This will be used in subsequent CLs to support PD software sync. For
now, only devidx=0 is used.
This changes the external vboot API, so must be checked in at the same
time as changes to the u-boot and depthcharge implementations. For
now, those implementations should simply check if devidx=0 and fail if
it's not.
BUG=chrome-os-partner:30079
BRANCH=none
TEST=make runtests
CQ-DEPEND=CL:208195,CL:208196
Change-Id: Iad3be9d676ac224c4582669bcd67176b39f75c73
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/208210
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
For displaying GBB images on panels with different dimension, X86 has VESA mode
and VBIOS to scale automatically but ARM does not have such mode settings. If we
install a larger panel on ARM platforms, current firmware will render the
screens in left-top corner and leave black borders in right-bottom corner.
To render images correctly, vboot library has to send out the expected dimension
(similar to the VESA mode) so display provider can scale or shift images.
BUG=chrome-os-partner:28494
TEST=emerge-nyan vboot_reference
CQ-DEPEND=CL:199051,CL:199045
BRANCH=none
Change-Id: I6d60f755ca2bcbd3135631d7624a8a4a4cff68b1
Reviewed-on: https://chromium-review.googlesource.com/199043
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Tested-by: Hung-Te Lin <hungte@chromium.org>
Commit-Queue: Hung-Te Lin <hungte@chromium.org>
We don't allow ENTER from a USB keyboard as the confirmation
in the switch from normal to developer mode.
For devices that have a physical recovery button, we require
a recovery button press instead. For other devices, we
require that ENTER be pressed on the internal keyboard.
This prevents an "evil keyboard" attack in which a USB keyboard
(or other USB device pretending to be a keyboard) sends a
control-D/ENTER sequence shortly after every boot (followed
by more evil keys). In that situation, when users power-on in
recovery mode, they will be forced to dev mode even if it
was not their intention. Further attacks are easy at
that point.
TESTING. On a panther device:
1. powered on with recovery button pressed -> booted in recovery mode
2. pressed control-D on external USB keyboard -> got to ToDev? screen
3. pressed ENTER -> system beeped
4. pressed recovery button -> system rebooted in DEV mode
... all as expected
Also:
1. powered on with recovery button pressed and HELD recovery button
2. pressed control-D -> system beeped
BUG=chrome-os-partner:21729
TEST=manual (see commit message)
BRANCH=none
CQ-DEPEND=CL:182420,CL:182946,CL:182357
Change-Id: Ib986d00d4567c2d447f8bbff0e5ccfec94596aa7
Reviewed-on: https://chromium-review.googlesource.com/182241
Reviewed-by: Luigi Semenzato <semenzato@chromium.org>
Tested-by: Luigi Semenzato <semenzato@chromium.org>
Commit-Queue: Luigi Semenzato <semenzato@chromium.org>
TEST=Built and booted Peppy. Ran flashrom from user space and
verified the EC firmware was updated after reboot.
CQ-DEPEND=CL:172651, CL:172652, CL:178324
BRANCH=none
BUG=chromium:325286
Signed-off-by: Daisuke Nojiri <dnojiri@chromium.org>
Change-Id: Ia73da70dbf3abb5ced48666e86715c8d24a431a0
Reviewed-on: https://chromium-review.googlesource.com/172635
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Tested-by: Daisuke Nojiri <dnojiri@google.com>
Commit-Queue: Daisuke Nojiri <dnojiri@google.com>
Add checks that the vboot library does not leak memory. This works by
tracking VbExMalloc() calls and making sure that they have an associated
VbExFree().
Adjust host_signature to use VbExFree() instead of free(), so that this
scheme works correctly for existing code.
BUG=chrome-os-partner:21115
BRANCH=pit
TEST=FEATURES=test emerge-peach_pit vboot_reference
Change-Id: I6ccccfbcc162fc43fb75862cd0eddad78ce8b18a
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/66175
At present reading data from storage in Vboot is a little fragmented. For
the firmware image, we expect the boot loader to handle this. For the disk
we have a block-level API. For the GBB (which also sits in the firmware
image) we expect the entire thing to be read before Vboot is called.
Add the concept of a region, and an API to read from a region. At present,
and most pressing, is reading from a GBB region. In the future this could
be extended to other parts of the firmware or even the disk.
Move all access to the GBB into this API so that the boot loader can provide
either a GBB region in one large contiguous chunk, or a function to deal with
read requests from vboot.
The call to VbExRegionRead() is behind a flag since not all boot loaders
support it yet.
The main change for boot loaders which don't support this new API is that
vboot will do more behind the scenes. For example, it will allocate memory
for chunks of data that it reads from the GBB, rather than just accessing it
directly. This approach is considerably simpler than trying to pass char **
everywhere and have vboot decide whether something needs to be allocated or
not.
The tests are updated, mainly to include setting up a GBB structure
accessible from VbCommonParams, which is now required by the firmware and
kernel functions. In normal operation this is set up at the start of
VbLoadFIrmware() and VbSelectAndLoadKernel() but for tests which call
children of these functions directly, the GBB structure must be set up
manually by the test.
BUG=chrome-os-partner:21115
BRANCH=none
TEST=manual
FEATURES=test sudo -E emerge vboot_reference
Change-Id: If2b8bbe467fdbd643239d8d9b5d7aa98df4d286f
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/63336
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/167361
At present reading data from storage in Vboot is a little fragmented. For
the firmware image, we expect the boot loader to handle this. For the disk
we have a block-level API. For the GBB (which also sits in the firmware
image) we expect the entire thing to be read before Vboot is called.
Add the concept of a region, and an API to read from a region. At present,
and most pressing, is reading from a GBB region. In the future this could
be extended to other parts of the firmware or even the disk.
Move all access to the GBB into this API so that the boot loader can provide
either a GBB region in one large contiguous chunk, or a function to deal with
read requests from vboot.
The call to VbExRegionRead() is behind a flag since not all boot loaders
support it yet.
The main change for boot loaders which don't support this new API is that
vboot will do more behind the scenes. For example, it will allocate memory
for chunks of data that it reads from the GBB, rather than just accessing it
directly. This approach is considerably simpler than trying to pass char **
everywhere and have vboot decide whether something needs to be allocated or
not.
The tests are updated, mainly to include setting up a GBB structure
accessible from VbCommonParams, which is now required by the firmware and
kernel functions. In normal operation this is set up at the start of
VbLoadFIrmware() and VbSelectAndLoadKernel() but for tests which call
children of these functions directly, the GBB structure must be set up
manually by the test.
BUG=chrome-os-partner:21115
BRANCH=none
TEST=manual
FEATURES=test sudo -E emerge vboot_reference
Change-Id: I2c19e9dc2ed602d0642bbf4f7d27f79fe9fad873
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/63336
Reviewed-by: Randall Spangler <rspangler@chromium.org>
These were macros that were never used, or that were only set to one thing and
could be substituted up front.
I left in code guarded by the HAVE_ENDIAN_H and HAVE_LITTLE_ENDIAN macros even
though those are never defined because they guard a reportedly significantly
faster implementation of some functionality, at least according to a comment
in the source. It would be a good idea to enable that code path and see if it
really does make a big difference before removing it entirely.
BUG=None
TEST=Built for Link, Daisy, and the host with FEATURES=test. Built depthcharge
for Link and booted in normal mode.
BRANCH=None
Change-Id: I934a4dd0da169ac018ba07350d56924ab88b1acc
Signed-off-by: Gabe Black <gabeblack@google.com>
Reviewed-on: https://gerrit.chromium.org/gerrit/45687
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Commit-Queue: Gabe Black <gabeblack@chromium.org>
Tested-by: Gabe Black <gabeblack@chromium.org>
This makes it more obvious which modules and VbEx*() functions must be
implemented to call these entry points.
This change only moves functions between modules and adds two
link-test binaries; it doesn't change any functionality.
BUG=chromium-os:39262
BRANCH=none
TEST=make && make runtests
Change-Id: If3edf0b1989b631f0e7ad18de7ccdad8315181b5
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/44076
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
This removes the need to load the EC code at all when the precomputed
hash matches.
BUG=chrome-os-partner:17606
BRANCH=spring
TEST=wouldn't that be nice
Change-Id: If4438b9db8b1449b8fd4d90ef3acb3bbec5e09a0
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/42567
Make sure all Tlcl users benefit from the new retry logic.
BUG=None
TEST=daisy build, manual testing of racing tpmc loops
BRANCH=None
Change-Id: I8e9656a65b5d6b45694c1c8bceb95f54f7c751bb
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/39525
Reviewed-by: Luigi Semenzato <semenzato@chromium.org>
If there were any errors communicating with the TPM at the OS layer
(open, read, write failures), the library would immediately exit, not
allowing the caller to make any decisions about how to handle it. This
introduces a way to initialize the library so that errors will get passed
back up to the caller instead of unceremoniously exiting.
Setting the environment variable "TPM_NO_EXIT=1" enables the feature. To
avoid needing to implement supporting functions in all backends, the
feature is currently limited to just the Tlcl stub implementation.
In the case of mount-encrypted, it can now survive the kernel returning
read/write failures. In the past it had only worked around having open
fail, but that has now been replaced with more sensible logic instead of
the environment variable trickiness.
BUG=chrome-os-partner:15960
TEST=daisy built with an always-failing kernel driver, u-boot builds too
BRANCH=None
Change-Id: Ic7b217017537980f9c239d678067398613045676
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/38791
Reviewed-by: Luigi Semenzato <semenzato@chromium.org>
This option is disabled per default and can be enabled with
crossystem dev_boot_legacy=1
or by setting the GBB flag
GBB_FLAG_FORCE_DEV_BOOT_LEGACY 0x00000080
BUG=chrome-os-partner:6108
TEST=crossystem dev_boot_legacy=1
boot to dev mode screen, press CTRL-L, see SeaBIOS start
(other CLs needed)
BRANCH=link
Signed-off-by: Stefan Reinauer <reinauer@chromium.org>
Change-Id: I593d2be7cff5ca07b8d08012c4514a172bd75a38
Reviewed-on: https://gerrit.chromium.org/gerrit/31265
Reviewed-by: Stefan Reinauer <reinauer@chromium.org>
Tested-by: Stefan Reinauer <reinauer@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Commit-Ready: Stefan Reinauer <reinauer@chromium.org>
This changes the signature of the function above so that it takes an additional
parameter that specifies which EC image vboot wants. This is better than making
U-Boot decide because U-Boot doesn't really keep track of which version it is
(it peeks at internal vboot data) and vboot does.
Also, some consts were removed from the image pointer pointer. The pointer
itself will be changed in the body of the function to tell vboot where the EC
has been loaded, and the contents of the buffer will be changed because U-Boot
will have to actually load the EC there.
BUG=chrome-os-partner:11148
TEST=Built vboot_reference, vboot_reference-firmware, chromeos-u-boot, and
chromeos-bootimage for Daisy and Link and saw them complete successfully with
and without the signature for U-Boot's version of this function being updated.
That works because the function isn't actually being used yet.
Change-Id: I2814c8210eb5b3d965bb8bbf23c0f283f9e44c90
Signed-off-by: Gabe Black <gabeblack@google.com>
Reviewed-on: https://gerrit.chromium.org/gerrit/27755
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Commit-Ready: Gabe Black <gabeblack@chromium.org>
Tested-by: Gabe Black <gabeblack@chromium.org>
The VbExTrustEC function should be implemented in the BIOS, not the vboot
library. Also, weak references don't seem to work with our linker, so we'll
have to just require it always.
BUG=chrome-os-partner:9953
TEST=none
This must go in with a simultaneous change to U-Boot. The only test is
whether or not everything continues to compile.
Change-Id: I8a5ccb167eec3bcacbe892cf0bdcfe550a1f57d6
Reviewed-on: https://gerrit.chromium.org/gerrit/25557
Tested-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Commit-Ready: Bill Richardson <wfrichar@chromium.org>
BUG=chrome-os-partner:7428
TEST=manual
Switch to dev-mode, turn it on, see how long it takes.
With gbb.flags == 1 (factory mode), it should take 2 seconds.
(You'll see a warning on the screen if gbb.flags is nonzero)
With gbb.flags == 0 (after factory install), it should take 30 seconds.
You should hear two beeps at 20 seconds.
Change-Id: I4f14128b87d3482e291b1b40a11a6d27c72c1ad1
Reviewed-on: https://gerrit.chromium.org/gerrit/14534
Tested-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-by: Stefan Reinauer <reinauer@chromium.org>
Commit-Ready: Bill Richardson <wfrichar@chromium.org>
The Makefile requires a few defines and isn't very friendly if they are
missing. This adds some warnings which should alert as to what is wrong.
BUG=chromium-os:16808
TEST=emerge vboot_reference-firmware for tegra2-seaboard, x86-mario
Change-Id: Id3b20365cfcc7f0aa7d984b33b6a0906ae0d44a5
Reviewed-on: https://gerrit.chromium.org/gerrit/11548
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
This enables us to support playing sounds in the background if the BIOS
allows it, so we don't have to block while beeping is happening. The new
declaration is:
VbError_t VbExBeep(uint32_t msec, uint32_t frequency);
If the audio codec can run in the background, then:
zero frequency means OFF, non-zero frequency means ON
zero msec means return immediately, non-zero msec means delay (and
then OFF if needed)
else:
non-zero msec and non-zero frequency means ON, delay, OFF, return
zero msec or zero frequency means do nothing and return immediately
The return value is used by the caller to determine the capabilities. The
implementation should always do the best it can if it cannot fully support
all features - for example, beeping at a fixed frequency if frequency
support is not available. At a minimum, it must delay for the specified
non-zero duration.
Currently, VbExBeep() is called only when displaying the dev-mode screen.
BUG=none
TEST=manual
I've tested on x86 and ARM, all timeouts and noises work as before.
Note that ARM and coreboot will require a corresponding change to their
VbExBeep() implementations, which will have to be handled with separate,
simultaneous CLs.
Change-Id: I3417ae4b99d9d0aee63f2ccaeed39b61d4333e5d
Reviewed-on: http://gerrit.chromium.org/gerrit/8234
Tested-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-by: Stefan Reinauer <reinauer@google.com>
The vboot library needs to decompress the images so that it can handle those
that are special cases (like rendering the HWID). This means that 1) it
needs access to the BIOS' native decompression routine, and 2) that
VbExDisplayImage() only needs to handle the uncompressed native-format image
and doesn't need to know about how the image is packed in the GBB.
BUG=chromium-os:19134
TEST=manual
This requires a change to vboot_api.h, which requires a (simultaneous)
matching change to the BIOS, at least for U-Boot, which builds separately.
I've made that change and run the "vbexport_test display" command from the
modified U-Boot, but that also requires a change to the way U-Boot is built
so that I can get at the U-Boot commandline.
Change-Id: I449fb467cd3a68e742f27ec41b95d52685459d89
Reviewed-on: http://gerrit.chromium.org/gerrit/6129
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Tested-by: Bill Richardson <wfrichar@chromium.org>
Third time's the charm. Now that we've moved to u-boot-next, this
won't break the ARM build.
BUG=chromium-os:17006
TEST=make && make runtests; emerge vboot_reference; emerge-tegra2_seaboard chromeos-bootimage
Change-Id: Ib4fa26c7a23868dd2ffd2b321ee8dc08c66ea322
Original-Change-Id: I771085dcdf79d9592de64f35e3b758111a80dd9f
Original-Reviewed-on: http://gerrit.chromium.org/gerrit/3263
Original-Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-on: http://gerrit.chromium.org/gerrit/3803
Tested-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
This reverts commit 0184886c8cb35e8e01d610622df448a7cb063e06
(This works with uboot-next, but not uboot, which doesn't implement its half of the new wrapper API. So rolling back to leave uboot working.
Change-Id: I1f9e3c63e5bbdb20b9195cd68787bef89f24afee
Reviewed-on: http://gerrit.chromium.org/gerrit/3588
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Tested-by: Randall Spangler <rspangler@chromium.org>
This is part 3 of the vboot wrapper API refactoring. It replaces the
function calls to utility.c functions with new API calls. (It also
fixes up some integer type mismatches in cryptolib that were causing
warnings on the H2C build; those had been fixed a while ago in H2C but
hadn't been propagated across.)
This is a re-commit of the original; I've verified it compiles on both
x86-alex and tegra2, for both vboot_reference and
vboot_reference-firmware, now that the patch from
1c1a883bc7 is checked in.
BUG=chromium-os:17006
TEST=make && make runtests, and emerged on both x86-alex and tegra2
Original-Change-Id: I771085dcdf79d9592de64f35e3b758111a80dd9f
Original-Reviewed-on: http://gerrit.chromium.org/gerrit/3263
Original-Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Randall Spangler <rspangler@chromium.org>
(cherry picked from commit bd81b3a7d3)
Change-Id: Iefdbfb3d10eb9aa385fb6dfc3bf0896f637cb64b
Reviewed-on: http://gerrit.chromium.org/gerrit/3582
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Tested-by: Randall Spangler <rspangler@chromium.org>
This is part 3 of the vboot wrapper API refactoring. It replaces the
function calls to utility.c functions with new API calls. (It also
fixes up some integer type mismatches in cryptolib that were causing
warnings on the H2C build; those had been fixed a while ago in H2C but
hadn't been propagated across.)
BUG=chromium-os:17006
TEST=make && make runtests
Change-Id: I771085dcdf79d9592de64f35e3b758111a80dd9f
Reviewed-on: http://gerrit.chromium.org/gerrit/3263
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Randall Spangler <rspangler@chromium.org>
This is part 2 of the wrapper API refactor. It adds stub
implementations for the host, and changes the host-side utilities to
use them. Firmware implementation is unchanged in this CL (other than
a few updates to macros).
BUG=chromium_os:16997
TEST=make && make runtests
Change-Id: I63989bd11de1f2239ddae256beaccd31bfb5acef
Reviewed-on: http://gerrit.chromium.org/gerrit/3256
Reviewed-by: Stefan Reinauer <reinauer@chromium.org>
Tested-by: Randall Spangler <rspangler@chromium.org>
BUG=chromium-os:16925
TEST=run "tpmc getvf" before stopping tcsd and observe that the error message no longer says "forgot to call TlclLibInit()"
Change-Id: I867c010c07286c0aa4cec49dda60524de1c2bec1
Reviewed-on: http://gerrit.chromium.org/gerrit/3147
Tested-by: Luigi Semenzato <semenzato@chromium.org>
Reviewed-by: Randall Spangler <rspangler@chromium.org>
R=reinauer@chromium.org
BUG=chrome-os-partner:2578
TEST=manual
crossystem vdat_timers
should show 'LFS=0,0 LF=number1,number2 LK=number3,number4'
where number1 < number2 < number3 < number4
crossystem vdat_lfdebug
run from a dev mode console, should show
'check=12,0 index=0x00 tpmver=(hex number) lowestver=(hex number)'
crossystem vdat_flags
run from a dev mode console, flags should be 0x04.
Review URL: http://codereview.chromium.org/6685068
Change-Id: Id7b958ae300d10cdcdc1b17a1bb17b7e5069166f
Change-Id: I8d52765227fd3355431bebc77dfbe0106c889eca
BUG=chrome-os-partner:2748
TEST=compiles; will be porting to H2C next
Review URL: http://codereview.chromium.org/6672068
Change-Id: I976c11c82c3d665a4feb88226e919f16c2440f60
BUG=chrome-os-partner:1657
TEST=manual - see below
make && make runtests
Then test verifying a test image in both dev mode (-b1, no key specified) and recovery mode (key specified)
build/utility/load_kernel_test -b1 ~/b/USB_images/0.11.224.0-alex/chromiumos_test_image.bin
build/utility/load_kernel_test ~/b/USB_images/0.11.224.0-alex/chromiumos_test_image.bin tests/devkeys/recovery_key.vbpubk
And make sure the firmware with this change actually boots to USB and SSD.
NOTE: u-boot-next needs to change to work with this change. will attempt a follow-up CL with that change
Review URL: http://codereview.chromium.org/6626045
Change-Id: I19f402904978581eb5ca990ffbdf2f762b48c217
BUG=12282
TEST=make H2C firmware and verify using crossystem utility
(set fwb_tries, reboot, verify that mainfw_act is B)
Review URL: http://codereview.chromium.org/6597018
TlclStubInit, TlclCloseDevice, and TlclOpenDevice were void functions but
should return error codes.
BUG=chromium-os:6695
TEST=RUNTESTS=1 make && emerge successfully
Review URL: http://codereview.chromium.org/5796005
Change-Id: I8ddbf8b1f080d98ff6ed42c4a675fbda5b17eef1
Check /usr/include/inttypes.h; PRIu64 is defined as "llu" or "lu" without leading "%" character.
Removing leading "%" character for compatibility.
BUG=None
TEST=Build successfully and run with u-boot and verify that outputs with PRIu64 are correct.
Review URL: http://codereview.chromium.org/5634003
Change-Id: Id5c3c5307b1c98625eb212dd11daa7a3833a9c18
While trying to debug/test some vbutil_kernel changes
(coming in a different CL) it was noticed that this utility
is not covered by tests, and the script which runs it to set
up further testing (tests/gen_fuzz_test_cases.sh) fails
because of the key format mismatch.
Some investigation has shown that this was left behind when
vboot_reference key storage format was changed.
To make gen_fuzz_test_cases.sh work again a new set of test
keys is required, the keys are generated by
tests/gen_test_keys.sh. This utility had to be changed to
generate the proper set of wrapped public and private keys.
Actually code in tests/gen_test_keys.shgenerate_keys() is
copied in pasted in many scripts in this tree, this has to
be refactored, but under a different CL.
Once the changes were made, two scripts were run:
./tests/gen_test_keys.sh
./gen_test_cases.sh
resulting in the new and updated keys generated.
firmware/stub/tpm_lite_stub.c was edited to fix compilation
warning issued when compiling with debugging enabled.
Change-Id: I26a45cbad00d21a29195f2a89b4df7d3559133fe
BUG=chromium-os:7178
TEST=described below
The following commands succeed:
vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
make
make runtests
./tests/gen_fuzz_test_cases.sh
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note that ./tests/gen_fuzz_test_cases.sh was failing
before this change.
The upcoming CL modifying vbutil_kernel will make sure
gen_fuzz_test_cases.sh is executed when tests are run and
will enhance it to cover vbutil_kernel testing.
Review URL: http://codereview.chromium.org/3423022
