Handle recursion better, caused by ACLs.fix_receive_bombout

Issue debugged by Todd Lyons, this fix from me.

1 files changed, 26 insertions, 8 deletions

diff --git a/src/src/receive.c b/src/src/receive.c
index e0c1c7393..56de9fbb3 100644
--- a/src/src/receive.c
+++ b/src/src/receive.c
@@ -286,32 +286,50 @@ Returns:     it doesn't
 void
 receive_bomb_out(uschar *reason, uschar *msg)
 {
+  static BOOL already_bombing_out;
+/* The smtp_notquit_exit() below can call ACLs which can trigger recursive
+timeouts, if someone has something slow in their quit ACL.  Since the only
+things we should be doing are to close down cleanly ASAP, on the second
+pass we also close down stuff that might be opened again, before bypassing
+the ACL call and exiting. */
+
 /* If spool_name is set, it contains the name of the data file that is being
 written. Unlink it before closing so that it cannot be picked up by a delivery
 process. Ensure that any header file is also removed. */
 
-if (spool_name[0] != 0)
+if (spool_name[0] != '\0')
   {
   Uunlink(spool_name);
   spool_name[Ustrlen(spool_name) - 1] = 'H';
   Uunlink(spool_name);
+  spool_name[0] = '\0';
   }
 
 /* Now close the file if it is open, either as a fd or a stream. */
 
-if (data_file != NULL) (void)fclose(data_file);
-  else if (data_fd >= 0) (void)close(data_fd);
+if (data_file != NULL)
+  {
+  (void)fclose(data_file);
+  data_file = NULL;
+} else if (data_fd >= 0) {
+  (void)close(data_fd);
+  data_fd = -1;
+  }
 
 /* Attempt to close down an SMTP connection tidily. For non-batched SMTP, call
 smtp_notquit_exit(), which runs the NOTQUIT ACL, if present, and handles the
 SMTP response. */
 
-if (smtp_input)
+if (!already_bombing_out)
   {
-  if (smtp_batched_input)
-    moan_smtp_batch(NULL, "421 %s - message abandoned", msg);  /* No return */
-  smtp_notquit_exit(reason, US"421", US"%s %s - closing connection.",
-    smtp_active_hostname, msg);
+  already_bombing_out = TRUE;
+  if (smtp_input)
+    {
+    if (smtp_batched_input)
+      moan_smtp_batch(NULL, "421 %s - message abandoned", msg);  /* No return */
+    smtp_notquit_exit(reason, US"421", US"%s %s - closing connection.",
+      smtp_active_hostname, msg);
+    }
   }
 
 /* Exit from the program (non-BSMTP cases) */