more random patches. who knows.

[patches.git] / dropbear-0.45-urandom.patch

--- dropbear-0.45.orig/options.h	2005-03-08 14:43:07.000000000 -0500
+++ dropbear-0.45/options.h	2005-03-08 14:44:41.000000000 -0500
@@ -148,6 +148,10 @@
 /* prngd must be manually set up to produce output */
 /*#define DROPBEAR_PRNGD_SOCKET "/var/run/dropbear-rng"*/
 
+/* If the normal random source would block for a while, fall back to 
+ * the urandom source so that connections don't hang forever. */
+#define DROPBEAR_URANDOM_DEV "/dev/urandom"
+
 /* Specify the number of clients we will allow to be connected but
  * not yet authenticated. After this limit, connections are rejected */
 #ifndef MAX_UNAUTH_CLIENTS
diff -ur dropbear-0.45.orig/random.c dropbear-0.45/random.c
--- dropbear-0.45.orig/random.c	2005-03-08 14:43:07.000000000 -0500
+++ dropbear-0.45/random.c	2005-03-08 14:57:31.000000000 -0500
@@ -57,9 +57,14 @@
 	struct sockaddr_un egdsock;
 	char egdcmd[2];
 #endif
+	mode_t readmode = O_RDONLY;
+#ifdef DROPBEAR_URANDOM_DEV
+	unsigned int readtries = 0;
+	readmode |= O_NONBLOCK;
+#endif
 
 #ifdef DROPBEAR_RANDOM_DEV
-	readfd = open(DROPBEAR_RANDOM_DEV, O_RDONLY);
+	readfd = open(DROPBEAR_RANDOM_DEV, readmode);
 	if (readfd < 0) {
 		dropbear_exit("couldn't open random device");
 	}
@@ -97,6 +102,24 @@
 			if (readlen < 0 && errno == EINTR) {
 				continue;
 			}
+#ifdef DROPBEAR_URANDOM_DEV
+			/* if the main random source blocked, lets retry a few times, 
+			 * but then give up and try a constant random source. */
+			if (readlen < 0 && errno == EAGAIN) {
+				++readtries;
+				if (readtries < 5) {
+					sleep(1);
+					continue;
+				} else if (readtries == 5) {
+					close (readfd);
+					readfd = open(DROPBEAR_URANDOM_DEV, readmode);
+					if (readfd < 0) {
+						dropbear_exit("couldn't open secondary random device");
+					}
+					continue;
+				}
+			}
+#endif
 			dropbear_exit("error reading random source");
 		}
 		readpos += readlen;