Re: [PATCH log-tracker] handle smtp filter message: prevent panicking with non-standard output

[Thomas Lamprecht <t.lamprecht@proxmox.com>]

On 10/06/2026 15:15, Dominik Csapak wrote:
> Currently a custom checkscript can print it's output into the syslog
> under the guise of the pmg-smtp-filter unit, so it will picked up
> by the log tracker. In case there is a line with a delimiter and nothing
> after it, every thing before is detected as a qid but the remaining
> message only contains the delimiter.
> 
> Prevent the panicking here by checking its length beforehand.
> 
> While the real fix is either to prevent custom check scripts to output
> to syslog, or to prefix it with something we can filter away here,
> protecting against malformed output still makes sense.
> 
> Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
> ---
>  src/main.rs | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/src/main.rs b/src/main.rs
> index efdfd30..4787a36 100644
> --- a/src/main.rs
> +++ b/src/main.rs
> @@ -115,6 +115,11 @@ fn handle_pmg_smtp_filter_message(msg: &[u8], parser: &mut Parser, complete_line
>          Some((q, m)) => (q, m),
>          None => return,
>      };
> +    if data.len() < 2 {
> +        // after the QID there is no separator and space, so it can't be a proper smtp-filter
> +        // message. It's possibly output from a custom check script or a malformed log line.

this comment confuses me, reads like a separator and space after a QID
being wrong, but it's what's expected, with the &data[2..]; IMO no comment
would be required, but short one can be fine - will squash that in on applying.

> +        return;
> +    }
>      // skip ': ' following the QID
>      let data = &data[2..];
>