Date: Mon, 29 Sep 2014 10:47:32 -0500 From: "Kobrin, Eric" <ekobrin@...mai.com> To: "oss-security@...ts.openwall.com" <oss-security@...ts.openwall.com> CC: "chet.ramey@...e.edu" <chet.ramey@...e.edu>, Florian Weimer <fweimer@...hat.com> Subject: Re: Array importing in bash 4.3 (was: Re: Fwd: Non-upstream patches for bash) On Sep 29, 2014, at 10:42 AM, Florian Weimer <fweimer@...hat.com> wrote: >> From: Florian Weimer <fweimer@...hat.com> >> >> Note that if you ship 4.3, you might want to reevaluate a decision to >> enable array variable import from the environment. > > I changed the subject because I'm sure this parenthetical comment got lost. > > Fortunately, in bash 4.3 (patchlevel 25), you cannot just -DARRAY_EXPORT > and get array variable import/export. The code doesn't compile, and if > you fix that, it does not link, and if you fix that, well, you end up > with the following issue. But I doubt anybody has done this, so it's > not a vulnerability (yet) and does not need CVE assignment etc. > > The array import/export feature allows one to export and import > variables while preserving their array status. Unfortunately, it > enables this: > > $ env -i 'FOO=([$(echo broken > /dev/tty)]=a)' ./bash -c true > broken > ./bash: =a: bad array subscript > > As I said, it is currently not an issue, but it's probably best not to > enable this in the future at all, or use it with another form of mangling. > > -- > Florian Weimer / Red Hat Product Security This code also reveals a difference from the function export code. The ARRAY_EXPORT code frees temp_string after using it. The function export code mallocs, but never frees it. That behavior predates the recent patches. -- Eric Kobrin
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