RUSTSEC-2020-0082

ordered_float:NotNan may contain NaN after panic in assignment operators

Reported

December 6, 2020

Issued

December 6, 2020 (last modified: June 13, 2023)

Package

ordered-float (crates.io)

Type

Vulnerability

Keywords

#unwind

Aliases

References

https://github.com/reem/rust-ordered-float/pull/71

CVSS Score

5.5 MEDIUM

CVSS Details

Attack vector: Local
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Patched

^1.1.1
>=2.0.1

Unaffected

<0.2.2

Description

After using an assignment operators such as NotNan::add_assign, NotNan::mul_assign, etc., it was possible for the resulting NotNan value to contain a NaN. This could cause undefined behavior in safe code, because the safe NotNan::cmp method contains internal unsafe code that assumes the value is never NaN. (It could also cause undefined behavior in third-party unsafe code that makes the same assumption, as well as logic errors in safe code.)

This was mitigated starting in version 0.4.0, by panicking if the assigned value is NaN. However, in affected versions from 0.4.0 onward, code that uses the NotNan value during unwinding, or that continues after catching the panic, could still observe the invalid value and trigger undefined behavior.

The flaw is fully corrected in versions 1.1.1 and 2.0.1, by ensuring that the assignment operators panic without modifying the operand, if the result would be NaN.

Advisory available under CC0-1.0 license.