Re: [PATCH] module: fix validate_section_offset() overflow bug on 64-bit

[Shuah Khan]

On 10/15/21 3:14 PM, Luis Chamberlain wrote:
> On Fri, Oct 15, 2021 at 02:57:41PM -0600, Shuah Khan wrote:
> > validate_section_offset() uses unsigned long local variable to
> > add/store shdr->sh_offset and shdr->sh_size on all platforms.
> > unsigned long is too short when sh_offset is Elf64_Off which
> > would be the case on 64bit ELF headers.
> >
> > Fix the overflow problem using the right size local variable when
> > CONFIG_64BIT is defined.
> >
> > Signed-off-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
>
> Thanks for doing this! I put this through the 0-day grinder.
>
> In the meantime, since this talks about a fix, can the commit log be a
> bit more descriptive about the impact of not applying the fix? In what
> situation would not having this patch applied create an issue? Is this
> theoretical or can an issue really happen. Has an issue gone
> undiscovered for a while, and if so what could the consequences
> have been all along?

I found this when I was adding an error message to print the offset and
size.

> And it would seem this issue was found through code inspection, not
> through a real bug, correct? If this can be clarified on the commit log
> as well that would be great!

Sent v2 with updated commit log.

thanks,
-- Shuah