1 files changed, 333 insertions, 0 deletions
diff --git a/lib/utils_pbkdf.c b/lib/utils_pbkdf.c
new file mode 100644
index 0000000..575d841
--- /dev/null
+++ b/lib/utils_pbkdf.c
@@ -0,0 +1,333 @@
+/*
+ * utils_pbkdf - PBKDF settings for libcryptsetup
+ *
+ * Copyright (C) 2009-2021 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2009-2021 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 <errno.h>
+
+#include "internal.h"
+
+const struct crypt_pbkdf_type default_pbkdf2 = {
+	.type = CRYPT_KDF_PBKDF2,
+	.hash = DEFAULT_LUKS1_HASH,
+	.time_ms = DEFAULT_LUKS1_ITER_TIME
+};
+
+const struct crypt_pbkdf_type default_argon2i = {
+	.type = CRYPT_KDF_ARGON2I,
+	.hash = DEFAULT_LUKS1_HASH,
+	.time_ms = DEFAULT_LUKS2_ITER_TIME,
+	.max_memory_kb = DEFAULT_LUKS2_MEMORY_KB,
+	.parallel_threads = DEFAULT_LUKS2_PARALLEL_THREADS
+};
+
+const struct crypt_pbkdf_type default_argon2id = {
+	.type = CRYPT_KDF_ARGON2ID,
+	.hash = DEFAULT_LUKS1_HASH,
+	.time_ms = DEFAULT_LUKS2_ITER_TIME,
+	.max_memory_kb = DEFAULT_LUKS2_MEMORY_KB,
+	.parallel_threads = DEFAULT_LUKS2_PARALLEL_THREADS
+};
+
+const struct crypt_pbkdf_type *crypt_get_pbkdf_type_params(const char *pbkdf_type)
+{
+	if (!pbkdf_type)
+		return NULL;
+
+	if (!strcmp(pbkdf_type, CRYPT_KDF_PBKDF2))
+		return &default_pbkdf2;
+	else if (!strcmp(pbkdf_type, CRYPT_KDF_ARGON2I))
+		return &default_argon2i;
+	else if (!strcmp(pbkdf_type, CRYPT_KDF_ARGON2ID))
+		return &default_argon2id;
+
+	return NULL;
+}
+
+static uint32_t adjusted_phys_memory(void)
+{
+	uint64_t memory_kb = crypt_getphysmemory_kb();
+
+	/* Ignore bogus value */
+	if (memory_kb < (128 * 1024) || memory_kb > UINT32_MAX)
+		return DEFAULT_LUKS2_MEMORY_KB;
+
+	/*
+	 * Never use more than half of physical memory.
+	 * OOM killer is too clever...
+	 */
+	memory_kb /= 2;
+
+	return memory_kb;
+}
+
+/*
+ * PBKDF configuration interface
+ */
+int verify_pbkdf_params(struct crypt_device *cd,
+			const struct crypt_pbkdf_type *pbkdf)
+{
+	struct crypt_pbkdf_limits pbkdf_limits;
+	const char *pbkdf_type;
+	int r;
+
+	r = init_crypto(cd);
+	if (r < 0)
+		return r;
+
+	if (!pbkdf->type ||
+	    (!pbkdf->hash && !strcmp(pbkdf->type, "pbkdf2")))
+		return -EINVAL;
+
+	if (!pbkdf->time_ms && !(pbkdf->flags & CRYPT_PBKDF_NO_BENCHMARK)) {
+		log_err(cd, _("Requested PBKDF target time cannot be zero."));
+		return -EINVAL;
+	}
+
+	r = crypt_parse_pbkdf(pbkdf->type, &pbkdf_type);
+	if (r < 0) {
+		log_err(cd, _("Unknown PBKDF type %s."), pbkdf->type);
+		return r;
+	}
+
+	if (pbkdf->hash && crypt_hash_size(pbkdf->hash) < 0) {
+		log_err(cd, _("Requested hash %s is not supported."), pbkdf->hash);
+		return -EINVAL;
+	}
+
+	r = crypt_pbkdf_get_limits(pbkdf->type, &pbkdf_limits);
+	if (r < 0)
+		return r;
+
+	if (crypt_get_type(cd) &&
+	    !strcmp(crypt_get_type(cd), CRYPT_LUKS1) &&
+	    strcmp(pbkdf_type, CRYPT_KDF_PBKDF2)) {
+		log_err(cd, _("Requested PBKDF type is not supported for LUKS1."));
+		return -EINVAL;
+	}
+
+	if (!strcmp(pbkdf_type, CRYPT_KDF_PBKDF2)) {
+		if (pbkdf->max_memory_kb || pbkdf->parallel_threads) {
+			log_err(cd, _("PBKDF max memory or parallel threads must not be set with pbkdf2."));
+			return -EINVAL;
+		}
+		if (pbkdf->flags & CRYPT_PBKDF_NO_BENCHMARK &&
+		    pbkdf->iterations < pbkdf_limits.min_iterations) {
+			log_err(cd, _("Forced iteration count is too low for %s (minimum is %u)."),
+				pbkdf_type, pbkdf_limits.min_iterations);
+			return -EINVAL;
+		}
+		return 0;
+	}
+
+	/* TODO: properly define minimal iterations and also minimal memory values */
+	if (pbkdf->flags & CRYPT_PBKDF_NO_BENCHMARK) {
+		if (pbkdf->iterations < pbkdf_limits.min_iterations) {
+			log_err(cd, _("Forced iteration count is too low for %s (minimum is %u)."),
+				pbkdf_type, pbkdf_limits.min_iterations);
+			r = -EINVAL;
+		}
+		if (pbkdf->max_memory_kb < pbkdf_limits.min_memory) {
+			log_err(cd, _("Forced memory cost is too low for %s (minimum is %u kilobytes)."),
+				pbkdf_type, pbkdf_limits.min_memory);
+			r = -EINVAL;
+		}
+	}
+
+	if (pbkdf->max_memory_kb > pbkdf_limits.max_memory) {
+		log_err(cd, _("Requested maximum PBKDF memory cost is too high (maximum is %d kilobytes)."),
+			pbkdf_limits.max_memory);
+		r = -EINVAL;
+	}
+	if (!pbkdf->max_memory_kb) {
+		log_err(cd, _("Requested maximum PBKDF memory cannot be zero."));
+		r = -EINVAL;
+	}
+	if (!pbkdf->parallel_threads) {
+		log_err(cd, _("Requested PBKDF parallel threads cannot be zero."));
+		r = -EINVAL;
+	}
+
+	return r;
+}
+
+int init_pbkdf_type(struct crypt_device *cd,
+		    const struct crypt_pbkdf_type *pbkdf,
+		    const char *dev_type)
+{
+	struct crypt_pbkdf_type *cd_pbkdf = crypt_get_pbkdf(cd);
+	struct crypt_pbkdf_limits pbkdf_limits;
+	const char *hash, *type;
+	unsigned cpus;
+	uint32_t old_flags, memory_kb;
+	int r;
+
+	if (crypt_fips_mode()) {
+		if (pbkdf && strcmp(pbkdf->type, CRYPT_KDF_PBKDF2)) {
+			log_err(cd, _("Only PBKDF2 is supported in FIPS mode."));
+			return -EINVAL;
+		}
+		if (!pbkdf)
+			pbkdf = crypt_get_pbkdf_type_params(CRYPT_KDF_PBKDF2);
+	}
+
+	if (!pbkdf && dev_type && !strcmp(dev_type, CRYPT_LUKS2))
+		pbkdf = crypt_get_pbkdf_type_params(DEFAULT_LUKS2_PBKDF);
+	else if (!pbkdf)
+		pbkdf = crypt_get_pbkdf_type_params(CRYPT_KDF_PBKDF2);
+
+	r = verify_pbkdf_params(cd, pbkdf);
+	if (r)
+		return r;
+
+	r = crypt_pbkdf_get_limits(pbkdf->type, &pbkdf_limits);
+	if (r < 0)
+		return r;
+
+	type = strdup(pbkdf->type);
+	hash = pbkdf->hash ? strdup(pbkdf->hash) : NULL;
+
+	if (!type || (!hash && pbkdf->hash)) {
+		free(CONST_CAST(void*)type);
+		free(CONST_CAST(void*)hash);
+		return -ENOMEM;
+	}
+
+	free(CONST_CAST(void*)cd_pbkdf->type);
+	free(CONST_CAST(void*)cd_pbkdf->hash);
+	cd_pbkdf->type = type;
+	cd_pbkdf->hash = hash;
+
+	old_flags = cd_pbkdf->flags;
+	cd_pbkdf->flags = pbkdf->flags;
+
+	/* Reset iteration count so benchmark must run again. */
+	if (cd_pbkdf->flags & CRYPT_PBKDF_NO_BENCHMARK)
+		cd_pbkdf->iterations = pbkdf->iterations;
+	else
+		cd_pbkdf->iterations = 0;
+
+	if (old_flags & CRYPT_PBKDF_ITER_TIME_SET)
+		cd_pbkdf->flags |= CRYPT_PBKDF_ITER_TIME_SET;
+	else
+		cd_pbkdf->time_ms = pbkdf->time_ms;
+
+	cd_pbkdf->max_memory_kb = pbkdf->max_memory_kb;
+	cd_pbkdf->parallel_threads = pbkdf->parallel_threads;
+
+	if (cd_pbkdf->parallel_threads > pbkdf_limits.max_parallel) {
+		log_dbg(cd, "Maximum PBKDF threads is %d (requested %d).",
+			pbkdf_limits.max_parallel, cd_pbkdf->parallel_threads);
+		cd_pbkdf->parallel_threads = pbkdf_limits.max_parallel;
+	}
+
+	if (cd_pbkdf->parallel_threads) {
+		cpus = crypt_cpusonline();
+		if (cd_pbkdf->parallel_threads > cpus) {
+			log_dbg(cd, "Only %u active CPUs detected, "
+				"PBKDF threads decreased from %d to %d.",
+				cpus, cd_pbkdf->parallel_threads, cpus);
+			cd_pbkdf->parallel_threads = cpus;
+		}
+	}
+
+	if (cd_pbkdf->max_memory_kb) {
+		memory_kb = adjusted_phys_memory();
+		if (cd_pbkdf->max_memory_kb > memory_kb) {
+			log_dbg(cd, "Not enough physical memory detected, "
+				"PBKDF max memory decreased from %dkB to %dkB.",
+				cd_pbkdf->max_memory_kb, memory_kb);
+			cd_pbkdf->max_memory_kb = memory_kb;
+		}
+	}
+
+	if (!strcmp(pbkdf->type, CRYPT_KDF_PBKDF2))
+		log_dbg(cd, "PBKDF %s-%s, time_ms %u (iterations %u).",
+			cd_pbkdf->type, cd_pbkdf->hash, cd_pbkdf->time_ms, cd_pbkdf->iterations);
+	else
+		log_dbg(cd, "PBKDF %s, time_ms %u (iterations %u), max_memory_kb %u, parallel_threads %u.",
+			cd_pbkdf->type, cd_pbkdf->time_ms, cd_pbkdf->iterations,
+			cd_pbkdf->max_memory_kb, cd_pbkdf->parallel_threads);
+
+	return 0;
+}
+
+/* Libcryptsetup API */
+
+int crypt_set_pbkdf_type(struct crypt_device *cd, const struct crypt_pbkdf_type *pbkdf)
+{
+	if (!cd)
+		return -EINVAL;
+
+	if (!pbkdf)
+		log_dbg(cd, "Resetting pbkdf type to default");
+
+	crypt_get_pbkdf(cd)->flags = 0;
+
+	return init_pbkdf_type(cd, pbkdf, crypt_get_type(cd));
+}
+
+const struct crypt_pbkdf_type *crypt_get_pbkdf_type(struct crypt_device *cd)
+{
+	if (!cd)
+		return NULL;
+
+	return crypt_get_pbkdf(cd)->type ? crypt_get_pbkdf(cd) : NULL;
+}
+
+const struct crypt_pbkdf_type *crypt_get_pbkdf_default(const char *type)
+{
+	if (!type)
+		return NULL;
+
+	if (!strcmp(type, CRYPT_LUKS1) || crypt_fips_mode())
+		return crypt_get_pbkdf_type_params(CRYPT_KDF_PBKDF2);
+	else if (!strcmp(type, CRYPT_LUKS2))
+		return crypt_get_pbkdf_type_params(DEFAULT_LUKS2_PBKDF);
+
+	return NULL;
+}
+
+void crypt_set_iteration_time(struct crypt_device *cd, uint64_t iteration_time_ms)
+{
+	struct crypt_pbkdf_type *pbkdf;
+	uint32_t old_time_ms;
+
+	if (!cd || iteration_time_ms > UINT32_MAX)
+		return;
+
+	pbkdf = crypt_get_pbkdf(cd);
+	old_time_ms = pbkdf->time_ms;
+	pbkdf->time_ms = (uint32_t)iteration_time_ms;
+
+	if (pbkdf->type && verify_pbkdf_params(cd, pbkdf)) {
+		pbkdf->time_ms = old_time_ms;
+		log_dbg(cd, "Invalid iteration time.");
+		return;
+	}
+
+	pbkdf->flags |= CRYPT_PBKDF_ITER_TIME_SET;
+
+	/* iterations must be benchmarked now */
+	pbkdf->flags &= ~(CRYPT_PBKDF_NO_BENCHMARK);
+	pbkdf->iterations = 0;
+
+	log_dbg(cd, "Iteration time set to %" PRIu64 " milliseconds.", iteration_time_ms);
+}