metadata: introduce protobuf structures

This commit adds in the metadata package. The primary purpose of this
package is to provide the on-disk metadata structures in the form of
protocol buffers. This includes:
	- Policy metadata structure
	- Protector metadata structure
	- Config file structure
	- All necessary sub-structures (wrapped keys, parameters, etc)

This commit also adds in an example usage of the Config structure, which
represents the structure of the global config file. All the package
does at this point is convert between the Config structure and a JSON
representation.

Here we introduce govendor, which is described more in the README. This
means we will have all of our Go dependencies in the vendor
subdirectory. This means we will have no Go source dependencies, only
dependencies on the build tools (Go and govendor). The README describes
this in detail.

Note that we commit the generated files.
  see: https://blog.golang.org/generate

Change-Id: Iaacd46666b5d3e4e865a0f4045dd63ed7e3d6f96

1 files changed, 415 insertions, 0 deletions

diff --git a/metadata/metadata.pb.go b/metadata/metadata.pb.go
new file mode 100644
index 0000000..68001e9
--- /dev/null
+++ b/metadata/metadata.pb.go
@@ -0,0 +1,415 @@
+// Code generated by protoc-gen-go.
+// source: metadata.proto
+// DO NOT EDIT!
+
+/*
+Package metadata is a generated protocol buffer package.
+
+It is generated from these files:
+	metadata.proto
+
+It has these top-level messages:
+	HashingCosts
+	WrappedKeyData
+	ProtectorData
+	EncryptionOptions
+	WrappedPolicyKey
+	PolicyData
+	Config
+*/
+package metadata
+
+import proto "github.com/golang/protobuf/proto"
+import fmt "fmt"
+import math "math"
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.ProtoPackageIsVersion2 // please upgrade the proto package
+
+// Specifies the method in which an outside secret is obtained for a Protector
+type SourceType int32
+
+const (
+	SourceType_none              SourceType = 0
+	SourceType_pam_passphrase    SourceType = 1
+	SourceType_custom_passphrase SourceType = 2
+	SourceType_raw_key           SourceType = 3
+)
+
+var SourceType_name = map[int32]string{
+	0: "none",
+	1: "pam_passphrase",
+	2: "custom_passphrase",
+	3: "raw_key",
+}
+var SourceType_value = map[string]int32{
+	"none":              0,
+	"pam_passphrase":    1,
+	"custom_passphrase": 2,
+	"raw_key":           3,
+}
+
+func (x SourceType) String() string {
+	return proto.EnumName(SourceType_name, int32(x))
+}
+func (SourceType) EnumDescriptor() ([]byte, []int) { return fileDescriptor0, []int{0} }
+
+// Type of encryption, should match the declarations of FS_ENCRYPTION_MODE
+type EncryptionMode int32
+
+const (
+	EncryptionMode_default EncryptionMode = 0
+	EncryptionMode_XTS     EncryptionMode = 1
+	EncryptionMode_GCM     EncryptionMode = 2
+	EncryptionMode_CBC     EncryptionMode = 3
+	EncryptionMode_CTS     EncryptionMode = 4
+)
+
+var EncryptionMode_name = map[int32]string{
+	0: "default",
+	1: "XTS",
+	2: "GCM",
+	3: "CBC",
+	4: "CTS",
+}
+var EncryptionMode_value = map[string]int32{
+	"default": 0,
+	"XTS":     1,
+	"GCM":     2,
+	"CBC":     3,
+	"CTS":     4,
+}
+
+func (x EncryptionMode) String() string {
+	return proto.EnumName(EncryptionMode_name, int32(x))
+}
+func (EncryptionMode) EnumDescriptor() ([]byte, []int) { return fileDescriptor0, []int{1} }
+
+// Cost parameters to be used in our hashing functions.
+type HashingCosts struct {
+	Time        int64 `protobuf:"varint,2,opt,name=time" json:"time,omitempty"`
+	Memory      int64 `protobuf:"varint,3,opt,name=memory" json:"memory,omitempty"`
+	Parallelism int64 `protobuf:"varint,4,opt,name=parallelism" json:"parallelism,omitempty"`
+}
+
+func (m *HashingCosts) Reset()                    { *m = HashingCosts{} }
+func (m *HashingCosts) String() string            { return proto.CompactTextString(m) }
+func (*HashingCosts) ProtoMessage()               {}
+func (*HashingCosts) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{0} }
+
+func (m *HashingCosts) GetTime() int64 {
+	if m != nil {
+		return m.Time
+	}
+	return 0
+}
+
+func (m *HashingCosts) GetMemory() int64 {
+	if m != nil {
+		return m.Memory
+	}
+	return 0
+}
+
+func (m *HashingCosts) GetParallelism() int64 {
+	if m != nil {
+		return m.Parallelism
+	}
+	return 0
+}
+
+// This structure is used for our authenticated wrapping/unwrapping of keys.
+type WrappedKeyData struct {
+	IV           []byte `protobuf:"bytes,1,opt,name=IV,proto3" json:"IV,omitempty"`
+	EncryptedKey []byte `protobuf:"bytes,2,opt,name=encrypted_key,json=encryptedKey,proto3" json:"encrypted_key,omitempty"`
+	Hmac         []byte `protobuf:"bytes,3,opt,name=hmac,proto3" json:"hmac,omitempty"`
+}
+
+func (m *WrappedKeyData) Reset()                    { *m = WrappedKeyData{} }
+func (m *WrappedKeyData) String() string            { return proto.CompactTextString(m) }
+func (*WrappedKeyData) ProtoMessage()               {}
+func (*WrappedKeyData) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{1} }
+
+func (m *WrappedKeyData) GetIV() []byte {
+	if m != nil {
+		return m.IV
+	}
+	return nil
+}
+
+func (m *WrappedKeyData) GetEncryptedKey() []byte {
+	if m != nil {
+		return m.EncryptedKey
+	}
+	return nil
+}
+
+func (m *WrappedKeyData) GetHmac() []byte {
+	if m != nil {
+		return m.Hmac
+	}
+	return nil
+}
+
+// The associated data for each protector
+type ProtectorData struct {
+	ProtectorDescriptor string     `protobuf:"bytes,1,opt,name=protector_descriptor,json=protectorDescriptor" json:"protector_descriptor,omitempty"`
+	Name                string     `protobuf:"bytes,2,opt,name=name" json:"name,omitempty"`
+	Source              SourceType `protobuf:"varint,3,opt,name=source,enum=metadata.SourceType" json:"source,omitempty"`
+	// These are only used by some of the protector types
+	Costs      *HashingCosts   `protobuf:"bytes,4,opt,name=costs" json:"costs,omitempty"`
+	Salt       []byte          `protobuf:"bytes,5,opt,name=salt,proto3" json:"salt,omitempty"`
+	Uid        int64           `protobuf:"varint,6,opt,name=uid" json:"uid,omitempty"`
+	WrappedKey *WrappedKeyData `protobuf:"bytes,7,opt,name=wrapped_key,json=wrappedKey" json:"wrapped_key,omitempty"`
+}
+
+func (m *ProtectorData) Reset()                    { *m = ProtectorData{} }
+func (m *ProtectorData) String() string            { return proto.CompactTextString(m) }
+func (*ProtectorData) ProtoMessage()               {}
+func (*ProtectorData) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{2} }
+
+func (m *ProtectorData) GetProtectorDescriptor() string {
+	if m != nil {
+		return m.ProtectorDescriptor
+	}
+	return ""
+}
+
+func (m *ProtectorData) GetName() string {
+	if m != nil {
+		return m.Name
+	}
+	return ""
+}
+
+func (m *ProtectorData) GetSource() SourceType {
+	if m != nil {
+		return m.Source
+	}
+	return SourceType_none
+}
+
+func (m *ProtectorData) GetCosts() *HashingCosts {
+	if m != nil {
+		return m.Costs
+	}
+	return nil
+}
+
+func (m *ProtectorData) GetSalt() []byte {
+	if m != nil {
+		return m.Salt
+	}
+	return nil
+}
+
+func (m *ProtectorData) GetUid() int64 {
+	if m != nil {
+		return m.Uid
+	}
+	return 0
+}
+
+func (m *ProtectorData) GetWrappedKey() *WrappedKeyData {
+	if m != nil {
+		return m.WrappedKey
+	}
+	return nil
+}
+
+// Encryption policy specifics, should match struct fscrypt_policy
+type EncryptionOptions struct {
+	Padding       int64          `protobuf:"varint,1,opt,name=padding" json:"padding,omitempty"`
+	ContentsMode  EncryptionMode `protobuf:"varint,2,opt,name=contents_mode,json=contentsMode,enum=metadata.EncryptionMode" json:"contents_mode,omitempty"`
+	FilenamesMode EncryptionMode `protobuf:"varint,3,opt,name=filenames_mode,json=filenamesMode,enum=metadata.EncryptionMode" json:"filenames_mode,omitempty"`
+}
+
+func (m *EncryptionOptions) Reset()                    { *m = EncryptionOptions{} }
+func (m *EncryptionOptions) String() string            { return proto.CompactTextString(m) }
+func (*EncryptionOptions) ProtoMessage()               {}
+func (*EncryptionOptions) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{3} }
+
+func (m *EncryptionOptions) GetPadding() int64 {
+	if m != nil {
+		return m.Padding
+	}
+	return 0
+}
+
+func (m *EncryptionOptions) GetContentsMode() EncryptionMode {
+	if m != nil {
+		return m.ContentsMode
+	}
+	return EncryptionMode_default
+}
+
+func (m *EncryptionOptions) GetFilenamesMode() EncryptionMode {
+	if m != nil {
+		return m.FilenamesMode
+	}
+	return EncryptionMode_default
+}
+
+type WrappedPolicyKey struct {
+	ProtectorDescriptor string          `protobuf:"bytes,1,opt,name=protector_descriptor,json=protectorDescriptor" json:"protector_descriptor,omitempty"`
+	WrappedKey          *WrappedKeyData `protobuf:"bytes,2,opt,name=wrapped_key,json=wrappedKey" json:"wrapped_key,omitempty"`
+}
+
+func (m *WrappedPolicyKey) Reset()                    { *m = WrappedPolicyKey{} }
+func (m *WrappedPolicyKey) String() string            { return proto.CompactTextString(m) }
+func (*WrappedPolicyKey) ProtoMessage()               {}
+func (*WrappedPolicyKey) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{4} }
+
+func (m *WrappedPolicyKey) GetProtectorDescriptor() string {
+	if m != nil {
+		return m.ProtectorDescriptor
+	}
+	return ""
+}
+
+func (m *WrappedPolicyKey) GetWrappedKey() *WrappedKeyData {
+	if m != nil {
+		return m.WrappedKey
+	}
+	return nil
+}
+
+// The associated data for each policy
+type PolicyData struct {
+	KeyDescriptor     string              `protobuf:"bytes,1,opt,name=key_descriptor,json=keyDescriptor" json:"key_descriptor,omitempty"`
+	Options           *EncryptionOptions  `protobuf:"bytes,2,opt,name=options" json:"options,omitempty"`
+	WrappedPolicyKeys []*WrappedPolicyKey `protobuf:"bytes,3,rep,name=wrapped_policy_keys,json=wrappedPolicyKeys" json:"wrapped_policy_keys,omitempty"`
+}
+
+func (m *PolicyData) Reset()                    { *m = PolicyData{} }
+func (m *PolicyData) String() string            { return proto.CompactTextString(m) }
+func (*PolicyData) ProtoMessage()               {}
+func (*PolicyData) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{5} }
+
+func (m *PolicyData) GetKeyDescriptor() string {
+	if m != nil {
+		return m.KeyDescriptor
+	}
+	return ""
+}
+
+func (m *PolicyData) GetOptions() *EncryptionOptions {
+	if m != nil {
+		return m.Options
+	}
+	return nil
+}
+
+func (m *PolicyData) GetWrappedPolicyKeys() []*WrappedPolicyKey {
+	if m != nil {
+		return m.WrappedPolicyKeys
+	}
+	return nil
+}
+
+// Data stored in the config file
+type Config struct {
+	Source        SourceType         `protobuf:"varint,1,opt,name=source,enum=metadata.SourceType" json:"source,omitempty"`
+	HashCosts     *HashingCosts      `protobuf:"bytes,2,opt,name=hash_costs,json=hashCosts" json:"hash_costs,omitempty"`
+	Compatibility string             `protobuf:"bytes,3,opt,name=compatibility" json:"compatibility,omitempty"`
+	Options       *EncryptionOptions `protobuf:"bytes,4,opt,name=options" json:"options,omitempty"`
+}
+
+func (m *Config) Reset()                    { *m = Config{} }
+func (m *Config) String() string            { return proto.CompactTextString(m) }
+func (*Config) ProtoMessage()               {}
+func (*Config) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{6} }
+
+func (m *Config) GetSource() SourceType {
+	if m != nil {
+		return m.Source
+	}
+	return SourceType_none
+}
+
+func (m *Config) GetHashCosts() *HashingCosts {
+	if m != nil {
+		return m.HashCosts
+	}
+	return nil
+}
+
+func (m *Config) GetCompatibility() string {
+	if m != nil {
+		return m.Compatibility
+	}
+	return ""
+}
+
+func (m *Config) GetOptions() *EncryptionOptions {
+	if m != nil {
+		return m.Options
+	}
+	return nil
+}
+
+func init() {
+	proto.RegisterType((*HashingCosts)(nil), "metadata.HashingCosts")
+	proto.RegisterType((*WrappedKeyData)(nil), "metadata.WrappedKeyData")
+	proto.RegisterType((*ProtectorData)(nil), "metadata.ProtectorData")
+	proto.RegisterType((*EncryptionOptions)(nil), "metadata.EncryptionOptions")
+	proto.RegisterType((*WrappedPolicyKey)(nil), "metadata.WrappedPolicyKey")
+	proto.RegisterType((*PolicyData)(nil), "metadata.PolicyData")
+	proto.RegisterType((*Config)(nil), "metadata.Config")
+	proto.RegisterEnum("metadata.SourceType", SourceType_name, SourceType_value)
+	proto.RegisterEnum("metadata.EncryptionMode", EncryptionMode_name, EncryptionMode_value)
+}
+
+func init() { proto.RegisterFile("metadata.proto", fileDescriptor0) }
+
+var fileDescriptor0 = []byte{
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+}