Bug#583273: flegita: Crashes on startup

[Андрей Парамонов]

2012/5/17 Matej Vela <vela at debian.org>:
> On Fri, May 28, 2010 at 10:42:44PM +0200, Julien BLACHE wrote:
>> Андрей Парамонов <cmr.pent at gmail.com> wrote:
>>
>>> I've managed to get the following backtrace with hplip debug symbols:
>>>
>>> 0xb090304c in sane_hpaio_control_option (handle=0x8262800, option=10,
>>> action=SANE_ACTION_GET_VALUE, pValue=0x0,
>>>     pInfo=0xb34b21ac) at scan/sane/hpaio.c:2485
>>> 2485                        *pIntValue = hpaio->currentDuplex;
>>
>> I think we have a winner :-) Now you'll just have to figure out why
>> gnome-scan passes NULL here :/
>
> Andrey, can you try rebuilding libsane-hpaio with the patch below?  Or I can
> put together an (unofficial) package -- just let me know which dist/arch.
>
> This is what seems to be happening:
>
> (1) hplip-3.12.2/scan/sane/hpaio.c (sane_hpaio_open) initializes the option
>    descriptor array with zeros.  Most descriptors are later given actual
>    values (hpaioSetupOptions), but OPTION_DUPLEX (index 10) is initialized
>    only if duplex is active; if not, its .size is left as 0.
>
> (2) gnome-scan-0.6.2/modules/gsane-scanner.c (gss_option_get_value_by_index)
>    fetches the duplex option descriptor, and passes its .size without
>    checking to g_malloc0.  For a size of 0, g_malloc0 is defined to return
>    NULL.  This is again passed without checking to sane_control_option,
>    which segfaults as soon as it tries to store the return value there.
>
> It's a given that gnome-scan would be better off with more sanity checks,
> but I think the right thing to do is for libsane-hpaio to initialize the
> OPTION_DUPLEX descriptor unconditionally, to ensure that the return value
> from sane_get_option_descriptor is valid for all callers.
>
> (I haven't worked with SANE before, and don't have a scanner to test with,
> so take all this with a large grain of salt. :-)
>
> Cheers,
>
> Matej

I've checked your patch and it works! Flegita appears to be really
nice program ;-)

Thanks,
Andrey Paramonov