Support token's metadata in template

changelog/10682.txt

@@ -0,0 +1,3 @@
+```release-note:improvement
+core: support token metadata in template
+```

sdk/helper/identitytpl/templating.go

@@ -14,6 +14,7 @@ import (
 
 var (
 	ErrUnbalancedTemplatingCharacter = errors.New("unbalanced templating characters")
+	ErrNoAttachedToken               = errors.New("string contains entity template directives but no token was provided")
 	ErrNoEntityAttachedToToken       = errors.New("string contains entity template directives but no entity was provided")
 	ErrNoGroupsAttachedToToken       = errors.New("string contains groups template directives but no groups were provided")
 	ErrTemplateValueNotFound         = errors.New("no value could be found for one of the template directives")
@@ -27,6 +28,7 @@ const (
 type PopulateStringInput struct {
 	String            string
 	ValidityCheckOnly bool
+	Token             *logical.TokenEntry
 	Entity            *logical.Entity
 	Groups            []*logical.Group
 	NamespaceID       string
@@ -192,6 +194,18 @@ func performTemplating(input string, p *PopulateStringInput) (string, error) {
 		return "", ErrTemplateValueNotFound
 	}
 
+	performTokenTemplating := func(trimmed string) (string, error) {
+		switch {
+		case trimmed == "metadata":
+			return p.templateHandler(p.Token.Meta)
+		case strings.HasPrefix(trimmed, "metadata."):
+			split := strings.SplitN(trimmed, ".", 2)
+			return p.templateHandler(p.Token.Meta, split[1])
+		}
+
+		return "", ErrTemplateValueNotFound
+	}
+
 	performEntityTemplating := func(trimmed string) (string, error) {
 		switch {
 		case trimmed == "id":
@@ -352,6 +366,13 @@ func performTemplating(input string, p *PopulateStringInput) (string, error) {
 		}
 		return performEntityTemplating(strings.TrimPrefix(input, "identity.entity."))
 
+	case strings.HasPrefix(input, "token."):
+		if p.Token == nil {
+			return "", ErrNoAttachedToken
+		}
+
+		return performTokenTemplating(strings.TrimPrefix(input, "token."))
+
 	case strings.HasPrefix(input, "identity.groups."):
 		if len(p.Groups) == 0 {
 			return "", ErrNoGroupsAttachedToToken

sdk/helper/identitytpl/templating_test.go

@@ -553,3 +553,41 @@ func TestPopulate_FullObject(t *testing.T) {
 		t.Fatalf("expected:\n%s\n\ngot:\n%s", expected, out)
 	}
 }
+
+func TestPopulate_TokenMetaData(t *testing.T) {
+	testToken := &logical.TokenEntry{
+		Meta: map[string]string{
+			"color":         "green",
+			"size":          "small",
+			"non-printable": "\"\n\t",
+		},
+	}
+
+	template := `
+			{
+			    "all metadata": {{token.metadata}},
+			    "one metadata key": {{token.metadata.color}},
+			    "one metadata key not found": {{token.metadata.asldfk}}
+			}`
+
+	expected := `
+			{
+			    "all metadata": {"color":"green","non-printable":"\"\n\t","size":"small"},
+			    "one metadata key": "green",
+			    "one metadata key not found": ""
+			}`
+
+	input := PopulateStringInput{
+		Mode:   JSONTemplating,
+		String: template,
+		Token:  testToken,
+	}
+	_, out, err := PopulateString(input)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if out != expected {
+		t.Fatalf("expected:\n%s\n\ngot:\n%s", expected, out)
+	}
+}

vault/capabilities.go

@@ -19,7 +19,7 @@ func (c *Core) Capabilities(ctx context.Context, token, path string) ([]string,
 		return nil, &logical.StatusBadRequest{Err: "missing token"}
 	}
 
-	te, err := c.tokenStore.Lookup(ctx, token)
+	te, err := c.LookupToken(ctx, token)
 	if err != nil {
 		return nil, err
 	}
@@ -76,7 +76,7 @@ func (c *Core) Capabilities(ctx context.Context, token, path string) ([]string,
 	// Construct the corresponding ACL object. ACL construction should be
 	// performed on the token's namespace.
 	tokenCtx := namespace.ContextWithNamespace(ctx, tokenNS)
-	acl, err := c.policyStore.ACL(tokenCtx, entity, policyNames, policies...)
+	acl, err := c.policyStore.ACL(tokenCtx, entity, te, policyNames, policies...)
 	if err != nil {
 		return nil, err
 	}

vault/dynamic_system_view.go

@@ -114,7 +114,7 @@ func (e extendedSystemViewImpl) SudoPrivilege(ctx context.Context, path string,
 
 	// Construct the corresponding ACL object. Derive and use a new context that
 	// uses the req.ClientToken's namespace
-	acl, err := e.core.policyStore.ACL(tokenCtx, entity, policyNames, policies...)
+	acl, err := e.core.policyStore.ACL(tokenCtx, entity, te, policyNames, policies...)
 	if err != nil {
 		e.core.logger.Error("failed to retrieve ACL for token's policies", "token_policies", te.Policies, "error", err)
 		return false

vault/policy.go

@@ -14,6 +14,7 @@ import (
 	"github.com/hashicorp/vault/helper/namespace"
 	"github.com/hashicorp/vault/sdk/helper/hclutil"
 	"github.com/hashicorp/vault/sdk/helper/identitytpl"
+	"github.com/hashicorp/vault/sdk/logical"
 	"github.com/mitchellh/copystructure"
 )
 
@@ -232,14 +233,14 @@ func (p *ACLPermissions) Clone() (*ACLPermissions, error) {
 // intermediary set of policies, before being compiled into
 // the ACL
 func ParseACLPolicy(ns *namespace.Namespace, rules string) (*Policy, error) {
-	return parseACLPolicyWithTemplating(ns, rules, false, nil, nil)
+	return parseACLPolicyWithTemplating(ns, rules, false, nil, nil, nil)
 }
 
 // parseACLPolicyWithTemplating performs the actual work and checks whether we
 // should perform substitutions. If performTemplating is true we know that it
 // is templated so we don't check again, otherwise we check to see if it's a
 // templated policy.
-func parseACLPolicyWithTemplating(ns *namespace.Namespace, rules string, performTemplating bool, entity *identity.Entity, groups []*identity.Group) (*Policy, error) {
+func parseACLPolicyWithTemplating(ns *namespace.Namespace, rules string, performTemplating bool, entity *identity.Entity, groups []*identity.Group, token *logical.TokenEntry) (*Policy, error) {
 	// Parse the rules
 	root, err := hcl.Parse(rules)
 	if err != nil {
@@ -272,15 +273,15 @@ func parseACLPolicyWithTemplating(ns *namespace.Namespace, rules string, perform
 	}
 
 	if o := list.Filter("path"); len(o.Items) > 0 {
-		if err := parsePaths(&p, o, performTemplating, entity, groups); err != nil {
+		if err := parsePaths(&p, o, performTemplating, entity, groups, token); err != nil {
 			return nil, fmt.Errorf("failed to parse policy: %w", err)
 		}
 	}
 
 	return &p, nil
 }
 
-func parsePaths(result *Policy, list *ast.ObjectList, performTemplating bool, entity *identity.Entity, groups []*identity.Group) error {
+func parsePaths(result *Policy, list *ast.ObjectList, performTemplating bool, entity *identity.Entity, groups []*identity.Group, token *logical.TokenEntry) error {
 	paths := make([]*PathRules, 0, len(list.Items))
 	for _, item := range list.Items {
 		key := "path"
@@ -293,6 +294,7 @@ func parsePaths(result *Policy, list *ast.ObjectList, performTemplating bool, en
 			_, templated, err := identitytpl.PopulateString(identitytpl.PopulateStringInput{
 				Mode:        identitytpl.ACLTemplating,
 				String:      key,
+				Token:       token,
 				Entity:      identity.ToSDKEntity(entity),
 				Groups:      identity.ToSDKGroups(groups),
 				NamespaceID: result.namespace.ID,

vault/policy_store.go

@@ -754,7 +754,7 @@ func (t *TemplateError) Error() string {
 
 // ACL is used to return an ACL which is built using the
 // named policies and pre-fetched policies if given.
-func (ps *PolicyStore) ACL(ctx context.Context, entity *identity.Entity, policyNames map[string][]string, additionalPolicies ...*Policy) (*ACL, error) {
+func (ps *PolicyStore) ACL(ctx context.Context, entity *identity.Entity, token *logical.TokenEntry, policyNames map[string][]string, additionalPolicies ...*Policy) (*ACL, error) {
 	var allPolicies []*Policy
 
 	// Fetch the named policies
@@ -795,7 +795,7 @@ func (ps *PolicyStore) ACL(ctx context.Context, entity *identity.Entity, policyN
 					groups = append(directGroups, inheritedGroups...)
 				}
 			}
-			p, err := parseACLPolicyWithTemplating(policy.namespace, policy.Raw, true, entity, groups)
+			p, err := parseACLPolicyWithTemplating(policy.namespace, policy.Raw, true, entity, groups, token)
 			if err != nil {
 				return nil, fmt.Errorf("error parsing templated policy %q: %w", policy.Name, err)
 			}

vault/policy_store_test.go

@@ -268,7 +268,7 @@ func testPolicyStoreACL(t *testing.T, ps *PolicyStore, ns *namespace.Namespace)
 	}
 
 	ctx = namespace.ContextWithNamespace(context.Background(), ns)
-	acl, err := ps.ACL(ctx, nil, map[string][]string{ns.ID: {"dev", "ops"}})
+	acl, err := ps.ACL(ctx, nil, nil, map[string][]string{ns.ID: {"dev", "ops"}})
 	if err != nil {
 		t.Fatalf("err: %v", err)
 	}

vault/request_handling.go

@@ -229,7 +229,7 @@ func (c *Core) fetchACLTokenEntryAndEntity(ctx context.Context, req *logical.Req
 
 	// Construct the corresponding ACL object. ACL construction should be
 	// performed on the token's namespace.
-	acl, err := c.policyStore.ACL(tokenCtx, entity, policyNames, policies...)
+	acl, err := c.policyStore.ACL(tokenCtx, entity, te, policyNames, policies...)
 	if err != nil {
 		if errwrap.ContainsType(err, new(TemplateError)) {
 			c.logger.Warn("permission denied due to a templated policy being invalid or containing directives not satisfied by the requestor", "error", err)

website/content/docs/concepts/policies.mdx

@@ -258,6 +258,7 @@ injected, and currently the `path` keys in policies allow injection.
 
 | Name                                                                             | Description                                                                            |
 | :------------------------------------------------------------------------------- | :------------------------------------------------------------------------------------- |
+| `token.metadata.<metadata key>`                                                  | The token's associated metadata                                                        |
 | `identity.entity.id`                                                             | The entity's ID                                                                        |
 | `identity.entity.name`                                                           | The entity's name                                                                      |
 | `identity.entity.metadata.<metadata key>`                                        | Metadata associated with the entity for the given key                                  |