118 lines
3.0 KiB
C
118 lines
3.0 KiB
C
/*
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* cryptsetup plain device helper functions
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*
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* Copyright (C) 2004 Jana Saout <jana@saout.de>
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* Copyright (C) 2010-2023 Red Hat, Inc. All rights reserved.
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* Copyright (C) 2010-2023 Milan Broz
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include <string.h>
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#include <stdio.h>
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#include <errno.h>
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#include "libcryptsetup.h"
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#include "internal.h"
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static int hash(const char *hash_name, size_t key_size, char *key,
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size_t passphrase_size, const char *passphrase)
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{
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struct crypt_hash *md = NULL;
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size_t len;
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int round, i, r = 0;
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if (crypt_hash_init(&md, hash_name))
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return -ENOENT;
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len = crypt_hash_size(hash_name);
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for(round = 0; key_size && !r; round++) {
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/* hack from hashalot to avoid null bytes in key */
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for(i = 0; i < round; i++)
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if (crypt_hash_write(md, "A", 1))
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r = 1;
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if (crypt_hash_write(md, passphrase, passphrase_size))
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r = 1;
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if (len > key_size)
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len = key_size;
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if (crypt_hash_final(md, key, len))
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r = 1;
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key += len;
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key_size -= len;
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}
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crypt_hash_destroy(md);
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return r;
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}
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#define PLAIN_HASH_LEN_MAX 256
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int crypt_plain_hash(struct crypt_device *cd,
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const char *hash_name,
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char *key, size_t key_size,
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const char *passphrase, size_t passphrase_size)
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{
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char hash_name_buf[PLAIN_HASH_LEN_MAX], *s;
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size_t hash_size, pad_size;
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int r;
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log_dbg(cd, "Plain: hashing passphrase using %s.", hash_name);
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if (strlen(hash_name) >= PLAIN_HASH_LEN_MAX)
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return -EINVAL;
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strncpy(hash_name_buf, hash_name, PLAIN_HASH_LEN_MAX);
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hash_name_buf[PLAIN_HASH_LEN_MAX - 1] = '\0';
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/* hash[:hash_length] */
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if ((s = strchr(hash_name_buf, ':'))) {
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*s = '\0';
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s++;
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if (!*s || sscanf(s, "%zd", &hash_size) != 1) {
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log_dbg(cd, "Hash length is not a number");
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return -EINVAL;
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}
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if (hash_size > key_size) {
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log_dbg(cd, "Hash length %zd > key length %zd",
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hash_size, key_size);
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return -EINVAL;
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}
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pad_size = key_size - hash_size;
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} else {
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hash_size = key_size;
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pad_size = 0;
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}
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/* No hash, copy passphrase directly */
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if (!strcmp(hash_name_buf, "plain")) {
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if (passphrase_size < hash_size) {
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log_dbg(cd, "Too short plain passphrase.");
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return -EINVAL;
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}
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memcpy(key, passphrase, hash_size);
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r = 0;
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} else
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r = hash(hash_name_buf, hash_size, key, passphrase_size, passphrase);
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if (r == 0 && pad_size)
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memset(key + hash_size, 0, pad_size);
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return r;
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}
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