On Monday 14 May 2007 15:11, pradeep singh wrote:
> Hi,
> here is the code snippet to copy a socket address to kernel address space
> from user address space.
>
> int move_addr_to_kernel(void __user *uaddr, int ulen, void *kaddr)
> {
> if(ulen<0||ulen>MAX_SOCK_ADDR)
> return -EINVAL;
> if(ulen==0)
> return 0;
> if(copy_from_user(kaddr,uaddr,ulen))
> return -EFAULT;
> return audit_sockaddr(ulen, kaddr);
> }
>
> Ok, here is the query -
> What if the user address is actually mapped on to physical memory > 1 GB.
> I cannot figure out then how the socket address space will be copied
> without involving any temporary kernel mappings?And i also do not see any
> code involving creation of the temporary mappings in this case?
>
You already have the buffer mapped: somewhere in userspace. And this runs from
process context, thus you can access it's address space.
tavi
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