From 32336c097b6a75cfb2d88fc281c560e78ebf3aea Mon Sep 17 00:00:00 2001 From: Peter Korsgaard Date: Thu, 27 Jan 2011 10:33:26 +0100 Subject: [PATCHv2] evdev: fix evdev_write return value on partial writes 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 and return -EINVAL if less than 1 struct was written, similar to how it is done in evdev_read. Signed-off-by: Peter Korsgaard --- Changes since v1: - Return -EINVAL on writes of length < sizeof(struct input_event), similar to how it's done in evdev_read. drivers/input/evdev.c | 5 ++++- 1 files changed, 4 insertions(+), 1 deletions(-) diff --git a/drivers/input/evdev.c b/drivers/input/evdev.c index c8471a2..1ee7d0f 100644 --- a/drivers/input/evdev.c +++ b/drivers/input/evdev.c @@ -321,6 +321,9 @@ static ssize_t evdev_write(struct file *file, const char __user *buffer, struct input_event event; int retval; + if (count < input_event_size()) + return -EINVAL; + retval = mutex_lock_interruptible(&evdev->mutex); if (retval) return retval; @@ -330,7 +333,7 @@ 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