Hi, On 7/26/26 18:29, Andreas Metzler wrote:
Can we create a systemd service that sends a mail, and has its own lifetime and permissions?
afaiui the important thing when interacting with a local exim is to *not* submit mail from a systemd service via the /usr/sbin/sendmail interface. This avoids having the exim and the respective service in the same cgroup. Submitting by smtp should work avoid this.
/usr/bin/sendmail is a Unix interface. It assumes Unix semantics: - runs as the calling user - has access to the user home directory- additional privileges are defined by the sysadmin through setuid. The distribution provides a default
- background tasks can lingerSystemd explicitly does not want to follow Unix semantics, so we cannot assume that Unix semantics will hold unless there is an explicit mechanism for them, and we are seeing breakage precisely where we're using a Unix tool inside a non-Unix environment.
The answer to that isn't to hack something to restore enough of the Unix semantics to make it work for another release, but to explicitly define an interface that does not rely on implementation details of a non-hardened environment, because that is not supportable.
So: if there should be a way for a program to send mail, there needs to be a dbus service, with proper authorization through the policy framework.
Simon
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