Skip to content

Commit

Permalink
Move enable/disable-verity code from avbctl to libavb_user.
Browse files Browse the repository at this point in the history 
Also build a libavb_user library and make avbctl link with it. Also
add a function to get whether verity is currrently enabled and expose
this through a new get-verity sub-command in avbctl. Make avbctl a bit
smarter and tell the user if verity is already enabled/disabled when
trying to enable/disable it. Also remind the user to reboot if we're
changing the state.

With this change it's possible to make adbd link with libavb_user for
implementing 'adb {enable,disable}-verity' command.

Also stop linking avbctl with the boot_control HAL and just access the
ro.boot.slot or ro.boot.slot_suffix properties (aka "androidboot.slot"
or "androidboot.slot_suffix" on the kernel cmdline). This way
external/avb should be usable on N without manually having to patch in
the O->N boot_control changes.

Complete AvbOps in libavb_user so it can be used with avb_slot_verify()
in user space. Also add more documentation explaining what this particular
AvbOps implementation is intended to do.

Bug: 34124301
Test: All unit tests pass.
Test: Manually tested on UEFI-based bootloader.
Change-Id: I0b5080ff102c29f2c4c0e92a9737590d450967a9
  • Loading branch information
@davidz25
davidz25 committed Apr 17, 2017
1 parent ee46039 commit 3a58015
Show file tree
Hide file tree
Showing 7 changed files with 470 additions and 198 deletions.
99 changes: 53 additions & 46 deletions Android.mk
View file
Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,25 @@ avb_common_ldflags := \
-Wl,--gc-sections \
-rdynamic

# The sources that make up libavb (excluding sysdeps).
libavb_sources := \
libavb/avb_chain_partition_descriptor.c \
libavb/avb_crc32.c \
libavb/avb_crypto.c \
libavb/avb_descriptor.c \
libavb/avb_footer.c \
libavb/avb_hash_descriptor.c \
libavb/avb_hashtree_descriptor.c \
libavb/avb_kernel_cmdline_descriptor.c \
libavb/avb_property_descriptor.c \
libavb/avb_rsa.c \
libavb/avb_sha256.c \
libavb/avb_sha512.c \
libavb/avb_slot_verify.c \
libavb/avb_util.c \
libavb/avb_vbmeta_image.c \
libavb/avb_version.c

include $(CLEAR_VARS)
LOCAL_SRC_FILES := avbtool
LOCAL_MODULE_CLASS := EXECUTABLES
Expand All @@ -52,7 +71,8 @@ LOCAL_IS_HOST_MODULE := true
LOCAL_MODULE := avbtool
include $(BUILD_PREBUILT)

# Build libavb for the target (for e.g. fs_mgr usage).
# Build libavb for the target - this is a static library that depends
# on only libc and doesn't drag in any other dependencies.
include $(CLEAR_VARS)
LOCAL_MODULE := libavb
LOCAL_MODULE_HOST_OS := linux
Expand All @@ -61,23 +81,30 @@ LOCAL_CLANG := true
LOCAL_CFLAGS := $(avb_common_cflags) -DAVB_ENABLE_DEBUG -DAVB_COMPILATION
LOCAL_LDFLAGS := $(avb_common_ldflags)
LOCAL_SRC_FILES := \
libavb/avb_chain_partition_descriptor.c \
libavb/avb_crc32.c \
libavb/avb_crypto.c \
libavb/avb_descriptor.c \
libavb/avb_footer.c \
libavb/avb_hash_descriptor.c \
libavb/avb_hashtree_descriptor.c \
libavb/avb_kernel_cmdline_descriptor.c \
libavb/avb_property_descriptor.c \
libavb/avb_rsa.c \
libavb/avb_sha256.c \
libavb/avb_sha512.c \
libavb/avb_slot_verify.c \
$(libavb_sources) \
libavb/avb_sysdeps_posix.c
include $(BUILD_STATIC_LIBRARY)

# Build libavb_user for the target - in addition to libavb, it
# includes libavb_ab, libavb_user and also depends on libbase and
# libfs_mgr.
include $(CLEAR_VARS)
LOCAL_MODULE := libavb_user
LOCAL_MODULE_HOST_OS := linux
LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)
LOCAL_CLANG := true
LOCAL_CFLAGS := $(avb_common_cflags) -DAVB_ENABLE_DEBUG -DAVB_COMPILATION
LOCAL_LDFLAGS := $(avb_common_ldflags)
LOCAL_SHARED_LIBRARIES := \
libbase
LOCAL_STATIC_LIBRARIES := \
libfs_mgr
LOCAL_SRC_FILES := \
$(libavb_sources) \
libavb/avb_sysdeps_posix.c \
libavb/avb_util.c \
libavb/avb_vbmeta_image.c \
libavb/avb_version.c
libavb_ab/avb_ab_flow.c \
libavb_user/avb_ops_user.c \
libavb_user/avb_user_verity.c
include $(BUILD_STATIC_LIBRARY)

# Build avbctl for the target.
Expand All @@ -91,18 +118,11 @@ LOCAL_CFLAGS := $(avb_common_cflags) -DAVB_COMPILATION -DAVB_ENABLE_DEBUG
LOCAL_CPPFLAGS := $(avb_common_cppflags)
LOCAL_LDFLAGS := $(avb_common_ldflags)
LOCAL_STATIC_LIBRARIES := \
libavb \
libavb_user \
libfs_mgr
LOCAL_SHARED_LIBRARIES := \
libbase \
libhidlbase \
libhidltransport \
libhwbinder \
libutils \
[email protected]
libbase
LOCAL_SRC_FILES := \
libavb_ab/avb_ab_flow.c \
libavb_user/avb_ops_user.c \
tools/avbctl/avbctl.cc
include $(BUILD_EXECUTABLE)

Expand All @@ -116,21 +136,7 @@ LOCAL_CLANG := true
LOCAL_CFLAGS := $(avb_common_cflags) -fno-stack-protector -DAVB_ENABLE_DEBUG -DAVB_COMPILATION
LOCAL_LDFLAGS := $(avb_common_ldflags)
LOCAL_SRC_FILES := \
libavb/avb_chain_partition_descriptor.c \
libavb/avb_crc32.c \
libavb/avb_crypto.c \
libavb/avb_descriptor.c \
libavb/avb_footer.c \
libavb/avb_hash_descriptor.c \
libavb/avb_hashtree_descriptor.c \
libavb/avb_kernel_cmdline_descriptor.c \
libavb/avb_property_descriptor.c \
libavb/avb_rsa.c \
libavb/avb_sha256.c \
libavb/avb_sha512.c \
libavb/avb_slot_verify.c \
libavb/avb_util.c \
libavb/avb_vbmeta_image.c \
$(libavb_sources) \
libavb/avb_version.c
include $(BUILD_HOST_STATIC_LIBRARY)

Expand Down Expand Up @@ -220,16 +226,17 @@ include $(BUILD_HOST_STATIC_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := bootctrl.avb
LOCAL_MODULE_RELATIVE_PATH := hw
LOCAL_REQUIRED_MODULES := libavb
LOCAL_SRC_FILES := \
libavb_ab/avb_ab_flow.c \
libavb_user/avb_ops_user.c \
boot_control/boot_control_avb.c
LOCAL_CLANG := true
LOCAL_CFLAGS := $(avb_common_cflags) -DAVB_COMPILATION
LOCAL_LDFLAGS := $(avb_common_ldflags)
LOCAL_SHARED_LIBRARIES := libbase libcutils
LOCAL_STATIC_LIBRARIES := libfs_mgr libavb
LOCAL_SHARED_LIBRARIES := \
libbase \
libcutils
LOCAL_STATIC_LIBRARIES := \
libavb_user \
libfs_mgr
LOCAL_POST_INSTALL_CMD := \
$(hide) mkdir -p $(TARGET_OUT_SHARED_LIBRARIES)/hw && \
ln -sf bootctrl.avb.so $(TARGET_OUT_SHARED_LIBRARIES)/hw/bootctrl.default.so
Expand Down
50 changes: 50 additions & 0 deletions libavb_user/avb_ops_user.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -221,6 +221,51 @@ static AvbIOResult write_to_partition(AvbOps* ops,
return ret;
}

static AvbIOResult validate_vbmeta_public_key(
AvbOps* ops,
const uint8_t* public_key_data,
size_t public_key_length,
const uint8_t* public_key_metadata,
size_t public_key_metadata_length,
bool* out_is_trusted) {
if (out_is_trusted != NULL) {
*out_is_trusted = true;
}
return AVB_IO_RESULT_OK;
}

static AvbIOResult read_rollback_index(AvbOps* ops,
size_t rollback_index_location,
uint64_t* out_rollback_index) {
if (out_rollback_index != NULL) {
*out_rollback_index = 0;
}
return AVB_IO_RESULT_OK;
}

static AvbIOResult write_rollback_index(AvbOps* ops,
size_t rollback_index_location,
uint64_t rollback_index) {
return AVB_IO_RESULT_OK;
}

static AvbIOResult read_is_device_unlocked(AvbOps* ops, bool* out_is_unlocked) {
if (out_is_unlocked != NULL) {
*out_is_unlocked = true;
}
return AVB_IO_RESULT_OK;
}

static AvbIOResult get_unique_guid_for_partition(AvbOps* ops,
const char* partition,
char* guid_buf,
size_t guid_buf_size) {
if (guid_buf != NULL && guid_buf_size > 0) {
guid_buf[0] = '\0';
}
return AVB_IO_RESULT_OK;
}

AvbOps* avb_ops_user_new(void) {
AvbOps* ops;

Expand All @@ -240,6 +285,11 @@ AvbOps* avb_ops_user_new(void) {

ops->read_from_partition = read_from_partition;
ops->write_to_partition = write_to_partition;
ops->validate_vbmeta_public_key = validate_vbmeta_public_key;
ops->read_rollback_index = read_rollback_index;
ops->write_rollback_index = write_rollback_index;
ops->read_is_device_unlocked = read_is_device_unlocked;
ops->get_unique_guid_for_partition = get_unique_guid_for_partition;
ops->ab_ops->read_ab_metadata = avb_ab_data_read;
ops->ab_ops->write_ab_metadata = avb_ab_data_write;

Expand Down
25 changes: 23 additions & 2 deletions libavb_user/avb_ops_user.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -31,8 +31,29 @@
extern "C" {
#endif

/* Allocates an AvbOps instance suitable for use in userspace on the
* device. Returns NULL on OOM.
/* Allocates an AvbOps instance suitable for use in Android userspace
* on the device. Returns NULL on OOM.
*
* The returned AvbOps has the following characteristics:
*
* - The read_from_partition() and write_to_partition() operations are
* implemented, however for these operations to work the fstab file
* on the device must have a /misc entry using a by-name device file
* scheme and the containing by-name/ subdirectory must have files
* for other partitions.
*
* - The remaining operations are implemented and never fails and
* return the following values:
* - validate_vbmeta_public_key(): always returns |true|.
* - read_rollback_index(): returns 0 for any roolback index.
* - write_rollback_index(): no-op.
* - read_is_device_unlocked(): always returns |true|.
* - get_unique_guid_for_partition(): always returns the empty string.
*
* - The |ab_ops| member will point to a valid AvbABOps instance
* implemented via libavb_ab/. This should only be used if the AVB
* A/B stack is used on the device. This is what is used in
* bootctrl.avb boot control implementation.
*
* Free with avb_ops_user_free().
*/
Expand Down
Loading

0 comments on commit 3a58015

Please sign in to comment.