Add Ed25519 support

.travis.yml

@@ -57,6 +57,7 @@ script:
   - ~/inst/bin/dropbearkey -t ecdsa -f testec256 -s 256
   - ~/inst/bin/dropbearkey -t ecdsa -f testec384 -s 384
   - ~/inst/bin/dropbearkey -t ecdsa -f testec521 -s 521
+  - ~/inst/bin/dropbearkey -t ed25519 -f tested25519
   - test -z $DO_FUZZ || ./fuzzers_test.sh
 
 branches:

FUZZER-NOTES.md

@@ -72,3 +72,6 @@ Current fuzzers are
 
 - [fuzzer-kexecdh](fuzzer-kexecdh.c) - test Elliptic Curve Diffie-Hellman key exchange like fuzzer-kexdh.
   This is testing libtommath ECC routines.
+
+- [fuzzer-kexcurve25519](fuzzer-kexcurve25519.c) - test Curve25519 Elliptic Curve Diffie-Hellman key exchange
+  like fuzzer-kexecdh. This is testing `dropbear_curve25519_scalarmult()` and other libtommath routines.

LICENSE

@@ -90,52 +90,25 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 =====
 
-curve25519-donna:
-
-/* Copyright 2008, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- * curve25519-donna: Curve25519 elliptic curve, public key function
- *
- * http://code.google.com/p/curve25519-donna/
- *
- * Adam Langley <agl@imperialviolet.org>
- *
- * Derived from public domain C code by Daniel J. Bernstein <djb@cr.yp.to>
- *
- * More information about curve25519 can be found here
- *   http://cr.yp.to/ecdh.html
- *
- * djb's sample implementation of curve25519 is written in a special assembly
- * language called qhasm and uses the floating point registers.
- *
- * This is, almost, a clean room reimplementation from the curve25519 paper. It
- * uses many of the tricks described therein. Only the crecip function is taken
- * from the sample implementation.
- */
+crypto25519.c:
+crypto26619.h:
+
+Modified TweetNaCl version 20140427, a self-contained public-domain C library.
+https://tweetnacl.cr.yp.to/
+
+Contributors (alphabetical order)
+Daniel J. Bernstein, University of Illinois at Chicago and Technische
+Universiteit Eindhoven
+Bernard van Gastel, Radboud Universiteit Nijmegen
+Wesley Janssen, Radboud Universiteit Nijmegen
+Tanja Lange, Technische Universiteit Eindhoven
+Peter Schwabe, Radboud Universiteit Nijmegen
+Sjaak Smetsers, Radboud Universiteit Nijmegen
+
+Acknowledgments
+This work was supported by the U.S. National Science Foundation under grant
+1018836. "Any opinions, findings, and conclusions or recommendations expressed
+in this material are those of the author(s) and do not necessarily reflect the
+views of the National Science Foundation."
+This work was supported by the Netherlands Organisation for Scientific
+Research (NWO) under grant 639.073.005 and Veni 2013 project 13114.

Makefile.in

@@ -36,8 +36,9 @@ COMMONOBJS=dbutil.o buffer.o dbhelpers.o \
 		queue.o \
 		atomicio.o compat.o fake-rfc2553.o \
 		ltc_prng.o ecc.o ecdsa.o crypto_desc.o \
+		curve25519.o ed25519.o \
 		dbmalloc.o \
-		gensignkey.o gendss.o genrsa.o
+		gensignkey.o gendss.o genrsa.o gened25519.o
 
 SVROBJS=svr-kex.o svr-auth.o sshpty.o \
 		svr-authpasswd.o svr-authpubkey.o svr-authpubkeyoptions.o svr-session.o svr-service.o \
@@ -52,7 +53,7 @@ CLIOBJS=cli-main.o cli-auth.o cli-authpasswd.o cli-kex.o \
 CLISVROBJS=common-session.o packet.o common-algo.o common-kex.o \
 			common-channel.o common-chansession.o termcodes.o loginrec.o \
 			tcp-accept.o listener.o process-packet.o dh_groups.o \
-			common-runopts.o circbuffer.o curve25519-donna.o list.o netio.o
+			common-runopts.o circbuffer.o list.o netio.o
 
 KEYOBJS=dropbearkey.o
 
@@ -264,7 +265,7 @@ tidy:
 ## Fuzzing targets
 
 # list of fuzz targets
-FUZZ_TARGETS=fuzzer-preauth fuzzer-pubkey fuzzer-verify fuzzer-preauth_nomaths fuzzer-kexdh fuzzer-kexecdh
+FUZZ_TARGETS=fuzzer-preauth fuzzer-pubkey fuzzer-verify fuzzer-preauth_nomaths fuzzer-kexdh fuzzer-kexecdh fuzzer-kexcurve25519
 
 FUZZER_OPTIONS = $(addsuffix .options, $(FUZZ_TARGETS))
 
@@ -303,6 +304,9 @@ fuzzer-kexdh: fuzzer-kexdh.o fuzz-harness.o
 fuzzer-kexecdh: fuzzer-kexecdh.o fuzz-harness.o
 	$(CXX) $(CXXFLAGS) $@.o $(LDFLAGS) $(svrfuzzobjs) -o $@$(EXEEXT) $(LIBTOM_LIBS) $(LIBS) $(FUZZLIB) @CRYPTLIB@
 
+fuzzer-kexcurve25519: fuzzer-kexcurve25519.o fuzz-harness.o
+	$(CXX) $(CXXFLAGS) $@.o $(LDFLAGS) $(svrfuzzobjs) -o $@$(EXEEXT) $(LIBTOM_LIBS) $(LIBS) $(FUZZLIB) @CRYPTLIB@
+
 fuzzer-%.options: Makefile
 	echo "[libfuzzer]"               > $@
 	echo "max_len = 50000"          >> $@
@@ -313,7 +317,9 @@ fuzz-hostkeys:
 	dropbearkey -t rsa -f keyr
 	dropbearkey -t dss -f keyd
 	dropbearkey -t ecdsa -size 256 -f keye
+	dropbearkey -t ed25519 -f keyed25519
 	echo > hostkeys.c
 	/usr/bin/xxd -i -a keyr >> hostkeys.c
 	/usr/bin/xxd -i -a keye >> hostkeys.c
 	/usr/bin/xxd -i -a keyd >> hostkeys.c
+	/usr/bin/xxd -i -a keyed25519 >> hostkeys.c

README

@@ -55,6 +55,7 @@ To run the server, you need to generate server keys, this is one-off:
 ./dropbearkey -t rsa -f dropbear_rsa_host_key
 ./dropbearkey -t dss -f dropbear_dss_host_key
 ./dropbearkey -t ecdsa -f dropbear_ecdsa_host_key
+./dropbearkey -t ed25519 -f dropbear_ed25519_host_key
 
 or alternatively convert OpenSSH keys to Dropbear:
 ./dropbearconvert openssh dropbear /etc/ssh/ssh_host_dsa_key dropbear_dss_host_key

cli-kex.c

@@ -81,7 +81,7 @@ void send_msg_kexdh_init() {
 				}
 				cli_ses.curve25519_param = gen_kexcurve25519_param();
 			}
-			buf_putstring(ses.writepayload, (const char*)cli_ses.curve25519_param->pub, CURVE25519_LEN);
+			buf_putstring(ses.writepayload, cli_ses.curve25519_param->pub, CURVE25519_LEN);
 			break;
 #endif
 	}

common-algo.c

@@ -222,6 +222,9 @@ algo_type ssh_nocompress[] = {
 };
 
 algo_type sshhostkey[] = {
+#if DROPBEAR_ED25519
+	{"ssh-ed25519", DROPBEAR_SIGNKEY_ED25519, NULL, 1, NULL},
+#endif
 #if DROPBEAR_ECDSA
 #if DROPBEAR_ECC_256
 	{"ecdsa-sha2-nistp256", DROPBEAR_SIGNKEY_ECDSA_NISTP256, NULL, 1, NULL},

common-kex.c

@@ -36,6 +36,7 @@
 #include "dbrandom.h"
 #include "runopts.h"
 #include "ecc.h"
+#include "curve25519.h"
 #include "crypto_desc.h"
 
 static void kexinitialise(void);
@@ -703,23 +704,18 @@ void kexecdh_comb_key(struct kex_ecdh_param *param, buffer *pub_them,
 #endif /* DROPBEAR_ECDH */
 
 #if DROPBEAR_CURVE25519
-struct kex_curve25519_param *gen_kexcurve25519_param () {
+struct kex_curve25519_param *gen_kexcurve25519_param() {
 	/* Per http://cr.yp.to/ecdh.html */
 	struct kex_curve25519_param *param = m_malloc(sizeof(*param));
 	const unsigned char basepoint[32] = {9};
 
 	genrandom(param->priv, CURVE25519_LEN);
-	param->priv[0] &= 248;
-	param->priv[31] &= 127;
-	param->priv[31] |= 64;
-
-	curve25519_donna(param->pub, param->priv, basepoint);
+	dropbear_curve25519_scalarmult(param->pub, param->priv, basepoint);
 
 	return param;
 }
 
-void free_kexcurve25519_param(struct kex_curve25519_param *param)
-{
+void free_kexcurve25519_param(struct kex_curve25519_param *param) {
 	m_burn(param->priv, CURVE25519_LEN);
 	m_free(param);
 }
@@ -736,7 +732,7 @@ void kexcurve25519_comb_key(const struct kex_curve25519_param *param, const buff
 		dropbear_exit("Bad curve25519");
 	}
 
-	curve25519_donna(out, param->priv, buf_pub_them->data);
+	dropbear_curve25519_scalarmult(out, param->priv, buf_pub_them->data);
 
 	if (constant_time_memcmp(zeroes, out, CURVE25519_LEN) == 0) {
 		dropbear_exit("Bad curve25519");