proto: Drop deprecated `http_host` field in FindRemoteRootRef RPC

The `http_host` field was added in order to avoid DNS rebinding attacks.
Callers would send us both the pre-resolved URL and the hostname so that
we would directly connect to the pre-resolved address, but still be able
to set the HTTP `Host` header as expected. This approach was replaced
in favor of the new `resolved_address` field, where Gitaly receives the
un-resolved URL and resolved IP address so that it can perform the
mapping internally.

We have thus deprecated the `http_host` field via cbdc529000 (proto:
Deprecate `http_host` field, 2022-09-30). Remove the field for the
FindRemoteRootRef RPC.

Changelog: removed

4 files changed, 12 insertions, 54 deletions

diff --git a/internal/gitaly/service/remote/find_remote_root_ref.go b/internal/gitaly/service/remote/find_remote_root_ref.go
index 40fdb2e32..c74d5007d 100644
--- a/internal/gitaly/service/remote/find_remote_root_ref.go
+++ b/internal/gitaly/service/remote/find_remote_root_ref.go
@@ -37,13 +37,6 @@ func (s *server) findRemoteRootRefCmd(ctx context.Context, request *gitalypb.Fin
 			Value: "Authorization: " + authHeader,
 		})
 	}
-	//nolint:staticcheck
-	if host := request.GetHttpHost(); host != "" {
-		config = append(config, git.ConfigPair{
-			Key:   fmt.Sprintf("http.%s.extraHeader", request.RemoteUrl),
-			Value: "Host: " + host,
-		})
-	}
 
 	return s.gitCmdFactory.New(ctx, request.Repository,
 		git.Command{
diff --git a/internal/gitaly/service/remote/find_remote_root_ref_test.go b/internal/gitaly/service/remote/find_remote_root_ref_test.go
index 196a8fabc..fedc49bea 100644
--- a/internal/gitaly/service/remote/find_remote_root_ref_test.go
+++ b/internal/gitaly/service/remote/find_remote_root_ref_test.go
@@ -2,7 +2,6 @@ package remote
 
 import (
 	"fmt"
-	"net/http"
 	"path/filepath"
 	"testing"
 
@@ -81,13 +80,12 @@ func TestFindRemoteRootRef(t *testing.T) {
 		{
 			desc: "successful",
 			setup: func(t *testing.T) setupData {
-				host := "example.com"
 				secret := "mysecret"
 
 				_, remoteRepoPath := gittest.CreateRepository(t, ctx, cfg)
 				gittest.WriteCommit(t, cfg, remoteRepoPath, gittest.WithBranch("main"))
 
-				port := gittest.HTTPServer(t, ctx, gitCmdFactory, remoteRepoPath, newGitRequestValidationMiddleware(host, secret))
+				port := gittest.HTTPServer(t, ctx, gitCmdFactory, remoteRepoPath, nil)
 				originURL := fmt.Sprintf("http://127.0.0.1:%d/%s", port, filepath.Base(remoteRepoPath))
 
 				return setupData{
@@ -95,7 +93,6 @@ func TestFindRemoteRootRef(t *testing.T) {
 						Repository:              localRepo,
 						RemoteUrl:               originURL,
 						HttpAuthorizationHeader: secret,
-						HttpHost:                host,
 					},
 					expectedResponse: &gitalypb.FindRemoteRootRefResponse{
 						Ref: "main",
@@ -144,21 +141,6 @@ func TestFindRemoteRootRef(t *testing.T) {
 	}
 }
 
-func newGitRequestValidationMiddleware(host, secret string) func(http.ResponseWriter, *http.Request, http.Handler) {
-	return func(w http.ResponseWriter, r *http.Request, next http.Handler) {
-		if r.Host != host {
-			http.Error(w, "No Host", http.StatusBadRequest)
-			return
-		}
-		if r.Header.Get("Authorization") != secret {
-			http.Error(w, "Unauthorized", http.StatusUnauthorized)
-			return
-		}
-
-		next.ServeHTTP(w, r)
-	}
-}
-
 func TestServer_findRemoteRootRefCmd(t *testing.T) {
 	t.Parallel()
 
diff --git a/proto/go/gitalypb/remote.pb.go b/proto/go/gitalypb/remote.pb.go
index 082191a8e..10d95dd97 100644
--- a/proto/go/gitalypb/remote.pb.go
+++ b/proto/go/gitalypb/remote.pb.go
@@ -299,13 +299,6 @@ type FindRemoteRootRefRequest struct {
 	// HttpAuthorizationHeader is the HTTP header which should be added to the
 	// request in order to authenticate against the repository.
 	HttpAuthorizationHeader string `protobuf:"bytes,4,opt,name=http_authorization_header,json=httpAuthorizationHeader,proto3" json:"http_authorization_header,omitempty"`
-	// HttpHost is the hostname of the remote repository. Use this when the
-	// URL hostname has already been resolved to an IP address to prevent DNS
-	// rebinding. This is deprecated as we will be using resolved_address
-	// going forward.
-	//
-	// Deprecated: Marked as deprecated in remote.proto.
-	HttpHost string `protobuf:"bytes,5,opt,name=http_host,json=httpHost,proto3" json:"http_host,omitempty"`
 	// ResolvedAddress holds the resolved IP address of the remote_url. This is
 	// used to avoid DNS rebinding by mapping the url to the resolved address.
 	// Only IPv4 dotted decimal ("192.0.2.1"), IPv6 ("2001:db8::68"), or IPv4-mapped
@@ -368,14 +361,6 @@ func (x *FindRemoteRootRefRequest) GetHttpAuthorizationHeader() string {
 	return ""
 }
 
-// Deprecated: Marked as deprecated in remote.proto.
-func (x *FindRemoteRootRefRequest) GetHttpHost() string {
-	if x != nil {
-		return x.HttpHost
-	}
-	return ""
-}
-
 func (x *FindRemoteRootRefRequest) GetResolvedAddress() string {
 	if x != nil {
 		return x.ResolvedAddress
@@ -571,7 +556,7 @@ var file_remote_proto_rawDesc = []byte{
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@@ -582,13 +567,12 @@ var file_remote_proto_rawDesc = []byte{
 	0x72, 0x6c, 0x12, 0x3a, 0x0a, 0x19, 0x68, 0x74, 0x74, 0x70, 0x5f, 0x61, 0x75, 0x74, 0x68, 0x6f,
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diff --git a/proto/remote.proto b/proto/remote.proto
index 4b91efb18..fe8e1fa6a 100644
--- a/proto/remote.proto
+++ b/proto/remote.proto
@@ -127,11 +127,6 @@ message FindRemoteRootRefRequest {
   // HttpAuthorizationHeader is the HTTP header which should be added to the
   // request in order to authenticate against the repository.
   string http_authorization_header = 4;
-  // HttpHost is the hostname of the remote repository. Use this when the
-  // URL hostname has already been resolved to an IP address to prevent DNS
-  // rebinding. This is deprecated as we will be using resolved_address
-  // going forward.
-  string http_host = 5 [deprecated=true];
   // ResolvedAddress holds the resolved IP address of the remote_url. This is
   // used to avoid DNS rebinding by mapping the url to the resolved address.
   // Only IPv4 dotted decimal ("192.0.2.1"), IPv6 ("2001:db8::68"), or IPv4-mapped
@@ -142,6 +137,10 @@ message FindRemoteRootRefRequest {
 
   reserved 2;
   reserved "remote";
+
+  // HttpHost has been removed in favor of ResolvedAddress.
+  reserved 5;
+  reserved "http_host";
 }
 
 // FindRemoteRootRefResponse represents the response for the FindRemoteRootRef