Ecosyste.ms: Advisories

Security Advisories: GSA_kwCzR0hTQS1xdmM0LTc4Z3ctcHY4cM4AAy8O

Adverserial use of `make_bitflags!` macro can cause undefined behavior

The macro relied on an expression of the form Enum::Variant always being a
variant of the enum. However, it may also be an associated integer constant, in
which case there's no guarantee that the value of said constant consists only of
bits valid for this bitflag type.

Thus, code like this could create an invalid BitFlags<Test>, which would cause
iterating over it to trigger undefined behavior. As the debug formatter
internally iterates over the value, it is also affected.

use enumflags2::{bitflags, make_bitflags};

#[bitflags]
#[repr(u8)]
#[derive(Copy, Clone, Debug)]
enum Test {
    A = 1,
    B = 2,
}

impl Test {
    const C: u8 = 69;
}

fn main() {
    let x = make_bitflags!(Test::{C});
    // printing or iterating over x is UB
}

Permalink: https://github.com/advisories/GHSA-qvc4-78gw-pv8p
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS1xdmM0LTc4Z3ctcHY4cM4AAy8O
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Moderate
Classification: General
Published: over 1 year ago
Updated: over 1 year ago

Identifiers: GHSA-qvc4-78gw-pv8p
References:

• https://github.com/meithecatte/enumflags2/releases/tag/v0.7.7
• https://rustsec.org/advisories/RUSTSEC-2023-0035.html
• https://github.com/advisories/GHSA-qvc4-78gw-pv8p

Repository: https://github.com/meithecatte/enumflags2
Blast Radius: 0.0

Affected Packages