merge of 6b56bdff53b47ae7366d93b496ce353d9e3753dc

and b68c53583ba80ad14fd0ba70ff26ea3dbd8e8823

--HG--
extra : convert_revision : 0a69485db882269664dcd5ec88e66b8ea9570855

TODO

@@ -4,9 +4,6 @@ Things which might need doing:
 
 - Make options.h generated from configure perhaps?
 
-- some sort of warning when blocking on random? (could be difficult,
-  investigate alarm() perhaps)
-
 - Improved queueing of unauthed connections
 
 - handle /etc/environment in AIX

cli-tcpfwd.c

@@ -94,7 +94,7 @@ static int cli_localtcp(unsigned int listenport, const char* remoteaddr,
 	TRACE(("enter cli_localtcp: %d %s %d", listenport, remoteaddr,
 				remoteport));
 
-	tcpinfo = (struct TCPListener*)m_malloc(sizeof(struct TCPListener*));
+	tcpinfo = (struct TCPListener*)m_malloc(sizeof(struct TCPListener));
 	tcpinfo->sendaddr = m_strdup(remoteaddr);
 	tcpinfo->sendport = remoteport;
 	tcpinfo->listenport = listenport;

random.c

@@ -51,6 +51,7 @@ static void readrand(unsigned char* buf, unsigned int buflen);
 
 static void readrand(unsigned char* buf, unsigned int buflen) {
 
+	static int already_blocked = 0;
 	int readfd;
 	unsigned int readpos;
 	int readlen;
@@ -93,6 +94,24 @@ static void readrand(unsigned char* buf, unsigned int buflen) {
 	/* read the actual random data */
 	readpos = 0;
 	do {
+		if (!already_blocked)
+		{
+			int ret;
+			struct timeval timeout;
+			fd_set read_fds;
+
+			timeout.tv_sec = 2; /* two seconds should be enough */
+			timeout.tv_usec = 0;
+
+			FD_ZERO(&read_fds);
+			FD_SET(readfd, &read_fds);
+			ret = select(readfd + 1, &read_fds, NULL, NULL, &timeout);
+			if (ret == 0)
+			{
+				dropbear_log(LOG_INFO, "Warning: Reading the random source seems to have blocked.\nIf you experience problems, you probably need to find a better entropy source.");
+				already_blocked = 1;
+			}
+		}
 		readlen = read(readfd, &buf[readpos], buflen - readpos);
 		if (readlen <= 0) {
 			if (readlen < 0 && errno == EINTR) {