Merge branch 'ssh-eddsa'

This adds support for Ed25519/Ed448 SSH keys and their signatures via
agent plugin.

Author: tobiasbrunner

src/charon-cmd/charon-cmd.c

@@ -358,9 +358,6 @@ int main(int argc, char *argv[])
 	creds = cmd_creds_create();
 	atexit(cleanup_creds);
 
-	/* handle all arguments */
-	handle_arguments(argc, argv, FALSE);
-
 	if (uname(&utsname) != 0)
 	{
 		memset(&utsname, 0, sizeof(utsname));
@@ -369,6 +366,9 @@ int main(int argc, char *argv[])
 		 VERSION, utsname.sysname, utsname.release, utsname.machine);
 	lib->plugins->status(lib->plugins, LEVEL_CTRL);
 
+	/* handle all arguments */
+	handle_arguments(argc, argv, FALSE);
+
 	/* add handler for SEGV and ILL,
 	 * INT, TERM and HUP are handled by sigwaitinfo() in run() */
 	action.sa_handler = segv_handler;

src/libstrongswan/credentials/builder.c

@@ -73,6 +73,7 @@ ENUM(builder_part_names, BUILD_FROM_FILE, BUILD_END,
 	"BUILD_SAFE_PRIMES",
 	"BUILD_SHARES",
 	"BUILD_THRESHOLD",
+	"BUILD_EDDSA_PUB",
 	"BUILD_EDDSA_PRIV_ASN1_DER",
 	"BUILD_END",
 );

src/libstrongswan/credentials/builder.h

@@ -156,6 +156,8 @@ enum builder_part_t {
 	BUILD_SHARES,
 	/** minimum number of participating private key shares */
 	BUILD_THRESHOLD,
+	/** EdDSA public key blob */
+	BUILD_EDDSA_PUB,
 	/** DER encoded ASN.1 EdDSA private key */
 	BUILD_EDDSA_PRIV_ASN1_DER,
 	/** end of variable argument builder list */

src/libstrongswan/plugins/agent/agent_private_key.c

@@ -248,6 +248,12 @@ static bool scheme_supported(private_agent_private_key_t *this,
 					break;
 			}
 			return FALSE;
+		case KEY_ED25519:
+			*prefix = "ssh-ed25519";
+			return scheme == SIGN_ED25519;
+		case KEY_ED448:
+			*prefix = "ssh-ed448";
+			return scheme == SIGN_ED448;
 		case KEY_ECDSA:
 			return scheme == SIGN_ECDSA_256 ||
 				   scheme == SIGN_ECDSA_384 ||
@@ -261,6 +267,7 @@ METHOD(private_key_t, sign, bool,
 	private_agent_private_key_t *this, signature_scheme_t scheme, void *params,
 	chunk_t data, chunk_t *signature)
 {
+	key_type_t type;
 	uint32_t len, flags = 0;
 	char buf[2048], *prefix = NULL;
 	chunk_t blob;
@@ -321,9 +328,9 @@ METHOD(private_key_t, sign, bool,
 		DBG1(DBG_LIB, "ssh-agent didn't return requested %s signature", prefix);
 		return FALSE;
 	}
-
-	if (this->pubkey->get_type(this->pubkey) == KEY_RSA)
-	{	/* for RSA, the signature has no special encoding */
+	type = this->pubkey->get_type(this->pubkey);
+	if (type == KEY_RSA || type == KEY_ED25519 || type == KEY_ED448)
+	{	/* for RSA/EdDSA, the signature has no special encoding */
 		blob = read_string(&blob);
 		if (blob.len)
 		{
@@ -429,12 +436,16 @@ static enumerator_t *create_rsa_enumerator(private_agent_private_key_t *this)
 METHOD(private_key_t, supported_signature_schemes, enumerator_t*,
 	private_agent_private_key_t *this)
 {
-	switch (get_type(this))
+	key_type_t type = get_type(this);
+
+	switch (type)
 	{
 		case KEY_RSA:
 			return create_rsa_enumerator(this);
+		case KEY_ED25519:
+		case KEY_ED448:
 		case KEY_ECDSA:
-			return signature_schemes_for_key(KEY_ECDSA, get_keysize(this));
+			return signature_schemes_for_key(type, get_keysize(this));
 		default:
 			break;
 	}

src/libstrongswan/plugins/curve25519/curve25519_public_key.c

@@ -1,4 +1,5 @@
 /*
+ * Copyright (C) 2018 Tobias Brunner
  * Copyright (C) 2016 Andreas Steffen
  * HSR Hochschule fuer Technik Rapperswil
  *
@@ -199,23 +200,69 @@ static const asn1Object_t pubkeyObjects[] = {
 #define ED25519_SUBJECT_PUBLIC_KEY_ALGORITHM	1
 #define ED25519_SUBJECT_PUBLIC_KEY				2
 
+/**
+ * Parse the ASN.1-encoded subjectPublicKeyInfo
+ */
+static bool parse_public_key_info(private_curve25519_public_key_t *this,
+								  chunk_t blob)
+{
+	asn1_parser_t *parser;
+	chunk_t object;
+	bool success = FALSE;
+	int objectID, oid;
+
+	parser = asn1_parser_create(pubkeyObjects, blob);
+
+	while (parser->iterate(parser, &objectID, &object))
+	{
+		switch (objectID)
+		{
+			case ED25519_SUBJECT_PUBLIC_KEY_ALGORITHM:
+			{
+				oid = asn1_parse_algorithmIdentifier(object,
+										parser->get_level(parser) + 1, NULL);
+				if (oid != OID_ED25519)
+				{
+					goto end;
+				}
+				break;
+			}
+			case ED25519_SUBJECT_PUBLIC_KEY:
+			{
+				/* encoded as an ASN1 BIT STRING */
+				if (object.len != 1 + ED25519_KEY_LEN)
+				{
+					goto end;
+				}
+				this->pubkey = chunk_clone(chunk_skip(object, 1));
+				break;
+			}
+		}
+	}
+	success = parser->success(parser);
+
+end:
+	parser->destroy(parser);
+	return success;
+}
+
 /**
  * See header.
  */
 curve25519_public_key_t *curve25519_public_key_load(key_type_t type,
 													va_list args)
 {
 	private_curve25519_public_key_t *this;
-	chunk_t blob = chunk_empty, object;
-	asn1_parser_t *parser;
-	bool success = FALSE;
-	int objectID, oid;
+	chunk_t asn1 = chunk_empty, blob = chunk_empty;
 
 	while (TRUE)
 	{
 		switch (va_arg(args, builder_part_t))
 		{
 			case BUILD_BLOB_ASN1_DER:
+				asn1 = va_arg(args, chunk_t);
+				continue;
+			case BUILD_EDDSA_PUB:
 				blob = va_arg(args, chunk_t);
 				continue;
 			case BUILD_END:
@@ -244,39 +291,11 @@ curve25519_public_key_t *curve25519_public_key_load(key_type_t type,
 		.ref = 1,
 	);
 
-	parser = asn1_parser_create(pubkeyObjects, blob);
-
-	while (parser->iterate(parser, &objectID, &object))
+	if (blob.len == ED25519_KEY_LEN)
 	{
-		switch (objectID)
-		{
-			case ED25519_SUBJECT_PUBLIC_KEY_ALGORITHM:
-			{
-				oid = asn1_parse_algorithmIdentifier(object,
-										parser->get_level(parser) + 1, NULL);
-				if (oid != OID_ED25519)
-				{
-					goto end;
-				}
-				break;
-			}
-			case ED25519_SUBJECT_PUBLIC_KEY:
-			{
-				/* encoded as an ASN1 BIT STRING */
-				if (object.len != 1 + ED25519_KEY_LEN)
-				{
-					goto end;
-				}
-				this->pubkey = chunk_clone(chunk_skip(object, 1));
-				break;
-			}
-		}
+		this->pubkey = chunk_clone(blob);
 	}
-	success = parser->success(parser);
-
-end:
-	parser->destroy(parser);
-	if (!success)
+	else if (!asn1.len || !parse_public_key_info(this, asn1))
 	{
 		destroy(this);
 		return NULL;

src/libstrongswan/plugins/sshkey/sshkey_builder.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2013-2014 Tobias Brunner
+ * Copyright (C) 2013-2018 Tobias Brunner
  * HSR Hochschule fuer Technik Rapperswil
  *
  * This program is free software; you can redistribute it and/or modify it
@@ -89,6 +89,34 @@ static sshkey_public_key_t *parse_public_key(chunk_t blob)
 		return lib->creds->create(lib->creds, CRED_PUBLIC_KEY, KEY_RSA,
 						BUILD_RSA_MODULUS, n, BUILD_RSA_PUB_EXP, e, BUILD_END);
 	}
+	else if (chunk_equals(format, chunk_from_str("ssh-ed25519")))
+	{
+		chunk_t blob;
+
+		if (!reader->read_data32(reader, &blob))
+		{
+			DBG1(DBG_LIB, "invalid Ed25519 key in SSH key");
+			reader->destroy(reader);
+			return NULL;
+		}
+		reader->destroy(reader);
+		return lib->creds->create(lib->creds, CRED_PUBLIC_KEY, KEY_ED25519,
+								  BUILD_EDDSA_PUB, blob, BUILD_END);
+	}
+	else if (chunk_equals(format, chunk_from_str("ssh-ed448")))
+	{
+		chunk_t blob;
+
+		if (!reader->read_data32(reader, &blob))
+		{
+			DBG1(DBG_LIB, "invalid Ed448 key in SSH key");
+			reader->destroy(reader);
+			return NULL;
+		}
+		reader->destroy(reader);
+		return lib->creds->create(lib->creds, CRED_PUBLIC_KEY, KEY_ED448,
+								  BUILD_EDDSA_PUB, blob, BUILD_END);
+	}
 	else if (format.len > strlen(ECDSA_PREFIX) &&
 			 strpfx(format.ptr, ECDSA_PREFIX))
 	{
@@ -140,8 +168,9 @@ static sshkey_public_key_t *load_from_stream(FILE *file)
 	char line[1024], *token;
 
 	while (!public && fgets(line, sizeof(line), file))
-	{	/* the format is: ssh-rsa|ecdsa-... <key(base64)> <identifier> */
-		if (!strpfx(line, "ssh-rsa") && !strpfx(line, ECDSA_PREFIX))
+	{	/* the format is: ssh-<key-type> <key(base64)> <identifier> */
+		if (!strpfx(line, "ssh-rsa") && !strpfx(line, ECDSA_PREFIX) &&
+			!strpfx(line, "ssh-ed25519") && !strpfx(line, "ssh-ed448"))
 		{
 			continue;
 		}

src/libstrongswan/plugins/sshkey/sshkey_encoder.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2013 Tobias Brunner
+ * Copyright (C) 2013-2018 Tobias Brunner
  * HSR Hochschule fuer Technik Rapperswil
  *
  * This program is free software; you can redistribute it and/or modify it
@@ -72,6 +72,42 @@ static bool build_public_key(chunk_t *encoding, va_list args)
 		writer->destroy(writer);
 		return TRUE;
 	}
+	else if (cred_encoding_args(args, CRED_PART_EDDSA_PUB_ASN1_DER, &n,
+								CRED_PART_END))
+	{
+		chunk_t alg;
+		char *prefix;
+		int oid;
+
+		/* parse subjectPublicKeyInfo */
+		if (asn1_unwrap(&n, &n) != ASN1_SEQUENCE)
+		{
+			return FALSE;
+		}
+		oid = asn1_parse_algorithmIdentifier(n, 1, NULL);
+		switch (oid)
+		{
+			case OID_ED25519:
+				prefix = "ssh-ed25519";
+				break;
+			case OID_ED448:
+				prefix = "ssh-ed448";
+				break;
+			default:
+				return FALSE;
+		}
+		if (asn1_unwrap(&n, &alg) != ASN1_SEQUENCE ||
+			asn1_unwrap(&n, &n) != ASN1_BIT_STRING || !n.len)
+		{
+			return FALSE;
+		}
+		writer = bio_writer_create(0);
+		writer->write_data32(writer, chunk_from_str(prefix));
+		writer->write_data32(writer, chunk_skip(n, 1));
+		*encoding = chunk_to_base64(writer->get_buf(writer), NULL);
+		writer->destroy(writer);
+		return TRUE;
+	}
 	else if (cred_encoding_args(args, CRED_PART_ECDSA_PUB_ASN1_DER, &n,
 								CRED_PART_END))
 	{