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9#include <crypto/internal/cipher.h>
10#include <crypto/internal/hash.h>
11#include <linux/err.h>
12#include <linux/kernel.h>
13#include <linux/module.h>
14
15static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101,
16 0x02020202, 0x02020202, 0x02020202, 0x02020202,
17 0x03030303, 0x03030303, 0x03030303, 0x03030303};
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27
28struct xcbc_tfm_ctx {
29 struct crypto_cipher *child;
30 u8 ctx[];
31};
32
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42
43
44struct xcbc_desc_ctx {
45 unsigned int len;
46 u8 ctx[];
47};
48
49#define XCBC_BLOCKSIZE 16
50
51static int crypto_xcbc_digest_setkey(struct crypto_shash *parent,
52 const u8 *inkey, unsigned int keylen)
53{
54 unsigned long alignmask = crypto_shash_alignmask(parent);
55 struct xcbc_tfm_ctx *ctx = crypto_shash_ctx(parent);
56 u8 *consts = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
57 int err = 0;
58 u8 key1[XCBC_BLOCKSIZE];
59 int bs = sizeof(key1);
60
61 if ((err = crypto_cipher_setkey(ctx->child, inkey, keylen)))
62 return err;
63
64 crypto_cipher_encrypt_one(ctx->child, consts, (u8 *)ks + bs);
65 crypto_cipher_encrypt_one(ctx->child, consts + bs, (u8 *)ks + bs * 2);
66 crypto_cipher_encrypt_one(ctx->child, key1, (u8 *)ks);
67
68 return crypto_cipher_setkey(ctx->child, key1, bs);
69
70}
71
72static int crypto_xcbc_digest_init(struct shash_desc *pdesc)
73{
74 unsigned long alignmask = crypto_shash_alignmask(pdesc->tfm);
75 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
76 int bs = crypto_shash_blocksize(pdesc->tfm);
77 u8 *prev = PTR_ALIGN(&ctx->ctx[0], alignmask + 1) + bs;
78
79 ctx->len = 0;
80 memset(prev, 0, bs);
81
82 return 0;
83}
84
85static int crypto_xcbc_digest_update(struct shash_desc *pdesc, const u8 *p,
86 unsigned int len)
87{
88 struct crypto_shash *parent = pdesc->tfm;
89 unsigned long alignmask = crypto_shash_alignmask(parent);
90 struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
91 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
92 struct crypto_cipher *tfm = tctx->child;
93 int bs = crypto_shash_blocksize(parent);
94 u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
95 u8 *prev = odds + bs;
96
97
98 if ((ctx->len + len) <= bs) {
99 memcpy(odds + ctx->len, p, len);
100 ctx->len += len;
101 return 0;
102 }
103
104
105 memcpy(odds + ctx->len, p, bs - ctx->len);
106 len -= bs - ctx->len;
107 p += bs - ctx->len;
108
109 crypto_xor(prev, odds, bs);
110 crypto_cipher_encrypt_one(tfm, prev, prev);
111
112
113 ctx->len = 0;
114
115
116 while (len > bs) {
117 crypto_xor(prev, p, bs);
118 crypto_cipher_encrypt_one(tfm, prev, prev);
119 p += bs;
120 len -= bs;
121 }
122
123
124 if (len) {
125 memcpy(odds, p, len);
126 ctx->len = len;
127 }
128
129 return 0;
130}
131
132static int crypto_xcbc_digest_final(struct shash_desc *pdesc, u8 *out)
133{
134 struct crypto_shash *parent = pdesc->tfm;
135 unsigned long alignmask = crypto_shash_alignmask(parent);
136 struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
137 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
138 struct crypto_cipher *tfm = tctx->child;
139 int bs = crypto_shash_blocksize(parent);
140 u8 *consts = PTR_ALIGN(&tctx->ctx[0], alignmask + 1);
141 u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
142 u8 *prev = odds + bs;
143 unsigned int offset = 0;
144
145 if (ctx->len != bs) {
146 unsigned int rlen;
147 u8 *p = odds + ctx->len;
148
149 *p = 0x80;
150 p++;
151
152 rlen = bs - ctx->len -1;
153 if (rlen)
154 memset(p, 0, rlen);
155
156 offset += bs;
157 }
158
159 crypto_xor(prev, odds, bs);
160 crypto_xor(prev, consts + offset, bs);
161
162 crypto_cipher_encrypt_one(tfm, out, prev);
163
164 return 0;
165}
166
167static int xcbc_init_tfm(struct crypto_tfm *tfm)
168{
169 struct crypto_cipher *cipher;
170 struct crypto_instance *inst = (void *)tfm->__crt_alg;
171 struct crypto_cipher_spawn *spawn = crypto_instance_ctx(inst);
172 struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
173
174 cipher = crypto_spawn_cipher(spawn);
175 if (IS_ERR(cipher))
176 return PTR_ERR(cipher);
177
178 ctx->child = cipher;
179
180 return 0;
181};
182
183static void xcbc_exit_tfm(struct crypto_tfm *tfm)
184{
185 struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
186 crypto_free_cipher(ctx->child);
187}
188
189static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
190{
191 struct shash_instance *inst;
192 struct crypto_cipher_spawn *spawn;
193 struct crypto_alg *alg;
194 unsigned long alignmask;
195 u32 mask;
196 int err;
197
198 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH, &mask);
199 if (err)
200 return err;
201
202 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
203 if (!inst)
204 return -ENOMEM;
205 spawn = shash_instance_ctx(inst);
206
207 err = crypto_grab_cipher(spawn, shash_crypto_instance(inst),
208 crypto_attr_alg_name(tb[1]), 0, mask);
209 if (err)
210 goto err_free_inst;
211 alg = crypto_spawn_cipher_alg(spawn);
212
213 err = -EINVAL;
214 if (alg->cra_blocksize != XCBC_BLOCKSIZE)
215 goto err_free_inst;
216
217 err = crypto_inst_setname(shash_crypto_instance(inst), tmpl->name, alg);
218 if (err)
219 goto err_free_inst;
220
221 alignmask = alg->cra_alignmask | 3;
222 inst->alg.base.cra_alignmask = alignmask;
223 inst->alg.base.cra_priority = alg->cra_priority;
224 inst->alg.base.cra_blocksize = alg->cra_blocksize;
225
226 inst->alg.digestsize = alg->cra_blocksize;
227 inst->alg.descsize = ALIGN(sizeof(struct xcbc_desc_ctx),
228 crypto_tfm_ctx_alignment()) +
229 (alignmask &
230 ~(crypto_tfm_ctx_alignment() - 1)) +
231 alg->cra_blocksize * 2;
232
233 inst->alg.base.cra_ctxsize = ALIGN(sizeof(struct xcbc_tfm_ctx),
234 alignmask + 1) +
235 alg->cra_blocksize * 2;
236 inst->alg.base.cra_init = xcbc_init_tfm;
237 inst->alg.base.cra_exit = xcbc_exit_tfm;
238
239 inst->alg.init = crypto_xcbc_digest_init;
240 inst->alg.update = crypto_xcbc_digest_update;
241 inst->alg.final = crypto_xcbc_digest_final;
242 inst->alg.setkey = crypto_xcbc_digest_setkey;
243
244 inst->free = shash_free_singlespawn_instance;
245
246 err = shash_register_instance(tmpl, inst);
247 if (err) {
248err_free_inst:
249 shash_free_singlespawn_instance(inst);
250 }
251 return err;
252}
253
254static struct crypto_template crypto_xcbc_tmpl = {
255 .name = "xcbc",
256 .create = xcbc_create,
257 .module = THIS_MODULE,
258};
259
260static int __init crypto_xcbc_module_init(void)
261{
262 return crypto_register_template(&crypto_xcbc_tmpl);
263}
264
265static void __exit crypto_xcbc_module_exit(void)
266{
267 crypto_unregister_template(&crypto_xcbc_tmpl);
268}
269
270subsys_initcall(crypto_xcbc_module_init);
271module_exit(crypto_xcbc_module_exit);
272
273MODULE_LICENSE("GPL");
274MODULE_DESCRIPTION("XCBC keyed hash algorithm");
275MODULE_ALIAS_CRYPTO("xcbc");
276MODULE_IMPORT_NS(CRYPTO_INTERNAL);
277
