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: Mounting dm-verity set up from system.img now works.

Merged-In: I4c5de1004c1059f8c582e76b3b8517d427aa1a87

Change-Id: I945a5f1f6782791736cd319f216cfa6b448fb04d

core/Makefile

@@ -873,6 +873,10 @@ $(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)),\
@@ -1180,13 +1184,6 @@ 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)

tools/releasetools/add_img_to_target_files.py

@@ -96,23 +96,6 @@ 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

tools/releasetools/build_image.py

@@ -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:
@@ -497,6 +555,17 @@ 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:
@@ -537,7 +606,9 @@ 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)
@@ -559,6 +630,9 @@ def ImagePropFromGlobalDict(glob_dict, mount_point):
     copy_prop("system_squashfs_compressor_opt", "squashfs_compressor_opt")
     copy_prop("system_squashfs_disable_4k_align", "squashfs_disable_4k_align")
     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")
@@ -577,12 +651,15 @@ def ImagePropFromGlobalDict(glob_dict, mount_point):
     copy_prop("vendor_squashfs_compressor_opt", "squashfs_compressor_opt")
     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