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22#include <crypto/internal/hash.h>
23#include <linux/err.h>
24#include <linux/kernel.h>
25
26static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101,
27 0x02020202, 0x02020202, 0x02020202, 0x02020202,
28 0x03030303, 0x03030303, 0x03030303, 0x03030303};
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38
39struct xcbc_tfm_ctx {
40 struct crypto_cipher *child;
41 u8 ctx[];
42};
43
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53
54
55struct xcbc_desc_ctx {
56 unsigned int len;
57 u8 ctx[];
58};
59
60static int crypto_xcbc_digest_setkey(struct crypto_shash *parent,
61 const u8 *inkey, unsigned int keylen)
62{
63 unsigned long alignmask = crypto_shash_alignmask(parent);
64 struct xcbc_tfm_ctx *ctx = crypto_shash_ctx(parent);
65 int bs = crypto_shash_blocksize(parent);
66 u8 *consts = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
67 int err = 0;
68 u8 key1[bs];
69
70 if ((err = crypto_cipher_setkey(ctx->child, inkey, keylen)))
71 return err;
72
73 crypto_cipher_encrypt_one(ctx->child, consts, (u8 *)ks + bs);
74 crypto_cipher_encrypt_one(ctx->child, consts + bs, (u8 *)ks + bs * 2);
75 crypto_cipher_encrypt_one(ctx->child, key1, (u8 *)ks);
76
77 return crypto_cipher_setkey(ctx->child, key1, bs);
78
79}
80
81static int crypto_xcbc_digest_init(struct shash_desc *pdesc)
82{
83 unsigned long alignmask = crypto_shash_alignmask(pdesc->tfm);
84 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
85 int bs = crypto_shash_blocksize(pdesc->tfm);
86 u8 *prev = PTR_ALIGN(&ctx->ctx[0], alignmask + 1) + bs;
87
88 ctx->len = 0;
89 memset(prev, 0, bs);
90
91 return 0;
92}
93
94static int crypto_xcbc_digest_update(struct shash_desc *pdesc, const u8 *p,
95 unsigned int len)
96{
97 struct crypto_shash *parent = pdesc->tfm;
98 unsigned long alignmask = crypto_shash_alignmask(parent);
99 struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
100 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
101 struct crypto_cipher *tfm = tctx->child;
102 int bs = crypto_shash_blocksize(parent);
103 u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
104 u8 *prev = odds + bs;
105
106
107 if ((ctx->len + len) <= bs) {
108 memcpy(odds + ctx->len, p, len);
109 ctx->len += len;
110 return 0;
111 }
112
113
114 memcpy(odds + ctx->len, p, bs - ctx->len);
115 len -= bs - ctx->len;
116 p += bs - ctx->len;
117
118 crypto_xor(prev, odds, bs);
119 crypto_cipher_encrypt_one(tfm, prev, prev);
120
121
122 ctx->len = 0;
123
124
125 while (len > bs) {
126 crypto_xor(prev, p, bs);
127 crypto_cipher_encrypt_one(tfm, prev, prev);
128 p += bs;
129 len -= bs;
130 }
131
132
133 if (len) {
134 memcpy(odds, p, len);
135 ctx->len = len;
136 }
137
138 return 0;
139}
140
141static int crypto_xcbc_digest_final(struct shash_desc *pdesc, u8 *out)
142{
143 struct crypto_shash *parent = pdesc->tfm;
144 unsigned long alignmask = crypto_shash_alignmask(parent);
145 struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
146 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
147 struct crypto_cipher *tfm = tctx->child;
148 int bs = crypto_shash_blocksize(parent);
149 u8 *consts = PTR_ALIGN(&tctx->ctx[0], alignmask + 1);
150 u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
151 u8 *prev = odds + bs;
152 unsigned int offset = 0;
153
154 if (ctx->len != bs) {
155 unsigned int rlen;
156 u8 *p = odds + ctx->len;
157
158 *p = 0x80;
159 p++;
160
161 rlen = bs - ctx->len -1;
162 if (rlen)
163 memset(p, 0, rlen);
164
165 offset += bs;
166 }
167
168 crypto_xor(prev, odds, bs);
169 crypto_xor(prev, consts + offset, bs);
170
171 crypto_cipher_encrypt_one(tfm, out, prev);
172
173 return 0;
174}
175
176static int xcbc_init_tfm(struct crypto_tfm *tfm)
177{
178 struct crypto_cipher *cipher;
179 struct crypto_instance *inst = (void *)tfm->__crt_alg;
180 struct crypto_spawn *spawn = crypto_instance_ctx(inst);
181 struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
182
183 cipher = crypto_spawn_cipher(spawn);
184 if (IS_ERR(cipher))
185 return PTR_ERR(cipher);
186
187 ctx->child = cipher;
188
189 return 0;
190};
191
192static void xcbc_exit_tfm(struct crypto_tfm *tfm)
193{
194 struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
195 crypto_free_cipher(ctx->child);
196}
197
198static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
199{
200 struct shash_instance *inst;
201 struct crypto_alg *alg;
202 unsigned long alignmask;
203 int err;
204
205 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
206 if (err)
207 return err;
208
209 alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
210 CRYPTO_ALG_TYPE_MASK);
211 if (IS_ERR(alg))
212 return PTR_ERR(alg);
213
214 switch(alg->cra_blocksize) {
215 case 16:
216 break;
217 default:
218 goto out_put_alg;
219 }
220
221 inst = shash_alloc_instance("xcbc", alg);
222 err = PTR_ERR(inst);
223 if (IS_ERR(inst))
224 goto out_put_alg;
225
226 err = crypto_init_spawn(shash_instance_ctx(inst), alg,
227 shash_crypto_instance(inst),
228 CRYPTO_ALG_TYPE_MASK);
229 if (err)
230 goto out_free_inst;
231
232 alignmask = alg->cra_alignmask | 3;
233 inst->alg.base.cra_alignmask = alignmask;
234 inst->alg.base.cra_priority = alg->cra_priority;
235 inst->alg.base.cra_blocksize = alg->cra_blocksize;
236
237 inst->alg.digestsize = alg->cra_blocksize;
238 inst->alg.descsize = ALIGN(sizeof(struct xcbc_desc_ctx),
239 crypto_tfm_ctx_alignment()) +
240 (alignmask &
241 ~(crypto_tfm_ctx_alignment() - 1)) +
242 alg->cra_blocksize * 2;
243
244 inst->alg.base.cra_ctxsize = ALIGN(sizeof(struct xcbc_tfm_ctx),
245 alignmask + 1) +
246 alg->cra_blocksize * 2;
247 inst->alg.base.cra_init = xcbc_init_tfm;
248 inst->alg.base.cra_exit = xcbc_exit_tfm;
249
250 inst->alg.init = crypto_xcbc_digest_init;
251 inst->alg.update = crypto_xcbc_digest_update;
252 inst->alg.final = crypto_xcbc_digest_final;
253 inst->alg.setkey = crypto_xcbc_digest_setkey;
254
255 err = shash_register_instance(tmpl, inst);
256 if (err) {
257out_free_inst:
258 shash_free_instance(shash_crypto_instance(inst));
259 }
260
261out_put_alg:
262 crypto_mod_put(alg);
263 return err;
264}
265
266static struct crypto_template crypto_xcbc_tmpl = {
267 .name = "xcbc",
268 .create = xcbc_create,
269 .free = shash_free_instance,
270 .module = THIS_MODULE,
271};
272
273static int __init crypto_xcbc_module_init(void)
274{
275 return crypto_register_template(&crypto_xcbc_tmpl);
276}
277
278static void __exit crypto_xcbc_module_exit(void)
279{
280 crypto_unregister_template(&crypto_xcbc_tmpl);
281}
282
283module_init(crypto_xcbc_module_init);
284module_exit(crypto_xcbc_module_exit);
285
286MODULE_LICENSE("GPL");
287MODULE_DESCRIPTION("XCBC keyed hash algorithm");
288
