Date: Mon, 3 Nov 2014 11:05:43 +0000 From: mancha <mancha1@...o.com> To: oss-security@...ts.openwall.com Cc: Christian.Spieler@...nline.de Subject: Re: unzip -t crasher On Mon, Nov 03, 2014 at 07:42:06AM +0000, mancha wrote: > On Sun, Nov 02, 2014 at 07:06:40PM +0100, Jakub Wilk wrote: > > Latest American fuzzy lop tarball contains a zip file that > > crashes unzip -t: > > > > $ unzip -qt afl-0.43b/docs/samples/unzip_t_malloc.zip foo/: > > mismatching "local" filename (/UT), continuing with "central" > > filename version *** Error in `unzip': free(): corrupted unsorted > > chunks: 0x00000000015d0170 *** > > > > I'm not sure if inclusion of said zip file was intentional, but since > > the cat is already out of the bag, I thought I'll let you know. > > Cats shouldn't be in bags, anyways. > > The crasher has an OS/2 extra field that claims to have a compressed > block size of 52735 bytes and an uncompressed block size of 127 bytes. > > The attached patch against UnZip 6.0 ensures, within extra fields, > size(compressed) <= size(uncompressed) and should fix this issue. > > --mancha > > PS If the attachment gets mangled, it's also at: > http://sf.net/projects/mancha/files/sec/unzip-6.0_overflow.diff This buggy code path is traversed when a ZIP archive has <<extra fields>> with blocks that are uncompressed (i.e. using the STORED method). A better solution than my last patch or malloc'ing max(), is returning an invalid compressed data error when size(compressed)!= size(uncompressed) for these cases. The attached patch does just that. Comments welcome. Cheers. --mancha PS I have been CC'ing Christian Spieler via the only email I could find online. I've not gotten bounces so it might still be active. View attachment "unzip-6.0_overflow2.diff" of type "text/plain" (1475 bytes) Content of type "application/pgp-signature" skipped
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