--- a/svr-kex.c	Thu Mar 21 23:28:59 2019 +0800
+++ b/svr-kex.c	Fri Jun 26 21:07:34 2020 +0800
@@ -38,13 +38,15 @@
 #include "gensignkey.h"
 
 static void send_msg_kexdh_reply(mp_int *dh_e, buffer *ecdh_qs);
+#if DROPBEAR_EXT_INFO
+static void send_msg_ext_info(void);
+#endif
 
 /* Handle a diffie-hellman key exchange initialisation. This involves
  * calculating a session key reply value, and corresponding hash. These
  * are carried out by send_msg_kexdh_reply(). recv_msg_kexdh_init() calls
  * that function, then brings the new keys into use */
 void recv_msg_kexdh_init() {
-
 	DEF_MP_INT(dh_e);
 	buffer *ecdh_qs = NULL;
 
@@ -86,6 +88,14 @@
 	}
 
 	send_msg_newkeys();
+
+#if DROPBEAR_EXT_INFO
+	/* Only send it following the first newkeys */
+	if (!ses.kexstate.donesecondkex && ses.allow_ext_info) {
+		send_msg_ext_info();
+	}
+#endif
+
 	ses.requirenext = SSH_MSG_NEWKEYS;
 	TRACE(("leave recv_msg_kexdh_init"))
 }
@@ -123,6 +133,11 @@
 			fn = ECDSA_PRIV_FILENAME;
 			break;
 #endif
+#if DROPBEAR_ED25519
+		case DROPBEAR_SIGNKEY_ED25519:
+			fn = ED25519_PRIV_FILENAME;
+			break;
+#endif
 		default:
 			dropbear_assert(0);
 	}
@@ -219,7 +234,8 @@
 			{
 			struct kex_curve25519_param *param = gen_kexcurve25519_param();
 			kexcurve25519_comb_key(param, ecdh_qs, svr_opts.hostkey);
-			buf_putstring(ses.writepayload, (const char*)param->pub, CURVE25519_LEN);
+
+			buf_putstring(ses.writepayload, param->pub, CURVE25519_LEN);
 			free_kexcurve25519_param(param);
 			}
 			break;
@@ -228,7 +244,7 @@
 
 	/* calc the signature */
 	buf_put_sign(ses.writepayload, svr_opts.hostkey, 
-			ses.newkeys->algo_hostkey, ses.hash);
+			ses.newkeys->algo_signature, ses.hash);
 
 	/* the SSH_MSG_KEXDH_REPLY is done */
 	encrypt_packet();
@@ -236,3 +252,20 @@
 	TRACE(("leave send_msg_kexdh_reply"))
 }
 
+#if DROPBEAR_EXT_INFO
+/* Only used for server-sig-algs on the server side */
+static void send_msg_ext_info(void) {
+	TRACE(("enter send_msg_ext_info"))
+
+	buf_putbyte(ses.writepayload, SSH_MSG_EXT_INFO);
+	/* nr-extensions */
+	buf_putint(ses.writepayload, 1);
+
+	buf_putstring(ses.writepayload, SSH_SERVER_SIG_ALGS, strlen(SSH_SERVER_SIG_ALGS));
+	buf_put_algolist_all(ses.writepayload, sigalgs, 1);
+	
+	encrypt_packet();
+
+	TRACE(("leave send_msg_ext_info"))
+}
+#endif