crypto: hash - Export shash through hash
[linux-2.6.git] / crypto / ahash.c
1 /*
2  * Asynchronous Cryptographic Hash operations.
3  *
4  * This is the asynchronous version of hash.c with notification of
5  * completion via a callback.
6  *
7  * Copyright (c) 2008 Loc Ho <lho@amcc.com>
8  *
9  * This program is free software; you can redistribute it and/or modify it
10  * under the terms of the GNU General Public License as published by the Free
11  * Software Foundation; either version 2 of the License, or (at your option)
12  * any later version.
13  *
14  */
15
16 #include <crypto/internal/hash.h>
17 #include <crypto/scatterwalk.h>
18 #include <linux/err.h>
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/sched.h>
22 #include <linux/slab.h>
23 #include <linux/seq_file.h>
24
25 #include "internal.h"
26
27 static int hash_walk_next(struct crypto_hash_walk *walk)
28 {
29         unsigned int alignmask = walk->alignmask;
30         unsigned int offset = walk->offset;
31         unsigned int nbytes = min(walk->entrylen,
32                                   ((unsigned int)(PAGE_SIZE)) - offset);
33
34         walk->data = crypto_kmap(walk->pg, 0);
35         walk->data += offset;
36
37         if (offset & alignmask)
38                 nbytes = alignmask + 1 - (offset & alignmask);
39
40         walk->entrylen -= nbytes;
41         return nbytes;
42 }
43
44 static int hash_walk_new_entry(struct crypto_hash_walk *walk)
45 {
46         struct scatterlist *sg;
47
48         sg = walk->sg;
49         walk->pg = sg_page(sg);
50         walk->offset = sg->offset;
51         walk->entrylen = sg->length;
52
53         if (walk->entrylen > walk->total)
54                 walk->entrylen = walk->total;
55         walk->total -= walk->entrylen;
56
57         return hash_walk_next(walk);
58 }
59
60 int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
61 {
62         unsigned int alignmask = walk->alignmask;
63         unsigned int nbytes = walk->entrylen;
64
65         walk->data -= walk->offset;
66
67         if (nbytes && walk->offset & alignmask && !err) {
68                 walk->offset += alignmask - 1;
69                 walk->offset = ALIGN(walk->offset, alignmask + 1);
70                 walk->data += walk->offset;
71
72                 nbytes = min(nbytes,
73                              ((unsigned int)(PAGE_SIZE)) - walk->offset);
74                 walk->entrylen -= nbytes;
75
76                 return nbytes;
77         }
78
79         crypto_kunmap(walk->data, 0);
80         crypto_yield(walk->flags);
81
82         if (err)
83                 return err;
84
85         walk->offset = 0;
86
87         if (nbytes)
88                 return hash_walk_next(walk);
89
90         if (!walk->total)
91                 return 0;
92
93         walk->sg = scatterwalk_sg_next(walk->sg);
94
95         return hash_walk_new_entry(walk);
96 }
97 EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
98
99 int crypto_hash_walk_first(struct ahash_request *req,
100                            struct crypto_hash_walk *walk)
101 {
102         walk->total = req->nbytes;
103
104         if (!walk->total)
105                 return 0;
106
107         walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
108         walk->sg = req->src;
109         walk->flags = req->base.flags;
110
111         return hash_walk_new_entry(walk);
112 }
113 EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
114
115 int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
116                                   struct crypto_hash_walk *walk,
117                                   struct scatterlist *sg, unsigned int len)
118 {
119         walk->total = len;
120
121         if (!walk->total)
122                 return 0;
123
124         walk->alignmask = crypto_hash_alignmask(hdesc->tfm);
125         walk->sg = sg;
126         walk->flags = hdesc->flags;
127
128         return hash_walk_new_entry(walk);
129 }
130
131 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
132                                 unsigned int keylen)
133 {
134         struct ahash_alg *ahash = crypto_ahash_alg(tfm);
135         unsigned long alignmask = crypto_ahash_alignmask(tfm);
136         int ret;
137         u8 *buffer, *alignbuffer;
138         unsigned long absize;
139
140         absize = keylen + alignmask;
141         buffer = kmalloc(absize, GFP_ATOMIC);
142         if (!buffer)
143                 return -ENOMEM;
144
145         alignbuffer = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
146         memcpy(alignbuffer, key, keylen);
147         ret = ahash->setkey(tfm, alignbuffer, keylen);
148         memset(alignbuffer, 0, keylen);
149         kfree(buffer);
150         return ret;
151 }
152
153 static int ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
154                         unsigned int keylen)
155 {
156         struct ahash_alg *ahash = crypto_ahash_alg(tfm);
157         unsigned long alignmask = crypto_ahash_alignmask(tfm);
158
159         if ((unsigned long)key & alignmask)
160                 return ahash_setkey_unaligned(tfm, key, keylen);
161
162         return ahash->setkey(tfm, key, keylen);
163 }
164
165 int crypto_ahash_import(struct ahash_request *req, const u8 *in)
166 {
167         struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
168         struct ahash_alg *alg = crypto_ahash_alg(tfm);
169
170         memcpy(ahash_request_ctx(req), in, crypto_ahash_reqsize(tfm));
171
172         if (alg->reinit)
173                 alg->reinit(req);
174
175         return 0;
176 }
177 EXPORT_SYMBOL_GPL(crypto_ahash_import);
178
179 static unsigned int crypto_ahash_ctxsize(struct crypto_alg *alg, u32 type,
180                                         u32 mask)
181 {
182         return alg->cra_ctxsize;
183 }
184
185 static int crypto_init_ahash_ops(struct crypto_tfm *tfm, u32 type, u32 mask)
186 {
187         struct ahash_alg *alg = &tfm->__crt_alg->cra_ahash;
188         struct ahash_tfm *crt   = &tfm->crt_ahash;
189
190         if (alg->digestsize > PAGE_SIZE / 8)
191                 return -EINVAL;
192
193         crt->init = alg->init;
194         crt->update = alg->update;
195         crt->final  = alg->final;
196         crt->digest = alg->digest;
197         crt->setkey = ahash_setkey;
198         crt->digestsize = alg->digestsize;
199
200         return 0;
201 }
202
203 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
204         __attribute__ ((unused));
205 static void crypto_ahash_show(struct seq_file *m, struct crypto_alg *alg)
206 {
207         seq_printf(m, "type         : ahash\n");
208         seq_printf(m, "async        : %s\n", alg->cra_flags & CRYPTO_ALG_ASYNC ?
209                                              "yes" : "no");
210         seq_printf(m, "blocksize    : %u\n", alg->cra_blocksize);
211         seq_printf(m, "digestsize   : %u\n", alg->cra_hash.digestsize);
212 }
213
214 const struct crypto_type crypto_ahash_type = {
215         .ctxsize = crypto_ahash_ctxsize,
216         .init = crypto_init_ahash_ops,
217 #ifdef CONFIG_PROC_FS
218         .show = crypto_ahash_show,
219 #endif
220 };
221 EXPORT_SYMBOL_GPL(crypto_ahash_type);
222
223 MODULE_LICENSE("GPL");
224 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");