On 05.12.22 04:41, Wupeng Ma wrote:
From: Ma Wupeng <mawupeng1@xxxxxxxxxx>
While testing mlock, we have a problem if the len of mlock is ULONG_MAX.
The return value of mlock is zero. But nothing will be locked since the
len in do_mlock overflows to zero due to the following code in mlock:
len = PAGE_ALIGN(len + (offset_in_page(start)));
However this problem appear in multiple syscalls.
Since TASK_SIZE is the maximum user space address. The start or len of
mlock shouldn't be bigger than this. Function access_ok can be used to
check this issue, so return -EINVAL if bigger.
I assume this makes sure that what we document holds:
EINVAL (mlock(), mlock2(), and munlock()) The result of the addition
addr+len was less than addr (e.g., the addition may have
resulted in an overflow).
So instead of adding access_ok() checks, wouldn't be the right think to
do checking for overflows?
--
Thanks,
David / dhildenb
