* [PATCH] evdev: fix evdev_write return value on partial writes
@ 2011-01-27 9:42 Peter Korsgaard
2011-01-27 9:46 ` Baruch Siach
0 siblings, 1 reply; 3+ messages in thread
From: Peter Korsgaard @ 2011-01-27 9:42 UTC (permalink / raw)
To: dmitry.torokhov, linux-input, baruch; +Cc: Peter Korsgaard
As was recently brought up on the busybox list
(http://lists.busybox.net/pipermail/busybox/2011-January/074565.html),
evdev_write doesn't properly check the count argument, which will
lead to a return value > count on partial writes if the remaining bytes
are accessible - Causing userspace confusion.
Fix it by only handling each full input_event structure, similar to how
it is done in evdev_read.
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
---
drivers/input/evdev.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
index c8471a2..61fa24e 100644
--- a/drivers/input/evdev.c
+++ b/drivers/input/evdev.c
@@ -330,7 +330,7 @@ static ssize_t evdev_write(struct file *file, const char __user *buffer,
goto out;
}
- while (retval < count) {
+ while ((retval + input_event_size()) <= count) {
if (input_event_from_user(buffer + retval, &event)) {
retval = -EFAULT;
--
1.7.2.3
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] evdev: fix evdev_write return value on partial writes
2011-01-27 9:42 [PATCH] evdev: fix evdev_write return value on partial writes Peter Korsgaard
@ 2011-01-27 9:46 ` Baruch Siach
2011-01-27 10:05 ` Peter Korsgaard
0 siblings, 1 reply; 3+ messages in thread
From: Baruch Siach @ 2011-01-27 9:46 UTC (permalink / raw)
To: Peter Korsgaard; +Cc: dmitry.torokhov, linux-input
Hi Peter,
On Thu, Jan 27, 2011 at 10:42:00AM +0100, Peter Korsgaard wrote:
> As was recently brought up on the busybox list
> (http://lists.busybox.net/pipermail/busybox/2011-January/074565.html),
> evdev_write doesn't properly check the count argument, which will
> lead to a return value > count on partial writes if the remaining bytes
> are accessible - Causing userspace confusion.
>
> Fix it by only handling each full input_event structure, similar to how
> it is done in evdev_read.
>
A Reporte-by here would be nice.
> Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
As I said on the Busybox list, applying this results in an endless
write(1, "test\n", 5) = 0
write(1, "test\n", 5) = 0
write(1, "test\n", 5) = 0
write(1, "test\n", 5) = 0
write(1, "test\n", 5) = 0
write(1, "test\n", 5) = 0
write(1, "test\n", 5) = 0
from the command
echo test > /dev/input/event0
write() should probably return -EINVAL here.
baruch
> ---
> drivers/input/evdev.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c
> index c8471a2..61fa24e 100644
> --- a/drivers/input/evdev.c
> +++ b/drivers/input/evdev.c
> @@ -330,7 +330,7 @@ static ssize_t evdev_write(struct file *file, const char __user *buffer,
> goto out;
> }
>
> - while (retval < count) {
> + while ((retval + input_event_size()) <= count) {
>
> if (input_event_from_user(buffer + retval, &event)) {
> retval = -EFAULT;
> --
> 1.7.2.3
>
--
~. .~ Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
- baruch@tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] evdev: fix evdev_write return value on partial writes
2011-01-27 9:46 ` Baruch Siach
@ 2011-01-27 10:05 ` Peter Korsgaard
0 siblings, 0 replies; 3+ messages in thread
From: Peter Korsgaard @ 2011-01-27 10:05 UTC (permalink / raw)
To: Baruch Siach; +Cc: dmitry.torokhov, linux-input
>>>>> "Baruch" == Baruch Siach <baruch@tkos.co.il> writes:
>> Fix it by only handling each full input_event structure, similar to
>> how it is done in evdev_read.
Baruch> A Reporte-by here would be nice.
Sorry, forgot. Dmitry, could you add it when you commit the patch.
>> Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Baruch> As I said on the Busybox list, applying this results in an endless
Baruch> write(1, "test\n", 5) = 0
Baruch> write(1, "test\n", 5) = 0
Baruch> write(1, "test\n", 5) = 0
Baruch> write(1, "test\n", 5) = 0
Baruch> write(1, "test\n", 5) = 0
Baruch> write(1, "test\n", 5) = 0
Baruch> write(1, "test\n", 5) = 0
Baruch> from the command
Baruch> echo test > /dev/input/event0
Baruch> write() should probably return -EINVAL here.
Indeed, like we do in evdev_read. Updated patch sent.
--
Bye, Peter Korsgaard
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2011-01-27 10:05 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2011-01-27 9:42 [PATCH] evdev: fix evdev_write return value on partial writes Peter Korsgaard
2011-01-27 9:46 ` Baruch Siach
2011-01-27 10:05 ` Peter Korsgaard
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.