092009-07-09 12:43:37 +0800193 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
Herbert Xuebc610e2007-01-01 18:37:02 +1100194 if (err)
Herbert Xu8bd12092009-07-09 12:43:37 +0800195 return err;
Herbert Xuebc610e2007-01-01 18:37:02 +1100196
Herbert Xu8bd12092009-07-09 12:43:37 +0800197 salg = shash_attr_alg(tb[1], 0, 0);
198 if (IS_ERR(salg))
199 return PTR_ERR(salg);
Eric Biggersef368632017-11-28 18:01:38 -0800200 alg = &salg->base;
Herbert Xu0796ae02006-08-21 20:50:52 +1000201
Eric Biggersef368632017-11-28 18:01:38 -0800202 /* The underlying hash algorithm must be unkeyed */
Herbert Xu8bd12092009-07-09 12:43:37 +0800203 err = -EINVAL;
Eric Biggersef368632017-11-28 18:01:38 -0800204 if (crypto_shash_alg_has_setkey(salg))
205 goto out_put_alg;
206
Herbert Xu8bd12092009-07-09 12:43:37 +0800207 ds = salg->digestsize;
Herbert Xu0b767b42009-07-24 15:18:41 +0800208 ss = salg->statesize;
Herbert Xu0b767b42009-07-24 15:18:41 +0800209 if (ds > alg->cra_blocksize ||
210 ss < alg->cra_blocksize)
Herbert Xuca786dc2008-07-07 20:23:56 +0800211 goto out_put_alg;
212
Herbert Xu8bd12092009-07-09 12:43:37 +0800213 inst = shash_alloc_instance("hmac", alg);
Herbert Xu3b3fc322009-07-15 16:52:55 +0800214 err = PTR_ERR(inst);
Herbert Xu0796ae02006-08-21 20:50:52 +1000215 if (IS_ERR(inst))
216 goto out_put_alg;
217
Herbert Xu8bd12092009-07-09 12:43:37 +0800218 err = crypto_init_shash_spawn(shash_instance_ctx(inst), salg,
219 shash_crypto_instance(inst));
220 if (err)
221 goto out_free_inst;
Herbert Xu0796ae02006-08-21 20:50:52 +1000222
Herbert Xu8bd12092009-07-09 12:43:37 +0800223 inst->alg.base.cra_priority = alg->cra_priority;
224 inst->alg.base.cra_blocksize = alg->cra_blocksize;
225 inst->alg.base.cra_alignmask = alg->cra_alignmask;
Herbert Xu0796ae02006-08-21 20:50:52 +1000226
Herbert Xu0b767b42009-07-24 15:18:41 +0800227 ss = ALIGN(ss, alg->cra_alignmask + 1);
Herbert Xu8bd12092009-07-09 12:43:37 +0800228 inst->alg.digestsize = ds;
Herbert Xu0b767b42009-07-24 15:18:41 +0800229 inst->alg.statesize = ss;
Herbert Xu0796ae02006-08-21 20:50:52 +1000230
Herbert Xu8bd12092009-07-09 12:43:37 +0800231 inst->alg.base.cra_ctxsize = sizeof(struct hmac_ctx) +
Herbert Xu0b767b42009-07-24 15:18:41 +0800232 ALIGN(ss * 2, crypto_tfm_ctx_alignment());
Herbert Xu0796ae02006-08-21 20:50:52 +1000233
Herbert Xu8bd12092009-07-09 12:43:37 +0800234 inst->alg.base.cra_init = hmac_init_tfm;
235 inst->alg.base.cra_exit = hmac_exit_tfm;
236
237 inst->alg.init = hmac_init;
238 inst->alg.update = hmac_update;
239 inst->alg.final = hmac_final;
240 inst->alg.finup = hmac_finup;
Herbert Xu0b767b42009-07-24 15:18:41 +0800241 inst->alg.export = hmac_export;
242 inst->alg.import = hmac_import;
Herbert Xu8bd12092009-07-09 12:43:37 +0800243 inst->alg.setkey = hmac_setkey;
244
245 err = shash_register_instance(tmpl, inst);
246 if (err) {
247out_free_inst:
248 shash_free_instance(shash_crypto_instance(inst));
249 }
Herbert Xu0796ae02006-08-21 20:50:52 +1000250
251out_put_alg:
252 crypto_mod_put(alg);
Herbert Xu8bd12092009-07-09 12:43:37 +0800253 return err;
Herbert Xu0796ae02006-08-21 20:50:52 +1000254}
255
256static struct crypto_template hmac_tmpl = {
257 .name = "hmac",
Herbert Xu8bd12092009-07-09 12:43:37 +0800258 .create = hmac_create,
259 .free = shash_free_instance,
Herbert Xu0796ae02006-08-21 20:50:52 +1000260 .module = THIS_MODULE,
261};
262
263static int __init hmac_module_init(void)
264{
265 return crypto_register_template(&hmac_tmpl);
266}
267
268static void __exit hmac_module_exit(void)
269{
270 crypto_unregister_template(&hmac_tmpl);
271}
272
273module_init(hmac_module_init);
274module_exit(hmac_module_exit);
275
276MODULE_LICENSE("GPL");
277MODULE_DESCRIPTION("HMAC hash algorithm");