https://bugzilla.cyrusimap.org/show_bug.cgi?id=3920

--- saslauthd/auth_rimap.orig	2016-02-19 21:55:07.000000000 -0500
+++ saslauthd/auth_rimap.c	2016-02-19 21:55:36.000000000 -0500
@@ -383,7 +383,7 @@
         while( select (fds, &perm, NULL, NULL, &timeout ) >0 ) {
            if ( FD_ISSET(s, &perm) ) {
               ret = read(s, rbuf+rc, sizeof(rbuf)-rc);
-              if ( ret<0 ) {
+              if ( ret<=0 ) {
                  rc = ret;
                  break;
               } else {
@@ -496,7 +496,7 @@
         while( select (fds, &perm, NULL, NULL, &timeout ) >0 ) {
            if ( FD_ISSET(s, &perm) ) {
               ret = read(s, rbuf+rc, sizeof(rbuf)-rc);
-              if ( ret<0 ) {
+              if ( ret<=0 ) {
                  rc = ret;
                  break;
               } else {