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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>
28
29struct hmac_ctx {
30 struct crypto_shash *hash;
31};
32
33static inline void *align_ptr(void *p, unsigned int align)
34{
35 return (void *)ALIGN((unsigned long)p, align);
36}
37
38static inline struct hmac_ctx *hmac_ctx(struct crypto_shash *tfm)
39{
40 return align_ptr(crypto_shash_ctx_aligned(tfm) +
41 crypto_shash_statesize(tfm) * 2,
42 crypto_tfm_ctx_alignment());
43}
44
45static int hmac_setkey(struct crypto_shash *parent,
46 const u8 *inkey, unsigned int keylen)
47{
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 struct {
57 struct shash_desc shash;
58 char ctx[crypto_shash_descsize(hash)];
59 } desc;
60 unsigned int i;
61
62 desc.shash.tfm = hash;
63 desc.shash.flags = crypto_shash_get_flags(parent) &
64 CRYPTO_TFM_REQ_MAY_SLEEP;
65
66 if (keylen > bs) {
67 int err;
68
69 err = crypto_shash_digest(&desc.shash, inkey, keylen, ipad);
70 if (err)
71 return err;
72
73 keylen = ds;
74 } else
75 memcpy(ipad, inkey, keylen);
76
77 memset(ipad + keylen, 0, bs - keylen);
78 memcpy(opad, ipad, bs);
79
80 for (i = 0; i < bs; i++) {
81 ipad[i] ^= 0x36;
82 opad[i] ^= 0x5c;
83 }
84
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);
91}
92
93static int hmac_export(struct shash_desc *pdesc, void *out)
94{
95 struct shash_desc *desc = shash_desc_ctx(pdesc);
96
97 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
98
99 return crypto_shash_export(desc, out);
100}
101
102static int hmac_import(struct shash_desc *pdesc, const void *in)
103{
104 struct shash_desc *desc = shash_desc_ctx(pdesc);
105 struct hmac_ctx *ctx = hmac_ctx(pdesc->tfm);
106
107 desc->tfm = ctx->hash;
108 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
109
110 return crypto_shash_import(desc, in);
111}
112
113static int hmac_init(struct shash_desc *pdesc)
114{
115 return hmac_import(pdesc, crypto_shash_ctx_aligned(pdesc->tfm));
116}
117
118static int hmac_update(struct shash_desc *pdesc,
119 const u8 *data, unsigned int nbytes)
120{
121 struct shash_desc *desc = shash_desc_ctx(pdesc);
122
123 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
124
125 return crypto_shash_update(desc, data, nbytes);
126}
127
128static int hmac_final(struct shash_desc *pdesc, u8 *out)
129{
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);
135
136 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
137
138 return crypto_shash_final(desc, out) ?:
139 crypto_shash_import(desc, opad) ?:
140 crypto_shash_finup(desc, out, ds, out);
141}
142
143static int hmac_finup(struct shash_desc *pdesc, const u8 *data,
144 unsigned int nbytes, u8 *out)
145{
146
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);
152
153 desc->flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
154
155 return crypto_shash_finup(desc, data, nbytes, out) ?:
156 crypto_shash_import(desc, opad) ?:
157 crypto_shash_finup(desc, out, ds, out);
158}
159
160static int hmac_init_tfm(struct crypto_tfm *tfm)
161{
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);
167
168 hash = crypto_spawn_shash(spawn);
169 if (IS_ERR(hash))
170 return PTR_ERR(hash);
171
172 parent->descsize = sizeof(struct shash_desc) +
173 crypto_shash_descsize(hash);
174
175 ctx->hash = hash;
176 return 0;
177}
178
179static void hmac_exit_tfm(struct crypto_tfm *tfm)
180{
181 struct hmac_ctx *ctx = hmac_ctx(__crypto_shash_cast(tfm));
182 crypto_free_shash(ctx->hash);
183}
184
185static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
186{
187 struct shash_instance *inst;
188 struct crypto_alg *alg;
189 struct shash_alg *salg;
190 int err;
191 int ds;
192 int ss;
193
194 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
195 if (err)
196 return err;
197
198 salg = shash_attr_alg(tb[1], 0, 0);
199 if (IS_ERR(salg))
200 return PTR_ERR(salg);
201
202 err = -EINVAL;
203 ds = salg->digestsize;
204 ss = salg->statesize;
205 alg = &salg->base;
206 if (ds > alg->cra_blocksize ||
207 ss < alg->cra_blocksize)
208 goto out_put_alg;
209
210 inst = shash_alloc_instance("hmac", alg);
211 err = PTR_ERR(inst);
212 if (IS_ERR(inst))
213 goto out_put_alg;
214
215 err = crypto_init_shash_spawn(shash_instance_ctx(inst), salg,
216 shash_crypto_instance(inst));
217 if (err)
218 goto out_free_inst;
219
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;
223
224 ss = ALIGN(ss, alg->cra_alignmask + 1);
225 inst->alg.digestsize = ds;
226 inst->alg.statesize = ss;
227
228 inst->alg.base.cra_ctxsize = sizeof(struct hmac_ctx) +
229 ALIGN(ss * 2, crypto_tfm_ctx_alignment());
230
231 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;
238 inst->alg.export = hmac_export;
239 inst->alg.import = hmac_import;
240 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 }
247
248out_put_alg:
249 crypto_mod_put(alg);
250 return err;
251}
252
253static struct crypto_template hmac_tmpl = {
254 .name = "hmac",
255 .create = hmac_create,
256 .free = shash_free_instance,
257 .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");
275