Adding upstream version 2.7.6.upstream/2.7.6upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

14 files changed, 1183 insertions, 0 deletions

diff --git a/src/libdnssec/shared/bignum.c b/src/libdnssec/shared/bignum.c
new file mode 100644
index 0000000..921a1e6
--- /dev/null
+++ b/src/libdnssec/shared/bignum.c
@@ -0,0 +1,64 @@
+/*  Copyright (C) 2018 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 <http://www.gnu.org/licenses/>.
+*/
+
+#include <assert.h>
+#include <string.h>
+
+#include "libdnssec/shared/bignum.h"
+
+static void skip_leading_zeroes(dnssec_binary_t *value)
+{
+	while (value->size > 0 && value->data[0] == 0) {
+		value->data += 1;
+		value->size -= 1;
+	}
+}
+
+size_t bignum_size_u(const dnssec_binary_t *_value)
+{
+	dnssec_binary_t value = *_value;
+	skip_leading_zeroes(&value);
+
+	if (value.size == 0) {
+		return value.size + 1;
+	} else {
+		return value.size;
+	}
+}
+
+size_t bignum_size_s(const dnssec_binary_t *_value)
+{
+	dnssec_binary_t value = *_value;
+	skip_leading_zeroes(&value);
+
+	if (value.size == 0 || value.data[0] & 0x80) {
+		return value.size + 1;
+	} else {
+		return value.size;
+	}
+}
+
+void bignum_write(wire_ctx_t *ctx, size_t width, const dnssec_binary_t *_value)
+{
+	dnssec_binary_t value = *_value;
+	skip_leading_zeroes(&value);
+
+	size_t padding_len = width - value.size;
+	if (padding_len > 0) {
+		wire_ctx_clear(ctx, padding_len);
+	}
+	wire_ctx_write(ctx, value.data, value.size);
+}
diff --git a/src/libdnssec/shared/bignum.h b/src/libdnssec/shared/bignum.h
new file mode 100644
index 0000000..4186a63
--- /dev/null
+++ b/src/libdnssec/shared/bignum.h
@@ -0,0 +1,41 @@
+/*  Copyright (C) 2018 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 <http://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#include <stdlib.h>
+
+#include "libdnssec/binary.h"
+#include "contrib/wire_ctx.h"
+
+/*!
+ * Size needed to write unsigned number in unsigned encoding.
+ */
+size_t bignum_size_u(const dnssec_binary_t *value);
+
+/*!
+ * Size needed to write unsigned number in signed encoding.
+ *
+ * Signed encoding expects the MSB to be zero.
+ */
+size_t bignum_size_s(const dnssec_binary_t *value);
+
+/*!
+ * Write unsigned number on a fixed width in a big-endian byte order.
+ *
+ * The destination size has to be set properly to accommodate used encoding.
+ */
+void bignum_write(wire_ctx_t *ctx, size_t width, const dnssec_binary_t *value);
diff --git a/src/libdnssec/shared/binary_wire.h b/src/libdnssec/shared/binary_wire.h
new file mode 100644
index 0000000..78ccff0
--- /dev/null
+++ b/src/libdnssec/shared/binary_wire.h
@@ -0,0 +1,53 @@
+/*  Copyright (C) 2018 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 <http://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#include <stdlib.h>
+
+#include "contrib/wire_ctx.h"
+#include "libdnssec/binary.h"
+
+static inline wire_ctx_t binary_init(const dnssec_binary_t *binary)
+{
+	assert(binary);
+
+	return wire_ctx_init(binary->data, binary->size);
+}
+
+static inline void binary_read(wire_ctx_t *ctx, dnssec_binary_t *data)
+{
+	assert(data);
+
+	wire_ctx_read(ctx, data->data, data->size);
+}
+
+static inline void binary_available(wire_ctx_t *ctx, dnssec_binary_t *data)
+{
+	assert(ctx);
+	assert(data);
+
+	data->data = ctx->position;
+	data->size = wire_ctx_available(ctx);
+}
+
+static inline void binary_write(wire_ctx_t *ctx, const dnssec_binary_t *data)
+{
+	assert(ctx);
+	assert(data);
+
+	wire_ctx_write(ctx, data->data, data->size);
+}
diff --git a/src/libdnssec/shared/dname.c b/src/libdnssec/shared/dname.c
new file mode 100644
index 0000000..51605f6
--- /dev/null
+++ b/src/libdnssec/shared/dname.c
@@ -0,0 +1,165 @@
+/*  Copyright (C) 2018 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 <http://www.gnu.org/licenses/>.
+*/
+
+#include <assert.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+
+#include "libdnssec/shared/dname.h"
+#include "libdnssec/shared/shared.h"
+#include "contrib/tolower.h"
+
+/*!
+ * Get length of a domain name in wire format.
+ */
+size_t dname_length(const uint8_t *dname)
+{
+	if (!dname) {
+		return 0;
+	}
+
+	const uint8_t *scan = dname;
+	uint8_t label_len;
+	do {
+		label_len = *scan;
+		scan += 1 + label_len;
+	} while (label_len > 0);
+	assert(scan > dname);
+
+	size_t length = scan - dname;
+	if (length > DNAME_MAX_LENGTH) {
+		return 0;
+	}
+
+	return length;
+}
+
+/*!
+ * Copy domain name in wire format.
+ */
+uint8_t *dname_copy(const uint8_t *dname)
+{
+	if (!dname) {
+		return NULL;
+	}
+
+	size_t length = dname_length(dname);
+	if (length == 0) {
+		return NULL;
+	}
+
+	uint8_t *copy = malloc(length);
+	if (!copy) {
+		return NULL;
+	}
+
+	memmove(copy, dname, length);
+	return copy;
+}
+
+/*!
+ * Normalize dname label in-place.
+ *
+ * \return Number of processed bytes, 0 if we encounter the last label.
+ */
+static uint8_t normalize_label(uint8_t *label)
+{
+	assert(label);
+
+	uint8_t len = *label;
+	if (len == 0 || len > DNAME_MAX_LABEL_LENGTH) {
+		return 0;
+	}
+
+	for (uint8_t *scan = label + 1, *end = scan + len; scan < end; scan++) {
+		*scan = knot_tolower(*scan);
+	}
+
+	return len + 1;
+}
+
+/*!
+ * Normalize domain name in wire format.
+ */
+void dname_normalize(uint8_t *dname)
+{
+	if (!dname) {
+		return;
+	}
+
+	uint8_t read, *scan = dname;
+	do {
+		read = normalize_label(scan);
+		scan += read;
+	} while (read > 0);
+}
+
+/*!
+ * Compare dname labels case insensitively.
+ */
+static int label_casecmp(const uint8_t *a, const uint8_t *b, uint8_t len)
+{
+	assert(a);
+	assert(b);
+
+	for (const uint8_t *a_end = a + len; a < a_end; a++, b++) {
+		if (knot_tolower(*a) != knot_tolower(*b)) {
+			return false;
+		}
+	}
+
+	return true;
+}
+
+/*!
+ * Check if two dnames are equal.
+ */
+bool dname_equal(const uint8_t *one, const uint8_t *two)
+{
+	if (!one || !two) {
+		return false;
+	}
+
+	const uint8_t *scan_one = one;
+	const uint8_t *scan_two = two;
+
+	for (;;) {
+		if (*scan_one != *scan_two) {
+			return false;
+		}
+
+		uint8_t len = *scan_one;
+		if (len == 0) {
+			return true;
+		} else if (len > DNAME_MAX_LABEL_LENGTH) {
+			return false;
+		}
+
+		scan_one += 1;
+		scan_two += 1;
+
+		if (!label_casecmp(scan_one, scan_two, len)) {
+			return false;
+		}
+
+		scan_one += len;
+		scan_two += len;
+	}
+
+	return true;
+}
diff --git a/src/libdnssec/shared/dname.h b/src/libdnssec/shared/dname.h
new file mode 100644
index 0000000..82adeb7
--- /dev/null
+++ b/src/libdnssec/shared/dname.h
@@ -0,0 +1,57 @@
+/*  Copyright (C) 2018 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 <http://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+/*!
+ * Maximal length of domain name including labels and length bytes.
+ * \see RFC 1035
+ */
+#define DNAME_MAX_LENGTH 255
+
+/*!
+ * Maximal length of the domain name label, excluding the label size.
+ * \see RFC 1035
+ */
+#define DNAME_MAX_LABEL_LENGTH 63
+
+/*!
+ * Get length of a domain name in wire format.
+ */
+size_t dname_length(const uint8_t *dname);
+
+/*!
+ * Copy domain name in wire format.
+ */
+uint8_t *dname_copy(const uint8_t *dname);
+
+/*!
+ * Normalize domain name in wire format.
+ *
+ * Currently converts all letters to lowercase.
+ */
+void dname_normalize(uint8_t *dname);
+
+/*!
+ * Check if two dnames are equal.
+ *
+ * Case insensitive.
+ */
+bool dname_equal(const uint8_t *one, const uint8_t *two);
diff --git a/src/libdnssec/shared/fs.c b/src/libdnssec/shared/fs.c
new file mode 100644
index 0000000..10c25d9
--- /dev/null
+++ b/src/libdnssec/shared/fs.c
@@ -0,0 +1,47 @@
+/*  Copyright (C) 2018 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 <http://www.gnu.org/licenses/>.
+*/
+
+#include <assert.h>
+#include <stdbool.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "libdnssec/error.h"
+
+int fs_mkdir(const char *path, mode_t mode, bool ignore_existing)
+{
+	if (mkdir(path, mode) == 0) {
+		return DNSSEC_EOK;
+	}
+
+	if (!ignore_existing || errno != EEXIST) {
+		return dnssec_errno_to_error(errno);
+	}
+
+	assert(errno == EEXIST);
+
+	struct stat st = { 0 };
+	if (stat(path, &st) != 0) {
+		return dnssec_errno_to_error(errno);
+	}
+
+	if (!S_ISDIR(st.st_mode)) {
+		return dnssec_errno_to_error(ENOTDIR);
+	}
+
+	return DNSSEC_EOK;
+}
diff --git a/src/libdnssec/shared/fs.h b/src/libdnssec/shared/fs.h
new file mode 100644
index 0000000..542c87b
--- /dev/null
+++ b/src/libdnssec/shared/fs.h
@@ -0,0 +1,25 @@
+/*  Copyright (C) 2018 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 <http://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#include <stdbool.h>
+#include <sys/types.h>
+
+/*!
+ * Equivalent to mkdir(2), can succeed if the directory already exists.
+ */
+int fs_mkdir(const char *path, mode_t mode, bool ignore_existing);
diff --git a/src/libdnssec/shared/hex.c b/src/libdnssec/shared/hex.c
new file mode 100644
index 0000000..03c1491
--- /dev/null
+++ b/src/libdnssec/shared/hex.c
@@ -0,0 +1,167 @@
+/*  Copyright (C) 2018 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 <http://www.gnu.org/licenses/>.
+*/
+
+#include <assert.h>
+#include <string.h>
+#include <stdbool.h>
+
+#include "libdnssec/binary.h"
+#include "libdnssec/error.h"
+
+#include "contrib/ctype.h"
+
+/* -- binary to hex -------------------------------------------------------- */
+
+static const char BIN_TO_HEX[] = { '0', '1', '2', '3', '4', '5', '6', '7',
+				   '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
+
+int bin_to_hex_static(const dnssec_binary_t *bin, dnssec_binary_t *hex)
+{
+	if (!bin || !hex) {
+		return DNSSEC_EINVAL;
+	}
+
+	if (bin->size * 2 != hex->size) {
+		return DNSSEC_EINVAL;
+	}
+
+	for (size_t i = 0; i < bin->size; i++) {
+		hex->data[2*i]   = BIN_TO_HEX[bin->data[i] >> 4];
+		hex->data[2*i+1] = BIN_TO_HEX[bin->data[i] & 0x0f];
+	}
+
+	return DNSSEC_EOK;
+}
+
+int bin_to_hex(const dnssec_binary_t *bin, char **hex_ptr)
+{
+	if (!bin || !hex_ptr) {
+		return DNSSEC_EINVAL;
+	}
+
+	size_t hex_size = bin->size * 2;
+	char *hex = malloc(hex_size + 1);
+	if (!hex) {
+		return DNSSEC_ENOMEM;
+	}
+
+	dnssec_binary_t hex_bin = { .data = (uint8_t *)hex, .size = hex_size };
+	bin_to_hex_static(bin, &hex_bin);
+	hex[hex_size] = '\0';
+
+	*hex_ptr = hex;
+
+	return DNSSEC_EOK;
+}
+
+/* -- hex to binary -------------------------------------------------------- */
+
+/*!
+ * Convert HEX character to numeric value (assumes valid and lowercase input).
+ */
+static uint8_t hex_to_number(const char hex)
+{
+	if (hex >= '0' && hex <= '9') {
+		return hex - '0';
+	} else if (hex >= 'a' && hex <= 'f') {
+		return hex - 'a' + 10;
+	} else {
+		assert(hex >= 'A' && hex <= 'F');
+		return hex - 'A' + 10;
+	}
+}
+
+/*!
+ * Check if the input string has valid size and contains valid characters.
+ */
+static bool hex_valid_input(const dnssec_binary_t *hex)
+{
+	assert(hex);
+
+	if (hex->size % 2 != 0) {
+		return false;
+	}
+
+	for (int i = 0; i < hex->size; i++) {
+		if (!is_xdigit(hex->data[i])) {
+			return false;
+		}
+	}
+
+	return true;
+}
+
+/*!
+ * Perform hex to bin conversion without checking the validity.
+ */
+static void hex_to_bin_convert(const dnssec_binary_t *hex, dnssec_binary_t *bin)
+{
+	assert(hex);
+	assert(bin);
+
+	for (size_t i = 0; i < bin->size; i++) {
+		uint8_t high = hex_to_number(hex->data[2 * i]);
+		uint8_t low  = hex_to_number(hex->data[2 * i + 1]);
+		bin->data[i] = high << 4 | low;
+	}
+}
+
+int hex_to_bin_static(const dnssec_binary_t *hex, dnssec_binary_t *bin)
+{
+	if (!hex || !bin) {
+		return DNSSEC_EINVAL;
+	}
+
+	if (hex->size / 2 != bin->size) {
+		return DNSSEC_EINVAL;
+	}
+
+	if (!hex_valid_input(hex)) {
+		return DNSSEC_MALFORMED_DATA;
+	}
+
+	hex_to_bin_convert(hex, bin);
+
+	return DNSSEC_EOK;
+}
+
+int hex_to_bin(const char *hex_str, dnssec_binary_t *bin)
+{
+	if (!hex_str || !bin) {
+		return DNSSEC_EINVAL;
+	}
+
+	dnssec_binary_t hex = { .data = (uint8_t *)hex_str, .size = strlen(hex_str) };
+	if (!hex_valid_input(&hex)) {
+		return DNSSEC_MALFORMED_DATA;
+	}
+
+	size_t bin_size = hex.size / 2;
+	if (bin_size == 0) {
+		bin->size = 0;
+		bin->data = NULL;
+		return DNSSEC_EOK;
+	}
+
+	int result = dnssec_binary_alloc(bin, bin_size);
+	if (result != DNSSEC_EOK) {
+		return result;
+	}
+
+	hex_to_bin_static(&hex, bin);
+
+	return DNSSEC_EOK;
+}
diff --git a/src/libdnssec/shared/hex.h b/src/libdnssec/shared/hex.h
new file mode 100644
index 0000000..5a47cf4
--- /dev/null
+++ b/src/libdnssec/shared/hex.h
@@ -0,0 +1,39 @@
+/*  Copyright (C) 2018 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 <http://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#include "libdnssec/binary.h"
+
+/*!
+ * Convert binary data to preallocated hexadecimal string.
+ */
+int bin_to_hex_static(const dnssec_binary_t *bin, dnssec_binary_t *hex);
+
+/**
+ * Convert binary data to hexadecimal string.
+ */
+int bin_to_hex(const dnssec_binary_t *bin, char **hex_ptr);
+
+/*!
+ * Convert hex encoded string to preallocated binary data.
+ */
+int hex_to_bin_static(const dnssec_binary_t *hex, dnssec_binary_t *bin);
+
+/*!
+ * Convert hex encoded string to binary data.
+ */
+int hex_to_bin(const char *hex, dnssec_binary_t *bin);
diff --git a/src/libdnssec/shared/keyid_gnutls.c b/src/libdnssec/shared/keyid_gnutls.c
new file mode 100644
index 0000000..4fde08e
--- /dev/null
+++ b/src/libdnssec/shared/keyid_gnutls.c
@@ -0,0 +1,94 @@
+/*  Copyright (C) 2018 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 <http://www.gnu.org/licenses/>.
+*/
+
+#include <assert.h>
+#include <gnutls/abstract.h>
+#include <gnutls/gnutls.h>
+#include <gnutls/x509.h>
+#include <string.h>
+
+#include "libdnssec/binary.h"
+#include "libdnssec/error.h"
+#include "libdnssec/keyid.h"
+#include "libdnssec/shared/keyid_gnutls.h"
+#include "libdnssec/shared/shared.h"
+#include "libdnssec/shared/hex.h"
+
+/*!
+ * Get binary key ID from a key (public or private).
+ */
+static int keyid_bin(gnutls_x509_privkey_t key, gnutls_pubkey_t pubkey, dnssec_binary_t *id)
+{
+	assert(key || pubkey);
+	assert(id);
+
+	// Flags can be used to enable SHA-2 since GnuTLS 3.4.7.
+
+	int flags = 0;
+	uint8_t *buffer = alloca(DNSSEC_KEYID_BINARY_SIZE);
+	size_t size = DNSSEC_KEYID_SIZE;
+
+	int r = key ? gnutls_x509_privkey_get_key_id(key, flags, buffer, &size)
+	            : gnutls_pubkey_get_key_id(pubkey, flags, buffer, &size);
+
+	if (r != GNUTLS_E_SUCCESS || size != DNSSEC_KEYID_BINARY_SIZE) {
+		return DNSSEC_INVALID_KEY_ID;
+	}
+
+	assert(size == DNSSEC_KEYID_BINARY_SIZE);
+	r = dnssec_binary_resize(id, size);
+	if (r != DNSSEC_EOK) {
+		return r;
+	}
+
+	memcpy(id->data, buffer, size);
+
+	return DNSSEC_EOK;
+}
+
+/*!
+ * Get hexadecimal key ID from a key (public or private).
+ */
+static int keyid_hex(gnutls_x509_privkey_t key, gnutls_pubkey_t pubkey, char **id)
+{
+	_cleanup_binary_ dnssec_binary_t bin = { 0 };
+	int r = keyid_bin(key, pubkey, &bin);
+	if (r != DNSSEC_EOK) {
+		return r;
+	}
+
+	return bin_to_hex(&bin, id);
+}
+
+int keyid_x509(gnutls_x509_privkey_t key, dnssec_binary_t *id)
+{
+	return keyid_bin(key, NULL, id);
+}
+
+int keyid_x509_hex(gnutls_x509_privkey_t key, char **id)
+{
+	return keyid_hex(key, NULL, id);
+}
+
+int keyid_pubkey(gnutls_pubkey_t pubkey, dnssec_binary_t *id)
+{
+	return keyid_bin(NULL, pubkey, id);
+}
+
+int keyid_pubkey_hex(gnutls_pubkey_t pubkey, char **id)
+{
+	return keyid_hex(NULL, pubkey, id);
+}
diff --git a/src/libdnssec/shared/keyid_gnutls.h b/src/libdnssec/shared/keyid_gnutls.h
new file mode 100644
index 0000000..27ee4cd
--- /dev/null
+++ b/src/libdnssec/shared/keyid_gnutls.h
@@ -0,0 +1,30 @@
+/*  Copyright (C) 2018 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 <http://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#include <gnutls/abstract.h>
+#include <gnutls/gnutls.h>
+
+#include "libdnssec/binary.h"
+
+int keyid_x509(gnutls_x509_privkey_t key, dnssec_binary_t *id);
+
+int keyid_x509_hex(gnutls_x509_privkey_t key, char **id);
+
+int keyid_pubkey(gnutls_pubkey_t pubkey, dnssec_binary_t *id);
+
+int keyid_pubkey_hex(gnutls_pubkey_t pubkey, char **id);
diff --git a/src/libdnssec/shared/pem.c b/src/libdnssec/shared/pem.c
new file mode 100644
index 0000000..0e5ba00
--- /dev/null
+++ b/src/libdnssec/shared/pem.c
@@ -0,0 +1,198 @@
+/*  Copyright (C) 2018 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 <http://www.gnu.org/licenses/>.
+*/
+
+#include <assert.h>
+#include <gnutls/abstract.h>
+#include <gnutls/gnutls.h>
+#include <gnutls/x509.h>
+
+#include "libdnssec/binary.h"
+#include "libdnssec/error.h"
+#include "libdnssec/key.h"
+#include "libdnssec/keyid.h"
+#include "libdnssec/shared/keyid_gnutls.h"
+#include "libdnssec/shared/pem.h"
+#include "libdnssec/shared/shared.h"
+
+/* -- internal API --------------------------------------------------------- */
+
+/*!
+ * Create GnuTLS X.509 private key from unencrypted PEM data.
+ */
+int pem_x509(const dnssec_binary_t *pem, gnutls_x509_privkey_t *key)
+{
+	assert(pem);
+	assert(key);
+
+	gnutls_datum_t data = binary_to_datum(pem);
+
+	gnutls_x509_privkey_t _key = NULL;
+	int r = gnutls_x509_privkey_init(&_key);
+	if (r != GNUTLS_E_SUCCESS) {
+		return DNSSEC_ENOMEM;
+	}
+
+	int format = GNUTLS_X509_FMT_PEM;
+	char *password = NULL;
+	int flags = GNUTLS_PKCS_PLAIN;
+	r = gnutls_x509_privkey_import_pkcs8(_key, &data, format, password, flags);
+	if (r != GNUTLS_E_SUCCESS) {
+		gnutls_x509_privkey_deinit(_key);
+		return DNSSEC_PKCS8_IMPORT_ERROR;
+	}
+
+	*key = _key;
+
+	return DNSSEC_EOK;
+}
+
+/*!
+ * Create GnuTLS private key from unencrypted PEM data.
+ */
+int pem_privkey(const dnssec_binary_t *pem, gnutls_privkey_t *key)
+{
+	assert(pem);
+	assert(key);
+
+	gnutls_x509_privkey_t key_x509 = NULL;
+	int r = pem_x509(pem, &key_x509);
+	if (r != DNSSEC_EOK) {
+		return r;
+	}
+
+	gnutls_privkey_t key_abs = NULL;
+	r = gnutls_privkey_init(&key_abs);
+	if (r != GNUTLS_E_SUCCESS) {
+		gnutls_x509_privkey_deinit(key_x509);
+		return DNSSEC_ENOMEM;
+	}
+
+	int flags = GNUTLS_PRIVKEY_IMPORT_AUTO_RELEASE;
+	r = gnutls_privkey_import_x509(key_abs, key_x509, flags);
+	if (r != GNUTLS_E_SUCCESS) {
+		gnutls_x509_privkey_deinit(key_x509);
+		gnutls_privkey_deinit(key_abs);
+		return DNSSEC_ENOMEM;
+	}
+
+	*key = key_abs;
+
+	return DNSSEC_EOK;
+}
+
+/*!
+ * Generate new key and export it in the PEM format.
+ */
+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 = 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;
+}
+
+static int try_export_pem(gnutls_x509_privkey_t key, dnssec_binary_t *pem)
+{
+	assert(key);
+
+	gnutls_x509_crt_fmt_t format = GNUTLS_X509_FMT_PEM;
+	char *password = NULL;
+	int flags = GNUTLS_PKCS_PLAIN;
+
+	return gnutls_x509_privkey_export_pkcs8(key, format, password, flags,
+						pem->data, &pem->size);
+}
+
+/*!
+ * Export GnuTLS X.509 private key to PEM binary.
+ */
+int pem_from_x509(gnutls_x509_privkey_t key, dnssec_binary_t *pem)
+{
+	assert(key);
+	assert(pem);
+
+	dnssec_binary_t _pem = { 0 };
+	int r = try_export_pem(key, &_pem);
+	if (r != GNUTLS_E_SHORT_MEMORY_BUFFER || _pem.size == 0) {
+		return DNSSEC_KEY_EXPORT_ERROR;
+	}
+
+	r = dnssec_binary_alloc(&_pem, _pem.size);
+	if (r != DNSSEC_EOK) {
+		return r;
+	}
+
+	r = try_export_pem(key, &_pem);
+	if (r != GNUTLS_E_SUCCESS) {
+		dnssec_binary_free(&_pem);
+		return DNSSEC_KEY_EXPORT_ERROR;
+	}
+
+	*pem = _pem;
+
+	return DNSSEC_EOK;
+}
+
+/*!
+ * Get key ID of a private key in PEM format.
+ */
+int pem_keyid(const dnssec_binary_t *pem, char **id)
+{
+	assert(pem && pem->size > 0 && pem->data);
+	assert(id);
+
+	_cleanup_x509_privkey_ gnutls_x509_privkey_t key = NULL;
+	int r = pem_x509(pem, &key);
+	if (r != DNSSEC_EOK) {
+		return r;
+	}
+
+	return keyid_x509_hex(key, id);
+}
diff --git a/src/libdnssec/shared/pem.h b/src/libdnssec/shared/pem.h
new file mode 100644
index 0000000..c96065b
--- /dev/null
+++ b/src/libdnssec/shared/pem.h
@@ -0,0 +1,74 @@
+/*  Copyright (C) 2018 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 <http://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#include <gnutls/gnutls.h>
+
+#include "libdnssec/binary.h"
+
+/*!
+ * Create GnuTLS X.509 private key from unencrypted PEM data.
+ *
+ * \param[in]  pem  PEM binary data.
+ * \param[out] key  Resulting private key.
+ *
+ * \return Error code, DNSSEC_EOK if successful.
+ */
+int pem_x509(const dnssec_binary_t *pem, gnutls_x509_privkey_t *key);
+
+/*!
+ * Create GnuTLS private key from unencrypted PEM data.
+ *
+ * \param[in]  pem  PEM binary data.
+ * \param[out] key  Resulting private key.
+ *
+ * \return Error code, DNSSEC_EOK if successful.
+ */
+int pem_privkey(const dnssec_binary_t *pem, gnutls_privkey_t *key);
+
+/*!
+ * Generate a private key and export it in the PEM format.
+ *
+ * \param[in]  algorithm  Algorithm to be used.
+ * \param[in]  bits       Size of the key to be generated.
+ * \param[out] pem        Generated key in unencrypted PEM format.
+ * \param[out] id         Key ID of the generated key.
+ *
+ * \return Error code, DNSSEC_EOK if successful.
+ */
+int pem_generate(gnutls_pk_algorithm_t algorithm, unsigned bits,
+		 dnssec_binary_t *pem, char **id);
+
+/*!
+ * Export GnuTLS X.509 private key to PEM binary.
+ *
+ * \param[in]  key  Key to be exported.
+ * \param[out] pem  Generated key in unencrypted PEM format.
+ *
+ * \return Error code, DNSSEC_EOK if successful.
+ */
+int pem_from_x509(gnutls_x509_privkey_t key, dnssec_binary_t *pem);
+
+/*!
+ * Get key ID of a private key in PEM format.
+ *
+ * \param[in]  pem  Key in unencrypted PEM format.
+ * \param[out] id   ID of the key.
+ *
+ * \return Error code, DNSSEC_EOK if successful.
+ */
+int pem_keyid(const dnssec_binary_t *pem, char **id);
diff --git a/src/libdnssec/shared/shared.h b/src/libdnssec/shared/shared.h
new file mode 100644
index 0000000..1f55033
--- /dev/null
+++ b/src/libdnssec/shared/shared.h
@@ -0,0 +1,129 @@
+/*  Copyright (C) 2018 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 <http://www.gnu.org/licenses/>.
+*/
+
+#pragma once
+
+#include <assert.h>
+#include <dirent.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <gnutls/abstract.h>
+#include <gnutls/crypto.h>
+#include <gnutls/gnutls.h>
+#include <gnutls/x509.h>
+
+#include "libdnssec/binary.h"
+
+#define _public_ __attribute__((visibility("default")))
+#define _hidden_ __attribute__((visibility("hidden")))
+
+#define _unused_ __attribute__((unused))
+
+/**
+ * Macro to clear a structure of known size.
+ *
+ * \param pointer Pointer to the structure.
+ */
+#define clear_struct(pointer) memset((pointer), '\0', sizeof(*(pointer)))
+
+#define streq(one, two) (strcmp((one), (two)) == 0)
+
+/* -- cleanup macros ------------------------------------------------------- */
+
+#define _cleanup_(var) __attribute__((cleanup(var)))
+
+static inline void free_ptr(void *ptr)
+{
+	free(*(void **)ptr);
+}
+
+static inline void close_ptr(int *ptr)
+{
+	if (*ptr != -1) {
+		close(*ptr);
+	}
+}
+
+static inline void fclose_ptr(FILE **ptr)
+{
+	if (*ptr) {
+		fclose(*ptr);
+	}
+}
+
+static inline void closedir_ptr(DIR **ptr)
+{
+	if (*ptr) {
+		closedir(*ptr);
+	}
+}
+
+static inline void free_gnutls_datum_ptr(gnutls_datum_t *ptr)
+{
+	gnutls_free(ptr->data);
+}
+
+static inline void free_x509_privkey_ptr(gnutls_x509_privkey_t *ptr)
+{
+	if (*ptr) {
+		gnutls_x509_privkey_deinit(*ptr);
+	}
+}
+
+static inline void free_pubkey_ptr(gnutls_pubkey_t *ptr)
+{
+	if (*ptr) {
+		gnutls_pubkey_deinit(*ptr);
+	}
+}
+
+static inline void free_gnutls_hash_ptr(gnutls_hash_hd_t *ptr)
+{
+	if (*ptr) {
+		gnutls_hash_deinit(*ptr, NULL);
+	}
+}
+
+#define _cleanup_free_ _cleanup_(free_ptr)
+#define _cleanup_close_ _cleanup_(close_ptr)
+#define _cleanup_fclose_ _cleanup_(fclose_ptr)
+#define _cleanup_closedir_ _cleanup_(closedir_ptr)
+#define _cleanup_binary_ _cleanup_(dnssec_binary_free)
+#define _cleanup_datum_ _cleanup_(free_gnutls_datum_ptr)
+#define _cleanup_x509_privkey_ _cleanup_(free_x509_privkey_ptr)
+#define _cleanup_pubkey_ _cleanup_(free_pubkey_ptr)
+#define _cleanup_hash_ _cleanup_(free_gnutls_hash_ptr)
+
+/* -- assertions ----------------------------------------------------------- */
+
+#define assert_unreachable() assert(0)
+
+/* -- crypto helpers ------------------------------------------------------- */
+
+static inline gnutls_datum_t binary_to_datum(const dnssec_binary_t *from)
+{
+	gnutls_datum_t to = { .size = from->size, .data = from->data };
+	return to;
+}
+
+static inline dnssec_binary_t binary_from_datum(const gnutls_datum_t *from)
+{
+	dnssec_binary_t to = { .size = from->size, .data = from->data };
+	return to;
+}