Wipe buffer strings that might contain plaintext.

diff --git a/v7/src/runtime/blowfish.scm b/v7/src/runtime/blowfish.scm
index cb2eabe92b016c2d2a7c650e73179598c1b77bb3..0e1fc4be8ab5431e304d58cf728401bbad4eb0f1 100644 (file)
--- a/v7/src/runtime/blowfish.scm
+++ b/v7/src/runtime/blowfish.scm
@@ -1,6 +1,6 @@
 #| -*-Scheme-*-
 
-$Id: blowfish.scm,v 1.12 1999/08/09 18:27:38 cph Exp $
+$Id: blowfish.scm,v 1.13 1999/08/10 16:59:46 cph Exp $
 
 Copyright (c) 1997, 1999 Massachusetts Institute of Technology
 
@@ -93,14 +93,21 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   (let ((key (blowfish-set-key key))
        (input-buffer (make-string 4096))
        (output-buffer (make-string 4096)))
-    (let loop ((m 0))
-      (let ((n (input-port/read-string! input input-buffer)))
-       (if (not (fix:= 0 n))
-           (let ((m
-                  (blowfish-cfb64 input-buffer 0 n output-buffer 0
-                                  key init-vector m encrypt?)))
-             (write-substring output-buffer 0 n output)
-             (loop m)))))))
+    (dynamic-wind
+     (lambda ()
+       unspecific)
+     (lambda ()
+       (let loop ((m 0))
+        (let ((n (input-port/read-string! input input-buffer)))
+          (if (not (fix:= 0 n))
+              (let ((m
+                     (blowfish-cfb64 input-buffer 0 n output-buffer 0
+                                     key init-vector m encrypt?)))
+                (write-substring output-buffer 0 n output)
+                (loop m))))))
+     (lambda ()
+       (string-fill! input-buffer #\NUL)
+       (string-fill! output-buffer #\NUL)))))
 
 (define (write-blowfish-file-header port)
   (write-string blowfish-file-header-v2 port)
@@ -143,13 +150,18 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
     (lambda (port)
       (let ((buffer (make-string 4096))
            (context (md5-init)))
-       (let loop ()
-         (let ((n (read-string! buffer 0 4096 port)))
-           (if (fix:= 0 n)
-               (md5-final context)
-               (begin
-                 (md5-update context buffer 0 n)
-                 (loop)))))))))
+       (dynamic-wind (lambda ()
+                       unspecific)
+                     (lambda ()
+                       (let loop ()
+                         (let ((n (read-string! buffer 0 4096 port)))
+                           (if (fix:= 0 n)
+                               (md5-final context)
+                               (begin
+                                 (md5-update context buffer 0 n)
+                                 (loop))))))
+                     (lambda ()
+                       (string-fill! buffer #\NUL)))))))
 
 (define (md5-sum->number sum)
   (let ((l (string-length sum)))