crypto: crc32c - Add ahash implementation
[linux-2.6.git] / crypto / digest.c
1 /*
2  * Cryptographic API.
3  *
4  * Digest operations.
5  *
6  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms of the GNU General Public License as published by the Free
10  * Software Foundation; either version 2 of the License, or (at your option) 
11  * any later version.
12  *
13  */
14
15 #include <crypto/scatterwalk.h>
16 #include <linux/mm.h>
17 #include <linux/errno.h>
18 #include <linux/hardirq.h>
19 #include <linux/highmem.h>
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/scatterlist.h>
23
24 #include "internal.h"
25
26 static int init(struct hash_desc *desc)
27 {
28         struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
29
30         tfm->__crt_alg->cra_digest.dia_init(tfm);
31         return 0;
32 }
33
34 static int update2(struct hash_desc *desc,
35                    struct scatterlist *sg, unsigned int nbytes)
36 {
37         struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
38         unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
39
40         if (!nbytes)
41                 return 0;
42
43         for (;;) {
44                 struct page *pg = sg_page(sg);
45                 unsigned int offset = sg->offset;
46                 unsigned int l = sg->length;
47
48                 if (unlikely(l > nbytes))
49                         l = nbytes;
50                 nbytes -= l;
51
52                 do {
53                         unsigned int bytes_from_page = min(l, ((unsigned int)
54                                                            (PAGE_SIZE)) - 
55                                                            offset);
56                         char *src = crypto_kmap(pg, 0);
57                         char *p = src + offset;
58
59                         if (unlikely(offset & alignmask)) {
60                                 unsigned int bytes =
61                                         alignmask + 1 - (offset & alignmask);
62                                 bytes = min(bytes, bytes_from_page);
63                                 tfm->__crt_alg->cra_digest.dia_update(tfm, p,
64                                                                       bytes);
65                                 p += bytes;
66                                 bytes_from_page -= bytes;
67                                 l -= bytes;
68                         }
69                         tfm->__crt_alg->cra_digest.dia_update(tfm, p,
70                                                               bytes_from_page);
71                         crypto_kunmap(src, 0);
72                         crypto_yield(desc->flags);
73                         offset = 0;
74                         pg++;
75                         l -= bytes_from_page;
76                 } while (l > 0);
77
78                 if (!nbytes)
79                         break;
80                 sg = scatterwalk_sg_next(sg);
81         }
82
83         return 0;
84 }
85
86 static int update(struct hash_desc *desc,
87                   struct scatterlist *sg, unsigned int nbytes)
88 {
89         if (WARN_ON_ONCE(in_irq()))
90                 return -EDEADLK;
91         return update2(desc, sg, nbytes);
92 }
93
94 static int final(struct hash_desc *desc, u8 *out)
95 {
96         struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
97         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
98         struct digest_alg *digest = &tfm->__crt_alg->cra_digest;
99
100         if (unlikely((unsigned long)out & alignmask)) {
101                 unsigned long align = alignmask + 1;
102                 unsigned long addr = (unsigned long)crypto_tfm_ctx(tfm);
103                 u8 *dst = (u8 *)ALIGN(addr, align) +
104                           ALIGN(tfm->__crt_alg->cra_ctxsize, align);
105
106                 digest->dia_final(tfm, dst);
107                 memcpy(out, dst, digest->dia_digestsize);
108         } else
109                 digest->dia_final(tfm, out);
110
111         return 0;
112 }
113
114 static int nosetkey(struct crypto_hash *tfm, const u8 *key, unsigned int keylen)
115 {
116         crypto_hash_clear_flags(tfm, CRYPTO_TFM_RES_MASK);
117         return -ENOSYS;
118 }
119
120 static int setkey(struct crypto_hash *hash, const u8 *key, unsigned int keylen)
121 {
122         struct crypto_tfm *tfm = crypto_hash_tfm(hash);
123
124         crypto_hash_clear_flags(hash, CRYPTO_TFM_RES_MASK);
125         return tfm->__crt_alg->cra_digest.dia_setkey(tfm, key, keylen);
126 }
127
128 static int digest(struct hash_desc *desc,
129                   struct scatterlist *sg, unsigned int nbytes, u8 *out)
130 {
131         if (WARN_ON_ONCE(in_irq()))
132                 return -EDEADLK;
133
134         init(desc);
135         update2(desc, sg, nbytes);
136         return final(desc, out);
137 }
138
139 int crypto_init_digest_ops(struct crypto_tfm *tfm)
140 {
141         struct hash_tfm *ops = &tfm->crt_hash;
142         struct digest_alg *dalg = &tfm->__crt_alg->cra_digest;
143
144         if (dalg->dia_digestsize > PAGE_SIZE / 8)
145                 return -EINVAL;
146         
147         ops->init       = init;
148         ops->update     = update;
149         ops->final      = final;
150         ops->digest     = digest;
151         ops->setkey     = dalg->dia_setkey ? setkey : nosetkey;
152         ops->digestsize = dalg->dia_digestsize;
153         
154         return 0;
155 }
156
157 void crypto_exit_digest_ops(struct crypto_tfm *tfm)
158 {
159 }
160
161 static int digest_async_nosetkey(struct crypto_ahash *tfm_async, const u8 *key,
162                         unsigned int keylen)
163 {
164         crypto_ahash_clear_flags(tfm_async, CRYPTO_TFM_RES_MASK);
165         return -ENOSYS;
166 }
167
168 static int digest_async_setkey(struct crypto_ahash *tfm_async, const u8 *key,
169                         unsigned int keylen)
170 {
171         struct crypto_tfm    *tfm        = crypto_ahash_tfm(tfm_async);
172         struct digest_alg    *dalg       = &tfm->__crt_alg->cra_digest;
173
174         crypto_ahash_clear_flags(tfm_async, CRYPTO_TFM_RES_MASK);
175         return dalg->dia_setkey(tfm, key, keylen);
176 }
177
178 static int digest_async_init(struct ahash_request *req)
179 {
180         struct crypto_tfm *tfm  = req->base.tfm;
181         struct digest_alg *dalg = &tfm->__crt_alg->cra_digest;
182
183         dalg->dia_init(tfm);
184         return 0;
185 }
186
187 static int digest_async_update(struct ahash_request *req)
188 {
189         struct crypto_tfm *tfm = req->base.tfm;
190         struct hash_desc  desc = {
191                 .tfm   = __crypto_hash_cast(tfm),
192                 .flags = req->base.flags,
193         };
194
195         update(&desc, req->src, req->nbytes);
196         return 0;
197 }
198
199 static int digest_async_final(struct ahash_request *req)
200 {
201         struct crypto_tfm *tfm  = req->base.tfm;
202         struct hash_desc  desc = {
203                 .tfm   = __crypto_hash_cast(tfm),
204                 .flags = req->base.flags,
205         };
206
207         final(&desc, req->result);
208         return 0;
209 }
210
211 static int digest_async_digest(struct ahash_request *req)
212 {
213         struct crypto_tfm *tfm  = req->base.tfm;
214         struct hash_desc  desc = {
215                 .tfm   = __crypto_hash_cast(tfm),
216                 .flags = req->base.flags,
217         };
218
219         return digest(&desc, req->src, req->nbytes, req->result);
220 }
221
222 int crypto_init_digest_ops_async(struct crypto_tfm *tfm)
223 {
224         struct ahash_tfm  *crt  = &tfm->crt_ahash;
225         struct digest_alg *dalg = &tfm->__crt_alg->cra_digest;
226
227         if (dalg->dia_digestsize > crypto_tfm_alg_blocksize(tfm))
228                 return -EINVAL;
229
230         crt->init       = digest_async_init;
231         crt->update     = digest_async_update;
232         crt->final      = digest_async_final;
233         crt->digest     = digest_async_digest;
234         crt->setkey     = dalg->dia_setkey ? digest_async_setkey :
235                                                 digest_async_nosetkey;
236         crt->digestsize = dalg->dia_digestsize;
237
238         return 0;
239 }