Re: [Chicken-janitors] #1216: string-ref specialization elides range check

[Chicken Trac]

#1216: string-ref specialization elides range check
--------------------------+---------------------
  Reporter:  syn          |      Owner:
      Type:  defect       |     Status:  new
  Priority:  critical     |  Milestone:  someday
 Component:  scrutinizer  |    Version:  4.10.x
Resolution:               |   Keywords:
--------------------------+---------------------
Changes (by sjamaan):

 * priority:  major => critical


Comment:

 Changing it to {{{C_i_string_ref}}} would still be beneficial due to
 inlining.  Note that there are also two rewrites in {{{c-platform.scm}}};
 an unsafe one that uses {{{C_subchar}}} and a safe one that uses
 {{{C_i_string_ref}}}.

 I think the real problem here is that there are two kinds of unsafe: the
 kind that doesn't check its argument types (which will result in crashes
 when passed the wrong type; but in the scrutinizer that means it wouldn't
 be unsafe because the types are checked elsewhere) and the kind that
 doesn't check anything. The latter results in unsafe specializations which
 indeed may result in security nightmares.

 I'm raising this ticket to "critical" because there may be some true
 landmines waiting to go off in Scheme code that's otherwise safe.
 Rewrites like this change the semantics of the code in such a way that you
 can't reason about its safety anymore.

--
Ticket URL: <http://bugs.call-cc.org/ticket/1216#comment:2>
CHICKEN Scheme <http://www.call-cc.org/>
CHICKEN Scheme is a compiler for the Scheme programming language.