Revert "exynos_mem: an alternative temporary workaround for exynos-mem security hole"

This reverts commit 858bff06e4692191b05cb306204401d861f5adf0.
exynos-mem: Fix major security hole, + small fimc allow.

This fixes the exynos-mem device security hole. The driver allowed any user
to access all of the device's lowmem through the provided mmap functionality.

We create a small little framework collecting the actual CMA memory blocks
that exist on the device; they are the root cause of the existence of this device
driver. We white-list only the CMA memory spaces as parameters to the mmap
function and deny access to any other memory space requests.

We furthermore just allow access to the "s3c-fimc" memory block as this is
seemingly the only space which upon access denial actually breaks functionality.

This patch was modified to be suitable for Exynos 4210 by
Andrew Dodd <atd7@cornell.edu> from Andrei's original Exynos 4412 patch.

Change-Id: Ie5335c1ca81293dc071e919c00524f1e6765e70e
Signed-off-by: Andrew Dodd <atd7@cornell.edu>
opp: De-obscurify OPP structs and disclose find_device_opp

Move definitions of OPP structs in the header file so that its
members are public and the struct is no longer obscure.

Define interface for find_device_opp in the header file.
binfmt_elf.c: use get_random_int() to fix entropy depleting

Changes:
--------
v4->v3:
- s/random_stack_user()/get_atrandom_bytes()/
- Move this function to ahead of its use to avoid the predeclaration.

v3->v2:
- Tweak code comments of random_stack_user().
- Remove redundant bits mask and shift upon the random variable.

v2->v1:
- Fix random copy to check up buffer length that are not 4-byte multiples.

v3 can be found at:
http://www.spinics.net/lists/linux-fsdevel/msg59597.html
v2 can be found at:
http://www.spinics.net/lists/linux-fsdevel/msg59418.html
v1 can be found at:
http://www.spinics.net/lists/linux-fsdevel/msg59128.html

Thanks,
-Jeff

Entropy is quickly depleted under normal operations like ls(1), cat(1),
etc...  between 2.6.30 to current mainline, for instance:

$ cat /proc/sys/kernel/random/entropy_avail
3428
$ cat /proc/sys/kernel/random/entropy_avail
2911
$cat /proc/sys/kernel/random/entropy_avail
2620

We observed this problem has been occurring since 2.6.30 with
fs/binfmt_elf.c: create_elf_tables()->get_random_bytes(), introduced by
f06295b44c296c8f ("ELF: implement AT_RANDOM for glibc PRNG seeding").

/*
 * Generate 16 random bytes for userspace PRNG seeding.
 */
get_random_bytes(k_rand_bytes, sizeof(k_rand_bytes));

The patch introduces a wrapper around get_random_int() which has lower
overhead than calling get_random_bytes() directly.

With this patch applied:
$ cat /proc/sys/kernel/random/entropy_avail
2731
$ cat /proc/sys/kernel/random/entropy_avail
2802
$ cat /proc/sys/kernel/random/entropy_avail
2878

Analyzed by John Sobecki.

Signed-off-by: Jie Liu <jeff.liu@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Dilger <aedilger@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Arnd Bergmann <arnn@arndb.de>
Cc: John Sobecki <john.sobecki@oracle.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Ulrich Drepper <drepper@redhat.com>
Kernel Config Change.
WIFI + CONFIG + SOUND: ported WIFI global driver from 3.0.57 and more Restored GOVS and ROW added change to Audio Driver load, need to check with JB SAMMY.

WIFI toggle works now.
synced dorimanx configuration file