[Secure-testing-team] Bug#566002: CVE-2010-0001: integer underflow

[Steffen Joeris]

Package: gzip
Version: 1.3.12-8
Severity: grave
Tags: security patch

Hi Bdale, Carl

Carl, I saw too late that you're a new co-maintainer so I only
forwarded the pre-notification to Bdale (who is probably busy at LCA).
i
the following CVE (Common Vulnerabilities & Exposures) id was
published for gzip and is still open for unstable/testing.

CVE-2010-0001[0] (from the DSA text):
Aki Helin discovered an integer underflow when decompressing files that
are compressed using the LZW algorithm. This could lead to the execution
of arbitrary code when trying to decompress a crafted LZW compressed
gzip archive.

If you fix the vulnerability please also make sure to include the
CVE id in your changelog entry.

I am available for NMU/sponsoring, in case you're still busy, just drop
me a line, please.

Cheers
Steffen

For further information see:

[0] http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2010-0001
    http://security-tracker.debian.org/tracker/CVE-2010-0001

patch:
--- gzip-1.3.12.orig/unlzw.c
+++ gzip-1.3.12/unlzw.c
@@ -248,7 +248,8 @@
        int  o;

     resetbuf:
-       e = insize-(o = (posbits>>3));
+       o = posbits >> 3;
+       e = o <= insize ? insize - o : 0;

        for (i = 0 ; i < e ; ++i) {
            inbuf[i] = inbuf[i+o];