linux-kernel - Re: 2.6.36/2.6.37: broken compatibility with userspace input-utils ?

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]

Date:	Mon, 24 Jan 2011 21:29:02 -0800
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Mark Lord <kernel@...savvy.com>
Cc:	Linux Kernel <linux-kernel@...r.kernel.org>,
	linux-input@...r.kernel.org
Subject: Re: 2.6.36/2.6.37: broken compatibility with userspace input-utils ?

On Tue, Jan 25, 2011 at 12:04:10AM -0500, Mark Lord wrote:
> On 11-01-24 11:55 PM, Dmitry Torokhov wrote:
> > On Mon, Jan 24, 2011 at 11:37:06PM -0500, Mark Lord wrote:
> ..
> >> This results in (map->size==10) for 2.6.36+ (wrong),
> >> and a much larger map->size for 2.6.35 and earlier.
> >>
> >> So perhaps EVIOCGKEYCODE has changed?
> >>
> > 
> > So the utility expects that all devices have flat scancode space and
> > driver might have changed so it does not recognize scancode 10 as valid
> > scancode anymore.
> > 
> > The options are:
> > 
> > 1. Convert to EVIOCGKEYCODE2
> > 2. Ignore errors from EVIOCGKEYCODE and go through all 65536 iterations.
> 
> or 3. Revert/fix the in-kernel regression.
> 
> The EVIOCGKEYCODE ioctl is supposed to return KEY_RESERVED for unmapped
> (but value) keycodes, and only return -EINVAL when the keycode itself
> is out of range.

You are inventing rules.  You are requesting a scancode->keycode
mapping. If scancode is unknown/invalid for the device ioctl returns
-EINVAL.

> 
> That's how it worked in all kernels prior to 2.6.36,
> and now it is broken.  It now returns -EINVAL for any unmapped keycode,
> even though keycodes higher than that still have mappings.

For unmapped - yes, either KEY_RESERVED or KEY_UNKNOWN should be
returned. For invalid scancodes -EINVAL shoudl be returned. Scancodes
are not guaranteed to be continuous (and never have been for all devices
although there are still plenty of devices with continuous scancodes,
like atkbd).

> 
> This is a bug, a regression, and breaks userspace.
> I haven't identified *where* in the kernel the breakage happened,
> though.. that code confuses me.  :)
> 

-- 
Dmitry
--
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/