libssh2 developers report:
- Defend against possible integer overflows in comp_method_zlib_decomp.
- Defend against writing beyond the end of the payload in _libssh2_transport_read().
- Sanitize padding_length - _libssh2_transport_read().
- This prevents an underflow resulting in a potential out-of-bounds read if a server sends a too-large padding_length, possibly with malicious intent.
- Prevent zero-byte allocation in sftp_packet_read() which could lead to an out-of-bounds read.
- Check the length of data passed to sftp_packet_add() to prevent out-of-bounds reads.
- Add a required_size parameter to sftp_packet_require et. al. to require callers of these functions to handle packets that are too short.
- Additional length checks to prevent out-of-bounds reads and writes in _libssh2_packet_add().