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RE: fsfs: Segfault when rep line lists the all-zeroes checksum

From: Bert Huijben <bert_at_qqmail.nl>
Date: Tue, 30 Aug 2016 12:42:14 +0200

> -----Original Message-----
> From: Daniel Shahaf [mailto:d.s_at_daniel.shahaf.name]
> Sent: dinsdag 30 augustus 2016 03:06
> To: Stefan Fuhrmann <stefanfuhrmann_at_alice-dsl.de>
> Cc: dev_at_subversion.apache.org
> Subject: Re: fsfs: Segfault when rep line lists the all-zeroes checksum
>
> Stefan Fuhrmann wrote on Mon, Aug 29, 2016 at 22:10:07 +0200:
> > On 29.08.2016 18:57, Daniel Shahaf wrote:
> > >Line 801 sets CHECKSUM to NULL (as promised by
> svn_checksum_parse_hex()'s
> > >docstring), line 803 dereferences it unconditionally.
> > I vaguely remember that we use(d) all-0 checksums
> > as a 'no checksum' indicator. There may have been
> > some mix-up when rep structure got flattened.
>
> The all-zeroes checksum compares equal to any other checksum.

I would guess that the all 0 checksum is *also* the checksum of some very unlikely data, so users might be able to trigger this under some very unusual circumstances.

        Bert
Received on 2016-08-30 12:42:25 CEST

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