[sane-devel] Potential buffer overflow when scanning more than 16384 bytes per line with Brother MFC-6490CW

[Yuval Levy]

Thank you Allan.

TL;DR:  It was indeed a problem with the Brother backend, and even more
so with Brother's outdated downloads on its website.

On 15-06-27 06:35 PM, m. allan noah wrote:
> t/l/x/y are weird in scanimage, they are basically renamed options
> from the backend, and the '=' sign rules are different than other
> options.

Thanks for explaining the idiosyncrasy to me.  My view is that of a
naive user that longs for a consistent and efficient user interface
without knowing anything about the history.  Attached is a patch to the
scanimage man page that would have saved my time and hopefully will save
other users' time.

> if you don't specify an arg to -B, it defaults to 1 meg. If that does
> not solve your issue, then it sounds like a bug in the brother
> backend. You might try using another frontend to verify.

Indeed the problem was in the Brother backend, brscan3, distributed from
Brother's website.

On my machine was brscan3 version 0.2.11-5, dated June 5, 2012, still
linked today from the support page [1].

When searching for the backend today, I landed on [2] where I found a
newer version of the backend, 0.2.13-1, dated April 14, 2015.

I installed the newer version of the backend.  It deleted the
configuration files for the previous version (not very elegant), but it
fixed the bug.  No -B necessary.

Yuv


[1] <http://support.brother.com/g/s/id/linux/en/download_scn.html>
[2]
<http://support.brother.com/g/b/downloadlist.aspx?c=ca&lang=en&prod=mfc6490cw_all&os=128>



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