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Git security vulnerabilities announced

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Re: Git security vulnerabilities announced

#4

Post by xxpor »

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.

>It's unclear to me why our languages still default to modulo arithmetic semantics.

Because that's what processors do? (leaving aside backwards compatibility issues)

Re: Git security vulnerabilities announced

#5

Post by shepmaster »

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 had a chance to fix this, but also dropped the ball.

By default, a Rust project will panic on integer overflow in debug builds and will overflow on release builds. Two key points to note, however:

1. You can change the setting so that your project panics in release or overflows in debug mode.

2. We reserved the right to change the default at some point in the future. This will probably be widely communicated before it ever happens, and last I heard we are still waiting for the cost of performing those checks to be "reasonable" before thinking about making such a change.

Re: Git security vulnerabilities announced

#6

Post by sshine »

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, e.g.

  let (zero, _did_overflow) = u64::MAX.overflowing_add(1);

Re: Git security vulnerabilities announced

#9

Post by b112 »

sshine wrote: post #7

[Edit: According to @rlpb's comment, git 2.39.1 is already available on Ubuntu] To install the latest git on Ubuntu: sudo apt upgrade git [Former post included instructions on how to install git from https://launchpad.net/~git-core/+archive/ubuntu/ppa ]

Ubuntu will update git, without having to add this.

Re: Git security vulnerabilities announced

#10

Post by howinteresting »

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,…

You'll get a compile error when rustc can statically prove that it'll overflow (as in your example above). That is generally not possible.

The correct answer is what shepmaster said in a sibling comment.

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