open-consul/agent/consul/server_connect.go

298 lines
9.9 KiB
Go

package consul
import (
"context"
"crypto/x509"
"fmt"
"net/url"
"sync"
memdb "github.com/hashicorp/go-memdb"
"golang.org/x/time/rate"
"github.com/hashicorp/consul/agent/connect"
"github.com/hashicorp/consul/agent/connect/ca"
"github.com/hashicorp/consul/agent/consul/state"
"github.com/hashicorp/consul/agent/structs"
"github.com/hashicorp/consul/lib/semaphore"
)
type connectSignRateLimiter struct {
// csrRateLimiter limits the rate of signing new certs if configured. Lazily
// initialized from current config to support dynamic changes.
// csrRateLimiterMu must be held while dereferencing the pointer or storing a
// new one, but methods can be called on the limiter object outside of the
// locked section. This is done only in the getCSRRateLimiterWithLimit method.
csrRateLimiter *rate.Limiter
csrRateLimiterMu sync.RWMutex
// csrConcurrencyLimiter is a dynamically resizable semaphore used to limit
// Sign RPC concurrency if configured. The zero value is usable as soon as
// SetSize is called which we do dynamically in the RPC handler to avoid
// having to hook elaborate synchronization mechanisms through the CA config
// endpoint and config reload etc.
csrConcurrencyLimiter semaphore.Dynamic
}
// getCSRRateLimiterWithLimit returns a rate.Limiter with the desired limit set.
// It uses the shared server-wide limiter unless the limit has been changed in
// config or the limiter has not been setup yet in which case it just-in-time
// configures the new limiter. We assume that limit changes are relatively rare
// and that all callers (there is currently only one) use the same config value
// as the limit. There might be some flapping if there are multiple concurrent
// requests in flight at the time the config changes where A sees the new value
// and updates, B sees the old but then gets this lock second and changes back.
// Eventually though and very soon (once all current RPCs are complete) we are
// guaranteed to have the correct limit set by the next RPC that comes in so I
// assume this is fine. If we observe strange behavior because of it, we could
// add hysteresis that prevents changes too soon after a previous change but
// that seems unnecessary for now.
func (l *connectSignRateLimiter) getCSRRateLimiterWithLimit(limit rate.Limit) *rate.Limiter {
l.csrRateLimiterMu.RLock()
lim := l.csrRateLimiter
l.csrRateLimiterMu.RUnlock()
// If there is a current limiter with the same limit, return it. This should
// be the common case.
if lim != nil && lim.Limit() == limit {
return lim
}
// Need to change limiter, get write lock
l.csrRateLimiterMu.Lock()
defer l.csrRateLimiterMu.Unlock()
// No limiter yet, or limit changed in CA config, reconfigure a new limiter.
// We use burst of 1 for a hard limit. Note that either bursting or waiting is
// necessary to get expected behavior in fact of random arrival times, but we
// don't need both and we use Wait with a small delay to smooth noise. See
// https://github.com/banks/sim-rate-limit-backoff/blob/master/README.md.
l.csrRateLimiter = rate.NewLimiter(limit, 1)
return l.csrRateLimiter
}
// GetCARoots will retrieve
func (s *Server) GetCARoots() (*structs.IndexedCARoots, error) {
return s.getCARoots(nil, s.fsm.State())
}
func (s *Server) getCARoots(ws memdb.WatchSet, state *state.Store) (*structs.IndexedCARoots, error) {
index, roots, config, err := state.CARootsAndConfig(ws)
if err != nil {
return nil, err
}
indexedRoots := &structs.IndexedCARoots{}
if config != nil {
// Build TrustDomain based on the ClusterID stored.
signingID := connect.SpiffeIDSigningForCluster(config)
if signingID == nil {
// If CA is bootstrapped at all then this should never happen but be
// defensive.
return nil, fmt.Errorf("no cluster trust domain setup")
}
indexedRoots.TrustDomain = signingID.Host()
}
indexedRoots.Index, indexedRoots.Roots = index, roots
if indexedRoots.Roots == nil {
indexedRoots.Roots = make(structs.CARoots, 0)
}
// The response should not contain all fields as there are sensitive
// data such as key material stored within the struct. So here we
// pull out some of the fields and copy them into
for i, r := range indexedRoots.Roots {
var intermediates []string
if r.IntermediateCerts != nil {
intermediates = make([]string, len(r.IntermediateCerts))
for i, intermediate := range r.IntermediateCerts {
intermediates[i] = intermediate
}
}
// IMPORTANT: r must NEVER be modified, since it is a pointer
// directly to the structure in the memdb store.
indexedRoots.Roots[i] = &structs.CARoot{
ID: r.ID,
Name: r.Name,
SerialNumber: r.SerialNumber,
SigningKeyID: r.SigningKeyID,
ExternalTrustDomain: r.ExternalTrustDomain,
NotBefore: r.NotBefore,
NotAfter: r.NotAfter,
RootCert: ca.EnsureTrailingNewline(r.RootCert),
IntermediateCerts: intermediates,
RaftIndex: r.RaftIndex,
Active: r.Active,
PrivateKeyType: r.PrivateKeyType,
PrivateKeyBits: r.PrivateKeyBits,
}
if r.Active {
indexedRoots.ActiveRootID = r.ID
}
}
return indexedRoots, nil
}
func (s *Server) SignCertificate(csr *x509.CertificateRequest, spiffeID connect.CertURI) (*structs.IssuedCert, error) {
provider, caRoot := s.caManager.getCAProvider()
if provider == nil {
return nil, fmt.Errorf("CA is uninitialized and unable to sign certificates yet: provider is nil")
} else if caRoot == nil {
return nil, fmt.Errorf("CA is uninitialized and unable to sign certificates yet: no root certificate")
}
// Verify that the CSR entity is in the cluster's trust domain
state := s.fsm.State()
_, config, err := state.CAConfig(nil)
if err != nil {
return nil, err
}
signingID := connect.SpiffeIDSigningForCluster(config)
serviceID, isService := spiffeID.(*connect.SpiffeIDService)
agentID, isAgent := spiffeID.(*connect.SpiffeIDAgent)
if !isService && !isAgent {
return nil, fmt.Errorf("SPIFFE ID in CSR must be a service or agent ID")
}
var entMeta structs.EnterpriseMeta
if isService {
if !signingID.CanSign(spiffeID) {
return nil, fmt.Errorf("SPIFFE ID in CSR from a different trust domain: %s, "+
"we are %s", serviceID.Host, signingID.Host())
}
entMeta.Merge(serviceID.GetEnterpriseMeta())
} else {
// isAgent - if we support more ID types then this would need to be an else if
// here we are just automatically fixing the trust domain. For auto-encrypt and
// auto-config they make certificate requests before learning about the roots
// so they will have a dummy trust domain in the CSR.
trustDomain := signingID.Host()
if agentID.Host != trustDomain {
originalURI := agentID.URI()
agentID.Host = trustDomain
// recreate the URIs list
uris := make([]*url.URL, len(csr.URIs))
for i, uri := range csr.URIs {
if originalURI.String() == uri.String() {
uris[i] = agentID.URI()
} else {
uris[i] = uri
}
}
csr.URIs = uris
}
entMeta.Merge(structs.DefaultEnterpriseMeta())
}
commonCfg, err := config.GetCommonConfig()
if err != nil {
return nil, err
}
if commonCfg.CSRMaxPerSecond > 0 {
lim := s.caLeafLimiter.getCSRRateLimiterWithLimit(rate.Limit(commonCfg.CSRMaxPerSecond))
// Wait up to the small threshold we allow for a token.
ctx, cancel := context.WithTimeout(context.Background(), csrLimitWait)
defer cancel()
if lim.Wait(ctx) != nil {
return nil, ErrRateLimited
}
} else if commonCfg.CSRMaxConcurrent > 0 {
s.caLeafLimiter.csrConcurrencyLimiter.SetSize(int64(commonCfg.CSRMaxConcurrent))
ctx, cancel := context.WithTimeout(context.Background(), csrLimitWait)
defer cancel()
if err := s.caLeafLimiter.csrConcurrencyLimiter.Acquire(ctx); err != nil {
return nil, ErrRateLimited
}
defer s.caLeafLimiter.csrConcurrencyLimiter.Release()
}
connect.HackSANExtensionForCSR(csr)
// All seems to be in order, actually sign it.
pem, err := provider.Sign(csr)
if err == ca.ErrRateLimited {
return nil, ErrRateLimited
}
if err != nil {
return nil, err
}
// Append any intermediates needed by this root.
for _, p := range caRoot.IntermediateCerts {
pem = pem + ca.EnsureTrailingNewline(p)
}
// Append our local CA's intermediate if there is one.
inter, err := provider.ActiveIntermediate()
if err != nil {
return nil, err
}
root, err := provider.ActiveRoot()
if err != nil {
return nil, err
}
if inter != root {
pem = pem + ca.EnsureTrailingNewline(inter)
}
// TODO(banks): when we implement IssuedCerts table we can use the insert to
// that as the raft index to return in response.
//
// UPDATE(mkeeler): The original implementation relied on updating the CAConfig
// and using its index as the ModifyIndex for certs. This was buggy. The long
// term goal is still to insert some metadata into raft about the certificates
// and use that raft index for the ModifyIndex. This is a partial step in that
// direction except that we only are setting an index and not storing the
// metadata.
req := structs.CALeafRequest{
Op: structs.CALeafOpIncrementIndex,
Datacenter: s.config.Datacenter,
}
resp, err := s.raftApply(structs.ConnectCALeafRequestType|structs.IgnoreUnknownTypeFlag, &req)
if err != nil {
return nil, err
}
modIdx, ok := resp.(uint64)
if !ok {
return nil, fmt.Errorf("Invalid response from updating the leaf cert index")
}
cert, err := connect.ParseCert(pem)
if err != nil {
return nil, err
}
// Set the response
reply := structs.IssuedCert{
SerialNumber: connect.EncodeSerialNumber(cert.SerialNumber),
CertPEM: pem,
ValidAfter: cert.NotBefore,
ValidBefore: cert.NotAfter,
EnterpriseMeta: entMeta,
RaftIndex: structs.RaftIndex{
ModifyIndex: modIdx,
CreateIndex: modIdx,
},
}
if isService {
reply.Service = serviceID.Service
reply.ServiceURI = cert.URIs[0].String()
} else if isAgent {
reply.Agent = agentID.Agent
reply.AgentURI = cert.URIs[0].String()
}
return &reply, nil
}