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22#include <crypto/internal/hash.h>
23#include <linux/err.h>
24#include <linux/kernel.h>
25#include <linux/module.h>
26
27static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101,
28 0x02020202, 0x02020202, 0x02020202, 0x02020202,
29 0x03030303, 0x03030303, 0x03030303, 0x03030303};
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39
40struct xcbc_tfm_ctx {
41 struct crypto_cipher *child;
42 u8 ctx[];
43};
44
45
46
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48
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54
55
56struct xcbc_desc_ctx {
57 unsigned int len;
58 u8 ctx[];
59};
60
61static int crypto_xcbc_digest_setkey(struct crypto_shash *parent,
62 const u8 *inkey, unsigned int keylen)
63{
64 unsigned long alignmask = crypto_shash_alignmask(parent);
65 struct xcbc_tfm_ctx *ctx = crypto_shash_ctx(parent);
66 int bs = crypto_shash_blocksize(parent);
67 u8 *consts = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
68 int err = 0;
69 u8 key1[bs];
70
71 if ((err = crypto_cipher_setkey(ctx->child, inkey, keylen)))
72 return err;
73
74 crypto_cipher_encrypt_one(ctx->child, consts, (u8 *)ks + bs);
75 crypto_cipher_encrypt_one(ctx->child, consts + bs, (u8 *)ks + bs * 2);
76 crypto_cipher_encrypt_one(ctx->child, key1, (u8 *)ks);
77
78 return crypto_cipher_setkey(ctx->child, key1, bs);
79
80}
81
82static int crypto_xcbc_digest_init(struct shash_desc *pdesc)
83{
84 unsigned long alignmask = crypto_shash_alignmask(pdesc->tfm);
85 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
86 int bs = crypto_shash_blocksize(pdesc->tfm);
87 u8 *prev = PTR_ALIGN(&ctx->ctx[0], alignmask + 1) + bs;
88
89 ctx->len = 0;
90 memset(prev, 0, bs);
91
92 return 0;
93}
94
95static int crypto_xcbc_digest_update(struct shash_desc *pdesc, const u8 *p,
96 unsigned int len)
97{
98 struct crypto_shash *parent = pdesc->tfm;
99 unsigned long alignmask = crypto_shash_alignmask(parent);
100 struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
101 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
102 struct crypto_cipher *tfm = tctx->child;
103 int bs = crypto_shash_blocksize(parent);
104 u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
105 u8 *prev = odds + bs;
106
107
108 if ((ctx->len + len) <= bs) {
109 memcpy(odds + ctx->len, p, len);
110 ctx->len += len;
111 return 0;
112 }
113
114
115 memcpy(odds + ctx->len, p, bs - ctx->len);
116 len -= bs - ctx->len;
117 p += bs - ctx->len;
118
119 crypto_xor(prev, odds, bs);
120 crypto_cipher_encrypt_one(tfm, prev, prev);
121
122
123 ctx->len = 0;
124
125
126 while (len > bs) {
127 crypto_xor(prev, p, bs);
128 crypto_cipher_encrypt_one(tfm, prev, prev);
129 p += bs;
130 len -= bs;
131 }
132
133
134 if (len) {
135 memcpy(odds, p, len);
136 ctx->len = len;
137 }
138
139 return 0;
140}
141
142static int crypto_xcbc_digest_final(struct shash_desc *pdesc, u8 *out)
143{
144 struct crypto_shash *parent = pdesc->tfm;
145 unsigned long alignmask = crypto_shash_alignmask(parent);
146 struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
147 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
148 struct crypto_cipher *tfm = tctx->child;
149 int bs = crypto_shash_blocksize(parent);
150 u8 *consts = PTR_ALIGN(&tctx->ctx[0], alignmask + 1);
151 u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
152 u8 *prev = odds + bs;
153 unsigned int offset = 0;
154
155 if (ctx->len != bs) {
156 unsigned int rlen;
157 u8 *p = odds + ctx->len;
158
159 *p = 0x80;
160 p++;
161
162 rlen = bs - ctx->len -1;
163 if (rlen)
164 memset(p, 0, rlen);
165
166 offset += bs;
167 }
168
169 crypto_xor(prev, odds, bs);
170 crypto_xor(prev, consts + offset, bs);
171
172 crypto_cipher_encrypt_one(tfm, out, prev);
173
174 return 0;
175}
176
177static int xcbc_init_tfm(struct crypto_tfm *tfm)
178{
179 struct crypto_cipher *cipher;
180 struct crypto_instance *inst = (void *)tfm->__crt_alg;
181 struct crypto_spawn *spawn = crypto_instance_ctx(inst);
182 struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
183
184 cipher = crypto_spawn_cipher(spawn);
185 if (IS_ERR(cipher))
186 return PTR_ERR(cipher);
187
188 ctx->child = cipher;
189
190 return 0;
191};
192
193static void xcbc_exit_tfm(struct crypto_tfm *tfm)
194{
195 struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
196 crypto_free_cipher(ctx->child);
197}
198
199static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
200{
201 struct shash_instance *inst;
202 struct crypto_alg *alg;
203 unsigned long alignmask;
204 int err;
205
206 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
207 if (err)
208 return err;
209
210 alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
211 CRYPTO_ALG_TYPE_MASK);
212 if (IS_ERR(alg))
213 return PTR_ERR(alg);
214
215 switch(alg->cra_blocksize) {
216 case 16:
217 break;
218 default:
219 goto out_put_alg;
220 }
221
222 inst = shash_alloc_instance("xcbc", alg);
223 err = PTR_ERR(inst);
224 if (IS_ERR(inst))
225 goto out_put_alg;
226
227 err = crypto_init_spawn(shash_instance_ctx(inst), alg,
228 shash_crypto_instance(inst),
229 CRYPTO_ALG_TYPE_MASK);
230 if (err)
231 goto out_free_inst;
232
233 alignmask = alg->cra_alignmask | 3;
234 inst->alg.base.cra_alignmask = alignmask;
235 inst->alg.base.cra_priority = alg->cra_priority;
236 inst->alg.base.cra_blocksize = alg->cra_blocksize;
237
238 inst->alg.digestsize = alg->cra_blocksize;
239 inst->alg.descsize = ALIGN(sizeof(struct xcbc_desc_ctx),
240 crypto_tfm_ctx_alignment()) +
241 (alignmask &
242 ~(crypto_tfm_ctx_alignment() - 1)) +
243 alg->cra_blocksize * 2;
244
245 inst->alg.base.cra_ctxsize = ALIGN(sizeof(struct xcbc_tfm_ctx),
246 alignmask + 1) +
247 alg->cra_blocksize * 2;
248 inst->alg.base.cra_init = xcbc_init_tfm;
249 inst->alg.base.cra_exit = xcbc_exit_tfm;
250
251 inst->alg.init = crypto_xcbc_digest_init;
252 inst->alg.update = crypto_xcbc_digest_update;
253 inst->alg.final = crypto_xcbc_digest_final;
254 inst->alg.setkey = crypto_xcbc_digest_setkey;
255
256 err = shash_register_instance(tmpl, inst);
257 if (err) {
258out_free_inst:
259 shash_free_instance(shash_crypto_instance(inst));
260 }
261
262out_put_alg:
263 crypto_mod_put(alg);
264 return err;
265}
266
267static struct crypto_template crypto_xcbc_tmpl = {
268 .name = "xcbc",
269 .create = xcbc_create,
270 .free = shash_free_instance,
271 .module = THIS_MODULE,
272};
273
274static int __init crypto_xcbc_module_init(void)
275{
276 return crypto_register_template(&crypto_xcbc_tmpl);
277}
278
279static void __exit crypto_xcbc_module_exit(void)
280{
281 crypto_unregister_template(&crypto_xcbc_tmpl);
282}
283
284module_init(crypto_xcbc_module_init);
285module_exit(crypto_xcbc_module_exit);
286
287MODULE_LICENSE("GPL");
288MODULE_DESCRIPTION("XCBC keyed hash algorithm");
289MODULE_ALIAS_CRYPTO("xcbc");
290
