Re: linux-next: Tree for July 30

Dmitry Torokhov
2008-07-31T19:42:34Z

On Thu, Jul 31, 2008 at 03:24:02PM -0400, Dmitry Torokhov wrote:
> On Thu, Jul 31, 2008 at 12:10:40PM -0700, Linus Torvalds wrote:
> >
> > Sorry, but you're simply wrong.
> >
> > If somebody has the commit that broke user space, that commit will be
> > _reverted_ unless it's fixed. It's that simple. The rules are: we don't
> > knowingly break user space.
> >
>
> We have 3 options now:
>
> 1. Never change KEY_MAX and dont add any new key definitions.
> 2. Introduce a new ioctl and have all wel-behaving programs rewritten
> to support it.
> 3. Fix userspace driver (patch is available).
>
> Gioventhe fact that I wanted that change to go when .28 opens and it
> will really hit users in 6+ months I'd still like to have 3.
>

I guess we could do something like the below, but it is soooo ugly...

Input: paper over a bug in Synaptics X driver

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
---

drivers/input/evdev.c | 14 +++++++++++++-
1 files changed, 13 insertions(+), 1 deletions(-)

diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index 2d65411..c78a63b 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -736,8 +736,10 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0))) {

unsigned long *bits;
+ unsigned int buf_len = _IOC_SIZE(cmd);
int len;

+
switch (_IOC_NR(cmd) & EV_MAX) {

case 0: bits = dev->evbit; len = EV_MAX; break;
@@ -751,7 +753,17 @@ static long evdev_do_ioctl(struct file *file, unsigned int cmd,
case EV_SW: bits = dev->swbit; len = SW_MAX; break;
default: return -EINVAL;
}
- return bits_to_user(bits, len, _IOC_SIZE(cmd), p, compat_mode);
+
+ if ((_IOC_NR(cmd) & EV_MAX) == EV_KEY && buf_len == 0x1ff) {
+ printk(KERN_WARNING
+ "evdev.c(EVIOCGBIT): Detected suspicious "
+ "buffer size 0x1ff, limiting output to 64 "
+ "bytes. Make sure you are not using "
+ "EVIOCGBIT(EV_KEY, KEY_MAX)\n");
+ buf_len = 64;
+ }
+
+ return bits_to_user(bits, len, buf_len, p, compat_mode);
}

if (_IOC_NR(cmd) == _IOC_NR(EVIOCGKEY(0)))