DockerCLI/vendor/github.com/theupdateframework/notary/tuf/data/timestamp.go

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package data
import (
"bytes"
"fmt"
"github.com/docker/go/canonical/json"
"github.com/theupdateframework/notary"
)
// SignedTimestamp is a fully unpacked timestamp.json
type SignedTimestamp struct {
Signatures []Signature
Signed Timestamp
Dirty bool
}
// Timestamp is the Signed component of a timestamp.json
type Timestamp struct {
SignedCommon
Meta Files `json:"meta"`
}
// IsValidTimestampStructure returns an error, or nil, depending on whether the content of the struct
// is valid for timestamp metadata. This does not check signatures or expiry, just that
// the metadata content is valid.
func IsValidTimestampStructure(t Timestamp) error {
expectedType := TUFTypes[CanonicalTimestampRole]
if t.Type != expectedType {
return ErrInvalidMetadata{
role: CanonicalTimestampRole, msg: fmt.Sprintf("expected type %s, not %s", expectedType, t.Type)}
}
if t.Version < 1 {
return ErrInvalidMetadata{
role: CanonicalTimestampRole, msg: "version cannot be less than one"}
}
// Meta is a map of FileMeta, so if the role isn't in the map it returns
// an empty FileMeta, which has an empty map, and you can check on keys
// from an empty map.
//
// For now sha256 is required and sha512 is not.
if _, ok := t.Meta[CanonicalSnapshotRole.String()].Hashes[notary.SHA256]; !ok {
return ErrInvalidMetadata{
role: CanonicalTimestampRole, msg: "missing snapshot sha256 checksum information"}
}
if err := CheckValidHashStructures(t.Meta[CanonicalSnapshotRole.String()].Hashes); err != nil {
return ErrInvalidMetadata{
role: CanonicalTimestampRole, msg: fmt.Sprintf("invalid snapshot checksum information, %v", err)}
}
return nil
}
// NewTimestamp initializes a timestamp with an existing snapshot
func NewTimestamp(snapshot *Signed) (*SignedTimestamp, error) {
snapshotJSON, err := json.Marshal(snapshot)
if err != nil {
return nil, err
}
snapshotMeta, err := NewFileMeta(bytes.NewReader(snapshotJSON), NotaryDefaultHashes...)
if err != nil {
return nil, err
}
return &SignedTimestamp{
Signatures: make([]Signature, 0),
Signed: Timestamp{
SignedCommon: SignedCommon{
Type: TUFTypes[CanonicalTimestampRole],
Version: 0,
Expires: DefaultExpires(CanonicalTimestampRole),
},
Meta: Files{
CanonicalSnapshotRole.String(): snapshotMeta,
},
},
}, nil
}
// ToSigned partially serializes a SignedTimestamp such that it can
// be signed
func (ts *SignedTimestamp) ToSigned() (*Signed, error) {
s, err := defaultSerializer.MarshalCanonical(ts.Signed)
if err != nil {
return nil, err
}
signed := json.RawMessage{}
err = signed.UnmarshalJSON(s)
if err != nil {
return nil, err
}
sigs := make([]Signature, len(ts.Signatures))
copy(sigs, ts.Signatures)
return &Signed{
Signatures: sigs,
Signed: &signed,
}, nil
}
// GetSnapshot gets the expected snapshot metadata hashes in the timestamp metadata,
// or nil if it doesn't exist
func (ts *SignedTimestamp) GetSnapshot() (*FileMeta, error) {
snapshotExpected, ok := ts.Signed.Meta[CanonicalSnapshotRole.String()]
if !ok {
return nil, ErrMissingMeta{Role: CanonicalSnapshotRole.String()}
}
return &snapshotExpected, nil
}
// MarshalJSON returns the serialized form of SignedTimestamp as bytes
func (ts *SignedTimestamp) MarshalJSON() ([]byte, error) {
signed, err := ts.ToSigned()
if err != nil {
return nil, err
}
return defaultSerializer.Marshal(signed)
}
// TimestampFromSigned parsed a Signed object into a fully unpacked
// SignedTimestamp
func TimestampFromSigned(s *Signed) (*SignedTimestamp, error) {
ts := Timestamp{}
if err := defaultSerializer.Unmarshal(*s.Signed, &ts); err != nil {
return nil, err
}
if err := IsValidTimestampStructure(ts); err != nil {
return nil, err
}
sigs := make([]Signature, len(s.Signatures))
copy(sigs, s.Signatures)
return &SignedTimestamp{
Signatures: sigs,
Signed: ts,
}, nil
}