scripts: Add script to extract the ASN.1 subject DN from a certificate

This can be useful if the subject DN has to be configured with the
asn1dn: prefix in ipsec.conf (e.g. because the actual encoding can't be
created by strongSwan's string parser/encoder).

2 files changed, 157 insertions, 1 deletions

diff --git a/scripts/Makefile.am b/scripts/Makefile.am
index a793800b7..25456700b 100644
--- a/scripts/Makefile.am
+++ b/scripts/Makefile.am
@@ -5,7 +5,7 @@ AM_CPPFLAGS = \
 
 noinst_PROGRAMS = bin2array bin2sql id2sql key2keyid keyid2sql oid2der \
 	thread_analysis dh_speed pubkey_speed crypt_burn hash_burn fetch \
-	dnssec malloc_speed aes-test settings-test timeattack
+	dnssec malloc_speed aes-test settings-test timeattack extract-dn
 
 if USE_TLS
   noinst_PROGRAMS += tls_test
@@ -30,6 +30,7 @@ fetch_SOURCES = fetch.c
 dnssec_SOURCES = dnssec.c
 timeattack_SOURCES = timeattack.c
 id2sql_LDADD = $(top_builddir)/src/libstrongswan/libstrongswan.la
+extract_dn_LDADD = $(top_builddir)/src/libstrongswan/libstrongswan.la
 key2keyid_LDADD = $(top_builddir)/src/libstrongswan/libstrongswan.la
 keyid2sql_LDADD = $(top_builddir)/src/libstrongswan/libstrongswan.la
 oid2der_LDADD = $(top_builddir)/src/libstrongswan/libstrongswan.la
diff --git a/scripts/extract-dn.c b/scripts/extract-dn.c
new file mode 100644
index 000000000..01261422e
--- /dev/null
+++ b/scripts/extract-dn.c
@@ -0,0 +1,155 @@
+/*
+ * Copyright (C) 2015 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * 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.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * 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.
+ */
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+#include <getopt.h>
+
+#include <library.h>
+
+static void usage(FILE *out, char *name)
+{
+	fprintf(out, "Extract the ASN.1 subject DN from a certificate\n\n");
+	fprintf(out, "%s [OPTIONS]\n\n", name);
+	fprintf(out, "Options:\n");
+	fprintf(out, "  -h, --help          print this help.\n");
+	fprintf(out, "  -i, --in=FILE       certificate file (default STDIN).\n");
+	fprintf(out, "  -f, --format=FORMAT output format (config, hex, base64, binary).\n");
+	fprintf(out, "\n");
+}
+
+/**
+ * Extract the binary ASN.1 subject DN from a certificate
+ */
+int main(int argc, char *argv[])
+{
+	identification_t *id;
+	certificate_t *cert;
+	chunk_t chunk;
+	enum {
+		FORMAT_CONFIG,
+		FORMAT_HEX,
+		FORMAT_BASE64,
+		FORMAT_BINARY,
+	} format = FORMAT_CONFIG;
+	int fd = 0;
+	char *fmt;
+
+	library_init(NULL, "extract-dn");
+	atexit(library_deinit);
+
+	while (true)
+	{
+		struct option long_opts[] = {
+			{"help",		no_argument,		NULL,	'h' },
+			{"in",			required_argument,	NULL,	'i' },
+			{"format",		required_argument,	NULL,	'f' },
+			{0,0,0,0 },
+		};
+		switch (getopt_long(argc, argv, "hi:f:", long_opts, NULL))
+		{
+			case EOF:
+				break;
+			case 'h':
+				usage(stdout, argv[0]);
+				return 0;
+			case 'i':
+				fd = open(optarg, O_RDONLY);
+				if (fd == -1)
+				{
+					fprintf(stderr, "failed to open '%s': %s\n", optarg,
+							strerror(errno));
+					usage(stderr, argv[0]);
+					return 1;
+				}
+				continue;
+			case 'f':
+				if (streq(optarg, "hex"))
+				{
+					format = FORMAT_HEX;
+				}
+				else if (streq(optarg, "base64"))
+				{
+					format = FORMAT_BASE64;
+				}
+				else if (streq(optarg, "bin"))
+				{
+					format = FORMAT_BINARY;
+				}
+				continue;
+			default:
+				usage(stderr, argv[0]);
+				return 1;
+		}
+		break;
+	}
+	/* TODO: maybe make plugins configurable */
+	lib->plugins->load(lib->plugins, PLUGINS);
+
+	if (!chunk_from_fd(fd, &chunk))
+	{
+		fprintf(stderr, "reading input failed: %s\n", strerror(errno));
+		return 1;
+	}
+	cert = lib->creds->create(lib->creds, CRED_CERTIFICATE, CERT_X509,
+							  BUILD_BLOB, chunk, BUILD_END);
+	chunk_free(&chunk);
+	if (fd != 0)
+	{
+		close(fd);
+	}
+
+	if (!cert)
+	{
+		fprintf(stderr, "failed to read certificate\n");
+		return 1;
+	}
+	id = cert->get_subject(cert);
+	if (!id)
+	{
+		fprintf(stderr, "failed to get certificate's subject DN\n");
+		cert->destroy(cert);
+		return 1;
+	}
+	fmt = "%.*s\n";
+	switch (format)
+	{
+		case FORMAT_CONFIG:
+			fmt = "\"asn1dn:#%.*s\"\n";
+			/* fall-through */
+		case FORMAT_HEX:
+			chunk = chunk_to_hex(id->get_encoding(id), NULL, FALSE);
+			printf(fmt, (int)chunk.len, chunk.ptr);
+			chunk_free(&chunk);
+			break;
+		case FORMAT_BASE64:
+			chunk = chunk_to_base64(id->get_encoding(id), NULL);
+			printf(fmt, (int)chunk.len, chunk.ptr);
+			chunk_free(&chunk);
+			break;
+		case FORMAT_BINARY:
+			chunk = id->get_encoding(id);
+			if (fwrite(chunk.ptr, chunk.len, 1, stdout) != 1)
+			{
+				fprintf(stderr, "writing subject DN failed\n");
+			}
+			break;
+	}
+	cert->destroy(cert);
+	return 0;
+}