Re: [Caml-list] Cryptokit.Zlib uncompressing fails to terminate (fwd) (Patch)

[malc <malc@pulsesoft.com>]

On Sun, 17 Oct 2004, malc wrote:

> Hello,
>
> I have been unable to contact Xavier Leroy directly, so im reposting this
> message here. Few more words about the stream that takes uncompress into
> an endless loop, it is %100 valid zlib compressed data with 2 additional
> (gzip's crc and length) words at the end.
>
> ---------- Forwarded message ----------
> <snip>
> Hello Xavier,
>
>
>
> I noticed that uncompressing partially valid stream with
> Cryptokit.Zlib.uncompress() fails to terminate.
> http://www.boblycat.org/~malc/fail.tgz (489 bytes)
> Contains minimal testcase (Makefile + OCaml source)
>
> I would apreciate any info on the subject.

Following "fixes" it.

diff -ur /mnt/big/npf/incoming/caml/cryptokit-1.2/cryptokit.ml
/mnt/big/npf/bld/cryptokit-1.2/cryptokit.ml
--- /mnt/big/npf/incoming/caml/cryptokit-1.2/cryptokit.ml	Thu Jul 10
17:37:38 2003
+++ /mnt/big/npf/bld/cryptokit-1.2/cryptokit.ml	Tue Nov  2 19:18:41 2004
@@ -33,6 +33,7 @@
   | No_entropy_source
   | Entropy_source_closed
   | Compression_not_supported
+  | Input_buffer_to_big

 exception Error of error

@@ -2029,12 +2030,13 @@
     method put_substring src ofs len =
       if len > 0 then begin
         self#ensure_capacity 64;
-        let (_, used_in, used_out) =
+        let (finished, used_in, used_out) =
           inflate zs
                   src ofs len
                   obuf oend (String.length obuf - oend)
                   Z_SYNC_FLUSH in
         oend <- oend + used_out;
+        if finished then raise (Error Input_buffer_to_big);
         if used_in < len
         then self#put_substring src (ofs + used_in) (len - used_in)
       end
diff -ur /mnt/big/npf/incoming/caml/cryptokit-1.2/cryptokit.mli
/mnt/big/npf/bld/cryptokit-1.2/cryptokit.mli
--- /mnt/big/npf/incoming/caml/cryptokit-1.2/cryptokit.mli	Thu Jul 10
17:37:38 2003
+++ /mnt/big/npf/bld/cryptokit-1.2/cryptokit.mli	Tue Nov  2
19:17:42 2004
@@ -922,6 +922,9 @@
       (** End of file on a device or EGD entropy source. *)
   | Compression_not_supported
       (** The data compression functions are not available. *)
+  | Input_buffer_to_big
+      (** More data has been passed to a function than it can
+          gracefully hanlde *)

 exception Error of error
   (** Exception raised by functions in this library

-- 
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