[uml-devel] TT mode and vsyscall checking

[Blaisorblade <bla...@ya...>]

=46rom what I can see, while in SKAS mode access_ok_skas() was changed to a=
llow=20
reading from vsyscall page, while TT mode wasn't.

I'm not sure it that happened:

*) because TT mode already allowed that (access_ok_tt() currently accepts a=
ny=20
read) or
*) because TT mode is different in this regard.

But the more I think the more I conclude it's the first reason.

Anyway, I wanted to make sure because I'm fixing access_ok. Attached is pat=
ch=20
1, which joins common code and adds missing checking.

Later I'll maybe drop what is unneeded, for instance, range wrapping checki=
ng=20
seems not to be done on i386, and we just need to fail in copy_from_user() =
in=20
that case.

Switching copy_*_user() to use an unsigned type for the size, maybe a long =
(I=20
don't expect anything to actually need 64-bit, even on x64, though), would =
be=20
nice too.
=2D-=20
Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!".
Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894)
http://www.user-mode-linux.org/~blaisorblade