Re: [PATCH] mail/alpine: unable to send mail in default install

see kern_exec.c line 600

-- 

  Sent from a phone, apologies for poor formatting.

On 29 April 2025 21:00:26 Lloyd <ng2d68@proton.me> wrote:

Sorry for the duplicate message but I have some more information to share:

I instrumented some fake sendmail binaries/scripts to I can insert myself

in between and execute a ktrace. Note that below the "/usr/sbin/send-mail"

is just a symlink to smtpctl to trigger "sendmail compat mode" of smtpd.

Unfortunately in both cases below this is the entire ktrace. I've already

eliminated mailwrapper(8) as the source of any issues as it successfully

calls smtpctl and that's where the hang is happening. Below two examples

show a call to smtpctl with default Alpine args and a forced "-t" arg:

14906 ktrace   RET   ktrace 0

14906 ktrace   CALL  execve(0x6fd7f687e0ff,0x6fd7f687df88,0x6fd7f687dfb0)

14906 ktrace   NAMI  "/usr/sbin/send-mail"

14906 ktrace   ARGS  

 [0] = "/usr/sbin/send-mail"

 [1] = "-bs"

 [2] = "-odb"

 [3] = "-oem"

18856 ktrace   RET   ktrace 0

18856 ktrace   CALL  execve(0x77fb458a4f7f,0x77fb458a4e18,0x77fb458a4e30)

18856 ktrace   NAMI  "/usr/sbin/send-mail"

18856 ktrace   ARGS  

 [0] = "/usr/sbin/send-mail"

 [1] = "-t"

Regards

Lloyd

On Tuesday, April 29th, 2025, Lucas Gabriel Vuotto wrote:

Hey Lloyd,

On Tue, Apr 29, 2025 at 02:00:17AM +0000, Lloyd wrote:

There is a bug in Alpine whereby out of the box it is unable to send email on

an OpenBSD box, even locally. By default, sending a message in unconfigured

Alpine will fork out to sendmail(8) which hangs for some unknown reason and

the sendmail wrapper process needs to be killed. Receiving mail works fine.

Running /usr/sbin/sendmail -t < ~/dead.letter against the abandoned message

works fine, so the interface between Alpine and the sendmail wrapper is

broken.

I ran a ktrace but couldn't find anything substantiative. Rather than debug

this further, there is a much simpler patch to get Alpine working in the

default install. The below change sets the value of smtp-server to localhost

in the file which gets copied to /etc/pine.conf on installation. With this

variable set, Alpine connects to the local smtpd over TCP rather than using

the sendmail(8) utility, if the user has no smtp server defined.

/etc/pine.conf is overridden by the user's ~/.pinerc so this should be a

non-destructive change that will not impact anything but an unconfigured

installation which falls back to using sendmail(8), which does not work.

If it did work, then I believe --with-smtp-msa-flags=-t should be set in

the Makefile as well since the hard-coded defaults pass bogus flags to

sendmail(8). This didn't work either so it really doesn't matter, I believe

the issue lies somewhere in the threading mechanism and how it forks out

to sendmail. It's possible a prior security-related change broke something.

This issue dates back to at least OpenBSD 6.8:

https://marc.info/?l=openbsd-misc&m=161141614219034&w=2

I'm not an alpine user, but got curious about this issue. Would you mind

sharing the bits of `ktrace -di alpine` related to exec functions with

me? It's important you share only those bits, as ktrace output might

include data like passwords.

For the record, I verified that adding --with-smtp-msa-flags=-t does

indeed set it in the code, so that should be working.

Lucas