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Re: lircd daemon as regular user => device access problems




On Sun, Feb 12, 2017 at 1:47 PM, Simon McVittie <smcv@xxxxxxxxxx> wrote:
> On Sun, 12 Feb 2017 at 11:33:22 +0100, Alec Leamas wrote:
>> On 12/02/17 11:16, Bastien Roucaries wrote:
>> > Last time braille stuff break (brick) a FPGA device with a jtag adaptator (serial to jtag). So i really dislike package that bind to all char device.
>> >
>> > Btw if you do this you need a break on braille stuff...
>>
>> Now, we are not talking about all character devices, it's about USB-based
>> character devices. Does this address your concerns?
>>
>> If not, blacklisting probably is the easiest path - I'm happy to blacklist
>> any USB ids if you just provide them. Or, if that's better, relevant udev
>> info to make a matching rule.
>
> This is sounding a lot like ModemManager, which has recurring problems
> with the inability to distinguish between modems and non-modem
> serial-attached devices (especially since both will often use a commodity
> USB/serial converter with generic device IDs, like a FTDI or PL2303 device)
> without probing them by sending AT commands that could be interpreted in
> unintended ways by non-modems (like Braille devices, embedded devices'
> serial consoles, and Bastien's JTAG adapter).
>
> /lib/udev/??-mm-*.rules are probably of interest. ModemManager
> implements a whitelist (devices that are definitely modems), a blacklist
> (devices that are definitely not modems), and a greylist (devices that
> might be modems, but will only be probed by ModemManager if the user
> explicitly requests it via some GUI or CLI frontend).

It is the only solution. Thanks simon to point to something sane.

For FTDI/PL2303 I believe long term solution will be to install some
gui (with ncurses) that will allow to custumize the description string
in order to automagically whitelist (or assign some ID).

Bastien
>
>     S
>