On Wed, Aug 5, 2015 at 8:48 AM, James Hogan <james.hogan@xxxxxxxxxx> wrote:
> These patches extend the test_user_copy test module to handle lots more
> cases of user accessors which architectures can override separately, and
> in particular those which are important for checking the MIPS Enhanced
> Virtual Addressing (EVA) implementations, which need to handle
> overlapping user and kernel address spaces, with special instructions
> for accessing user address space from kernel mode.
>
> - Checking that kernel pointers are accepted when user address limit is
> set to KERNEL_DS, as done by the kernel when it internally invokes
> system calls with kernel pointers.
> - Checking of the unchecked accessors (which don't call access_ok()).
> Some of the tests are special cased for EVA at the moment which has
> stricter hardware guarantees for bad user accesses than other
> configurations.
> - Checking of other sets of user accessors, including the inatomic user
> copies, copy_in_user, clear_user, the user string accessors, and the
> user checksum functions, all of which need special handling in arch
> code with EVA.
>
> Tested on MIPS with and without EVA, and on x86_64.
>
> James Hogan (7):
> test_user_copy: Check legit kernel accesses
> test_user_copy: Check unchecked accessors
> test_user_copy: Check __clear_user()/clear_user()
> test_user_copy: Check __copy_in_user()/copy_in_user()
> test_user_copy: Check __copy_{to,from}_user_inatomic()
> test_user_copy: Check user string accessors
> test_user_copy: Check user checksum functions
>
> lib/test_user_copy.c | 221 +++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 221 insertions(+)
>
> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Ooooh! Nice! This is great, thank you. :) Great to hear it helped find
a bug too. :)
I'm wondering if we need to macro-ize any of these. Probably not, but
it just feels like there's a lot of repeated stuff now. But I think
it's a bit of an illusion since each test is ever so slightly
different from the others.
Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
-Kees
--
Kees Cook
Chrome OS Security
