there comes a point where we can't let dependencies on Amiga or DEC Alpha (companies/platforms that haven't existed in literal decades) hold the rest of us back. If someone wants to port rust/llvm to those platforms more power to them, but the rest of us don't need to suffer. The only platform that actually matters that was negatively effected by that change is musl/alpine because there aren't musl wheels available and you have to build the rust part from source.
What about embedded platforms, which tend to remain relevant (i.e. present in large numbers out in the real world) much longer than desktop or server platforms? Don't they matter? Don't they need updates, including for security, as much as any other?
As a security library... you really ought to be updating it every half year of so.
This has nothing to do with rust though. Rust maintains full backwards compatibility, so even if you upgrade the compiler (which is unlikely on long lived platforms) and not the library nothing breaks.
Nor is it necessarily the case that upgrading the library will require updating rust (though this isn't what you appear to be complaining about). Not only is it a build time dependency (that you don't even need to install if you are on common platforms which ave prebuilt binaries), but they are explicitly testing against a particular fixed old version of rust as well as recent ones: https://github.com/pyca/cryptography/blob/main/.github/workf...
> I'd say such an initiative needs a long-term supported version of rust, similar to C99 or so.
This describes every version of rust since 1.0. Rust is fully backwards compatible, unlike new C standards.
> Do we have anyone committed to providing a stable rust environment for these cases?
Yes, the entire rust team...
> Especially considering that rust has no ABI for dynamic libraries.
This is... rather irrelevant? Technically it does have support for the C abi for dynamic libraries though.
The fact that rustc is backwards compatible is great, sure. But it does not solve the problem of distributors.
Say you have libfoo-1.0 that uses rust and cargo 1.2 . A distributor that now releases their linux version and wants to ship libfoo-1.0 must consider the requirements for supporting it. This support usually outlives the upstream support.
If libfoo-1.0 uses C, for instance, it is highly likely that a distributor can backport any security-relevant changes from libfoo-1.1, 1.2, and later into 1.0.
In the case of rust there are two uncertainties creeping in: One is the highly dynamic nature of cargo dependencies. libfoo might depend on a myriad of crates transitively and rust simply is too young to provide any experience in how long they will be available or supported. And no, it is generally not a good idea to update to new feature releases for security updates. This is something that stable distributions explicitly try to avoid.
So our distributor now must consider if changes in libfoo-1.2 pulled in changes via cargo that cannot be easily backported because they are feature releases or have a dependency on a newer version of rust.
The second problem is the compiler itself. Any change in libfoo-1.2 might require a newer version of rust. It is great that they want to be backwards compatible but now our distributor must consider upgrading a substantial piece of software during the support period (and testing the backwards compatibility, of course) just to backport a security fix.
Please don't get me wrong, I really like rust and I think these problems can be solved. But I also like stable software and all these languages with their package repositories seem to simply ignore everything that's older than one or two years. If rust wants to become a new C, which I would very much like, it needs to demonstrate a certain stability.
> One is the highly dynamic nature of cargo dependencies. libfoo might depend on a myriad of crates transitively and rust simply is too young to provide any experience in how long they will be available or supported. And no, it is generally not a good idea to update to new feature releases for security updates. This is something that stable distributions explicitly try to avoid.
crates.io is designed so that dependencies put up on it remain available forever, and that the only other cargo related dependencies also have to be hosted on crates.io - solving the availability problem.
Of course if you're trying to backport a security fix to an old version of a transitive dependency that (like the non-transitive dependency) is no longer supported, you do have to make that backport. Once you make that backport it's easy to update the version of the transitive dependency with a [patch] section in the top level Cargo.toml.
> The second problem is the compiler itself. Any change in libfoo-1.2 might require a newer version of rust.
This is already mitigated in multiple ways. As discussed before, people do make sure to support old versions of compilers, you don't need to have a compiler on your target platform anyways. But moreover, the amount new language features make backporting difficult is dwarfed by the amount that internal library changes do.
While in C/C++ I can just build a fork as dynamic library and put it to the system image or to the own package manager repo.
I mean for sure Cargo is great for small hobby projects, but for the big complicated enterprise projects it's not really suitable. Even Google doesn't use Cargo in Fuchsia and vendors everything.
If you're making a small change, you use a [patch] section in the Cargo.toml for your workspace if you're using one, or the Cargo.toml for your binary/.so/.a if you're not, and it will cause your entire dependency tree to use your forked library. You don't need to fork the entire ecosystem as you suggest.
The [patch] works at the "workspace" level (and you generally should stick your entire complex system under one workspace), so if you use that feature properly for your "complex system" (keeping everything under one workspace), it is a one line change to replace the dependency for your entire system. If you use multiple, well, one per workspace that produces a binary/.so/.a.
Also, for big enterprise projects, I would assume you would use a private registry in the first place, which is apparently well supported (though I haven't used it). That's how the enterprise places I work at have dealt with python dependencies for instance (I haven't used rust in a enterprise).
I can sort of understand people trying to maintain LTS linux distros complaining that for their purposes this is a bit of a pain compared to C style shared libraries (because they need to modify a lot of rust workspaces)... but to be honest I think that's a question of their package management tooling not rust's. Rust provided the tools they need to make their custom tooling work. As a user the number of times shared libraries have caused me pain makes me think that this static linking is the superior method of packaging.
Also although we are talking about open source here, in many OSes, and enterprises, distribution of binary libraries is a very important subject, which cargo doesn't allow for.
In theory perhaps. But in theory this could happen with C or C++ too. In practice, security patches try to be minimal.
Sure, if you're several versions behind you might have more work to do. But you knew you were gonna own that problem when you decided to lag behind.
I could have got around it, but it took me by surprise that a Python dep required it. Not being negative or criticising the fact, just first time I had observed it.
Progress should not be held back for the rest of us because a few will get left behind. If you are running something so old that LLVM doesn't support it, upgrade. It's 2021.
There is a python library that recently switched to rust (partially) and now cannot be build on several platforms.
This also means that very long-lived platforms will probably be forced to upgrade that library every half year or so in line with the development of rust.
I'd say such an initiative needs a long-term supported version of rust, similar to C99 or so.
And this does not even account for cargo. I know you don't have to use cargo, but is that practical?
How are we going to maintain stable software for, say, ten years or more? Do we have anyone committed to providing a stable rust environment for these cases? Especially considering that rust has no ABI for dynamic libraries.
Oh and by the way: We need a way to bootstrap rust as well. The current distribution downloads binaries of the last one to build itself. And it ships with a vendored version of llvm.
So in conclusion: I really like the rust language. But I am concerned that it is still way too immature and to "hip" for long-running, stable projects.