fix: stop the job's docker socket from becoming a directory (#1215)

Fixes https://gitea.com/gitea/runner/issues/1213

Fix the DooD regression that mounts `/var/run/docker.sock` as a directory. Keep the Docker proxy available through job and post steps. Clean stale resources before opening it, then remove containers before their networks and volumes during teardown.

Use a unique filesystem probe and preserve socket ownership. Fall back to direct access when proxying is unsupported. Preserve exec output and clean up active streams and failed starts.

Add a real Docker job test for mounted socket access, post steps and resource cleanup.

---------

Co-authored-by: silverwind <[email protected]>
Reviewed-on: https://gitea.com/gitea/runner/pulls/1215
Reviewed-by: silverwind <[email protected]>
Co-authored-by: Zettat123 <[email protected]>

act/container/docker_proxy_test.go

@@ -10,18 +10,23 @@ import (
 	"bufio"
 	"bytes"
 	"context"
-	"encoding/json"
+	"errors"
+	"fmt"
 	"io"
 	"net"
 	"net/http"
+	"os"
 	"path/filepath"
+	"runtime"
+	"strconv"
 	"strings"
 	"testing"
 	"time"
 
 	cerrdefs "github.com/containerd/errdefs"
 	"github.com/moby/moby/api/types/container"
-	"github.com/moby/moby/api/types/network"
+	"github.com/moby/moby/api/types/image"
+	"github.com/moby/moby/api/types/mount"
 	"github.com/moby/moby/api/types/volume"
 	mobyclient "github.com/moby/moby/client"
 	"github.com/stretchr/testify/assert"
@@ -56,7 +61,12 @@ func daemonSocketPath(t testing.TB, cli mobyclient.APIClient) string {
 }
 
 func TestDockerProxy(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("Unix socket ownership is unavailable on Windows")
+	}
 	bodies := make(chan []byte, 8)
+	createStarted, releaseCreate := make(chan struct{}), make(chan struct{})
+	streamsDone := make(chan struct{}, 2)
 	daemonSocket := filepath.Join(shortTempDir(t), "d.sock")
 	listener, err := net.Listen("unix", daemonSocket)
 	require.NoError(t, err)
@@ -64,16 +74,33 @@ func TestDockerProxy(t *testing.T) {
 		switch {
 		case strings.HasSuffix(r.URL.Path, "/create"):
 			body, _ := io.ReadAll(r.Body)
+			if r.URL.RawQuery == "wait" {
+				close(createStarted)
+				<-releaseCreate
+			}
 			bodies <- body
 			w.WriteHeader(http.StatusCreated)
-		case strings.HasSuffix(r.URL.Path, "/start"):
+		case r.URL.Path == "/exec/detached/start" || r.URL.Path == "/exec/error/start":
+			if r.URL.Path == "/exec/error/start" {
+				w.Header().Set("Content-Type", "application/vnd.docker.raw-stream")
+				w.WriteHeader(http.StatusBadRequest)
+			}
+			_, _ = w.Write([]byte("ordinary"))
+		case rawStreamPath.MatchString(r.URL.Path) || r.URL.Path == "/session":
+			_, _ = io.Copy(io.Discard, r.Body)
 			conn, buffered, err := w.(http.Hijacker).Hijack()
 			if err != nil {
 				return
 			}
 			defer conn.Close()
-			_, _ = conn.Write([]byte("HTTP/1.1 200 OK\r\nContent-Type: application/vnd.docker.raw-stream\r\n\r\n"))
-			_, _ = io.Copy(conn, buffered)
+			if r.Header.Get("Upgrade") != "" {
+				_, _ = conn.Write([]byte("HTTP/1.1 101 Switching Protocols\r\nConnection: Upgrade\r\nUpgrade: tcp\r\n\r\nready\n"))
+			} else {
+				_, _ = conn.Write([]byte("HTTP/1.1 200 OK\r\nContent-Type: application/vnd.docker.raw-stream\r\n\r\nready\n"))
+			}
+			input, _ := io.ReadAll(buffered)
+			_, _ = conn.Write(append([]byte("final:"), input...))
+			streamsDone <- struct{}{}
 		default:
 			w.Header().Set("Api-Version", "1.47")
 			_, _ = w.Write([]byte("OK " + r.Method + " " + r.URL.Path))
@@ -83,34 +110,69 @@ func TestDockerProxy(t *testing.T) {
 	t.Cleanup(func() { _ = daemon.Close() })
 	proxy, err := StartDockerProxy(daemonSocket, shortTempDir(t), "job-1")
 	require.NoError(t, err)
-	client := &http.Client{Transport: &http.Transport{DialContext: func(ctx context.Context, _, _ string) (net.Conn, error) {
+	t.Cleanup(func() { _ = proxy.Close(context.Background()) })
+	client := &http.Client{Timeout: 5 * time.Second, Transport: &http.Transport{DialContext: func(ctx context.Context, _, _ string) (net.Conn, error) {
 		return (&net.Dialer{}).DialContext(ctx, "unix", proxy.Socket)
 	}}}
+	t.Cleanup(client.CloseIdleConnections)
+	dialProxy := func(t *testing.T) *net.UnixConn {
+		t.Helper()
+		conn, err := net.DialUnix("unix", nil, &net.UnixAddr{Name: proxy.Socket, Net: "unix"})
+		require.NoError(t, err)
+		t.Cleanup(func() { _ = conn.Close() })
+		require.NoError(t, conn.SetDeadline(time.Now().Add(5*time.Second)))
+		return conn
+	}
+	startStream := func(t *testing.T, path, upgrade string) (*net.UnixConn, *bufio.Reader) {
+		t.Helper()
+		conn := dialProxy(t)
+		_, err := fmt.Fprintf(conn, "POST %s HTTP/1.1\r\nHost: docker\r\n%sContent-Length: 2\r\n\r\n{}input", path, upgrade)
+		require.NoError(t, err)
+		reader := bufio.NewReader(conn)
+		resp, err := http.ReadResponse(reader, nil)
+		require.NoError(t, err)
+		t.Cleanup(func() {
+			_ = conn.Close()
+			_ = resp.Body.Close()
+		})
+		prefix, err := reader.ReadString('\n')
+		require.NoError(t, err)
+		require.Equal(t, "ready\n", prefix)
+		return conn, reader
+	}
 
 	t.Run("labels creates", func(t *testing.T) {
-		for path, body := range map[string]string{
-			"/v1.47/containers/create": `{"Image":"alpine","Labels":{"own":"1"}}`,
-			"/networks/create":         `{"Name":"n"}`,
-			"/volumes/create":          `{"Name":"v","labels":null}`,
+		for _, testCase := range []struct{ path, body, want string }{
+			{
+				"/v1.47/containers/create", `{"Image":"alpine","Unknown":{"enabled":true},"Labels":{"own":"1","com.gitea.runner.job":"other"}}`,
+				`{"Image":"alpine","Unknown":{"enabled":true},"Labels":{"own":"1","com.gitea.runner.job":"job-1"}}`,
+			},
+			{
+				"/networks/create", `{"Name":"n"}`,
+				`{"Name":"n","Labels":{"com.gitea.runner.job":"job-1"}}`,
+			},
+			{
+				"/volumes/create", `{"Name":"v","labels":null}`,
+				`{"Name":"v","Labels":{"com.gitea.runner.job":"job-1"}}`,
+			},
+			{
+				"/volumes/create", "",
+				`{"Labels":{"com.gitea.runner.job":"job-1"}}`,
+			},
+			{
+				"/volumes/create", "null",
+				`{"Labels":{"com.gitea.runner.job":"job-1"}}`,
+			},
+			{
+				"/volumes/create", `{"Labels":{"discard":"1"},"labels":null,"LABELS":{"own":"1"},"LABELS":{"extra":"2"}}`,
+				`{"Labels":{"own":"1","extra":"2","com.gitea.runner.job":"job-1"}}`,
+			},
 		} {
-			resp, err := client.Post("http://docker"+path, "application/json", strings.NewReader(body))
+			resp, err := client.Post("http://docker"+testCase.path, "application/json", strings.NewReader(testCase.body))
 			require.NoError(t, err)
 			resp.Body.Close()
-			assert.Equal(t, http.StatusCreated, resp.StatusCode)
-
-			var got map[string]json.RawMessage
-			require.NoError(t, json.Unmarshal(<-bodies, &got))
-			key := "Labels"
-			if _, ok := got["labels"]; ok {
-				key = "labels"
-			}
-			var labels map[string]string
-			require.NoError(t, json.Unmarshal(got[key], &labels))
-			assert.Equal(t, "job-1", labels[jobLabel], path)
-			if strings.Contains(body, "own") {
-				assert.Equal(t, "1", labels["own"])
-				assert.JSONEq(t, `"alpine"`, string(got["Image"]))
-			}
+			require.Equal(t, http.StatusCreated, resp.StatusCode)
+			assert.JSONEq(t, testCase.want, string(<-bodies), testCase.body)
 		}
 	})
 
@@ -123,40 +185,99 @@ func TestDockerProxy(t *testing.T) {
 		assert.Equal(t, "OK GET /v1.47/_ping", string(body))
 	})
 
-	t.Run("tunnels raw streams", func(t *testing.T) {
-		conn, err := net.Dial("unix", proxy.Socket)
-		require.NoError(t, err)
-		defer conn.Close()
-		_, err = conn.Write([]byte("POST /v1.47/exec/abc/start HTTP/1.1\r\nHost: docker\r\nContent-Length: 2\r\n\r\n{}ping\n"))
-		require.NoError(t, err)
+	t.Run("tunnels raw streams through stdin EOF", func(t *testing.T) {
+		for _, stream := range []struct{ path, upgrade string }{
+			{path: "/v1.47/exec/abc/start"},
+			{path: "/containers/abc/attach", upgrade: "Connection: Upgrade\r\nUpgrade: tcp\r\n"},
+		} {
+			conn, reader := startStream(t, stream.path, stream.upgrade)
+			require.NoError(t, conn.CloseWrite())
+			output, err := io.ReadAll(reader)
+			require.NoError(t, err)
+			assert.Equal(t, "final:input", string(output))
+			<-streamsDone
+		}
+	})
+
+	t.Run("detached and error responses retain keepalive label injection", func(t *testing.T) {
+		conn := dialProxy(t)
 		reader := bufio.NewReader(conn)
-		resp, err := http.ReadResponse(reader, nil)
+		for endpoint, status := range map[string]int{"detached": http.StatusOK, "error": http.StatusBadRequest} {
+			_, err := fmt.Fprintf(conn, "POST /exec/%s/start HTTP/1.1\r\nHost: docker\r\nContent-Length: 2\r\n\r\n{}", endpoint)
+			require.NoError(t, err)
+			resp, err := http.ReadResponse(reader, nil)
+			require.NoError(t, err)
+			body, err := io.ReadAll(resp.Body)
+			require.NoError(t, err)
+			require.NoError(t, resp.Body.Close())
+			assert.Equal(t, status, resp.StatusCode)
+			assert.Equal(t, "ordinary", string(body))
+			_, err = io.WriteString(conn, "POST /volumes/create HTTP/1.1\r\nHost: docker\r\nContent-Length: 0\r\n\r\n")
+			require.NoError(t, err)
+			resp, err = http.ReadResponse(reader, nil)
+			require.NoError(t, err)
+			require.NoError(t, resp.Body.Close())
+			require.Equal(t, http.StatusCreated, resp.StatusCode)
+			assert.JSONEq(t, `{"Labels":{"com.gitea.runner.job":"job-1"}}`, string(<-bodies))
+		}
+	})
+
+	t.Run("close joins streams and admitted create", func(t *testing.T) {
+		t.Cleanup(func() { close(releaseCreate) })
+		_, raw := startStream(t, "/exec/live/start", "")
+		_, upgraded := startStream(t, "/session", "Connection: Upgrade\r\nUpgrade: tcp\r\n")
+		creator := dialProxy(t)
+		_, err := io.WriteString(creator, "POST /volumes/create?wait HTTP/1.1\r\nHost: docker\r\nContent-Length: 2\r\n\r\n{}")
 		require.NoError(t, err)
-		defer resp.Body.Close()
-		assert.Equal(t, "application/vnd.docker.raw-stream", resp.Header.Get("Content-Type"))
-		echoed, err := reader.ReadString('\n')
+		<-createStarted
+		require.NoError(t, creator.CloseWrite())
+		closed := make(chan error, 1)
+		ctx, cancel := context.WithTimeout(t.Context(), 5*time.Second)
+		defer cancel()
+		go func() { closed <- proxy.Close(ctx) }()
+		for _, reader := range []*bufio.Reader{raw, upgraded} {
+			_, err := reader.ReadByte()
+			require.ErrorIs(t, err, io.EOF)
+			<-streamsDone
+		}
+		select {
+		case err := <-closed:
+			t.Fatalf("Close returned before admitted create settled: %v", err)
+		default:
+		}
+		releaseCreate <- struct{}{}
+		resp, err := http.ReadResponse(bufio.NewReader(creator), nil)
 		require.NoError(t, err)
-		assert.Equal(t, "{}ping\n", echoed)
+		require.NoError(t, resp.Body.Close())
+		require.Equal(t, http.StatusCreated, resp.StatusCode)
+		assert.JSONEq(t, `{"Labels":{"com.gitea.runner.job":"job-1"}}`, string(<-bodies))
+		require.NoError(t, <-closed)
 	})
 }
 
 func TestRemoveLabelledRemovesContainersNetworksAndVolumes(t *testing.T) {
+	containerFailure := errors.New("container removal failed")
+	listFailure := errors.New("listing failed")
+	volumeFailure := errors.New("volume removal failed")
 	ctx := context.Background()
 	filters := make(mobyclient.Filters).Add("label", jobLabel+"=job-1")
 	cli := &mockDockerClient{}
 	cli.On("ContainerList", ctx, mobyclient.ContainerListOptions{All: true, Filters: filters}).
-		Return(mobyclient.ContainerListResult{Items: []container.Summary{{ID: "c1", Names: []string{"/app"}}}}, nil)
-	cli.On("ContainerKill", ctx, "c1", mock.Anything).Return(mobyclient.ContainerKillResult{}, nil)
+		Return(mobyclient.ContainerListResult{Items: []container.Summary{{ID: "c1", Names: []string{"/app"}}}}, nil).Once()
+	cli.On("ContainerKill", ctx, "c1", mock.Anything).Return(mobyclient.ContainerKillResult{}, nil).Once()
 	cli.On("ContainerRemove", ctx, "c1", mobyclient.ContainerRemoveOptions{RemoveVolumes: true, Force: true}).
-		Return(mobyclient.ContainerRemoveResult{}, nil)
-	cli.On("NetworkList", ctx, mobyclient.NetworkListOptions{Filters: filters}).
-		Return(mobyclient.NetworkListResult{Items: []network.Summary{{ID: "n1", Name: "app_default"}}}, nil)
-	cli.On("NetworkRemove", ctx, "n1", mock.Anything).Return(mobyclient.NetworkRemoveResult{}, nil)
+		Return(mobyclient.ContainerRemoveResult{}, containerFailure).Once()
+	cli.On("NetworkList", ctx, mobyclient.NetworkListOptions{Filters: filters}).Return(mobyclient.NetworkListResult{}, listFailure).Once()
 	cli.On("VolumeList", ctx, mobyclient.VolumeListOptions{Filters: filters}).
-		Return(mobyclient.VolumeListResult{Items: []volume.Volume{{Name: "app_data"}}}, nil)
-	cli.On("VolumeRemove", ctx, "app_data", mobyclient.VolumeRemoveOptions{}).Return(mobyclient.VolumeRemoveResult{}, nil)
+		Return(mobyclient.VolumeListResult{Items: []volume.Volume{{Name: "app_data"}}}, nil).Once()
+	cli.On("VolumeRemove", ctx, "app_data", mobyclient.VolumeRemoveOptions{}).Return(mobyclient.VolumeRemoveResult{}, volumeFailure).Once()
 
-	require.NoError(t, removeLabelled(ctx, cli, "job-1"))
+	err := removeLabelled(ctx, cli, "job-1")
+	require.ErrorIs(t, err, containerFailure)
+	require.ErrorIs(t, err, listFailure)
+	require.ErrorIs(t, err, volumeFailure)
+	require.ErrorContains(t, err, "failed to remove container c1")
+	require.ErrorContains(t, err, "failed to remove volume app_data")
 	cli.AssertExpectations(t)
 }
 
@@ -168,13 +289,14 @@ func TestDockerProxyWithDaemon(t *testing.T) {
 	require.NoError(t, err)
 	defer direct.Close()
 	dir := shortTempDir(t)
-	seen, err := daemonSeesDir(ctx, dir)
+	seen, err := daemonSeesDir(ctx, direct, dir)
 	require.NoError(t, err)
 	t.Logf("daemon sees the runner's filesystem: %v", seen)
 
-	job := "proxy-test-" + t.Name()
+	job := "proxy-test-" + strconv.FormatInt(time.Now().UnixNano(), 36)
 	proxy, err := StartDockerProxy(daemonSocketPath(t, direct), dir, job)
 	require.NoError(t, err)
+	t.Cleanup(func() { _ = proxy.Close(context.Background()) })
 	viaProxy, err := mobyclient.New(mobyclient.WithHost("unix://" + proxy.Socket))
 	require.NoError(t, err)
 	defer viaProxy.Close()
@@ -212,6 +334,7 @@ func TestDockerProxyWithDaemon(t *testing.T) {
 	attached.Close()
 
 	require.NoError(t, proxy.Close(ctx))
+	require.NoError(t, RemoveDockerJobResources(ctx, job))
 	_, err = direct.ContainerInspect(ctx, created.ID, mobyclient.ContainerInspectOptions{})
 	assert.True(t, cerrdefs.IsNotFound(err))
 	_, err = direct.NetworkInspect(ctx, net.ID, mobyclient.NetworkInspectOptions{})
@@ -268,3 +391,79 @@ func BenchmarkDockerProxy(b *testing.B) {
 		})
 	}
 }
+
+type probeClient struct {
+	mobyclient.APIClient
+	create func(mobyclient.ContainerCreateOptions) (mobyclient.ContainerCreateResult, error)
+	remove func(context.Context, string, mobyclient.ContainerRemoveOptions) (mobyclient.ContainerRemoveResult, error)
+}
+
+func (c *probeClient) ImageList(context.Context, mobyclient.ImageListOptions) (mobyclient.ImageListResult, error) {
+	return mobyclient.ImageListResult{Items: []image.Summary{{ID: "probe-image"}}}, nil
+}
+
+func (c *probeClient) ContainerCreate(_ context.Context, opts mobyclient.ContainerCreateOptions) (mobyclient.ContainerCreateResult, error) {
+	return c.create(opts)
+}
+
+func (c *probeClient) ContainerRemove(ctx context.Context, id string, opts mobyclient.ContainerRemoveOptions) (mobyclient.ContainerRemoveResult, error) {
+	return c.remove(ctx, id, opts)
+}
+
+func TestDaemonSeesDir(t *testing.T) {
+	dir := t.TempDir()
+	markers := make(map[string]bool)
+	for _, testCase := range []struct {
+		name      string
+		private   bool
+		removeErr error
+	}{
+		{name: "cleanup after cancellation"},
+		{name: "private filesystem with stale marker", private: true},
+		{name: "cleanup error after cancellation", removeErr: errors.New("cleanup failed")},
+	} {
+		t.Run(testCase.name, func(t *testing.T) {
+			ctx, cancel := context.WithCancel(t.Context())
+			defer cancel()
+			daemonDir := dir
+			if testCase.private {
+				daemonDir = t.TempDir()
+				require.NoError(t, os.WriteFile(filepath.Join(daemonDir, "probe"), []byte("stale"), 0o600))
+			}
+			removed := false
+			cli := &probeClient{
+				create: func(opts mobyclient.ContainerCreateOptions) (mobyclient.ContainerCreateResult, error) {
+					require.Len(t, opts.HostConfig.Mounts, 1)
+					marker := opts.HostConfig.Mounts[0].Source
+					assert.Equal(t, mount.Mount{Type: mount.TypeBind, Source: marker, Target: "/gitea-runner-probe", ReadOnly: true}, opts.HostConfig.Mounts[0])
+					assert.False(t, markers[marker])
+					markers[marker] = true
+					info, err := os.Stat(marker)
+					require.NoError(t, err)
+					assert.True(t, info.Mode().IsRegular())
+					cancel()
+					if _, err := os.Stat(filepath.Join(daemonDir, filepath.Base(marker))); errors.Is(err, os.ErrNotExist) {
+						return mobyclient.ContainerCreateResult{}, cerrdefs.ErrInvalidArgument
+					}
+					return mobyclient.ContainerCreateResult{ID: "probe"}, nil
+				},
+				remove: func(ctx context.Context, id string, opts mobyclient.ContainerRemoveOptions) (mobyclient.ContainerRemoveResult, error) {
+					removed = true
+					assert.Equal(t, "probe", id)
+					assert.Equal(t, mobyclient.ContainerRemoveOptions{Force: true, RemoveVolumes: true}, opts)
+					require.NoError(t, ctx.Err())
+					_, bounded := ctx.Deadline()
+					assert.True(t, bounded)
+					return mobyclient.ContainerRemoveResult{}, testCase.removeErr
+				},
+			}
+			seen, err := daemonSeesDir(ctx, cli, dir)
+			require.ErrorIs(t, err, testCase.removeErr)
+			assert.Equal(t, !testCase.private && testCase.removeErr == nil, seen)
+			assert.Equal(t, !testCase.private, removed)
+			entries, err := os.ReadDir(dir)
+			require.NoError(t, err)
+			assert.Empty(t, entries)
+		})
+	}
+}