Make room for AVB hashtree and metadata.

While the system.img images currently built with AVB support verify
correctly, mounting the filesystem content fails. This is because
'avbtool add_hashtree_footer' used to claim some of the unused /
DONT_CARE space for stashing the verity tables and this resulting in the
mapped device ending up being smaller causing the mount failure.

Fix this by leaving enough room for AVB hashtree and metadata before
building the image. This is achieved by moving the AVB hashtree support
into build_image.py and using a just added '--calc_max_image_size'
option to 'avbtool add_hashtree_footer' to figure out how much space to
leave out.

This depends on https://android-review.googlesource.com/#/c/281821/

Bug: 31264226
Test: aosp_x86_64-eng 'm' and 'm dist' successful.
Change-Id: I4c5de1004c1059f8c582e76b3b8517d427aa1a87
This commit is contained in:
David Zeuthen 2016-10-03 12:00:35 -04:00
parent 906d068436
commit 52872baa78
3 changed files with 83 additions and 26 deletions

View file

@ -882,6 +882,10 @@ $(if $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_SUPPORTS_VBOOT),$(hide) echo "vboot_
$(if $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_SUPPORTS_VBOOT),$(hide) echo "vboot_subkey=$(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_VBOOT_SIGNING_SUBKEY)" >> $(1))
$(if $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_SUPPORTS_VBOOT),$(hide) echo "futility=$(FUTILITY)" >> $(1))
$(if $(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_SUPPORTS_VBOOT),$(hide) echo "vboot_signer_cmd=$(VBOOT_SIGNER)" >> $(1))
$(if $(BOARD_AVB_ENABLE),$(hide) echo "avb_signing_args=$(INTERNAL_AVB_SIGNING_ARGS)" >> $(1))
$(if $(BOARD_AVB_ENABLE),$(hide) echo "avb_avbtool=$(AVBTOOL)" >> $(1))
$(if $(BOARD_AVB_ENABLE),$(hide) echo "system_avb_enable=$(BOARD_AVB_ENABLE)" >> $(1))
$(if $(BOARD_AVB_ENABLE),$(hide) echo "system_avb_add_hashtree_footer_args=$(BOARD_AVB_SYSTEM_ADD_HASHTREE_FOOTER_ARGS)" >> $(1))
$(if $(filter true,$(BOARD_USES_RECOVERY_AS_BOOT)),\
$(hide) echo "recovery_as_boot=true" >> $(1))
$(if $(filter true,$(BOARD_BUILD_SYSTEM_ROOT_IMAGE)),\
@ -1194,13 +1198,6 @@ define build-systemimage-target
fi; \
mkdir -p $(DIST_DIR); cp $(INSTALLED_FILES_FILE) $(DIST_DIR)/installed-files-rescued.txt; \
exit 1 )
$(if $(BOARD_AVB_ENABLE), \
$(hide) $(AVBTOOL) add_hashtree_footer \
--image $(1) \
--partition_size $(BOARD_SYSTEMIMAGE_PARTITION_SIZE) \
--partition_name system \
$(INTERNAL_AVB_SIGNING_ARGS) \
$(BOARD_AVB_SYSTEM_ADD_HASHTREE_FOOTER_ARGS))
endef
$(BUILT_SYSTEMIMAGE): $(FULL_SYSTEMIMAGE_DEPS) $(INSTALLED_FILES_FILE) $(BUILD_IMAGE_SRCS)

View file

@ -110,23 +110,6 @@ def AddSystem(output_zip, prefix="IMAGES/", recovery_img=None, boot_img=None):
imgname = BuildSystem(OPTIONS.input_tmp, OPTIONS.info_dict,
block_list=block_list)
# AVB: if enabled, calculate and add dm-verity integrity hashes and
# metadata to system.img.
if OPTIONS.info_dict.get("board_avb_enable", None) == "true":
avbtool = os.getenv('AVBTOOL') or "avbtool"
part_size = OPTIONS.info_dict.get("system_size", None)
cmd = [avbtool, "add_hashtree_footer", "--image", imgname,
"--partition_size", str(part_size), "--partition_name", "system"]
common.AppendAVBSigningArgs(cmd)
args = OPTIONS.info_dict.get("board_avb_system_add_hashtree_footer_args",
None)
if args and args.strip():
cmd.extend(shlex.split(args))
p = common.Run(cmd, stdout=subprocess.PIPE)
p.communicate()
assert p.returncode == 0, "avbtool add_hashtree_footer of %s failed" % (
os.path.basename(OPTIONS.input_tmp))
common.ZipWrite(output_zip, imgname, prefix + "system.img")
common.ZipWrite(output_zip, block_list, prefix + "system.map")
return imgname

View file

@ -27,6 +27,7 @@ import subprocess
import sys
import commands
import common
import shlex
import shutil
import sparse_img
import tempfile
@ -102,6 +103,51 @@ def ZeroPadSimg(image_file, pad_size):
simg = sparse_img.SparseImage(image_file, mode="r+b", build_map=False)
simg.AppendFillChunk(0, blocks)
def AVBCalcMaxImageSize(avbtool, partition_size, additional_args):
"""Calculates max image size for a given partition size.
Args:
avbtool: String with path to avbtool.
partition_size: The size of the partition in question.
additional_args: Additional arguments to pass to 'avbtool
add_hashtree_image'.
Returns:
The maximum image size or 0 if an error occurred.
"""
cmdline = "%s add_hashtree_footer " % avbtool
cmdline += "--partition_size %d " % partition_size
cmdline += "--calc_max_image_size "
cmdline += additional_args
(output, exit_code) = RunCommand(shlex.split(cmdline))
if exit_code != 0:
return 0
else:
return int(output)
def AVBAddHashtree(image_path, avbtool, partition_size, partition_name,
signing_args, additional_args):
"""Adds dm-verity hashtree and AVB metadata to an image.
Args:
image_path: Path to image to modify.
avbtool: String with path to avbtool.
partition_size: The size of the partition in question.
partition_name: The name of the partition - will be embedded in metadata.
signing_args: Arguments for signing the image.
additional_args: Additional arguments to pass to 'avbtool
add_hashtree_image'.
Returns:
True if the operation succeeded.
"""
cmdline = "%s add_hashtree_footer " % avbtool
cmdline += "--partition_size %d " % partition_size
cmdline += "--partition_name %s " % partition_name
cmdline += "--image %s " % image_path
cmdline += signing_args + " "
cmdline += additional_args
(_, exit_code) = RunCommand(shlex.split(cmdline))
return exit_code == 0
def AdjustPartitionSizeForVerity(partition_size, fec_supported):
"""Modifies the provided partition size to account for the verity metadata.
@ -375,6 +421,18 @@ def BuildImage(in_dir, prop_dict, out_file, target_out=None):
prop_dict["original_partition_size"] = str(partition_size)
prop_dict["verity_size"] = str(verity_size)
# Adjust partition size for AVB.
if prop_dict.get("avb_enable") == "true":
avbtool = prop_dict.get("avb_avbtool")
partition_size = int(prop_dict.get("partition_size"))
additional_args = prop_dict["avb_add_hashtree_footer_args"]
max_image_size = AVBCalcMaxImageSize(avbtool, partition_size,
additional_args)
if max_image_size == 0:
return False
prop_dict["partition_size"] = str(max_image_size)
prop_dict["original_partition_size"] = str(partition_size)
if fs_type.startswith("ext"):
build_command = ["mkuserimg.sh"]
if "extfs_sparse_flag" in prop_dict:
@ -499,6 +557,17 @@ def BuildImage(in_dir, prop_dict, out_file, target_out=None):
if not MakeVerityEnabledImage(out_file, verity_fec_supported, prop_dict):
return False
# Add AVB hashtree and metadata.
if "avb_enable" in prop_dict:
avbtool = prop_dict.get("avb_avbtool")
original_partition_size = int(prop_dict.get("original_partition_size"))
partition_name = prop_dict["partition_name"]
signing_args = prop_dict["avb_signing_args"]
additional_args = prop_dict["avb_add_hashtree_footer_args"]
if not AVBAddHashtree(out_file, avbtool, original_partition_size,
partition_name, signing_args, additional_args):
return False
if run_fsck and prop_dict.get("skip_fsck") != "true":
success, unsparse_image = UnsparseImage(out_file, replace=False)
if not success:
@ -539,7 +608,9 @@ def ImagePropFromGlobalDict(glob_dict, mount_point):
"verity",
"verity_key",
"verity_signer_cmd",
"verity_fec"
"verity_fec",
"avb_signing_args",
"avb_avbtool"
)
for p in common_props:
copy_prop(p, p)
@ -575,6 +646,9 @@ def ImagePropFromGlobalDict(glob_dict, mount_point):
copy_prop("system_squashfs_compressor_opt", "squashfs_compressor_opt")
copy_prop("system_squashfs_block_size", "squashfs_block_size")
copy_prop("system_base_fs_file", "base_fs_file")
copy_prop("system_avb_enable", "avb_enable")
copy_prop("system_avb_add_hashtree_footer_args",
"avb_add_hashtree_footer_args")
elif mount_point == "data":
# Copy the generic fs type first, override with specific one if available.
copy_prop("fs_type", "fs_type")
@ -594,12 +668,15 @@ def ImagePropFromGlobalDict(glob_dict, mount_point):
copy_prop("vendor_squashfs_block_size", "squashfs_block_size")
copy_prop("vendor_squashfs_disable_4k_align", "squashfs_disable_4k_align")
copy_prop("vendor_base_fs_file", "base_fs_file")
copy_prop("vendor_avb_enable", "avb_enable")
copy_prop("vendor_avb_add_hashtree_footer_args",
"avb_add_hashtree_footer_args")
elif mount_point == "oem":
copy_prop("fs_type", "fs_type")
copy_prop("oem_size", "partition_size")
copy_prop("oem_journal_size", "journal_size")
copy_prop("has_ext4_reserved_blocks", "has_ext4_reserved_blocks")
d["partition_name"] = mount_point
return d