Date: Fri, 18 Dec 2009 14:25:36 -0500 (EST) From: Josh Bressers <bressers@...hat.com> To: oss-security@...ts.openwall.com Cc: coley <coley@...re.org> Subject: Re: possible vulnerability in ghostscript >= 8.64 Use CVE-2009-4270 for the stack overflow. Thanks. ----- "Vincent Danen" <vdanen@...hat.com> wrote: > We had reported to us a crash in ghostscript's gdevcups.c, and I > don't > think it can be used to do anything more than crash ghostscript, > certainly not in our configurations (compiled with FORTIFY_SOURCE). > > Debug logging was added to gdevcups.c prior to the 8.64 release on > Oct > 17th, 2008: > > http://svn.ghostscript.com/viewvc?view=rev&revision=9165 > > The addition of the debug logging allowed for a MediaType string to > be > printed, which if longer than the 1024-byte buffer in errprintf would > cause ghostscript to crash This is due to errprintf() and > outprintf() > using vsprintf() on a fixed-length array on the stack. > > This issue does not affect versions of ghostscript older than 8.64; > for > 8.64 and newer, if compiled using FORTIFY_SOURCE (as it is in > Fedora), > this is turned into nothing more than a crash. On a system without > FORTIFY_SOURCE, this _might_ be exploitable, but I cannot say for > certain. > > As well, we can't see (in ghostscript 8.15 at least), any other calls > to > errprintf() or outprintf() that use the %s specifier with > user-supplied > strings (so arguably the vsprintf() calls in those functions should > be > fixed, but we don't see an immediate need to do so). > > I imagine that most vendors using ghostscript 8.64 or newer also have > a > newer glibc and are using FORTIFY_SOURCE protection, but I can't know > that for certain, so this is a general notice that the issue exists. > > Our bug report: > > https://bugzilla.redhat.com/show_bug.cgi?id=540760 > > this had also been reported previously upstream as well: > > http://bugs.ghostscript.com/show_bug.cgi?id=690829 > > -- > Vincent Danen / Red Hat Security Response Team -- JB
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