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Diffstat (limited to '')
| -rw-r--r-- | lib/utils_crypt.c | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/lib/utils_crypt.c b/lib/utils_crypt.c new file mode 100644 index 0000000..6b189c9 --- /dev/null +++ b/lib/utils_crypt.c @@ -0,0 +1,249 @@ +/* + * utils_crypt - cipher utilities for cryptsetup + * + * Copyright (C) 2004-2007 Clemens Fruhwirth <clemens@endorphin.org> + * Copyright (C) 2009-2019 Red Hat, Inc. All rights reserved. + * Copyright (C) 2009-2019 Milan Broz + * + * 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. + * + * 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. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <errno.h> + +#include "libcryptsetup.h" +#include "utils_crypt.h" + +int crypt_parse_name_and_mode(const char *s, char *cipher, int *key_nums, + char *cipher_mode) +{ + if (!s || !cipher || !cipher_mode) + return -EINVAL; + + if (sscanf(s, "%" MAX_CIPHER_LEN_STR "[^-]-%" MAX_CIPHER_LEN_STR "s", + cipher, cipher_mode) == 2) { + if (!strcmp(cipher_mode, "plain")) + strcpy(cipher_mode, "cbc-plain"); + if (key_nums) { + char *tmp = strchr(cipher, ':'); + *key_nums = tmp ? atoi(++tmp) : 1; + if (!*key_nums) + return -EINVAL; + } + + return 0; + } + + /* Short version for "empty" cipher */ + if (!strcmp(s, "null") || !strcmp(s, "cipher_null")) { + strcpy(cipher, "cipher_null"); + strcpy(cipher_mode, "ecb"); + if (key_nums) + *key_nums = 0; + return 0; + } + + if (sscanf(s, "%" MAX_CIPHER_LEN_STR "[^-]", cipher) == 1) { + strcpy(cipher_mode, "cbc-plain"); + if (key_nums) + *key_nums = 1; + return 0; + } + + return -EINVAL; +} + +int crypt_parse_hash_integrity_mode(const char *s, char *integrity) +{ + char mode[MAX_CIPHER_LEN], hash[MAX_CIPHER_LEN]; + int r; + + if (!s || !integrity || strchr(s, '(') || strchr(s, ')')) + return -EINVAL; + + r = sscanf(s, "%" MAX_CIPHER_LEN_STR "[^-]-%" MAX_CIPHER_LEN_STR "s", mode, hash); + if (r == 2) + r = snprintf(integrity, MAX_CIPHER_LEN, "%s(%s)", mode, hash); + else if (r == 1) + r = snprintf(integrity, MAX_CIPHER_LEN, "%s", mode); + else + return -EINVAL; + + if (r < 0 || r == MAX_CIPHER_LEN) + return -EINVAL; + + return 0; +} + +int crypt_parse_integrity_mode(const char *s, char *integrity, + int *integrity_key_size) +{ + int ks = 0, r = 0; + + if (!s || !integrity) + return -EINVAL; + + // FIXME: do not hardcode it here + + /* AEAD modes */ + if (!strcmp(s, "aead") || + !strcmp(s, "poly1305") || + !strcmp(s, "none")) { + strncpy(integrity, s, MAX_CIPHER_LEN); + ks = 0; + } else if (!strcmp(s, "hmac-sha1")) { + strncpy(integrity, "hmac(sha1)", MAX_CIPHER_LEN); + ks = 20; + } else if (!strcmp(s, "hmac-sha256")) { + strncpy(integrity, "hmac(sha256)", MAX_CIPHER_LEN); + ks = 32; + } else if (!strcmp(s, "hmac-sha512")) { + ks = 64; + strncpy(integrity, "hmac(sha512)", MAX_CIPHER_LEN); + } else if (!strcmp(s, "cmac-aes")) { + ks = 16; + strncpy(integrity, "cmac(aes)", MAX_CIPHER_LEN); + } else + r = -EINVAL; + + if (integrity_key_size) + *integrity_key_size = ks; + + return r; +} + +int crypt_parse_pbkdf(const char *s, const char **pbkdf) +{ + const char *tmp = NULL; + + if (!s) + return -EINVAL; + + if (!strcasecmp(s, CRYPT_KDF_PBKDF2)) + tmp = CRYPT_KDF_PBKDF2; + else if (!strcasecmp(s, CRYPT_KDF_ARGON2I)) + tmp = CRYPT_KDF_ARGON2I; + else if (!strcasecmp(s, CRYPT_KDF_ARGON2ID)) + tmp = CRYPT_KDF_ARGON2ID; + + if (!tmp) + return -EINVAL; + + if (pbkdf) + *pbkdf = tmp; + + return 0; +} + +/* + * Replacement for memset(s, 0, n) on stack that can be optimized out + * Also used in safe allocations for explicit memory wipe. + */ +void crypt_memzero(void *s, size_t n) +{ +#ifdef HAVE_EXPLICIT_BZERO + explicit_bzero(s, n); +#else + volatile uint8_t *p = (volatile uint8_t *)s; + + while(n--) + *p++ = 0; +#endif +} + +/* safe allocations */ +void *crypt_safe_alloc(size_t size) +{ + struct safe_allocation *alloc; + + if (!size || size > (SIZE_MAX - offsetof(struct safe_allocation, data))) + return NULL; + + alloc = malloc(size + offsetof(struct safe_allocation, data)); + if (!alloc) + return NULL; + + alloc->size = size; + crypt_memzero(&alloc->data, size); + + /* coverity[leaked_storage] */ + return &alloc->data; +} + +void crypt_safe_free(void *data) +{ + struct safe_allocation *alloc; + + if (!data) + return; + + alloc = (struct safe_allocation *) + ((char *)data - offsetof(struct safe_allocation, data)); + + crypt_memzero(data, alloc->size); + + alloc->size = 0x55aa55aa; + free(alloc); +} + +void *crypt_safe_realloc(void *data, size_t size) +{ + struct safe_allocation *alloc; + void *new_data; + + new_data = crypt_safe_alloc(size); + + if (new_data && data) { + + alloc = (struct safe_allocation *) + ((char *)data - offsetof(struct safe_allocation, data)); + + if (size > alloc->size) + size = alloc->size; + + memcpy(new_data, data, size); + } + + crypt_safe_free(data); + return new_data; +} + +ssize_t crypt_hex_to_bytes(const char *hex, char **result, int safe_alloc) +{ + char buf[3] = "xx\0", *endp, *bytes; + size_t i, len; + + len = strlen(hex); + if (len % 2) + return -EINVAL; + len /= 2; + + bytes = safe_alloc ? crypt_safe_alloc(len) : malloc(len); + if (!bytes) + return -ENOMEM; + + for (i = 0; i < len; i++) { + memcpy(buf, &hex[i * 2], 2); + bytes[i] = strtoul(buf, &endp, 16); + if (endp != &buf[2]) { + safe_alloc ? crypt_safe_free(bytes) : free(bytes); + return -EINVAL; + } + } + *result = bytes; + return i; +} |