Comment 8 for bug 1927755

I am able to reproduce this on bionic, but not on focal or newer.

The issue appears to be that in newer code, a bitmask structure was introduced to hold various boolean settings in the application:

  ## globals.c
  struct global_flags f =
  {
    .acl_temp_details = FALSE,
 ...
 .running_in_test_harness = FALSE,
 ...
  };

However, the exim4 code in bionic predates this refactor, and running_in_test_harness is a simple global.

Patch 0051-CVE-2020-28007-Link-attack-in-Exim-s-log-directory.patch adds code that assumes the f global exists:

+/* Write the contents to the history file */
+DEBUG(D_receive)
+ debug_printf("DMARC logging history data for opendmarc reporting%s\n",
+ (host_checking || f.running_in_test_harness) ? " (not really)" : "");
+if (host_checking || f.running_in_test_harness)
+ {
+ DEBUG(D_receive)
+ debug_printf("DMARC history data for debugging:\n%s", history_buffer);
+ }

So yeah, the patch from comment #3 should be applied to patch 0051 (or added as a followup fixup patch). But this is only needed for bionic.