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SubjectRe: [PATCH 5/9] staging: panel: check put_user() return value
On Fri, Jul 30, 2010 at 03:08:42PM +0400, Kulikov Vasiliy wrote:
> diff --git a/drivers/staging/panel/panel.c b/drivers/staging/panel/panel.c
> index f58da32..57f4946 100644
> --- a/drivers/staging/panel/panel.c
> +++ b/drivers/staging/panel/panel.c
> @@ -1589,25 +1589,30 @@ void lcd_init(void)
> static ssize_t keypad_read(struct file *file,
> char *buf, size_t count, loff_t *ppos)
> {
> -
> + int buflen = keypad_buflen;
> unsigned i = *ppos;
> char *tmp = buf;
> + int start = keypad_start;
>
> - if (keypad_buflen == 0) {
> + if (buflen == 0) {
> if (file->f_flags & O_NONBLOCK)
> return -EAGAIN;
>
> interruptible_sleep_on(&keypad_read_wait);
> if (signal_pending(current))
> return -EINTR;
> + buflen = keypad_buflen;
> }

Not sure what the intent was here, I think you're re-adjusting
the buffer's length in case something else was read. But then
I don't understand why buflen it not simply assigned after the
if() block.

The rest below looks fine otherwise.

>
> - for (; count-- > 0 && (keypad_buflen > 0);
> - ++i, ++tmp, --keypad_buflen) {
> - put_user(keypad_buffer[keypad_start], tmp);
> - keypad_start = (keypad_start + 1) % KEYPAD_BUFFER;
> + for (; count-- > 0 && (buflen > 0);
> + ++i, ++tmp, --buflen) {
> + if (put_user(keypad_buffer[start], tmp))
> + return -EFAULT;
> + start = (start + 1) % KEYPAD_BUFFER;
> }
> *ppos = i;
> + keypad_buflen = buflen;
> + keypad_start = start;
>
> return tmp - buf;
> }


Regards,
Willy



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