1 files changed, 316 insertions, 0 deletions
diff --git a/lib/luks2/luks2_keyslot_reenc.c b/lib/luks2/luks2_keyslot_reenc.c
new file mode 100644
index 0000000..9da7007
--- /dev/null
+++ b/lib/luks2/luks2_keyslot_reenc.c
@@ -0,0 +1,316 @@
+/*
+ * LUKS - Linux Unified Key Setup v2, reencryption keyslot handler
+ *
+ * Copyright (C) 2016-2021, Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2016-2021, Ondrej Kozina
+ *
+ * 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 "luks2_internal.h"
+
+static int reenc_keyslot_open(struct crypt_device *cd,
+	int keyslot,
+	const char *password,
+	size_t password_len,
+	char *volume_key,
+	size_t volume_key_len)
+{
+	return -ENOENT;
+}
+
+int reenc_keyslot_alloc(struct crypt_device *cd,
+	struct luks2_hdr *hdr,
+	int keyslot,
+	const struct crypt_params_reencrypt *params)
+{
+	int r;
+	json_object *jobj_keyslots, *jobj_keyslot, *jobj_area;
+	uint64_t area_offset, area_length;
+
+	log_dbg(cd, "Allocating reencrypt keyslot %d.", keyslot);
+
+	if (keyslot < 0 || keyslot >= LUKS2_KEYSLOTS_MAX)
+		return -ENOMEM;
+
+	if (!json_object_object_get_ex(hdr->jobj, "keyslots", &jobj_keyslots))
+		return -EINVAL;
+
+	/* encryption doesn't require area (we shift data and backup will be available) */
+	if (!params->data_shift) {
+		r = LUKS2_find_area_max_gap(cd, hdr, &area_offset, &area_length);
+		if (r < 0)
+			return r;
+	} else { /* we can't have keyslot w/o area...bug? */
+		r = LUKS2_find_area_gap(cd, hdr, 1, &area_offset, &area_length);
+		if (r < 0)
+			return r;
+	}
+
+	jobj_keyslot = json_object_new_object();
+	if (!jobj_keyslot)
+		return -ENOMEM;
+
+	jobj_area = json_object_new_object();
+
+	if (params->data_shift) {
+		json_object_object_add(jobj_area, "type", json_object_new_string("datashift"));
+		json_object_object_add(jobj_area, "shift_size", crypt_jobj_new_uint64(params->data_shift << SECTOR_SHIFT));
+	} else
+		/* except data shift protection, initial setting is irrelevant. Type can be changed during reencryption */
+		json_object_object_add(jobj_area, "type", json_object_new_string("none"));
+
+	json_object_object_add(jobj_area, "offset", crypt_jobj_new_uint64(area_offset));
+	json_object_object_add(jobj_area, "size", crypt_jobj_new_uint64(area_length));
+
+	json_object_object_add(jobj_keyslot, "type", json_object_new_string("reencrypt"));
+	json_object_object_add(jobj_keyslot, "key_size", json_object_new_int(1)); /* useless but mandatory */
+	json_object_object_add(jobj_keyslot, "mode", json_object_new_string(crypt_reencrypt_mode_to_str(params->mode)));
+	if (params->direction == CRYPT_REENCRYPT_FORWARD)
+		json_object_object_add(jobj_keyslot, "direction", json_object_new_string("forward"));
+	else if (params->direction == CRYPT_REENCRYPT_BACKWARD)
+		json_object_object_add(jobj_keyslot, "direction", json_object_new_string("backward"));
+	else
+		return -EINVAL;
+
+	json_object_object_add(jobj_keyslot, "area", jobj_area);
+
+	json_object_object_add_by_uint(jobj_keyslots, keyslot, jobj_keyslot);
+	if (LUKS2_check_json_size(cd, hdr)) {
+		log_dbg(cd, "New keyslot too large to fit in free metadata space.");
+		json_object_object_del_by_uint(jobj_keyslots, keyslot);
+		return -ENOSPC;
+	}
+
+	JSON_DBG(cd, hdr->jobj, "JSON:");
+
+	return 0;
+}
+
+static int reenc_keyslot_store_data(struct crypt_device *cd,
+	json_object *jobj_keyslot,
+	const void *buffer, size_t buffer_len)
+{
+	int devfd, r;
+	json_object *jobj_area, *jobj_offset, *jobj_length;
+	uint64_t area_offset, area_length;
+	struct device *device = crypt_metadata_device(cd);
+
+	if (!json_object_object_get_ex(jobj_keyslot, "area", &jobj_area) ||
+	    !json_object_object_get_ex(jobj_area, "offset", &jobj_offset) ||
+	    !json_object_object_get_ex(jobj_area, "size", &jobj_length))
+		return -EINVAL;
+
+	area_offset = crypt_jobj_get_uint64(jobj_offset);
+	area_length = crypt_jobj_get_uint64(jobj_length);
+
+	if (!area_offset || !area_length || ((uint64_t)buffer_len > area_length))
+		return -EINVAL;
+
+	devfd = device_open_locked(cd, device, O_RDWR);
+	if (devfd >= 0) {
+		if (write_lseek_blockwise(devfd, device_block_size(cd, device),
+					  device_alignment(device), CONST_CAST(void *)buffer,
+					  buffer_len, area_offset) < 0)
+			r = -EIO;
+		else
+			r = 0;
+	} else
+		r = -EINVAL;
+
+	if (r)
+		log_err(cd, _("IO error while encrypting keyslot."));
+
+	return r;
+}
+
+static int reenc_keyslot_store(struct crypt_device *cd,
+	int keyslot,
+	const char *password __attribute__((unused)),
+	size_t password_len __attribute__((unused)),
+	const char *buffer,
+	size_t buffer_len)
+{
+	struct luks2_hdr *hdr;
+	json_object *jobj_keyslot;
+	int r = 0;
+
+	if (!cd || !buffer || !buffer_len)
+		return -EINVAL;
+
+	if (!(hdr = crypt_get_hdr(cd, CRYPT_LUKS2)))
+		return -EINVAL;
+
+	log_dbg(cd, "Reencrypt keyslot %d store.", keyslot);
+
+	jobj_keyslot = LUKS2_get_keyslot_jobj(hdr, keyslot);
+	if (!jobj_keyslot)
+		return -EINVAL;
+
+	r = LUKS2_device_write_lock(cd, hdr, crypt_metadata_device(cd));
+	if (r)
+		return r;
+
+	r = reenc_keyslot_store_data(cd, jobj_keyslot, buffer, buffer_len);
+	if (r < 0) {
+		device_write_unlock(cd, crypt_metadata_device(cd));
+		return r;
+	}
+
+	r = LUKS2_hdr_write(cd, hdr);
+
+	device_write_unlock(cd, crypt_metadata_device(cd));
+
+	return r < 0 ? r : keyslot;
+}
+
+static int reenc_keyslot_wipe(struct crypt_device *cd,
+	int keyslot)
+{
+	struct luks2_hdr *hdr;
+
+	if (!(hdr = crypt_get_hdr(cd, CRYPT_LUKS2)))
+		return -EINVAL;
+
+	/* remove reencryption verification data */
+	LUKS2_digest_assign(cd, hdr, keyslot, CRYPT_ANY_DIGEST, 0, 0);
+
+	return 0;
+}
+
+static int reenc_keyslot_dump(struct crypt_device *cd, int keyslot)
+{
+	json_object *jobj_keyslot, *jobj_area, *jobj_direction, *jobj_mode, *jobj_resilience,
+		    *jobj1;
+
+	jobj_keyslot = LUKS2_get_keyslot_jobj(crypt_get_hdr(cd, CRYPT_LUKS2), keyslot);
+	if (!jobj_keyslot)
+		return -EINVAL;
+
+	if (!json_object_object_get_ex(jobj_keyslot, "direction", &jobj_direction) ||
+	    !json_object_object_get_ex(jobj_keyslot, "mode", &jobj_mode) ||
+	    !json_object_object_get_ex(jobj_keyslot, "area", &jobj_area) ||
+	    !json_object_object_get_ex(jobj_area, "type", &jobj_resilience))
+		return -EINVAL;
+
+	log_std(cd, "\t%-12s%s\n", "Mode:", json_object_get_string(jobj_mode));
+	log_std(cd, "\t%-12s%s\n", "Direction:", json_object_get_string(jobj_direction));
+	log_std(cd, "\t%-12s%s\n", "Resilience:", json_object_get_string(jobj_resilience));
+
+	if (!strcmp(json_object_get_string(jobj_resilience), "checksum")) {
+		json_object_object_get_ex(jobj_area, "hash", &jobj1);
+		log_std(cd, "\t%-12s%s\n", "Hash:", json_object_get_string(jobj1));
+		json_object_object_get_ex(jobj_area, "sector_size", &jobj1);
+		log_std(cd, "\t%-12s%d [bytes]\n", "Hash data:", json_object_get_int(jobj1));
+	} else if (!strcmp(json_object_get_string(jobj_resilience), "datashift")) {
+		json_object_object_get_ex(jobj_area, "shift_size", &jobj1);
+		log_std(cd, "\t%-12s%" PRIu64 "[bytes]\n", "Shift size:", crypt_jobj_get_uint64(jobj1));
+	}
+
+	json_object_object_get_ex(jobj_area, "offset", &jobj1);
+	log_std(cd, "\tArea offset:%" PRIu64 " [bytes]\n", crypt_jobj_get_uint64(jobj1));
+
+	json_object_object_get_ex(jobj_area, "size", &jobj1);
+	log_std(cd, "\tArea length:%" PRIu64 " [bytes]\n", crypt_jobj_get_uint64(jobj1));
+
+	return 0;
+}
+
+static int reenc_keyslot_validate(struct crypt_device *cd, json_object *jobj_keyslot)
+{
+	json_object *jobj_mode, *jobj_area, *jobj_type, *jobj_shift_size, *jobj_hash, *jobj_sector_size, *jobj_direction, *jobj_key_size;
+	const char *mode, *type, *direction;
+	uint32_t sector_size;
+	uint64_t shift_size;
+
+	/* mode (string: encrypt,reencrypt,decrypt)
+	 * direction (string:)
+	 * area {
+	 *   type: (string: datashift, journal, checksum, none)
+	 *   	hash: (string: checksum only)
+	 *   	sector_size (uint32: checksum only)
+	 *   	shift_size (uint64: datashift only)
+	 * }
+	 */
+
+	/* area and area type are validated in general validation code */
+	if (!jobj_keyslot || !json_object_object_get_ex(jobj_keyslot, "area", &jobj_area) ||
+	    !json_object_object_get_ex(jobj_area, "type", &jobj_type))
+		return -EINVAL;
+
+	jobj_key_size = json_contains(cd, jobj_keyslot, "", "reencrypt keyslot", "key_size", json_type_int);
+	jobj_mode = json_contains(cd, jobj_keyslot, "", "reencrypt keyslot", "mode", json_type_string);
+	jobj_direction = json_contains(cd, jobj_keyslot, "", "reencrypt keyslot", "direction", json_type_string);
+
+	if (!jobj_mode || !jobj_direction || !jobj_key_size)
+		return -EINVAL;
+
+	if (!validate_json_uint32(jobj_key_size) || crypt_jobj_get_uint32(jobj_key_size) != 1) {
+		log_dbg(cd, "Illegal reencrypt key size.");
+		return -EINVAL;
+	}
+
+	mode = json_object_get_string(jobj_mode);
+	type = json_object_get_string(jobj_type);
+	direction = json_object_get_string(jobj_direction);
+
+	if (strcmp(mode, "reencrypt") && strcmp(mode, "encrypt") &&
+	    strcmp(mode, "decrypt")) {
+		log_dbg(cd, "Illegal reencrypt mode %s.", mode);
+		return -EINVAL;
+	}
+
+	if (strcmp(direction, "forward") && strcmp(direction, "backward")) {
+		log_dbg(cd, "Illegal reencrypt direction %s.", direction);
+		return -EINVAL;
+	}
+
+	if (!strcmp(type, "checksum")) {
+		jobj_hash = json_contains(cd, jobj_area, "type:checksum", "Keyslot area", "hash", json_type_string);
+		jobj_sector_size = json_contains(cd, jobj_area, "type:checksum", "Keyslot area", "sector_size", json_type_int);
+		if (!jobj_hash || !jobj_sector_size)
+			return -EINVAL;
+		if (!validate_json_uint32(jobj_sector_size))
+			return -EINVAL;
+		sector_size = crypt_jobj_get_uint32(jobj_sector_size);
+		if (sector_size < SECTOR_SIZE || NOTPOW2(sector_size)) {
+			log_dbg(cd, "Invalid sector_size (%" PRIu32 ") for checksum resilience mode.", sector_size);
+			return -EINVAL;
+		}
+	} else if (!strcmp(type, "datashift")) {
+		if (!(jobj_shift_size = json_contains(cd, jobj_area, "type:datashift", "Keyslot area", "shift_size", json_type_string)))
+			return -EINVAL;
+
+		shift_size = crypt_jobj_get_uint64(jobj_shift_size);
+		if (!shift_size)
+			return -EINVAL;
+
+		if (MISALIGNED_512(shift_size)) {
+			log_dbg(cd, "Shift size field has to be aligned to sector size: %" PRIu32, SECTOR_SIZE);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+const keyslot_handler reenc_keyslot = {
+	.name  = "reencrypt",
+	.open  = reenc_keyslot_open,
+	.store = reenc_keyslot_store, /* initialization only or also per every chunk write */
+	.wipe  = reenc_keyslot_wipe,
+	.dump  = reenc_keyslot_dump,
+	.validate  = reenc_keyslot_validate
+};