Add loop-AES compatible handling code.

git-svn-id: https://cryptsetup.googlecode.com/svn/trunk@418 36d66b0a-2a48-0410-832c-cd162a569da5

ChangeLog

+2011-01-25  Milan Broz  <mbroz@redhat.com>
+	* Add loop-AES handling (loopaesOpen and loopaesClose commands).
+	 (requires kernel 2.6.38 and above)
+
 2011-01-05  Milan Broz  <mbroz@redhat.com>
 	* Fix static build (--disable-static-cryptsetup now works properly).
 

configure.in

@@ -257,6 +257,7 @@ lib/Makefile
 lib/libcryptsetup.pc
 lib/crypto_backend/Makefile
 lib/luks1/Makefile
+lib/loopaes/Makefile
 src/Makefile
 po/Makefile.in
 man/Makefile

lib/Makefile.am

-SUBDIRS = crypto_backend luks1
+SUBDIRS = crypto_backend luks1 loopaes
 
 moduledir = $(libdir)/cryptsetup
 
@@ -9,6 +9,7 @@ INCLUDES = \
 	-I$(top_srcdir)				\
 	-I$(top_srcdir)/lib/crypto_backend	\
 	-I$(top_srcdir)/lib/luks1		\
+	-I$(top_srcdir)/lib/loopaes		\
 	-DDATADIR=\""$(datadir)"\"		\
 	-DLIBDIR=\""$(libdir)"\"		\
 	-DPREFIX=\""$(prefix)"\"		\
@@ -20,7 +21,12 @@ INCLUDES = \
 
 lib_LTLIBRARIES = libcryptsetup.la
 
-libcryptsetup_la_DEPENDENCIES = libcryptsetup.sym
+common_ldadd = \
+	crypto_backend/libcrypto_backend.la	\
+	luks1/libluks1.la			\
+	loopaes/libloopaes.la
+
+libcryptsetup_la_DEPENDENCIES = $(common_ldadd) libcryptsetup.sym
 
 libcryptsetup_la_LDFLAGS = \
 	-Wl,--version-script=$(top_srcdir)/lib/libcryptsetup.sym \
@@ -32,8 +38,8 @@ libcryptsetup_la_LIBADD = \
 	@UUID_LIBS@				\
 	@DEVMAPPER_LIBS@			\
 	@CRYPTO_LIBS@				\
-	crypto_backend/libcrypto_backend.la	\
-	luks1/libluks1.la
+	$(common_ldadd)
+
 
 libcryptsetup_la_SOURCES = \
 	setup.c					\

lib/libcryptsetup.h

@@ -146,6 +146,7 @@ int crypt_memory_lock(struct crypt_device *cd, int lock);
 
 #define CRYPT_PLAIN "PLAIN" /* regular crypt device, no on-disk header */
 #define CRYPT_LUKS1 "LUKS1" /* LUKS version 1 header on-disk */
+#define CRYPT_LOOPAES "LOOPAES" /* loop-AES compatibility mode */
 
 /**
  * Get device type
@@ -167,6 +168,10 @@ struct crypt_params_luks1 {
 	size_t data_alignment; /* in sectors, data offset is multiple of this */
 };
 
+struct crypt_params_loopaes {
+	const char *hash; /* key hash function */
+	uint64_t offset;  /* offset in sectors */
+};
 /**
  * Create (format) new crypt device (and possible header on-disk) but not activates it.
  *

lib/loopaes/Makefile.am

+moduledir = $(libdir)/cryptsetup
+
+noinst_LTLIBRARIES = libloopaes.la
+
+libloopaes_la_CFLAGS = -Wall @CRYPTO_CFLAGS@
+
+libloopaes_la_SOURCES = \
+	loopaes.c \
+	loopaes.h
+
+INCLUDES = -D_GNU_SOURCE			\
+	-D_LARGEFILE64_SOURCE                   \
+	-D_FILE_OFFSET_BITS=64                  \
+        -I$(top_srcdir)/lib			\
+        -I$(top_srcdir)/lib/crypto_backend
+

lib/loopaes/loopaes.c

+/*
+ * loop-AES compatible volume handling
+ *
+ * Copyright (C) 2011, Red Hat, Inc. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "crypto_backend.h"
+#include "loopaes.h"
+
+static const char *get_hash(unsigned int key_size)
+{
+	char *hash;
+
+	switch (key_size) {
+		case 16: hash = "sha256"; break;
+		case 24: hash = "sha384"; break;
+		case 32: hash = "sha512"; break;
+		default: hash = NULL;
+	}
+
+	return hash;
+}
+
+static unsigned char get_tweak(unsigned int keys_count)
+{
+	switch (keys_count) {
+		case 64: return 0x55;
+		case 65: return 0xF4;
+		default: break;
+	}
+	return 0x00;
+}
+
+static int hash_key(const char *src, size_t src_len,
+		    char *dst, size_t dst_len,
+		    const char *hash_name)
+{
+	struct crypt_hash *hd = NULL;
+
+	if (crypt_hash_init(&hd, hash_name))
+		return -EINVAL;
+	crypt_hash_write(hd, src, src_len);
+	crypt_hash_final(hd, dst, dst_len);
+	crypt_hash_destroy(hd);
+	return 0;
+}
+
+static int hash_keys(struct volume_key **vk,
+		     const char **input_keys,
+		     unsigned int keys_count,
+		     unsigned int key_len_output)
+{
+	const char *hash_name;
+	char tweak, *key_ptr;
+	int r, i, key_len_input;
+
+	hash_name = get_hash(key_len_output);
+	tweak = get_tweak(keys_count);
+	key_len_input = strlen(input_keys[0]);
+
+	if (!keys_count || !key_len_output || !hash_name || !key_len_input)
+		return -EINVAL;
+
+	*vk = crypt_alloc_volume_key(key_len_output * keys_count, NULL);
+	if (!*vk)
+		return -ENOMEM;
+
+	for (i = 0; i < keys_count; i++) {
+		key_ptr = &(*vk)->key[i * key_len_output];
+		r = hash_key(input_keys[i], key_len_input, key_ptr,
+			     key_len_output, hash_name);
+		if (r < 0)
+			break;
+
+		key_ptr[0] ^= tweak;
+	}
+
+	if (r < 0 && *vk) {
+		crypt_free_volume_key(*vk);
+		*vk = NULL;
+	}
+	return r;
+}
+
+static int keyfile_is_gpg(char *buffer, unsigned int buffer_len)
+{
+	int r = 0;
+	int index = buffer_len < 100 ? buffer_len - 1 : 100;
+	char eos = buffer[index];
+
+	buffer[index] = '\0';
+	if (strstr(buffer, "BEGIN PGP MESSAGE"))
+		r = 1;
+	buffer[index] = eos;
+	return r;
+}
+
+int LOOPAES_parse_keyfile(struct crypt_device *cd,
+			  struct volume_key **vk,
+			  unsigned int *keys_count,
+			  char *buffer,
+			  unsigned int buffer_len)
+
+{
+	const char *keys[LOOPAES_KEYS_MAX];
+	int i, key_index, key_len, offset;
+
+	log_dbg("Parsing loop-AES keyfile of size %d.", buffer_len);
+
+	if (buffer_len < LOOPAES_KEYFILE_MINSIZE) {
+		log_err(cd, _("Incompatible loop-AES keyfile detected.\n"));
+		return -EINVAL;
+	}
+
+	if (keyfile_is_gpg(buffer, buffer_len)) {
+		log_err(cd, "Detected not yet supported GPG encrypted keyfile.\n");
+		log_std(cd, "Please use gpg --decrypt <KEYFILE> | cryptsetup --keyfile=- ...\n");
+		return -EINVAL;
+	}
+
+	/* Remove EOL in buffer */
+	for (i = 0; i < buffer_len; i++)
+		if (buffer[i] == '\n' || buffer[i] == '\r')
+			buffer[i] = '\0';
+
+	offset = 0;
+	key_index = 0;
+	while (offset < buffer_len && key_index < LOOPAES_KEYS_MAX) {
+		keys[key_index++] = &buffer[offset];
+		while (offset < buffer_len && buffer[offset])
+			offset++;
+		while (offset < buffer_len && !buffer[offset])
+			offset++;
+	}
+
+	/* All keys must be the same length */
+	key_len = key_index ? strlen(keys[0]) : 0;
+	for (i = 0; i < key_index; i++)
+		if (key_len != strlen(keys[i])) {
+			log_dbg("Unexpected length %d of key #%d (should be %d).",
+				strlen(keys[i]), i, key_len);
+			key_len = 0;
+			break;
+		}
+
+	log_dbg("Keyfile: %d keys of length %d.", key_index, key_len);
+	if (offset != buffer_len || key_len == 0 ||
+	   (key_index != 1 && key_index !=64 && key_index != 65)) {
+		log_err(cd, _("Incompatible loop-AES keyfile detected.\n"));
+		return -EINVAL;
+	}
+
+	*keys_count = key_index;
+	return hash_keys(vk, keys, key_index, crypt_get_volume_key_size(cd));
+}
+
+int LOOPAES_activate(struct crypt_device *cd,
+		     const char *name,
+		     const char *base_cipher,
+		     unsigned int keys_count,
+		     struct volume_key *vk,
+		     uint32_t flags)
+{
+	uint64_t size, offset;
+	char *cipher;
+	const char *device;
+	int read_only, r;
+
+	size = 0;
+	offset = crypt_get_data_offset(cd);
+	device = crypt_get_device_name(cd);
+	read_only = flags & CRYPT_ACTIVATE_READONLY;
+
+	r = device_check_and_adjust(cd, device, 1, &size, &offset, &read_only);
+	if (r)
+		return r;
+
+	if (keys_count == 1) {
+		if (asprintf(&cipher, "%s-%s", base_cipher, "cbc-plain") < 0)
+			return -ENOMEM;
+	} else {
+		if (!(dm_flags() & DM_LMK_SUPPORTED)) {
+			log_err(cd, _("Kernel doesn't support loop-AES compatible mapping.\n"));
+			return -ENOTSUP;
+		}
+		if (asprintf(&cipher, "%s:%d-%s", base_cipher, 64, "cbc-lmk") < 0)
+			return -ENOMEM;
+	}
+
+	log_dbg("Trying to activate loop-AES device %s using cipher %s.", name, cipher);
+	r = dm_create_device(name, device,
+			     cipher, CRYPT_LOOPAES,
+			     crypt_get_uuid(cd),
+			     size, 0, offset, vk->keylength, vk->key,
+			     read_only, 0);
+	free(cipher);
+	return r;
+}

lib/loopaes/loopaes.h

+#ifndef _LOOPAES_H
+#define _LOOPAES_H
+
+#define LOOPAES_KEYS_MAX 65
+#define LOOPAES_KEYFILE_MINSIZE 60
+#define LOOPAES_KEYFILE_MAXSIZE 8000
+
+#define DEFAULT_LOOPAES_CIPHER "aes"
+
+int LOOPAES_parse_keyfile(struct crypt_device *cd,
+			  struct volume_key **vk,
+			  unsigned int *keys_count,
+			  char *buffer,
+			  unsigned int buffer_len);
+
+int LOOPAES_activate(struct crypt_device *cd,
+		     const char *name,
+		     const char *base_cipher,
+		     unsigned int keys_count,
+		     struct volume_key *vk,
+		     uint32_t flags);
+#endif

lib/setup.c

@@ -7,6 +7,7 @@
 
 #include "libcryptsetup.h"
 #include "luks.h"
+#include "loopaes.h"
 #include "internal.h"
 #include "crypto_backend.h"
 
@@ -31,6 +32,13 @@ struct crypt_device {
 	char *plain_cipher_mode;
 	char *plain_uuid;
 
+	/* used in CRYPT_LOOPAES */
+	struct crypt_params_loopaes loopaes_hdr;
+	char *loopaes_cipher;
+	char *loopaes_cipher_mode;
+	char *loopaes_uuid;
+	unsigned int loopaes_key_size;
+
 	/* callbacks definitions */
 	void (*log)(int level, const char *msg, void *usrptr);
 	void *log_usrptr;
@@ -160,6 +168,11 @@ static int isLUKS(const char *type)
 	return (type && !strcmp(CRYPT_LUKS1, type));
 }
 
+static int isLOOPAES(const char *type)
+{
+	return (type && !strcmp(CRYPT_LOOPAES, type));
+}
+
 /* keyslot helpers */
 static int keyslot_verify_or_find_empty(struct crypt_device *cd, int *keyslot)
 {
@@ -991,7 +1004,7 @@ int crypt_init_by_name(struct crypt_device **cd, const char *name)
 	char *device = NULL, *cipher_full = NULL, *device_uuid = NULL;
 	char cipher[MAX_CIPHER_LEN], cipher_mode[MAX_CIPHER_LEN];
 	char *key = NULL;
-	int key_size = 0, r;
+	int key_size = 0, key_nums, r;
 
 
 	log_dbg("Allocating crypt device context by device %s.", name);
@@ -1040,6 +1053,21 @@ int crypt_init_by_name(struct crypt_device **cd, const char *name)
 				(*cd)->plain_cipher = strdup(cipher);
 				(*cd)->plain_cipher_mode = strdup(cipher_mode);
 			}
+		} else if (!strncmp(CRYPT_LOOPAES, device_uuid, sizeof(CRYPT_LOOPAES)-1)) {
+			(*cd)->type = strdup(CRYPT_LOOPAES);
+			(*cd)->loopaes_uuid = strdup(device_uuid);
+			(*cd)->loopaes_hdr.offset = cad.offset;
+
+			r = crypt_parse_name_and_mode(cipher_full, cipher,
+						      &key_nums, cipher_mode);
+			if (!r) {
+				(*cd)->loopaes_cipher = strdup(cipher);
+				(*cd)->loopaes_cipher_mode = strdup(cipher_mode);
+				/* version 3 uses last key for IV */
+				if (key_size % key_nums)
+					key_nums++;
+				(*cd)->loopaes_key_size = key_size / key_nums;
+			}
 		} else if (!strncmp(CRYPT_LUKS1, device_uuid, sizeof(CRYPT_LUKS1)-1)) {
 			if (device) {
 				if (crypt_load(*cd, CRYPT_LUKS1, NULL) < 0 ||
@@ -1168,6 +1196,37 @@ static int _crypt_format_luks1(struct crypt_device *cd,
 	return r;
 }
 
+static int _crypt_format_loopaes(struct crypt_device *cd,
+				 const char *cipher,
+				 const char *uuid,
+				 size_t volume_key_size,
+				 struct crypt_params_loopaes *params)
+{
+	if (!cd->device) {
+		log_err(cd, _("Can't format LOOPAES without device.\n"));
+		return -EINVAL;
+	}
+
+	if (volume_key_size > 1024) {
+		log_err(cd, _("Invalid key size.\n"));
+		return -EINVAL;
+	}
+
+	cd->loopaes_key_size = volume_key_size;
+
+	cd->loopaes_cipher = strdup(cipher ?: DEFAULT_LOOPAES_CIPHER);
+
+	if (uuid)
+		cd->loopaes_uuid = strdup(uuid);
+
+	if (params && params->hash)
+		cd->loopaes_hdr.hash = strdup(params->hash);
+
+	cd->loopaes_hdr.offset = params ? params->offset : 0;
+
+	return 0;
+}
+
 int crypt_format(struct crypt_device *cd,
 	const char *type,
 	const char *cipher,
@@ -1194,6 +1253,8 @@ int crypt_format(struct crypt_device *cd,
 	else if (isLUKS(type))
 		r = _crypt_format_luks1(cd, cipher, cipher_mode,
 					uuid, volume_key, volume_key_size, params);
+	else if (isLOOPAES(type))
+		r = _crypt_format_loopaes(cd, cipher, uuid, volume_key_size, params);
 	else {
 		/* FIXME: allow plugins here? */
 		log_err(cd, _("Unknown crypt device type %s requested.\n"), type);
@@ -1815,7 +1876,7 @@ int crypt_activate_by_keyfile(struct crypt_device *cd,
 	crypt_status_info ci;
 	struct volume_key *vk = NULL;
 	char *passphrase_read = NULL;
-	unsigned int passphrase_size_read;
+	unsigned int passphrase_size_read, key_count = 0;
 	int r;
 
 	log_dbg("Activating volume %s [keyslot %d] using keyfile %s.",
@@ -1863,6 +1924,18 @@ int crypt_activate_by_keyfile(struct crypt_device *cd,
 				goto out;
 		}
 		r = keyslot;
+	} else if (isLOOPAES(cd->type)) {
+		r = key_from_file(cd, NULL, &passphrase_read, &passphrase_size_read,
+				  keyfile, LOOPAES_KEYFILE_MAXSIZE);
+		if (r < 0)
+			goto out;
+		r = LOOPAES_parse_keyfile(cd, &vk, &key_count,
+					  passphrase_read, passphrase_size_read);
+		if (r < 0)
+			goto out;
+		if (name)
+			r = LOOPAES_activate(cd, name, cd->loopaes_cipher,
+					     key_count, vk, flags);
 	} else
 		r = -EINVAL;
 
@@ -2185,6 +2258,9 @@ const char *crypt_get_cipher(struct crypt_device *cd)
 	if (isLUKS(cd->type))
 		return cd->hdr.cipherName;
 
+	if (isLOOPAES(cd->type))
+		return cd->loopaes_cipher;
+
 	return NULL;
 }
 
@@ -2196,6 +2272,9 @@ const char *crypt_get_cipher_mode(struct crypt_device *cd)
 	if (isLUKS(cd->type))
 		return cd->hdr.cipherMode;
 
+	if (isLOOPAES(cd->type))
+		return cd->loopaes_cipher_mode;
+
 	return NULL;
 }
 
@@ -2207,6 +2286,9 @@ const char *crypt_get_uuid(struct crypt_device *cd)
 	if (isPLAIN(cd->type))
 		return cd->plain_uuid;
 
+	if (isLOOPAES(cd->type))
+		return cd->loopaes_uuid;
+
 	return NULL;
 }
 
@@ -2223,6 +2305,9 @@ int crypt_get_volume_key_size(struct crypt_device *cd)
 	if (isLUKS(cd->type))
 		return cd->hdr.keyBytes;
 
+	if (isLOOPAES(cd->type))
+		return cd->loopaes_key_size;
+
 	return 0;
 }
 
@@ -2234,6 +2319,9 @@ uint64_t crypt_get_data_offset(struct crypt_device *cd)
 	if (isLUKS(cd->type))
 		return cd->hdr.payloadOffset;
 
+	if (isLOOPAES(cd->type))
+		return cd->loopaes_hdr.offset;
+
 	return 0;
 }
 

man/cryptsetup.8

@@ -134,6 +134,26 @@ This command allows restoring header if device do not contain LUKS header or if
 
 For more information about LUKS, see \fBhttp://code.google.com/p/cryptsetup/wiki/Specification\fR
 
+.SH Loop-AES EXTENSION
+
+cryptsetup allows to map loop-AES encrypted partition using compatible dm-crypt mode.
+
+.PP
+\fIloopaesOpen\fR <device> <name> \-\-key-file <keyfile>
+.IP
+opens the loop-AES <device> and sets up a mapping <name>.
+
+N.B. If keyfile is in GPG encrypted format, you have to use \-\-key-file=- and decrypt it before use.
+gpg --decrypt <keyfile> | cryptsetup loopaesOpen \-\-key-file=- <device> <name>
+
+\fB<options>\fR can be [\-\-key-file, \-\-key-size, \-\-offset, \-\-readonly].
+.PP
+\fIloopaesClose\fR <name>
+.IP
+identical to \fIremove\fR.
+.PP
+For more information about loop-AES, see \fBhttp://loop-aes.sourceforge.net\fR
+
 .SH OPTIONS
 .TP
 .B "\-\-verbose, \-v"

src/cryptsetup.c

@@ -62,6 +62,7 @@ static int action_luksSuspend(int arg);
 static int action_luksResume(int arg);
 static int action_luksBackup(int arg);
 static int action_luksRestore(int arg);
+static int action_loopaesOpen(int arg);
 
 static struct action_type {
 	const char *type;
@@ -89,6 +90,8 @@ static struct action_type {
 	{ "luksResume",	action_luksResume,	0, 1, 1, N_("<device>"), N_("Resume suspended LUKS device.") },
 	{ "luksHeaderBackup",action_luksBackup,	0, 1, 1, N_("<device>"), N_("Backup LUKS device header and keyslots") },
 	{ "luksHeaderRestore",action_luksRestore,0,1, 1, N_("<device>"), N_("Restore LUKS device header and keyslots") },
+	{ "loopaesOpen",action_loopaesOpen,	0, 2, 1, N_("<device> <name> "), N_("open loop-AES device as mapping <name>") },
+	{ "loopaesClose",action_remove,		0, 1, 1, N_("<name>"), N_("remove loop-AES mapping") },
 	{ NULL, NULL, 0, 0, 0, NULL, NULL }
 };
 
@@ -253,6 +256,38 @@ out:
 	return r;
 }
 
+static int action_loopaesOpen(int arg)
+{
+	struct crypt_device *cd = NULL;
+	struct crypt_params_loopaes params = {
+		.hash = opt_hash ?: NULL, // FIXME
+		.offset = opt_offset,
+	};
+	unsigned int key_size = (opt_key_size ?: 128) / 8;
+	int r;
+
+	if (!opt_key_file) {
+		log_err(_("Option --key-file is required.\n"));
+		return -EINVAL;
+	}
+
+	if ((r = crypt_init(&cd, action_argv[1])))
+		goto out;
+
+	r = crypt_format(cd, CRYPT_LOOPAES, NULL, NULL, NULL, NULL,
+			 key_size, &params);
+	if (r < 0)
+		goto out;
+
+	r = crypt_activate_by_keyfile(cd, action_argv[0],
+		CRYPT_ANY_SLOT, opt_key_file, 0,
+		opt_readonly ?  CRYPT_ACTIVATE_READONLY : 0);
+out:
+	crypt_free(cd);
+
+	return r;
+}
+
 static int action_remove(int arg)
 {
 	struct crypt_device *cd = NULL;
@@ -1027,9 +1062,10 @@ int main(int argc, char **argv)
 
 	if (opt_key_size &&
 	   strcmp(aname, "luksFormat") &&
-	   strcmp(aname, "create")) {
+	   strcmp(aname, "create") &&
+	   strcmp(aname, "loopaesOpen")) {
 		usage(popt_context, EXIT_FAILURE,
-		      _("Option --key-size is allowed only for luksFormat and create.\n"
+		      _("Option --key-size is allowed only for luksFormat, create and loopaesOpen.\n"
 		        "To limit read from keyfile use --keyfile-size=(bytes)."),
 		      poptGetInvocationName(popt_context));
 	}