open-consul/agent/acl.go

343 lines
10 KiB
Go

package agent
import (
"fmt"
"github.com/hashicorp/consul/acl"
"github.com/hashicorp/consul/agent/structs"
"github.com/hashicorp/serf/serf"
)
// resolveToken is the primary interface used by ACL-checkers in the agent
// endpoints, which is the one place where we do some ACL enforcement on
// clients. Some of the enforcement is normative (e.g. self and monitor)
// and some is informative (e.g. catalog and health).
func (a *Agent) resolveToken(id string) (acl.Authorizer, error) {
return a.resolveTokenAndDefaultMeta(id, nil, nil)
}
// resolveTokenAndDefaultMeta is used to resolve an ACL token secret to an
// acl.Authorizer and to default any enterprise specific metadata for the request.
// The defaulted metadata is then used to fill in an acl.AuthorizationContext.
func (a *Agent) resolveTokenAndDefaultMeta(id string, entMeta *structs.EnterpriseMeta, authzContext *acl.AuthorizerContext) (acl.Authorizer, error) {
// ACLs are disabled
if !a.delegate.ACLsEnabled() {
return nil, nil
}
if acl.RootAuthorizer(id) != nil {
return nil, acl.ErrRootDenied
}
if a.tokens.IsAgentMasterToken(id) {
return a.aclMasterAuthorizer, nil
}
return a.delegate.ResolveTokenAndDefaultMeta(id, entMeta, authzContext)
}
// resolveIdentityFromToken is used to resolve an ACLToken's secretID to a structs.ACLIdentity
func (a *Agent) resolveIdentityFromToken(secretID string) (structs.ACLIdentity, error) {
return a.delegate.ResolveTokenToIdentity(secretID)
}
// aclAccessorID is used to convert an ACLToken's secretID to its accessorID for non-
// critical purposes, such as logging. Therefore we interpret all errors as empty-string
// so we can safely log it without handling non-critical errors at the usage site.
func (a *Agent) aclAccessorID(secretID string) string {
ident, err := a.resolveIdentityFromToken(secretID)
if acl.IsErrNotFound(err) {
return ""
}
if err != nil {
a.logger.Debug("non-critical error resolving acl token accessor for logging", "error", err)
return ""
}
if ident == nil {
return ""
}
return ident.ID()
}
func (a *Agent) initializeACLs() error {
// Build a policy for the agent master token.
// The builtin agent master policy allows reading any node information
// and allows writes to the agent with the node name of the running agent
// only. This used to allow a prefix match on agent names but that seems
// entirely unnecessary so it is now using an exact match.
policy := &acl.Policy{
PolicyRules: acl.PolicyRules{
Agents: []*acl.AgentRule{
{
Node: a.config.NodeName,
Policy: acl.PolicyWrite,
},
},
NodePrefixes: []*acl.NodeRule{
{
Name: "",
Policy: acl.PolicyRead,
},
},
},
}
master, err := acl.NewPolicyAuthorizerWithDefaults(acl.DenyAll(), []*acl.Policy{policy}, nil)
if err != nil {
return err
}
a.aclMasterAuthorizer = master
return nil
}
// vetServiceRegister makes sure the service registration action is allowed by
// the given token.
func (a *Agent) vetServiceRegister(token string, service *structs.NodeService) error {
// Resolve the token and bail if ACLs aren't enabled.
authz, err := a.resolveToken(token)
if err != nil {
return err
}
return a.vetServiceRegisterWithAuthorizer(authz, service)
}
func (a *Agent) vetServiceRegisterWithAuthorizer(authz acl.Authorizer, service *structs.NodeService) error {
if authz == nil {
return nil
}
var authzContext acl.AuthorizerContext
service.FillAuthzContext(&authzContext)
// Vet the service itself.
if authz.ServiceWrite(service.Service, &authzContext) != acl.Allow {
return acl.ErrPermissionDenied
}
// Vet any service that might be getting overwritten.
if existing := a.State.Service(service.CompoundServiceID()); existing != nil {
existing.FillAuthzContext(&authzContext)
if authz.ServiceWrite(existing.Service, &authzContext) != acl.Allow {
return acl.ErrPermissionDenied
}
}
// If the service is a proxy, ensure that it has write on the destination too
// since it can be discovered as an instance of that service.
if service.Kind == structs.ServiceKindConnectProxy {
service.FillAuthzContext(&authzContext)
if authz.ServiceWrite(service.Proxy.DestinationServiceName, &authzContext) != acl.Allow {
return acl.ErrPermissionDenied
}
}
return nil
}
// vetServiceUpdate makes sure the service update action is allowed by the given
// token.
func (a *Agent) vetServiceUpdate(token string, serviceID structs.ServiceID) error {
// Resolve the token and bail if ACLs aren't enabled.
authz, err := a.resolveToken(token)
if err != nil {
return err
}
return a.vetServiceUpdateWithAuthorizer(authz, serviceID)
}
func (a *Agent) vetServiceUpdateWithAuthorizer(authz acl.Authorizer, serviceID structs.ServiceID) error {
if authz == nil {
return nil
}
var authzContext acl.AuthorizerContext
// Vet any changes based on the existing services's info.
if existing := a.State.Service(serviceID); existing != nil {
existing.FillAuthzContext(&authzContext)
if authz.ServiceWrite(existing.Service, &authzContext) != acl.Allow {
return acl.ErrPermissionDenied
}
} else {
return fmt.Errorf("Unknown service %q", serviceID)
}
return nil
}
// vetCheckRegister makes sure the check registration action is allowed by the
// given token.
func (a *Agent) vetCheckRegister(token string, check *structs.HealthCheck) error {
// Resolve the token and bail if ACLs aren't enabled.
authz, err := a.resolveToken(token)
if err != nil {
return err
}
return a.vetCheckRegisterWithAuthorizer(authz, check)
}
func (a *Agent) vetCheckRegisterWithAuthorizer(authz acl.Authorizer, check *structs.HealthCheck) error {
if authz == nil {
return nil
}
var authzContext acl.AuthorizerContext
check.FillAuthzContext(&authzContext)
// Vet the check itself.
if len(check.ServiceName) > 0 {
if authz.ServiceWrite(check.ServiceName, &authzContext) != acl.Allow {
return acl.PermissionDenied("Missing service:write on %v", structs.ServiceIDString(check.ServiceName, &check.EnterpriseMeta))
}
} else {
if authz.NodeWrite(a.config.NodeName, &authzContext) != acl.Allow {
return acl.PermissionDenied("Missing node:write on %s", a.config.NodeName)
}
}
// Vet any check that might be getting overwritten.
if existing := a.State.Check(check.CompoundCheckID()); existing != nil {
if len(existing.ServiceName) > 0 {
if authz.ServiceWrite(existing.ServiceName, &authzContext) != acl.Allow {
return acl.PermissionDenied("Missing service:write on %s", structs.ServiceIDString(existing.ServiceName, &existing.EnterpriseMeta))
}
} else {
if authz.NodeWrite(a.config.NodeName, &authzContext) != acl.Allow {
return acl.PermissionDenied("Missing node:write on %s", a.config.NodeName)
}
}
}
return nil
}
// vetCheckUpdate makes sure that a check update is allowed by the given token.
func (a *Agent) vetCheckUpdate(token string, checkID structs.CheckID) error {
// Resolve the token and bail if ACLs aren't enabled.
authz, err := a.resolveToken(token)
if err != nil {
return err
}
return a.vetCheckUpdateWithAuthorizer(authz, checkID)
}
func (a *Agent) vetCheckUpdateWithAuthorizer(authz acl.Authorizer, checkID structs.CheckID) error {
if authz == nil {
return nil
}
var authzContext acl.AuthorizerContext
checkID.FillAuthzContext(&authzContext)
// Vet any changes based on the existing check's info.
if existing := a.State.Check(checkID); existing != nil {
if len(existing.ServiceName) > 0 {
if authz.ServiceWrite(existing.ServiceName, &authzContext) != acl.Allow {
return acl.ErrPermissionDenied
}
} else {
if authz.NodeWrite(a.config.NodeName, &authzContext) != acl.Allow {
return acl.ErrPermissionDenied
}
}
} else {
return fmt.Errorf("Unknown check %q", checkID.String())
}
return nil
}
// filterMembers redacts members that the token doesn't have access to.
func (a *Agent) filterMembers(token string, members *[]serf.Member) error {
// Resolve the token and bail if ACLs aren't enabled.
rule, err := a.resolveToken(token)
if err != nil {
return err
}
if rule == nil {
return nil
}
var authzContext acl.AuthorizerContext
structs.DefaultEnterpriseMeta().FillAuthzContext(&authzContext)
// Filter out members based on the node policy.
m := *members
for i := 0; i < len(m); i++ {
node := m[i].Name
if rule.NodeRead(node, &authzContext) == acl.Allow {
continue
}
accessorID := a.aclAccessorID(token)
a.logger.Debug("dropping node from result due to ACLs", "node", node, "accessorID", accessorID)
m = append(m[:i], m[i+1:]...)
i--
}
*members = m
return nil
}
// filterServices redacts services that the token doesn't have access to.
func (a *Agent) filterServices(token string, services *map[structs.ServiceID]*structs.NodeService) error {
// Resolve the token and bail if ACLs aren't enabled.
authz, err := a.resolveToken(token)
if err != nil {
return err
}
return a.filterServicesWithAuthorizer(authz, services)
}
func (a *Agent) filterServicesWithAuthorizer(authz acl.Authorizer, services *map[structs.ServiceID]*structs.NodeService) error {
if authz == nil {
return nil
}
var authzContext acl.AuthorizerContext
// Filter out services based on the service policy.
for id, service := range *services {
service.FillAuthzContext(&authzContext)
if authz.ServiceRead(service.Service, &authzContext) == acl.Allow {
continue
}
a.logger.Debug("dropping service from result due to ACLs", "service", id.String())
delete(*services, id)
}
return nil
}
// filterChecks redacts checks that the token doesn't have access to.
func (a *Agent) filterChecks(token string, checks *map[structs.CheckID]*structs.HealthCheck) error {
// Resolve the token and bail if ACLs aren't enabled.
authz, err := a.resolveToken(token)
if err != nil {
return err
}
return a.filterChecksWithAuthorizer(authz, checks)
}
func (a *Agent) filterChecksWithAuthorizer(authz acl.Authorizer, checks *map[structs.CheckID]*structs.HealthCheck) error {
if authz == nil {
return nil
}
var authzContext acl.AuthorizerContext
// Filter out checks based on the node or service policy.
for id, check := range *checks {
if len(check.ServiceName) > 0 {
check.FillAuthzContext(&authzContext)
if authz.ServiceRead(check.ServiceName, &authzContext) == acl.Allow {
continue
}
} else {
structs.DefaultEnterpriseMeta().FillAuthzContext(&authzContext)
if authz.NodeRead(a.config.NodeName, &authzContext) == acl.Allow {
continue
}
}
a.logger.Debug("dropping check from result due to ACLs", "check", id.String())
delete(*checks, id)
}
return nil
}