Safe Parsers in Rust: Changing the World Step by Step

Parsers are critical parts of applications, exposed to potentially malicious data but also plagued by the same bugs over a period of years, like memory-related problems. Solutions exist but are often not adopted: many of them require rewriting entire software packages. We describe how to leverage Rust’s safety features and close integration with C, the strength of the nom [1] parser combinators library, along with a thorough methodology [2] to make existing software much more secure by rewriting critical parts. By surgically replacing functions, we intend to initiate a change towards robust and memory-safe parsers.