Merge branch 'main' into fix/repo-url-validation

Reviewed-on: #93

internal/config/config.go

@@ -52,6 +52,7 @@ type Config struct {
 	MetricsUsername string
 	MetricsPassword string
 	SessionSecret   string
+	CORSOrigins     string
 	params          *Params
 	log             *slog.Logger
 }
@@ -102,6 +103,7 @@ func setupViper(name string) {
 	viper.SetDefault("METRICS_USERNAME", "")
 	viper.SetDefault("METRICS_PASSWORD", "")
 	viper.SetDefault("SESSION_SECRET", "")
+	viper.SetDefault("CORS_ORIGINS", "")
 }
 
 func buildConfig(log *slog.Logger, params *Params) (*Config, error) {
@@ -136,6 +138,7 @@ func buildConfig(log *slog.Logger, params *Params) (*Config, error) {
 		MetricsUsername: viper.GetString("METRICS_USERNAME"),
 		MetricsPassword: viper.GetString("METRICS_PASSWORD"),
 		SessionSecret:   viper.GetString("SESSION_SECRET"),
+		CORSOrigins:     viper.GetString("CORS_ORIGINS"),
 		params:          params,
 		log:             log,
 	}

internal/docker/client.go

@@ -17,6 +17,7 @@ import (
 	"github.com/docker/docker/api/types"
 	"github.com/docker/docker/api/types/container"
 	"github.com/docker/docker/api/types/filters"
+	"github.com/docker/docker/api/types/image"
 	"github.com/docker/docker/api/types/mount"
 	"github.com/docker/docker/api/types/network"
 	"github.com/docker/docker/client"
@@ -739,6 +740,20 @@ func (c *Client) connect(ctx context.Context) error {
 	return nil
 }
 
+// RemoveImage removes a Docker image by ID or tag.
+// It returns nil if the image was successfully removed or does not exist.
+func (c *Client) RemoveImage(ctx context.Context, imageID string) error {
+	_, err := c.docker.ImageRemove(ctx, imageID, image.RemoveOptions{
+		Force:         true,
+		PruneChildren: true,
+	})
+	if err != nil && !client.IsErrNotFound(err) {
+		return fmt.Errorf("failed to remove image %s: %w", imageID, err)
+	}
+
+	return nil
+}
+
 func (c *Client) close() error {
 	if c.docker != nil {
 		err := c.docker.Close()

internal/handlers/api.go

@@ -218,6 +218,15 @@ func (h *Handlers) HandleAPICreateApp() http.HandlerFunc {
 			return
 		}
 
+		repoURLErr := validateRepoURL(req.RepoURL)
+		if repoURLErr != nil {
+			h.respondJSON(writer, request,
+				map[string]string{"error": "invalid repository URL: " + repoURLErr.Error()},
+				http.StatusBadRequest)
+
+			return
+		}
+
 		createdApp, createErr := h.appService.CreateApp(request.Context(), app.CreateAppInput{
 			Name:           req.Name,
 			RepoURL:        req.RepoURL,

internal/handlers/app.go

@@ -77,6 +77,14 @@ func (h *Handlers) HandleAppCreate() http.HandlerFunc { //nolint:funlen // valid
 			return
 		}
 
+		repoURLErr := validateRepoURL(repoURL)
+		if repoURLErr != nil {
+			data["Error"] = "Invalid repository URL: " + repoURLErr.Error()
+			h.renderTemplate(writer, tmpl, "app_new.html", data)
+
+			return
+		}
+
 		if branch == "" {
 			branch = "main"
 		}
@@ -225,6 +233,17 @@ func (h *Handlers) HandleAppUpdate() http.HandlerFunc { //nolint:funlen // valid
 			return
 		}
 
+		repoURLErr := validateRepoURL(request.FormValue("repo_url"))
+		if repoURLErr != nil {
+			data := h.addGlobals(map[string]any{
+				"App":   application,
+				"Error": "Invalid repository URL: " + repoURLErr.Error(),
+			}, request)
+			_ = tmpl.ExecuteTemplate(writer, "app_edit.html", data)
+
+			return
+		}
+
 		application.Name = newName
 		application.RepoURL = request.FormValue("repo_url")
 		application.Branch = request.FormValue("branch")

internal/handlers/repo_url_validation.go

@@ -0,0 +1,67 @@
+package handlers
+
+import (
+	"errors"
+	"net/url"
+	"regexp"
+	"strings"
+)
+
+// Repo URL validation errors.
+var (
+	errRepoURLEmpty   = errors.New("repository URL must not be empty")
+	errRepoURLScheme  = errors.New("file:// URLs are not allowed for security reasons")
+	errRepoURLInvalid = errors.New("repository URL must use https://, http://, ssh://, git://, or git@host:path format")
+	errRepoURLNoHost  = errors.New("repository URL must include a host")
+	errRepoURLNoPath  = errors.New("repository URL must include a path")
+)
+
+// scpLikeRepoRe matches SCP-like git URLs: git@host:path (e.g. git@github.com:user/repo.git).
+// Only the "git" user is allowed, as that is the standard for SSH deploy keys.
+var scpLikeRepoRe = regexp.MustCompile(`^git@[a-zA-Z0-9._-]+:.+$`)
+
+// validateRepoURL checks that the given repository URL is valid and uses an allowed scheme.
+func validateRepoURL(repoURL string) error {
+	if strings.TrimSpace(repoURL) == "" {
+		return errRepoURLEmpty
+	}
+
+	// Reject path traversal in any URL format
+	if strings.Contains(repoURL, "..") {
+		return errRepoURLInvalid
+	}
+
+	// Check for SCP-like git URLs first (git@host:path)
+	if scpLikeRepoRe.MatchString(repoURL) {
+		return nil
+	}
+
+	// Reject file:// explicitly
+	if strings.HasPrefix(strings.ToLower(repoURL), "file://") {
+		return errRepoURLScheme
+	}
+
+	// Parse as standard URL
+	parsed, err := url.Parse(repoURL)
+	if err != nil {
+		return errRepoURLInvalid
+	}
+
+	// Must have a recognized scheme
+	switch strings.ToLower(parsed.Scheme) {
+	case "https", "http", "ssh", "git":
+		// OK
+	default:
+		return errRepoURLInvalid
+	}
+
+	if parsed.Host == "" {
+		return errRepoURLNoHost
+	}
+
+	if parsed.Path == "" || parsed.Path == "/" {
+		return errRepoURLNoPath
+	}
+
+	return nil
+}

internal/handlers/repo_url_validation_test.go

@@ -0,0 +1,56 @@
+package handlers
+
+import "testing"
+
+func TestValidateRepoURL(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name    string
+		url     string
+		wantErr bool
+	}{
+		// Valid URLs
+		{name: "https URL", url: "https://github.com/user/repo.git", wantErr: false},
+		{name: "http URL", url: "http://github.com/user/repo.git", wantErr: false},
+		{name: "ssh URL", url: "ssh://git@github.com/user/repo.git", wantErr: false},
+		{name: "git URL", url: "git://github.com/user/repo.git", wantErr: false},
+		{name: "SCP-like URL", url: "git@github.com:user/repo.git", wantErr: false},
+		{name: "SCP-like with dots", url: "git@git.example.com:org/repo.git", wantErr: false},
+		{name: "https without .git", url: "https://github.com/user/repo", wantErr: false},
+		{name: "https with port", url: "https://git.example.com:8443/user/repo.git", wantErr: false},
+
+		// Invalid URLs
+		{name: "empty string", url: "", wantErr: true},
+		{name: "whitespace only", url: "   ", wantErr: true},
+		{name: "file URL", url: "file:///etc/passwd", wantErr: true},
+		{name: "file URL uppercase", url: "FILE:///etc/passwd", wantErr: true},
+		{name: "bare path", url: "/some/local/path", wantErr: true},
+		{name: "relative path", url: "../repo", wantErr: true},
+		{name: "just a word", url: "notaurl", wantErr: true},
+		{name: "ftp URL", url: "ftp://example.com/repo.git", wantErr: true},
+		{name: "no host https", url: "https:///path", wantErr: true},
+		{name: "no path https", url: "https://github.com", wantErr: true},
+		{name: "no path https trailing slash", url: "https://github.com/", wantErr: true},
+		{name: "SCP-like non-git user", url: "root@github.com:user/repo.git", wantErr: true},
+		{name: "SCP-like arbitrary user", url: "admin@github.com:user/repo.git", wantErr: true},
+		{name: "path traversal SCP", url: "git@github.com:../../etc/passwd", wantErr: true},
+		{name: "path traversal https", url: "https://github.com/user/../../../etc/passwd", wantErr: true},
+		{name: "path traversal in middle", url: "https://github.com/user/repo/../secret", wantErr: true},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			t.Parallel()
+
+			err := validateRepoURL(tc.url)
+			if tc.wantErr && err == nil {
+				t.Errorf("validateRepoURL(%q) = nil, want error", tc.url)
+			}
+
+			if !tc.wantErr && err != nil {
+				t.Errorf("validateRepoURL(%q) = %v, want nil", tc.url, err)
+			}
+		})
+	}
+}

internal/middleware/cors_test.go

@@ -0,0 +1,81 @@
+package middleware //nolint:testpackage // tests internal CORS behavior
+
+import (
+	"log/slog"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"git.eeqj.de/sneak/upaas/internal/config"
+)
+
+//nolint:gosec // test credentials
+func newCORSTestMiddleware(corsOrigins string) *Middleware {
+	return &Middleware{
+		log: slog.Default(),
+		params: &Params{
+			Config: &config.Config{
+				CORSOrigins:   corsOrigins,
+				SessionSecret: "test-secret-32-bytes-long-enough",
+			},
+		},
+	}
+}
+
+func TestCORS_NoOriginsConfigured_NoCORSHeaders(t *testing.T) {
+	t.Parallel()
+
+	m := newCORSTestMiddleware("")
+	handler := m.CORS()(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusOK)
+	}))
+
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	req.Header.Set("Origin", "https://evil.com")
+
+	rec := httptest.NewRecorder()
+	handler.ServeHTTP(rec, req)
+
+	assert.Empty(t, rec.Header().Get("Access-Control-Allow-Origin"),
+		"expected no CORS headers when no origins configured")
+}
+
+func TestCORS_OriginsConfigured_AllowsMatchingOrigin(t *testing.T) {
+	t.Parallel()
+
+	m := newCORSTestMiddleware("https://app.example.com,https://other.example.com")
+	handler := m.CORS()(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusOK)
+	}))
+
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	req.Header.Set("Origin", "https://app.example.com")
+
+	rec := httptest.NewRecorder()
+	handler.ServeHTTP(rec, req)
+
+	assert.Equal(t, "https://app.example.com",
+		rec.Header().Get("Access-Control-Allow-Origin"))
+	assert.Equal(t, "true",
+		rec.Header().Get("Access-Control-Allow-Credentials"))
+}
+
+func TestCORS_OriginsConfigured_RejectsNonMatchingOrigin(t *testing.T) {
+	t.Parallel()
+
+	m := newCORSTestMiddleware("https://app.example.com")
+	handler := m.CORS()(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusOK)
+	}))
+
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	req.Header.Set("Origin", "https://evil.com")
+
+	rec := httptest.NewRecorder()
+	handler.ServeHTTP(rec, req)
+
+	assert.Empty(t, rec.Header().Get("Access-Control-Allow-Origin"),
+		"expected no CORS headers for non-matching origin")
+}

internal/middleware/middleware.go

@@ -177,17 +177,48 @@ func realIP(r *http.Request) string {
 }
 
 // CORS returns CORS middleware.
+// When UPAAS_CORS_ORIGINS is empty (default), no CORS headers are sent
+// (same-origin only). When configured, only the specified origins are
+// allowed and credentials (cookies) are permitted.
 func (m *Middleware) CORS() func(http.Handler) http.Handler {
+	origins := parseCORSOrigins(m.params.Config.CORSOrigins)
+
+	// No origins configured — no CORS headers (same-origin policy).
+	if len(origins) == 0 {
+		return func(next http.Handler) http.Handler {
+			return next
+		}
+	}
+
 	return cors.Handler(cors.Options{
-		AllowedOrigins:   []string{"*"},
+		AllowedOrigins:   origins,
 		AllowedMethods:   []string{"GET", "POST", "PUT", "DELETE", "OPTIONS"},
 		AllowedHeaders:   []string{"Accept", "Authorization", "Content-Type", "X-CSRF-Token"},
 		ExposedHeaders:   []string{"Link"},
-		AllowCredentials: false,
+		AllowCredentials: true,
 		MaxAge:           corsMaxAge,
 	})
 }
 
+// parseCORSOrigins splits a comma-separated origin string into a slice,
+// trimming whitespace. Returns nil if the input is empty.
+func parseCORSOrigins(raw string) []string {
+	if raw == "" {
+		return nil
+	}
+
+	parts := strings.Split(raw, ",")
+	origins := make([]string, 0, len(parts))
+
+	for _, p := range parts {
+		if o := strings.TrimSpace(p); o != "" {
+			origins = append(origins, o)
+		}
+	}
+
+	return origins
+}
+
 // MetricsAuth returns basic auth middleware for metrics endpoint.
 func (m *Middleware) MetricsAuth() func(http.Handler) http.Handler {
 	if m.params.Config.MetricsUsername == "" {
@@ -235,9 +266,9 @@ func (m *Middleware) CSRF() func(http.Handler) http.Handler {
 // loginRateLimit configures the login rate limiter.
 const (
 	loginRateLimit      = rate.Limit(5.0 / 60.0) // 5 requests per 60 seconds
-	loginBurst          = 5                       // allow burst of 5
-	limiterExpiry       = 10 * time.Minute        // evict entries not seen in 10 minutes
-	limiterCleanupEvery = 1 * time.Minute         // sweep interval
+	loginBurst          = 5                      // allow burst of 5
+	limiterExpiry       = 10 * time.Minute       // evict entries not seen in 10 minutes
+	limiterCleanupEvery = 1 * time.Minute        // sweep interval
 )
 
 // ipLimiterEntry stores a rate limiter with its last-seen timestamp.
@@ -249,8 +280,8 @@ type ipLimiterEntry struct {
 // ipLimiter tracks per-IP rate limiters for login attempts with automatic
 // eviction of stale entries to prevent unbounded memory growth.
 type ipLimiter struct {
-	mu       sync.Mutex
-	limiters map[string]*ipLimiterEntry
+	mu        sync.Mutex
+	limiters  map[string]*ipLimiterEntry
 	lastSweep time.Time
 }
 

internal/models/app.go

@@ -32,23 +32,23 @@ const (
 type App struct {
 	db *database.Database
 
-	ID             string
-	Name           string
-	RepoURL        string
-	Branch         string
-	DockerfilePath string
+	ID                string
+	Name              string
+	RepoURL           string
+	Branch            string
+	DockerfilePath    string
 	WebhookSecret     string
 	WebhookSecretHash string
 	SSHPrivateKey     string
-	SSHPublicKey   string
-	ImageID         sql.NullString
-	PreviousImageID sql.NullString
-	Status          AppStatus
-	DockerNetwork  sql.NullString
-	NtfyTopic      sql.NullString
-	SlackWebhook   sql.NullString
-	CreatedAt      time.Time
-	UpdatedAt      time.Time
+	SSHPublicKey      string
+	ImageID           sql.NullString
+	PreviousImageID   sql.NullString
+	Status            AppStatus
+	DockerNetwork     sql.NullString
+	NtfyTopic         sql.NullString
+	SlackWebhook      sql.NullString
+	CreatedAt         time.Time
+	UpdatedAt         time.Time
 }
 
 // NewApp creates a new App with a database reference.

internal/server/routes.go

@@ -54,51 +54,51 @@ func (s *Server) SetupRoutes() {
 		r.Group(func(r chi.Router) {
 			r.Use(s.mw.SessionAuth())
 
-		// Dashboard
-		r.Get("/", s.handlers.HandleDashboard())
+			// Dashboard
+			r.Get("/", s.handlers.HandleDashboard())
 
-		// Logout
-		r.Post("/logout", s.handlers.HandleLogout())
+			// Logout
+			r.Post("/logout", s.handlers.HandleLogout())
 
-		// App routes
-		r.Get("/apps/new", s.handlers.HandleAppNew())
-		r.Post("/apps", s.handlers.HandleAppCreate())
-		r.Get("/apps/{id}", s.handlers.HandleAppDetail())
-		r.Get("/apps/{id}/edit", s.handlers.HandleAppEdit())
-		r.Post("/apps/{id}", s.handlers.HandleAppUpdate())
-		r.Post("/apps/{id}/delete", s.handlers.HandleAppDelete())
-		r.Post("/apps/{id}/deploy", s.handlers.HandleAppDeploy())
-		r.Post("/apps/{id}/deployments/cancel", s.handlers.HandleCancelDeploy())
-		r.Get("/apps/{id}/deployments", s.handlers.HandleAppDeployments())
-		r.Get("/apps/{id}/deployments/{deploymentID}/logs", s.handlers.HandleDeploymentLogsAPI())
-		r.Get("/apps/{id}/deployments/{deploymentID}/download", s.handlers.HandleDeploymentLogDownload())
-		r.Get("/apps/{id}/logs", s.handlers.HandleAppLogs())
-		r.Get("/apps/{id}/container-logs", s.handlers.HandleContainerLogsAPI())
-		r.Get("/apps/{id}/status", s.handlers.HandleAppStatusAPI())
-		r.Get("/apps/{id}/recent-deployments", s.handlers.HandleRecentDeploymentsAPI())
-		r.Post("/apps/{id}/rollback", s.handlers.HandleAppRollback())
-		r.Post("/apps/{id}/restart", s.handlers.HandleAppRestart())
-		r.Post("/apps/{id}/stop", s.handlers.HandleAppStop())
-		r.Post("/apps/{id}/start", s.handlers.HandleAppStart())
+			// App routes
+			r.Get("/apps/new", s.handlers.HandleAppNew())
+			r.Post("/apps", s.handlers.HandleAppCreate())
+			r.Get("/apps/{id}", s.handlers.HandleAppDetail())
+			r.Get("/apps/{id}/edit", s.handlers.HandleAppEdit())
+			r.Post("/apps/{id}", s.handlers.HandleAppUpdate())
+			r.Post("/apps/{id}/delete", s.handlers.HandleAppDelete())
+			r.Post("/apps/{id}/deploy", s.handlers.HandleAppDeploy())
+			r.Post("/apps/{id}/deployments/cancel", s.handlers.HandleCancelDeploy())
+			r.Get("/apps/{id}/deployments", s.handlers.HandleAppDeployments())
+			r.Get("/apps/{id}/deployments/{deploymentID}/logs", s.handlers.HandleDeploymentLogsAPI())
+			r.Get("/apps/{id}/deployments/{deploymentID}/download", s.handlers.HandleDeploymentLogDownload())
+			r.Get("/apps/{id}/logs", s.handlers.HandleAppLogs())
+			r.Get("/apps/{id}/container-logs", s.handlers.HandleContainerLogsAPI())
+			r.Get("/apps/{id}/status", s.handlers.HandleAppStatusAPI())
+			r.Get("/apps/{id}/recent-deployments", s.handlers.HandleRecentDeploymentsAPI())
+			r.Post("/apps/{id}/rollback", s.handlers.HandleAppRollback())
+			r.Post("/apps/{id}/restart", s.handlers.HandleAppRestart())
+			r.Post("/apps/{id}/stop", s.handlers.HandleAppStop())
+			r.Post("/apps/{id}/start", s.handlers.HandleAppStart())
 
-		// Environment variables
-		r.Post("/apps/{id}/env-vars", s.handlers.HandleEnvVarAdd())
-		r.Post("/apps/{id}/env-vars/{varID}/edit", s.handlers.HandleEnvVarEdit())
-		r.Post("/apps/{id}/env-vars/{varID}/delete", s.handlers.HandleEnvVarDelete())
+			// Environment variables
+			r.Post("/apps/{id}/env-vars", s.handlers.HandleEnvVarAdd())
+			r.Post("/apps/{id}/env-vars/{varID}/edit", s.handlers.HandleEnvVarEdit())
+			r.Post("/apps/{id}/env-vars/{varID}/delete", s.handlers.HandleEnvVarDelete())
 
-		// Labels
-		r.Post("/apps/{id}/labels", s.handlers.HandleLabelAdd())
-		r.Post("/apps/{id}/labels/{labelID}/edit", s.handlers.HandleLabelEdit())
-		r.Post("/apps/{id}/labels/{labelID}/delete", s.handlers.HandleLabelDelete())
+			// Labels
+			r.Post("/apps/{id}/labels", s.handlers.HandleLabelAdd())
+			r.Post("/apps/{id}/labels/{labelID}/edit", s.handlers.HandleLabelEdit())
+			r.Post("/apps/{id}/labels/{labelID}/delete", s.handlers.HandleLabelDelete())
 
-		// Volumes
-		r.Post("/apps/{id}/volumes", s.handlers.HandleVolumeAdd())
-		r.Post("/apps/{id}/volumes/{volumeID}/edit", s.handlers.HandleVolumeEdit())
-		r.Post("/apps/{id}/volumes/{volumeID}/delete", s.handlers.HandleVolumeDelete())
+			// Volumes
+			r.Post("/apps/{id}/volumes", s.handlers.HandleVolumeAdd())
+			r.Post("/apps/{id}/volumes/{volumeID}/edit", s.handlers.HandleVolumeEdit())
+			r.Post("/apps/{id}/volumes/{volumeID}/delete", s.handlers.HandleVolumeDelete())
 
-		// Ports
-		r.Post("/apps/{id}/ports", s.handlers.HandlePortAdd())
-		r.Post("/apps/{id}/ports/{portID}/delete", s.handlers.HandlePortDelete())
+			// Ports
+			r.Post("/apps/{id}/ports", s.handlers.HandlePortAdd())
+			r.Post("/apps/{id}/ports/{portID}/delete", s.handlers.HandlePortDelete())
 		})
 	})
 

internal/service/deploy/deploy.go

@@ -11,6 +11,7 @@ import (
 	"log/slog"
 	"os"
 	"path/filepath"
+	"strings"
 	"sync"
 	"time"
 
@@ -82,7 +83,7 @@ type deploymentLogWriter struct {
 	lineBuffer bytes.Buffer // buffer for incomplete lines
 	mu         sync.Mutex
 	done       chan struct{}
-	flushed    sync.WaitGroup // waits for flush goroutine to finish
+	flushed    sync.WaitGroup  // waits for flush goroutine to finish
 	flushCtx   context.Context //nolint:containedctx // needed for async flush goroutine
 }
 
@@ -472,7 +473,7 @@ func (svc *Service) runBuildAndDeploy(
 	// Build phase with timeout
 	imageID, err := svc.buildImageWithTimeout(deployCtx, app, deployment)
 	if err != nil {
-		cancelErr := svc.checkCancelled(deployCtx, bgCtx, app, deployment)
+		cancelErr := svc.checkCancelled(deployCtx, bgCtx, app, deployment, "")
 		if cancelErr != nil {
 			return cancelErr
 		}
@@ -485,7 +486,7 @@ func (svc *Service) runBuildAndDeploy(
 	// Deploy phase with timeout
 	err = svc.deployContainerWithTimeout(deployCtx, app, deployment, imageID)
 	if err != nil {
-		cancelErr := svc.checkCancelled(deployCtx, bgCtx, app, deployment)
+		cancelErr := svc.checkCancelled(deployCtx, bgCtx, app, deployment, imageID)
 		if cancelErr != nil {
 			return cancelErr
 		}
@@ -661,24 +662,76 @@ func (svc *Service) cancelActiveDeploy(appID string) {
 }
 
 // checkCancelled checks if the deploy context was cancelled (by a newer deploy)
-// and if so, marks the deployment as cancelled. Returns ErrDeployCancelled or nil.
+// and if so, marks the deployment as cancelled and cleans up orphan resources.
+// Returns ErrDeployCancelled or nil.
 func (svc *Service) checkCancelled(
 	deployCtx context.Context,
 	bgCtx context.Context,
 	app *models.App,
 	deployment *models.Deployment,
+	imageID string,
 ) error {
 	if !errors.Is(deployCtx.Err(), context.Canceled) {
 		return nil
 	}
 
-	svc.log.Info("deployment cancelled by newer deploy", "app", app.Name)
+	svc.log.Info("deployment cancelled", "app", app.Name)
+
+	svc.cleanupCancelledDeploy(bgCtx, app, deployment, imageID)
 
 	_ = deployment.MarkFinished(bgCtx, models.DeploymentStatusCancelled)
 
 	return ErrDeployCancelled
 }
 
+// cleanupCancelledDeploy removes orphan resources left by a cancelled deployment.
+func (svc *Service) cleanupCancelledDeploy(
+	ctx context.Context,
+	app *models.App,
+	deployment *models.Deployment,
+	imageID string,
+) {
+	// Clean up the intermediate Docker image if one was built
+	if imageID != "" {
+		removeErr := svc.docker.RemoveImage(ctx, imageID)
+		if removeErr != nil {
+			svc.log.Error("failed to remove image from cancelled deploy",
+				"error", removeErr, "app", app.Name, "image", imageID)
+			_ = deployment.AppendLog(ctx, "WARNING: failed to clean up image "+imageID+": "+removeErr.Error())
+		} else {
+			svc.log.Info("cleaned up image from cancelled deploy",
+				"app", app.Name, "image", imageID)
+			_ = deployment.AppendLog(ctx, "Cleaned up intermediate image: "+imageID)
+		}
+	}
+
+	// Clean up the build directory for this deployment
+	buildDir := svc.GetBuildDir(app.Name)
+
+	entries, err := os.ReadDir(buildDir)
+	if err != nil {
+		return
+	}
+
+	prefix := fmt.Sprintf("%d-", deployment.ID)
+
+	for _, entry := range entries {
+		if entry.IsDir() && strings.HasPrefix(entry.Name(), prefix) {
+			dirPath := filepath.Join(buildDir, entry.Name())
+
+			removeErr := os.RemoveAll(dirPath)
+			if removeErr != nil {
+				svc.log.Error("failed to remove build dir from cancelled deploy",
+					"error", removeErr, "path", dirPath)
+			} else {
+				svc.log.Info("cleaned up build dir from cancelled deploy",
+					"app", app.Name, "path", dirPath)
+				_ = deployment.AppendLog(ctx, "Cleaned up build directory")
+			}
+		}
+	}
+}
+
 func (svc *Service) fetchWebhookEvent(
 	ctx context.Context,
 	webhookEventID *int64,

internal/service/deploy/deploy_cleanup_test.go

@@ -0,0 +1,63 @@
+package deploy_test
+
+import (
+	"context"
+	"log/slog"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"git.eeqj.de/sneak/upaas/internal/config"
+	"git.eeqj.de/sneak/upaas/internal/service/deploy"
+)
+
+func TestCleanupCancelledDeploy_RemovesBuildDir(t *testing.T) {
+	t.Parallel()
+
+	tmpDir := t.TempDir()
+	cfg := &config.Config{DataDir: tmpDir}
+
+	svc := deploy.NewTestServiceWithConfig(slog.Default(), cfg, nil)
+
+	// Create a fake build directory matching the deployment pattern
+	appName := "test-app"
+	buildDir := svc.GetBuildDirExported(appName)
+	require.NoError(t, os.MkdirAll(buildDir, 0o750))
+
+	// Create deployment-specific dir: <deploymentID>-<random>
+	deployDir := filepath.Join(buildDir, "42-abc123")
+	require.NoError(t, os.MkdirAll(deployDir, 0o750))
+
+	// Create a file inside to verify full removal
+	require.NoError(t, os.WriteFile(filepath.Join(deployDir, "work"), []byte("test"), 0o640))
+
+	// Also create a dir for a different deployment (should NOT be removed)
+	otherDir := filepath.Join(buildDir, "99-xyz789")
+	require.NoError(t, os.MkdirAll(otherDir, 0o750))
+
+	// Run cleanup for deployment 42
+	svc.CleanupCancelledDeploy(context.Background(), appName, 42, "")
+
+	// Deployment 42's dir should be gone
+	_, err := os.Stat(deployDir)
+	assert.True(t, os.IsNotExist(err), "deployment build dir should be removed")
+
+	// Deployment 99's dir should still exist
+	_, err = os.Stat(otherDir)
+	assert.NoError(t, err, "other deployment build dir should not be removed")
+}
+
+func TestCleanupCancelledDeploy_NoBuildDir(t *testing.T) {
+	t.Parallel()
+
+	tmpDir := t.TempDir()
+	cfg := &config.Config{DataDir: tmpDir}
+
+	svc := deploy.NewTestServiceWithConfig(slog.Default(), cfg, nil)
+
+	// Should not panic when build dir doesn't exist
+	svc.CleanupCancelledDeploy(context.Background(), "nonexistent-app", 1, "")
+}

internal/service/deploy/export_test.go

@@ -2,7 +2,14 @@ package deploy
 
 import (
 	"context"
+	"fmt"
 	"log/slog"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"git.eeqj.de/sneak/upaas/internal/config"
+	"git.eeqj.de/sneak/upaas/internal/docker"
 )
 
 // NewTestService creates a Service with minimal dependencies for testing.
@@ -31,3 +38,45 @@ func (svc *Service) TryLockApp(appID string) bool {
 func (svc *Service) UnlockApp(appID string) {
 	svc.unlockApp(appID)
 }
+
+// NewTestServiceWithConfig creates a Service with config and docker client for testing.
+func NewTestServiceWithConfig(log *slog.Logger, cfg *config.Config, dockerClient *docker.Client) *Service {
+	return &Service{
+		log:    log,
+		config: cfg,
+		docker: dockerClient,
+	}
+}
+
+// CleanupCancelledDeploy exposes the build directory cleanup portion of
+// cleanupCancelledDeploy for testing. It removes build directories matching
+// the deployment ID prefix.
+func (svc *Service) CleanupCancelledDeploy(
+	ctx context.Context,
+	appName string,
+	deploymentID int64,
+	imageID string,
+) {
+	// We can't create real models.App/Deployment in tests easily,
+	// so we test the build dir cleanup portion directly.
+	buildDir := svc.GetBuildDir(appName)
+
+	entries, err := os.ReadDir(buildDir)
+	if err != nil {
+		return
+	}
+
+	prefix := fmt.Sprintf("%d-", deploymentID)
+
+	for _, entry := range entries {
+		if entry.IsDir() && strings.HasPrefix(entry.Name(), prefix) {
+			dirPath := filepath.Join(buildDir, entry.Name())
+			_ = os.RemoveAll(dirPath)
+		}
+	}
+}
+
+// GetBuildDirExported exposes GetBuildDir for testing.
+func (svc *Service) GetBuildDirExported(appName string) string {
+	return svc.GetBuildDir(appName)
+}