open-consul/agent/consul/intention_endpoint.go
2021-05-06 13:30:07 -04:00

781 lines
24 KiB
Go

package consul
import (
"errors"
"fmt"
"time"
"github.com/armon/go-metrics"
"github.com/armon/go-metrics/prometheus"
"github.com/hashicorp/go-bexpr"
"github.com/hashicorp/go-hclog"
"github.com/hashicorp/go-memdb"
"github.com/hashicorp/consul/acl"
"github.com/hashicorp/consul/agent/consul/state"
"github.com/hashicorp/consul/agent/structs"
"github.com/hashicorp/consul/lib"
)
var IntentionSummaries = []prometheus.SummaryDefinition{
{
Name: []string{"consul", "intention", "apply"},
Help: "",
},
{
Name: []string{"intention", "apply"},
Help: "",
},
}
var (
// ErrIntentionNotFound is returned if the intention lookup failed.
ErrIntentionNotFound = errors.New("Intention not found")
)
// Intention manages the Connect intentions.
type Intention struct {
// srv is a pointer back to the server.
srv *Server
logger hclog.Logger
}
func (s *Intention) checkIntentionID(id string) (bool, error) {
state := s.srv.fsm.State()
if _, _, ixn, err := state.IntentionGet(nil, id); err != nil {
return false, err
} else if ixn != nil {
return false, nil
}
return true, nil
}
var ErrIntentionsNotUpgradedYet = errors.New("Intentions are read only while being upgraded to config entries")
// legacyUpgradeCheck fast fails a write request using the legacy intention
// RPCs if the system is known to be mid-upgrade. This is purely a perf
// optimization and the actual real enforcement happens in the FSM. It would be
// wasteful to round trip all the way through raft to have it fail for
// known-up-front reasons, hence why we check it twice.
func (s *Intention) legacyUpgradeCheck() error {
usingConfigEntries, err := s.srv.fsm.State().AreIntentionsInConfigEntries()
if err != nil {
return fmt.Errorf("system metadata lookup failed: %v", err)
}
if !usingConfigEntries {
return ErrIntentionsNotUpgradedYet
}
return nil
}
// Apply creates or updates an intention in the data store.
func (s *Intention) Apply(args *structs.IntentionRequest, reply *string) error {
// Exit early if Connect hasn't been enabled.
if !s.srv.config.ConnectEnabled {
return ErrConnectNotEnabled
}
// Ensure that all service-intentions config entry writes go to the primary
// datacenter. These will then be replicated to all the other datacenters.
args.Datacenter = s.srv.config.PrimaryDatacenter
if done, err := s.srv.ForwardRPC("Intention.Apply", args, reply); done {
return err
}
defer metrics.MeasureSince([]string{"consul", "intention", "apply"}, time.Now())
defer metrics.MeasureSince([]string{"intention", "apply"}, time.Now())
if err := s.legacyUpgradeCheck(); err != nil {
return err
}
if args.Mutation != nil {
return fmt.Errorf("Mutation field is internal only and must not be set via RPC")
}
// Always set a non-nil intention to avoid nil-access below
if args.Intention == nil {
args.Intention = &structs.Intention{}
}
// Get the ACL token for the request for the checks below.
var entMeta structs.EnterpriseMeta
ident, authz, err := s.srv.ResolveTokenIdentityAndDefaultMeta(args.Token, &entMeta, nil)
if err != nil {
return err
}
var accessorID string
if ident != nil {
accessorID = ident.ID()
}
var (
mut *structs.IntentionMutation
legacyWrite bool
)
switch args.Op {
case structs.IntentionOpCreate:
legacyWrite = true
mut, err = s.computeApplyChangesLegacyCreate(accessorID, authz, &entMeta, args)
case structs.IntentionOpUpdate:
legacyWrite = true
mut, err = s.computeApplyChangesLegacyUpdate(accessorID, authz, &entMeta, args)
case structs.IntentionOpUpsert:
legacyWrite = false
mut, err = s.computeApplyChangesUpsert(accessorID, authz, &entMeta, args)
case structs.IntentionOpDelete:
if args.Intention.ID == "" {
legacyWrite = false
mut, err = s.computeApplyChangesDelete(accessorID, authz, &entMeta, args)
} else {
legacyWrite = true
mut, err = s.computeApplyChangesLegacyDelete(accessorID, authz, &entMeta, args)
}
case structs.IntentionOpDeleteAll:
// This is an internal operation initiated by the leader and is not
// exposed for general RPC use.
return fmt.Errorf("Invalid Intention operation: %v", args.Op)
default:
return fmt.Errorf("Invalid Intention operation: %v", args.Op)
}
if err != nil {
return err
}
if mut == nil {
return nil // short circuit
}
if legacyWrite {
*reply = args.Intention.ID
} else {
*reply = ""
}
// Switch to the config entry manipulating flavor:
args.Mutation = mut
args.Intention = nil
_, err = s.srv.raftApply(structs.IntentionRequestType, args)
return err
}
func (s *Intention) computeApplyChangesLegacyCreate(
accessorID string,
authz acl.Authorizer,
entMeta *structs.EnterpriseMeta,
args *structs.IntentionRequest,
) (*structs.IntentionMutation, error) {
// This variant is just for legacy UUID-based intentions.
args.Intention.DefaultNamespaces(entMeta)
if !args.Intention.CanWrite(authz) {
sn := args.Intention.SourceServiceName()
dn := args.Intention.DestinationServiceName()
// todo(kit) Migrate intention access denial logging over to audit logging when we implement it
s.logger.Warn("Intention creation denied due to ACLs",
"source", sn.String(),
"destination", dn.String(),
"accessorID", accessorID)
return nil, acl.ErrPermissionDenied
}
// If no ID is provided, generate a new ID. This must be done prior to
// appending to the Raft log, because the ID is not deterministic. Once
// the entry is in the log, the state update MUST be deterministic or
// the followers will not converge.
if args.Intention.ID != "" {
return nil, fmt.Errorf("ID must be empty when creating a new intention")
}
var err error
args.Intention.ID, err = lib.GenerateUUID(s.checkIntentionID)
if err != nil {
return nil, err
}
// Set the created at
args.Intention.CreatedAt = time.Now().UTC()
args.Intention.UpdatedAt = args.Intention.CreatedAt
// Default source type
if args.Intention.SourceType == "" {
args.Intention.SourceType = structs.IntentionSourceConsul
}
if err := s.validateEnterpriseIntention(args.Intention); err != nil {
return nil, err
}
//nolint:staticcheck
if err := args.Intention.Validate(); err != nil {
return nil, err
}
// NOTE: if the append of this source causes a duplicate source name the
// config entry validation will fail so we don't have to check that
// explicitly here.
mut := &structs.IntentionMutation{
Destination: args.Intention.DestinationServiceName(),
Value: args.Intention.ToSourceIntention(true),
}
// Set the created/updated times. If this is an update instead of an insert
// the UpdateOver() will fix it up appropriately.
now := time.Now().UTC()
mut.Value.LegacyCreateTime = timePointer(now)
mut.Value.LegacyUpdateTime = timePointer(now)
return mut, nil
}
func (s *Intention) computeApplyChangesLegacyUpdate(
accessorID string,
authz acl.Authorizer,
entMeta *structs.EnterpriseMeta,
args *structs.IntentionRequest,
) (*structs.IntentionMutation, error) {
// This variant is just for legacy UUID-based intentions.
_, _, ixn, err := s.srv.fsm.State().IntentionGet(nil, args.Intention.ID)
if err != nil {
return nil, fmt.Errorf("Intention lookup failed: %v", err)
}
if ixn == nil {
return nil, fmt.Errorf("Cannot modify non-existent intention: '%s'", args.Intention.ID)
}
if !ixn.CanWrite(authz) {
// todo(kit) Migrate intention access denial logging over to audit logging when we implement it
s.logger.Warn("Update operation on intention denied due to ACLs", "intention", args.Intention.ID, "accessorID", accessorID)
return nil, acl.ErrPermissionDenied
}
args.Intention.DefaultNamespaces(entMeta)
// Prior to v1.9.0 renames of the destination side of an intention were
// allowed, but that behavior doesn't work anymore.
if ixn.DestinationServiceName() != args.Intention.DestinationServiceName() {
return nil, fmt.Errorf("Cannot modify DestinationNS or DestinationName for an intention once it exists.")
}
// Default source type
if args.Intention.SourceType == "" {
args.Intention.SourceType = structs.IntentionSourceConsul
}
if err := s.validateEnterpriseIntention(args.Intention); err != nil {
return nil, err
}
// Validate. We do not validate on delete since it is valid to only
// send an ID in that case.
//nolint:staticcheck
if err := args.Intention.Validate(); err != nil {
return nil, err
}
mut := &structs.IntentionMutation{
ID: args.Intention.ID,
Value: args.Intention.ToSourceIntention(true),
}
// Set the created/updated times. If this is an update instead of an insert
// the UpdateOver() will fix it up appropriately.
now := time.Now().UTC()
mut.Value.LegacyCreateTime = timePointer(now)
mut.Value.LegacyUpdateTime = timePointer(now)
return mut, nil
}
func (s *Intention) computeApplyChangesUpsert(
accessorID string,
authz acl.Authorizer,
entMeta *structs.EnterpriseMeta,
args *structs.IntentionRequest,
) (*structs.IntentionMutation, error) {
// This variant is just for config-entry based intentions.
if args.Intention.ID != "" {
// This is a new-style only endpoint
return nil, fmt.Errorf("ID must not be specified")
}
args.Intention.DefaultNamespaces(entMeta)
if !args.Intention.CanWrite(authz) {
sn := args.Intention.SourceServiceName()
dn := args.Intention.DestinationServiceName()
// todo(kit) Migrate intention access denial logging over to audit logging when we implement it
s.logger.Warn("Intention upsert denied due to ACLs",
"source", sn.String(),
"destination", dn.String(),
"accessorID", accessorID)
return nil, acl.ErrPermissionDenied
}
_, prevEntry, err := s.srv.fsm.State().ConfigEntry(nil, structs.ServiceIntentions, args.Intention.DestinationName, args.Intention.DestinationEnterpriseMeta())
if err != nil {
return nil, fmt.Errorf("Intention lookup failed: %v", err)
}
if prevEntry == nil {
// Meta is NOT permitted here, as it would need to be persisted on
// the enclosing config entry.
if len(args.Intention.Meta) > 0 {
return nil, fmt.Errorf("Meta must not be specified")
}
} else {
if len(args.Intention.Meta) > 0 {
// Meta is NOT permitted here, but there is one exception. If
// you are updating a previous record, but that record lives
// within a config entry that itself has Meta, then you may
// incidentally ship the Meta right back to consul.
//
// In that case if Meta is provided, it has to be a perfect
// match for what is already on the enclosing config entry so
// it's safe to discard.
if !equalStringMaps(prevEntry.GetMeta(), args.Intention.Meta) {
return nil, fmt.Errorf("Meta must not be specified, or should be unchanged during an update.")
}
// Now it is safe to discard
args.Intention.Meta = nil
}
}
return &structs.IntentionMutation{
Destination: args.Intention.DestinationServiceName(),
Source: args.Intention.SourceServiceName(),
Value: args.Intention.ToSourceIntention(false),
}, nil
}
func (s *Intention) computeApplyChangesLegacyDelete(
accessorID string,
authz acl.Authorizer,
entMeta *structs.EnterpriseMeta,
args *structs.IntentionRequest,
) (*structs.IntentionMutation, error) {
_, _, ixn, err := s.srv.fsm.State().IntentionGet(nil, args.Intention.ID)
if err != nil {
return nil, fmt.Errorf("Intention lookup failed: %v", err)
}
if ixn == nil {
return nil, fmt.Errorf("Cannot delete non-existent intention: '%s'", args.Intention.ID)
}
if !ixn.CanWrite(authz) {
// todo(kit) Migrate intention access denial logging over to audit logging when we implement it
s.logger.Warn("Deletion operation on intention denied due to ACLs", "intention", args.Intention.ID, "accessorID", accessorID)
return nil, acl.ErrPermissionDenied
}
return &structs.IntentionMutation{
ID: args.Intention.ID,
}, nil
}
func (s *Intention) computeApplyChangesDelete(
accessorID string,
authz acl.Authorizer,
entMeta *structs.EnterpriseMeta,
args *structs.IntentionRequest,
) (*structs.IntentionMutation, error) {
args.Intention.DefaultNamespaces(entMeta)
if !args.Intention.CanWrite(authz) {
sn := args.Intention.SourceServiceName()
dn := args.Intention.DestinationServiceName()
// todo(kit) Migrate intention access denial logging over to audit logging when we implement it
s.logger.Warn("Intention delete denied due to ACLs",
"source", sn.String(),
"destination", dn.String(),
"accessorID", accessorID)
return nil, acl.ErrPermissionDenied
}
// Pre-flight to avoid pointless raft operations.
exactIxn := args.Intention.ToExact()
_, _, ixn, err := s.srv.fsm.State().IntentionGetExact(nil, exactIxn)
if err != nil {
return nil, fmt.Errorf("Intention lookup failed: %v", err)
}
if ixn == nil {
return nil, nil // by-name deletions are idempotent
}
return &structs.IntentionMutation{
Destination: args.Intention.DestinationServiceName(),
Source: args.Intention.SourceServiceName(),
}, nil
}
// Get returns a single intention by ID.
func (s *Intention) Get(args *structs.IntentionQueryRequest, reply *structs.IndexedIntentions) error {
// Exit early if Connect hasn't been enabled.
if !s.srv.config.ConnectEnabled {
return ErrConnectNotEnabled
}
// Forward if necessary
if done, err := s.srv.ForwardRPC("Intention.Get", args, reply); done {
return err
}
// Get the ACL token for the request for the checks below.
var entMeta structs.EnterpriseMeta
if _, err := s.srv.ResolveTokenAndDefaultMeta(args.Token, &entMeta, nil); err != nil {
return err
}
if args.Exact != nil {
// // Finish defaulting the namespace fields.
if args.Exact.SourceNS == "" {
args.Exact.SourceNS = entMeta.NamespaceOrDefault()
}
if err := s.srv.validateEnterpriseIntentionNamespace(args.Exact.SourceNS, true); err != nil {
return fmt.Errorf("Invalid SourceNS %q: %v", args.Exact.SourceNS, err)
}
if args.Exact.DestinationNS == "" {
args.Exact.DestinationNS = entMeta.NamespaceOrDefault()
}
if err := s.srv.validateEnterpriseIntentionNamespace(args.Exact.DestinationNS, true); err != nil {
return fmt.Errorf("Invalid DestinationNS %q: %v", args.Exact.DestinationNS, err)
}
}
return s.srv.blockingQuery(
&args.QueryOptions,
&reply.QueryMeta,
func(ws memdb.WatchSet, state *state.Store) error {
var (
index uint64
ixn *structs.Intention
err error
)
if args.IntentionID != "" {
index, _, ixn, err = state.IntentionGet(ws, args.IntentionID)
} else if args.Exact != nil {
index, _, ixn, err = state.IntentionGetExact(ws, args.Exact)
}
if err != nil {
return err
}
if ixn == nil {
return ErrIntentionNotFound
}
reply.Index = index
reply.Intentions = structs.Intentions{ixn}
// Filter
if err := s.srv.filterACL(args.Token, reply); err != nil {
return err
}
// If ACLs prevented any responses, error
if len(reply.Intentions) == 0 {
accessorID := s.aclAccessorID(args.Token)
// todo(kit) Migrate intention access denial logging over to audit logging when we implement it
s.logger.Warn("Request to get intention denied due to ACLs", "intention", args.IntentionID, "accessorID", accessorID)
return acl.ErrPermissionDenied
}
return nil
},
)
}
// List returns all the intentions.
func (s *Intention) List(args *structs.IntentionListRequest, reply *structs.IndexedIntentions) error {
// Exit early if Connect hasn't been enabled.
if !s.srv.config.ConnectEnabled {
return ErrConnectNotEnabled
}
// Forward if necessary
if done, err := s.srv.ForwardRPC("Intention.List", args, reply); done {
return err
}
filter, err := bexpr.CreateFilter(args.Filter, nil, reply.Intentions)
if err != nil {
return err
}
var authzContext acl.AuthorizerContext
if _, err := s.srv.ResolveTokenAndDefaultMeta(args.Token, &args.EnterpriseMeta, &authzContext); err != nil {
return err
}
if err := s.srv.validateEnterpriseRequest(&args.EnterpriseMeta, false); err != nil {
return err
}
return s.srv.blockingQuery(
&args.QueryOptions, &reply.QueryMeta,
func(ws memdb.WatchSet, state *state.Store) error {
var (
index uint64
ixns structs.Intentions
fromConfig bool
err error
)
if args.Legacy {
index, ixns, err = state.LegacyIntentions(ws, &args.EnterpriseMeta)
} else {
index, ixns, fromConfig, err = state.Intentions(ws, &args.EnterpriseMeta)
}
if err != nil {
return err
}
reply.Index, reply.Intentions = index, ixns
if reply.Intentions == nil {
reply.Intentions = make(structs.Intentions, 0)
}
if fromConfig {
reply.DataOrigin = structs.IntentionDataOriginConfigEntries
} else {
reply.DataOrigin = structs.IntentionDataOriginLegacy
}
if err := s.srv.filterACL(args.Token, reply); err != nil {
return err
}
raw, err := filter.Execute(reply.Intentions)
if err != nil {
return err
}
reply.Intentions = raw.(structs.Intentions)
return nil
},
)
}
// Match returns the set of intentions that match the given source/destination.
func (s *Intention) Match(args *structs.IntentionQueryRequest, reply *structs.IndexedIntentionMatches) error {
// Exit early if Connect hasn't been enabled.
if !s.srv.config.ConnectEnabled {
return ErrConnectNotEnabled
}
// Forward if necessary
if done, err := s.srv.ForwardRPC("Intention.Match", args, reply); done {
return err
}
// Get the ACL token for the request for the checks below.
var entMeta structs.EnterpriseMeta
authz, err := s.srv.ResolveTokenAndDefaultMeta(args.Token, &entMeta, nil)
if err != nil {
return err
}
// Finish defaulting the namespace fields.
for i := range args.Match.Entries {
if args.Match.Entries[i].Namespace == "" {
args.Match.Entries[i].Namespace = entMeta.NamespaceOrDefault()
}
if err := s.srv.validateEnterpriseIntentionNamespace(args.Match.Entries[i].Namespace, true); err != nil {
return fmt.Errorf("Invalid match entry namespace %q: %v",
args.Match.Entries[i].Namespace, err)
}
}
if authz != nil {
var authzContext acl.AuthorizerContext
// Go through each entry to ensure we have intention:read for the resource.
// TODO - should we do this instead of filtering the result set? This will only allow
// queries for which the token has intention:read permissions on the requested side
// of the service. Should it instead return all matches that it would be able to list.
// if so we should remove this and call filterACL instead. Based on how this is used
// its probably fine. If you have intention read on the source just do a source type
// matching, if you have it on the dest then perform a dest type match.
for _, entry := range args.Match.Entries {
entry.FillAuthzContext(&authzContext)
if prefix := entry.Name; prefix != "" && authz.IntentionRead(prefix, &authzContext) != acl.Allow {
accessorID := s.aclAccessorID(args.Token)
// todo(kit) Migrate intention access denial logging over to audit logging when we implement it
s.logger.Warn("Operation on intention prefix denied due to ACLs", "prefix", prefix, "accessorID", accessorID)
return acl.ErrPermissionDenied
}
}
}
return s.srv.blockingQuery(
&args.QueryOptions,
&reply.QueryMeta,
func(ws memdb.WatchSet, state *state.Store) error {
index, matches, err := state.IntentionMatch(ws, args.Match)
if err != nil {
return err
}
reply.Index = index
reply.Matches = matches
return nil
},
)
}
// Check tests a source/destination and returns whether it would be allowed
// or denied based on the current ACL configuration.
//
// NOTE: This endpoint treats any L7 intentions as DENY.
//
// Note: Whenever the logic for this method is changed, you should take
// a look at the agent authorize endpoint (agent/agent_endpoint.go) since
// the logic there is similar.
func (s *Intention) Check(args *structs.IntentionQueryRequest, reply *structs.IntentionQueryCheckResponse) error {
// Exit early if Connect hasn't been enabled.
if !s.srv.config.ConnectEnabled {
return ErrConnectNotEnabled
}
// Forward maybe
if done, err := s.srv.ForwardRPC("Intention.Check", args, reply); done {
return err
}
// Get the test args, and defensively guard against nil
query := args.Check
if query == nil {
return errors.New("Check must be specified on args")
}
// Get the ACL token for the request for the checks below.
var entMeta structs.EnterpriseMeta
authz, err := s.srv.ResolveTokenAndDefaultMeta(args.Token, &entMeta, nil)
if err != nil {
return err
}
// Finish defaulting the namespace fields.
if query.SourceNS == "" {
query.SourceNS = entMeta.NamespaceOrDefault()
}
if query.DestinationNS == "" {
query.DestinationNS = entMeta.NamespaceOrDefault()
}
if err := s.srv.validateEnterpriseIntentionNamespace(query.SourceNS, false); err != nil {
return fmt.Errorf("Invalid source namespace %q: %v", query.SourceNS, err)
}
if err := s.srv.validateEnterpriseIntentionNamespace(query.DestinationNS, false); err != nil {
return fmt.Errorf("Invalid destination namespace %q: %v", query.DestinationNS, err)
}
if query.SourceType != structs.IntentionSourceConsul {
return fmt.Errorf("unsupported SourceType: %q", query.SourceType)
}
// Perform the ACL check. For Check we only require ServiceRead and
// NOT IntentionRead because the Check API only returns pass/fail and
// returns no other information about the intentions used. We could check
// both the source and dest side but only checking dest also has the nice
// benefit of only returning a passing status if the token would be able
// to discover the dest service and connect to it.
if prefix, ok := query.GetACLPrefix(); ok {
var authzContext acl.AuthorizerContext
query.FillAuthzContext(&authzContext)
if authz != nil && authz.ServiceRead(prefix, &authzContext) != acl.Allow {
accessorID := s.aclAccessorID(args.Token)
// todo(kit) Migrate intention access denial logging over to audit logging when we implement it
s.logger.Warn("test on intention denied due to ACLs", "prefix", prefix, "accessorID", accessorID)
return acl.ErrPermissionDenied
}
}
// Note: the default intention policy is like an intention with a
// wildcarded destination in that it is limited to L4-only.
// No match, we need to determine the default behavior. We do this by
// fetching the default intention behavior from the resolved authorizer.
// The default behavior if ACLs are disabled is to allow connections
// to mimic the behavior of Consul itself: everything is allowed if
// ACLs are disabled.
//
// NOTE(mitchellh): This is the same behavior as the agent authorize
// endpoint. If this behavior is incorrect, we should also change it there
// which is much more important.
defaultDecision := acl.Allow
if authz != nil {
defaultDecision = authz.IntentionDefaultAllow(nil)
}
state := s.srv.fsm.State()
entry := structs.IntentionMatchEntry{
Namespace: query.SourceNS,
Name: query.SourceName,
}
_, intentions, err := state.IntentionMatchOne(nil, entry, structs.IntentionMatchSource)
if err != nil {
return fmt.Errorf("failed to query intentions for %s/%s", query.SourceNS, query.SourceName)
}
decision, err := state.IntentionDecision(query.DestinationName, query.DestinationNS, intentions, structs.IntentionMatchDestination, defaultDecision, false)
if err != nil {
return fmt.Errorf("failed to get intention decision from (%s/%s) to (%s/%s): %v",
query.SourceNS, query.SourceName, query.DestinationNS, query.DestinationName, err)
}
reply.Allowed = decision.Allowed
return nil
}
// 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 (s *Intention) aclAccessorID(secretID string) string {
_, ident, err := s.srv.ResolveIdentityFromToken(secretID)
if acl.IsErrNotFound(err) {
return ""
}
if err != nil {
s.logger.Debug("non-critical error resolving acl token accessor for logging", "error", err)
return ""
}
if ident == nil {
return ""
}
return ident.ID()
}
func (s *Intention) validateEnterpriseIntention(ixn *structs.Intention) error {
if err := s.srv.validateEnterpriseIntentionNamespace(ixn.SourceNS, true); err != nil {
return fmt.Errorf("Invalid source namespace %q: %v", ixn.SourceNS, err)
}
if err := s.srv.validateEnterpriseIntentionNamespace(ixn.DestinationNS, true); err != nil {
return fmt.Errorf("Invalid destination namespace %q: %v", ixn.DestinationNS, err)
}
return nil
}
func equalStringMaps(a, b map[string]string) bool {
if len(a) != len(b) {
return false
}
for k := range a {
v, ok := b[k]
if !ok || a[k] != v {
return false
}
}
return true
}