go/ucan
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

invocation: split out the delegation chain control

Browse Source
This commit is contained in:
Michael Muré
2024-11-13 16:58:48 +01:00
parent 92065ca0d3
commit 64b989452f
5 changed files with 162 additions and 82 deletions
Download Patch File Download Diff File Expand all files Collapse all files

72
token/invocation/invocation.go
View File

@@ -126,6 +126,7 @@ func New(iss, sub did.DID, cmd command.Command, prf []cid.Cid, opts ...Option) (
}
}
var err error
if len(tkn.nonce) == 0 {
tkn.nonce, err = nonce.Generate()
if err != nil {
@@ -140,10 +141,6 @@ func New(iss, sub did.DID, cmd command.Command, prf []cid.Cid, opts ...Option) (
return &tkn, nil
}
type DelegationLoader interface {
GetDelegation(cid cid.Cid) (*delegation.Token, error)
}
func (t *Token) ExecutionAllowed(loader DelegationLoader) (bool, error) {
return t.executionAllowed(loader, t.arguments)
}
@@ -153,59 +150,21 @@ func (t *Token) ExecutionAllowedWithArgsHook(loader DelegationLoader, hook func(
}
func (t *Token) executionAllowed(loader DelegationLoader, arguments *args.Args) (bool, error) {
// There must be at least one delegation referenced - 4a
if len(t.proof) < 1 {
return false, ErrNoProof
delegations, err := t.loadProofs(loader)
if err != nil {
return false, err
}
type chainer interface {
Issuer() did.DID
Subject() did.DID // TODO: if the invocation token's Audience is nil, copy the subject into it
Command() command.Command
if err := t.verifyProofs(delegations); err != nil {
return false, err
}
// This starts as the invocation token but will be the root delegation
// after the for loop below completes
var lastChainer chainer = t
for i, dlgCid := range t.proof {
// The token must be present - 4b
dlg, err := loader.GetDelegation(dlgCid)
if err != nil {
return false, fmt.Errorf("%w: need %s", ErrMissingDelegation, dlgCid)
}
// No tokens in the proof chain may be expired - 4d
if dlg.Expiration() != nil && dlg.Expiration().Before(time.Now()) {
return false, fmt.Errorf("%w: CID is %s", ErrDelegationExpired, dlgCid)
}
// No tokens in the proof chain may be inactive - 4e
if dlg.NotBefore() != nil && dlg.NotBefore().After(time.Now()) {
return false, fmt.Errorf("%w: CID is %s", ErrDelegationInactive, dlgCid)
}
// First proof must have the invoker's Issuer as the Audience - 4c
if i == 0 && dlg.Audience() != t.Issuer() {
return false, fmt.Errorf("%w: expected %s, got %s", ErrNotIssuedToInvoker, t.issuer, dlg.Audience())
}
// Tokens must form a chain with current issuer equal to the
// next audience - 4f
if lastChainer.Issuer() != dlg.Audience() {
return false, fmt.Errorf("%w: expected %s, got %s", ErrBrokenChain, lastChainer.Issuer(), dlg.Audience())
}
// TODO: Checking the subject consistency can happen here - 4h
// TODO: Checking the command equivalence or attenuation can happen here - 4i
lastChainer = dlg
if err := t.verifyTimeBound(delegations); err != nil {
return false, err
}
// The last prf value must be a root delegation (have the issuer field
// match the Subject field) - 4g
if lastChainer.Issuer() != lastChainer.Subject() {
return false, fmt.Errorf("%w: expected %s, got %s", ErrLastNotRoot, lastChainer.Subject(), lastChainer.Issuer())
if err := t.verifyArgs(delegations, arguments); err != nil {
return false, err
}
return true, nil
@@ -304,6 +263,17 @@ func (t *Token) validate() error {
return errs
}
func (t *Token) loadProofs(loader DelegationLoader) (res []*delegation.Token, err error) {
res = make([]*delegation.Token, len(t.proof))
for i, c := range t.proof {
res[i], err = loader.GetDelegation(c)
if err != nil {
return nil, fmt.Errorf("%w: need %s", ErrMissingDelegation, c)
}
}
return res, nil
}
// tokenFromModel build a decoded view of the raw IPLD data.
// This function also serves as validation.
func tokenFromModel(m tokenPayloadModel) (*Token, error) {