FYI, I managed to scrape together a spare machine for testing and the patch works fine here.
-Dennis ----- Original Message ---- From: Sam Varshavchik <mr...@courier-mta.com> To: Dennis Lou <dlou99 at yahoo.com> Cc: Nicolas <nicolas.martin at freesurf.fr>; mrsam-guest <mrsam-guest at alioth.debian.org>; sane-devel <sane-devel at lists.alioth.debian.org> Sent: Wednesday, June 25, 2008 3:20:22 PM Subject: Re: [sane-devel] Problem with libusb and 64 bits 2.6.25 kernel Dennis Lou writes: > The way I see it, Sam's buffer overflow concern is predicated on a > misbehaving device. I haven't witnessed it but it is possible given that > we're reverse engineering things rather than working from a formal spec. > Nicolas' buffer overflow concern is predicated on a misbehaving usb stack. > It's also possible, but probably less likely than Sam's concern. Which > to implement depends on how paranoid you are about the behavior of the > device and libusb. Clarification: my patch is needed to fix the following bug, referenced earlier in the thread: >>> Hi Dennis, >>> >>> A bug was opened a while back by Sam Varshavchik, concerning the pixma >>> backend for Canon ImageClass MF-4270, when compiled and used on a 64 >>> bits platform (no issue so far on 32 bits), details are given here: >>> >>> https://alioth.debian.org/tracker/?group_id=30186&atid=410366&func=detail&aid=310861 The original code issues a read request to libusb for more bytes than actually expected, and, apparently, on some hardware that causes a USB timeout, with Various Bad Things?, as I described in the bug. Besides a single scan now taking ~30 minutes, the resulting pnm is corrupted. By changing the code not to ask to read more than what's expected, that fixes both the original bug, and the overflow problem.
