A bug in the SmallVec::insert_many method caused it to allocate a buffer that was smaller than needed. It then wrote past the end of the buffer, causing a buffer overflow and memory corruption on the heap.

This bug was only triggered if the iterator passed to insert_many yielded more items than the lower bound returned from its size_hint method.

The flaw was corrected in smallvec 0.6.14 and 1.6.1, by ensuring that additional space is always reserved for each item inserted. The fix also simplified the implementation of insert_many to use less unsafe code, so it is easier to verify its correctness.

Thank you to Yechan Bae (@Qwaz) and the Rust group at Georgia Tech’s SSLab for finding and reporting this bug.

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);

OpenSSL has a modified bit that it can set on on X509_NAME objects. If this bit is set then the object is not thread-safe even when it appears the code is not modifying the value.

Thanks to David Benjamin (Google) for reporting this issue.

SubjectAlternativeName and ExtendedKeyUsage arguments were parsed using the OpenSSL function X509V3_EXT_nconf. This function parses all input using an OpenSSL mini-language which can perform arbitrary file reads.

Thanks to David Benjamin (Google) for reporting this issue.

These functions would crash when the context argument was None with certain extension types.

Thanks to David Benjamin (Google) for reporting this issue.

If an attacker is able to flood the network with pairs of HEADERS/RST_STREAM frames, such that the h2 application is not able to accept them faster than the bytes are received, the pending accept queue can grow in memory usage. Being able to do this consistently can result in excessive memory use, and eventually trigger Out Of Memory.

This flaw is corrected in hyperium/h2#668, which restricts remote reset stream count by default.