Re: [linuxsh-dev] gUSA committed for 2.4.18

[Jeremy S. <js...@mv...>]

NIIBE Yutaka wrote:

> It's sad that our test coverage is bad.
> I've found a bug of __clear_user, fixed.
> I've committed gUSA implementation for 2.4.18.
>
> I'm testing.  After that, I will tag 2_4_18 and merge 2.4.19.

Hi Niibe,

I think the gUSA idea is really clever!  One suggestion though: would it
be possible to put in a few more checks (like limit the offset in the
SP to a relatively small number, and check that the current PC is within
the bounds specified by the implied arguments in r1 etc)?  That could help
reduce the chance that a frame/stack overflow bug being mistaken for a
gUSA operation (though I don't know that it matters much.)  BTW, when you
first proposed this you said you had some pushback from the general kernel
community; has there been any change in that?

Second: Even with the fix, there are still a couple __clear_user problems;
if there's no objection, I'd like to include the attached patch.  (First
hunk addresses the issue of r2 being uninitialized when you get to .Larea2
for a small clear; second hunk addresses a false termination of area 2.)

Thanks,
  --Jeremy