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delegation: tune the validation step

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- avoid a double parsing when the flow already parsed (command, policy)
- don't require a did:key, as other types are legal (but might require a resolver, TODO)
- make the command a struct instead of a pointer: we don't need to avoid copy, and the pointer can be interpreted as nil
- make the nonce parameter optional, but generate one if none is given
This commit is contained in:
Michael Muré
2024-09-19 11:16:33 +02:00
parent 4749243e3c
commit 684c21c7a4
4 changed files with 60 additions and 39 deletions
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34
capability/command/command.go
View File

@@ -20,11 +20,10 @@ type Command struct {
segments []string
}
// New creates a validated command from the provided list of segment
// strings. An error is returned if an invalid Command would be
// formed
func New(segments ...string) *Command {
return &Command{segments: segments}
// New creates a validated command from the provided list of segment strings.
// An error is returned if an invalid Command would be formed
func New(segments ...string) Command {
return Command{segments: segments}
}
// Parse verifies that the provided string contains the required
@@ -32,26 +31,26 @@ func New(segments ...string) *Command {
// Command.
//
// [segment structure]: https://github.com/ucan-wg/spec#segment-structure
func Parse(s string) (*Command, error) {
func Parse(s string) (Command, error) {
if !strings.HasPrefix(s, "/") {
return nil, ErrRequiresLeadingSlash
return Command{}, ErrRequiresLeadingSlash
}
if len(s) > 1 && strings.HasSuffix(s, "/") {
return nil, ErrDisallowsTrailingSlash
return Command{}, ErrDisallowsTrailingSlash
}
if s != strings.ToLower(s) {
return nil, ErrRequiresLowercase
return Command{}, ErrRequiresLowercase
}
// The leading slash will result in the first element from strings.Split
// being an empty string which is removed as strings.Join will ignore it.
return &Command{strings.Split(s, "/")[1:]}, nil
return Command{strings.Split(s, "/")[1:]}, nil
}
// MustParse is the same as Parse, but panic() if the parsing fail.
func MustParse(s string) *Command {
func MustParse(s string) Command {
c, err := Parse(s)
if err != nil {
panic(err)
@@ -62,11 +61,10 @@ func MustParse(s string) *Command {
// [Top] is the most powerful capability.
//
// This function returns a Command that is a wildcard and therefore represents the
// most powerful abilily. As such it should be handle with care and used
// sparingly.
// most powerful ability. As such, it should be handled with care and used sparingly.
//
// [Top]: https://github.com/ucan-wg/spec#-aka-top
func Top() *Command {
func Top() Command {
return New()
}
@@ -78,18 +76,18 @@ func IsValid(s string) bool {
// Join appends segments to the end of this command using the required
// segment separator.
func (c *Command) Join(segments ...string) *Command {
return &Command{append(c.segments, segments...)}
func (c Command) Join(segments ...string) Command {
return Command{append(c.segments, segments...)}
}
// Segments returns the ordered segments that comprise the Command as a
// slice of strings.
func (c *Command) Segments() []string {
func (c Command) Segments() []string {
return c.segments
}
// String returns the composed representation the command. This is also
// the required wire representation (before IPLD encoding occurs.)
func (c *Command) String() string {
func (c Command) String() string {
return "/" + strings.Join(c.segments, "/")
}

2
capability/command/command_test.go
View File

@@ -74,7 +74,7 @@ func TestParseCommand(t *testing.T) {
cmd, err := command.Parse(testcase.inp)
require.ErrorIs(t, err, testcase.err)
require.Nil(t, cmd)
require.Equal(t, command.Command{}, cmd)
})
}
})

54
delegation/delegation.go
View File

@@ -1,6 +1,7 @@
package delegation
import (
"crypto/rand"
"errors"
"fmt"
"time"
@@ -21,7 +22,7 @@ type Token struct {
// Principal that the chain is about (the Subject)
subject did.DID
// The Command to eventually invoke
command *command.Command
command command.Command
// The delegation policy
policy policy.Policy
// A unique, random nonce
@@ -35,7 +36,7 @@ type Token struct {
}
// New creates a validated Token from the provided parameters and options.
func New(privKey crypto.PrivKey, aud did.DID, cmd *command.Command, pol policy.Policy, nonce []byte, opts ...Option) (*Token, error) {
func New(privKey crypto.PrivKey, aud did.DID, cmd command.Command, pol policy.Policy, opts ...Option) (*Token, error) {
iss, err := did.FromPrivKey(privKey)
if err != nil {
return nil, err
@@ -48,7 +49,7 @@ func New(privKey crypto.PrivKey, aud did.DID, cmd *command.Command, pol policy.P
command: cmd,
policy: pol,
meta: meta.NewMeta(),
nonce: nonce,
nonce: nil,
}
for _, opt := range opts {
@@ -57,6 +58,13 @@ func New(privKey crypto.PrivKey, aud did.DID, cmd *command.Command, pol policy.P
}
}
if len(tkn.nonce) == 0 {
tkn.nonce, err = generateNonce()
if err != nil {
return nil, err
}
}
if err := tkn.validate(); err != nil {
return nil, err
}
@@ -64,7 +72,7 @@ func New(privKey crypto.PrivKey, aud did.DID, cmd *command.Command, pol policy.P
return tkn, nil
}
func Root(privKey crypto.PrivKey, aud did.DID, cmd *command.Command, pol policy.Policy, nonce []byte, opts ...Option) (*Token, error) {
func Root(privKey crypto.PrivKey, aud did.DID, cmd command.Command, pol policy.Policy, opts ...Option) (*Token, error) {
sub, err := did.FromPrivKey(privKey)
if err != nil {
return nil, err
@@ -72,7 +80,7 @@ func Root(privKey crypto.PrivKey, aud did.DID, cmd *command.Command, pol policy.
opts = append(opts, WithSubject(sub))
return New(privKey, aud, cmd, pol, nonce, opts...)
return New(privKey, aud, cmd, pol, opts...)
}
// Issuer returns the did.DID representing the Token's issuer.
@@ -95,7 +103,7 @@ func (t *Token) Subject() did.DID {
}
// Command returns the capability's command.Command.
func (t *Token) Command() *command.Command {
func (t *Token) Command() command.Command {
return t.command
}
@@ -128,23 +136,16 @@ func (t *Token) validate() error {
var errs error
requiredDID := func(id did.DID, fieldname string) {
if !id.Key() {
errs = errors.Join(errs, fmt.Errorf("a \"did:key\" is required for %s: %s", fieldname, id.String()))
if !id.Defined() {
errs = errors.Join(errs, fmt.Errorf(`a valid did is required for %s: %s`, fieldname, id.String()))
}
}
requiredDID(t.issuer, "Issuer")
requiredDID(t.audience, "Audience")
if t.subject != did.Undef {
requiredDID(t.subject, "Subject")
}
if _, err := command.Parse(t.command.String()); err != nil {
errs = errors.Join(errs, err)
}
if _, err := t.policy.ToIPLD(); err != nil {
errs = errors.Join(errs, err)
if len(t.nonce) < 12 {
errs = errors.Join(errs, fmt.Errorf("token nonce too small"))
}
return errs
@@ -205,6 +206,15 @@ func WithSubject(sub did.DID) Option {
}
}
// WithNonce sets the Token's nonce with the given value.
// If this option is not used, a random 12-byte nonce is generated for this required field.
func WithNonce(nonce []byte) Option {
return func(t *Token) error {
t.nonce = nonce
return nil
}
}
// tokenFromModel build a decoded view of the raw IPLD data.
// This function also serves as validation.
func tokenFromModel(m tokenPayloadModel) (*Token, error) {
@@ -265,3 +275,13 @@ func tokenFromModel(m tokenPayloadModel) (*Token, error) {
return &tkn, nil
}
// generateNonce creates a 12-byte random nonce.
func generateNonce() ([]byte, error) {
res := make([]byte, 12)
_, err := rand.Read(res)
if err != nil {
return nil, err
}
return res, nil
}

9
delegation/delegation_test.go
View File

@@ -86,7 +86,8 @@ func TestConstructors(t *testing.T) {
require.NoError(t, err)
t.Run("New", func(t *testing.T) {
dlg, err := delegation.New(privKey, aud, cmd, pol, []byte(nonce),
dlg, err := delegation.New(privKey, aud, cmd, pol,
delegation.WithNonce([]byte(nonce)),
delegation.WithSubject(sub),
delegation.WithExpiration(exp),
delegation.WithMeta("foo", "fooo"),
@@ -105,7 +106,8 @@ func TestConstructors(t *testing.T) {
t.Run("Root", func(t *testing.T) {
t.Parallel()
dlg, err := delegation.Root(privKey, aud, cmd, pol, []byte(nonce),
dlg, err := delegation.Root(privKey, aud, cmd, pol,
delegation.WithNonce([]byte(nonce)),
delegation.WithExpiration(exp),
delegation.WithMeta("foo", "fooo"),
delegation.WithMeta("bar", "barr"),
@@ -134,7 +136,8 @@ func privKey(t *testing.T, privKeyCfg string) crypto.PrivKey {
}
func TestKey(t *testing.T) {
t.Skip()
// TODO: why is this broken?
t.Skip("TODO: why is this broken?")
priv, _, err := crypto.GenerateEd25519Key(rand.Reader)
require.NoError(t, err)