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Git security vulnerabilities announced

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Re: Git security vulnerabilities announced

#11

Post by deathanatos »

sshine wrote: post #6
bbojan wrote: post #3

Both critical bugs are integer overflows. It's unclear to me why our languages still default to modulo arithmetic semantics. I feel Rust had a chance to fix this, but also dropped the ball.

Rust does have a fix for this: error: this arithmetic operation will overflow --> src/main.rs:2:18 | 2 | let a: u64 = u64::MAX + 1; | ^^^^^^^^^^^^ attempt to compute `u64::MAX + 1_u64`, which would overflow | = note: `#[deny(arithmetic_overflow)]` on by default Rust also allows for overflowing arithmetic (preserving the default to fail): https://doc.rust-lang.org/std/?search=overflowing It's generally less ergonomic,…

Edit: Gah, I'm a bit wrong too. There's the compiler error (this), and the runtime error (what I'm talking about below.)

Here's a link to the runtime variant: https://play.rust-lang.org/?version=stable&mode=debug&editio...

As a sibling notes, currently, this is for debug builds. So, if you change that playground to "Release", you'll see it wrap.

(I love this feature, and I wish they had done it in release mode too. The sibling comment has some notes on that, too.)

(But, e.g., were `git` written in Rust, presumably the end product would be a release build. Now, you can enable the check there, but that is something you have to do, today.)

(But also note, that, in all cases, it's well-defined. Vs. C, where some overflows are UB.)

Re: Git security vulnerabilities announced

#13

Post by bouke »

What is git doing with the system’s spell checker? This is the first time I’ve read about git using a spell checker. I know that various gui clients do spell checking, but I’m not aware of git itself doing anything related to this.

Re: Git security vulnerabilities announced

#14

Post by hypeatei »

sshine wrote: post #6
bbojan wrote: post #3

Both critical bugs are integer overflows. It's unclear to me why our languages still default to modulo arithmetic semantics. I feel Rust had a chance to fix this, but also dropped the ball.

Rust does have a fix for this: error: this arithmetic operation will overflow --> src/main.rs:2:18 | 2 | let a: u64 = u64::MAX + 1; | ^^^^^^^^^^^^ attempt to compute `u64::MAX + 1_u64`, which would overflow | = note: `#[deny(arithmetic_overflow)]` on by default Rust also allows for overflowing arithmetic (preserving the default to fail): https://doc.rust-lang.org/std/?search=overflowing It's generally less ergonomic,…

Slightly related, I wonder why the return type for `overflowing_add` isn't `Result` and instead a tuple containing a boolean?

Re: Git security vulnerabilities announced

#15

Post by throwanem »

nequo wrote: post #12
tinus_hn wrote: post #8

Sounds terrible, however typically you’re checking out code you’re going to compile and run anyway.

That is a little less than typical for me. I sometimes check out code to read it or to decide if I should compile and run it.

Likewise; editor tooling is better than Github's. In general, I feel like "git checkout" alone being a potentially unsafe action breaks a lot of people's mental threat models.

Re: Git security vulnerabilities announced

#16

Post by j1elo »

nequo wrote: post #12
tinus_hn wrote: post #8

Sounds terrible, however typically you’re checking out code you’re going to compile and run anyway.

That is a little less than typical for me. I sometimes check out code to read it or to decide if I should compile and run it.

You might find git-peek useful:

https://github.com/jarred-sumner/git-peek

Re: Git security vulnerabilities announced

#17

Post by kgeist »

bbojan wrote: post #3

Both critical bugs are integer overflows. It's unclear to me why our languages still default to modulo arithmetic semantics. I feel Rust had a chance to fix this, but also dropped the ball.

I'm quite paranoid about integer overflows, so in my hobby projects I now have a habit of always using helper functions (which generate an error on overflow) instead of "bare" math operators, and whenever I see a bare math operator without any checks in an open source project (and from what I've seen almost no one checks for overflows) I wonder whether they thought about potential consequences or I'm being too paranoid

Re: Git security vulnerabilities announced

#19

Post by jcranmer »

bbojan wrote: post #3

Both critical bugs are integer overflows. It's unclear to me why our languages still default to modulo arithmetic semantics. I feel Rust had a chance to fix this, but also dropped the ball.

Rust makes integer overflow panic in debug builds, so Rust code is effectively required to opt into overflowing operations for correctness reasons. It disables those checks on release builds for performance reasons, but as sibling comments point out, it reserves the right to change that behavior.

Unfortunately, there is a circular dependency here. Languages are reluctant to make integer overflows error conditions because there is a moderately high overhead to checking overflow conditions constantly, and processors (and compilers) are unwilling to make overflow checks cheaper because they benchmarks they care about don't do such checks.

Re: Git security vulnerabilities announced

#20

Post by Arnavion »

bouke wrote: post #13

What is git doing with the system’s spell checker? This is the first time I’ve read about git using a spell checker. I know that various gui clients do spell checking, but I’m not aware of git itself doing anything related to this.

As the article states, it's a feature of git-gui, not the git CLI.

The vulnerability is Windows-only, so maybe whatever Windows users do to install git always gives them git-gui. But at least for Linux, the distro might package it separately (mine does), so you won't even have it if you didn't install it.

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