1 files changed, 21 insertions, 23 deletions

diff --git a/common-session.c b/common-session.c
index e8dc650..a16d1f9 100644
--- a/common-session.c
+++ b/common-session.c
@@ -143,27 +143,21 @@ void session_loop(void(*loophandler)()) {
 			dropbear_exit("Terminated by signal");
 		}
 		
-		if (val < 0) {
-			if (errno == EINTR) {
-				/* This must happen even if we've been interrupted, so that
-				 * changed signal-handler vars can take effect etc */
-				if (loophandler) {
-					loophandler();
-				}
-				continue;
-			} else {
-				dropbear_exit("Error in select");
-			}
+		if (val < 0 && errno != EINTR) {
+			dropbear_exit("Error in select");
+		}
+
+		if (val <= 0) {
+			/* If we were interrupted or the select timed out, we still
+			 * want to iterate over channels etc for reading, to handle
+			 * server processes exiting etc. 
+			 * We don't want to read/write FDs. */
+			FD_ZERO(&writefd);
+			FD_ZERO(&readfd);
 		}
 
 		/* check for auth timeout, rekeying required etc */
 		checktimeouts();
-		
-		if (val == 0) {
-			/* timeout */
-			TRACE(("select timeout"))
-			continue;
-		}
 
 		/* process session socket's incoming/outgoing data */
 		if (ses.sock != -1) {
@@ -229,13 +223,11 @@ void session_identification() {
 	/* write our version string, this blocks */
 	if (atomicio(write, ses.sock, LOCAL_IDENT "\r\n",
 				strlen(LOCAL_IDENT "\r\n")) == DROPBEAR_FAILURE) {
-		dropbear_exit("Error writing ident string");
+		ses.remoteclosed();
 	}
 
-	/* We allow up to 9 lines before the actual version string, to
-	 * account for wrappers/cruft etc. According to the spec only the client
-	 * needs to handle this, but no harm in letting the server handle it too */
-	for (i = 0; i < 10; i++) {
+    /* If they send more than 50 lines, something is wrong */
+	for (i = 0; i < 50; i++) {
 		len = ident_readln(ses.sock, linebuf, sizeof(linebuf));
 
 		if (len < 0 && errno != EINTR) {
@@ -252,13 +244,19 @@ void session_identification() {
 
 	if (!done) {
 		TRACE(("err: %s for '%s'\n", strerror(errno), linebuf))
-		dropbear_exit("Failed to get remote version");
+		ses.remoteclosed();
 	} else {
 		/* linebuf is already null terminated */
 		ses.remoteident = m_malloc(len);
 		memcpy(ses.remoteident, linebuf, len);
 	}
 
+    /* Shall assume that 2.x will be backwards compatible. */
+    if (strncmp(ses.remoteident, "SSH-2.", 6) != 0
+            && strncmp(ses.remoteident, "SSH-1.99-", 9) != 0) {
+        dropbear_exit("Incompatible remote version '%s'", ses.remoteident);
+    }
+
 	TRACE(("remoteident: %s", ses.remoteident))
 
 }