linux-kernel - Re: O2micro smartcard reader driver.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <200612122305.53767.oliver@neukum.org>
Date:	Tue, 12 Dec 2006 23:05:53 +0100
From:	Oliver Neukum <oliver@...kum.org>
To:	Eric Piel <Eric.Piel@...mplin-utc.net>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: O2micro smartcard reader driver.

Am Dienstag, 12. Dezember 2006 22:28 schrieb Eric Piel:

Hi

> Thanks a lot for reading my code, I didn't even hope that someone would! 
> I've corrected the copy_to_user (and copy_from_user) code. However I 
> don't know how to do locking for the concurrent ioctls. Indeed, I don't 
> think there is anything preventing two programs to call the driver at 
> the same time. Unfortunately, I've got no idea how to do the locking and 
> surprisingly couldn't find any ioctl code in the kernel doing locking. 
> Maybe I've just not looked at the right place, could you give a me some 
> hint how to do locking for ioctl's ?

I take it back. Reading your code again, it seems to me that it'll
never sleep. In this case you are protected by BKL. If not, you need
to use mutexes, just like eg. in drivers/usb/class/usblp.c

	HTH
		Oliver
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/