Add support for verity builds to the build system.
Change-Id: I3ef908d8d52ec88de453b161bbc3f198517a72f1
diff --git a/tools/releasetools/build_image.py b/tools/releasetools/build_image.py
index f8f2ada..964f277 100755
--- a/tools/releasetools/build_image.py
+++ b/tools/releasetools/build_image.py
@@ -24,6 +24,8 @@
import os.path
import subprocess
import sys
+import commands
+import shutil
def RunCommand(cmd):
""" Echo and run the given command
@@ -38,6 +40,167 @@
p.communicate()
return p.returncode
+def GetVerityTreeSize(partition_size):
+ cmd = "system/extras/verity/build_verity_tree.py -s %d"
+ cmd %= partition_size
+ status, output = commands.getstatusoutput(cmd)
+ if status:
+ print output
+ return False, 0
+ return True, int(output)
+
+def GetVerityMetadataSize(partition_size):
+ cmd = "system/extras/verity/build_verity_metadata.py -s %d"
+ cmd %= partition_size
+ status, output = commands.getstatusoutput(cmd)
+ if status:
+ print output
+ return False, 0
+ return True, int(output)
+
+def AdjustPartitionSizeForVerity(partition_size):
+ """Modifies the provided partition size to account for the verity metadata.
+
+ This information is used to size the created image appropriately.
+ Args:
+ partition_size: the size of the partition to be verified.
+ Returns:
+ The size of the partition adjusted for verity metadata.
+ """
+ success, verity_tree_size = GetVerityTreeSize(partition_size)
+ if not success:
+ return 0;
+ success, verity_metadata_size = GetVerityMetadataSize(partition_size)
+ if not success:
+ return 0
+ return partition_size - verity_tree_size - verity_metadata_size
+
+def BuildVerityTree(unsparse_image_path, verity_image_path, partition_size, prop_dict):
+ cmd = ("system/extras/verity/build_verity_tree.py %s %s %d" %
+ (unsparse_image_path, verity_image_path, partition_size))
+ print cmd
+ status, output = commands.getstatusoutput(cmd)
+ if status:
+ print "Could not build verity tree! Error: %s" % output
+ return False
+ root, salt = output.split()
+ prop_dict["verity_root_hash"] = root
+ prop_dict["verity_salt"] = salt
+ return True
+
+def BuildVerityMetadata(image_size, verity_metadata_path, root_hash, salt,
+ block_device, signer_path, key):
+ cmd = ("system/extras/verity/build_verity_metadata.py %s %s %s %s %s %s %s" %
+ (image_size,
+ verity_metadata_path,
+ root_hash,
+ salt,
+ block_device,
+ signer_path,
+ key))
+ print cmd
+ status, output = commands.getstatusoutput(cmd)
+ if status:
+ print "Could not build verity metadata! Error: %s" % output
+ return False
+ return True
+
+def Append2Simg(sparse_image_path, unsparse_image_path, error_message):
+ """Appends the unsparse image to the given sparse image.
+
+ Args:
+ sparse_image_path: the path to the (sparse) image
+ unsparse_image_path: the path to the (unsparse) image
+ Returns:
+ True on success, False on failure.
+ """
+ cmd = "append2simg %s %s"
+ cmd %= (sparse_image_path, unsparse_image_path)
+ print cmd
+ status, output = commands.getstatusoutput(cmd)
+ if status:
+ print "%s: %s" % (error_message, output)
+ return False
+ return True
+
+def BuildVerifiedImage(data_image_path, verity_image_path, verity_metadata_path):
+ if not Append2Simg(data_image_path, verity_metadata_path, "Could not append verity metadata!"):
+ return False
+ if not Append2Simg(data_image_path, verity_image_path, "Could not append verity tree!"):
+ return False
+ return True
+
+def UnsparseImage(sparse_image_path):
+ img_dir = os.path.dirname(sparse_image_path)
+ unsparse_image_path = "unsparse_" + os.path.basename(sparse_image_path)
+ unsparse_image_path = os.path.join(img_dir, unsparse_image_path)
+ if os.path.exists(unsparse_image_path):
+ return True, unsparse_image_path
+ inflate_command = ["simg2img", sparse_image_path, unsparse_image_path]
+ exit_code = RunCommand(inflate_command)
+ if exit_code != 0:
+ os.remove(unsparse_image_path)
+ return False, None
+ return True, unsparse_image_path
+
+def MakeVerityEnabledImage(out_file, prop_dict):
+ """Creates an image that is verifiable using dm-verity.
+
+ Args:
+ out_file: the location to write the verifiable image at
+ prop_dict: a dictionary of properties required for image creation and verification
+ Returns:
+ True on success, False otherwise.
+ """
+ # get properties
+ image_size = prop_dict["partition_size"]
+ part_size = int(prop_dict["original_partition_size"])
+ block_dev = prop_dict["verity_block_device"]
+ signer_key = prop_dict["verity_key"]
+ signer_path = prop_dict["verity_signer_cmd"]
+
+ # make a tempdir
+ tempdir_name = os.path.join(os.path.dirname(out_file), "verity_images")
+ if os.path.exists(tempdir_name):
+ shutil.rmtree(tempdir_name)
+ os.mkdir(tempdir_name)
+
+ # get partial image paths
+ verity_image_path = os.path.join(tempdir_name, "verity.img")
+ verity_metadata_path = os.path.join(tempdir_name, "verity_metadata.img")
+ success, unsparse_image_path = UnsparseImage(out_file)
+ if not success:
+ shutil.rmtree(tempdir_name)
+ return False
+
+ # build the verity tree and get the root hash and salt
+ if not BuildVerityTree(unsparse_image_path, verity_image_path, part_size, prop_dict):
+ shutil.rmtree(tempdir_name)
+ return False
+
+ # build the metadata blocks
+ root_hash = prop_dict["verity_root_hash"]
+ salt = prop_dict["verity_salt"]
+ if not BuildVerityMetadata(image_size,
+ verity_metadata_path,
+ root_hash,
+ salt,
+ block_dev,
+ signer_path,
+ signer_key):
+ shutil.rmtree(tempdir_name)
+ return False
+
+ # build the full verified image
+ if not BuildVerifiedImage(out_file,
+ verity_image_path,
+ verity_metadata_path):
+ shutil.rmtree(tempdir_name)
+ return False
+
+ shutil.rmtree(tempdir_name)
+ return True
+
def BuildImage(in_dir, prop_dict, out_file):
"""Build an image to out_file from in_dir with property prop_dict.
@@ -52,6 +215,16 @@
build_command = []
fs_type = prop_dict.get("fs_type", "")
run_fsck = False
+
+ # adjust the partition size to make room for the hashes if this is to be verified
+ if prop_dict.get("verity") == "true":
+ partition_size = int(prop_dict.get("partition_size"))
+ adjusted_size = AdjustPartitionSizeForVerity(partition_size)
+ if not adjusted_size:
+ return False
+ prop_dict["partition_size"] = str(adjusted_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:
@@ -77,14 +250,14 @@
if exit_code != 0:
return False
+ # create the verified image if this is to be verified
+ if prop_dict.get("verity") == "true":
+ if not MakeVerityEnabledImage(out_file, prop_dict):
+ return False
+
if run_fsck and prop_dict.get("skip_fsck") != "true":
- # Inflate the sparse image
- unsparse_image = os.path.join(
- os.path.dirname(out_file), "unsparse_" + os.path.basename(out_file))
- inflate_command = ["simg2img", out_file, unsparse_image]
- exit_code = RunCommand(inflate_command)
- if exit_code != 0:
- os.remove(unsparse_image)
+ success, unsparse_image_path = UnsparseImage(out_file)
+ if not success:
return False
# Run e2fsck on the inflated image file
@@ -114,6 +287,10 @@
"mkyaffs2_extra_flags",
"selinux_fc",
"skip_fsck",
+ "verity",
+ "verity_block_device",
+ "verity_key",
+ "verity_signer_cmd"
)
for p in common_props:
copy_prop(p, p)