lkml.org 
[lkml]   [2023]   [Jan]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH 0/4] return EINVAL for illegal user memory range
From
On 05.12.22 04:41, Wupeng Ma wrote:
> From: Ma Wupeng <mawupeng1@huawei.com>
>
> 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

\
 
 \ /
  Last update: 2023-03-26 23:24    [W:0.135 / U:0.284 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site