CVE-2015-1463: clamav: special crafted petite can lead to a crash

[Sebastian Andrzej Siewior <cve-announce () ml breakpoint cc>]

I haven't requested this CVE but it looks to what I / AFL have
discovered.
petite [0] is too for compressing .exe (.dll and such) files under
windows. clamav [1] is a virus scanning tool which is able to unpack
such files during scanning.

A handcrafted file could lead the de-compressor to access beyond bounds
leading to crash because the compiler might have removed the boundary
check. The boundary remains there up to the gcc 4.7 series. Starting
with gcc 4.8 the compiler removes the check because it assumes that a
signed overflow can not become negative. According to the gcc folks this
assumption is within the C specification. As a fix [2] one of the
variables becomes unsigned and is part of the current (0.96.6) release.

This bug has been discovered by AFL [3], american fuzzy lop.

[0] http://www.un4seen.com/petite/
[1] http://www.clamav.net/
[2] https://github.com/vrtadmin/clamav-devel/commit/96ff19a19eba64bdf47f2f12ecdbc5ee331c09e2
[3] http://lcamtuf.coredump.cx/afl/

Sebastian