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Announcing Notqmail

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Re: Announcing Notqmail

#41
post #31
post #30

Earlier quoted context omitted.

Road warriors with Thunderbird may need SMTP authentication, but most people do relaying with just IP authentication just fine.

Aside of the fact that I doubt your "most people" assertion here, it's beside the point that I was trying to make which is that a CVE affecting a feature of Postfix that qmail doesn't have to begin with is not a fair mark against postfix. Because if you disable a feature you don't use, you won't be affected by the vulnerability. If you use smtp authentication, you're not running djb's code and all advantages of djb's…

> it's beside the point that I was trying to make which is that a CVE affecting a feature of Postfix that qmail doesn't have to begin with is not a fair mark against postfix.

I disagree. It is a fair mark against postfix if (as I claim) most users really don't need it.

Here's my reasoning to that point:

I think most email end-users either use their ISPs mail settings (who know who they are and don't need authentication), or webmail (which doesn't use SMTP for relaying anyway), or outlook (which doesn't need SMTP at all). Fastmail is becoming more popular and it doesn't need SMTP either. The end-users who remain are either business users (who could use a VPN which is better than SMTP AUTH in every way), and nutters with vanity domains.

If that's contended, and note I do believe there are probably end users who are actually still manually entering SMTP AUTH settings into email clients, but I would struggle to believe they're the majority and would need evidence.

Meanwhile on the enterprise, pretty much every machine in every enterprise environment I've ever worked in has been set up for local relay. Again, if you think they're all using SMTP AUTH I'd need to see evidence.

> If you use smtp authentication, you're not running djb's code and all advantages of djb's code are moot

Do you actually believe that if you apt-get install postfix that you don't have any of the advantages of postfix's development processes?

I'm not sure I can engage with that. It's like saying running linux invalidates "all advantages of djb's code" simply because you're (sometimes) not running his code (e.g. when you're in a syscall). Madness runs down that way.

For what it's worth, most of the qmail smtpd patches I've seen to add SMTP AUTH (including the one I wrote nearly twenty years ago) are sensible, integrate well with the rest of qmail. You might not get djb's warrantee, but I can't believe you gain nothing by starting from a solid foundation.

Re: Announcing Notqmail

#42
post #41
post #31

Earlier quoted context omitted.

Aside of the fact that I doubt your "most people" assertion here, it's beside the point that I was trying to make which is that a CVE affecting a feature of Postfix that qmail doesn't have to begin with is not a fair mark against postfix. Because if you disable a feature you don't use, you won't be affected by the vulnerability. If you use smtp authentication, you're not running djb's code and all advantages of djb's…

> it's beside the point that I was trying to make which is that a CVE affecting a feature of Postfix that qmail doesn't have to begin with is not a fair mark against postfix. I disagree. It is a fair mark against postfix if (as I claim) most users really don't need it. Here's my reasoning to that point: I think most email end-users either use their ISPs mail settings (who know who they are and don't need authenticati…

>I disagree. It is a fair mark against postfix if (as I claim) most users really don't need it.

if they don't need it, they won't be affected by that vulnerability because it won't be active.

>Meanwhile on the enterprise, pretty much every machine in every enterprise environment I've ever worked in has been set up for local relay.

In every enterprise setup I have seen, local relay was still protected using SMTP-AUTH for accounting purposes.

Plus in case of end-users, many ISPs still provide SMTP for mail delivery, all of whom need to support SMTP auth. That includes Fastmail and Gmail.

>but I can't believe you gain nothing by starting from a solid foundation.

Of course you do. But saying "Postfix is worse because it had a security vulnerability in a component that qmail doesn't even support" is unfair to postfix.

If you are running qmail with a custom patch then that custom patch will for sure have been exposed to less scrutiny than Postfix proper. It's not valid to extend the scrutiny given to vanilla qmail to all of the custom patches.

Re: Announcing Notqmail

#43
post #30
post #29

Earlier quoted context omitted.

> CVE-2011-1720 and CVE-2008-2936 are examples of postfix vulns no one has found, or reasonably expects to find, in djb code. CVE-2011-1720 is related to SMTP authentication which qmail doesn't support out-of-the box. So. Yes you're right: You don't find that vulnerability in qmail because qmail doesn't have that feature. Can you run an SMTP server without authentication these days? Not if you have users using you as…

Road warriors with Thunderbird may need SMTP authentication, but most people do relaying with just IP authentication just fine.

If you think an IP address is a reliable identifier, your opinions on security have no value.

Re: Announcing Notqmail

#44
post #43
post #30

Earlier quoted context omitted.

Road warriors with Thunderbird may need SMTP authentication, but most people do relaying with just IP authentication just fine.

If you think an IP address is a reliable identifier, your opinions on security have no value.

While you and I agree that Parent is incorrect, let's not resort to personal attacks.

Re: Announcing Notqmail

#45
post #23
post #19

Earlier quoted context omitted.

Not that I disagree, but to inject some clarity: Python would be a perfect fit too. The major MTAs are written in C not because they need to be, but because C was the only serious option in the mid-late 1990s. Any modern language would work.

If all you care about it is memory safety, sure. If you also care about performance, I'd be skeptical of such claims.

I used to run Qmail on a system that handled ~2m users. The main limitation was IO capacity. Today the M.2 NVMe SSD in my laptop can do substantially faster IO than the rack sized storage array we used for that mail system.

If you're building a competitor for Gmail or Hotmail, then maybe that performance difference will matter. For almost everyone else it's largely irrelevant.

EDIT: I'm confused by the downvotes for this. If someone has practical experience that suggests that performance is a real concern for this type of use, I'd love to hear about it. For my part I built and ran such a system for a couple of years, and spent a lot of time looking at the performance constraints. CPU usage just was not a factor even on ~20 year old (by now) hardware, running on 4-5 machines where the beefiest one had either 2 or 4 cores. All our optimization efforts consistently went on trading increased CPU usage for reducing IO use, because that is where the bottlenecks were. That's been reinforced with other mail systems I've run over the years, including large scale mail processing with PHP (not my choice) - every such system I've seen have been IO constrained rather than CPU constrained.

Re: Announcing Notqmail

#46
post #43
post #30

Earlier quoted context omitted.

Road warriors with Thunderbird may need SMTP authentication, but most people do relaying with just IP authentication just fine.

If you think an IP address is a reliable identifier, your opinions on security have no value.

[deleted]

Re: Announcing Notqmail

#47
post #42
post #41

Earlier quoted context omitted.

> it's beside the point that I was trying to make which is that a CVE affecting a feature of Postfix that qmail doesn't have to begin with is not a fair mark against postfix. I disagree. It is a fair mark against postfix if (as I claim) most users really don't need it. Here's my reasoning to that point: I think most email end-users either use their ISPs mail settings (who know who they are and don't need authenticati…

>I disagree. It is a fair mark against postfix if (as I claim) most users really don't need it. if they don't need it, they won't be affected by that vulnerability because it won't be active. >Meanwhile on the enterprise, pretty much every machine in every enterprise environment I've ever worked in has been set up for local relay. In every enterprise setup I have seen, local relay was still protected using SMTP-AUTH…

> saying "Postfix is worse because it had a security vulnerability in a component that qmail doesn't even support" is unfair to postfix.

Ok, well that's your opinion, and hopefully now you at least know why I have mine.

I can't imagine forgiving Microsoft for all those AD/SMB and explorer CVE just because Linux doesn't support those things, but it's not really that important to me.

> In every enterprise setup I have seen, local relay was still protected using SMTP-AUTH for accounting purposes.

I have no idea what you mean by "accounting purposes" -- it sounds like you're talking about users relaying and not machines relaying.

There is no way you'd get a SOC2 (or SSAE/SOC1) if you used SMTP auth to protect local relays, so perhaps we are talking about different things when we say "enterprise".

> If you are running qmail with a custom patch then that custom patch will for sure have been exposed to less scrutiny than Postfix proper.

I'm still not sure you can have it both ways. Why is it when Debian patches postfix that it's still (in your mind) "postfix proper" but when I download a well-distributed and discussed patch from a mailing list, and read it myself, that you somehow think I'm at higher risk?

Re: Announcing Notqmail

#48
post #47
post #42

Earlier quoted context omitted.

>I disagree. It is a fair mark against postfix if (as I claim) most users really don't need it. if they don't need it, they won't be affected by that vulnerability because it won't be active. >Meanwhile on the enterprise, pretty much every machine in every enterprise environment I've ever worked in has been set up for local relay. In every enterprise setup I have seen, local relay was still protected using SMTP-AUTH…

> saying "Postfix is worse because it had a security vulnerability in a component that qmail doesn't even support" is unfair to postfix. Ok, well that's your opinion, and hopefully now you at least know why I have mine. I can't imagine forgiving Microsoft for all those AD/SMB and explorer CVE just because Linux doesn't support those things, but it's not really that important to me. > In every enterprise setup I have…

>it sounds like you're talking about users relaying and not machines relaying

there is such a thing as machine- or even application-specific accounts that can be terminated or their credentials rotated.

Even better; you could use something like Vault (https://www.vaultproject.io/) to manage such application-specific credentials.

All of this is much better than relying on IP addresses never changing and never being reused.

>Why is it when Debian patches postfix that it's still (in your mind) "postfix proper" but when I download a well-distributed and discussed patch from a mailing list, and read it myself, that you somehow think I'm at higher risk?

I never said it was postfix proper. It really isn't.

Debian is known to f'up the security of its packages. But it's my hope that distributors have a better equipped security team and bigger exposure compared to some guy putting a patch on some website.

Debian also has a proper security update process that makes sure that patches go out to users quickly and painlessly. And because Debian is big enough, it's usually included in embargoed security vulnerability reports, so usually a patch will be out and sometimes even deployed by the time the vulnerability is known.

But the relative security of Debian-maintained postfix vs. Debian-maintained custom-patched qmail is the same as postfix proper vs custom-patched qmail.

However, vanilla whatever, in my opinion is superior to custom-patched whatever. And while postfix is usable vanilla, qmail isn't. It was bordering unusable back in the 90ies and it definitely is unusable nowadays.

qmail doesn't support TLS, it doesn't support spf, much less domainkeys or dmarc. It doesn't (as we're talking about) support SMTP auth, it doesn't support ipv6. It doesn't support any other common anti spam measures like greylisting or rbl checks, nor does it support a plugin system that would allow for easy plugging them in.

Heck, it doesn't even support rejecting mail at SMTP time so it's one of the worst offenders for backscatter which is one of the big annoyances for mail admins.

At this point, an unpatched qmail is as useful in fulfilling MTA roles as a closed port 25 is (which would totally be safer than both qmail and postfix)

Hence my assertion that everybody is running a patched qmail and none of these patches ever enjoyed the same scrutiny as even the security abominations that are sendmail and exim.

And worse: None of these patches were ever reviewed for side-effects of arbitrarily combining them.

Nearly every custom patch was made against a vanilla qmail because there is no central project to manage these patches. So every site runs a different version of qmail, none of them vetted at all for security.

This is a mess and we should really discourage this rather than dreaming of long-gone times where vanilla qmail at least was useful to a minor degree.

Partially-related update: I just looked at the qmail code: This thing is written in K&R style C and sometimes uses single-character variable and function names. I would argue nobody but djb can actually safely make changes to this code-base. This is all from a bygone age. Let it rest.

Re: Announcing Notqmail

#49
post #4

I used qmail for about ten years. It was remarkably good from a sysadmin's perspective: - the config system mostly used the name of a directory where lots of software would use a filename (qmail.ini => /var/qmail/conf), the name of a file where other software would use a variable name, and the contents of the file as the value of the variable. This is really, really easy to read and write without writing a parsing li…

I liked a lot of things about qmail, but I found it annoying as a sysadmin, like in the 1.07 days, because you had to do all this patching. I eventually wrote a script that would take all the sources and patches that one needed to run a reasonable mail server, and turn them into an RPM that could be installed, because I couldn't just provide the patched, resulting RPMs. There were a lot of great things about qmail. I…

Yes, for a long time it's been the case that to run qmail you have to really really want to run qmail. That's why I put so much effort for so many years into cross-platform packages of qmail in pkgsrc, and that's why we have "Meeting all common needs with OS-provided packages" as an explicit goal for the notqmail project.

Re: Announcing Notqmail

#50
post #14

Earlier quoted context omitted.

They can’t, unless qmail has been configured to know they control mail for domain.tld. The admin configuration mechanism for this (control/virtualdomains) is simple and powerful.

Sorry I'm confused. If your mail server is setup for control of a domain (e.g. domain.tld), then what stops someone from putting postmaster@domain.tld in this .qmail file?

People can put whatever they want in their own .qmail files. That doesn't affect anything unless qmail believes those .qmail files are relevant to what it's delivering. A user controls .qmail files for a domain if and only if an admin has configured qmail to delegate that domain to that user.
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