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

[Dominik Csapak <d.csapak@proxmox.com>]

On 6/10/26 3:51 PM, Thomas Lamprecht wrote:
> 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.

ah ok sorry, i wanted to express that this is missing in this branch,
so after the length check shows it's shorter

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