filesystem/vbmeta.go - platform/build/soong - Git at Google

 // Copyright (C) 2021 The Android Open Source Project
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 package filesystem

 import (
 	"fmt"
 	"strconv"

 	"github.com/google/blueprint"
 	"github.com/google/blueprint/proptools"

 	"android/soong/android"
 )

 func init() {
 	android.RegisterModuleType("vbmeta", vbmetaFactory)
 }

 type vbmeta struct {
 	android.ModuleBase

 	properties vbmetaProperties

 	output     android.OutputPath
 	installDir android.InstallPath
 }

 type vbmetaProperties struct {
 	// Name of the partition stored in vbmeta desc. Defaults to the name of this module.
 	Partition_name *string

 	// Set the name of the output. Defaults to <module_name>.img.
 	Stem *string

 	// Path to the private key that avbtool will use to sign this vbmeta image.
 	Private_key *string `android:"path"`

 	// Algorithm that avbtool will use to sign this vbmeta image. Default is SHA256_RSA4096.
 	Algorithm *string

 	// File whose content will provide the rollback index. If unspecified, the rollback index
 	// is from PLATFORM_SECURITY_PATCH
 	Rollback_index_file *string `android:"path"`

 	// Rollback index location of this vbmeta image. Must be 0, 1, 2, etc. Default is 0.
 	Rollback_index_location *int64

 	// List of filesystem modules that this vbmeta has descriptors for. The filesystem modules
 	// have to be signed (use_avb: true).
 	Partitions []string

 	// List of chained partitions that this vbmeta deletages the verification.
 	Chained_partitions []chainedPartitionProperties
 }

 type chainedPartitionProperties struct {
 	// Name of the chained partition
 	Name *string

 	// Rollback index location of the chained partition. Must be 0, 1, 2, etc. Default is the
 	// index of this partition in the list + 1.
 	Rollback_index_location *int64

 	// Path to the public key that the chained partition is signed with. If this is specified,
 	// private_key is ignored.
 	Public_key *string `android:"path"`

 	// Path to the private key that the chained partition is signed with. If this is specified,
 	// and public_key is not specified, a public key is extracted from this private key and
 	// the extracted public key is embedded in the vbmeta image.
 	Private_key *string `android:"path"`
 }

 // vbmeta is the partition image that has the verification information for other partitions.
 func vbmetaFactory() android.Module {
 	module := &vbmeta{}
 	module.AddProperties(&module.properties)
 	android.InitAndroidArchModule(module, android.DeviceSupported, android.MultilibFirst)
 	return module
 }

 type vbmetaDep struct {
 	blueprint.BaseDependencyTag
 	kind string
 }

 var vbmetaPartitionDep = vbmetaDep{kind: "partition"}

 func (v *vbmeta) DepsMutator(ctx android.BottomUpMutatorContext) {
 	ctx.AddDependency(ctx.Module(), vbmetaPartitionDep, v.properties.Partitions...)
 }

 func (v *vbmeta) installFileName() string {
 	return proptools.StringDefault(v.properties.Stem, v.BaseModuleName()+".img")
 }

 func (v *vbmeta) partitionName() string {
 	return proptools.StringDefault(v.properties.Partition_name, v.BaseModuleName())
 }

 // See external/avb/libavb/avb_slot_verify.c#VBMETA_MAX_SIZE
 const vbmetaMaxSize = 64 * 1024

 func (v *vbmeta) GenerateAndroidBuildActions(ctx android.ModuleContext) {
 	extractedPublicKeys := v.extractPublicKeys(ctx)

 	v.output = android.PathForModuleOut(ctx, v.installFileName()).OutputPath

 	builder := android.NewRuleBuilder(pctx, ctx)
 	cmd := builder.Command().BuiltTool("avbtool").Text("make_vbmeta_image")

 	key := android.PathForModuleSrc(ctx, proptools.String(v.properties.Private_key))
 	cmd.FlagWithInput("--key ", key)

 	algorithm := proptools.StringDefault(v.properties.Algorithm, "SHA256_RSA4096")
 	cmd.FlagWithArg("--algorithm ", algorithm)

 	cmd.FlagWithArg("--rollback_index ", v.rollbackIndexCommand(ctx))
 	ril := proptools.IntDefault(v.properties.Rollback_index_location, 0)
 	if ril < 0 {
 		ctx.PropertyErrorf("rollback_index_location", "must be 0, 1, 2, ...")
 		return
 	}
 	cmd.FlagWithArg("--rollback_index_location ", strconv.Itoa(ril))

 	for _, p := range ctx.GetDirectDepsWithTag(vbmetaPartitionDep) {
 		f, ok := p.(Filesystem)
 		if !ok {
 			ctx.PropertyErrorf("partitions", "%q(type: %s) is not supported",
 				p.Name(), ctx.OtherModuleType(p))
 			continue
 		}
 		signedImage := f.SignedOutputPath()
 		if signedImage == nil {
 			ctx.PropertyErrorf("partitions", "%q(type: %s) is not signed. Use `use_avb: true`",
 				p.Name(), ctx.OtherModuleType(p))
 			continue
 		}
 		cmd.FlagWithInput("--include_descriptors_from_image ", signedImage)
 	}

 	for i, cp := range v.properties.Chained_partitions {
 		name := proptools.String(cp.Name)
 		if name == "" {
 			ctx.PropertyErrorf("chained_partitions", "name must be specified")
 			continue
 		}

 		ril := proptools.IntDefault(cp.Rollback_index_location, i+1)
 		if ril < 0 {
 			ctx.PropertyErrorf("chained_partitions", "must be 0, 1, 2, ...")
 			continue
 		}

 		var publicKey android.Path
 		if cp.Public_key != nil {
 			publicKey = android.PathForModuleSrc(ctx, proptools.String(cp.Public_key))
 		} else {
 			publicKey = extractedPublicKeys[name]
 		}
 		cmd.FlagWithArg("--chain_partition ", fmt.Sprintf("%s:%d:%s", name, ril, publicKey.String()))
 		cmd.Implicit(publicKey)
 	}

 	cmd.FlagWithOutput("--output ", v.output)

 	// libavb expects to be able to read the maximum vbmeta size, so we must provide a partition
 	// which matches this or the read will fail.
 	builder.Command().Text("truncate").
 		FlagWithArg("-s ", strconv.Itoa(vbmetaMaxSize)).
 		Output(v.output)

 	builder.Build("vbmeta", fmt.Sprintf("vbmeta %s", ctx.ModuleName()))

 	v.installDir = android.PathForModuleInstall(ctx, "etc")
 	ctx.InstallFile(v.installDir, v.installFileName(), v.output)
 }

 // Returns the embedded shell command that prints the rollback index
 func (v *vbmeta) rollbackIndexCommand(ctx android.ModuleContext) string {
 	var cmd string
 	if v.properties.Rollback_index_file != nil {
 		f := android.PathForModuleSrc(ctx, proptools.String(v.properties.Rollback_index_file))
 		cmd = "cat " + f.String()
 	} else {
 		cmd = "date -d 'TZ=\"GMT\" " + ctx.Config().PlatformSecurityPatch() + "' +%s"
 	}
 	// Take the first line and remove the newline char
 	return "$(" + cmd + " | head -1 | tr -d '\n'" + ")"
 }

 // Extract public keys from chained_partitions.private_key. The keys are indexed with the partition
 // name.
 func (v *vbmeta) extractPublicKeys(ctx android.ModuleContext) map[string]android.OutputPath {
 	result := make(map[string]android.OutputPath)

 	builder := android.NewRuleBuilder(pctx, ctx)
 	for _, cp := range v.properties.Chained_partitions {
 		if cp.Private_key == nil {
 			continue
 		}

 		name := proptools.String(cp.Name)
 		if name == "" {
 			ctx.PropertyErrorf("chained_partitions", "name must be specified")
 			continue
 		}

 		if _, ok := result[name]; ok {
 			ctx.PropertyErrorf("chained_partitions", "name %q is duplicated", name)
 			continue
 		}

 		privateKeyFile := android.PathForModuleSrc(ctx, proptools.String(cp.Private_key))
 		publicKeyFile := android.PathForModuleOut(ctx, name+".avbpubkey").OutputPath

 		builder.Command().
 			BuiltTool("avbtool").
 			Text("extract_public_key").
 			FlagWithInput("--key ", privateKeyFile).
 			FlagWithOutput("--output ", publicKeyFile)

 		result[name] = publicKeyFile
 	}
 	builder.Build("vbmeta_extract_public_key", fmt.Sprintf("Extract public keys for %s", ctx.ModuleName()))
 	return result
 }

 var _ android.AndroidMkEntriesProvider = (*vbmeta)(nil)

 // Implements android.AndroidMkEntriesProvider
 func (v *vbmeta) AndroidMkEntries() []android.AndroidMkEntries {
 	return []android.AndroidMkEntries{android.AndroidMkEntries{
 		Class:      "ETC",
 		OutputFile: android.OptionalPathForPath(v.output),
 		ExtraEntries: []android.AndroidMkExtraEntriesFunc{
 			func(ctx android.AndroidMkExtraEntriesContext, entries *android.AndroidMkEntries) {
 				entries.SetString("LOCAL_MODULE_PATH", v.installDir.ToMakePath().String())
 				entries.SetString("LOCAL_INSTALLED_MODULE_STEM", v.installFileName())
 			},
 		},
 	}}
 }

 var _ Filesystem = (*vbmeta)(nil)

 func (v *vbmeta) OutputPath() android.Path {
 	return v.output
 }

 func (v *vbmeta) SignedOutputPath() android.Path {
 	return v.OutputPath() // vbmeta is always signed
 }

 var _ android.OutputFileProducer = (*vbmeta)(nil)

 // Implements android.OutputFileProducer
 func (v *vbmeta) OutputFiles(tag string) (android.Paths, error) {
 	if tag == "" {
 		return []android.Path{v.output}, nil
 	}
 	return nil, fmt.Errorf("unsupported module reference tag %q", tag)
 }
	// Copyright (C) 2021 The Android Open Source Project
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	package filesystem

	import (
	"fmt"
	"strconv"

	"github.com/google/blueprint"
	"github.com/google/blueprint/proptools"

	"android/soong/android"
	)

	func init() {
	android.RegisterModuleType("vbmeta", vbmetaFactory)
	}

	type vbmeta struct {
	android.ModuleBase

	properties vbmetaProperties

	output android.OutputPath
	installDir android.InstallPath
	}

	type vbmetaProperties struct {
	// Name of the partition stored in vbmeta desc. Defaults to the name of this module.
	Partition_name *string

	// Set the name of the output. Defaults to <module_name>.img.
	Stem *string

	// Path to the private key that avbtool will use to sign this vbmeta image.
	Private_key *string `android:"path"`

	// Algorithm that avbtool will use to sign this vbmeta image. Default is SHA256_RSA4096.
	Algorithm *string

	// File whose content will provide the rollback index. If unspecified, the rollback index
	// is from PLATFORM_SECURITY_PATCH
	Rollback_index_file *string `android:"path"`

	// Rollback index location of this vbmeta image. Must be 0, 1, 2, etc. Default is 0.
	Rollback_index_location *int64

	// List of filesystem modules that this vbmeta has descriptors for. The filesystem modules
	// have to be signed (use_avb: true).
	Partitions []string

	// List of chained partitions that this vbmeta deletages the verification.
	Chained_partitions []chainedPartitionProperties
	}

	type chainedPartitionProperties struct {
	// Name of the chained partition
	Name *string

	// Rollback index location of the chained partition. Must be 0, 1, 2, etc. Default is the
	// index of this partition in the list + 1.
	Rollback_index_location *int64

	// Path to the public key that the chained partition is signed with. If this is specified,
	// private_key is ignored.
	Public_key *string `android:"path"`

	// Path to the private key that the chained partition is signed with. If this is specified,
	// and public_key is not specified, a public key is extracted from this private key and
	// the extracted public key is embedded in the vbmeta image.
	Private_key *string `android:"path"`
	}

	// vbmeta is the partition image that has the verification information for other partitions.
	func vbmetaFactory() android.Module {
	module := &vbmeta{}
	module.AddProperties(&module.properties)
	android.InitAndroidArchModule(module, android.DeviceSupported, android.MultilibFirst)
	return module
	}

	type vbmetaDep struct {
	blueprint.BaseDependencyTag
	kind string
	}

	var vbmetaPartitionDep = vbmetaDep{kind: "partition"}

	func (v *vbmeta) DepsMutator(ctx android.BottomUpMutatorContext) {
	ctx.AddDependency(ctx.Module(), vbmetaPartitionDep, v.properties.Partitions...)
	}

	func (v *vbmeta) installFileName() string {
	return proptools.StringDefault(v.properties.Stem, v.BaseModuleName()+".img")
	}

	func (v *vbmeta) partitionName() string {
	return proptools.StringDefault(v.properties.Partition_name, v.BaseModuleName())
	}

	// See external/avb/libavb/avb_slot_verify.c#VBMETA_MAX_SIZE
	const vbmetaMaxSize = 64 * 1024

	func (v *vbmeta) GenerateAndroidBuildActions(ctx android.ModuleContext) {
	extractedPublicKeys := v.extractPublicKeys(ctx)

	v.output = android.PathForModuleOut(ctx, v.installFileName()).OutputPath

	builder := android.NewRuleBuilder(pctx, ctx)
	cmd := builder.Command().BuiltTool("avbtool").Text("make_vbmeta_image")

	key := android.PathForModuleSrc(ctx, proptools.String(v.properties.Private_key))
	cmd.FlagWithInput("--key ", key)

	algorithm := proptools.StringDefault(v.properties.Algorithm, "SHA256_RSA4096")
	cmd.FlagWithArg("--algorithm ", algorithm)

	cmd.FlagWithArg("--rollback_index ", v.rollbackIndexCommand(ctx))
	ril := proptools.IntDefault(v.properties.Rollback_index_location, 0)
	if ril < 0 {
	ctx.PropertyErrorf("rollback_index_location", "must be 0, 1, 2, ...")
	return
	}
	cmd.FlagWithArg("--rollback_index_location ", strconv.Itoa(ril))

	for _, p := range ctx.GetDirectDepsWithTag(vbmetaPartitionDep) {
	f, ok := p.(Filesystem)
	if !ok {
	ctx.PropertyErrorf("partitions", "%q(type: %s) is not supported",
	p.Name(), ctx.OtherModuleType(p))
	continue
	}
	signedImage := f.SignedOutputPath()
	if signedImage == nil {
	ctx.PropertyErrorf("partitions", "%q(type: %s) is not signed. Use `use_avb: true`",
	p.Name(), ctx.OtherModuleType(p))
	continue
	}
	cmd.FlagWithInput("--include_descriptors_from_image ", signedImage)
	}

	for i, cp := range v.properties.Chained_partitions {
	name := proptools.String(cp.Name)
	if name == "" {
	ctx.PropertyErrorf("chained_partitions", "name must be specified")
	continue
	}

	ril := proptools.IntDefault(cp.Rollback_index_location, i+1)
	if ril < 0 {
	ctx.PropertyErrorf("chained_partitions", "must be 0, 1, 2, ...")
	continue
	}

	var publicKey android.Path
	if cp.Public_key != nil {
	publicKey = android.PathForModuleSrc(ctx, proptools.String(cp.Public_key))
	} else {
	publicKey = extractedPublicKeys[name]
	}
	cmd.FlagWithArg("--chain_partition ", fmt.Sprintf("%s:%d:%s", name, ril, publicKey.String()))
	cmd.Implicit(publicKey)
	}

	cmd.FlagWithOutput("--output ", v.output)

	// libavb expects to be able to read the maximum vbmeta size, so we must provide a partition
	// which matches this or the read will fail.
	builder.Command().Text("truncate").
	FlagWithArg("-s ", strconv.Itoa(vbmetaMaxSize)).
	Output(v.output)

	builder.Build("vbmeta", fmt.Sprintf("vbmeta %s", ctx.ModuleName()))

	v.installDir = android.PathForModuleInstall(ctx, "etc")
	ctx.InstallFile(v.installDir, v.installFileName(), v.output)
	}

	// Returns the embedded shell command that prints the rollback index
	func (v *vbmeta) rollbackIndexCommand(ctx android.ModuleContext) string {
	var cmd string
	if v.properties.Rollback_index_file != nil {
	f := android.PathForModuleSrc(ctx, proptools.String(v.properties.Rollback_index_file))
	cmd = "cat " + f.String()
	} else {
	cmd = "date -d 'TZ=\"GMT\" " + ctx.Config().PlatformSecurityPatch() + "' +%s"
	}
	// Take the first line and remove the newline char
	return "$(" + cmd + " \| head -1 \| tr -d '\n'" + ")"
	}

	// Extract public keys from chained_partitions.private_key. The keys are indexed with the partition
	// name.
	func (v *vbmeta) extractPublicKeys(ctx android.ModuleContext) map[string]android.OutputPath {
	result := make(map[string]android.OutputPath)

	builder := android.NewRuleBuilder(pctx, ctx)
	for _, cp := range v.properties.Chained_partitions {
	if cp.Private_key == nil {
	continue
	}

	name := proptools.String(cp.Name)
	if name == "" {
	ctx.PropertyErrorf("chained_partitions", "name must be specified")
	continue
	}

	if _, ok := result[name]; ok {
	ctx.PropertyErrorf("chained_partitions", "name %q is duplicated", name)
	continue
	}

	privateKeyFile := android.PathForModuleSrc(ctx, proptools.String(cp.Private_key))
	publicKeyFile := android.PathForModuleOut(ctx, name+".avbpubkey").OutputPath

	builder.Command().
	BuiltTool("avbtool").
	Text("extract_public_key").
	FlagWithInput("--key ", privateKeyFile).
	FlagWithOutput("--output ", publicKeyFile)

	result[name] = publicKeyFile
	}
	builder.Build("vbmeta_extract_public_key", fmt.Sprintf("Extract public keys for %s", ctx.ModuleName()))
	return result
	}

	var _ android.AndroidMkEntriesProvider = (*vbmeta)(nil)

	// Implements android.AndroidMkEntriesProvider
	func (v *vbmeta) AndroidMkEntries() []android.AndroidMkEntries {
	return []android.AndroidMkEntries{android.AndroidMkEntries{
	Class: "ETC",
	OutputFile: android.OptionalPathForPath(v.output),
	ExtraEntries: []android.AndroidMkExtraEntriesFunc{
	func(ctx android.AndroidMkExtraEntriesContext, entries *android.AndroidMkEntries) {
	entries.SetString("LOCAL_MODULE_PATH", v.installDir.ToMakePath().String())
	entries.SetString("LOCAL_INSTALLED_MODULE_STEM", v.installFileName())
	},
	},
	}}
	}

	var _ Filesystem = (*vbmeta)(nil)

	func (v *vbmeta) OutputPath() android.Path {
	return v.output
	}

	func (v *vbmeta) SignedOutputPath() android.Path {
	return v.OutputPath() // vbmeta is always signed
	}

	var _ android.OutputFileProducer = (*vbmeta)(nil)

	// Implements android.OutputFileProducer
	func (v *vbmeta) OutputFiles(tag string) (android.Paths, error) {
	if tag == "" {
	return []android.Path{v.output}, nil
	}
	return nil, fmt.Errorf("unsupported module reference tag %q", tag)
	}