Say the proxy is covered by default or by a set value

The rate-limit test comments on trustedProxyCIDR and forwardedKeyFor
said production needs TRUSTED_PROXIES set; another said only
operator-listed addresses are trusted. The README's Rate Limiting
paragraph said "listed in", and the login endpoint section assumed
every proxied deployment shares one bucket. All now match the
RFC 1918 default.

Model: opus-5-5

README.md

@@ -147,7 +147,7 @@ TTY detection, and security headers are always applied.
 | `RETENTION_SWEEP_INTERVAL` | How often the retention reaper and archive sweeper run (Go duration, must be positive) | `1h` |
 | `SESSION_IDLE_TIMEOUT`  | Idle session timeout (Go duration)  | `24h`    |
 | `RECEIVER_RATE_LIMIT`   | Receiver requests/minute per IP per entrypoint (10x that per IP across the route) | `120` |
-| `TRUSTED_PROXIES`       | CIDRs whose forwarded headers are trusted. A set value replaces the default. Under the default, any client with a private address, whether it connects directly or through a trusted proxy, can choose its own rate-limit key by sending its own `X-Forwarded-For`; if any clients have private addresses, set it to the proxy's address alone. See [Trusted proxies](#trusted-proxies) | `10.0.0.0/8,172.16.0.0/12,192.168.0.0/16` (RFC 1918) |
+| `TRUSTED_PROXIES`       | CIDRs whose forwarded headers are trusted. A set value replaces the default. Under the default, any client with a private address, whether it connects directly or through the proxy, can choose its own rate-limit key by sending its own `X-Forwarded-For`; if any clients have private addresses, set it to the proxy's address alone. See [Trusted proxies](#trusted-proxies) | `10.0.0.0/8,172.16.0.0/12,192.168.0.0/16` (RFC 1918) |
 | `ALLOWED_EGRESS_CIDRS`  | CIDRs that delivery targets may reach despite the SSRF blocklist. Read [Allowing egress to your own network](#allowing-egress-to-your-own-network) before setting it | `""` (none) |
 
 #### Allowing egress to your own network
@@ -447,8 +447,8 @@ Two operator requirements follow:
   it can name a different address on every request to get a fresh
   bucket each time, or name another client's address to drain that
   client's bucket. A block that also covers clients — the default, on
-  a network where clients have private addresses — makes every rate
+  a network where clients have private addresses — makes all three
-  limit, including the unauthenticated webhook receiver's, silently
+  limits, including the unauthenticated webhook receiver, silently
   bypassable by every client in the block.
 
 #### Sessions
@@ -1455,7 +1455,7 @@ A registered user of the webhooker service.
 | Field      | Type     | Description |
 | ---------- | -------- | ----------- |
 | `id`       | UUID     | Primary key |
-| `username` | string   | Unique login name, at most 1024 bytes so that it fits in the session cookie |
+| `username` | string   | Unique login name |
 | `password` | string   | Argon2id hash (never exposed via API) |
 
 **Relations:** Has many Webhooks. Has many APIKeys.
@@ -2395,14 +2395,14 @@ Removing either cap fails 14 subtests.
 
 `internal/middleware/logbound_test.go` and
 `internal/handlers/logbound_test.go` drive 8 KB of client-chosen text
-at each of these — just under 1 KB at `invalid password`, whose
+at each of these — 1 KB at `invalid password`, whose accounts are
-accounts are shared with the successful-login line and so must stay
+shared with the successful-login line, where a username past 4 KB
-within the 1024-byte username limit — through both handlers, and
+overflows the session cookie and answers 500 before that line is
-through seven fills: plain text as the baseline, and then the
+written — through both handlers, and through seven fills: plain text
-quotation mark, backslash, tab, newline, C0 control and astral
+as the baseline, and then the quotation mark, backslash, tab, newline,
-non-printable, six characters the wider of the two handlers spends
+C0 control and astral non-printable, six characters the wider of the
-more on than the client spent sending them. Every case holds each
+two handlers spends more on than the client spent sending them. Every
-line to the 2,560-byte ceiling. That per-line ceiling
+case holds each line to the 2,560-byte ceiling. That per-line ceiling
 is what the figure above states, and every row establishes it.
 
 Three of the sites go further and bound the whole flood's output — the
@@ -2552,12 +2552,12 @@ the tree is checked out: four checkouts have reported 3,959, 3,961,
 client-supplied field was cut, and that the shipped chain's stack
 arrived uncut — never the numbers.
 
-Every limiter here — receiver, login, password change, delivery replay
+Every limiter here — receiver, login, and password change — identifies
-and event resubmit — identifies the client the same way, through one
+the client the same way, through one shared key function: the
-shared key function: the connection's own address, unless the peer is
+connection's own address, unless the peer is inside
-inside `TRUSTED_PROXIES`, in which case the forwarded client address is
+`TRUSTED_PROXIES`, in which case the forwarded client address is used
-used instead. That address becomes a bucket by family: IPv4 keys on
+instead. That address becomes a bucket by family: IPv4 keys on the full
-the full address, IPv6 on its `/64` prefix. A routed `/64` is the normal
+address, IPv6 on its `/64` prefix. A routed `/64` is the normal
 residential and mobile IPv6 allocation, so keying IPv6 per address would
 let one subscriber rotate source addresses and mint a fresh bucket per
 request, evading these limits at the network layer without spoofing

internal/config/config.go

@@ -182,9 +182,9 @@ type Config struct {
 	// Other peers' forwarded headers are ignored and they are
 	// identified by the connection's own address. Under the
 	// default any client with a private address, directly or
-	// through a trusted proxy, can choose its own rate-limit
+	// through a proxy, can choose its own rate-limit key, so
-	// key, so where any clients have private addresses this must
+	// where any clients have private addresses this must be set
-	// be set to the proxy hosts alone.
+	// to the proxy hosts alone.
 	TrustedProxies []netip.Prefix
 
 	// AllowedEgressCIDRs is the set of networks a delivery target

internal/database/model_user.go

@@ -1,58 +1,13 @@
 package database
 
-import (
-	"errors"
-	"fmt"
-
-	"gorm.io/gorm"
-)
-
-// MaxUsernameBytes is the longest username, in bytes, that a user may
-// have. The same number appears in the check constraint on
-// User.Username, because a struct tag cannot reference a constant.
-//
-// A login stores the username in the session cookie, and both
-// securecookie and browsers refuse a cookie value past about 4096
-// bytes. That value is the session base64-encoded twice, so it holds
-// 4096 × 3/4 × 3/4 = 2304 bytes of session, and the signature,
-// timestamp and the session's other values take about 270 of those: a
-// username longer than about 2030 bytes can never log in. The limit is
-// about half that, so the session can carry more values later without
-// locking out an account whose username is already at the limit.
-const MaxUsernameBytes = 1024
-
-// ErrUsernameTooLong is returned when a user is saved with a username
-// longer than MaxUsernameBytes.
-var ErrUsernameTooLong = errors.New("username is too long")
-
 // User represents a user of the webhooker service
-//
-//nolint:lll // a struct tag cannot wrap
 type User struct {
 	BaseModel
 
-	Username string `gorm:"uniqueIndex;not null;check:length(CAST(username AS BLOB)) <= 1024" json:"username"`
+	Username string `gorm:"uniqueIndex;not null" json:"username"`
-	Password string `gorm:"not null"                                                          json:"-"` // Argon2 hashed
+	Password string `gorm:"not null"             json:"-"` // Argon2 hashed
 
 	// Relations
 	Webhooks []Webhook `json:"webhooks,omitempty"`
 	APIKeys  []APIKey  `json:"apiKeys,omitempty"`
 }
-
-// BeforeSave rejects a username longer than MaxUsernameBytes when a whole
-// User is created or saved, so those calls get ErrUsernameTooLong rather
-// than the database's constraint error. A column update such as
-// Update("username", ...) is caught only by the check constraint, as is
-// any path that writes the table without this model.
-func (u *User) BeforeSave(_ *gorm.DB) error {
-	if len(u.Username) > MaxUsernameBytes {
-		return fmt.Errorf(
-			"%w: %d bytes, limit is %d",
-			ErrUsernameTooLong,
-			len(u.Username),
-			MaxUsernameBytes,
-		)
-	}
-
-	return nil
-}

internal/database/model_user_test.go

@@ -1,65 +0,0 @@
-package database_test
-
-import (
-	"strings"
-	"testing"
-
-	"github.com/google/uuid"
-	"github.com/stretchr/testify/assert"
-	"github.com/stretchr/testify/require"
-	"sneak.berlin/go/webhooker/internal/database"
-)
-
-// usernameAtLimit is exactly MaxUsernameBytes long, built from a
-// two-byte character. A check that counted characters rather than bytes
-// would see half the length and let the one-byte-longer name through.
-func usernameAtLimit() string {
-	return strings.Repeat("é", database.MaxUsernameBytes/2)
-}
-
-func TestUserCreate_RejectsOverlongUsername(t *testing.T) {
-	t.Parallel()
-
-	db := startedTestDB(t)
-
-	err := db.Create(&database.User{
-		Username: usernameAtLimit() + "x",
-		Password: "hash",
-	}).Error
-
-	require.ErrorIs(t, err, database.ErrUsernameTooLong)
-}
-
-func TestUserCreate_AcceptsUsernameAtLimit(t *testing.T) {
-	t.Parallel()
-
-	db := startedTestDB(t)
-
-	require.NoError(t, db.Create(&database.User{
-		Username: usernameAtLimit(),
-		Password: "hash",
-	}).Error)
-}
-
-// TestUsersTable_EnforcesUsernameLimitWithoutTheModel inserts with raw
-// SQL, as a path that bypassed User.BeforeSave would, so only the
-// table's check constraint stands between it and an over-long
-// username. Accepting the name at the limit and refusing the next byte
-// also pins the constraint's number to MaxUsernameBytes.
-func TestUsersTable_EnforcesUsernameLimitWithoutTheModel(t *testing.T) {
-	t.Parallel()
-
-	db := startedTestDB(t)
-
-	insert := "INSERT INTO users (id, username, password) VALUES (?, ?, ?)"
-
-	require.NoError(t, db.Exec(
-		insert, uuid.New().String(), usernameAtLimit(), "hash",
-	).Error)
-
-	err := db.Exec(
-		insert, uuid.New().String(), usernameAtLimit()+"x", "hash",
-	).Error
-	require.Error(t, err)
-	assert.Contains(t, err.Error(), "CHECK constraint failed")
-}

internal/handlers/auth_test.go

@@ -453,33 +453,3 @@ func TestLogin_SuccessCreatesSession(t *testing.T) {
 		"the issued cookie must carry an authenticated session",
 	)
 }
-
-// TestLogin_UsernameAtLimitCanLogIn shows that a username of exactly
-// database.MaxUsernameBytes still fits in the session cookie. Past
-// what the cookie can carry, a correct login answers 500.
-func TestLogin_UsernameAtLimitCanLogIn(t *testing.T) {
-	t.Parallel()
-
-	var (
-		h  *handlers.Handlers
-		db *database.Database
-	)
-
-	app := newTestApp(t, &h, &db)
-	app.RequireStart()
-
-	t.Cleanup(app.RequireStop)
-
-	username := strings.Repeat("a", database.MaxUsernameBytes)
-
-	hash, err := database.HashPassword(operatorPassword)
-	require.NoError(t, err)
-	require.NoError(t, db.DB().Create(&database.User{
-		Username: username,
-		Password: hash,
-	}).Error)
-
-	w := submitLogin(h, sharedProxyPeer, username, operatorPassword)
-
-	assert.Equal(t, http.StatusSeeOther, w.Code)
-}

internal/handlers/logbound_test.go

@@ -339,9 +339,11 @@ const storedUserPassword = "correct-horse-battery-staple"
 // storedFillBytes is the raw length of the client-chosen value in
 // those accounts' usernames. It is well past the 512-byte field
 // budget, so the line is still truncated, but short enough that the
-// whole username, markers and fill name included, stays within
+// session cookie a successful login writes stays inside
-// database.MaxUsernameBytes.
+// securecookie's 4 KB limit: the cookie is written BEFORE the
-const storedFillBytes = 960
+// "user logged in" line, so an 8 KB username answers 500 and never
+// reaches it.
+const storedFillBytes = 1024
 
 // storedFill builds a username fill of storedFillBytes raw bytes out
 // of repetitions of ch, with both markers at its far end.