Comment 13 for bug 997217

The patch 0034 mentioned in comment #10 is applied in the xenial package 2.1.26.dfsg1-14build1, so what Roberto hit could be a different issue requiring a different fix.

Might have been this:
cyrus-sasl2 (2.1.26.dfsg1-15) unstable; urgency=medium

  * Add fix for auth_rimap infinite loop (hang) when IMAP server closes
    connection (Closes: #815208)

Patch is https://bugs.debian.org/cgi-bin/bugreport.cgi?att=1;bug=815208;filename=auth_rimap_socket_closed.patch;msg=5:
--- a/saslauthd/auth_rimap.c
+++ b/saslauthd/auth_rimap.c
@@ -494,7 +494,7 @@
         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 {
@@ -607,7 +607,7 @@
         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 {