authorize: refactor logAuthorizeCheck() (#5576)

Currently, policy evaluation and authorize logging are coupled to the
Envoy CheckRequest proto message (part of the ext_authz API). In the
context of ssh proxy authentication, we won't have a CheckRequest.
Instead, let's make the existing evaluator.Request type the source of
truth for the authorize log fields.

This way, whether we populate the evaluator.Request struct from an
ext_authz request or from an ssh proxy request, we can use the same
logAuthorizeCheck() method for logging.

Add some additional fields to evaluator.RequestHTTP for the authorize
log fields that are not currently represented in this struct.

authorize/grpc.go

@@ -2,26 +2,23 @@ package authorize
 
 import (
 	"context"
-	"encoding/pem"
 	"errors"
 	"fmt"
 	"io"
 	"net/http"
-	"net/url"
 	"strings"
 
 	envoy_service_auth_v3 "github.com/envoyproxy/go-control-plane/envoy/service/auth/v3"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
-	"google.golang.org/protobuf/types/known/structpb"
 
+	"github.com/pomerium/pomerium/authorize/checkrequest"
 	"github.com/pomerium/pomerium/authorize/evaluator"
 	"github.com/pomerium/pomerium/config"
 	"github.com/pomerium/pomerium/config/envoyconfig"
 	"github.com/pomerium/pomerium/internal/httputil"
 	"github.com/pomerium/pomerium/internal/log"
 	"github.com/pomerium/pomerium/internal/sessions"
-	"github.com/pomerium/pomerium/internal/urlutil"
 	"github.com/pomerium/pomerium/pkg/contextutil"
 	"github.com/pomerium/pomerium/pkg/grpc/databroker"
 	"github.com/pomerium/pomerium/pkg/grpc/user"
@@ -80,7 +77,7 @@ func (a *Authorize) Check(ctx context.Context, in *envoy_service_auth_v3.CheckRe
 	if err != nil {
 		log.Ctx(ctx).Error().Err(err).Str("request-id", requestID).Msg("grpc check ext_authz_error")
 	}
-	a.logAuthorizeCheck(ctx, in, res, s, u)
+	a.logAuthorizeCheck(ctx, req, res, s, u)
 	return resp, err
 }
 
@@ -138,18 +135,10 @@ func (a *Authorize) getEvaluatorRequestFromCheckRequest(
 	ctx context.Context,
 	in *envoy_service_auth_v3.CheckRequest,
 ) (*evaluator.Request, error) {
-	requestURL := getCheckRequestURL(in)
 	attrs := in.GetAttributes()
-	clientCertMetadata := attrs.GetMetadataContext().GetFilterMetadata()["com.pomerium.client-certificate-info"]
 	req := &evaluator.Request{
 		IsInternal: envoyconfig.ExtAuthzContextExtensionsIsInternal(attrs.GetContextExtensions()),
-		HTTP: evaluator.NewRequestHTTP(
-			attrs.GetRequest().GetHttp().GetMethod(),
-			requestURL,
-			getCheckRequestHeaders(in),
-			getClientCertificateInfo(ctx, clientCertMetadata),
-			attrs.GetSource().GetAddress().GetSocketAddress().GetAddress(),
-		),
+		HTTP:       evaluator.RequestHTTPFromCheckRequest(ctx, in),
 	}
 	req.Policy = a.getMatchingPolicy(envoyconfig.ExtAuthzContextExtensionsRouteID(attrs.GetContextExtensions()))
 	return req, nil
@@ -185,7 +174,7 @@ func (a *Authorize) withQuerierForCheckRequest(ctx context.Context) context.Cont
 
 func getHTTPRequestFromCheckRequest(req *envoy_service_auth_v3.CheckRequest) *http.Request {
 	hattrs := req.GetAttributes().GetRequest().GetHttp()
-	u := getCheckRequestURL(req)
+	u := checkrequest.GetURL(req)
 	hreq := &http.Request{
 		Method:     hattrs.GetMethod(),
 		URL:        &u,
@@ -208,57 +197,3 @@ func getCheckRequestHeaders(req *envoy_service_auth_v3.CheckRequest) map[string]
 	}
 	return hdrs
 }
-
-func getCheckRequestURL(req *envoy_service_auth_v3.CheckRequest) url.URL {
-	h := req.GetAttributes().GetRequest().GetHttp()
-	u := url.URL{
-		Scheme: h.GetScheme(),
-		Host:   h.GetHost(),
-	}
-	u.Host = urlutil.GetDomainsForURL(&u, false)[0]
-	// envoy sends the query string as part of the path
-	path := h.GetPath()
-	if idx := strings.Index(path, "?"); idx != -1 {
-		u.RawPath, u.RawQuery = path[:idx], path[idx+1:]
-		u.RawQuery = u.Query().Encode()
-	} else {
-		u.RawPath = path
-	}
-	u.Path, _ = url.PathUnescape(u.RawPath)
-	return u
-}
-
-// getClientCertificateInfo translates from the client certificate Envoy
-// metadata to the ClientCertificateInfo type.
-func getClientCertificateInfo(
-	ctx context.Context, metadata *structpb.Struct,
-) evaluator.ClientCertificateInfo {
-	var c evaluator.ClientCertificateInfo
-	if metadata == nil {
-		return c
-	}
-	c.Presented = metadata.Fields["presented"].GetBoolValue()
-	escapedChain := metadata.Fields["chain"].GetStringValue()
-	if escapedChain == "" {
-		// No validated client certificate.
-		return c
-	}
-
-	chain, err := url.QueryUnescape(escapedChain)
-	if err != nil {
-		log.Ctx(ctx).Error().Str("chain", escapedChain).Err(err).
-			Msg(`received unexpected client certificate "chain" value`)
-		return c
-	}
-
-	// Split the chain into the leaf and any intermediate certificates.
-	p, rest := pem.Decode([]byte(chain))
-	if p == nil {
-		log.Ctx(ctx).Error().Str("chain", escapedChain).
-			Msg(`received unexpected client certificate "chain" value (no PEM block found)`)
-		return c
-	}
-	c.Leaf = string(pem.EncodeToMemory(p))
-	c.Intermediates = string(rest)
-	return c
-}