summaryrefslogtreecommitdiffstats
path: root/crypto/digest.c
blob: c06089db5a2455082ad05d3fe65f885437685512 (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
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
/*
 * (C) Copyright 2008-2010 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * 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; version 2 of
 * the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <common.h>
#include <digest.h>
#include <malloc.h>
#include <fs.h>
#include <fcntl.h>
#include <linux/stat.h>
#include <errno.h>
#include <module.h>
#include <linux/err.h>

static LIST_HEAD(digests);

static struct digest_algo *digest_algo_get_by_name(const char *name);

static int dummy_init(struct digest *d)
{
	return 0;
}

static void dummy_free(struct digest *d) {}

int digest_algo_register(struct digest_algo *d)
{
	if (!d || !d->name || !d->update || !d->final || d->length < 1)
		return -EINVAL;

	if (!d->init)
		d->init = dummy_init;

	if (!d->alloc)
		d->alloc = dummy_init;

	if (!d->free)
		d->free = dummy_free;

	if (digest_algo_get_by_name(d->name))
		return -EEXIST;

	list_add_tail(&d->list, &digests);

	return 0;
}
EXPORT_SYMBOL(digest_algo_register);

void digest_algo_unregister(struct digest_algo *d)
{
	if (!d)
		return;

	list_del(&d->list);
}
EXPORT_SYMBOL(digest_algo_unregister);

static struct digest_algo *digest_algo_get_by_name(const char *name)
{
	struct digest_algo *d;

	if (!name)
		return NULL;

	list_for_each_entry(d, &digests, list) {
		if(strcmp(d->name, name) == 0)
			return d;
	}

	return NULL;
}

struct digest *digest_alloc(const char *name)
{
	struct digest *d;
	struct digest_algo *algo;

	algo = digest_algo_get_by_name(name);
	if (!algo)
		return NULL;

	d = xzalloc(sizeof(*d));
	d->algo = algo;
	d->ctx = xzalloc(algo->ctx_length);
	if (d->algo->alloc(d)) {
		digest_free(d);
		return NULL;
	}

	return d;
}
EXPORT_SYMBOL_GPL(digest_alloc);

void digest_free(struct digest *d)
{
	if (!d)
		return;
	d->algo->free(d);
	free(d->ctx);
	free(d);
}
EXPORT_SYMBOL_GPL(digest_free);

int digest_file_window(struct digest *d, const char *filename,
		       const unsigned char *key, size_t keylen,
		       unsigned char *hash,
		       ulong start, ulong size)
{
	ulong len = 0;
	int fd, now, ret = 0;
	unsigned char *buf;
	int flags = 0;

	if (key)
		digest_set_key(d, key, keylen);

	digest_init(d);

	fd = open(filename, O_RDONLY);
	if (fd < 0) {
		perror(filename);
		return fd;
	}

	buf = memmap(fd, PROT_READ);
	if (buf == (void *)-1) {
		buf = xmalloc(4096);
		flags = 1;
	}

	if (start > 0) {
		if (flags) {
			ret = lseek(fd, start, SEEK_SET);
			if (ret == -1) {
				perror("lseek");
				goto out;
			}
		} else {
			buf += start;
		}
	}

	while (size) {
		now = min((ulong)4096, size);
		if (flags) {
			now = read(fd, buf, now);
			if (now < 0) {
				ret = now;
				perror("read");
				goto out_free;
			}
			if (!now)
				break;
		}

		if (ctrlc()) {
			ret = -EINTR;
			goto out_free;
		}

		digest_update(d, buf, now);
		size -= now;
		len += now;
	}

	digest_final(d, hash);

out_free:
	if (flags)
		free(buf);
out:
	close(fd);

	return ret;
}
EXPORT_SYMBOL_GPL(digest_file_window);

int digest_file(struct digest *d, const char *filename,
		       const unsigned char *key, size_t keylen,
		       unsigned char *hash)
{
	struct stat st;
	int ret;

	ret = stat(filename, &st);

	if (ret < 0)
		return ret;

	return digest_file_window(d, filename, key, keylen, hash, 0, st.st_size);
}
EXPORT_SYMBOL_GPL(digest_file);

int digest_file_by_name(const char *algo, const char *filename,
		       const unsigned char *key, size_t keylen,
		       unsigned char *hash)
{
	struct digest *d;
	int ret;

	d = digest_alloc(algo);
	if (!d)
		return -EIO;

	ret = digest_file(d, filename, key, keylen, hash);
	digest_free(d);
	return ret;
}
EXPORT_SYMBOL_GPL(digest_file_by_name);