Re: [PATCH v3] vsprintf: Prevent crash when dereferencing invalid pointers

Sergey Senozhatsky
2018-03-17T01:29:41Z

On (03/16/18 09:55), Petr Mladek wrote:
[..]
> I am not sure if it is worth it. I think that we would catch 99% of
> problems by checking the first byte.
>
> This patch was motivated by a code clean up rather than bug reports.

OK. Then I think we really need this "the patch is just good enough" line
in the commit message and a big comment in the source code.

Another idea (just an idea) - for some pointers we know the address range
we are going to access and can check the first and the last byte. E.g. for
UUID it's check_access(ptr) and check_access(ptr + len), and so on. Won't
work for string() in general case, tho.

-ss