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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* cryptsetup plain device helper functions
*
* Copyright (C) 2004 Jana Saout <jana@saout.de>
* Copyright (C) 2010-2025 Red Hat, Inc. All rights reserved.
* Copyright (C) 2010-2025 Milan Broz
*/
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include "libcryptsetup.h"
#include "internal.h"
static int hash(const char *hash_name, size_t key_size, char *key,
size_t passphrase_size, const char *passphrase)
{
struct crypt_hash *md = NULL;
size_t len;
int round, i, r = 0;
if (crypt_hash_init(&md, hash_name))
return -ENOENT;
len = crypt_hash_size(hash_name);
for(round = 0; key_size && !r; round++) {
/* hack from hashalot to avoid null bytes in key */
for(i = 0; i < round; i++)
if (crypt_hash_write(md, "A", 1))
r = 1;
if (crypt_hash_write(md, passphrase, passphrase_size))
r = 1;
if (len > key_size)
len = key_size;
if (crypt_hash_final(md, key, len))
r = 1;
key += len;
key_size -= len;
}
crypt_hash_destroy(md);
return r;
}
#define PLAIN_HASH_LEN_MAX 256
int crypt_plain_hash(struct crypt_device *cd,
const char *hash_name,
char *key, size_t key_size,
const char *passphrase, size_t passphrase_size)
{
char hash_name_buf[PLAIN_HASH_LEN_MAX], *s;
size_t hash_size, pad_size;
int r;
log_dbg(cd, "Plain: hashing passphrase using %s.", hash_name);
if (strlen(hash_name) >= PLAIN_HASH_LEN_MAX)
return -EINVAL;
strncpy(hash_name_buf, hash_name, PLAIN_HASH_LEN_MAX);
hash_name_buf[PLAIN_HASH_LEN_MAX - 1] = '\0';
/* hash[:hash_length] */
if ((s = strchr(hash_name_buf, ':'))) {
*s = '\0';
s++;
if (!*s || sscanf(s, "%zd", &hash_size) != 1) {
log_dbg(cd, "Hash length is not a number");
return -EINVAL;
}
if (hash_size > key_size) {
log_dbg(cd, "Hash length %zd > key length %zd",
hash_size, key_size);
return -EINVAL;
}
pad_size = key_size - hash_size;
} else {
hash_size = key_size;
pad_size = 0;
}
/* No hash, copy passphrase directly */
if (!strcmp(hash_name_buf, "plain")) {
if (passphrase_size < hash_size) {
log_dbg(cd, "Too short plain passphrase.");
return -EINVAL;
}
crypt_safe_memcpy(key, passphrase, hash_size);
r = 0;
} else
r = hash(hash_name_buf, hash_size, key, passphrase_size, passphrase);
if (r == 0 && pad_size)
memset(key + hash_size, 0, pad_size);
return r;
}
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