Add ability to support custom options for git-receive-pack

In order to reject pushes that are larger then the size configured by
the user on GitLab we need to support custom options for the `git -c` command.
Specifically we're going to receive receive.MaxInputSize= from the
Gitaly client. Pushes over HTTP are also protected by this setting.

7 files changed, 81 insertions, 23 deletions

diff --git a/changelogs/unreleased/rd-add-support-for-max-input-size-config.yml b/changelogs/unreleased/rd-add-support-for-max-input-size-config.yml
new file mode 100644
index 000000000..8695fa7fe
--- /dev/null
+++ b/changelogs/unreleased/rd-add-support-for-max-input-size-config.yml
@@ -0,0 +1,5 @@
+---
+title: Add ability to support custom options for git-receive-pack
+merge_request: 834
+author:
+type: added
diff --git a/internal/git/helper.go b/internal/git/helper.go
index ba4e476de..8af8511d9 100644
--- a/internal/git/helper.go
+++ b/internal/git/helper.go
@@ -59,3 +59,16 @@ func Version() (string, error) {
 
 	return ver[2], nil
 }
+
+// BuildGitOptions helps to generate options to the git command.
+// If gitOpts is not empty then its values are passed as part of
+// the "-c" option of the git command, the other values are passed along with the subcommand.
+func BuildGitOptions(gitOpts []string, otherOpts ...string) []string {
+	args := []string{}
+
+	if len(gitOpts) > 0 {
+		args = append([]string{"-c"}, gitOpts...)
+	}
+
+	return append(args, otherOpts...)
+}
diff --git a/internal/service/smarthttp/receive_pack.go b/internal/service/smarthttp/receive_pack.go
index 441793a8c..e342f051e 100644
--- a/internal/service/smarthttp/receive_pack.go
+++ b/internal/service/smarthttp/receive_pack.go
@@ -7,6 +7,7 @@ import (
 	"github.com/grpc-ecosystem/go-grpc-middleware/logging/logrus"
 	log "github.com/sirupsen/logrus"
 	"gitlab.com/gitlab-org/gitaly/internal/command"
+	"gitlab.com/gitlab-org/gitaly/internal/git"
 	"gitlab.com/gitlab-org/gitaly/internal/helper"
 
 	pb "gitlab.com/gitlab-org/gitaly-proto/go"
@@ -22,9 +23,10 @@ func (s *server) PostReceivePack(stream pb.SmartHTTPService_PostReceivePackServe
 	}
 
 	grpc_logrus.Extract(stream.Context()).WithFields(log.Fields{
-		"GlID":         req.GlId,
-		"GlRepository": req.GlRepository,
-		"GlUsername":   req.GlUsername,
+		"GlID":             req.GlId,
+		"GlRepository":     req.GlRepository,
+		"GlUsername":       req.GlUsername,
+		"GitConfigOptions": req.GitConfigOptions,
 	}).Debug("PostReceivePack")
 
 	if err := validateReceivePackRequest(req); err != nil {
@@ -53,7 +55,8 @@ func (s *server) PostReceivePack(stream pb.SmartHTTPService_PostReceivePackServe
 		return err
 	}
 
-	osCommand := exec.Command(command.GitPath(), "receive-pack", "--stateless-rpc", repoPath)
+	gitOptions := git.BuildGitOptions(req.GitConfigOptions, "receive-pack", "--stateless-rpc", repoPath)
+	osCommand := exec.Command(command.GitPath(), gitOptions...)
 	cmd, err := command.New(stream.Context(), osCommand, stdin, stdout, nil, env...)
 
 	if err != nil {
diff --git a/internal/service/ssh/receive_pack.go b/internal/service/ssh/receive_pack.go
index f4986f315..e66ec4e74 100644
--- a/internal/service/ssh/receive_pack.go
+++ b/internal/service/ssh/receive_pack.go
@@ -7,6 +7,7 @@ import (
 	"github.com/grpc-ecosystem/go-grpc-middleware/logging/logrus"
 	log "github.com/sirupsen/logrus"
 	"gitlab.com/gitlab-org/gitaly/internal/command"
+	"gitlab.com/gitlab-org/gitaly/internal/git"
 	"gitlab.com/gitlab-org/gitaly/internal/helper"
 
 	pb "gitlab.com/gitlab-org/gitaly-proto/go"
@@ -22,9 +23,10 @@ func (s *server) SSHReceivePack(stream pb.SSHService_SSHReceivePackServer) error
 	}
 
 	grpc_logrus.Extract(stream.Context()).WithFields(log.Fields{
-		"GlID":         req.GlId,
-		"GlRepository": req.GlRepository,
-		"GlUsername":   req.GlUsername,
+		"GlID":             req.GlId,
+		"GlRepository":     req.GlRepository,
+		"GlUsername":       req.GlUsername,
+		"GitConfigOptions": req.GitConfigOptions,
 	}).Debug("SSHReceivePack")
 
 	if err = validateFirstReceivePackRequest(req); err != nil {
@@ -55,7 +57,8 @@ func (s *server) SSHReceivePack(stream pb.SSHService_SSHReceivePackServer) error
 		return err
 	}
 
-	osCommand := exec.Command(command.GitPath(), "receive-pack", repoPath)
+	gitOptions := git.BuildGitOptions(req.GitConfigOptions, "receive-pack", repoPath)
+	osCommand := exec.Command(command.GitPath(), gitOptions...)
 	cmd, err := command.New(stream.Context(), osCommand, stdin, stdout, stderr, env...)
 
 	if err != nil {
diff --git a/internal/service/ssh/receive_pack_test.go b/internal/service/ssh/receive_pack_test.go
index 9aa6754eb..c3e1d24ee 100644
--- a/internal/service/ssh/receive_pack_test.go
+++ b/internal/service/ssh/receive_pack_test.go
@@ -3,6 +3,7 @@ package ssh
 import (
 	"bytes"
 	"fmt"
+	"io/ioutil"
 	"os"
 	"os/exec"
 	"path"
@@ -13,6 +14,7 @@ import (
 	"github.com/golang/protobuf/jsonpb"
 	"github.com/stretchr/testify/require"
 
+	"gitlab.com/gitlab-org/gitaly/internal/git"
 	"gitlab.com/gitlab-org/gitaly/internal/testhelper"
 
 	pb "gitlab.com/gitlab-org/gitaly-proto/go"
@@ -79,7 +81,15 @@ func TestReceivePackPushSuccess(t *testing.T) {
 	server, serverSocketPath := runSSHServer(t)
 	defer server.Stop()
 
-	lHead, rHead, err := testCloneAndPush(t, serverSocketPath, testRepo.GetStorageName(), "1")
+	lHead, rHead, err := testCloneAndPush(t, serverSocketPath, pushParams{storageName: testRepo.GetStorageName(), glID: "1"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if strings.Compare(lHead, rHead) != 0 {
+		t.Errorf("local and remote head not equal. push failed: %q != %q", lHead, rHead)
+	}
+
+	lHead, rHead, err = testCloneAndPush(t, serverSocketPath, pushParams{storageName: testRepo.GetStorageName(), glID: "1", gitConfigOptions: []string{"receive.MaxInputSize=10000"}})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -92,17 +102,29 @@ func TestReceivePackPushFailure(t *testing.T) {
 	server, serverSocketPath := runSSHServer(t)
 	defer server.Stop()
 
-	_, _, err := testCloneAndPush(t, serverSocketPath, "foobar", "1")
+	_, _, err := testCloneAndPush(t, serverSocketPath, pushParams{storageName: "foobar", glID: "1"})
 	if err == nil {
 		t.Errorf("local and remote head equal. push did not fail")
 	}
-	_, _, err = testCloneAndPush(t, serverSocketPath, testRepo.GetStorageName(), "")
+
+	_, _, err = testCloneAndPush(t, serverSocketPath, pushParams{storageName: testRepo.GetStorageName(), glID: ""})
 	if err == nil {
 		t.Errorf("local and remote head equal. push did not fail")
 	}
+
+	currentGitVersion, _ := git.Version()
+
+	// receive.MaxInputSize is only available since Git 2.11.0
+	// Skip this test from the job that uses Git 2.9.0
+	if currentGitVersion != "2.9.0" {
+		_, _, err = testCloneAndPush(t, serverSocketPath, pushParams{storageName: testRepo.GetStorageName(), glID: "1", gitConfigOptions: []string{"receive.MaxInputSize=1"}})
+		if err == nil {
+			t.Errorf("local and remote head equal. push did not fail")
+		}
+	}
 }
 
-func testCloneAndPush(t *testing.T, serverSocketPath string, storageName, glID string) (string, string, error) {
+func testCloneAndPush(t *testing.T, serverSocketPath string, params pushParams) (string, string, error) {
 	storagePath := testhelper.GitlabTestStoragePath()
 	tempRepo := "gitlab-test-ssh-receive-pack.git"
 	testRepoPath := path.Join(storagePath, testRepo.GetRelativePath())
@@ -124,12 +146,13 @@ func testCloneAndPush(t *testing.T, serverSocketPath string, storageName, glID s
 
 	makeCommit(t, localRepoPath)
 
-	pbTempRepo := &pb.Repository{StorageName: storageName, RelativePath: tempRepo}
+	pbTempRepo := &pb.Repository{StorageName: params.storageName, RelativePath: tempRepo}
 	pbMarshaler := &jsonpb.Marshaler{}
 	payload, err := pbMarshaler.MarshalToString(&pb.SSHReceivePackRequest{
-		Repository:   pbTempRepo,
-		GlRepository: pbTempRepo.GetRelativePath(),
-		GlId:         glID,
+		Repository:       pbTempRepo,
+		GlRepository:     pbTempRepo.GetRelativePath(),
+		GlId:             params.glID,
+		GitConfigOptions: params.gitConfigOptions,
 	})
 	require.NoError(t, err)
 
@@ -159,6 +182,11 @@ func makeCommit(t *testing.T, localRepoPath string) ([]byte, []byte, bool) {
 	commitMsg := fmt.Sprintf("Testing ReceivePack RPC around %d", time.Now().Unix())
 	committerName := "Scrooge McDuck"
 	committerEmail := "scrooge@mcduck.com"
+	newFilePath := localRepoPath + "/foo.txt"
+
+	// Create a tiny file and add it to the index
+	require.NoError(t, ioutil.WriteFile(newFilePath, []byte("foo bar"), 0644))
+	testhelper.MustRunCommand(t, nil, "git", "-C", localRepoPath, "add", ".")
 
 	// The latest commit ID on the remote repo
 	oldHead := bytes.TrimSpace(testhelper.MustRunCommand(t, nil, "git", "-C", localRepoPath, "rev-parse", "master"))
@@ -166,7 +194,7 @@ func makeCommit(t *testing.T, localRepoPath string) ([]byte, []byte, bool) {
 	testhelper.MustRunCommand(t, nil, "git", "-C", localRepoPath,
 		"-c", fmt.Sprintf("user.name=%s", committerName),
 		"-c", fmt.Sprintf("user.email=%s", committerEmail),
-		"commit", "--allow-empty", "-m", commitMsg)
+		"commit", "-m", commitMsg)
 	if t.Failed() {
 		return nil, nil, false
 	}
@@ -184,3 +212,9 @@ func drainPostReceivePackResponse(stream pb.SSH_SSHReceivePackClient) error {
 	}
 	return err
 }
+
+type pushParams struct {
+	storageName      string
+	glID             string
+	gitConfigOptions []string
+}
diff --git a/vendor/gitlab.com/gitlab-org/gitaly-proto/go/VERSION b/vendor/gitlab.com/gitlab-org/gitaly-proto/go/VERSION
index e23e3fd29..5af665a17 100644
--- a/vendor/gitlab.com/gitlab-org/gitaly-proto/go/VERSION
+++ b/vendor/gitlab.com/gitlab-org/gitaly-proto/go/VERSION
@@ -1 +1 @@
-0.112.0
+0.111.0
diff --git a/vendor/vendor.json b/vendor/vendor.json
index ef4c8deb8..376d4a1b1 100644
--- a/vendor/vendor.json
+++ b/vendor/vendor.json
@@ -201,12 +201,12 @@
 			"revisionTime": "2017-12-31T12:27:32Z"
 		},
 		{
-			"checksumSHA1": "oUra5duKbNfxA8e++b+QbLQYYXU=",
+			"checksumSHA1": "+GRNcdfnAibgtDObICxZIFk7i9Q=",
 			"path": "gitlab.com/gitlab-org/gitaly-proto/go",
-			"revision": "e3a5c0a6da1c62f406f6b74b281dad43f8b74ea5",
-			"revisionTime": "2018-08-02T15:59:47Z",
-			"version": "v0.112.0",
-			"versionExact": "v0.112.0"
+			"revision": "b26cda22da41c708d18be78c519a38810acfdc80",
+			"revisionTime": "2018-07-31T12:04:23Z",
+			"version": "v0.111.0",
+			"versionExact": "v0.111.0"
 		},
 		{
 			"checksumSHA1": "nqWNlnMmVpt628zzvyo6Yv2CX5Q=",