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.

On Windows, configuring a named pipe server with pipe_mode will force ServerOptions::reject_remote_clients as false.

This drops any intended explicit configuration for the reject_remote_clients that may have been set as true previously.

The default setting of reject_remote_clients is normally true meaning the default is also overridden as false.

Workarounds

Ensure that pipe_mode is set first after initializing a ServerOptions. For example:

let mut opts = ServerOptions::new();
opts.pipe_mode(PipeMode::Message);
opts.reject_remote_clients(true);

When a Some(...) value was passed to the properties argument of either of these functions, a use-after-free would result.

In practice this would nearly always result in OpenSSL treating the properties as an empty string (due to CString::drop's behavior).

The maintainers thank quitbug for reporting this vulnerability to us.