Date: Thu, 31 Dec 2015 03:16:33 +0000 From: Ben Hutchings <ben@...adent.org.uk> To: cve-assign@...re.org, kseifried@...hat.com Cc: oss-security@...ts.openwall.com Subject: Re: mail-client/claws-mail-3.13.1: Stack Overflow - CVE needed? On Mon, 2015-12-21 at 21:31 -0500, cve-assign@...re.org wrote: > > https://bugs.gentoo.org/show_bug.cgi?id=569010 > > > http://www.thewildbeast.co.uk/claws-mail/bugzilla/show_bug.cgi?id=3557 > > > > So in codeconv.c there is a function for japanese character set > > > conversion called conv_jistoeuc(). There is no bounds checking on the > > > output buffer, which is created on the stack with alloca(). > > > > http://git.claws-mail.org/?p=claws.git;a=commit;h=d390fa07f5548f3173dd9cc13b233db5ce934c82 > > > > > > conv_jistoeuc > > > conv_euctojis > > > conv_sjistoeuc > > The original discoverer found a conv_jistoeuc issue, and then the > vendor apparently also found conv_euctojis and conv_sjistoeuc issues. > However, we don't see an indication that these issues arose in > independent ways. (Also, there is no vendor statement that > conv_euctojis or conv_sjistoeuc is exploitable.) It seems best to > assign CVE-2015-8614 to the combination of the conv_jistoeuc, > conv_euctojis, and conv_sjistoeuc issues. [...] Note that two of the bounds checks added in that commit are incorrect: 1. In conv_jistoeuc() the check uses > rather than <, which causes all conversions to return an empty string. This is presumably not a security issue, but is a regression. 3. In conv_euctojis() the comparison is with outlen - 3, but each pass through the loop uses up to 5 bytes and the rest of the function may add another 4 bytes. The comparison should presumably be '<= outlen - 9' or equivalently '< outlen - 8'. The first check is fixed by a later commit: http://git.claws-mail.org/?p=claws.git;a=commitdiff;h=e3ffcb455e0376053451ce968e6c71ef37708222 Ben. -- Ben Hutchings All the simple programs have been written, and all the good names taken. [ CONTENT OF TYPE application/pgp-signature SKIPPED ]
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