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|
package agent
import (
"context"
"crypto/tls"
"errors"
"fmt"
"io"
"net"
"net/http"
"net/url"
"strings"
"time"
"gitlab.com/gitlab-org/cluster-integration/gitlab-agent/v16/internal/module/kubernetes_api/rpc"
"gitlab.com/gitlab-org/cluster-integration/gitlab-agent/v16/internal/module/modagent"
"gitlab.com/gitlab-org/cluster-integration/gitlab-agent/v16/internal/module/modshared"
"gitlab.com/gitlab-org/cluster-integration/gitlab-agent/v16/internal/tool/grpctool"
"gitlab.com/gitlab-org/cluster-integration/gitlab-agent/v16/internal/tool/httpz"
"gitlab.com/gitlab-org/cluster-integration/gitlab-agent/v16/internal/tool/prototool"
"gitlab.com/gitlab-org/cluster-integration/gitlab-agent/v16/internal/tool/tlstool"
"k8s.io/client-go/rest"
"k8s.io/client-go/transport"
)
type server struct {
rpc.UnimplementedKubernetesApiServer
restConfig *rest.Config
baseUrl *url.URL
userAgent string
via string
}
func newServer(restConfig *rest.Config, baseUrl *url.URL, userAgent string) *server {
return &server{
restConfig: restConfig,
baseUrl: baseUrl,
userAgent: userAgent,
via: "gRPC/1.0 " + userAgent,
}
}
func (s *server) MakeRequest(server rpc.KubernetesApi_MakeRequestServer) error {
rpcApi := modagent.RpcApiFromContext(server.Context())
log := rpcApi.Log()
grpc2http := grpctool.InboundGrpcToOutboundHttp{
Log: log,
HandleProcessingError: func(msg string, err error) {
rpcApi.HandleProcessingError(log, modshared.NoAgentId, msg, err)
},
HandleIoError: func(msg string, err error) error {
return rpcApi.HandleIoError(log, msg, err)
},
HttpDo: s.httpDo,
}
return grpc2http.Pipe(server)
}
func (s *server) httpDo(ctx context.Context, h *grpctool.HttpRequest_Header, body io.Reader) (grpctool.DoResponse, error) {
// 1. Construct request
req, err := s.newRequest(ctx, h.Request, body)
if err != nil {
return grpctool.DoResponse{}, err
}
// 2. Construct rest config
var headerExtra rpc.HeaderExtra
if h.Extra != nil { // Optional field.
err = h.Extra.UnmarshalTo(&headerExtra)
if err != nil {
return grpctool.DoResponse{}, err
}
}
restConfig, err := restImpersonationConfig(headerExtra.ImpConfig, s.restConfig, req)
if err != nil {
return grpctool.DoResponse{}, err
}
// 3. Construct round tripper
var (
rt http.RoundTripper
upgradeRT *httpz.UpgradeRoundTripper
)
transportCfg, err := restConfig.TransportConfig()
if err != nil {
return grpctool.DoResponse{}, err
}
isUpgrade := h.Request.IsUpgrade()
if isUpgrade {
var tlsConfig *tls.Config
tlsConfig, err = transport.TLSConfigFor(transportCfg)
if err != nil {
return grpctool.DoResponse{}, err
}
if tlsConfig == nil { // transport.TLSConfigFor() can return nil
tlsConfig = tlstool.DefaultClientTLSConfig()
}
tlsConfig.NextProtos = []string{httpz.TLSNextProtoH1} // HTTP Upgrade doesn't work over HTTP/2, so enforce HTTP/1.1
dialer := &net.Dialer{
Timeout: 30 * time.Second,
}
upgradeRT = &httpz.UpgradeRoundTripper{
Dialer: dialer,
TlsDialer: &tls.Dialer{
NetDialer: dialer,
Config: tlsConfig,
},
}
rt, err = transport.HTTPWrappersForConfig(transportCfg, upgradeRT)
} else {
rt, err = transport.New(transportCfg) // returns pooled transports that reuse TCP connections
}
if err != nil {
return grpctool.DoResponse{}, err
}
// 4. Make a request
resp, err := rt.RoundTrip(req) // nolint: bodyclose
if err != nil {
ctxErr := ctx.Err()
if ctxErr != nil {
err = ctxErr // assume request errored out because of context
}
return grpctool.DoResponse{}, err
}
resp.Header[httpz.ViaHeader] = append(resp.Header[httpz.ViaHeader], fmt.Sprintf("%d.%d %s", resp.ProtoMajor, resp.ProtoMinor, s.userAgent))
if isUpgrade {
return grpctool.DoResponse{
Resp: resp,
UpgradeConn: upgradeRT.Conn,
ConnReader: upgradeRT.ConnReader,
}, nil
} else {
return grpctool.DoResponse{
Resp: resp,
}, nil
}
}
func (s *server) newRequest(ctx context.Context, requestInfo *prototool.HttpRequest, body io.Reader) (*http.Request, error) {
u := *s.baseUrl
u.Path = requestInfo.UrlPath
u.RawQuery = requestInfo.UrlQuery().Encode()
req, err := http.NewRequestWithContext(ctx, requestInfo.Method, u.String(), body)
if err != nil {
return nil, err
}
req.Header = requestInfo.HttpHeader()
req.Header[httpz.ViaHeader] = append(req.Header[httpz.ViaHeader], s.via)
return req, nil
}
func restImpersonationConfig(impConfig *rpc.ImpersonationConfig, restConfig *rest.Config, r *http.Request) (*rest.Config, error) {
restImp := !isEmptyImpersonationConfig(restConfig.Impersonate)
cfgImp := !impConfig.IsEmpty()
reqImp := hasImpersonationHeaders(r)
switch {
case !restImp && !cfgImp && !reqImp:
// No impersonation
case restImp && !cfgImp && !reqImp:
// Impersonation is configured in the rest config
case !restImp && cfgImp && !reqImp:
// Impersonation is configured in the agent config
restConfig = rest.CopyConfig(restConfig) // copy to avoid mutating a potentially shared config object
restConfig.Impersonate.UserName = impConfig.Username
restConfig.Impersonate.UID = impConfig.Uid
restConfig.Impersonate.Groups = impConfig.Groups
restConfig.Impersonate.Extra = impConfig.GetExtraAsMap()
case !restImp && !cfgImp && reqImp:
// Impersonation is configured in the HTTP request
default:
// Nested impersonation support https://gitlab.com/gitlab-org/gitlab/-/issues/338664
return nil, errors.New("nested impersonation is not supported - agent is already configured to impersonate an identity")
}
return restConfig, nil
}
func isEmptyImpersonationConfig(cfg rest.ImpersonationConfig) bool {
return cfg.UserName == "" && len(cfg.Groups) == 0 && len(cfg.Extra) == 0
}
func hasImpersonationHeaders(r *http.Request) bool {
for k := range r.Header {
if isImpersonationHeader(k) {
return true
}
}
return false
}
func isImpersonationHeader(header string) bool {
return header == transport.ImpersonateUserHeader ||
header == transport.ImpersonateUIDHeader ||
header == transport.ImpersonateGroupHeader ||
strings.HasPrefix(header, transport.ImpersonateUserExtraHeaderPrefix)
}
|
