On Fri, Aug 7, 2015 at 8:21 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, clear_user, compatibility accessors (copy_in_user and
> _unaligned), 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.
>
> Only build tested for arm, blackfin, metag, microblaze, openrisc,
> parisc, powerpc, sh, sparc, tile, i386 & xtensa.
>
> All arches were audited for the appropriate exports, only score is known
> to still be missing some.
>
> Changes in v2:
> - Add arch exports (patches 1-4).
> - Reorder patches slightly.
> - Patch 9: Drop strlen_user test. Microblaze doesn't define it, and
> nothing actually uses it. IMO it should be removed, and there's no
> point testing it in the mean time.
> - Patch 10: Conditionalise on CONFIG_COMPAT, otherwise it breaks build
> on some 32-bit arches e.g. i386 (kbuild test robot).
> - Patch 10: Add testing of _unaligned accessors, which are also
> conditional upon CONFIG_COMPAT.
> - Patch 11: Only test csum_partial_copy_from_user #ifndef
> _HAVE_ARCH_COPY_AND_CSUM_FROM_USER, fixing powerpc64 build (Stephen
> Rothwell)
Thanks for the fixes!
Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
-Kees
>
> James Hogan (11):
> microblaze: Export __strnlen_user to modules
> nios2: Export strncpy_from_user / strnlen_user to modules
> openrisc: Export __clear_user to modules
> xtensa: Export __strnlen_user to modules
> test_user_copy: Check legit kernel accesses
> test_user_copy: Check unchecked accessors
> test_user_copy: Check __copy_{to,from}_user_inatomic()
> test_user_copy: Check __clear_user()/clear_user()
> test_user_copy: Check user string accessors
> test_user_copy: Check user compatibility accessors
> test_user_copy: Check user checksum functions
>
> arch/microblaze/kernel/microblaze_ksyms.c | 1 +
> arch/nios2/mm/uaccess.c | 2 +
> arch/openrisc/kernel/or32_ksyms.c | 1 +
> arch/xtensa/kernel/xtensa_ksyms.c | 1 +
> lib/test_user_copy.c | 251 ++++++++++++++++++++++++++++++
> 5 files changed, 256 insertions(+)
>
> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Michal Simek <monstr@xxxxxxxxx>
> Cc: Ley Foon Tan <lftan@xxxxxxxxxx>
> Cc: Jonas Bonn <jonas@xxxxxxxxxxxx>
> Cc: Chris Zankel <chris@xxxxxxxxxx>
> Cc: Max Filippov <jcmvbkbc@xxxxxxxxx>
> Cc: nios2-dev@xxxxxxxxxxxxxxxxxxxxxx
> Cc: linux@xxxxxxxxxxxxxxxxxx
> Cc: linux-xtensa@xxxxxxxxxxxxxxxx
> --
> 2.3.6
>
--
Kees Cook
Chrome OS Security
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