GHSA-3m6f-3gfg-4x56: Panic on incorrect date input to `simple_asn1`

Version 0.6.0 of the simple_asn1 crate panics on certain malformed inputs to its parsing functions, including from_der and der_decode. Because this crate is frequently used with inputs from the network, this should be considered a security vulnerability.

The issue occurs when parsing the old ASN.1 “UTCTime” time format. If an attacker provides a UTCTime where the first character is ASCII but the second character is above 0x7f, a string slice operation in the from_der_ function will try to slice into the middle of a UTF-8 character, and cause a panic.

This error was introduced in commit d7d39d709577710e9dc8, which updated simple_asn1 to use time instead of chrono because of RUSTSEC-2020-159. Versions of simple_asn1 before 0.6.0 are not affected by this issue.

The patch was applied in simple_asn1 version 0.6.1.