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Most build systems are turing-complete. Rust, at least, drastically reduces the need for custom build scripts (most of my projects have empty build.rs files or

Most build systems are turing-complete. Rust, at least, drastically reduces the need for custom build scripts (most of my projects have empty build.rs files or lack one entirely), and build.rs being in the same language as the rest of the codebase aids transparency immensely.

bonzini 3y ago
That doesn't make build.rs any less of a juicy target for a supply chain attack. Arbitrary code downloaded from the internet and run at build time? That's a nightmare scenario for auditing, much worse than anything Autotools or CMake can offer.
- timschmidt 3y ago
  You're not wrong about arbitrary code execution. It's just that your statement applies to most of the packages on any linux distribution, Autotools and Cmake included, regardless of language. Many moreso than Rust due to the aforementioned features of Cargo and build.rs not requiring me to be an expert in a second language just to audit it.
  - bonzini 3y ago
    Packages in a Linux distro are not built on my machine, they are built by the distro in a sandbox. Every time I type "cargo build" I am potentially running arbitrary code downloaded from the internet. Every time I type "make" in an Autotools program only my code runs. > not requiring me to be an expert in another language just to audit it. Do you do that every time your Cargo.lock changes?
    - timschmidt 3y ago
      > Every time I type "make" in an Autotools program only my code runs. Says who? Make is just as good at calling arbitrary code as Cargo. Including code that reaches out over the network. Have you audited every single makefile to ensure that isn't the case?
      - bonzini 3y ago
        I am talking about my makefiles. They don't automatically build dependencies that I have no control on. Whereas building my crate can run code locally that no one has ever audited.
        timschmidt 3y ago
        So... you're complaining about what could happen in a Rust build if you include a library without examining that library first? How do you think that is different from doing the same in any other language?
        bonzini 3y ago
        The difference is that in another language the build step is delegated to someone else who has packaged the code, and every version has presumably gone through some kind of audit. With Rust I have no idea what new transitive dependencies could be included any time I update one of my dependencies, and what code could be triggered just by building my program without even running it. Again, we're not talking about the dependencies that I choose, but the whole transitive closure of dependencies, including the most low-level. Did you examine serde the first time you used a dependency that used it? serde did have in the past a slightly sketchy case of using a pre-built binary. Or the whole dependency tree of Bevy? I mean, Rust has many advantages but the cargo supply chain story is an absolute disaster---not that it's alone, pypi or nodejs or Ruby gems are the same.
        timschmidt 3y ago
        > The difference is that in another language the build step is delegated to someone else who has packaged the code Fedora packages a large number of Rust libraries, just as you describe. Nothing prevents you from using the packaged libraries if you prefer them. You may find helpful information here: https://docs.fedoraproject.org/en-US/packaging-guidelines/Rust/ https://docs.fedoraproject.org/en-US/packaging-guidelines/Ru...
    - fragmede 3y ago
      seems trivial for a configure script to call curl/wget somewhere in the depths of it, no?
      - timschmidt 3y ago
        Exactly. And at least Cargo will refuse to download a crate which has been yanked. So any crate which has been discovered to be compromised can be yanked, preventing further damage even when someone has already downloaded something which depends on it. Building packages with up-to-date dependencies is also vastly preferable to building against ancient copies of libraries vendored into a codebase at some point in the past, a situation I see far too often in C/C++ codebases.
      - Hackbraten 3y ago
        Debian’s rules files often deliberately sinkhole the entire network during the build. It’s not the worst idea.
        fragmede 3y ago
        I wonder if you could do it inside the config script without the network.

bonzini 3y ago

That doesn't make build.rs any less of a juicy target for a supply chain attack. Arbitrary code downloaded from the internet and run at build time? That's a nightmare scenario for auditing, much worse than anything Autotools or CMake can offer.

timschmidt 3y ago
You're not wrong about arbitrary code execution. It's just that your statement applies to most of the packages on any linux distribution, Autotools and Cmake included, regardless of language. Many moreso than Rust due to the aforementioned features of Cargo and build.rs not requiring me to be an expert in a second language just to audit it.
- bonzini 3y ago
  Packages in a Linux distro are not built on my machine, they are built by the distro in a sandbox. Every time I type "cargo build" I am potentially running arbitrary code downloaded from the internet. Every time I type "make" in an Autotools program only my code runs. > not requiring me to be an expert in another language just to audit it. Do you do that every time your Cargo.lock changes?
  - timschmidt 3y ago
    > Every time I type "make" in an Autotools program only my code runs. Says who? Make is just as good at calling arbitrary code as Cargo. Including code that reaches out over the network. Have you audited every single makefile to ensure that isn't the case?
    - bonzini 3y ago
      I am talking about my makefiles. They don't automatically build dependencies that I have no control on. Whereas building my crate can run code locally that no one has ever audited.
      - timschmidt 3y ago
        So... you're complaining about what could happen in a Rust build if you include a library without examining that library first? How do you think that is different from doing the same in any other language?
        bonzini 3y ago
        The difference is that in another language the build step is delegated to someone else who has packaged the code, and every version has presumably gone through some kind of audit. With Rust I have no idea what new transitive dependencies could be included any time I update one of my dependencies, and what code could be triggered just by building my program without even running it. Again, we're not talking about the dependencies that I choose, but the whole transitive closure of dependencies, including the most low-level. Did you examine serde the first time you used a dependency that used it? serde did have in the past a slightly sketchy case of using a pre-built binary. Or the whole dependency tree of Bevy? I mean, Rust has many advantages but the cargo supply chain story is an absolute disaster---not that it's alone, pypi or nodejs or Ruby gems are the same.
        timschmidt 3y ago
        > The difference is that in another language the build step is delegated to someone else who has packaged the code Fedora packages a large number of Rust libraries, just as you describe. Nothing prevents you from using the packaged libraries if you prefer them. You may find helpful information here: https://docs.fedoraproject.org/en-US/packaging-guidelines/Rust/ https://docs.fedoraproject.org/en-US/packaging-guidelines/Ru...
  - fragmede 3y ago
    seems trivial for a configure script to call curl/wget somewhere in the depths of it, no?
    - timschmidt 3y ago
      Exactly. And at least Cargo will refuse to download a crate which has been yanked. So any crate which has been discovered to be compromised can be yanked, preventing further damage even when someone has already downloaded something which depends on it. Building packages with up-to-date dependencies is also vastly preferable to building against ancient copies of libraries vendored into a codebase at some point in the past, a situation I see far too often in C/C++ codebases.
    - Hackbraten 3y ago
      Debian’s rules files often deliberately sinkhole the entire network during the build. It’s not the worst idea.
      - fragmede 3y ago
        I wonder if you could do it inside the config script without the network.