Re: [PATCH] evdev: fix evdev_write return value on partial writes
From: Baruch Siach <baruch@tkos.co.il>
Date: 2011-01-27 09:46:34
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
quoted hunk ↗ jump to hunk
--- 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 -