initial commit to support go templates in policies

vault/policy.go

@@ -221,15 +221,20 @@ 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, 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, entity *identity.Entity, groups []*identity.Group) (*Policy, error) {
 	// Parse the rules
+	rules, templated, err := renderPolicy(rules, entity, groups)
+	if err != nil {
+		return nil, errwrap.Wrapf("failed to render templated policy: {{err}}", err)
+	}
+
 	root, err := hcl.Parse(rules)
 	if err != nil {
 		return nil, errwrap.Wrapf("failed to parse policy: {{err}}", err)
@@ -255,51 +260,31 @@ func parseACLPolicyWithTemplating(ns *namespace.Namespace, rules string, perform
 		Raw:       rules,
 		Type:      PolicyTypeACL,
 		namespace: ns,
+		Templated: templated,
 	}
 	if err := hcl.DecodeObject(&p, list); err != nil {
 		return nil, errwrap.Wrapf("failed to parse policy: {{err}}", err)
 	}
 
 	if o := list.Filter("path"); len(o.Items) > 0 {
-		if err := parsePaths(&p, o, performTemplating, entity, groups); err != nil {
+		if err := parsePaths(&p, o, entity, groups); err != nil {
 			return nil, errwrap.Wrapf("failed to parse policy: {{err}}", 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, entity *identity.Entity, groups []*identity.Group) error {
 	paths := make([]*PathRules, 0, len(list.Items))
 	for _, item := range list.Items {
 		key := "path"
 		if len(item.Keys) > 0 {
 			key = item.Keys[0].Token.Value().(string)
 		}
 
-		// Check the path
-		if performTemplating {
-			_, templated, err := identity.PopulateString(&identity.PopulateStringInput{
-				String:    key,
-				Entity:    entity,
-				Groups:    groups,
-				Namespace: result.namespace,
-			})
-			if err != nil {
-				continue
-			}
-			key = templated
-		} else {
-			hasTemplating, _, err := identity.PopulateString(&identity.PopulateStringInput{
-				ValidityCheckOnly: true,
-				String:            key,
-			})
-			if err != nil {
-				return errwrap.Wrapf("failed to validate policy templating: {{err}}", err)
-			}
-			if hasTemplating {
-				result.Templated = true
-			}
+		if strings.Contains(key, "<no_value>") {
+			continue
 		}
 
 		valid := []string{

vault/policy_store.go

@@ -774,7 +774,7 @@ 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, entity, groups)
 			if err != nil {
 				return nil, errwrap.Wrapf(fmt.Sprintf("error parsing templated policy %q: {{err}}", policy.Name), err)
 			}

vault/policy_templating.go

@@ -0,0 +1,115 @@
+package vault
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"strings"
+	"text/template"
+
+	"github.com/hashicorp/errwrap"
+	"github.com/hashicorp/vault/helper/identity"
+)
+
+var templateStaticFuncs = map[string]interface{}{
+	"replace":    strings.Replace,
+	"has_prefix": strings.HasPrefix,
+	"has_suffix": strings.HasSuffix,
+	"contains":   strings.Contains,
+}
+
+var templateFuncFactories = map[string]func(ctx context.Context) interface{}{
+	"identity": identityFuncFactory,
+}
+
+type policyTemplateContextKeys int
+
+const (
+	entityContextKey policyTemplateContextKeys = iota
+	groupsContextKey
+)
+
+func templateFuncs(ctx context.Context) template.FuncMap {
+	m := make(map[string]interface{}, len(templateFuncFactories)+len(templateStaticFuncs))
+	for key, f := range templateStaticFuncs {
+		m[key] = f
+	}
+	for key, f := range templateFuncFactories {
+		m[key] = f(ctx)
+	}
+	return m
+}
+
+func identityFuncFactory(ctx context.Context) interface{} {
+	entity, ok := ctx.Value(entityContextKey).(*identity.Entity)
+	if !ok {
+		entity = nil
+	}
+	groups, ok := ctx.Value(groupsContextKey).([]*identity.Group)
+	if !ok {
+		groups = nil
+	}
+	groupsMap := map[string]map[string]interface{}{}
+	var entityMap map[string]interface{}
+	var aliasMap map[string]map[string]interface{}
+	if entity != nil {
+		aliasMap = make(map[string]map[string]interface{}, len(entity.Aliases))
+		for _, alias := range entity.Aliases {
+			aliasMap[alias.MountAccessor] = map[string]interface{}{
+				"id":       alias.ID,
+				"name":     alias.Name,
+				"metadata": alias.Metadata,
+			}
+		}
+		entityMap = map[string]interface{}{
+			"name":     entity.Name,
+			"id":       entity.ID,
+			"metadata": entity.Metadata,
+			"aliases":  aliasMap,
+		}
+	}
+	if groups != nil {
+		groupsMap["ids"] = make(map[string]interface{}, len(groups))
+		groupsMap["names"] = make(map[string]interface{}, len(groups))
+		for _, group := range groups {
+			groupMap := map[string]interface{}{
+				"id":       group.ID,
+				"name":     group.Name,
+				"metadata": group.Metadata,
+			}
+			groupsMap["ids"][group.ID] = groupMap
+			groupsMap["names"][group.Name] = groupMap
+
+		}
+	}
+	identityMap := map[string]interface{}{
+		"entity": entityMap,
+		"groups": groupsMap,
+	}
+	return func() interface{} { return identityMap }
+}
+
+func renderPolicy(rules string, entity *identity.Entity, groups []*identity.Group) (string, bool, error) {
+	var tpl *template.Template
+	var err error
+	defer func() {
+		if r := recover(); r != nil {
+			err = fmt.Errorf("use of invalid keyword leads to panic, check your policy")
+		}
+	}()
+
+	ctx := context.Background()
+	ctx = context.WithValue(ctx, entityContextKey, entity)
+	ctx = context.WithValue(ctx, groupsContextKey, groups)
+	tpl, err = template.New("").Funcs(templateFuncs(ctx)).Parse(rules)
+	if err != nil {
+		return "", false, errwrap.Wrapf("failed to template policy: {{err}}", err)
+	}
+	buf := &bytes.Buffer{}
+	if err := tpl.Execute(buf, nil); err != nil {
+		return "", false, errwrap.Wrapf("failed to execute the template: {{err}}", err)
+	}
+
+	retStr := buf.String()
+	return retStr, len(retStr) != len(rules), err
+}