diff options
| -rw-r--r-- | cmd/k8s-operator/depaware.txt | 1 | ||||
| -rw-r--r-- | cmd/tailscaled/depaware.txt | 1 | ||||
| -rw-r--r-- | control/controlclient/direct.go | 40 | ||||
| -rw-r--r-- | control/keyfallback/control-key.json | 4 | ||||
| -rw-r--r-- | control/keyfallback/keyfallback.go | 32 | ||||
| -rw-r--r-- | control/keyfallback/keyfallback_test.go | 77 | ||||
| -rw-r--r-- | control/keyfallback/update.go | 47 |
7 files changed, 196 insertions, 6 deletions
diff --git a/cmd/k8s-operator/depaware.txt b/cmd/k8s-operator/depaware.txt index 19d6808d7..6123d562d 100644 --- a/cmd/k8s-operator/depaware.txt +++ b/cmd/k8s-operator/depaware.txt @@ -659,6 +659,7 @@ tailscale.com/cmd/k8s-operator dependencies: (generated by github.com/tailscale/ tailscale.com/control/controlclient from tailscale.com/ipn/ipnlocal+ tailscale.com/control/controlhttp from tailscale.com/control/controlclient tailscale.com/control/controlknobs from tailscale.com/control/controlclient+ + tailscale.com/control/keyfallback from tailscale.com/control/controlclient tailscale.com/derp from tailscale.com/derp/derphttp+ tailscale.com/derp/derphttp from tailscale.com/ipn/localapi+ tailscale.com/disco from tailscale.com/derp+ diff --git a/cmd/tailscaled/depaware.txt b/cmd/tailscaled/depaware.txt index 26165d659..7d24129da 100644 --- a/cmd/tailscaled/depaware.txt +++ b/cmd/tailscaled/depaware.txt @@ -250,6 +250,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de tailscale.com/control/controlclient from tailscale.com/cmd/tailscaled+ tailscale.com/control/controlhttp from tailscale.com/control/controlclient tailscale.com/control/controlknobs from tailscale.com/control/controlclient+ + tailscale.com/control/keyfallback from tailscale.com/control/controlclient tailscale.com/derp from tailscale.com/derp/derphttp+ tailscale.com/derp/derphttp from tailscale.com/cmd/tailscaled+ tailscale.com/disco from tailscale.com/derp+ diff --git a/control/controlclient/direct.go b/control/controlclient/direct.go index 9cbd0e14e..599e7fba5 100644 --- a/control/controlclient/direct.go +++ b/control/controlclient/direct.go @@ -29,9 +29,11 @@ import ( "go4.org/mem" "tailscale.com/control/controlknobs" + "tailscale.com/control/keyfallback" "tailscale.com/envknob" "tailscale.com/health" "tailscale.com/hostinfo" + "tailscale.com/ipn" "tailscale.com/ipn/ipnstate" "tailscale.com/logtail" "tailscale.com/net/dnscache" @@ -87,9 +89,10 @@ type Direct struct { dialPlan ControlDialPlanner // can be nil - mu sync.Mutex // mutex guards the following fields - serverLegacyKey key.MachinePublic // original ("legacy") nacl crypto_box-based public key; only used for signRegisterRequest on Windows now - serverNoiseKey key.MachinePublic + mu sync.Mutex // mutex guards the following fields + serverLegacyKey key.MachinePublic // original ("legacy") nacl crypto_box-based public key; only used for signRegisterRequest on Windows now + serverNoiseKey key.MachinePublic + usedFallbackNoiseKey bool // true if we used the baked-in fallback key sfGroup singleflight.Group[struct{}, *NoiseClient] // protects noiseClient creation. noiseClient *NoiseClient @@ -498,6 +501,7 @@ func (c *Direct) doLogin(ctx context.Context, opt loginOpt) (mustRegen bool, new tryingNewKey := c.tryingNewKey serverKey := c.serverLegacyKey serverNoiseKey := c.serverNoiseKey + usedFallback := c.usedFallbackNoiseKey authKey, isWrapped, wrappedSig, wrappedKey := tka.DecodeWrappedAuthkey(c.authKey, c.logf) hi := c.hostInfoLocked() backendLogID := hi.BackendLogID @@ -528,7 +532,7 @@ func (c *Direct) doLogin(ctx context.Context, opt loginOpt) (mustRegen bool, new } c.logf("doLogin(regen=%v, hasUrl=%v)", regen, opt.URL != "") - if serverKey.IsZero() { + if serverKey.IsZero() || usedFallback { keys, err := loadServerPubKeys(ctx, c.httpc, c.serverURL) if err != nil && c.interceptedDial != nil && c.interceptedDial.Load() { c.health.SetUnhealthy(macOSScreenTime, nil) @@ -536,13 +540,21 @@ func (c *Direct) doLogin(ctx context.Context, opt loginOpt) (mustRegen bool, new c.health.SetHealthy(macOSScreenTime) } if err != nil { - return regen, opt.URL, nil, err + if k2, err := c.getFallbackServerPubKeys(); err == nil { + keys = k2 + usedFallback = true + } else { + return regen, opt.URL, nil, err + } + } else { + usedFallback = false + c.logf("control server key from %s: ts2021=%s", c.serverURL, keys.PublicKey.ShortString()) } - c.logf("control server key from %s: ts2021=%s, legacy=%v", c.serverURL, keys.PublicKey.ShortString(), keys.LegacyPublicKey.ShortString()) c.mu.Lock() c.serverLegacyKey = keys.LegacyPublicKey c.serverNoiseKey = keys.PublicKey + c.usedFallbackNoiseKey = usedFallback c.mu.Unlock() serverKey = keys.LegacyPublicKey serverNoiseKey = keys.PublicKey @@ -751,6 +763,22 @@ func (c *Direct) doLogin(ctx context.Context, opt loginOpt) (mustRegen bool, new return false, resp.AuthURL, nil, nil } +func (c *Direct) getFallbackServerPubKeys() (*tailcfg.OverTLSPublicKeyResponse, error) { + // If we saw an error, try to use the fallback key if + // we're dialing the default control server. + if ipn.IsLoginServerSynonym(c.serverURL) { + return nil, errors.New("not using default control server") + } + + kf, err := keyfallback.Get() + if err != nil { + return nil, err + } + + c.logf("using fallback server key: ts2021=%s", kf.PublicKey.ShortString()) + return kf, nil +} + // newEndpoints acquires c.mu and sets the local port and endpoints and reports // whether they've changed. // diff --git a/control/keyfallback/control-key.json b/control/keyfallback/control-key.json new file mode 100644 index 000000000..a7ebf8e94 --- /dev/null +++ b/control/keyfallback/control-key.json @@ -0,0 +1,4 @@ +{ + "legacyPublicKey": "mkey:9e5156a4c65121306dd2d8ed8f92cb8d738e2533011344b522c5d28409bc4970", + "publicKey": "mkey:7d2792f9c98d753d2042471536801949104c247f95eac770f8fb321595e2173b" +}
\ No newline at end of file diff --git a/control/keyfallback/keyfallback.go b/control/keyfallback/keyfallback.go new file mode 100644 index 000000000..44a190f69 --- /dev/null +++ b/control/keyfallback/keyfallback.go @@ -0,0 +1,32 @@ +// Copyright (c) Tailscale Inc & AUTHORS +// SPDX-License-Identifier: BSD-3-Clause + +// Package keyfallback contains a fallback mechanism for starting up Tailscale +// when the control server cannot be reached to obtain the primary Noise key. +// +// The data is backed by a JSON file `control-key.json` that is updated by +// `update.go`: +// +// (cd control/keyfallback; go run update.go) +package keyfallback + +import ( + _ "embed" + "encoding/json" + + "tailscale.com/tailcfg" +) + +// Get returns the fallback control server public key that was baked into the +// binary at compile time. It is only valid for the main Tailscale control +// server instance. +func Get() (*tailcfg.OverTLSPublicKeyResponse, error) { + out := &tailcfg.OverTLSPublicKeyResponse{} + if err := json.Unmarshal(controlKeyJSON, out); err != nil { + return nil, err + } + return out, nil +} + +//go:embed control-key.json +var controlKeyJSON []byte diff --git a/control/keyfallback/keyfallback_test.go b/control/keyfallback/keyfallback_test.go new file mode 100644 index 000000000..92aa6b0e6 --- /dev/null +++ b/control/keyfallback/keyfallback_test.go @@ -0,0 +1,77 @@ +// Copyright (c) Tailscale Inc & AUTHORS +// SPDX-License-Identifier: BSD-3-Clause + +package keyfallback + +import ( + "context" + "encoding/json" + "fmt" + "io" + "net/http" + "reflect" + "testing" + "time" + + "tailscale.com/ipn" + "tailscale.com/tailcfg" + "tailscale.com/tstest/nettest" + "tailscale.com/util/must" +) + +func TestHasValidControlKey(t *testing.T) { + t.Parallel() + keys, err := Get() + if err != nil { + t.Fatalf("Get: %v", err) + } + if keys.PublicKey.IsZero() { + t.Fatalf("zero key") + } +} + +// TestKeyIsUpToDate fetches the control key from the control server and +// compares it to the baked-in key, to verify that it's up-to-date. If the +// control server is unreachable, the test is skipped. +func TestKeyIsUpToDate(t *testing.T) { + nettest.SkipIfNoNetwork(t) + + // Optimistically fetch the control key and check if it's up to date, + // but ignore if we don't have network access (e.g. running tests on an + // airplane). + ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second) + defer cancel() + keyURL := fmt.Sprintf("%v/key?v=%d", ipn.DefaultControlURL, tailcfg.CurrentCapabilityVersion) + req := must.Get(http.NewRequestWithContext(ctx, "GET", keyURL, nil)) + res, err := http.DefaultClient.Do(req) + if err != nil { + t.Logf("fetch control key: %v", err) + return + } + defer res.Body.Close() + + if res.StatusCode != 200 { + t.Fatalf("fetch control key: bad status; got %v, want 200", res.Status) + } + b, err := io.ReadAll(res.Body) + if err != nil { + t.Fatalf("read control key: %v", err) + } + + // Verify that the key is up to date and matches the baked-in key. + out := &tailcfg.OverTLSPublicKeyResponse{} + if err := json.Unmarshal(b, out); err != nil { + t.Fatalf("unmarshal control key: %v", err) + } + + keys, err := Get() + if err != nil { + t.Fatalf("Get: %v", err) + } + + if !reflect.DeepEqual(keys, out) { + t.Errorf("control key is out of date") + t.Logf("old key: %v", keys) + t.Logf("new key: %v", out) + } +} diff --git a/control/keyfallback/update.go b/control/keyfallback/update.go new file mode 100644 index 000000000..27bee37ad --- /dev/null +++ b/control/keyfallback/update.go @@ -0,0 +1,47 @@ +// Copyright (c) Tailscale Inc & AUTHORS +// SPDX-License-Identifier: BSD-3-Clause + +//go:build ignore + +package main + +import ( + "encoding/json" + "fmt" + "io" + "log" + "net/http" + "os" + + "tailscale.com/ipn" + "tailscale.com/tailcfg" +) + +func main() { + keyURL := fmt.Sprintf("%v/key?v=%d", ipn.DefaultControlURL, tailcfg.CurrentCapabilityVersion) + res, err := http.Get(keyURL) + if err != nil { + log.Fatalf("fetch control key: %v", err) + } + defer res.Body.Close() + b, err := io.ReadAll(io.LimitReader(res.Body, 64<<10)) + if err != nil { + log.Fatalf("read control key: %v", err) + } + if res.StatusCode != 200 { + log.Fatalf("fetch control key: bad status; got %v, want 200", res.Status) + } + + // Unmarshal to make sure it's valid. + var out tailcfg.OverTLSPublicKeyResponse + if err := json.Unmarshal(b, &out); err != nil { + log.Fatalf("unmarshal control key: %v", err) + } + if out.PublicKey.IsZero() { + log.Fatalf("control key is zero") + } + + if err := os.WriteFile("control-key.json", b, 0644); err != nil { + log.Fatalf("write control key: %v", err) + } +} |