summaryrefslogtreecommitdiffstats
path: root/crypto/digest.c
blob: 6fd43bddd545e788546d868b097e3ad811867e76 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
/*
 * Cryptographic API.
 *
 * Digest operations.
 *
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option) 
 * any later version.
 *
 */

#include <crypto/scatterwalk.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/hardirq.h>
#include <linux/highmem.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/scatterlist.h>

static int init(struct hash_desc *desc)
{
	struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);

	tfm->__crt_alg->cra_digest.dia_init(tfm);
	return 0;
}

static int update2(struct hash_desc *desc,
		   struct scatterlist *sg, unsigned int nbytes)
{
	struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
	unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);

	if (!nbytes)
		return 0;

	for (;;) {
		struct page *pg = sg_page(sg);
		unsigned int offset = sg->offset;
		unsigned int l = sg->length;

		if (unlikely(l > nbytes))
			l = nbytes;
		nbytes -= l;

		do {
			unsigned int bytes_from_page = min(l, ((unsigned int)
							   (PAGE_SIZE)) - 
							   offset);
			char *src = crypto_kmap(pg, 0);
			char *p = src + offset;

			if (unlikely(offset & alignmask)) {
				unsigned int bytes =
					alignmask + 1 - (offset & alignmask);
				bytes = min(bytes, bytes_from_page);
				tfm->__crt_alg->cra_digest.dia_update(tfm, p,
								      bytes);
				p += bytes;
				bytes_from_page -= bytes;
				l -= bytes;
			}
			tfm->__crt_alg->cra_digest.dia_update(tfm, p,
							      bytes_from_page);
			crypto_kunmap(src, 0);
			crypto_yield(desc->flags);
			offset = 0;
			pg++;
			l -= bytes_from_page;
		} while (l > 0);

		if (!nbytes)
			break;
		sg = scatterwalk_sg_next(sg);
	}

	return 0;
}

static int update(struct hash_desc *desc,
		  struct scatterlist *sg, unsigned int nbytes)
{
	if (WARN_ON_ONCE(in_irq()))
		return -EDEADLK;
	return update2(desc, sg, nbytes);
}

static int final(struct hash_desc *desc, u8 *out)
{
	struct crypto_tfm *tfm = crypto_hash_tfm(desc->tfm);
	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
	struct digest_alg *digest = &tfm->__crt_alg->cra_digest;

	if (unlikely((unsigned long)out & alignmask)) {
		unsigned long align = alignmask + 1;
		unsigned long addr = (unsigned long)crypto_tfm_ctx(tfm);
		u8 *dst = (u8 *)ALIGN(addr, align) +
			  ALIGN(tfm->__crt_alg->cra_ctxsize, align);

		digest->dia_final(tfm, dst);
		memcpy(out, dst, digest->dia_digestsize);
	} else
		digest->dia_final(tfm, out);

	return 0;
}

static int nosetkey(struct crypto_hash *tfm, const u8 *key, unsigned int keylen)
{
	crypto_hash_clear_flags(tfm, CRYPTO_TFM_RES_MASK);
	return -ENOSYS;
}

static int setkey(struct crypto_hash *hash, const u8 *key, unsigned int keylen)
{
	struct crypto_tfm *tfm = crypto_hash_tfm(hash);

	crypto_hash_clear_flags(hash, CRYPTO_TFM_RES_MASK);
	return tfm->__crt_alg->cra_digest.dia_setkey(tfm, key, keylen);
}

static int digest(struct hash_desc *desc,
		  struct scatterlist *sg, unsigned int nbytes, u8 *out)
{
	if (WARN_ON_ONCE(in_irq()))
		return -EDEADLK;

	init(desc);
	update2(desc, sg, nbytes);
	return final(desc, out);
}

int crypto_init_digest_ops(struct crypto_tfm *tfm)
{
	struct hash_tfm *ops = &tfm->crt_hash;
	struct digest_alg *dalg = &tfm->__crt_alg->cra_digest;

	if (dalg->dia_digestsize > crypto_tfm_alg_blocksize(tfm))
		return -EINVAL;
	
	ops->init	= init;
	ops->update	= update;
	ops->final	= final;
	ops->digest	= digest;
	ops->setkey	= dalg->dia_setkey ? setkey : nosetkey;
	ops->digestsize	= dalg->dia_digestsize;
	
	return 0;
}

void crypto_exit_digest_ops(struct crypto_tfm *tfm)
{
}