s c h e m a t i c s : c o o k b o o k

This Web

Other Webs

Schematics

RSS

Scheme Links

Evaluating untrusted code

Problem

We want to evaluate code outside our control (e.g., deserializing s-expressions in data files).

Solution

Restrict the evaluated code so it has no file or network access:

(define (safe-eval sxp)
  (parameterize ([current-security-guard
                  (make-security-guard (current-security-guard)
                                       (lambda (procname path access)
                                         (error procname
                                                "No file access"))
                                       (lambda (procname host port conn)
                                         (error procname
                                               "No network access")))])
    (eval sxp)))

Discussion

This is a nice recipe. Are these security guards v300 specific? There is more to say in this recipe: one can prevent 'dangerous' functions from being executed by evaluating the code in a namespace that doesn't include the functions in question. -- NoelWelsh - 09 Dec 2004

Moved this recipe to DynamicChapter. Please help move other related recipes out of IdiomChapter and into DynamicChapter. -- NoelWelsh - 15 Apr 2005

Comments about this recipe

Contributors

-- DanielSilva - 09 Dec 2004