On Thu, 2004-10-14 at 12:46, mohanlal jangir wrote:
> I have an small program. In this program, a pointer to struct data (in user
> space) is received in function make_local_copy (in kernel) using ioctl. In
> function make_local_copy, I want to make a local copy using copy_from_usr. I
> think, accessing p_usr_data->p_len in second call to copy_from_usr in this
> program is incorrect. Can someone confirm it?
>
> struct data {
> int len;
> int *p_len;
> };
>
> struct data* make_local_copy(unsigned long arg) {
> struct data *p_usr_data = (struct data*)arg;
> struct data *p_kernel_data =
> (struct data*) kmalloc(sizeof(struct data), GFP_KERNEL);
>
> copy_from_usr(p_kernel_data, p_usr_data, sizeof(*p_usr_data));
>
> p_kernel_data->p_len =
> (int*) kmalloc(p_kernel_data->len, GFP_KERNEL);
>
> copy_from_usr(p_kernel_data->p_len,
> p_usr_data->p_len, p_kernel_data->len);
> /* ^^^^^^^^^^^^^ */
shud'nt u be checking the return value of copy_from_user to make
sure the copy was successfull in BOTH the cases???
> return p_kernel_data;
> }
>
> Regards
> Mohanlal
>
>
> --
> Kernelnewbies: Help each other learn about the Linux kernel.
> Archive: http://mail.nl.linux.org/kernelnewbies/
> FAQ: http://kernelnewbies.org/faq/
>
--
Kernelnewbies: Help each other learn about the Linux kernel.
Archive: http://mail.nl.linux.org/kernelnewbies/
FAQ: http://kernelnewbies.org/faq/
