Update for new Android Verified Boot (AVB).
This updates the build system for the new Android Verified Boot
codebase. As this is based on Brillo Verified Boot, this change replaces
the existing BVB support.
Android Verified Boot is enabled by the BOARD_AVB_ENABLE variable
BOARD_AVB_ENABLE := true
This will make the build system create vbmeta.img which will contain a
hash descriptor for boot.img, a hashtree descriptor for system.img, a
kernel-cmdline descriptor for setting up dm-verity for system.img and
append a hash-tree to system.img.
Additionally, the descriptors are left in boot.img and system.img so a
third party can create their own vbmeta.img file linking - using the
option --chain_partition - to these images. If this is not needed
footers can be erased using the 'avbtool erase_footer' command. It's
also harmless to just leave them in the images.
By default, the algorithm SHA256_RSA4096 is used with a test key from
the AVB source directory. This can be overriden by the
BOARD_AVB_ALGORITHM and BOARD_AVB_KEY_PATH variables to use e.g. a
4096-bit RSA key and SHA-512:
BOARD_AVB_ALGORITHM := SHA512_RSA4096
BOARD_AVB_KEY_PATH := /path/to/rsa_key_4096bits.pem
To prevent rollback attacks, the rollback index should be increased on a
regular basis. The rollback index can be set with the
BOARD_AVB_ROLLBACK_INDEX variable:
BOARD_AVB_ROLLBACK_INDEX := 5
If this is not set, the rollback index defaults to 0.
The variable BOARD_AVB_MAKE_VBMETA_IMAGE_ARGS can be used to specify
additional options passed to 'avbtool make_vbmeta_image'. Typical
options to be used here include '--prop', '--prop_from_file', and
'--chain_partition'.
The variable BOARD_AVBTOOL_BOOT_ADD_HASH_FOOTER_ARGS can be used to
specify additional options passed to 'avbtool add_hash_footer' for
boot.img. Typical options to be used here include '--hash_algorithm' and
'--salt'.
The variable BOARD_AVBTOOL_SYSTEM_ADD_HASHTREE_FOOTER_ARGS can be used
to specify additional options passed to 'avbtool add_hashtree_footer'
for systems.img. Typical options to be used here include
'--hash_algorithm', '--salt', and '--block_size'.
BUG=31264226
TEST=Manually tested on edison-eng by inspecting {boot, system,
vbmeta}.img in out/ directory as well as their counterparts in
the IMAGES/ directory of edision-target_files-eng.zeuthen.zip
Merged-In: Ic9a61cfc65c148b12996e57f04da5432eef6b982
Change-Id: I97042655bca15e7eac899f12c5bada2f6184d307
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index 3f3b011..564cd17 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -384,6 +384,16 @@
print "%-25s = (%s) %s" % (k, type(v).__name__, v)
+def AppendAVBSigningArgs(cmd):
+ """Append signing arguments for avbtool."""
+ keypath = OPTIONS.info_dict.get("board_avb_key_path", None)
+ algorithm = OPTIONS.info_dict.get("board_avb_algorithm", None)
+ if not keypath or not algorithm:
+ algorithm = "SHA256_RSA4096"
+ keypath = "external/avb/test/data/testkey_rsa4096.pem"
+ cmd.extend(["--key", keypath, "--algorithm", algorithm])
+
+
def _BuildBootableImage(sourcedir, fs_config_file, info_dict=None,
has_ramdisk=False):
"""Build a bootable image from the specified sourcedir.
@@ -503,111 +513,20 @@
img_unsigned.close()
img_keyblock.close()
- img.seek(os.SEEK_SET, 0)
- data = img.read()
-
- if has_ramdisk:
- ramdisk_img.close()
- img.close()
-
- return data
-
-
-def _BuildBvbBootableImage(sourcedir, fs_config_file, system_img_path,
- info_dict=None, has_ramdisk=False):
- """Build a bootable image compatible with Brillo Verified Boot from the
- specified sourcedir.
-
- Take a kernel, cmdline, system image path, and optionally a ramdisk
- directory from the input (in 'sourcedir'), and turn them into a boot
- image. Return the image data, or None if sourcedir does not appear
- to contains files for building the requested image.
- """
-
- def make_ramdisk():
- ramdisk_img = tempfile.NamedTemporaryFile()
-
- if os.access(fs_config_file, os.F_OK):
- cmd = ["mkbootfs", "-f", fs_config_file,
- os.path.join(sourcedir, "RAMDISK")]
- else:
- cmd = ["mkbootfs", os.path.join(sourcedir, "RAMDISK")]
- p1 = Run(cmd, stdout=subprocess.PIPE)
- p2 = Run(["minigzip"], stdin=p1.stdout, stdout=ramdisk_img.file.fileno())
-
- p2.wait()
- p1.wait()
- assert p1.returncode == 0, "mkbootfs of %s ramdisk failed" % (sourcedir,)
- assert p2.returncode == 0, "minigzip of %s ramdisk failed" % (sourcedir,)
-
- return ramdisk_img
-
- if not os.access(os.path.join(sourcedir, "kernel"), os.F_OK):
- return None
-
- if has_ramdisk and not os.access(os.path.join(sourcedir, "RAMDISK"), os.F_OK):
- return None
-
- if info_dict is None:
- info_dict = OPTIONS.info_dict
-
- img = tempfile.NamedTemporaryFile()
-
- if has_ramdisk:
- ramdisk_img = make_ramdisk()
-
- # use BVBTOOL from environ, or "bvbtool" if empty or not set
- bvbtool = os.getenv('BVBTOOL') or "bvbtool"
-
- # First, create boot.img.
- cmd = [bvbtool, "make_boot_image"]
-
- fn = os.path.join(sourcedir, "cmdline")
- if os.access(fn, os.F_OK):
- cmd.append("--kernel_cmdline")
- cmd.append(open(fn).read().rstrip("\n"))
-
- cmd.extend(["--kernel", os.path.join(sourcedir, "kernel")])
-
- if has_ramdisk:
- cmd.extend(["--initrd", ramdisk_img.name])
-
- cmd.extend(["--rootfs_with_hashes", system_img_path])
-
- args = info_dict.get("board_bvb_make_boot_image_args", None)
- if args and args.strip():
- cmd.extend(shlex.split(args))
-
- rollback_index = info_dict.get("board_bvb_rollback_index", None)
- if rollback_index and rollback_index.strip():
- cmd.extend(["--rollback_index", rollback_index.strip()])
-
- cmd.extend(["--output", img.name])
-
- p = Run(cmd, stdout=subprocess.PIPE)
- p.communicate()
- assert p.returncode == 0, "bvbtool make_boot_image of %s image failed" % (
- os.path.basename(sourcedir),)
-
- # Then, sign boot.img.
- cmd = [bvbtool, "sign_boot_image", "--image", img.name]
-
- algorithm = info_dict.get("board_bvb_algorithm", None)
- key_path = info_dict.get("board_bvb_key_path", None)
- if algorithm and algorithm.strip() and key_path and key_path.strip():
- cmd.extend(["--algorithm", algorithm, "--key", key_path])
- else:
- cmd.extend(["--algorithm", "SHA256_RSA4096"])
- cmd.extend(["--key", "external/bvb/test/testkey_rsa4096.pem"])
-
- args = info_dict.get("board_bvb_sign_boot_image_args", None)
- if args and args.strip():
- cmd.extend(shlex.split(args))
-
- p = Run(cmd, stdout=subprocess.PIPE)
- p.communicate()
- assert p.returncode == 0, "bvbtool sign_boot_image of %s image failed" % (
- os.path.basename(sourcedir),)
+ # AVB: if enabled, calculate and add hash to boot.img.
+ if OPTIONS.info_dict.get("board_avb_enable", None) == "true":
+ avbtool = os.getenv('AVBTOOL') or "avbtool"
+ part_size = OPTIONS.info_dict.get("boot_size", None)
+ cmd = [avbtool, "add_hash_footer", "--image", img.name,
+ "--partition_size", str(part_size), "--partition_name", "boot"]
+ AppendAVBSigningArgs(cmd)
+ args = OPTIONS.info_dict.get("board_avb_boot_add_hash_footer_args", None)
+ if args and args.strip():
+ cmd.extend(shlex.split(args))
+ p = Run(cmd, stdout=subprocess.PIPE)
+ p.communicate()
+ assert p.returncode == 0, "avbtool add_hash_footer of %s failed" % (
+ os.path.basename(OPTIONS.input_tmp))
img.seek(os.SEEK_SET, 0)
data = img.read()
@@ -650,14 +569,9 @@
info_dict.get("recovery_as_boot") == "true")
fs_config = "META/" + tree_subdir.lower() + "_filesystem_config.txt"
- if info_dict.get("board_bvb_enable", None) == "true":
- data = _BuildBvbBootableImage(os.path.join(unpack_dir, tree_subdir),
- os.path.join(unpack_dir, fs_config),
- system_img_path, info_dict, has_ramdisk)
- else:
- data = _BuildBootableImage(os.path.join(unpack_dir, tree_subdir),
- os.path.join(unpack_dir, fs_config),
- info_dict, has_ramdisk)
+ data = _BuildBootableImage(os.path.join(unpack_dir, tree_subdir),
+ os.path.join(unpack_dir, fs_config),
+ info_dict, has_ramdisk)
if data:
return File(name, data)
return None