HistoryEdit

RUSTSEC-2020-0082

ordered_float:NotNan may contain NaN after panic in assignment operators

Issued
Package
ordered-float (crates.io)
Type
Vulnerability
Keywords
#unwind
Aliases
Details
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
Keywords
#unwind

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.