[exim-dev] [Bug 3030] New: "null conn-context pointer" logge…

https://bugs.exim.org/show_bug.cgi?id=3030

            Bug ID: 3030
           Summary: "null conn-context pointer" logged in smtp_out.c
           Product: Exim
           Version: 4.97
          Hardware: x86
                OS: Linux
            Status: NEW
          Severity: bug
          Priority: medium
         Component: Transports
          Assignee: unallocated@???
          Reporter: pdw@???
                CC: exim-dev@???

https://github.com/Exim/exim/blob/master/src/src/smtp_out.c#L569

The above code has a null guard and an "XXX" comment suggesting that it wasn't
known what was triggering the null.

I can reliably reproduce this with a recipient verify that does a DANE check
for a specific host which returns SERVFAIL for the TLSA lookup.

I haven't quite pinned down what goes wrong, but I think it handles the DNS
lookup failure incorrectly and attempts to close an SMTP connection that was
never opened.

The config has this:

acl_check_rcpt:

  deny
    !verify = recipient/callout=10s

and:

remote_smtp:
driver = smtp
hosts_require_dane = *

Obviously this isn't a serious bug, as the null guard masks the issue, but I
thought I'd provide context on what was triggering it after we tripped over the
segfault in production on an older version of Exim.

--
You are receiving this mail because:
You are on the CC list for the bug.

--
## subscription configuration (requires account):
## https://lists.exim.org/mailman3/postorius/lists/exim-dev.lists.exim.org/
## unsubscribe (doesn't require an account):
## exim-dev-unsubscribe@???
## Exim details at http://www.exim.org/
## Please use the Wiki with this list - http://wiki.exim.org/