Re: [PATCH 1/9 v2] staging: dt3155: check put_user() return value

Simon Horman
2010-08-02T12:41:31Z

On Mon, Aug 02, 2010 at 12:31:12PM +0400, Kulikov Vasiliy wrote:
> put_user() return code was not checked for errors. To simplify the code
> fill local struct dt3155_read with data and copy it with single
> copy_to_user() call.
>
> Signed-off-by: Kulikov Vasiliy <segooon@gmail.com>
> ---
> drivers/staging/dt3155/dt3155_drv.c | 17 ++++++++---------
> 1 files changed, 8 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/staging/dt3155/dt3155_drv.c b/drivers/staging/dt3155/dt3155_drv.c
> index 7316996..4013f09 100644
> --- a/drivers/staging/dt3155/dt3155_drv.c
> +++ b/drivers/staging/dt3155/dt3155_drv.c
> @@ -745,10 +745,11 @@ static ssize_t dt3155_read(struct file *filep, char __user *buf,
> struct dt3155_status *dts = &dt3155_status[minor];
> struct dt3155_fbuffer *fb = &dts->fbuffer;
> struct frame_info *frame_info;
> + struct dt3155_read dt_read;
>
> /* TODO: this should check the error flag and */
> /* return an error on hardware failures */
> - if (count != sizeof(struct dt3155_read))
> + if (count != sizeof(dt_read))

I believe that sizeof(struct dt3155_read) is preferred,
so this change isn't needed and sizeof(struct dt3155_read)
should be used below (three times).

> {
> printk(KERN_INFO "DT3155 ERROR (NJC): count is not right\n");
> return -EINVAL;
> @@ -797,17 +798,15 @@ static ssize_t dt3155_read(struct file *filep, char __user *buf,
>
> /* make this an offset */
> offset = frame_info->addr - dts->mem_addr;
> + dt_read.offset = offset;
> + dt_read.frame_seq = fb->frame_count;
> + dt_read.state = dts->state;
> + memcpy(&dt_read.frame_info, frame_info, sizeof(frame_info));
>
> - put_user(offset, (unsigned int __user *)buf);
> - buf += sizeof(u32);
> - put_user(fb->frame_count, (unsigned int __user *)buf);
> - buf += sizeof(u32);
> - put_user(dts->state, (unsigned int __user *)buf);
> - buf += sizeof(u32);
> - if (copy_to_user(buf, frame_info, sizeof(*frame_info)))
> + if (copy_to_user(buf, &dt_read, sizeof(dt_read)))
> return -EFAULT;
>
> - return sizeof(struct dt3155_read);
> + return sizeof(dt_read);
> }
>
> static unsigned int dt3155_poll (struct file * filp, poll_table *wait)
> --
> 1.7.0.4