Bug#1082905: exim4-daemon-light: crash at dkim.c:745 when dkim_private_key is not readable by exim4 process

[Andreas Metzler]

On 2024-09-28 Germano Leichsenring <germano.leichsenring at gmail.com> wrote:
> Package: exim4-daemon-light
> Version: 4.98-1
> Severity: normal
> X-Debbugs-Cc: germano.leichsenring at gmail.com

> Dear Maintainer,


>    * What led up to the situation?
> Fresh install of exim4 with DKIM.
>    * What exactly did you do (or not do) that was effective (or
>      ineffective)?
> I've followed upstream instructions to setup DKIM.
> https://exim.org/exim-html-4.93/doc/html/spec_html/ch-dkim_spf_and_dmarc.html
>  Note, the command below creates the private key file with permissions 600.
> $ openssl genpkey -algorithm ed25519 -out dkim_ed25519.private

>    * What was the outcome of this action?
>  Accordingly, exim4 process crashed and left a stacktrace in the paniclog.
> 2024-09-28 10:33:46 1suML0-00000001hFO-444S SIGSEGV (fault address: 0x55fac168b1d0)
[...]
>  After looking at the faulty line (dkim.c:745) I've realized that the file was not readable.

>    * What outcome did you expect instead?
>  As a minimum I'd expect no crashes, and maybe a warning or error in this case.
[...]

Hello Germano,

I have just uploaded 4.98-2 which features Jeremy's patch
(https://bugs.exim.org/show_bug.cgi?id=3116). Could you please
doublecheck whether this fixes the crash for you?

The package should be available for downlad on the mirrors in about 12
hors.

TIA, cu Andreas