[cmucl-ticket] [cmucl] #67: deftransform for replace is unsafe

[cmucl]

#67: deftransform for replace is unsafe
--------------------+-------------------------------------------------------
 Reporter:  rtoy    |       Owner:  somebody
     Type:  defect  |      Status:  new     
 Priority:  major   |   Milestone:          
Component:  Core    |     Version:  2012-12 
 Keywords:          |  
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 Consider this function
 {{{
 (defun bad (s)
   (declare (simple-string s))
   (replace s s :start2 100 :end2 105))
 }}}
 After compiling this,
 {{{
 (bad (copy-seq "1234567890"))
 }}}
 Produces a totally bogus result, filling in the first 4 characters of the
 resulting string with garbage.

 The problem is that the deftransform for replace just calls {{{BIT-BASH-
 COPY}}} without verifying that the start and end indices make sense for
 the given string.  Note that it also doesn't check to see that end >=
 start, but this gets handled by {{{BIT-BASH-COPY}}} which gets a negative
 length and signals an error.

-- 
Ticket URL: <http://trac.common-lisp.net/cmucl/ticket/67>
cmucl <http://common-lisp.net/project/cmucl>
Cmucl is a high-performance, free Common Lisp implementation.