Enforce the body size limit before CSRF parses the form (closes #90)

chi runs Use middleware in registration order, and every form route
group registered CSRF() before MaxBodySize(). gorilla/csrf calls
r.PostFormValue, so the form was parsed under net/http's 10 MB default
and the intended 1 MB cap never applied to form fields. The
/user/{username} group, which carries POST /password, had no
MaxBodySize registration at all.

- Register MaxBodySize ahead of CSRF in /pages, /sources, and
  /source/{sourceID}, and add it to /user/{username}.
- Reject a declared-oversize body up front with 413. Reordering alone
  cannot produce one: http.MaxBytesReader surfaces its error on Read,
  so the form parse fails and gorilla/csrf answers 403 "no token" for
  what is really an oversized body. MaxBytesReader is still installed
  afterwards so chunked or length-lying clients stay hard-capped.
- Drop the handler-local MaxBytesReader calls in auth.go, profile.go,
  and source_management.go now that the middleware is the single
  enforcement point. maxBodyShift stays; webhook.go still uses it.

The /webhook/{uuid} receiver is untouched: it bounds itself with
io.LimitReader in readWebhookBody and is neither CSRF-protected nor
form-parsed.

Tests cover the middleware in isolation (declared oversize is rejected
without reaching a sentinel handler; at-limit and under-limit bodies
pass through intact; GET is unaffected; an undeclared oversize body is
truncated at the cap) and the real router built by SetupRoutes, so the
registration order itself is guarded: an oversized POST to
/pages/login returns 413 with no gorilla/csrf cookie issued, an
oversized POST /password with a valid session and CSRF token returns
413 and leaves the stored hash unchanged, and under-limit requests
still complete through the normal CSRF path.

README.md

@@ -89,27 +89,10 @@ TTY detection, and security headers are always applied.
 | `PORT`                  | HTTP listen port                    | `8080`   |
 | `DATA_DIR`              | Directory for all SQLite databases  | `/var/lib/webhooker` |
 | `DEBUG`                 | Enable debug logging                | `false`  |
-| `MAINTENANCE_MODE`      | Serve the maintenance page          | `false`  |
 | `METRICS_USERNAME`      | Basic auth username for `/metrics`  | `""`     |
 | `METRICS_PASSWORD`      | Basic auth password for `/metrics`  | `""`     |
 | `SENTRY_DSN`            | Sentry error reporting DSN          | `""`     |
 
-#### Invalid values abort startup
-
-The defaults above apply **only** to variables that are unset (or set
-to an empty string). A variable that is set but cannot be parsed is a
-fatal configuration error: webhooker logs the offending variable and
-its value and refuses to start, rather than silently running with a
-substituted default. `PORT=eighty`, `DEBUG=ture`, and
-`RETENTION_SWEEP_INTERVAL=1 hour` all abort startup. `PORT` must
-additionally be a number in the range 1–65535.
-
-Boolean variables (`DEBUG`, `MAINTENANCE_MODE`) accept exactly the
-spellings Go's `strconv.ParseBool` accepts — `1`, `t`, `T`, `TRUE`,
-`true`, `True`, `0`, `f`, `F`, `FALSE`, `false`, `False` — and nothing
-else. `yes`, `on`, and `off` are rejected rather than quietly treated
-as false.
-
 On first startup, webhooker automatically generates a cryptographically
 secure session encryption key and stores it in the database. This key
 persists across restarts — no manual key management is needed.
@@ -884,9 +867,17 @@ Applied to all routes in this order:
 8. **Sentry** — Error reporting to Sentry (if `SENTRY_DSN` is set;
    configured with `Repanic: true` so panics still reach Recoverer)
 
-Additionally, form endpoints (`/pages`, `/sources`, `/source/*`) apply a
-**MaxBodySize** middleware that limits POST/PUT/PATCH request bodies to
-1 MB using `http.MaxBytesReader`, preventing oversized form submissions.
+Additionally, form endpoints (`/pages`, `/user/*`, `/sources`,
+`/source/*`) apply a **MaxBodySize** middleware that limits
+POST/PUT/PATCH request bodies to 1 MB. It is registered ahead of the
+CSRF middleware in every one of those route groups, because
+gorilla/csrf parses the form; if the cap were installed after it, form
+parsing would run under net/http's 10 MB default and the 1 MB limit
+would never apply. A request that declares a `Content-Length` over the
+limit is answered with `413 Request Entity Too Large` before any other
+middleware or handler runs; a chunked request, or one that lies about
+its length, is hard-capped by `http.MaxBytesReader` and fails
+downstream at form-parse time.
 
 ### Authentication
 
@@ -908,7 +899,8 @@ Additionally, form endpoints (`/pages`, `/sources`, `/source/*`) apply a
 - Production security headers on all responses: HSTS, X-Content-Type-Options
   (`nosniff`), X-Frame-Options (`DENY`), Content-Security-Policy, Referrer-Policy,
   and Permissions-Policy
-- Request body size limits (1 MB) on all form POST endpoints
+- Request body size limits (1 MB) on all form POST endpoints, enforced
+  by middleware that runs before CSRF parses the form
 - **CSRF protection** via [gorilla/csrf](https://github.com/gorilla/csrf)
   on all state-changing forms (cookie-based double-submit tokens with
   HMAC authentication). Applied to `/pages`, `/sources`, `/source`, and

TODO.md

@@ -10,28 +10,31 @@
 
 # Status
 
-pre-1.0. No git tags exist. main (4f5ecb1) is a working webhook proxy
+pre-1.0. No git tags exist. main (afe88c6) is a working webhook proxy
 with auth, CSRF/SSRF protections, login rate limiting, Slack target,
-policy compliance (#6), pinned lint tooling (#55), a per-webhook event
-retention reaper (#63), and fail-loud configuration parsing (#80). Note:
-TODO.md was deliberately deleted from this repo in f9a9569 (2026-03-01,
-#6); its content was folded into the README TODO section, which this
-draft reconstructs as of 2026-07-06.
+policy compliance (#6), and pinned lint tooling (#55). Note: TODO.md was
+deliberately deleted from this repo in f9a9569 (2026-03-01, #6); its
+content was folded into the README TODO section, which this draft
+reconstructs as of 2026-07-06.
 
 # Next Step
 
-Manual event redelivery from the web UI (replay is a core promised
-capability in the README rationale).
+Implement automatic event retention cleanup based on retention_days: a
+periodic maintenance job that deletes Events, Deliveries, and
+DeliveryResults older than the parent webhook's retention_days from each
+per-webhook event database. The field exists on the Webhook model and
+the README promises the behavior, but nothing enforces it, so event
+databases currently grow without bound.
 
 # Completed Steps
 
-- 2026-08-09 Configuration parsing fails loudly on set-but-unparseable
-  environment values: `envInt` removed in favour of `envPositiveInt`
-  plus a `PORT` range check, `envBool` now parses with
-  `strconv.ParseBool`, and defaults apply only to unset variables (#80)
-- 2026-08-07 Automatic event retention cleanup based on
-  `retention_days`, deleting expired events, deliveries, and delivery
-  results from each per-webhook event database (#63)
+- 2026-08-09 Enforce the request body size limit before the CSRF
+  middleware parses the form (#90): `MaxBodySize` is now registered
+  ahead of `CSRF()` in every form route group, the `/user/{username}`
+  group gained the cap it never had (which is where `POST /password`
+  lives), the middleware rejects a declared-oversize body with a real
+  413 up front, and the redundant handler-local
+  `http.MaxBytesReader` calls were removed
 - 2026-08-07 Update golangci-lint to v2.12.2 (Docker image digest in
   `Dockerfile`, release-archive sha256 pins in `script/bootstrap`),
   adopt the canonical `.golangci.yml` (v2 `linters.settings` layout so
@@ -60,6 +63,8 @@ capability in the README rationale).
 
 # Future Steps
 
+- Manual event redelivery from the web UI (replay is a core promised
+  capability in the README rationale)
 - Delivery status and retry management UI
 - Per-webhook rate limiting in the receiver handler (per-webhook config
   plus handler enforcement; global limits must not apply to receiver

internal/config/config.go

@@ -7,6 +7,7 @@ import (
 	"log/slog"
 	"os"
 	"strconv"
+	"strings"
 	"time"
 
 	"go.uber.org/fx"
@@ -30,24 +31,12 @@ const (
 	// defaultRetentionSweepInterval is how often the retention
 	// reaper deletes events older than each webhook's RetentionDays.
 	defaultRetentionSweepInterval = time.Hour
-
-	// maxPort is the highest valid TCP port number. The lower
-	// bound (at least 1) is enforced by envPositiveInt.
-	maxPort = 65535
 )
 
 // ErrInvalidEnvironment is returned when WEBHOOKER_ENVIRONMENT
 // contains an unrecognised value.
 var ErrInvalidEnvironment = errors.New("invalid environment")
 
-// ErrNonPositiveValue is returned when an environment variable that
-// requires a positive integer is set to zero or a negative number.
-var ErrNonPositiveValue = errors.New("value must be positive")
-
-// ErrInvalidPort is returned when an environment variable holding a
-// TCP port number is set above the valid port range.
-var ErrInvalidPort = errors.New("invalid port")
-
 //nolint:revive // ConfigParams is a standard fx naming convention.
 type ConfigParams struct {
 	fx.In
@@ -92,81 +81,27 @@ func envString(key string) string {
 }
 
 // envBool returns the value of the named environment variable
-// parsed as a boolean. Returns defaultValue if not set. If the
-// variable is set but cannot be parsed, it returns a wrapped error
-// naming the key and the bad value, so startup fails loudly rather
-// than silently falling back to the default.
-//
-// Parsing is strconv.ParseBool, which accepts 1, t, T, TRUE, true,
-// True, 0, f, F, FALSE, false and False. Anything else — "yes",
-// "on", or a typo like "ture" — is an error rather than a silent
-// false.
-func envBool(key string, defaultValue bool) (bool, error) {
-	v := os.Getenv(key)
-	if v == "" {
-		return defaultValue, nil
+// parsed as a boolean. Returns defaultValue if not set.
+func envBool(key string, defaultValue bool) bool {
+	if v := os.Getenv(key); v != "" {
+		return strings.EqualFold(v, "true") || v == "1"
 	}
 
-	b, err := strconv.ParseBool(v)
-	if err != nil {
-		return false, fmt.Errorf(
-			"invalid boolean for %s: %q: %w", key, v, err,
-		)
-	}
-
-	return b, nil
-}
-
-// envPositiveInt returns the value of the named environment variable
-// parsed as a positive integer. Returns defaultValue if not set. If
-// the variable is set but cannot be parsed, or parses to less than
-// one, it returns a wrapped error naming the key and the bad value,
-// so startup fails loudly rather than silently falling back to the
-// default.
-func envPositiveInt(
-	key string,
-	defaultValue int,
-) (int, error) {
-	v := os.Getenv(key)
-	if v == "" {
-		return defaultValue, nil
+	return defaultValue
 }
 
+// envInt returns the value of the named environment variable
+// parsed as an integer. Returns defaultValue if not set or
+// unparseable.
+func envInt(key string, defaultValue int) int {
+	if v := os.Getenv(key); v != "" {
 		i, err := strconv.Atoi(v)
-	if err != nil {
-		return 0, fmt.Errorf(
-			"invalid integer for %s: %q: %w", key, v, err,
-		)
+		if err == nil {
+			return i
+		}
 	}
 
-	if i < 1 {
-		return 0, fmt.Errorf(
-			"%w: %s must be at least 1, got %q",
-			ErrNonPositiveValue, key, v,
-		)
-	}
-
-	return i, nil
-}
-
-// envPort returns the value of the named environment variable parsed
-// as a TCP port number. Returns defaultValue if not set. A set value
-// that is unparseable, below 1, or above maxPort is a hard error
-// naming the key and the bad value.
-func envPort(key string, defaultValue int) (int, error) {
-	port, err := envPositiveInt(key, defaultValue)
-	if err != nil {
-		return 0, err
-	}
-
-	if port > maxPort {
-		return 0, fmt.Errorf(
-			"%w: %s must be at most %d, got %d",
-			ErrInvalidPort, key, maxPort, port,
-		)
-	}
-
-	return port, nil
+	return defaultValue
 }
 
 // envDuration returns the value of the named environment variable
@@ -193,52 +128,32 @@ func envDuration(
 	return d, nil
 }
 
-// resolveEnvironment reads WEBHOOKER_ENVIRONMENT, defaulting to
-// dev, and rejects unrecognised values.
-func resolveEnvironment() (string, error) {
+// New creates a Config by reading environment variables.
+//
+//nolint:revive // lc parameter is required by fx even if unused.
+func New(lc fx.Lifecycle, params ConfigParams) (*Config, error) {
+	log := params.Logger.Get()
+
+	// Determine environment from WEBHOOKER_ENVIRONMENT env var,
+	// default to dev
 	environment := os.Getenv("WEBHOOKER_ENVIRONMENT")
 	if environment == "" {
 		environment = EnvironmentDev
 	}
 
+	// Validate environment
 	if environment != EnvironmentDev &&
 		environment != EnvironmentProd {
-		return "", fmt.Errorf(
+		return nil, fmt.Errorf(
 			"%w: WEBHOOKER_ENVIRONMENT must be '%s' or '%s', got '%s'",
 			ErrInvalidEnvironment,
 			EnvironmentDev, EnvironmentProd, environment,
 		)
 	}
 
-	return environment, nil
-}
-
-// loadFromEnv builds a Config from the environment. Every value that
-// needs parsing fails loudly when it is set but unparseable: the
-// documented defaults apply only to variables that are unset (or
-// empty), never as a substitute for a value the operator actually
-// provided.
-func loadFromEnv() (*Config, error) {
-	environment, err := resolveEnvironment()
-	if err != nil {
-		return nil, err
-	}
-
-	port, err := envPort("PORT", defaultPort)
-	if err != nil {
-		return nil, err
-	}
-
-	debug, err := envBool("DEBUG", false)
-	if err != nil {
-		return nil, err
-	}
-
-	maintenanceMode, err := envBool("MAINTENANCE_MODE", false)
-	if err != nil {
-		return nil, err
-	}
-
+	// Parse the retention sweep interval; a set-but-unparseable value
+	// is a hard error so fx aborts startup rather than silently using
+	// the default.
 	retentionSweepInterval, err := envDuration(
 		"RETENTION_SWEEP_INTERVAL",
 		defaultRetentionSweepInterval,
@@ -247,36 +162,21 @@ func loadFromEnv() (*Config, error) {
 		return nil, err
 	}
 
-	return &Config{
+	// Load configuration values from environment variables
+	s := &Config{
 		DataDir:                envString("DATA_DIR"),
-		Debug:                  debug,
-		MaintenanceMode:        maintenanceMode,
+		Debug:                  envBool("DEBUG", false),
+		MaintenanceMode:        envBool("MAINTENANCE_MODE", false),
 		Environment:            environment,
 		MetricsUsername:        envString("METRICS_USERNAME"),
 		MetricsPassword:        envString("METRICS_PASSWORD"),
-		Port:                   port,
+		Port:                   envInt("PORT", defaultPort),
 		SentryDSN:              envString("SENTRY_DSN"),
 		RetentionSweepInterval: retentionSweepInterval,
-	}, nil
+		log:                    log,
+		params:                 &params,
 	}
 
-// New creates a Config by reading environment variables.
-//
-//nolint:revive // lc parameter is required by fx even if unused.
-func New(lc fx.Lifecycle, params ConfigParams) (*Config, error) {
-	log := params.Logger.Get()
-
-	// A set-but-unparseable value anywhere in the environment is a
-	// hard error, so fx aborts startup rather than running with a
-	// silently substituted default.
-	s, err := loadFromEnv()
-	if err != nil {
-		return nil, err
-	}
-
-	s.log = log
-	s.params = &params
-
 	// Set default DataDir. All SQLite databases (main application
 	// DB and per-webhook event DBs) live here. The same default is
 	// used regardless of environment; override with DATA_DIR if

internal/config/env_test.go

@@ -1,409 +0,0 @@
-package config_test
-
-import (
-	"os"
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-	"go.uber.org/fx"
-	"sneak.berlin/go/webhooker/internal/config"
-	"sneak.berlin/go/webhooker/internal/globals"
-	"sneak.berlin/go/webhooker/internal/logger"
-)
-
-// testEnvKey is a throwaway variable name used only by the helper
-// tables below, so they cannot disturb real configuration.
-const testEnvKey = "WEBHOOKER_TEST_VALUE"
-
-// Real configuration variables exercised by the config.New tests.
-const (
-	envKeyPort            = "PORT"
-	envKeyDebug           = "DEBUG"
-	envKeyMaintenanceMode = "MAINTENANCE_MODE"
-)
-
-// envBoolCase is one row of the envBool table.
-type envBoolCase struct {
-	name         string
-	set          bool
-	value        string
-	defaultValue bool
-	expectError  bool
-	expected     bool
-}
-
-// envBoolCases is the envBool table, kept out of the test body so
-// the test itself stays readable.
-func envBoolCases() []envBoolCase {
-	return []envBoolCase{
-		{
-			name:         "unset uses default false",
-			defaultValue: false,
-			expected:     false,
-		},
-		{
-			name:         "unset uses default true",
-			defaultValue: true,
-			expected:     true,
-		},
-		{
-			name:         "empty uses default true",
-			set:          true,
-			value:        "",
-			defaultValue: true,
-			expected:     true,
-		},
-		{
-			name:     "true is parsed",
-			set:      true,
-			value:    "true",
-			expected: true,
-		},
-		{
-			name:     "one is parsed",
-			set:      true,
-			value:    "1",
-			expected: true,
-		},
-		{
-			name:         "False is parsed",
-			set:          true,
-			value:        "False",
-			defaultValue: true,
-			expected:     false,
-		},
-		{
-			name:         "zero is parsed",
-			set:          true,
-			value:        "0",
-			defaultValue: true,
-			expected:     false,
-		},
-		{
-			name:        "yes is rejected",
-			set:         true,
-			value:       "yes",
-			expectError: true,
-		},
-		{
-			name:        "on is rejected",
-			set:         true,
-			value:       "on",
-			expectError: true,
-		},
-		{
-			name:        "typo is rejected",
-			set:         true,
-			value:       "ture",
-			expectError: true,
-		},
-	}
-}
-
-func TestEnvBool(t *testing.T) {
-	for _, tt := range envBoolCases() {
-		t.Run(tt.name, func(t *testing.T) {
-			// Cannot use t.Parallel() here because t.Setenv
-			// is incompatible with parallel subtests.
-			if tt.set {
-				t.Setenv(testEnvKey, tt.value)
-			} else {
-				require.NoError(t, os.Unsetenv(testEnvKey))
-			}
-
-			got, err := config.EnvBoolForTest(
-				testEnvKey, tt.defaultValue,
-			)
-
-			if tt.expectError {
-				require.Error(t, err)
-				assert.Contains(t, err.Error(), testEnvKey)
-				assert.Contains(t, err.Error(), tt.value)
-
-				return
-			}
-
-			require.NoError(t, err)
-			assert.Equal(t, tt.expected, got)
-		})
-	}
-}
-
-func TestEnvPositiveInt(t *testing.T) {
-	const defaultValue = 7
-
-	tests := []struct {
-		name        string
-		set         bool
-		value       string
-		expectError bool
-		errIs       error
-		expected    int
-	}{
-		{
-			name:     "unset returns the default integer",
-			expected: defaultValue,
-		},
-		{
-			name:     "empty returns the default integer",
-			set:      true,
-			value:    "",
-			expected: defaultValue,
-		},
-		{
-			name:     "positive value is parsed",
-			set:      true,
-			value:    "42",
-			expected: 42,
-		},
-		{
-			name:        "unparseable value is rejected",
-			set:         true,
-			value:       "not-a-number",
-			expectError: true,
-		},
-		{
-			name:        "zero is rejected",
-			set:         true,
-			value:       "0",
-			expectError: true,
-			errIs:       config.ErrNonPositiveValue,
-		},
-		{
-			name:        "negative is rejected",
-			set:         true,
-			value:       "-5",
-			expectError: true,
-			errIs:       config.ErrNonPositiveValue,
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			// Cannot use t.Parallel() here because t.Setenv
-			// is incompatible with parallel subtests.
-			if tt.set {
-				t.Setenv(testEnvKey, tt.value)
-			} else {
-				require.NoError(t, os.Unsetenv(testEnvKey))
-			}
-
-			got, err := config.EnvPositiveIntForTest(
-				testEnvKey, defaultValue,
-			)
-
-			if tt.expectError {
-				require.Error(t, err)
-				assert.Contains(t, err.Error(), testEnvKey)
-				assert.Contains(t, err.Error(), tt.value)
-
-				if tt.errIs != nil {
-					require.ErrorIs(t, err, tt.errIs)
-				}
-
-				return
-			}
-
-			require.NoError(t, err)
-			assert.Equal(t, tt.expected, got)
-		})
-	}
-}
-
-func TestEnvPort(t *testing.T) {
-	const defaultValue = 8080
-
-	tests := []struct {
-		name        string
-		set         bool
-		value       string
-		expectError bool
-		errIs       error
-		expected    int
-	}{
-		{
-			name:     "unset returns the default port",
-			expected: defaultValue,
-		},
-		{
-			name:     "valid port is parsed",
-			set:      true,
-			value:    "9000",
-			expected: 9000,
-		},
-		{
-			name:     "highest port is accepted",
-			set:      true,
-			value:    "65535",
-			expected: 65535,
-		},
-		{
-			name:        "unparseable value is rejected",
-			set:         true,
-			value:       "not-a-port",
-			expectError: true,
-		},
-		{
-			name:        "zero is rejected",
-			set:         true,
-			value:       "0",
-			expectError: true,
-			errIs:       config.ErrNonPositiveValue,
-		},
-		{
-			name:        "above the port range is rejected",
-			set:         true,
-			value:       "65536",
-			expectError: true,
-			errIs:       config.ErrInvalidPort,
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			// Cannot use t.Parallel() here because t.Setenv
-			// is incompatible with parallel subtests.
-			if tt.set {
-				t.Setenv(testEnvKey, tt.value)
-			} else {
-				require.NoError(t, os.Unsetenv(testEnvKey))
-			}
-
-			got, err := config.EnvPortForTest(
-				testEnvKey, defaultValue,
-			)
-
-			if tt.expectError {
-				require.Error(t, err)
-				assert.Contains(t, err.Error(), testEnvKey)
-
-				if tt.errIs != nil {
-					require.ErrorIs(t, err, tt.errIs)
-				}
-
-				return
-			}
-
-			require.NoError(t, err)
-			assert.Equal(t, tt.expected, got)
-		})
-	}
-}
-
-// buildConfig constructs a Config through fx exactly as the
-// application does, returning the config and any construction error.
-func buildConfig(t *testing.T) (*config.Config, error) {
-	t.Helper()
-
-	var cfg *config.Config
-
-	app := fx.New(
-		fx.NopLogger,
-		fx.Provide(
-			globals.New,
-			logger.New,
-			config.New,
-		),
-		fx.Populate(&cfg),
-	)
-
-	return cfg, app.Err()
-}
-
-func TestNewRejectsBadEnvValues(t *testing.T) {
-	tests := []struct {
-		name        string
-		key         string
-		value       string
-		expectError bool
-		check       func(t *testing.T, cfg *config.Config)
-	}{
-		{
-			name:  "valid PORT is used",
-			key:   envKeyPort,
-			value: "9001",
-			check: func(t *testing.T, cfg *config.Config) {
-				t.Helper()
-				assert.Equal(t, 9001, cfg.Port)
-			},
-		},
-		{
-			name:        "unparseable PORT aborts startup",
-			key:         envKeyPort,
-			value:       "eighty-eighty",
-			expectError: true,
-		},
-		{
-			name:        "out-of-range PORT aborts startup",
-			key:         envKeyPort,
-			value:       "70000",
-			expectError: true,
-		},
-		{
-			name:  "valid DEBUG is used",
-			key:   envKeyDebug,
-			value: "true",
-			check: func(t *testing.T, cfg *config.Config) {
-				t.Helper()
-				assert.True(t, cfg.Debug)
-			},
-		},
-		{
-			name:        "unparseable DEBUG aborts startup",
-			key:         envKeyDebug,
-			value:       "ture",
-			expectError: true,
-		},
-		{
-			name:        "unparseable MAINTENANCE_MODE aborts startup",
-			key:         envKeyMaintenanceMode,
-			value:       "sometimes",
-			expectError: true,
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			// Cannot use t.Parallel() here because t.Setenv
-			// is incompatible with parallel subtests.
-			t.Setenv("WEBHOOKER_ENVIRONMENT", "dev")
-			t.Setenv(tt.key, tt.value)
-
-			cfg, err := buildConfig(t)
-
-			if tt.expectError {
-				require.Error(t, err)
-				assert.Contains(t, err.Error(), tt.key)
-				assert.Contains(t, err.Error(), tt.value)
-
-				return
-			}
-
-			require.NoError(t, err)
-			require.NotNil(t, cfg)
-			tt.check(t, cfg)
-		})
-	}
-}
-
-// TestNewUsesDefaultsWhenUnset proves the fail-loud behaviour did not
-// break the legitimate unset case: absent variables still get their
-// documented defaults.
-func TestNewUsesDefaultsWhenUnset(t *testing.T) {
-	t.Setenv("WEBHOOKER_ENVIRONMENT", "dev")
-
-	for _, key := range []string{
-		envKeyPort, envKeyDebug, envKeyMaintenanceMode,
-	} {
-		require.NoError(t, os.Unsetenv(key))
-	}
-
-	cfg, err := buildConfig(t)
-	require.NoError(t, err)
-	require.NotNil(t, cfg)
-
-	assert.Equal(t, 8080, cfg.Port)
-	assert.False(t, cfg.Debug)
-	assert.False(t, cfg.MaintenanceMode)
-}

internal/config/export_test.go

@@ -1,20 +0,0 @@
-package config
-
-// This file exposes the unexported environment parsing helpers to
-// the external config_test package so each helper can be covered by
-// its own table-driven test without weakening the package API.
-
-// EnvBoolForTest exposes envBool.
-func EnvBoolForTest(key string, defaultValue bool) (bool, error) {
-	return envBool(key, defaultValue)
-}
-
-// EnvPositiveIntForTest exposes envPositiveInt.
-func EnvPositiveIntForTest(key string, defaultValue int) (int, error) {
-	return envPositiveInt(key, defaultValue)
-}
-
-// EnvPortForTest exposes envPort.
-func EnvPortForTest(key string, defaultValue int) (int, error) {
-	return envPort(key, defaultValue)
-}

internal/handlers/auth.go

@@ -29,10 +29,8 @@ func (h *Handlers) HandleLoginPage() http.HandlerFunc {
 // HandleLoginSubmit handles the login form submission (POST)
 func (h *Handlers) HandleLoginSubmit() http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
-		// Limit request body to prevent memory exhaustion
-		r.Body = http.MaxBytesReader(w, r.Body, 1<<maxBodyShift)
-
-		// Parse form data
+		// The body size cap is enforced by the MaxBodySize
+		// middleware, which runs before CSRF parses the form.
 		err := r.ParseForm()
 		if err != nil {
 			h.log.Error("failed to parse form", "error", err)

internal/handlers/profile.go

@@ -31,9 +31,8 @@ func (h *Handlers) HandlePasswordChange() http.HandlerFunc {
 			return
 		}
 
-		// Limit request body to prevent memory exhaustion.
-		r.Body = http.MaxBytesReader(w, r.Body, 1<<maxBodyShift)
-
+		// The body size cap is enforced by the MaxBodySize
+		// middleware, which runs before CSRF parses the form.
 		err := r.ParseForm()
 		if err != nil {
 			h.log.Error("failed to parse form", "error", err)

internal/handlers/source_management.go

@@ -127,10 +127,8 @@ func (h *Handlers) HandleSourceCreateSubmit() http.HandlerFunc {
 			return
 		}
 
-		r.Body = http.MaxBytesReader(
-			w, r.Body, 1<<maxBodyShift,
-		)
-
+		// The body size cap is enforced by the MaxBodySize
+		// middleware, which runs before CSRF parses the form.
 		err := r.ParseForm()
 		if err != nil {
 			http.Error(
@@ -386,10 +384,8 @@ func (h *Handlers) HandleSourceEditSubmit() http.HandlerFunc {
 			return
 		}
 
-		r.Body = http.MaxBytesReader(
-			w, r.Body, 1<<maxBodyShift,
-		)
-
+		// The body size cap is enforced by the MaxBodySize
+		// middleware, which runs before CSRF parses the form.
 		err = r.ParseForm()
 		if err != nil {
 			http.Error(
@@ -409,10 +405,8 @@ func (h *Handlers) applyWebhookEdit(
 	r *http.Request,
 	webhook *database.Webhook,
 ) {
-	r.Body = http.MaxBytesReader(
-		w, r.Body, 1<<maxBodyShift,
-	)
-
+	// The body size cap is enforced by the MaxBodySize middleware,
+	// which runs before CSRF parses the form.
 	name := r.FormValue("name")
 	if name == "" {
 		data := map[string]any{
@@ -725,10 +719,8 @@ func (h *Handlers) HandleEntrypointCreate() http.HandlerFunc {
 			return
 		}
 
-		r.Body = http.MaxBytesReader(
-			w, r.Body, 1<<maxBodyShift,
-		)
-
+		// The body size cap is enforced by the MaxBodySize
+		// middleware, which runs before CSRF parses the form.
 		err = r.ParseForm()
 		if err != nil {
 			http.Error(
@@ -785,10 +777,8 @@ func (h *Handlers) HandleTargetCreate() http.HandlerFunc {
 			return
 		}
 
-		r.Body = http.MaxBytesReader(
-			w, r.Body, 1<<maxBodyShift,
-		)
-
+		// The body size cap is enforced by the MaxBodySize
+		// middleware, which runs before CSRF parses the form.
 		err = r.ParseForm()
 		if err != nil {
 			http.Error(
@@ -808,10 +798,8 @@ func (h *Handlers) processTargetCreate(
 	r *http.Request,
 	webhook database.Webhook,
 ) {
-	r.Body = http.MaxBytesReader(
-		w, r.Body, 1<<maxBodyShift,
-	)
-
+	// The body size cap is enforced by the MaxBodySize middleware,
+	// which runs before CSRF parses the form.
 	name := r.FormValue("name")
 	targetType := database.TargetType(r.FormValue("type"))
 	targetURL := r.FormValue("url")

internal/middleware/middleware.go

@@ -285,10 +285,36 @@ func (s *Middleware) NoCache() func(http.Handler) http.Handler {
 	}
 }
 
-// MaxBodySize returns middleware that limits the request body size
-// for POST requests. If the body exceeds the given limit in
-// bytes, the server returns 413 Request Entity Too Large. This
-// prevents clients from sending arbitrarily large form bodies.
+// bodyLimitedMethod reports whether the request method carries a
+// body that the MaxBodySize middleware should cap.
+func bodyLimitedMethod(method string) bool {
+	return method == http.MethodPost ||
+		method == http.MethodPut ||
+		method == http.MethodPatch
+}
+
+// MaxBodySize returns middleware that limits the size of
+// POST/PUT/PATCH request bodies to maxBytes. It must be registered
+// before any middleware that parses the body — notably CSRF, which
+// calls r.PostFormValue — so that form parsing happens under this
+// cap rather than net/http's 10 MB default.
+//
+// Two enforcement paths exist, because http.MaxBytesReader alone
+// cannot produce a 413: it reports the overflow as an error from
+// Read, by which point the body parser downstream has already
+// converted that error into its own response.
+//
+//   - Declared oversize: the request announces a Content-Length
+//     greater than maxBytes. The middleware answers 413 Request
+//     Entity Too Large immediately and does not call the next
+//     handler, so neither CSRF nor the endpoint handler runs.
+//   - Undeclared oversize: the request is chunked (Content-Length
+//     of -1) or lies about its Content-Length. There is nothing to
+//     check up front, so http.MaxBytesReader hard-caps the body at
+//     maxBytes and the request fails downstream — the form parse
+//     errors out and CSRF rejects it with 403. The response is less
+//     precise than a 413, but the body is still never buffered
+//     beyond the cap, which is the property that matters.
 func (s *Middleware) MaxBodySize(
 	maxBytes int64,
 ) func(http.Handler) http.Handler {
@@ -297,14 +323,31 @@ func (s *Middleware) MaxBodySize(
 			w http.ResponseWriter,
 			r *http.Request,
 		) {
-			if r.Method == http.MethodPost ||
-				r.Method == http.MethodPut ||
-				r.Method == http.MethodPatch {
-				r.Body = http.MaxBytesReader(
-					w, r.Body, maxBytes,
-				)
+			if !bodyLimitedMethod(r.Method) {
+				next.ServeHTTP(w, r)
+
+				return
 			}
 
+			if r.ContentLength > maxBytes {
+				s.log.Warn(
+					"request body exceeds limit",
+					"method", r.Method,
+					"path", r.URL.Path,
+					"content_length", r.ContentLength,
+					"limit", maxBytes,
+				)
+				http.Error(
+					w,
+					"Request Entity Too Large",
+					http.StatusRequestEntityTooLarge,
+				)
+
+				return
+			}
+
+			r.Body = http.MaxBytesReader(w, r.Body, maxBytes)
+
 			next.ServeHTTP(w, r)
 		})
 	}

internal/middleware/middleware_test.go

@@ -3,10 +3,12 @@ package middleware_test
 import (
 	"context"
 	"encoding/base64"
+	"io"
 	"log/slog"
 	"net/http"
 	"net/http/httptest"
 	"os"
+	"strings"
 	"testing"
 
 	"github.com/gorilla/sessions"
@@ -426,6 +428,153 @@ func TestNoCache_SetsHeaders(t *testing.T) {
 	)
 }
 
+// --- MaxBodySize Middleware Tests ---
+
+const testBodyLimit int64 = 64
+
+// maxBodySizeHandler wraps a sentinel handler in MaxBodySize with
+// testBodyLimit. The sentinel records whether it ran and how much of
+// the body it managed to read, so tests can distinguish "never
+// reached" from "reached but truncated".
+type maxBodySizeResult struct {
+	called   bool
+	read     int
+	readErr  error
+	response *httptest.ResponseRecorder
+}
+
+func runMaxBodySize(
+	t *testing.T,
+	req *http.Request,
+) *maxBodySizeResult {
+	t.Helper()
+
+	m, _ := testMiddleware(t, config.EnvironmentDev)
+	res := &maxBodySizeResult{response: httptest.NewRecorder()}
+
+	handler := m.MaxBodySize(testBodyLimit)(http.HandlerFunc(
+		func(w http.ResponseWriter, r *http.Request) {
+			res.called = true
+
+			body, err := io.ReadAll(r.Body)
+			res.read = len(body)
+			res.readErr = err
+
+			w.WriteHeader(http.StatusOK)
+		},
+	))
+
+	handler.ServeHTTP(res.response, req)
+
+	return res
+}
+
+// postWithBody builds a POST request whose Content-Length is
+// accurate for the given payload size.
+func postWithBody(size int) *http.Request {
+	req := httptest.NewRequestWithContext(
+		context.Background(),
+		http.MethodPost, "/pages/login",
+		strings.NewReader(strings.Repeat("a", size)),
+	)
+	req.Header.Set(
+		"Content-Type", "application/x-www-form-urlencoded",
+	)
+
+	return req
+}
+
+func TestMaxBodySize_DeclaredOversize_413AndHandlerNotReached(
+	t *testing.T,
+) {
+	t.Parallel()
+
+	res := runMaxBodySize(t, postWithBody(int(testBodyLimit)+1))
+
+	assert.False(
+		t, res.called,
+		"handler must not be reached for an oversized body",
+	)
+	assert.Equal(
+		t, http.StatusRequestEntityTooLarge, res.response.Code,
+	)
+}
+
+func TestMaxBodySize_AtLimit_PassesThrough(t *testing.T) {
+	t.Parallel()
+
+	res := runMaxBodySize(t, postWithBody(int(testBodyLimit)))
+
+	assert.True(
+		t, res.called,
+		"handler should be reached for a body at the limit",
+	)
+	require.NoError(t, res.readErr)
+	assert.Equal(t, int(testBodyLimit), res.read)
+	assert.Equal(t, http.StatusOK, res.response.Code)
+}
+
+func TestMaxBodySize_UnderLimit_PassesThrough(t *testing.T) {
+	t.Parallel()
+
+	res := runMaxBodySize(t, postWithBody(1))
+
+	assert.True(t, res.called)
+	require.NoError(t, res.readErr)
+	assert.Equal(t, 1, res.read)
+	assert.Equal(t, http.StatusOK, res.response.Code)
+}
+
+func TestMaxBodySize_GetWithOversizeBody_NotCapped(t *testing.T) {
+	t.Parallel()
+
+	req := httptest.NewRequestWithContext(
+		context.Background(),
+		http.MethodGet, "/pages/login",
+		strings.NewReader(
+			strings.Repeat("a", int(testBodyLimit)+1),
+		),
+	)
+
+	res := runMaxBodySize(t, req)
+
+	assert.True(
+		t, res.called,
+		"GET requests are not subject to the POST body cap",
+	)
+	require.NoError(t, res.readErr)
+	assert.Equal(t, int(testBodyLimit)+1, res.read)
+}
+
+// TestMaxBodySize_UndeclaredOversize_TruncatedAtCap covers the
+// chunked / lying-Content-Length case: there is nothing to check up
+// front, so the request reaches the handler but MaxBytesReader
+// hard-caps the body and the read fails at the limit.
+func TestMaxBodySize_UndeclaredOversize_TruncatedAtCap(
+	t *testing.T,
+) {
+	t.Parallel()
+
+	req := postWithBody(int(testBodyLimit) + 1)
+	// Simulate a chunked request: no declared length.
+	req.ContentLength = -1
+
+	res := runMaxBodySize(t, req)
+
+	assert.True(
+		t, res.called,
+		"an undeclared oversize body cannot be rejected up front",
+	)
+	require.Error(
+		t, res.readErr,
+		"reading past the cap must fail",
+	)
+	assert.Equal(
+		t, int(testBodyLimit), res.read,
+		"the handler must not see more than the cap",
+	)
+}
+
 // --- Helper Tests ---
 
 func TestIpFromHostPort(t *testing.T) {

internal/server/export_test.go

@@ -0,0 +1,36 @@
+package server
+
+import (
+	"log/slog"
+	"net/http"
+
+	"sneak.berlin/go/webhooker/internal/config"
+	"sneak.berlin/go/webhooker/internal/handlers"
+	"sneak.berlin/go/webhooker/internal/middleware"
+)
+
+// MaxFormBodySizeForTest exposes the form body cap so tests can
+// build requests that sit exactly at, below, and above it.
+const MaxFormBodySizeForTest = maxFormBodySize
+
+// NewRouterForTest builds the real route tree via SetupRoutes with
+// the supplied middleware and handlers, bypassing the fx lifecycle
+// and the HTTP listener. Tests use it so that route-group middleware
+// registration order is exercised exactly as it ships, rather than
+// against a hand-rebuilt chain that could drift from routes.go.
+func NewRouterForTest(
+	log *slog.Logger,
+	cfg *config.Config,
+	mw *middleware.Middleware,
+	h *handlers.Handlers,
+) http.Handler {
+	s := &Server{
+		log:    log,
+		mw:     mw,
+		h:      h,
+		params: ServerParams{Config: cfg},
+	}
+	s.SetupRoutes()
+
+	return s.router
+}

internal/server/routes.go

@@ -90,9 +90,11 @@ func (s *Server) setupRoutes() {
 
 func (s *Server) setupPageRoutes() {
 	s.router.Route("/pages", func(r chi.Router) {
+		// MaxBodySize must precede CSRF: gorilla/csrf parses the
+		// form, so the cap has to be installed before it runs.
+		r.Use(s.mw.MaxBodySize(maxFormBodySize))
 		r.Use(s.mw.CSRF())
 		r.Use(s.mw.NoCache())
-		r.Use(s.mw.MaxBodySize(maxFormBodySize))
 
 		r.Group(func(r chi.Router) {
 			r.Use(s.mw.LoginRateLimit())
@@ -106,6 +108,9 @@ func (s *Server) setupPageRoutes() {
 
 func (s *Server) setupUserRoutes() {
 	s.router.Route("/user/{username}", func(r chi.Router) {
+		// MaxBodySize must precede CSRF: gorilla/csrf parses the
+		// form, so the cap has to be installed before it runs.
+		r.Use(s.mw.MaxBodySize(maxFormBodySize))
 		r.Use(s.mw.CSRF())
 		r.Use(s.mw.NoCache())
 		r.Use(s.mw.RequireAuth())
@@ -118,20 +123,24 @@ func (s *Server) setupUserRoutes() {
 
 func (s *Server) setupSourceRoutes() {
 	s.router.Route("/sources", func(r chi.Router) {
+		// MaxBodySize must precede CSRF: gorilla/csrf parses the
+		// form, so the cap has to be installed before it runs.
+		r.Use(s.mw.MaxBodySize(maxFormBodySize))
 		r.Use(s.mw.CSRF())
 		r.Use(s.mw.NoCache())
 		r.Use(s.mw.RequireAuth())
-		r.Use(s.mw.MaxBodySize(maxFormBodySize))
 		r.Get("/", s.h.HandleSourceList())
 		r.Get("/new", s.h.HandleSourceCreate())
 		r.Post("/new", s.h.HandleSourceCreateSubmit())
 	})
 
 	s.router.Route("/source/{sourceID}", func(r chi.Router) {
+		// MaxBodySize must precede CSRF: gorilla/csrf parses the
+		// form, so the cap has to be installed before it runs.
+		r.Use(s.mw.MaxBodySize(maxFormBodySize))
 		r.Use(s.mw.CSRF())
 		r.Use(s.mw.NoCache())
 		r.Use(s.mw.RequireAuth())
-		r.Use(s.mw.MaxBodySize(maxFormBodySize))
 		r.Get("/", s.h.HandleSourceDetail())
 		r.Get("/edit", s.h.HandleSourceEdit())
 		r.Post("/edit", s.h.HandleSourceEditSubmit())

internal/server/routes_test.go

@@ -0,0 +1,375 @@
+package server_test
+
+import (
+	"context"
+	"html"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"regexp"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"go.uber.org/fx"
+	"go.uber.org/fx/fxtest"
+	"sneak.berlin/go/webhooker/internal/config"
+	"sneak.berlin/go/webhooker/internal/database"
+	"sneak.berlin/go/webhooker/internal/delivery"
+	"sneak.berlin/go/webhooker/internal/globals"
+	"sneak.berlin/go/webhooker/internal/handlers"
+	"sneak.berlin/go/webhooker/internal/healthcheck"
+	"sneak.berlin/go/webhooker/internal/logger"
+	"sneak.berlin/go/webhooker/internal/middleware"
+	"sneak.berlin/go/webhooker/internal/server"
+	"sneak.berlin/go/webhooker/internal/session"
+)
+
+// csrfCookieName is the cookie gorilla/csrf issues when it runs. Its
+// presence or absence on a response is how these tests tell whether
+// the CSRF middleware executed.
+const csrfCookieName = "_gorilla_csrf"
+
+type noopNotifier struct{}
+
+func (n *noopNotifier) Notify([]delivery.Task) {}
+
+// testEnv is the real router from routes.go plus the collaborators
+// tests need to seed users and forge sessions.
+type testEnv struct {
+	router http.Handler
+	sess   *session.Session
+	db     *database.Database
+}
+
+// newTestEnv wires the dependency graph with fx and builds the
+// production route tree, so middleware registration order is
+// exercised exactly as it ships.
+func newTestEnv(t *testing.T) *testEnv {
+	t.Helper()
+
+	var (
+		log  *logger.Logger
+		cfg  *config.Config
+		mw   *middleware.Middleware
+		hnd  *handlers.Handlers
+		sess *session.Session
+		db   *database.Database
+	)
+
+	app := fxtest.New(
+		t,
+		fx.Provide(
+			globals.New,
+			logger.New,
+			func() *config.Config {
+				return &config.Config{
+					DataDir:     t.TempDir(),
+					Environment: config.EnvironmentDev,
+				}
+			},
+			database.New,
+			database.NewWebhookDBManager,
+			healthcheck.New,
+			session.New,
+			func() delivery.Notifier { return &noopNotifier{} },
+			middleware.New,
+			handlers.New,
+		),
+		fx.Populate(&log, &cfg, &mw, &hnd, &sess, &db),
+	)
+	app.RequireStart()
+	t.Cleanup(app.RequireStop)
+
+	return &testEnv{
+		router: server.NewRouterForTest(log.Get(), cfg, mw, hnd),
+		sess:   sess,
+		db:     db,
+	}
+}
+
+// oversizeValue returns a form value one byte past the route-group
+// body cap, so an encoded form containing it is guaranteed oversize.
+func oversizeValue() string {
+	return strings.Repeat("a", int(server.MaxFormBodySizeForTest)+1)
+}
+
+// csrfCookieSet reports whether the response issued a gorilla/csrf
+// cookie, which only happens if the CSRF middleware ran.
+func csrfCookieSet(w *httptest.ResponseRecorder) bool {
+	for _, c := range w.Result().Cookies() {
+		if c.Name == csrfCookieName {
+			return true
+		}
+	}
+
+	return false
+}
+
+// get issues a GET through the router with the supplied cookies.
+func (e *testEnv) get(
+	path string,
+	cookies []*http.Cookie,
+) *httptest.ResponseRecorder {
+	req := httptest.NewRequestWithContext(
+		context.Background(), http.MethodGet, path, nil,
+	)
+
+	for _, c := range cookies {
+		req.AddCookie(c)
+	}
+
+	w := httptest.NewRecorder()
+	e.router.ServeHTTP(w, req)
+
+	return w
+}
+
+// post issues a urlencoded form POST through the router. The body is
+// a strings.Reader, so the request carries an accurate
+// Content-Length — the signal MaxBodySize checks up front.
+func (e *testEnv) post(
+	path string,
+	form url.Values,
+	cookies []*http.Cookie,
+) *httptest.ResponseRecorder {
+	req := httptest.NewRequestWithContext(
+		context.Background(), http.MethodPost, path,
+		strings.NewReader(form.Encode()),
+	)
+	req.Header.Set(
+		"Content-Type", "application/x-www-form-urlencoded",
+	)
+
+	for _, c := range cookies {
+		req.AddCookie(c)
+	}
+
+	w := httptest.NewRecorder()
+	e.router.ServeHTTP(w, req)
+
+	return w
+}
+
+// csrfFrom renders the page at path and returns the CSRF token from
+// its form together with every cookie needed for the follow-up POST.
+func (e *testEnv) csrfFrom(
+	t *testing.T,
+	path string,
+	cookies []*http.Cookie,
+) (string, []*http.Cookie) {
+	t.Helper()
+
+	w := e.get(path, cookies)
+	require.Equal(t, http.StatusOK, w.Code)
+
+	pattern := regexp.MustCompile(
+		`name="csrf_token" value="([^"]+)"`,
+	)
+
+	match := pattern.FindStringSubmatch(w.Body.String())
+	require.Len(t, match, 2, "form must embed a CSRF token")
+
+	// html/template escapes "+" and "=" in attribute values, and
+	// gorilla/csrf tokens are standard base64, so the value read
+	// out of the markup has to be unescaped before it is submitted.
+	token := html.UnescapeString(match[1])
+
+	combined := make([]*http.Cookie, 0, len(cookies))
+	combined = append(combined, cookies...)
+	combined = append(combined, w.Result().Cookies()...)
+
+	return token, combined
+}
+
+// authCookies forges an authenticated session for the given user.
+func (e *testEnv) authCookies(
+	t *testing.T,
+	userID, username string,
+) []*http.Cookie {
+	t.Helper()
+
+	req := httptest.NewRequestWithContext(
+		context.Background(), http.MethodGet, "/setup", nil,
+	)
+	w := httptest.NewRecorder()
+
+	s, err := e.sess.Get(req)
+	require.NoError(t, err)
+
+	e.sess.SetUser(s, userID, username)
+	require.NoError(t, e.sess.Save(req, w, s))
+
+	cookies := w.Result().Cookies()
+	require.NotEmpty(t, cookies, "session cookie should be set")
+
+	return cookies
+}
+
+// seedUser creates a user with the given password and returns the
+// stored hash so tests can assert whether it later changed.
+func (e *testEnv) seedUser(
+	t *testing.T,
+	username, password string,
+) (string, string) {
+	t.Helper()
+
+	hash, err := database.HashPassword(password)
+	require.NoError(t, err)
+
+	user := &database.User{Username: username, Password: hash}
+	require.NoError(t, e.db.DB().Create(user).Error)
+
+	return user.ID, hash
+}
+
+// storedHash reads the current password hash for a username.
+func (e *testEnv) storedHash(t *testing.T, username string) string {
+	t.Helper()
+
+	var user database.User
+
+	require.NoError(t,
+		e.db.DB().Where("username = ?", username).
+			First(&user).Error,
+	)
+
+	return user.Password
+}
+
+// --- /pages group ---
+
+// TestPagesLogin_OversizeBody_RejectedBeforeCSRF proves the cap runs
+// ahead of gorilla/csrf: the response is a clean 413 and no CSRF
+// cookie was issued, so neither the CSRF middleware nor the login
+// handler ran.
+func TestPagesLogin_OversizeBody_RejectedBeforeCSRF(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+
+	form := url.Values{}
+	form.Set("username", oversizeValue())
+	form.Set("password", "irrelevant")
+
+	w := env.post("/pages/login", form, nil)
+
+	assert.Equal(
+		t, http.StatusRequestEntityTooLarge, w.Code,
+	)
+	assert.False(
+		t, csrfCookieSet(w),
+		"CSRF middleware must not run for an oversized body",
+	)
+}
+
+// TestPagesLogin_UnderLimit_NoToken_CSRFRejects is the control for
+// the test above: an identically shaped but under-limit POST does
+// reach gorilla/csrf, which rejects it and issues its cookie. Without
+// this, the missing-cookie assertion above would prove nothing.
+func TestPagesLogin_UnderLimit_NoToken_CSRFRejects(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+
+	form := url.Values{}
+	form.Set("username", "someone")
+	form.Set("password", "irrelevant")
+
+	w := env.post("/pages/login", form, nil)
+
+	assert.Equal(t, http.StatusForbidden, w.Code)
+	assert.True(
+		t, csrfCookieSet(w),
+		"CSRF middleware should run for an under-limit body",
+	)
+}
+
+// TestPagesLogin_UnderLimit_ValidToken_ReachesHandler proves the
+// reorder did not break CSRF token handling: a token harvested from
+// the rendered login form is still accepted and the request lands in
+// the handler.
+func TestPagesLogin_UnderLimit_ValidToken_ReachesHandler(
+	t *testing.T,
+) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+
+	token, cookies := env.csrfFrom(t, "/pages/login", nil)
+
+	form := url.Values{}
+	form.Set("csrf_token", token)
+	form.Set("username", "nosuchuser")
+	form.Set("password", "wrongpassword")
+
+	w := env.post("/pages/login", form, cookies)
+
+	assert.Equal(t, http.StatusUnauthorized, w.Code)
+	assert.Contains(
+		t, w.Body.String(), "Invalid username or password",
+		"request should reach the login handler",
+	)
+}
+
+// --- /user/{username} group ---
+
+// TestPasswordChange_OversizeBody_RejectedAndPasswordUnchanged
+// covers the route that previously had no middleware body cap at
+// all. The request carries a valid session and a valid CSRF token,
+// so the only thing that can stop it is the size cap; the unchanged
+// password hash is the observable proof the handler never ran.
+func TestPasswordChange_OversizeBody_RejectedAndPasswordUnchanged(
+	t *testing.T,
+) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+
+	userID, originalHash := env.seedUser(t, "pwuser", "oldpassword")
+	cookies := env.authCookies(t, userID, "pwuser")
+	token, cookies := env.csrfFrom(t, "/user/pwuser/", cookies)
+
+	form := url.Values{}
+	form.Set("csrf_token", token)
+	form.Set("current_password", "oldpassword")
+	form.Set("new_password", oversizeValue())
+	form.Set("confirm_password", oversizeValue())
+
+	w := env.post("/user/pwuser/password", form, cookies)
+
+	assert.Equal(
+		t, http.StatusRequestEntityTooLarge, w.Code,
+	)
+	assert.Equal(
+		t, originalHash, env.storedHash(t, "pwuser"),
+		"handler must not run, so the password must be unchanged",
+	)
+}
+
+// TestPasswordChange_UnderLimit_Succeeds proves that adding the cap
+// to the /user/{username} group did not break the route it guards.
+func TestPasswordChange_UnderLimit_Succeeds(t *testing.T) {
+	t.Parallel()
+
+	env := newTestEnv(t)
+
+	userID, originalHash := env.seedUser(t, "okuser", "oldpassword")
+	cookies := env.authCookies(t, userID, "okuser")
+	token, cookies := env.csrfFrom(t, "/user/okuser/", cookies)
+
+	form := url.Values{}
+	form.Set("csrf_token", token)
+	form.Set("current_password", "oldpassword")
+	form.Set("new_password", "brandnewpassword")
+	form.Set("confirm_password", "brandnewpassword")
+
+	w := env.post("/user/okuser/password", form, cookies)
+
+	assert.Equal(t, http.StatusOK, w.Code)
+	assert.NotEqual(
+		t, originalHash, env.storedHash(t, "okuser"),
+		"an under-limit password change should still apply",
+	)
+}