Re: [PATCH] firedtv: add parameter to fake ca_system_ids in CA_INFO

[Mauro Carvalho Chehab <mchehab@infradead.org>]

Stefan Richter wrote:

> The Digital Everywhere firmware have the shortcoming that ca_info_enq and
> ca_info are not supported. This means that we can never retrieve the correct
> ca_system_id to present in the CI message CA_INFO. Currently the driver uses
> the application id retrieved using app_info_req and app_info, but this id
> only match the correct ca_system_id as given in ca_info in some cases.
> This patch adds a parameter to the driver in order for the user to override
> what will be returned in the CA_INFO CI message. Up to four ca_system_ids can
> be specified.
> This is needed for users with CAMs that have different manufacturer id and
> ca_system_id and that uses applications that take this into account, like
> MythTV.

This seems an ugly workaround. The better seems to patch MythTV to accept a different
CAM.

> +static int num_fake_ca_system_ids;
...
> +		for (i = 0; i < num_fake_ca_system_ids; i++) {
> +			app_info[4 + i * 2] =
> +				(fake_ca_system_ids[i] >> 8) & 0xff;
...

NAK. If someone put an arbitrary high value for num_fake_ca_system_id's, it will write outside
the app_info array space, as the num_fake_ca_system_ids is not validated against the size
of app_info. Also, it makes no sense a negative value for this parameter.

-- 

Cheers,
Mauro