forked from endophage/gotuf
/
tuf.go
612 lines (564 loc) · 15.8 KB
/
tuf.go
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// tuf defines the core TUF logic around manipulating a repo.
package tuf
import (
"bytes"
"crypto/sha256"
"encoding/hex"
"encoding/json"
"fmt"
"path/filepath"
"time"
"github.com/Sirupsen/logrus"
"github.com/endophage/gotuf/data"
"github.com/endophage/gotuf/errors"
"github.com/endophage/gotuf/keys"
"github.com/endophage/gotuf/signed"
"github.com/endophage/gotuf/utils"
)
type ErrSigVerifyFail struct{}
func (e ErrSigVerifyFail) Error() string {
return "Error: Signature verification failed"
}
type ErrMetaExpired struct{}
func (e ErrMetaExpired) Error() string {
return "Error: Metadata has expired"
}
type ErrLocalRootExpired struct{}
func (e ErrLocalRootExpired) Error() string {
return "Error: Local Root Has Expired"
}
type ErrNotLoaded struct {
role string
}
func (err *ErrNotLoaded) Error() string {
return fmt.Sprintf("%s role has not been loaded", err.role)
}
// TufRepo is an in memory representation of the TUF Repo.
// It operates at the data.Signed level, accepting and producing
// data.Signed objects. Users of a TufRepo are responsible for
// fetching raw JSON and using the Set* functions to populate
// the TufRepo instance.
type TufRepo struct {
Root *data.SignedRoot
Targets map[string]*data.SignedTargets
Snapshot *data.SignedSnapshot
Timestamp *data.SignedTimestamp
keysDB *keys.KeyDB
signer *signed.Signer
}
// NewTufRepo initializes a TufRepo instance with a keysDB and a signer.
// If the TufRepo will only be used for reading, the signer should be nil.
func NewTufRepo(keysDB *keys.KeyDB, signer *signed.Signer) *TufRepo {
repo := &TufRepo{
Targets: make(map[string]*data.SignedTargets),
keysDB: keysDB,
signer: signer,
}
return repo
}
// AddBaseKeys is used to add keys to the role in root.json
func (tr *TufRepo) AddBaseKeys(role string, keys ...data.Key) error {
if tr.Root == nil {
return &ErrNotLoaded{role: "root"}
}
for _, k := range keys {
key := data.NewPublicKey(k.Cipher(), k.Public())
tr.Root.Signed.Keys[key.ID()] = key
tr.keysDB.AddKey(key)
tr.Root.Signed.Roles[role].KeyIDs = append(tr.Root.Signed.Roles[role].KeyIDs, key.ID())
}
tr.Root.Dirty = true
return nil
}
// RemoveKeys is used to remove keys from the roles in root.json
func (tr *TufRepo) RemoveBaseKeys(role string, keyIDs ...string) error {
if tr.Root == nil {
return &ErrNotLoaded{role: "root"}
}
keep := make([]string, 0)
toDelete := make(map[string]struct{})
// remove keys from specified role
for _, k := range keyIDs {
toDelete[k] = struct{}{}
for _, rk := range tr.Root.Signed.Roles[role].KeyIDs {
if k != rk {
keep = append(keep, rk)
}
}
}
tr.Root.Signed.Roles[role].KeyIDs = keep
// determine which keys are no longer in use by any roles
for roleName, r := range tr.Root.Signed.Roles {
if roleName == role {
continue
}
for _, rk := range r.KeyIDs {
if _, ok := toDelete[rk]; ok {
delete(toDelete, rk)
}
}
}
// remove keys no longer in use by any roles
for k, _ := range toDelete {
delete(tr.Root.Signed.Keys, k)
}
tr.Root.Dirty = true
return nil
}
// UpdateDelegations updates the appropriate delegations, either adding
// a new delegation or updating an existing one. If keys are
// provided, the IDs will be added to the role (if they do not exist
// there already), and the keys will be added to the targets file.
// The "before" argument specifies another role which this new role
// will be added in front of (i.e. higher priority) in the delegation list.
// An empty before string indicates to add the role to the end of the
// delegation list.
// A new, empty, targets file will be created for the new role.
func (tr *TufRepo) UpdateDelegations(role *data.Role, keys []data.Key, before string) error {
if !role.IsDelegation() || !role.IsValid() {
return errors.ErrInvalidRole{}
}
parent := filepath.Dir(role.Name)
p, ok := tr.Targets[parent]
if !ok {
return errors.ErrInvalidRole{}
}
for _, k := range keys {
key := data.NewPublicKey(k.Cipher(), k.Public())
if !utils.StrSliceContains(role.KeyIDs, key.ID()) {
role.KeyIDs = append(role.KeyIDs, key.ID())
}
p.Signed.Delegations.Keys[key.ID()] = key
tr.keysDB.AddKey(key)
}
i := -1
var r *data.Role
for i, r = range p.Signed.Delegations.Roles {
if r.Name == role.Name {
break
}
}
if i >= 0 {
p.Signed.Delegations.Roles[i] = role
} else {
p.Signed.Delegations.Roles = append(p.Signed.Delegations.Roles, role)
}
p.Dirty = true
roleTargets := data.NewTargets() // NewTargets always marked Dirty
tr.Targets[role.Name] = roleTargets
tr.keysDB.AddRole(role)
return nil
}
// InitRepo creates the base files for a repo. It inspects data.ValidRoles and
// data.ValidTypes to determine what the role names and filename should be. It
// also relies on the keysDB having already been populated with the keys and
// roles.
func (tr *TufRepo) InitRepo(consistent bool) error {
err := tr.InitRoot(consistent)
if err != nil {
return err
}
tr.InitTargets()
if err != nil {
return err
}
tr.InitSnapshot()
if err != nil {
return err
}
return tr.InitTimestamp()
}
func (tr *TufRepo) InitRoot(consistent bool) error {
rootRoles := make(map[string]*data.RootRole)
rootKeys := make(map[string]*data.PublicKey)
for _, r := range data.ValidRoles {
role := tr.keysDB.GetRole(r)
if role == nil {
return errors.ErrInvalidRole{}
}
rootRoles[r] = &role.RootRole
for _, kid := range role.KeyIDs {
// don't need to check if GetKey returns nil, Key presence was
// checked by KeyDB when role was added.
key := tr.keysDB.GetKey(kid)
// Create new key object to doubly ensure private key is excluded
k := data.NewPublicKey(key.Cipher(), key.Public())
rootKeys[kid] = k
}
}
root, err := data.NewRoot(rootKeys, rootRoles, consistent)
if err != nil {
return err
}
tr.Root = root
return nil
}
func (tr *TufRepo) InitTargets() error {
targets := data.NewTargets()
tr.Targets[data.ValidRoles["targets"]] = targets
return nil
}
func (tr *TufRepo) InitSnapshot() error {
signedRoot, err := tr.SignRoot(data.DefaultExpires("root"), nil)
if err != nil {
return err
}
signedTargets, err := tr.SignTargets("targets", data.DefaultExpires("targets"), nil)
if err != nil {
return err
}
snapshot, err := data.NewSnapshot(signedRoot, signedTargets)
if err != nil {
return err
}
tr.Snapshot = snapshot
return nil
}
func (tr *TufRepo) InitTimestamp() error {
signedSnapshot, err := tr.SignSnapshot(data.DefaultExpires("snapshot"), nil)
if err != nil {
return err
}
timestamp, err := data.NewTimestamp(signedSnapshot)
if err != nil {
return err
}
tr.Timestamp = timestamp
return nil
}
// SetRoot parses the Signed object into a SignedRoot object, sets
// the keys and roles in the KeyDB, and sets the TufRepo.Root field
// to the SignedRoot object.
func (tr *TufRepo) SetRoot(s *data.Signed) error {
r, err := data.RootFromSigned(s)
if err != nil {
return err
}
for kid, key := range r.Signed.Keys {
tr.keysDB.AddKey(key)
logrus.Debug("Given Key ID:", kid, "\nGenerated Key ID:", key.ID())
}
for roleName, role := range r.Signed.Roles {
baseRole, err := data.NewRole(
roleName,
role.Threshold,
role.KeyIDs,
nil,
nil,
)
if err != nil {
return err
}
err = tr.keysDB.AddRole(baseRole)
if err != nil {
return err
}
}
tr.Root = r
return nil
}
// SetTimestamp parses the Signed object into a SignedTimestamp object
// and sets the TufRepo.Timestamp field.
func (tr *TufRepo) SetTimestamp(s *data.Signed) error {
ts, err := data.TimestampFromSigned(s)
if err != nil {
return err
}
tr.Timestamp = ts
return nil
}
// SetSnapshot parses the Signed object into a SignedSnapshots object
// and sets the TufRepo.Snapshot field.
func (tr *TufRepo) SetSnapshot(s *data.Signed) error {
snap, err := data.SnapshotFromSigned(s)
if err != nil {
return err
}
tr.Snapshot = snap
return nil
}
// SetTargets parses the Signed object into a SignedTargets object,
// reads the delegated roles and keys into the KeyDB, and sets the
// SignedTargets object agaist the role in the TufRepo.Targets map.
func (tr *TufRepo) SetTargets(role string, s *data.Signed) error {
t, err := data.TargetsFromSigned(s)
if err != nil {
return err
}
for _, k := range t.Signed.Delegations.Keys {
tr.keysDB.AddKey(k)
}
for _, r := range t.Signed.Delegations.Roles {
tr.keysDB.AddRole(r)
}
tr.Targets[role] = t
return nil
}
// TargetMeta returns the FileMeta entry for the given path in the
// targets file associated with the given role. This may be nil if
// the target isn't found in the targets file.
func (tr TufRepo) TargetMeta(role, path string) *data.FileMeta {
if t, ok := tr.Targets[role]; ok {
if m, ok := t.Signed.Targets[path]; ok {
return &m
}
}
return nil
}
// TargetDelegations returns a slice of Roles that are valid publishers
// for the target path provided.
func (tr TufRepo) TargetDelegations(role, path, pathHex string) []*data.Role {
if pathHex == "" {
pathDigest := sha256.Sum256([]byte(path))
pathHex = hex.EncodeToString(pathDigest[:])
}
roles := make([]*data.Role, 0)
if t, ok := tr.Targets[role]; ok {
for _, r := range t.Signed.Delegations.Roles {
if r.CheckPrefixes(pathHex) || r.CheckPaths(path) {
roles = append(roles, r)
}
}
}
return roles
}
// FindTarget attempts to find the target represented by the given
// path by starting at the top targets file and traversing
// appropriate delegations until the first entry is found or it
// runs out of locations to search.
// N.B. Multiple entries may exist in different delegated roles
// for the same target. Only the first one encountered is returned.
func (tr TufRepo) FindTarget(path string) *data.FileMeta {
pathDigest := sha256.Sum256([]byte(path))
pathHex := hex.EncodeToString(pathDigest[:])
var walkTargets func(role string) *data.FileMeta
walkTargets = func(role string) *data.FileMeta {
if m := tr.TargetMeta(role, path); m != nil {
return m
}
// Depth first search of delegations based on order
// as presented in current targets file for role:
for _, r := range tr.TargetDelegations(role, path, pathHex) {
if m := walkTargets(r.Name); m != nil {
return m
}
}
return nil
}
return walkTargets("targets")
}
// AddTargets will attempt to add the given targets specifically to
// the directed role. If the user does not have the signing keys for the role
// the function will return an error and the full slice of targets.
func (tr *TufRepo) AddTargets(role string, targets data.Files) (data.Files, error) {
t, ok := tr.Targets[role]
if !ok {
return targets, errors.ErrInvalidRole{role}
}
invalid := make(data.Files)
for path, target := range targets {
pathDigest := sha256.Sum256([]byte(path))
pathHex := hex.EncodeToString(pathDigest[:])
r := tr.keysDB.GetRole(role)
if role == data.ValidRoles["targets"] || (r.CheckPaths(path) || r.CheckPrefixes(pathHex)) {
t.Signed.Targets[path] = target
} else {
invalid[path] = target
}
}
t.Dirty = true
if len(invalid) > 0 {
return invalid, fmt.Errorf("Could not add all targets")
}
return nil, nil
}
func (tr *TufRepo) RemoveTargets(role string, targets ...string) error {
t, ok := tr.Targets[role]
if !ok {
return errors.ErrInvalidRole{role}
}
for _, path := range targets {
delete(t.Signed.Targets, path)
}
t.Dirty = true
return nil
}
func (tr *TufRepo) UpdateSnapshot(role string, s *data.Signed) error {
jsonData, err := json.Marshal(s)
if err != nil {
return err
}
meta, err := data.NewFileMeta(bytes.NewReader(jsonData), "sha256")
if err != nil {
return err
}
tr.Snapshot.Signed.Meta[role] = meta
tr.Snapshot.Dirty = true
return nil
}
func (tr *TufRepo) UpdateTimestamp(s *data.Signed) error {
jsonData, err := json.Marshal(s)
if err != nil {
return err
}
meta, err := data.NewFileMeta(bytes.NewReader(jsonData), "sha256")
if err != nil {
return err
}
tr.Timestamp.Signed.Meta["snapshot"] = meta
tr.Timestamp.Dirty = true
return nil
}
func (tr *TufRepo) SignRoot(expires time.Time, signer *signed.Signer) (*data.Signed, error) {
logrus.Debug("SignRoot")
if tr.Root.Dirty {
tr.Root.Signed.Version++
}
root := tr.keysDB.GetRole(data.ValidRoles["root"])
signed, err := tr.Root.ToSigned()
if err != nil {
return nil, err
}
signed, err = tr.sign(signed, *root, signer)
if err != nil {
return nil, err
}
tr.Root.Signatures = signed.Signatures
return signed, nil
}
func (tr *TufRepo) SignTargets(role string, expires time.Time, signer *signed.Signer) (*data.Signed, error) {
logrus.Debug("SignTargets")
logrus.Debug("Got targets data.Signed object")
if tr.Targets[role].Dirty {
tr.Targets[role].Signed.Version++
signed, err := tr.Targets[role].ToSigned()
if err != nil {
logrus.Debug("errored getting targets data.Signed object")
return nil, err
}
targets := tr.keysDB.GetRole(role)
logrus.Debug("About to sign ", role)
signed, err = tr.sign(signed, *targets, signer)
if err != nil {
logrus.Debug("errored signing ", role)
return nil, err
}
logrus.Debug("success signing ", role)
tr.Targets[role].Signatures = signed.Signatures
return signed, nil
} else {
signed, err := tr.Targets[role].ToSigned()
if err != nil {
logrus.Debug("errored getting targets data.Signed object")
return nil, err
}
return signed, nil
}
}
func (tr *TufRepo) SignSnapshot(expires time.Time, signer *signed.Signer) (*data.Signed, error) {
logrus.Debug("SignSnapshot")
if tr.Root.Dirty {
signedRoot, err := tr.SignRoot(data.DefaultExpires("root"), signer)
if err != nil {
return nil, err
}
err = tr.UpdateSnapshot("root", signedRoot)
if err != nil {
return nil, err
}
tr.Root.Dirty = false // root dirty until changes captures in snapshot
}
for role, targets := range tr.Targets {
if !targets.Dirty {
continue
}
signedTargets, err := tr.SignTargets(role, data.DefaultExpires("targets"), signer)
if err != nil {
return nil, err
}
err = tr.UpdateSnapshot(role, signedTargets)
if err != nil {
return nil, err
}
tr.Targets[role].Dirty = false // target role dirty until changes captured in snapshot
}
if tr.Snapshot.Dirty {
tr.Snapshot.Signed.Version++
signed, err := tr.Snapshot.ToSigned()
if err != nil {
return nil, err
}
snapshot := tr.keysDB.GetRole(data.ValidRoles["snapshot"])
signed, err = tr.sign(signed, *snapshot, signer)
if err != nil {
return nil, err
}
tr.Snapshot.Signatures = signed.Signatures
return signed, nil
} else {
signed, err := tr.Snapshot.ToSigned()
if err != nil {
return nil, err
}
return signed, nil
}
}
func (tr *TufRepo) SignTimestamp(expires time.Time, signer *signed.Signer) (*data.Signed, error) {
logrus.Debug("SignTimestamp")
if tr.Snapshot.Dirty {
signedSnapshot, err := tr.SignSnapshot(data.DefaultExpires("snapshot"), signer)
if err != nil {
return nil, err
}
err = tr.UpdateTimestamp(signedSnapshot)
if err != nil {
return nil, err
}
}
if tr.Timestamp.Dirty {
tr.Timestamp.Signed.Version++
signed, err := tr.Timestamp.ToSigned()
if err != nil {
return nil, err
}
timestamp := tr.keysDB.GetRole(data.ValidRoles["timestamp"])
signed, err = tr.sign(signed, *timestamp, signer)
if err != nil {
return nil, err
}
tr.Timestamp.Signatures = signed.Signatures
tr.Snapshot.Dirty = false // snapshot is dirty until changes have been captured in timestamp
return signed, nil
} else {
signed, err := tr.Timestamp.ToSigned()
if err != nil {
return nil, err
}
return signed, nil
}
}
func (tr TufRepo) sign(signed *data.Signed, role data.Role, signer *signed.Signer) (*data.Signed, error) {
ks := make([]*data.PublicKey, 0, len(role.KeyIDs))
for _, kid := range role.KeyIDs {
k := tr.keysDB.GetKey(kid)
if k == nil {
continue
}
ks = append(ks, k)
}
if len(ks) < 1 {
return nil, keys.ErrInvalidKey
}
if signer != nil {
err := signer.Sign(signed, ks...)
if err != nil {
return nil, err
}
} else {
err := tr.signer.Sign(signed, ks...)
if err != nil {
return nil, err
}
}
return signed, nil
}