It is a difference of security. As one example, Debian used to be more lenient on allowing packages to vendor and statically link libraries. Around 20 years ago, an important zlib vulnerability was found that could be exploited through malicious compressed data. Rather than just pushing out a fixed zlib package, the package maintainers had to scan the repos for all copies and versions of the zlib source, patch them individually, and test each package. To make matters worse, some packages had modified versions of zlib that needed custom variants of the patch. This is a ton of work to ask of a small group of volunteers, and leaves users vulnerable for longer.

Vendored copies of libraries is a special case that's unrelated to this discussion. This discussion is about a distro whose packages dynamically link to the distro's zlib package vs a distro whose packages statically link to the distro's zlib package.

I don't think vendored copies are a special case or unrelated. For example, Debian does not allow vendored copies of libs. You have to use the version provided by the system, even if it's out of date or not the one you prefer. This explicit disallowing of different code versions also greatly improves security and threat response.

This recently (ish) bit hyprland, because they used a pinned version of wlroots, and the version of wlroots on Debian wouldn't work. And they couldn't just dynamically link to this pinned wlroots because that's still not around.

If the version of wlroots in Debian, hypothetically, contains a vulnerability, then only one change is needed instead of two.

I would argue if you allow static linking you implicitly encourage vendoring. I can't imagine such a distro where static linking is allowed, but there are 0 packages which use different lib commits.

> This is a ton of work to ask of a small group of volunteerss and leaves users vulnerable for longer.

Perhaps consider purchasing a support contract if people's charity endangers your users.

The build time is pretty significant actually. E.g. NixOS takes this to the extreme and always rebuilds packages if their dependencies change. It can take days to rebuild affected packages, and you typically can't easily update in the meantime. This is worse if the rebuild breaks something since someone will have to fix or revert that before it can succeed.

For non-security updates, they can do the rebuild in a branch (staging) so it's non-blocking, but you will feel the pain on a security update.

In practice, users will apply a config mitigation if available or "graft" executables against an updated lib using system.replaceDependencies, which basically search and replaced the built artifacts to use a different file path.

True. I'm involved in Alpine, postmarketOS and OpenSUSE packaging and I've seen builders of the first two become noticeably slow on mass rebuilds. OpenSUSE tends to be fine, but it has a lot of builders so that's probably why.

It shall be noted that there is no need to recompile everything, when a library's patched: you only need to relink the executables and rebuild the packages

Still, this requires a somewhat bigger infrastructure

> That's not a difference of security, only of download size (*).

It is a difference of security, because now when there's an issue with (e.g.) OpenSSL, instead of just the OpenSSL distro package team having to worry about it, the MySQL distro package team has to, the Postgres distro package team, Nginx, Apache, cURL, OpenSSH, etc.

All of those teams have to coordinate to release at the same time.

We're talking about distro packages, not upstream software releases.

> We're talking about distro packages, not upstream software releases.

Yes, by "the MySQL package team" I meant the MySQL distro package team. Edited to clarify.

But even if applied to the upstream team that releases from (e.g.) repo.mysql.org or repo.postgres.org it would apply: they're now worrying about all their dependencies as well their own code, instead of just specifying in the .deb or .rpm file "I need libssl3" and letting the OS take care of it.

It would become a huge duplication of effort to keep up on security updates.

At $JOB we have a general policy to always use the distro-supplied version of a package whenever possible, as if we compile it on our own and put it into /usr/local or /opt, we now have to babysit that code for security and such ourselves instead of 'outsourcing' it to the distro.

Ain't nobody got time for that.

Security + build time isn't the issue, but security + dev/testing time is.

Maintaining a secure package of zlib takes linearly more time with more versions of it used.

All distros are manpower limited.

There's only one version of zlib, the distro-packaged version, in the scenario of this discussion.

As I read it, that's 100% wrong: Isn't the discussion precisely about using the distro-packaged version vs. having other versions statically linked?

> A statically-linking distro would queue up those thousand packages to be rebuilt and you would receive them via OS update, just as you would with a dynamically-linking distro. The difference is just in whether you have to download 1000 updated packages or 1.

That is a large difference

But more significantly, you're assuming the only software installed is from the distro. This isn't what OP is talking about (unless the distro screwed up their package dependencies to get the not found error discussed.

Outside the distro-provided software, you either have to rebuild them all manually or wait for the proprietary software to do it and ship you a fix.

my /usr is 24G (restricting just to binary dirs, seems 18G). If every single time glibc had an update (perhaps a handful of times a year), I had to update my entire /usr (or with a bit more intelligence, just the binary packages), I'd be burning at least 100G (if not much more) of SSD life a year.

in a world of SSDs that wear out, the concept of updating the entire install every single time, seems problematic.

Have you ever actually worn out an SSD by compiling too much? I ran gentoo on SSDs for several years, never had an issue. If most compilation is happening in memory, updating software from source shouldn't be significantly more damaging to drives than binary patching?