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> If memory safety was "just the right regulations" easy, it would have already been solved. Memory safety is already a solved problem in regulated industries.

by lmm 2y ago

> If memory safety was "just the right regulations" easy, it would have already been solved. Memory safety is already a solved problem in regulated industries. It's not a hard problem as such. People just don't want to solve it and don't have any incentive to: companies aren't penalised for writing buggy software, and individual engineers are if anything rewarded for it. > Every competent developer loves getting things right. Unfortunately a lot of developers care more about being able to claim mastery of something hard. No-one gets cred for just writing the thing in Java and not worrying about memory issues, even though that's been a better technical choice for decades for the overwhelming majority of cases.

wakawaka28 2y ago
Regulated industries have overwhelmingly boring and expensive software compared to others. They do things like banning recursion and dynamic arrays lol. Memory safety in every aspect possible just isn't worth it for most applications. And the degree of memory safety that is worth it is a lot less than Rust developers seem to think, and the degree of memory safety granted by Rust is less than they think as well.
- lmm 2y ago
  Memory safety isn't worth it as long as leaking all your users' data (and granting attackers control over their systems) doesn't cost much. As attacks get more sophisticated and software gets more important, the costs of memory unsafety go up.
  - wakawaka28 2y ago
    What you've said is true but I still think the problem is overblown, and solutions at the hardware level are disregarded in favor of dubious and more costly software rewrite solutions. If something like CHERI was common then it would automatically find most security-related memory usage bugs, and thus lead to existing software getting fixed for all hardware.
    - lmm 2y ago
      IME you can't reliably extract the intent from the C code, much less the binary, so you can't really fix these bugs without a human rewriting the source. The likes of CHERI might make exploitation harder, but it seems to me that ROP-style workarounds will always be possible, because fundamentally if the program is doing things that look like what it was meant to do then the hardware can never distinguish whether it's actually doing what it was meant to do or not. Even if you were able to come up with a system that ensured that standards-compliant C programs did not have memory bugs (which is already unlikely), that would still require a software rewrite approach in practice because all nontrivial C programs/libraries have latent undefined behaviour.
      - wakawaka28 2y ago
        There may be some cases where code would need to be adjusted or annotated to use CHERI well, but that has to be easier than translating to or interfacing with another language.
      - gw2 2y ago
        > IME you can't reliably extract the intent from the C code, much less the binary, so you can't really fix these bugs without a human rewriting the source. I am pretty sure that the parent is talking about hardware memory safety which doesn't require any "human rewriting the source".
        lmm 2y ago
        > I am pretty sure that the parent is talking about hardware memory safety which doesn't require any "human rewriting the source". It does though. The hardware might catch an error (or an "error") and halt the program, but you still need a human to fix it.
        kazinator 2y ago
        The human might say, sorry my C program is not compatible with your hardware memory safety device. I won't/can't fix that.
lelanthran 2y ago
> Memory safety is already a solved problem in regulated industries. It's not a hard problem as such. It's not hard, no, but it is expensive, because those regulations have a battery of tests run by a thirdy party that you will pay money to each time you want to recertify. I've worked in two regulated industries; the recertification is the expensive part, not the memory errors.
Nevermark 2y ago
> Memory safety is already a solved problem Most famously in Rust. Even there it takes work. The problem is a practical coding work efficiency (and quality) one. You are right that there are no intractable memory problems even in the unsafest least helpful languages.

by lmm 2y ago

wakawaka28 2y ago

Regulated industries have overwhelmingly boring and expensive software compared to others. They do things like banning recursion and dynamic arrays lol. Memory safety in every aspect possible just isn't worth it for most applications. And the degree of memory safety that is worth it is a lot less than Rust developers seem to think, and the degree of memory safety granted by Rust is less than they think as well.

lmm 2y ago
Memory safety isn't worth it as long as leaking all your users' data (and granting attackers control over their systems) doesn't cost much. As attacks get more sophisticated and software gets more important, the costs of memory unsafety go up.
- wakawaka28 2y ago
  What you've said is true but I still think the problem is overblown, and solutions at the hardware level are disregarded in favor of dubious and more costly software rewrite solutions. If something like CHERI was common then it would automatically find most security-related memory usage bugs, and thus lead to existing software getting fixed for all hardware.
  - lmm 2y ago
    IME you can't reliably extract the intent from the C code, much less the binary, so you can't really fix these bugs without a human rewriting the source. The likes of CHERI might make exploitation harder, but it seems to me that ROP-style workarounds will always be possible, because fundamentally if the program is doing things that look like what it was meant to do then the hardware can never distinguish whether it's actually doing what it was meant to do or not. Even if you were able to come up with a system that ensured that standards-compliant C programs did not have memory bugs (which is already unlikely), that would still require a software rewrite approach in practice because all nontrivial C programs/libraries have latent undefined behaviour.
    - wakawaka28 2y ago
      There may be some cases where code would need to be adjusted or annotated to use CHERI well, but that has to be easier than translating to or interfacing with another language.
    - gw2 2y ago
      > IME you can't reliably extract the intent from the C code, much less the binary, so you can't really fix these bugs without a human rewriting the source. I am pretty sure that the parent is talking about hardware memory safety which doesn't require any "human rewriting the source".
      - lmm 2y ago
        > I am pretty sure that the parent is talking about hardware memory safety which doesn't require any "human rewriting the source". It does though. The hardware might catch an error (or an "error") and halt the program, but you still need a human to fix it.
        kazinator 2y ago
        The human might say, sorry my C program is not compatible with your hardware memory safety device. I won't/can't fix that.

lelanthran 2y ago

> Memory safety is already a solved problem in regulated industries. It's not a hard problem as such. It's not hard, no, but it is expensive, because those regulations have a battery of tests run by a thirdy party that you will pay money to each time you want to recertify. I've worked in two regulated industries; the recertification is the expensive part, not the memory errors.

Nevermark 2y ago

> Memory safety is already a solved problem Most famously in Rust. Even there it takes work. The problem is a practical coding work efficiency (and quality) one. You are right that there are no intractable memory problems even in the unsafest least helpful languages.