fix: resolve lint issues for make check compliance

internal/config/config.go

@@ -51,7 +51,7 @@ type Config struct {
 	MaintenanceMode bool
 	MetricsUsername string
 	MetricsPassword string
-	SessionSecret   string
+	SessionSecret   string //nolint:gosec // not a hardcoded credential, loaded from env/file
 	CORSOrigins     string
 	params          *Params
 	log             *slog.Logger

internal/docker/client.go

@@ -480,6 +480,20 @@ func (c *Client) CloneRepo(
 	return c.performClone(ctx, cfg)
 }
 
+// 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) performBuild(
 	ctx context.Context,
 	opts BuildImageOptions,
@@ -740,20 +754,6 @@ 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

@@ -76,7 +76,7 @@ func deploymentToAPI(d *models.Deployment) apiDeploymentResponse {
 func (h *Handlers) HandleAPILoginPOST() http.HandlerFunc {
 	type loginRequest struct {
 		Username string `json:"username"`
-		Password string `json:"password"`
+		Password string `json:"password"` //nolint:gosec // request field, not a hardcoded credential
 	}
 
 	type loginResponse struct {
@@ -178,6 +178,27 @@ func (h *Handlers) HandleAPIGetApp() http.HandlerFunc {
 }
 
 // HandleAPICreateApp returns a handler that creates a new app.
+// validateCreateAppRequest checks all fields of a create-app request and returns
+// a user-facing error string or empty string if valid.
+func validateCreateAppRequest(name, repoURL string) string {
+	if name == "" || repoURL == "" {
+		return "name and repo_url are required"
+	}
+
+	nameErr := validateAppName(name)
+	if nameErr != nil {
+		return "invalid app name: " + nameErr.Error()
+	}
+
+	repoURLErr := ValidateRepoURL(repoURL)
+	if repoURLErr != nil {
+		return "invalid repository URL: " + repoURLErr.Error()
+	}
+
+	return ""
+}
+
+// HandleAPICreateApp returns a handler that creates a new app via the API.
 func (h *Handlers) HandleAPICreateApp() http.HandlerFunc {
 	type createRequest struct {
 		Name           string `json:"name"`
@@ -201,27 +222,9 @@ func (h *Handlers) HandleAPICreateApp() http.HandlerFunc {
 			return
 		}
 
-		if req.Name == "" || req.RepoURL == "" {
+		if validationErr := validateCreateAppRequest(req.Name, req.RepoURL); validationErr != "" {
 			h.respondJSON(writer, request,
-				map[string]string{"error": "name and repo_url are required"},
-				http.StatusBadRequest)
-
-			return
-		}
-
-		nameErr := validateAppName(req.Name)
-		if nameErr != nil {
-			h.respondJSON(writer, request,
-				map[string]string{"error": "invalid app name: " + nameErr.Error()},
-				http.StatusBadRequest)
-
-			return
-		}
-
-		repoURLErr := validateRepoURL(req.RepoURL)
-		if repoURLErr != nil {
-			h.respondJSON(writer, request,
-				map[string]string{"error": "invalid repository URL: " + repoURLErr.Error()},
+				map[string]string{"error": validationErr},
 				http.StatusBadRequest)
 
 			return

internal/handlers/app.go

@@ -77,7 +77,7 @@ func (h *Handlers) HandleAppCreate() http.HandlerFunc { //nolint:funlen // valid
 			return
 		}
 
-		repoURLErr := validateRepoURL(repoURL)
+		repoURLErr := ValidateRepoURL(repoURL)
 		if repoURLErr != nil {
 			data["Error"] = "Invalid repository URL: " + repoURLErr.Error()
 			h.renderTemplate(writer, tmpl, "app_new.html", data)
@@ -233,7 +233,7 @@ func (h *Handlers) HandleAppUpdate() http.HandlerFunc { //nolint:funlen // valid
 			return
 		}
 
-		repoURLErr := validateRepoURL(request.FormValue("repo_url"))
+		repoURLErr := ValidateRepoURL(request.FormValue("repo_url"))
 		if repoURLErr != nil {
 			data := h.addGlobals(map[string]any{
 				"App":   application,
@@ -518,7 +518,8 @@ func (h *Handlers) HandleAppLogs() http.HandlerFunc {
 			return
 		}
 
-		_, _ = writer.Write([]byte(logs))
+		//nolint:gosec // logs sanitized: ANSI escapes and control chars stripped
+		_, _ = writer.Write([]byte(SanitizeLogs(logs)))
 	}
 }
 
@@ -553,11 +554,11 @@ func (h *Handlers) HandleDeploymentLogsAPI() http.HandlerFunc {
 
 		logs := ""
 		if deployment.Logs.Valid {
-			logs = deployment.Logs.String
+			logs = SanitizeLogs(deployment.Logs.String)
 		}
 
 		response := map[string]any{
-			"logs":   logs,
+			"logs":   SanitizeLogs(logs),
 			"status": deployment.Status,
 		}
 
@@ -601,7 +602,7 @@ func (h *Handlers) HandleDeploymentLogDownload() http.HandlerFunc {
 		}
 
 		// Check if file exists
-		_, err := os.Stat(logPath)
+		_, err := os.Stat(logPath) //nolint:gosec // logPath is constructed by deploy service, not from user input
 		if os.IsNotExist(err) {
 			http.NotFound(writer, request)
 
@@ -680,7 +681,7 @@ func (h *Handlers) HandleContainerLogsAPI() http.HandlerFunc {
 		}
 
 		response := map[string]any{
-			"logs":   logs,
+			"logs":   SanitizeLogs(logs),
 			"status": status,
 		}
 

internal/handlers/repo_url_validation.go

@@ -20,8 +20,8 @@ var (
 // 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 {
+// 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
 	}
@@ -41,16 +41,19 @@ func validateRepoURL(repoURL string) error {
 		return errRepoURLScheme
 	}
 
-	// Parse as standard URL
+	return validateParsedURL(repoURL)
+}
+
+// validateParsedURL validates a standard URL format repository URL.
+func validateParsedURL(repoURL string) error {
 	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
+		// allowed
 	default:
 		return errRepoURLInvalid
 	}

internal/handlers/repo_url_validation_test.go

@@ -1,6 +1,10 @@
-package handlers
+package handlers_test
 
-import "testing"
+import (
+	"testing"
+
+	"git.eeqj.de/sneak/upaas/internal/handlers"
+)
 
 func TestValidateRepoURL(t *testing.T) {
 	t.Parallel()
@@ -43,13 +47,13 @@ func TestValidateRepoURL(t *testing.T) {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
 
-			err := validateRepoURL(tc.url)
+			err := handlers.ValidateRepoURL(tc.url)
 			if tc.wantErr && err == nil {
-				t.Errorf("validateRepoURL(%q) = nil, want error", tc.url)
+				t.Errorf("handlers.ValidateRepoURL(%q) = nil, want error", tc.url)
 			}
 
 			if !tc.wantErr && err != nil {
-				t.Errorf("validateRepoURL(%q) = %v, want nil", tc.url, err)
+				t.Errorf("handlers.ValidateRepoURL(%q) = %v, want nil", tc.url, err)
 			}
 		})
 	}

internal/handlers/sanitize.go

@@ -0,0 +1,30 @@
+package handlers
+
+import (
+	"regexp"
+	"strings"
+)
+
+// ansiEscapePattern matches ANSI escape sequences (CSI, OSC, and single-character escapes).
+var ansiEscapePattern = regexp.MustCompile(`(\x1b\[[0-9;]*[a-zA-Z]|\x1b\][^\x07]*\x07|\x1b[^[\]])`)
+
+// SanitizeLogs strips ANSI escape sequences and non-printable control characters
+// from container log output. Newlines (\n), carriage returns (\r), and tabs (\t)
+// are preserved. This ensures that attacker-controlled container output cannot
+// inject terminal escape sequences or other dangerous control characters.
+func SanitizeLogs(input string) string {
+	// Strip ANSI escape sequences
+	result := ansiEscapePattern.ReplaceAllString(input, "")
+
+	// Strip remaining non-printable characters (keep \n, \r, \t)
+	var b strings.Builder
+	b.Grow(len(result))
+
+	for _, r := range result {
+		if r == '\n' || r == '\r' || r == '\t' || r >= ' ' {
+			b.WriteRune(r)
+		}
+	}
+
+	return b.String()
+}

internal/handlers/sanitize_test.go

@@ -0,0 +1,84 @@
+package handlers_test
+
+import (
+	"testing"
+
+	"git.eeqj.de/sneak/upaas/internal/handlers"
+)
+
+func TestSanitizeLogs(t *testing.T) { //nolint:funlen // table-driven tests
+	t.Parallel()
+
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{
+			name:     "plain text unchanged",
+			input:    "hello world\n",
+			expected: "hello world\n",
+		},
+		{
+			name:     "strips ANSI color codes",
+			input:    "\x1b[31mERROR\x1b[0m: something failed\n",
+			expected: "ERROR: something failed\n",
+		},
+		{
+			name:     "strips OSC sequences",
+			input:    "\x1b]0;window title\x07normal text\n",
+			expected: "normal text\n",
+		},
+		{
+			name:     "strips null bytes",
+			input:    "hello\x00world\n",
+			expected: "helloworld\n",
+		},
+		{
+			name:     "strips bell characters",
+			input:    "alert\x07here\n",
+			expected: "alerthere\n",
+		},
+		{
+			name:     "preserves tabs",
+			input:    "field1\tfield2\tfield3\n",
+			expected: "field1\tfield2\tfield3\n",
+		},
+		{
+			name:     "preserves carriage returns",
+			input:    "line1\r\nline2\r\n",
+			expected: "line1\r\nline2\r\n",
+		},
+		{
+			name:     "strips mixed escape sequences",
+			input:    "\x1b[32m2024-01-01\x1b[0m \x1b[1mINFO\x1b[0m starting\x00\n",
+			expected: "2024-01-01 INFO starting\n",
+		},
+		{
+			name:     "empty string",
+			input:    "",
+			expected: "",
+		},
+		{
+			name:     "only control characters",
+			input:    "\x00\x01\x02\x03",
+			expected: "",
+		},
+		{
+			name:     "cursor movement sequences stripped",
+			input:    "\x1b[2J\x1b[H\x1b[3Atext\n",
+			expected: "text\n",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			got := handlers.SanitizeLogs(tt.input)
+			if got != tt.expected {
+				t.Errorf("SanitizeLogs(%q) = %q, want %q", tt.input, got, tt.expected)
+			}
+		})
+	}
+}

internal/service/deploy/deploy.go

@@ -726,6 +726,7 @@ func (svc *Service) cleanupCancelledDeploy(
 			} else {
 				svc.log.Info("cleaned up build dir from cancelled deploy",
 					"app", app.Name, "path", dirPath)
+
 				_ = deployment.AppendLog(ctx, "Cleaned up build directory")
 			}
 		}

internal/service/deploy/deploy_cleanup_test.go

@@ -32,7 +32,7 @@ func TestCleanupCancelledDeploy_RemovesBuildDir(t *testing.T) {
 	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))
+	require.NoError(t, os.WriteFile(filepath.Join(deployDir, "work"), []byte("test"), 0o600))
 
 	// Also create a dir for a different deployment (should NOT be removed)
 	otherDir := filepath.Join(buildDir, "99-xyz789")

internal/service/deploy/export_test.go

@@ -52,10 +52,10 @@ func NewTestServiceWithConfig(log *slog.Logger, cfg *config.Config, dockerClient
 // cleanupCancelledDeploy for testing. It removes build directories matching
 // the deployment ID prefix.
 func (svc *Service) CleanupCancelledDeploy(
-	ctx context.Context,
+	_ context.Context,
 	appName string,
 	deploymentID int64,
-	imageID string,
+	_ string,
 ) {
 	// We can't create real models.App/Deployment in tests easily,
 	// so we test the build dir cleanup portion directly.

internal/service/notify/notify.go

@@ -260,7 +260,7 @@ func (svc *Service) sendNtfy(
 	request.Header.Set("Title", title)
 	request.Header.Set("Priority", svc.ntfyPriority(priority))
 
-	resp, err := svc.client.Do(request)
+	resp, err := svc.client.Do(request) //nolint:gosec // URL constructed from trusted config, not user input
 	if err != nil {
 		return fmt.Errorf("failed to send ntfy request: %w", err)
 	}
@@ -352,7 +352,7 @@ func (svc *Service) sendSlack(
 
 	request.Header.Set("Content-Type", "application/json")
 
-	resp, err := svc.client.Do(request)
+	resp, err := svc.client.Do(request) //nolint:gosec // URL from trusted webhook config
 	if err != nil {
 		return fmt.Errorf("failed to send slack request: %w", err)
 	}

internal/ssh/keygen.go

@@ -12,7 +12,7 @@ import (
 
 // KeyPair contains an SSH key pair.
 type KeyPair struct {
-	PrivateKey string
+	PrivateKey string //nolint:gosec // field name describes SSH key material, not a hardcoded secret
 	PublicKey  string
 }