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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;
Jan-Simon Möllerffb32e92012-07-02 13:47:40 +020055 SHASH_DESC_ON_STACK(shash, hash);
Herbert Xu0796ae02006-08-21 20:50:52 +100056 unsigned int i;
57
Jan-Simon Möllerffb32e92012-07-02 13:47:40 +020058 shash->tfm = hash;
59 shash->flags = crypto_shash_get_flags(parent)
60 & CRYPTO_TFM_REQ_MAY_SLEEP;
Herbert Xu0b767b42009-07-24 15:18:41 +080061
Herbert Xu0796ae02006-08-21 20:50:52 +100062 if (keylen > bs) {
Herbert Xu0796ae02006-08-21 20:50:52 +100063 int err;
64
Jan-Simon Möllerffb32e92012-07-02 13:47:40 +020065 err = crypto_shash_digest(shash, inkey, keylen, ipad);
Herbert Xu0796ae02006-08-21 20:50:52 +100066 if (err)
67 return err;
68
Herbert Xu0796ae02006-08-21 20:50:52 +100069 keylen = ds;
Herbert Xu0b767b42009-07-24 15:18:41 +080070 } else
71 memcpy(ipad, inkey, keylen);
Herbert Xu0796ae02006-08-21 20:50:52 +100072
Herbert Xu0796ae02006-08-21 20:50:52 +100073 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
Jan-Simon Möllerffb32e92012-07-02 13:47:40 +020081 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);
Herbert Xu0b767b42009-07-24 15:18:41 +080087}
88
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)
99{
100 struct shash_desc *desc = shash_desc_ctx(pdesc);
101 struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);
102
103 desc->tfm = ctx->hash;
104 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
105
106 return crypto_shash_import(desc, in);
Herbert Xu0796ae02006-08-21 20:50:52 +1000107}
108
Herbert Xu8bd12092009-07-09 12:43:37 +0800109static int hmac_init(struct shash_desc *pdesc)
Herbert Xu0796ae02006-08-21 20:50:52 +1000110{
Herbert Xu0b767b42009-07-24 15:18:41 +0800111 return hmac_import(pdesc, crypto_shash_ctx_aligned(pdesc->tfm));
Herbert Xu0796ae02006-08-21 20:50:52 +1000112}
113
Herbert Xu8bd12092009-07-09 12:43:37 +0800114static int hmac_update(struct shash_desc *pdesc,
115 const u8 *data, unsigned int nbytes)
Herbert Xu0796ae02006-08-21 20:50:52 +1000116{
Herbert Xu8bd12092009-07-09 12:43:37 +0800117 struct shash_desc *desc = shash_desc_ctx(pdesc);
Herbert Xu0796ae02006-08-21 20:50:52 +1000118
Herbert Xu8bd12092009-07-09 12:43:37 +0800119 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
Herbert Xu0796ae02006-08-21 20:50:52 +1000120
Herbert Xu8bd12092009-07-09 12:43:37 +0800121 return crypto_shash_update(desc, data, nbytes);
Herbert Xu0796ae02006-08-21 20:50:52 +1000122}
123
Herbert Xu8bd12092009-07-09 12:43:37 +0800124static int hmac_final(struct shash_desc *pdesc, u8 *out)
Herbert Xu0796ae02006-08-21 20:50:52 +1000125{
Herbert Xu8bd12092009-07-09 12:43:37 +0800126 struct crypto_shash *parent = pdesc->tfm;
Herbert Xu8bd12092009-07-09 12:43:37 +0800127 int ds = crypto_shash_digestsize(parent);
Herbert Xu0b767b42009-07-24 15:18:41 +0800128 int ss = crypto_shash_statesize(parent);
129 char *opad = crypto_shash_ctx_aligned(parent) + ss;
Herbert Xu8bd12092009-07-09 12:43:37 +0800130 struct shash_desc *desc = shash_desc_ctx(pdesc);
Herbert Xu0796ae02006-08-21 20:50:52 +1000131
Herbert Xu8bd12092009-07-09 12:43:37 +0800132 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
Herbert Xu0796ae02006-08-21 20:50:52 +1000133
Herbert Xu0b767b42009-07-24 15:18:41 +0800134 return crypto_shash_final(desc, out) ?:
135 crypto_shash_import(desc, opad) ?:
136 crypto_shash_finup(desc, out, ds, out);
Herbert Xu0796ae02006-08-21 20:50:52 +1000137}
138
Herbert Xu8bd12092009-07-09 12:43:37 +0800139static int hmac_finup(struct shash_desc *pdesc, const u8 *data,
140 unsigned int nbytes, u8 *out)
Herbert Xu0796ae02006-08-21 20:50:52 +1000141{
Herbert Xu8bd12092009-07-09 12:43:37 +0800142
143 struct crypto_shash *parent = pdesc->tfm;
Herbert Xu8bd12092009-07-09 12:43:37 +0800144 int ds = crypto_shash_digestsize(parent);
Herbert Xu0b767b42009-07-24 15:18:41 +0800145 int ss = crypto_shash_statesize(parent);
146 char *opad = crypto_shash_ctx_aligned(parent) + ss;
Herbert Xu8bd12092009-07-09 12:43:37 +0800147 struct shash_desc *desc = shash_desc_ctx(pdesc);
Herbert Xu0796ae02006-08-21 20:50:52 +1000148
Herbert Xu8bd12092009-07-09 12:43:37 +0800149 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
Herbert Xu0796ae02006-08-21 20:50:52 +1000150
Herbert Xu0b767b42009-07-24 15:18:41 +0800151 return crypto_shash_finup(desc, data, nbytes, out) ?:
152 crypto_shash_import(desc, opad) ?:
153 crypto_shash_finup(desc, out, ds, out);
Herbert Xu0796ae02006-08-21 20:50:52 +1000154}
155
156static int hmac_init_tfm(struct crypto_tfm *tfm)
157{
Herbert Xu8bd12092009-07-09 12:43:37 +0800158 struct crypto_shash *parent = __crypto_shash_cast(tfm);
159 struct crypto_shash *hash;
Herbert Xu0796ae02006-08-21 20:50:52 +1000160 struct crypto_instance *inst = (void *)tfm->__crt_alg;
Herbert Xu8bd12092009-07-09 12:43:37 +0800161 struct crypto_shash_spawn *spawn = crypto_instance_ctx(inst);
162 struct hmac_ctx *ctx = hmac_ctx(parent);
Herbert Xu0796ae02006-08-21 20:50:52 +1000163
Herbert Xu8bd12092009-07-09 12:43:37 +0800164 hash = crypto_spawn_shash(spawn);
Herbert Xu2e306ee2006-12-17 10:05:58 +1100165 if (IS_ERR(hash))
166 return PTR_ERR(hash);
Herbert Xu0796ae02006-08-21 20:50:52 +1000167
Herbert Xu8bd12092009-07-09 12:43:37 +0800168 parent->descsize = sizeof(struct shash_desc) +
169 crypto_shash_descsize(hash);
170
Herbert Xu0b767b42009-07-24 15:18:41 +0800171 ctx->hash = hash;
Herbert Xu0796ae02006-08-21 20:50:52 +1000172 return 0;
173}
174
175static void hmac_exit_tfm(struct crypto_tfm *tfm)
176{
Herbert Xu8bd12092009-07-09 12:43:37 +0800177 struct hmac_ctx *ctx = hmac_ctx(__crypto_shash_cast(tfm));
Herbert Xu0b767b42009-07-24 15:18:41 +0800178 crypto_free_shash(ctx->hash);
Herbert Xu0796ae02006-08-21 20:50:52 +1000179}
180
Herbert Xu8bd12092009-07-09 12:43:37 +0800181static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
Herbert Xu0796ae02006-08-21 20:50:52 +1000182{
Herbert Xu8bd12092009-07-09 12:43:37 +0800183 struct shash_instance *inst;
Herbert Xu0796ae02006-08-21 20:50:52 +1000184 struct crypto_alg *alg;
Herbert Xu8bd12092009-07-09 12:43:37 +0800185 struct shash_alg *salg;
Herbert Xuebc610e2007-01-01 18:37:02 +1100186 int err;
Herbert Xuca786dc2008-07-07 20:23:56 +0800187 int ds;
Herbert Xu0b767b42009-07-24 15:18:41 +0800188 int ss;
Herbert Xu0796ae02006-08-21 20:50:52 +1000189
Herbert Xu8bd12092009-07-09 12:43:37 +0800190 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
Herbert Xuebc610e2007-01-01 18:37:02 +1100191 if (err)
Herbert Xu8bd12092009-07-09 12:43:37 +0800192 return err;
Herbert Xuebc610e2007-01-01 18:37:02 +1100193
Herbert Xu8bd12092009-07-09 12:43:37 +0800194 salg = shash_attr_alg(tb[1], 0, 0);
195 if (IS_ERR(salg))
196 return PTR_ERR(salg);
Eric Biggers43259d02017-11-28 18:01:38 -0800197 alg = &salg->base;
Herbert Xu0796ae02006-08-21 20:50:52 +1000198
Eric Biggers43259d02017-11-28 18:01:38 -0800199 /* The underlying hash algorithm must be unkeyed */
Herbert Xu8bd12092009-07-09 12:43:37 +0800200 err = -EINVAL;
Eric Biggers43259d02017-11-28 18:01:38 -0800201 if (crypto_shash_alg_has_setkey(salg))
202 goto out_put_alg;
203
Herbert Xu8bd12092009-07-09 12:43:37 +0800204 ds = salg->digestsize;
Herbert Xu0b767b42009-07-24 15:18:41 +0800205 ss = salg->statesize;
Herbert Xu0b767b42009-07-24 15:18:41 +0800206 if (ds > alg->cra_blocksize ||
207 ss < alg->cra_blocksize)
Herbert Xuca786dc2008-07-07 20:23:56 +0800208 goto out_put_alg;
209
Herbert Xu8bd12092009-07-09 12:43:37 +0800210 inst = shash_alloc_instance("hmac", alg);
Herbert Xu3b3fc322009-07-15 16:52:55 +0800211 err = PTR_ERR(inst);
Herbert Xu0796ae02006-08-21 20:50:52 +1000212 if (IS_ERR(inst))
213 goto out_put_alg;
214
Herbert Xu8bd12092009-07-09 12:43:37 +0800215 err = crypto_init_shash_spawn(shash_instance_ctx(inst), salg,
216 shash_crypto_instance(inst));
217 if (err)
218 goto out_free_inst;
Herbert Xu0796ae02006-08-21 20:50:52 +1000219
Herbert Xu8bd12092009-07-09 12:43:37 +0800220 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;
Herbert Xu0796ae02006-08-21 20:50:52 +1000223
Herbert Xu0b767b42009-07-24 15:18:41 +0800224 ss = ALIGN(ss, alg->cra_alignmask + 1);
Herbert Xu8bd12092009-07-09 12:43:37 +0800225 inst->alg.digestsize = ds;
Herbert Xu0b767b42009-07-24 15:18:41 +0800226 inst->alg.statesize = ss;
Herbert Xu0796ae02006-08-21 20:50:52 +1000227
Herbert Xu8bd12092009-07-09 12:43:37 +0800228 inst->alg.base.cra_ctxsize = sizeof(struct hmac_ctx) +
Herbert Xu0b767b42009-07-24 15:18:41 +0800229 ALIGN(ss * 2, crypto_tfm_ctx_alignment());
Herbert Xu0796ae02006-08-21 20:50:52 +1000230
Herbert Xu8bd12092009-07-09 12:43:37 +0800231 inst->alg.base.cra_init = hmac_init_tfm;
232 inst->alg.base.cra_exit = hmac_exit_tfm;
233
234 inst->alg.init = hmac_init;
235 inst->alg.update = hmac_update;
236 inst->alg.final = hmac_final;
237 inst->alg.finup = hmac_finup;
Herbert Xu0b767b42009-07-24 15:18:41 +0800238 inst->alg.export = hmac_export;
239 inst->alg.import = hmac_import;
Herbert Xu8bd12092009-07-09 12:43:37 +0800240 inst->alg.setkey = hmac_setkey;
241
242 err = shash_register_instance(tmpl, inst);
243 if (err) {
244out_free_inst:
245 shash_free_instance(shash_crypto_instance(inst));
246 }
Herbert Xu0796ae02006-08-21 20:50:52 +1000247
248out_put_alg:
249 crypto_mod_put(alg);
Herbert Xu8bd12092009-07-09 12:43:37 +0800250 return err;
Herbert Xu0796ae02006-08-21 20:50:52 +1000251}
252
253static struct crypto_template hmac_tmpl = {
254 .name = "hmac",
Herbert Xu8bd12092009-07-09 12:43:37 +0800255 .create = hmac_create,
256 .free = shash_free_instance,
Herbert Xu0796ae02006-08-21 20:50:52 +1000257 .module = THIS_MODULE,
258};
259
260static int __init hmac_module_init(void)
261{
262 return crypto_register_template(&hmac_tmpl);
263}
264
265static void __exit hmac_module_exit(void)
266{
267 crypto_unregister_template(&hmac_tmpl);
268}
269
270module_init(hmac_module_init);
271module_exit(hmac_module_exit);
272
273MODULE_LICENSE("GPL");
274MODULE_DESCRIPTION("HMAC hash algorithm");
Kees Cook4943ba12014-11-24 16:32:38 -0800275MODULE_ALIAS_CRYPTO("hmac");