8f4593268ce0bf5c5ef2e9e47d8ab72789adb842
[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 <linux/mm.h>
16 #include <linux/errno.h>
17 #include <linux/highmem.h>
18 #include <linux/module.h>
19 #include <linux/scatterlist.h>
20
21 #include "internal.h"
22 #include "scatterwalk.h"
23
24 static int init(struct hash_desc *desc)
25 {
26         struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
27
28         tfm->__crt_alg->cra_digest.dia_init(tfm);
29         return 0;
30 }
31
32 static int update(struct hash_desc *desc,
33                   struct scatterlist *sg, unsigned int nbytes)
34 {
35         struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
36         unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
37
38         if (!nbytes)
39                 return 0;
40
41         for (;;) {
42                 struct page *pg = sg->page;
43                 unsigned int offset = sg->offset;
44                 unsigned int l = sg->length;
45
46                 if (unlikely(l > nbytes))
47                         l = nbytes;
48                 nbytes -= l;
49
50                 do {
51                         unsigned int bytes_from_page = min(l, ((unsigned int)
52                                                            (PAGE_SIZE)) - 
53                                                            offset);
54                         char *src = crypto_kmap(pg, 0);
55                         char *p = src + offset;
56
57                         if (unlikely(offset & alignmask)) {
58                                 unsigned int bytes =
59                                         alignmask + 1 - (offset & alignmask);
60                                 bytes = min(bytes, bytes_from_page);
61                                 tfm->__crt_alg->cra_digest.dia_update(tfm, p,
62                                                                       bytes);
63                                 p += bytes;
64                                 bytes_from_page -= bytes;
65                                 l -= bytes;
66                         }
67                         tfm->__crt_alg->cra_digest.dia_update(tfm, p,
68                                                               bytes_from_page);
69                         crypto_kunmap(src, 0);
70                         crypto_yield(desc->flags);
71                         offset = 0;
72                         pg++;
73                         l -= bytes_from_page;
74                 } while (l > 0);
75
76                 if (!nbytes)
77                         break;
78                 sg = sg_next(sg);
79         }
80
81         return 0;
82 }
83
84 static int final(struct hash_desc *desc, u8 *out)
85 {
86         struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
87         unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
88         struct digest_alg *digest = &tfm->__crt_alg->cra_digest;
89
90         if (unlikely((unsigned long)out & alignmask)) {
91                 unsigned long align = alignmask + 1;
92                 unsigned long addr = (unsigned long)crypto_tfm_ctx(tfm);
93                 u8 *dst = (u8 *)ALIGN(addr, align) +
94                           ALIGN(tfm->__crt_alg->cra_ctxsize, align);
95
96                 digest->dia_final(tfm, dst);
97                 memcpy(out, dst, digest->dia_digestsize);
98         } else
99                 digest->dia_final(tfm, out);
100
101         return 0;
102 }
103
104 static int nosetkey(struct crypto_hash *tfm, const u8 *key, unsigned int keylen)
105 {
106         crypto_hash_clear_flags(tfm, CRYPTO_TFM_RES_MASK);
107         return -ENOSYS;
108 }
109
110 static int setkey(struct crypto_hash *hash, const u8 *key, unsigned int keylen)
111 {
112         struct crypto_tfm *tfm = crypto_hash_tfm(hash);
113
114         crypto_hash_clear_flags(hash, CRYPTO_TFM_RES_MASK);
115         return tfm->__crt_alg->cra_digest.dia_setkey(tfm, key, keylen);
116 }
117
118 static int digest(struct hash_desc *desc,
119                   struct scatterlist *sg, unsigned int nbytes, u8 *out)
120 {
121         init(desc);
122         update(desc, sg, nbytes);
123         return final(desc, out);
124 }
125
126 int crypto_init_digest_flags(struct crypto_tfm *tfm, u32 flags)
127 {
128         return flags ? -EINVAL : 0;
129 }
130
131 int crypto_init_digest_ops(struct crypto_tfm *tfm)
132 {
133         struct hash_tfm *ops = &tfm->crt_hash;
134         struct digest_alg *dalg = &tfm->__crt_alg->cra_digest;
135
136         if (dalg->dia_digestsize > crypto_tfm_alg_blocksize(tfm))
137                 return -EINVAL;
138         
139         ops->init       = init;
140         ops->update     = update;
141         ops->final      = final;
142         ops->digest     = digest;
143         ops->setkey     = dalg->dia_setkey ? setkey : nosetkey;
144         ops->digestsize = dalg->dia_digestsize;
145         
146         return 0;
147 }
148
149 void crypto_exit_digest_ops(struct crypto_tfm *tfm)
150 {
151 }