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proxy doesn't need the host key, it's just a TCP proxy

Signed-off-by: Jason Hall <jason@chainguard.dev>
This commit is contained in:
Jason Hall 2025-09-13 22:44:05 -04:00
parent e2a005577f
commit 4c08c8a3c8
5 changed files with 7 additions and 83 deletions

View file

@ -45,7 +45,3 @@ http.ListenAndServe(":8080", nil)
## Authentication
The SSH proxy supports Google Cloud identity token authentication for secure WebSocket connections. When connecting to Cloud Run services, the proxy automatically obtains and includes identity tokens in the Authorization header.
## SSH Host Key
The SSH server's host key is loaded from Google Cloud Secret Manager at startup.

View file

@ -15,14 +15,16 @@ import (
var env = envconfig.MustProcess(context.Background(), &struct {
WebsocketURL string `env:"WEBSOCKET_URL,required"`
SSHAddr string `env:"SSH_ADDR,default=:22"`
Port int `env:"PORT,default=8080"`
SSHKeySecret string `env:"SSH_KEY_SECRET,required"` // full resource name.
}{})
func main() {
ctx, cancel := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
defer cancel()
if err := sshproxy.NewProxy(env.WebsocketURL, env.SSHAddr, env.SSHKeySecret).Start(ctx); err != nil {
if err := (&sshproxy.Proxy{
WebsocketURL: env.WebsocketURL,
SSHAddr: env.SSHAddr,
}).Start(ctx); err != nil {
clog.FatalContext(ctx, "failed to start SSH proxy", "error", err)
}
}

10
go.mod
View file

@ -12,14 +12,9 @@ require (
)
require (
cloud.google.com/go v0.120.0 // indirect
cloud.google.com/go/auth v0.16.4 // indirect
cloud.google.com/go/auth/oauth2adapt v0.2.8 // indirect
cloud.google.com/go/compute/metadata v0.8.0 // indirect
cloud.google.com/go/iam v1.5.2 // indirect
cloud.google.com/go/kms v1.23.0 // indirect
cloud.google.com/go/longrunning v0.6.7 // indirect
cloud.google.com/go/secretmanager v1.15.0 // indirect
github.com/felixge/httpsnoop v1.0.4 // indirect
github.com/go-logr/logr v1.4.3 // indirect
github.com/go-logr/stdr v1.2.2 // indirect
@ -27,19 +22,14 @@ require (
github.com/googleapis/enterprise-certificate-proxy v0.3.6 // indirect
github.com/googleapis/gax-go/v2 v2.15.0 // indirect
go.opentelemetry.io/auto/sdk v1.1.0 // indirect
go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.61.0 // indirect
go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.61.0 // indirect
go.opentelemetry.io/otel v1.36.0 // indirect
go.opentelemetry.io/otel/metric v1.36.0 // indirect
go.opentelemetry.io/otel/trace v1.36.0 // indirect
golang.org/x/crypto v0.41.0 // indirect
golang.org/x/net v0.43.0 // indirect
golang.org/x/sync v0.16.0 // indirect
golang.org/x/sys v0.35.0 // indirect
golang.org/x/text v0.28.0 // indirect
golang.org/x/time v0.12.0 // indirect
google.golang.org/genproto v0.0.0-20250603155806-513f23925822 // indirect
google.golang.org/genproto/googleapis/api v0.0.0-20250818200422-3122310a409c // indirect
google.golang.org/genproto/googleapis/rpc v0.0.0-20250811230008-5f3141c8851a // indirect
google.golang.org/grpc v1.74.2 // indirect
google.golang.org/protobuf v1.36.7 // indirect

26
go.sum
View file

@ -1,23 +1,9 @@
cloud.google.com/go v0.120.0 h1:wc6bgG9DHyKqF5/vQvX1CiZrtHnxJjBlKUyF9nP6meA=
cloud.google.com/go v0.120.0/go.mod h1:/beW32s8/pGRuj4IILWQNd4uuebeT4dkOhKmkfit64Q=
cloud.google.com/go/auth v0.16.3 h1:kabzoQ9/bobUmnseYnBO6qQG7q4a/CffFRlJSxv2wCc=
cloud.google.com/go/auth v0.16.3/go.mod h1:NucRGjaXfzP1ltpcQ7On/VTZ0H4kWB5Jy+Y9Dnm76fA=
cloud.google.com/go/auth v0.16.4 h1:fXOAIQmkApVvcIn7Pc2+5J8QTMVbUGLscnSVNl11su8=
cloud.google.com/go/auth v0.16.4/go.mod h1:j10ncYwjX/g3cdX7GpEzsdM+d+ZNsXAbb6qXA7p1Y5M=
cloud.google.com/go/auth/oauth2adapt v0.2.8 h1:keo8NaayQZ6wimpNSmW5OPc283g65QNIiLpZnkHRbnc=
cloud.google.com/go/auth/oauth2adapt v0.2.8/go.mod h1:XQ9y31RkqZCcwJWNSx2Xvric3RrU88hAYYbjDWYDL+c=
cloud.google.com/go/compute/metadata v0.7.0 h1:PBWF+iiAerVNe8UCHxdOt6eHLVc3ydFeOCw78U8ytSU=
cloud.google.com/go/compute/metadata v0.7.0/go.mod h1:j5MvL9PprKL39t166CoB1uVHfQMs4tFQZZcKwksXUjo=
cloud.google.com/go/compute/metadata v0.8.0 h1:HxMRIbao8w17ZX6wBnjhcDkW6lTFpgcaobyVfZWqRLA=
cloud.google.com/go/compute/metadata v0.8.0/go.mod h1:sYOGTp851OV9bOFJ9CH7elVvyzopvWQFNNghtDQ/Biw=
cloud.google.com/go/iam v1.5.2 h1:qgFRAGEmd8z6dJ/qyEchAuL9jpswyODjA2lS+w234g8=
cloud.google.com/go/iam v1.5.2/go.mod h1:SE1vg0N81zQqLzQEwxL2WI6yhetBdbNQuTvIKCSkUHE=
cloud.google.com/go/kms v1.23.0 h1:WaqAZsUptyHwOo9II8rFC1Kd2I+yvNsNP2IJ14H2sUw=
cloud.google.com/go/kms v1.23.0/go.mod h1:rZ5kK0I7Kn9W4erhYVoIRPtpizjunlrfU4fUkumUp8g=
cloud.google.com/go/longrunning v0.6.7 h1:IGtfDWHhQCgCjwQjV9iiLnUta9LBCo8R9QmAFsS/PrE=
cloud.google.com/go/longrunning v0.6.7/go.mod h1:EAFV3IZAKmM56TyiE6VAP3VoTzhZzySwI/YI1s/nRsY=
cloud.google.com/go/secretmanager v1.15.0 h1:RtkCMgTpaBMbzozcRUGfZe46jb9a3qh5EdEtVRUATF8=
cloud.google.com/go/secretmanager v1.15.0/go.mod h1:1hQSAhKK7FldiYw//wbR/XPfPc08eQ81oBsnRUHEvUc=
github.com/chainguard-dev/clog v1.7.0 h1:guPznsK8vLHvzz1QJe2yU6MFeYaiSOFOQBYw4OXu+g8=
github.com/chainguard-dev/clog v1.7.0/go.mod h1:4+WFhRMsGH79etYXY3plYdp+tCz/KCkU8fAr0HoaPvs=
github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
@ -67,8 +53,6 @@ go.opentelemetry.io/otel/trace v1.36.0 h1:ahxWNuqZjpdiFAyrIoQ4GIiAIhxAunQR6MUoKr
go.opentelemetry.io/otel/trace v1.36.0/go.mod h1:gQ+OnDZzrybY4k4seLzPAWNwVBBVlF2szhehOBB/tGA=
golang.org/x/crypto v0.41.0 h1:WKYxWedPGCTVVl5+WHSSrOBT0O8lx32+zxmHxijgXp4=
golang.org/x/crypto v0.41.0/go.mod h1:pO5AFd7FA68rFak7rOAGVuygIISepHftHnr8dr6+sUc=
golang.org/x/net v0.42.0 h1:jzkYrhi3YQWD6MLBJcsklgQsoAcw89EcZbJw8Z614hs=
golang.org/x/net v0.42.0/go.mod h1:FF1RA5d3u7nAYA4z2TkclSCKh68eSXtiFwcWQpPXdt8=
golang.org/x/net v0.43.0 h1:lat02VYK2j4aLzMzecihNvTlJNQUq316m2Mr9rnM6YE=
golang.org/x/net v0.43.0/go.mod h1:vhO1fvI4dGsIjh73sWfUVjj3N7CA9WkKJNQm2svM6Jg=
golang.org/x/oauth2 v0.30.0 h1:dnDm7JmhM45NNpd8FDDeLhK6FwqbOf4MLCM9zb1BOHI=
@ -81,22 +65,12 @@ golang.org/x/text v0.28.0 h1:rhazDwis8INMIwQ4tpjLDzUhx6RlXqZNPEM0huQojng=
golang.org/x/text v0.28.0/go.mod h1:U8nCwOR8jO/marOQ0QbDiOngZVEBB7MAiitBuMjXiNU=
golang.org/x/time v0.12.0 h1:ScB/8o8olJvc+CQPWrK3fPZNfh7qgwCrY0zJmoEQLSE=
golang.org/x/time v0.12.0/go.mod h1:CDIdPxbZBQxdj6cxyCIdrNogrJKMJ7pr37NYpMcMDSg=
google.golang.org/api v0.246.0 h1:H0ODDs5PnMZVZAEtdLMn2Ul2eQi7QNjqM2DIFp8TlTM=
google.golang.org/api v0.246.0/go.mod h1:dMVhVcylamkirHdzEBAIQWUCgqY885ivNeZYd7VAVr8=
google.golang.org/api v0.247.0 h1:tSd/e0QrUlLsrwMKmkbQhYVa109qIintOls2Wh6bngc=
google.golang.org/api v0.247.0/go.mod h1:r1qZOPmxXffXg6xS5uhx16Fa/UFY8QU/K4bfKrnvovM=
google.golang.org/genproto v0.0.0-20250603155806-513f23925822 h1:rHWScKit0gvAPuOnu87KpaYtjK5zBMLcULh7gxkCXu4=
google.golang.org/genproto v0.0.0-20250603155806-513f23925822/go.mod h1:HubltRL7rMh0LfnQPkMH4NPDFEWp0jw3vixw7jEM53s=
google.golang.org/genproto/googleapis/api v0.0.0-20250818200422-3122310a409c h1:AtEkQdl5b6zsybXcbz00j1LwNodDuH6hVifIaNqk7NQ=
google.golang.org/genproto/googleapis/api v0.0.0-20250818200422-3122310a409c/go.mod h1:ea2MjsO70ssTfCjiwHgI0ZFqcw45Ksuk2ckf9G468GA=
google.golang.org/genproto/googleapis/rpc v0.0.0-20250728155136-f173205681a0 h1:MAKi5q709QWfnkkpNQ0M12hYJ1+e8qYVDyowc4U1XZM=
google.golang.org/genproto/googleapis/rpc v0.0.0-20250728155136-f173205681a0/go.mod h1:qQ0YXyHHx3XkvlzUtpXDkS29lDSafHMZBAZDc03LQ3A=
google.golang.org/genproto/googleapis/rpc v0.0.0-20250811230008-5f3141c8851a h1:tPE/Kp+x9dMSwUm/uM0JKK0IfdiJkwAbSMSeZBXXJXc=
google.golang.org/genproto/googleapis/rpc v0.0.0-20250811230008-5f3141c8851a/go.mod h1:gw1tLEfykwDz2ET4a12jcXt4couGAm7IwsVaTy0Sflo=
google.golang.org/grpc v1.74.2 h1:WoosgB65DlWVC9FqI82dGsZhWFNBSLjQ84bjROOpMu4=
google.golang.org/grpc v1.74.2/go.mod h1:CtQ+BGjaAIXHs/5YS3i473GqwBBa1zGQNevxdeBEXrM=
google.golang.org/protobuf v1.36.6 h1:z1NpPI8ku2WgiWnf+t9wTPsn6eP1L7ksHUlkfLvd9xY=
google.golang.org/protobuf v1.36.6/go.mod h1:jduwjTPXsFjZGTmRluh+L6NjiWu7pchiJ2/5YcXBHnY=
google.golang.org/protobuf v1.36.7 h1:IgrO7UwFQGJdRNXH/sQux4R1Dj1WAKcLElzeeRaXV2A=
google.golang.org/protobuf v1.36.7/go.mod h1:jduwjTPXsFjZGTmRluh+L6NjiWu7pchiJ2/5YcXBHnY=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=

View file

@ -9,8 +9,6 @@ import (
"net/http"
"net/url"
secretmanager "cloud.google.com/go/secretmanager/apiv1"
"cloud.google.com/go/secretmanager/apiv1/secretmanagerpb"
"github.com/chainguard-dev/clog"
"github.com/gorilla/websocket"
"golang.org/x/oauth2"
@ -21,28 +19,17 @@ import (
type Proxy struct {
WebsocketURL string
SSHAddr string
SSHKeySecret string
sshPrivateKey []byte
}
// NewProxy creates a new SSH proxy
func NewProxy(websocketURL, sshAddr, sshKeySecret string) *Proxy {
return &Proxy{WebsocketURL: websocketURL, SSHAddr: sshAddr, SSHKeySecret: sshKeySecret}
func NewProxy(websocketURL, sshAddr string) *Proxy {
return &Proxy{WebsocketURL: websocketURL, SSHAddr: sshAddr}
}
// Start starts the SSH proxy server
func (p *Proxy) Start(ctx context.Context) error {
log := clog.FromContext(ctx)
// Retrieve SSH private key from Secret Manager.
key, err := p.getSSHPrivateKey(ctx)
if err != nil {
return fmt.Errorf("failed to retrieve SSH private key: %w", err)
}
p.sshPrivateKey = key
log.Info("SSH private key loaded from Secret Manager", "secret", p.SSHKeySecret)
listener, err := net.Listen("tcp", p.SSHAddr)
if err != nil {
return fmt.Errorf("failed to listen on %s: %w", p.SSHAddr, err)
@ -154,28 +141,3 @@ func ProxySSHToWebSocket(ctx context.Context, sshConn net.Conn, wsURL *url.URL,
return err
}
}
// getSSHPrivateKey retrieves the SSH private key from Secret Manager
func (p *Proxy) getSSHPrivateKey(ctx context.Context) ([]byte, error) {
log := clog.FromContext(ctx)
client, err := secretmanager.NewClient(ctx)
if err != nil {
return nil, fmt.Errorf("failed to create Secret Manager client: %w", err)
}
defer client.Close()
// Access the secret version
result, err := client.AccessSecretVersion(ctx, &secretmanagerpb.AccessSecretVersionRequest{Name: p.SSHKeySecret})
if err != nil {
return nil, fmt.Errorf("failed to access secret %s: %w", p.SSHKeySecret, err)
}
log.Info("Successfully retrieved SSH private key from Secret Manager", "secret", p.SSHKeySecret)
return result.Payload.Data, nil
}
// GetSSHPrivateKey returns the loaded SSH private key
func (p *Proxy) GetSSHPrivateKey() []byte {
return p.sshPrivateKey
}