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    SubjectRe: Deprecating .gz format on kernel.org
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    On Fri, 21 Mar 2003, Ville Herva wrote:

    > On Thu, Mar 20, 2003 at 06:14:53PM -0500, you [Hank Leininger] wrote:
    > >
    > > Right, but if the uncompressed file is what's signed, then you must
    > > waste either CPU uncompressing twice (once to verify, once to untar) or
    > > waste disk (to store the uncompressed file, then verify, then untar).
    >
    > bzip2 -d < foo.tar.bz2 | tee >(md5sum) | tar xf
    > or
    > bzip2 -d < foo.tar.bz2 | tee >(gpg --verify foo.tar.bz2.sig) | tar xf

    Yup, but (besides the tar tpyo you corrected later) this still isn't
    safe.

    1) gpg --verify won't be able to complete until it's seen all the unpacked
    tar file.

    2) During that time tar -xf - will be unpacking and writing.

    3) If the signature is bad, too late you've already unpacked it:
    -At best you need to blow away what you just unpacked.
    -Worse, it may have just (over)written real files in pwd other than
    the ones you think it should have.
    -Worst, if the tarfile is maliciously crafted to exploit tar (..'ing
    archive, symlink-following archive, or bad data which overflows
    tar), who-knows-what damage is already done. This might sound
    far-fetched, except that it already happens.

    ...But it sounds like the whole discussion is dead anyway. It would be
    at least slightly less off-topic on security-audit, perhaps we should
    move it there (http://lsap.org/mail.html). Or to alt.tinfoil.hat.

    Hank Leininger <hlein@progressive-comp.com>
    E407 AEF4 761E D39C D401 D4F4 22F8 EF11 861A A6F1
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