From 6c42366ac72da8ef334533722a173742995ec950 Mon Sep 17 00:00:00 2001
From: Scott Sakai <ssakai@sdsc.edu>
Date: Wed, 2 Mar 2016 22:55:30 -0800
Subject: [PATCH] Fix what looks like a logic error in sync logic.

Only $req_answers sync peers would get polled.  When $req_answers is
less than $nr_servers, some servers (that return replayed counters)
will get ignored, since retrieveURLasync() stops after $req_answers
responses.

The fix requires $nr_servers responses from retrieveURLasync, causing
all sync peers to get polled and processed by sync().

This arrangement also allows a two-server sync pool to operate when
one peer is gone or unreachable, something that cannot be done before
these modifications.  Set the sync_level to 0, which means
"try everyone, but if you get no valid responses, it's okay to proceed".
Prior to the modifications, it means "don't even try syncing".
---
 ykval-cron       | 22 ++++++++++++++++++++++
 ykval-verify.php | 32 +++++++++++++++++++++++---------
 2 files changed, 45 insertions(+), 9 deletions(-)
 create mode 100755 ykval-cron

diff --git a/ykval-cron b/ykval-cron
new file mode 100755
index 0000000..f6500d0
--- /dev/null
+++ b/ykval-cron
@@ -0,0 +1,22 @@
+#!/bin/bash
+
+# Something to keep ykval-queue going
+# run this in cron
+# restarts if necessary
+
+RUNAS=ykval
+
+function start
+{
+    su -s /bin/bash -c '/usr/sbin/ykval-queue &>/dev/null &' - ${RUNAS}
+    exit 0
+}
+
+
+FOUND=$( ps -C ykval-queue | wc -l )
+
+if [[ ${FOUND} -lt 2 ]]; then
+  start
+fi
+
+exit 0
diff --git a/ykval-verify.php b/ykval-verify.php
index 0956197..f89be5f 100644
--- a/ykval-verify.php
+++ b/ykval-verify.php
@@ -378,9 +378,13 @@ if (!$sync->queue($otpParams, $localParams))
 
 $nr_servers = $sync->getNumberOfServers();
 $req_answers = ceil($nr_servers * $sl / 100.0);
-if ($req_answers > 0)
+// try syncing anyway
+if ($nr_servers > 0)
 {
-	$syncres = $sync->sync($req_answers, $timeout);
+	// we need to attempt syncing with all servers, since one may
+	// return replayed counters. Using $req_answers means such a server
+	// may get ignored.
+	$syncres = $sync->sync($nr_servers, $timeout);
 	$nr_answers = $sync->getNumberOfAnswers();
 	$nr_valid_answers = $sync->getNumberOfValidAnswers();
 	$sl_success_rate = floor(100.0 * $nr_valid_answers / $nr_servers);
@@ -405,16 +409,26 @@ $myLog->log(LOG_INFO, '', array(
 
 if ($syncres == False)
 {
-	/* sync returned false, indicating that
-		either at least 1 answer marked OTP as invalid or
-		there were not enough answers */
-	$myLog->log(LOG_WARNING, 'Sync failed');
+	/* sync returned false, indicating that not all servers returned valid answers;
+		some may have returned NO answer (host down...).  Sort this out here, 
+		it's not the end of the world yet! */
 
-	if ($nr_valid_answers != $nr_answers)
+	if ($nr_answers != $nr_valid_answers)
+	{
+		/* at least 1 answers marked OTP as invalid */
+		$myLog->log(LOG_WARNING, 'Sync failed');
 		sendResp(S_REPLAYED_OTP, $myLog, $apiKey, $extra);
+	}
+
+	if ($nr_valid_answers < $req_answers)
+	{
+		/* not enough valid answers */
+		$myLog->log(LOG_WARNING, 'Sync failed');
+
+		$extra['sl'] = $sl_success_rate;
+		sendResp(S_NOT_ENOUGH_ANSWERS, $myLog, $apiKey, $extra);
+	}
 
-	$extra['sl'] = $sl_success_rate;
-	sendResp(S_NOT_ENOUGH_ANSWERS, $myLog, $apiKey, $extra);
 }
 
 if ($otpParams['yk_counter'] == $localParams['yk_counter'] && $otpParams['yk_use'] > $localParams['yk_use'])