1 files changed, 497 insertions, 0 deletions
diff --git a/src/libdnssec/keystore/pkcs8.c b/src/libdnssec/keystore/pkcs8.c
new file mode 100644
index 0000000..047bde8
--- /dev/null
+++ b/src/libdnssec/keystore/pkcs8.c
@@ -0,0 +1,497 @@
+/*  Copyright (C) 2022 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    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 3 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, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <assert.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include "contrib/files.h"
+#include "libdnssec/binary.h"
+#include "libdnssec/error.h"
+#include "libdnssec/keystore.h"
+#include "libdnssec/keystore/internal.h"
+#include "libdnssec/pem.h"
+#include "libdnssec/shared/shared.h"
+#include "libdnssec/shared/keyid_gnutls.h"
+
+#define DIR_INIT_MODE 0750
+
+/*!
+ * Context for PKCS #8 key directory.
+ */
+typedef struct {
+	char *dir_name;
+} pkcs8_dir_handle_t;
+
+/* -- internal functions --------------------------------------------------- */
+
+/*!
+ * Get path to a private key in PKCS #8 PEM format.
+ */
+static char *key_path(const char *dir, const char *id)
+{
+	char *strp = NULL;
+
+	int ret = asprintf(&strp, "%s/%s.pem", dir, id);
+	if (ret < 0) {
+		return NULL;
+	}
+	return strp;
+}
+
+/*!
+ * Get size of the file and reset the position to the beginning of the file.
+ */
+static int file_size(int fd, size_t *size)
+{
+	off_t offset = lseek(fd, 0, SEEK_END);
+	if (offset == -1) {
+		return dnssec_errno_to_error(errno);
+	}
+
+	if (lseek(fd, 0, SEEK_SET) == -1) {
+		return dnssec_errno_to_error(errno);
+	}
+
+	assert(offset >= 0);
+	*size = offset;
+
+	return DNSSEC_EOK;
+}
+
+/*!
+ * Open a key file and get the descriptor.
+ */
+static int key_open(const char *dir_name, const char *id, int flags,
+		    mode_t mode, int *fd_ptr)
+{
+	assert(dir_name);
+	assert(id);
+	assert(fd_ptr);
+
+	_cleanup_free_ char *filename = key_path(dir_name, id);
+	if (!filename) {
+		return DNSSEC_ENOMEM;
+	}
+
+	int fd = open(filename, flags, mode);
+	if (fd == -1) {
+		return dnssec_errno_to_error(errno);
+	}
+
+	*fd_ptr = fd;
+
+	return DNSSEC_EOK;
+}
+
+static int key_open_read(const char *dir_name, const char *id, int *fd_ptr)
+{
+	return key_open(dir_name, id, O_RDONLY, 0, fd_ptr);
+}
+
+static int key_open_write(const char *dir_name, const char *id, int *fd_ptr)
+{
+	return key_open(dir_name, id, O_WRONLY|O_CREAT|O_EXCL,
+			S_IRUSR|S_IWUSR|S_IRGRP, fd_ptr);
+}
+
+static int pkcs8_dir_read(pkcs8_dir_handle_t *handle, const char *id, dnssec_binary_t *pem)
+{
+	if (!handle || !id || !pem) {
+		return DNSSEC_EINVAL;
+	}
+
+	// open file and get it's size
+
+	_cleanup_close_ int file = -1;
+	int result = key_open_read(handle->dir_name, id, &file);
+	if (result != DNSSEC_EOK) {
+		return result;
+	}
+
+	size_t size = 0;
+	result = file_size(file, &size);
+	if (result != DNSSEC_EOK) {
+		return result;
+	}
+
+	if (size == 0) {
+		return DNSSEC_MALFORMED_DATA;
+	}
+
+	// read the stored data
+
+	dnssec_binary_t read_pem = { 0 };
+	result = dnssec_binary_alloc(&read_pem, size);
+	if (result != DNSSEC_EOK) {
+		return result;
+	}
+
+	ssize_t read_count = read(file, read_pem.data, read_pem.size);
+	if (read_count == -1) {
+		dnssec_binary_free(&read_pem);
+		return dnssec_errno_to_error(errno);
+	}
+
+	assert(read_count == read_pem.size);
+	*pem = read_pem;
+
+	return DNSSEC_EOK;
+}
+
+static bool key_is_duplicate(int open_error, pkcs8_dir_handle_t *handle,
+			     const char *id, const dnssec_binary_t *pem)
+{
+	assert(handle);
+	assert(id);
+	assert(pem);
+
+	if (open_error != dnssec_errno_to_error(EEXIST)) {
+		return false;
+	}
+
+	_cleanup_binary_ dnssec_binary_t old = { 0 };
+	int r = pkcs8_dir_read(handle, id, &old);
+	if (r != DNSSEC_EOK) {
+		return false;
+	}
+
+	return dnssec_binary_cmp(&old, pem) == 0;
+}
+
+static int pem_generate(gnutls_pk_algorithm_t algorithm, unsigned bits,
+			dnssec_binary_t *pem, char **id)
+{
+	assert(pem);
+	assert(id);
+
+	// generate key
+
+	_cleanup_x509_privkey_ gnutls_x509_privkey_t key = NULL;
+	int r = gnutls_x509_privkey_init(&key);
+	if (r != GNUTLS_E_SUCCESS) {
+		return DNSSEC_ENOMEM;
+	}
+
+	r = gnutls_x509_privkey_generate(key, algorithm, bits, 0);
+	if (r != GNUTLS_E_SUCCESS) {
+		return DNSSEC_KEY_GENERATE_ERROR;
+	}
+
+	// convert to PEM and export the ID
+
+	dnssec_binary_t _pem = { 0 };
+	r = dnssec_pem_from_x509(key, &_pem);
+	if (r != DNSSEC_EOK) {
+		return r;
+	}
+
+	// export key ID
+
+	char *_id = NULL;
+	r = keyid_x509_hex(key, &_id);
+	if (r != DNSSEC_EOK) {
+		dnssec_binary_free(&_pem);
+		return r;
+	}
+
+	*id = _id;
+	*pem = _pem;
+
+	return DNSSEC_EOK;
+}
+
+/* -- internal API --------------------------------------------------------- */
+
+static int pkcs8_ctx_new(void **ctx_ptr)
+{
+	if (!ctx_ptr) {
+		return DNSSEC_EINVAL;
+	}
+
+	pkcs8_dir_handle_t *ctx = calloc(1, sizeof(*ctx));
+	if (!ctx) {
+		return DNSSEC_ENOMEM;
+	}
+
+	*ctx_ptr = ctx;
+
+	return DNSSEC_EOK;
+}
+
+static void pkcs8_ctx_free(void *ctx)
+{
+	free(ctx);
+}
+
+static int pkcs8_init(void *ctx, const char *config)
+{
+	if (!ctx || !config) {
+		return DNSSEC_EINVAL;
+	}
+
+	return make_dir(config, DIR_INIT_MODE, true);
+}
+
+static int pkcs8_open(void *ctx, const char *config)
+{
+	if (!ctx || !config) {
+		return DNSSEC_EINVAL;
+	}
+
+	pkcs8_dir_handle_t *handle = ctx;
+
+	char *path = realpath(config, NULL);
+	if (!path) {
+		return DNSSEC_NOT_FOUND;
+	}
+
+	handle->dir_name = path;
+
+	return DNSSEC_EOK;
+}
+
+static int pkcs8_close(void *ctx)
+{
+	if (!ctx) {
+		return DNSSEC_EINVAL;
+	}
+
+	pkcs8_dir_handle_t *handle = ctx;
+
+	free(handle->dir_name);
+	memset(handle, 0, sizeof(*handle));
+
+	return DNSSEC_EOK;
+}
+
+static int pkcs8_generate_key(void *ctx, gnutls_pk_algorithm_t algorithm,
+			      unsigned bits, const char *label, char **id_ptr)
+{
+	if (!ctx || !id_ptr) {
+		return DNSSEC_EINVAL;
+	}
+
+	(void)label;
+
+	pkcs8_dir_handle_t *handle = ctx;
+
+	// generate key
+
+	char *id = NULL;
+	_cleanup_binary_ dnssec_binary_t pem = { 0 };
+	int r = pem_generate(algorithm, bits, &pem, &id);
+	if (r != DNSSEC_EOK) {
+		return r;
+	}
+
+	// create the file
+
+	_cleanup_close_ int file = -1;
+	r = key_open_write(handle->dir_name, id, &file);
+	if (r != DNSSEC_EOK) {
+		if (key_is_duplicate(r, handle, id, &pem)) {
+			return DNSSEC_EOK;
+		}
+		return r;
+	}
+
+	// write the data
+
+	ssize_t wrote_count = write(file, pem.data, pem.size);
+	if (wrote_count == -1) {
+		return dnssec_errno_to_error(errno);
+	}
+
+	assert(wrote_count == pem.size);
+
+	// finish
+
+	*id_ptr = id;
+
+	return DNSSEC_EOK;
+}
+
+static int pkcs8_import_key(void *ctx, const dnssec_binary_t *pem, char **id_ptr)
+{
+	if (!ctx || !pem || !id_ptr) {
+		return DNSSEC_EINVAL;
+	}
+
+	pkcs8_dir_handle_t *handle = ctx;
+
+	// retrieve key ID
+
+	char *id = NULL;
+	_cleanup_x509_privkey_ gnutls_x509_privkey_t key = NULL;
+	int r = dnssec_pem_to_x509(pem, &key);
+	if (r != DNSSEC_EOK) {
+		return r;
+	}
+
+	r = keyid_x509_hex(key, &id);
+	if (r != DNSSEC_EOK) {
+		return r;
+	}
+
+	// create the file
+
+	_cleanup_close_ int file = -1;
+	r = key_open_write(handle->dir_name, id, &file);
+	if (r != DNSSEC_EOK) {
+		if (key_is_duplicate(r, handle, id, pem)) {
+			*id_ptr = id;
+			return DNSSEC_EOK;
+		}
+		free(id);
+		return r;
+	}
+
+	// write the data
+
+	ssize_t wrote_count = write(file, pem->data, pem->size);
+	if (wrote_count == -1) {
+		free(id);
+		return dnssec_errno_to_error(errno);
+	}
+
+	assert(wrote_count == pem->size);
+
+	// finish
+
+	*id_ptr = id;
+
+	return DNSSEC_EOK;
+}
+
+static int pkcs8_remove_key(void *ctx, const char *id)
+{
+	if (!ctx || !id) {
+		return DNSSEC_EINVAL;
+	}
+
+	pkcs8_dir_handle_t *handle = ctx;
+
+	_cleanup_free_ char *filename = key_path(handle->dir_name, id);
+	if (!filename) {
+		return DNSSEC_ENOMEM;
+	}
+
+	if (unlink(filename) == -1) {
+		return dnssec_errno_to_error(errno);
+	}
+
+	return DNSSEC_EOK;
+}
+
+static int pkcs8_get_private(void *ctx, const char *id, gnutls_privkey_t *key_ptr)
+{
+	if (!ctx || !id || !key_ptr) {
+		return DNSSEC_EINVAL;
+	}
+
+	pkcs8_dir_handle_t *handle = ctx;
+
+	// load private key data
+
+	_cleanup_close_ int file = -1;
+	int r = key_open_read(handle->dir_name, id, &file);
+	if (r != DNSSEC_EOK) {
+		return r;
+	}
+
+	size_t size = 0;
+	r = file_size(file, &size);
+	if (r != DNSSEC_EOK) {
+		return r;
+	}
+
+	if (size == 0) {
+		return DNSSEC_MALFORMED_DATA;
+	}
+
+	// read the stored data
+
+	_cleanup_binary_ dnssec_binary_t pem = { 0 };
+	r = dnssec_binary_alloc(&pem, size);
+	if (r != DNSSEC_EOK) {
+		return r;
+	}
+
+	ssize_t read_count = read(file, pem.data, pem.size);
+	if (read_count == -1) {
+		dnssec_binary_free(&pem);
+		return dnssec_errno_to_error(errno);
+	}
+
+	assert(read_count == pem.size);
+
+	// construct the key
+
+	gnutls_privkey_t key = NULL;
+	r = dnssec_pem_to_privkey(&pem, &key);
+	if (r != DNSSEC_EOK) {
+		return r;
+	}
+
+	// finish
+
+	*key_ptr = key;
+
+	return DNSSEC_EOK;
+}
+
+static int pkcs8_set_private(void *ctx, gnutls_privkey_t key)
+{
+	if (!ctx) {
+		return DNSSEC_EINVAL;
+	}
+
+	_cleanup_binary_ dnssec_binary_t pem = { 0 };
+	int r = dnssec_pem_from_privkey(key, &pem);
+	if (r != DNSSEC_EOK) {
+		return r;
+	}
+
+	_cleanup_free_ char *keyid = NULL;
+
+	return pkcs8_import_key(ctx, &pem, &keyid);
+}
+
+/* -- public API ----------------------------------------------------------- */
+
+_public_
+int dnssec_keystore_init_pkcs8(dnssec_keystore_t **store_ptr)
+{
+	static const keystore_functions_t IMPLEMENTATION = {
+		.ctx_new      = pkcs8_ctx_new,
+		.ctx_free     = pkcs8_ctx_free,
+		.init         = pkcs8_init,
+		.open         = pkcs8_open,
+		.close        = pkcs8_close,
+		.generate_key = pkcs8_generate_key,
+		.import_key   = pkcs8_import_key,
+		.remove_key   = pkcs8_remove_key,
+		.get_private  = pkcs8_get_private,
+		.set_private  = pkcs8_set_private,
+	};
+
+	return keystore_create(store_ptr, &IMPLEMENTATION);
+}