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Derive every key from the signing key in one place (closes #315) #332

Merged
clawbot merged 1 commits from issue-315-derive-keys-in-one-place into next 2026-10-26 14:10:22 +01:00
Conversation 1 Commits 1 Files Changed 27
+295 -152
27 changed files with 295 additions and 152 deletions
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README.md
+11 -1
View File
@@ -765,7 +765,17 @@ Key settings in more detail:
duration; default `60s`. The upstream fetch counts toward it, and so do the
waits for an upstream connection and for a processing slot (up to 10 seconds
each), so keep it longer than `upstream_fetch_timeout` plus 20 seconds
- `signing_key` — HMAC secret for URL signatures
- `signing_key` — the secret that protects signed URLs, encrypted URLs and
logins. pixa uses it as it is for two things:
- the HMAC key of signed URLs (see Signature Specification)
- the password of the login page
pixa derives every other key it uses from it at startup, with HKDF-SHA256:
- a key that signs the session cookie
- a key that encrypts the session cookie
- a key that encrypts the token of an encrypted URL
- a key that signs the CSRF token cookie of the login and generator pages
- `db_url` — the SQLite database to open; omitted, it is
`file:<state_dir>/state.sqlite3?_pragma=journal_mode(WAL)`, which keeps the
database in WAL mode. `state_dir` is percent-encoded in it, so a `%`, `?` or
TODO.md
+11
View File
@@ -30,6 +30,17 @@ P2: security: per-origin rate limiting
# Completed Steps
- 2026-10-26 every key derived from the signing key is derived in one place
(closes #315): `seal.DeriveKeys` returns them as one `seal.Keys`, with their
salts declared beside it. `internal/providers` calls it once at startup. Each
key is derived as before, with `seal.DeriveKey` and the same salt.
- The session manager, the encrypted URL generator and the CSRF protection
each take their own key instead of the signing key.
- `session.NewManager`, `encurl.NewGenerator`, `newCSRFProtect` and
`handlers.New` return no error, as nothing in them can fail now.
- The signing key itself stays the HMAC key of signed URLs and the login
password.
- `README.md` says under `signing_key` what it protects.
- 2026-10-26 the image request holds only what names the cached object (closes
#314): its source and its transform, which the variant key covers. The signed
URL format, the signing algorithm and every route's answers are unchanged.
internal/encurl/encurl.go
+4 -12
View File
@@ -16,9 +16,6 @@ const (
DefaultQuality = 85
DefaultFormat = imagerequest.FormatJXL
DefaultFitMode = imagerequest.FitCover
// HKDF salt for URL encryption key derivation
urlKeySalt = "pixa-urlenc-v1"
)
// Errors returned by encurl operations.
@@ -48,15 +45,10 @@ type Generator struct {
key [seal.KeySize]byte
}
// NewGenerator creates an encrypted URL generator with a key derived
// from the signing key.
func NewGenerator(signingKey string) (*Generator, error) {
key, err := seal.DeriveKey([]byte(signingKey), urlKeySalt)
if err != nil {
return nil, err
}
return &Generator{key: key}, nil
// NewGenerator creates an encrypted URL generator that encrypts its tokens
// with key.
func NewGenerator(key [seal.KeySize]byte) *Generator {
return &Generator{key: key}
}
// Generate creates an encrypted URL token from the request's source and
internal/encurl/encurl_test.go
+19 -9
View File
@@ -7,6 +7,7 @@ import (
"sneak.berlin/go/pixa/internal/encurl"
"sneak.berlin/go/pixa/internal/imagerequest"
"sneak.berlin/go/pixa/internal/seal"
)
// Shared test fixture strings.
@@ -19,11 +20,13 @@ const (
func TestGenerator_GenerateAndParse(t *testing.T) {
t.Parallel()
gen, err := encurl.NewGenerator("test-signing-key-12345")
keys, err := seal.DeriveKeys("test-signing-key-12345")
if err != nil {
t.Fatalf("NewGenerator() error = %v", err)
t.Fatalf("seal.DeriveKeys() error = %v", err)
}
gen := encurl.NewGenerator(keys.EncryptedURLKey)
req := &imagerequest.Request{
Source: imagerequest.Source{
Host: testSourceHost,
@@ -99,7 +102,8 @@ func TestGenerator_GenerateAndParse(t *testing.T) {
func TestGenerator_Parse_Expired(t *testing.T) {
t.Parallel()
gen, _ := encurl.NewGenerator("test-signing-key-12345")
keys, _ := seal.DeriveKeys("test-signing-key-12345")
gen := encurl.NewGenerator(keys.EncryptedURLKey)
req := &imagerequest.Request{
Source: imagerequest.Source{
@@ -126,7 +130,8 @@ func TestGenerator_Parse_Expired(t *testing.T) {
func TestGenerator_Parse_InvalidToken(t *testing.T) {
t.Parallel()
gen, _ := encurl.NewGenerator("test-signing-key-12345")
keys, _ := seal.DeriveKeys("test-signing-key-12345")
gen := encurl.NewGenerator(keys.EncryptedURLKey)
_, _, err := gen.Parse("not-a-valid-token")
if err == nil {
@@ -137,7 +142,8 @@ func TestGenerator_Parse_InvalidToken(t *testing.T) {
func TestGenerator_Parse_TamperedToken(t *testing.T) {
t.Parallel()
gen, _ := encurl.NewGenerator("test-signing-key-12345")
keys, _ := seal.DeriveKeys("test-signing-key-12345")
gen := encurl.NewGenerator(keys.EncryptedURLKey)
req := &imagerequest.Request{
Source: imagerequest.Source{
@@ -163,8 +169,10 @@ func TestGenerator_Parse_TamperedToken(t *testing.T) {
func TestGenerator_Parse_WrongKey(t *testing.T) {
t.Parallel()
gen1, _ := encurl.NewGenerator("signing-key-1")
gen2, _ := encurl.NewGenerator("signing-key-2")
keys1, _ := seal.DeriveKeys("signing-key-1")
keys2, _ := seal.DeriveKeys("signing-key-2")
gen1 := encurl.NewGenerator(keys1.EncryptedURLKey)
gen2 := encurl.NewGenerator(keys2.EncryptedURLKey)
req := &imagerequest.Request{
Source: imagerequest.Source{
@@ -184,7 +192,8 @@ func TestGenerator_Parse_WrongKey(t *testing.T) {
func TestGenerator_Parse_Defaults(t *testing.T) {
t.Parallel()
gen, _ := encurl.NewGenerator("test-signing-key-12345")
keys, _ := seal.DeriveKeys("test-signing-key-12345")
gen := encurl.NewGenerator(keys.EncryptedURLKey)
// Request with only required fields - should get defaults
token, err := gen.Generate(&imagerequest.Request{
@@ -221,7 +230,8 @@ func TestGenerator_Parse_Defaults(t *testing.T) {
func TestGenerator_TokenIsURLSafe(t *testing.T) {
t.Parallel()
gen, _ := encurl.NewGenerator("test-signing-key-12345")
keys, _ := seal.DeriveKeys("test-signing-key-12345")
gen := encurl.NewGenerator(keys.EncryptedURLKey)
req := &imagerequest.Request{
Source: imagerequest.Source{
internal/handlers/auth_csrf_internal_test.go
+6 -15
View File
@@ -14,6 +14,7 @@ import (
"sneak.berlin/go/pixa/internal/config"
"sneak.berlin/go/pixa/internal/encurl"
"sneak.berlin/go/pixa/internal/seal"
"sneak.berlin/go/pixa/internal/session"
)
@@ -44,27 +45,17 @@ func newCSRFTestRouter(t *testing.T) (*Handlers, http.Handler) {
cfg := &config.Config{SigningKey: testSigningKey, Debug: true}
sessMgr, err := session.NewManager(testSigningKey)
keys, err := seal.DeriveKeys(testSigningKey)
if err != nil {
t.Fatalf("session.NewManager() error = %v", err)
}
encGen, err := encurl.NewGenerator(testSigningKey)
if err != nil {
t.Fatalf("encurl.NewGenerator() error = %v", err)
}
protect, err := newCSRFProtect(testSigningKey, cfg.Debug)
if err != nil {
t.Fatalf("newCSRFProtect() error = %v", err)
t.Fatalf("seal.DeriveKeys() error = %v", err)
}
h := &Handlers{
log: slog.New(slog.DiscardHandler),
config: cfg,
sessMgr: sessMgr,
encGen: encGen,
csrfProtect: protect,
sessMgr: session.NewManager(keys.SessionHashKey, keys.SessionBlockKey),
encGen: encurl.NewGenerator(keys.EncryptedURLKey),
csrfProtect: newCSRFProtect(keys.CSRFKey, cfg.Debug),
}
r := chi.NewRouter()
internal/handlers/auth_login_log_internal_test.go
+4 -3
View File
@@ -10,6 +10,7 @@ import (
"testing"
"sneak.berlin/go/pixa/internal/config"
"sneak.berlin/go/pixa/internal/seal"
"sneak.berlin/go/pixa/internal/session"
)
@@ -22,15 +23,15 @@ func TestLoginLogLeavesOutSubmittedKey(t *testing.T) {
var buf bytes.Buffer
sessMgr, err := session.NewManager(testSigningKey)
keys, err := seal.DeriveKeys(testSigningKey)
if err != nil {
t.Fatalf("session.NewManager() error = %v", err)
t.Fatalf("seal.DeriveKeys() error = %v", err)
}
h := &Handlers{
log: slog.New(slog.NewJSONHandler(&buf, nil)),
config: &config.Config{SigningKey: testSigningKey},
sessMgr: sessMgr,
sessMgr: session.NewManager(keys.SessionHashKey, keys.SessionBlockKey),
}
submittedKeys := []string{wrongKey, testSigningKey}
internal/handlers/auth_session_internal_test.go
+7 -1
View File
@@ -11,6 +11,7 @@ import (
"time"
"sneak.berlin/go/pixa/internal/imagerequest"
"sneak.berlin/go/pixa/internal/seal"
"sneak.berlin/go/pixa/internal/session"
)
@@ -232,8 +233,13 @@ func TestHandleLogout_SaveFails_Answers500(t *testing.T) {
db := setupTestDB(t)
keys, err := seal.DeriveKeys(testSigningKey)
if err != nil {
t.Fatalf("seal.DeriveKeys() error = %v", err)
}
sessMgr, err := session.NewManagerWithDatabase(
t.Context(), testSigningKey, db)
t.Context(), keys.SessionHashKey, keys.SessionBlockKey, db)
if err != nil {
t.Fatalf("session.NewManagerWithDatabase() error = %v", err)
}
internal/handlers/bodylimit_internal_test.go
+6 -15
View File
@@ -11,6 +11,7 @@ import (
"sneak.berlin/go/pixa/internal/config"
"sneak.berlin/go/pixa/internal/encurl"
"sneak.berlin/go/pixa/internal/seal"
"sneak.berlin/go/pixa/internal/session"
)
@@ -32,27 +33,17 @@ func newBodyLimitTestRouter(
cfg := &config.Config{SigningKey: testSigningKey, Debug: true}
sessMgr, err := session.NewManager(testSigningKey)
keys, err := seal.DeriveKeys(testSigningKey)
if err != nil {
t.Fatalf("session.NewManager() error = %v", err)
}
encGen, err := encurl.NewGenerator(testSigningKey)
if err != nil {
t.Fatalf("encurl.NewGenerator() error = %v", err)
}
protect, err := newCSRFProtect(testSigningKey, cfg.Debug)
if err != nil {
t.Fatalf("newCSRFProtect() error = %v", err)
t.Fatalf("seal.DeriveKeys() error = %v", err)
}
h := &Handlers{
log: slog.New(slog.DiscardHandler),
config: cfg,
sessMgr: sessMgr,
encGen: encGen,
csrfProtect: protect,
sessMgr: session.NewManager(keys.SessionHashKey, keys.SessionBlockKey),
encGen: encurl.NewGenerator(keys.EncryptedURLKey),
csrfProtect: newCSRFProtect(keys.CSRFKey, cfg.Debug),
}
r := chi.NewRouter()
internal/handlers/cache_hit_internal_test.go
+5 -2
View File
@@ -25,6 +25,7 @@ import (
"sneak.berlin/go/pixa/internal/imageprocessor"
"sneak.berlin/go/pixa/internal/imagerequest"
"sneak.berlin/go/pixa/internal/imgcache"
"sneak.berlin/go/pixa/internal/seal"
"sneak.berlin/go/pixa/internal/signature"
)
@@ -146,11 +147,13 @@ func newCountingDatabaseServer(
tb.Fatalf("imgcache.NewService() error = %v", err)
}
encGen, err := encurl.NewGenerator(testSigningKey)
keys, err := seal.DeriveKeys(testSigningKey)
if err != nil {
tb.Fatalf("encurl.NewGenerator() error = %v", err)
tb.Fatalf("seal.DeriveKeys() error = %v", err)
}
encGen := encurl.NewGenerator(keys.EncryptedURLKey)
token, err := encGen.Generate(&imagerequest.Request{
Source: imagerequest.Source{Host: countingHost, Path: photoPath},
Transform: imagerequest.Transform{
internal/handlers/csrf.go
+5 -15
View File
@@ -9,15 +9,10 @@ import (
"sneak.berlin/go/pixa/internal/seal"
)
// csrfKeySalt provides domain separation for the CSRF authentication key,
// derived from the signing key so tokens survive restarts without extra
// configuration and never reuse the session or encrypted-URL key material.
const csrfKeySalt = "pixa-csrf-v1"
// newCSRFProtect builds the CSRF-protection middleware for the
// state-mutating HTML form routes. The token lives in its own cookie,
// independent of the session cookie, so it also protects the login POST
// where no session exists yet (login CSRF).
// where no session exists yet (login CSRF). key signs that cookie.
//
// When plaintext is true (local HTTP development), requests are marked
// plaintext so the library neither demands an https Referer nor sets a
@@ -25,13 +20,8 @@ const csrfKeySalt = "pixa-csrf-v1"
// service runs behind a TLS-terminating proxy, so plaintext is false and
// the library enforces its https Referer origin check.
func newCSRFProtect(
signingKey string, plaintext bool,
) (func(http.Handler) http.Handler, error) {
key, err := seal.DeriveKey([]byte(signingKey), csrfKeySalt)
if err != nil {
return nil, err
}
key [seal.KeySize]byte, plaintext bool,
) func(http.Handler) http.Handler {
protect := csrf.Protect(
key[:],
csrf.Path("/"),
@@ -40,7 +30,7 @@ func newCSRFProtect(
)
if !plaintext {
return protect, nil
return protect
}
return func(next http.Handler) http.Handler {
@@ -49,7 +39,7 @@ func newCSRFProtect(
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
protected.ServeHTTP(w, csrf.PlaintextHTTPRequest(r))
})
}, nil
}
}
// CSRF returns the CSRF-protection middleware for the login and generator
internal/handlers/first_bytes_internal_test.go
+5 -2
View File
@@ -19,6 +19,7 @@ import (
"sneak.berlin/go/pixa/internal/imageprocessor"
"sneak.berlin/go/pixa/internal/imagerequest"
"sneak.berlin/go/pixa/internal/imgcache"
"sneak.berlin/go/pixa/internal/seal"
"sneak.berlin/go/pixa/internal/signature"
)
@@ -60,11 +61,13 @@ func newRoutesFetchingThrough(
t.Fatalf("imgcache.NewService() error = %v", err)
}
encGen, err := encurl.NewGenerator(testSigningKey)
keys, err := seal.DeriveKeys(testSigningKey)
if err != nil {
t.Fatalf("encurl.NewGenerator() error = %v", err)
t.Fatalf("seal.DeriveKeys() error = %v", err)
}
encGen := encurl.NewGenerator(keys.EncryptedURLKey)
h := &Handlers{
log: log,
imgSvc: svc,
internal/handlers/handlers.go
+5 -8
View File
@@ -15,6 +15,7 @@ import (
"sneak.berlin/go/pixa/internal/healthcheck"
"sneak.berlin/go/pixa/internal/imgcache"
"sneak.berlin/go/pixa/internal/logger"
"sneak.berlin/go/pixa/internal/seal"
"sneak.berlin/go/pixa/internal/session"
"sneak.berlin/go/pixa/internal/signature"
)
@@ -26,6 +27,7 @@ type Params struct {
Logger *logger.Logger
Healthcheck *healthcheck.Healthcheck
Config *config.Config
Keys seal.Keys
ImageService *imgcache.Service
SessionManager *session.Manager
@@ -53,12 +55,7 @@ type Handlers struct {
}
// New creates a new Handlers instance.
func New(_ fx.Lifecycle, params Params) (*Handlers, error) {
csrfProtect, err := newCSRFProtect(params.Config.SigningKey, params.Config.Debug)
if err != nil {
return nil, err
}
func New(_ fx.Lifecycle, params Params) *Handlers {
return &Handlers{
log: params.Logger.Get(),
hc: params.Healthcheck,
@@ -66,11 +63,11 @@ func New(_ fx.Lifecycle, params Params) (*Handlers, error) {
imgSvc: params.ImageService,
sessMgr: params.SessionManager,
encGen: params.EncryptedURLGenerator,
csrfProtect: csrfProtect,
csrfProtect: newCSRFProtect(params.Keys.CSRFKey, params.Config.Debug),
signer: signature.New(params.Config.SigningKey),
allowlist: allowlist.New(params.Config.AllowlistHosts),
refererBlocklist: allowlist.New(params.Config.RefererBlocklist),
}, nil
}
}
// WaitForProcessing waits until no image is being processed, or until ctx
internal/handlers/image_cache_control_internal_test.go
+5 -2
View File
@@ -19,6 +19,7 @@ import (
"sneak.berlin/go/pixa/internal/imageprocessor"
"sneak.berlin/go/pixa/internal/imagerequest"
"sneak.berlin/go/pixa/internal/imgcache"
"sneak.berlin/go/pixa/internal/seal"
"sneak.berlin/go/pixa/internal/signature"
)
@@ -61,11 +62,13 @@ func newSignedHostServer(
t.Fatalf("imgcache.NewService() error = %v", err)
}
encGen, err := encurl.NewGenerator(testSigningKey)
keys, err := seal.DeriveKeys(testSigningKey)
if err != nil {
t.Fatalf("encurl.NewGenerator() error = %v", err)
t.Fatalf("seal.DeriveKeys() error = %v", err)
}
encGen := encurl.NewGenerator(keys.EncryptedURLKey)
h := &Handlers{
log: log,
imgSvc: svc,
internal/handlers/imageenc_internal_test.go
+5 -2
View File
@@ -12,6 +12,7 @@ import (
"sneak.berlin/go/pixa/internal/encurl"
"sneak.berlin/go/pixa/internal/imagerequest"
"sneak.berlin/go/pixa/internal/seal"
)
// newEncTestServer builds a router serving the encrypted-URL route with a
@@ -21,11 +22,13 @@ import (
func newEncTestServer(t *testing.T) (*encurl.Generator, http.Handler) {
t.Helper()
encGen, err := encurl.NewGenerator(testSigningKey)
keys, err := seal.DeriveKeys(testSigningKey)
if err != nil {
t.Fatalf("encurl.NewGenerator() error = %v", err)
t.Fatalf("seal.DeriveKeys() error = %v", err)
}
encGen := encurl.NewGenerator(keys.EncryptedURLKey)
h := &Handlers{
log: slog.New(slog.DiscardHandler),
encGen: encGen,
internal/handlers/imageenc_token_internal_test.go
+5 -2
View File
@@ -10,6 +10,7 @@ import (
"sneak.berlin/go/pixa/internal/encurl"
"sneak.berlin/go/pixa/internal/imagerequest"
"sneak.berlin/go/pixa/internal/seal"
)
// requireServedPhoto requires that rec answers 200 with the JPEG at photoPath
@@ -80,11 +81,13 @@ func TestHandleImageEnc_RejectedToken(t *testing.T) {
t.Fatalf("Generate() error = %v", err)
}
otherGen, err := encurl.NewGenerator("another-signing-key-fedcba9876543210")
keys, err := seal.DeriveKeys("another-signing-key-fedcba9876543210")
if err != nil {
t.Fatalf("encurl.NewGenerator() error = %v", err)
t.Fatalf("seal.DeriveKeys() error = %v", err)
}
otherGen := encurl.NewGenerator(keys.EncryptedURLKey)
otherKey, err := otherGen.Generate(&photo, time.Time{})
if err != nil {
t.Fatalf("Generate() error = %v", err)
internal/handlers/referer_blocklist_internal_test.go
+5 -2
View File
@@ -17,6 +17,7 @@ import (
"sneak.berlin/go/pixa/internal/imageprocessor"
"sneak.berlin/go/pixa/internal/imagerequest"
"sneak.berlin/go/pixa/internal/imgcache"
"sneak.berlin/go/pixa/internal/seal"
"sneak.berlin/go/pixa/internal/signature"
)
@@ -73,11 +74,13 @@ func newRefererRoutes(t *testing.T) (http.Handler, *Handlers, *countingFetcher)
t.Fatalf("imgcache.NewService() error = %v", err)
}
encGen, err := encurl.NewGenerator(testSigningKey)
keys, err := seal.DeriveKeys(testSigningKey)
if err != nil {
t.Fatalf("encurl.NewGenerator() error = %v", err)
t.Fatalf("seal.DeriveKeys() error = %v", err)
}
encGen := encurl.NewGenerator(keys.EncryptedURLKey)
h := &Handlers{
log: slog.New(slog.DiscardHandler),
imgSvc: svc,
internal/providers/providers.go
+20 -10
View File
@@ -1,5 +1,6 @@
// Package providers builds from the config the parts pixad serves images
// and logins with, and provides them to the fx graph:
// - the keys derived from the signing key
// - the image cache, with its default limit
// - the fetcher
// - the processor
@@ -27,6 +28,7 @@ import (
"sneak.berlin/go/pixa/internal/imageprocessor"
"sneak.berlin/go/pixa/internal/imgcache"
"sneak.berlin/go/pixa/internal/logger"
"sneak.berlin/go/pixa/internal/seal"
"sneak.berlin/go/pixa/internal/session"
)
@@ -35,6 +37,7 @@ import (
// the cache registers its counters on.
func Constructors() []any {
return []any{
newKeys,
newCache,
newFetcherConfig,
httpfetcher.New,
@@ -45,6 +48,12 @@ func Constructors() []any {
}
}
// newKeys derives the keys of seal.Keys from the signing key. fx calls it
// once, at startup.
func newKeys(cfg *config.Config) (seal.Keys, error) {
return seal.DeriveKeys(cfg.SigningKey)
}
// cacheParams defines dependencies for newCache.
type cacheParams struct {
fx.In
@@ -229,22 +238,23 @@ func newImageService(
type sessionManagerParams struct {
fx.In
Config *config.Config
Keys seal.Keys
Database *database.Database
}
// newSessionManager builds the session manager. Session cookies are
// always Secure, HttpOnly and SameSite=Strict. The random value that each
// logout replaces is saved in the database, so it outlasts a restart.
// newSessionManager builds the session manager with its two keys. Session
// cookies are always Secure, HttpOnly and SameSite=Strict. The random value
// that each logout replaces is saved in the database, so it outlasts a
// restart.
func newSessionManager(
_ fx.Lifecycle, params sessionManagerParams,
) (*session.Manager, error) {
return session.NewManagerWithDatabase(
context.Background(), params.Config.SigningKey, params.Database.DB())
return session.NewManagerWithDatabase(context.Background(),
params.Keys.SessionHashKey, params.Keys.SessionBlockKey,
params.Database.DB())
}
// newEncryptedURLGenerator builds the encrypted URL generator, with a key
// derived from the signing key.
func newEncryptedURLGenerator(cfg *config.Config) (*encurl.Generator, error) {
return encurl.NewGenerator(cfg.SigningKey)
// newEncryptedURLGenerator builds the encrypted URL generator with its key.
func newEncryptedURLGenerator(keys seal.Keys) *encurl.Generator {
return encurl.NewGenerator(keys.EncryptedURLKey)
}
internal/seal/keys.go
+57
View File
@@ -0,0 +1,57 @@
package seal
// The salt of each key that DeriveKeys derives. Each key has a salt of its
// own, so no two uses share a key.
const (
sessionHashKeySalt = "pixa-session-hash-v1"
sessionBlockKeySalt = "pixa-session-block-v1"
encryptedURLKeySalt = "pixa-urlenc-v1"
csrfKeySalt = "pixa-csrf-v1"
)
// Keys holds the keys derived from the signing key, one for each use. The
// signing key itself is used for two things only: it is the HMAC key of signed
// URLs and the password of the login page.
type Keys struct {
// SessionHashKey signs the session cookie.
SessionHashKey [KeySize]byte
// SessionBlockKey encrypts the session cookie.
SessionBlockKey [KeySize]byte
// EncryptedURLKey encrypts the token of an encrypted URL.
EncryptedURLKey [KeySize]byte
// CSRFKey signs the CSRF token cookie of the login and generator pages.
CSRFKey [KeySize]byte
}
// DeriveKeys derives each key of Keys from signingKey, with DeriveKey and the
// salt of that key.
func DeriveKeys(signingKey string) (Keys, error) {
masterKey := []byte(signingKey)
sessionHashKey, err := DeriveKey(masterKey, sessionHashKeySalt)
if err != nil {
return Keys{}, err
}
sessionBlockKey, err := DeriveKey(masterKey, sessionBlockKeySalt)
if err != nil {
return Keys{}, err
}
encryptedURLKey, err := DeriveKey(masterKey, encryptedURLKeySalt)
if err != nil {
return Keys{}, err
}
csrfKey, err := DeriveKey(masterKey, csrfKeySalt)
if err != nil {
return Keys{}, err
}
return Keys{
SessionHashKey: sessionHashKey,
SessionBlockKey: sessionBlockKey,
EncryptedURLKey: encryptedURLKey,
CSRFKey: csrfKey,
}, nil
}
internal/seal/keys_test.go
+42
View File
@@ -0,0 +1,42 @@
package seal_test
import (
"bytes"
"testing"
"sneak.berlin/go/pixa/internal/seal"
)
// TestDeriveKeys_KeysDiffer verifies that the keys DeriveKeys derives differ
// from each other and from the signing key.
func TestDeriveKeys_KeysDiffer(t *testing.T) {
t.Parallel()
// 32 bytes, as long as a derived key, so that no key differs from it by
// its length alone
const signingKey = "0123456789abcdef0123456789abcdef"
keys, err := seal.DeriveKeys(signingKey)
if err != nil {
t.Fatalf("DeriveKeys() error = %v", err)
}
named := []struct {
name string
key []byte
}{
{"the signing key", []byte(signingKey)},
{"SessionHashKey", keys.SessionHashKey[:]},
{"SessionBlockKey", keys.SessionBlockKey[:]},
{"EncryptedURLKey", keys.EncryptedURLKey[:]},
{"CSRFKey", keys.CSRFKey[:]},
}
for i, a := range named {
for _, b := range named[i+1:] {
if bytes.Equal(a.key, b.key) {
t.Errorf("%s equals %s", a.name, b.name)
}
}
}
}
internal/server/computed_side_internal_test.go
+5 -2
View File
@@ -11,6 +11,7 @@ import (
"sneak.berlin/go/pixa/internal/encurl"
"sneak.berlin/go/pixa/internal/imagerequest"
"sneak.berlin/go/pixa/internal/seal"
)
// TestImageProxyRefusesComputedSideAboveMaximum requests sizes of a 3000x600
@@ -48,11 +49,13 @@ func TestImageProxyRefusesComputedSideAboveMaximum(t *testing.T) {
s, _, _ := startImageProxy(t, upstream)
generator, err := encurl.NewGenerator(testSigningKey)
keys, err := seal.DeriveKeys(testSigningKey)
if err != nil {
t.Fatalf("encurl.NewGenerator: %v", err)
t.Fatalf("seal.DeriveKeys: %v", err)
}
generator := encurl.NewGenerator(keys.EncryptedURLKey)
tests := []struct {
path string
// size is the size of the /v1/image/ URL, and width and height are
internal/server/fit_outside_internal_test.go
+5 -2
View File
@@ -9,6 +9,7 @@ import (
"sneak.berlin/go/pixa/internal/encurl"
"sneak.berlin/go/pixa/internal/imagerequest"
"sneak.berlin/go/pixa/internal/seal"
)
// TestImageProxyRefusesFitOutsideAboveMaximum requests sizes with fit=outside
@@ -42,11 +43,13 @@ func TestImageProxyRefusesFitOutsideAboveMaximum(t *testing.T) {
s, _, _ := startImageProxy(t, upstream)
generator, err := encurl.NewGenerator(testSigningKey)
keys, err := seal.DeriveKeys(testSigningKey)
if err != nil {
t.Fatalf("encurl.NewGenerator: %v", err)
t.Fatalf("seal.DeriveKeys: %v", err)
}
generator := encurl.NewGenerator(keys.EncryptedURLKey)
tests := []struct {
path string
width, height int
internal/server/source_url_internal_test.go
+5 -2
View File
@@ -16,6 +16,7 @@ import (
"sneak.berlin/go/pixa/internal/encurl"
"sneak.berlin/go/pixa/internal/imagerequest"
"sneak.berlin/go/pixa/internal/imgcache"
"sneak.berlin/go/pixa/internal/seal"
"sneak.berlin/go/pixa/internal/session"
"sneak.berlin/go/pixa/internal/signature"
)
@@ -540,11 +541,13 @@ func signedImageURL(t *testing.T, sourceHost string) string {
func encryptedImageURL(t *testing.T, sourceHost string) string {
t.Helper()
generator, err := encurl.NewGenerator(testSigningKey)
keys, err := seal.DeriveKeys(testSigningKey)
if err != nil {
t.Fatalf("encurl.NewGenerator: %v", err)
t.Fatalf("seal.DeriveKeys: %v", err)
}
generator := encurl.NewGenerator(keys.EncryptedURLKey)
token, err := generator.Generate(&imagerequest.Request{
Source: imagerequest.Source{Host: sourceHost, Path: ipv6SourcePath},
Transform: imagerequest.Transform{Format: imagerequest.FormatPNG},
internal/server/svg_as_avif_internal_test.go
+5 -2
View File
@@ -10,6 +10,7 @@ import (
"sneak.berlin/go/pixa/internal/encurl"
"sneak.berlin/go/pixa/internal/imagerequest"
"sneak.berlin/go/pixa/internal/seal"
)
// svgServedAsAVIF is an SVG whose first bytes pass the first-bytes check for
@@ -34,11 +35,13 @@ func TestImageProxyRefusesSVGServedAsAVIF(t *testing.T) {
s, _, _ := startImageProxy(t, upstream)
generator, err := encurl.NewGenerator(testSigningKey)
keys, err := seal.DeriveKeys(testSigningKey)
if err != nil {
t.Fatalf("encurl.NewGenerator: %v", err)
t.Fatalf("seal.DeriveKeys: %v", err)
}
generator := encurl.NewGenerator(keys.EncryptedURLKey)
encryptedURL := func(format imagerequest.Format) string {
token, err := generator.Generate(&imagerequest.Request{
Source: imagerequest.Source{Host: upstreamHost, Path: "/drawing.avif"},
internal/session/session.go
+9 -28
View File
@@ -22,10 +22,6 @@ import (
const (
CookieName = "pixa_session"
SessionTTL = 30 * 24 * time.Hour // 30 days
// HKDF salts for key derivation
hashKeySalt = "pixa-session-hash-v1"
blockKeySalt = "pixa-session-block-v1"
)
// Errors returned by session operations.
@@ -66,35 +62,23 @@ type Manager struct {
logoutValue string
}
// NewManager creates a session manager with keys derived from the signing key.
// It makes a new random value and keeps it in memory only, so a restart ends
// every session; NewManagerWithDatabase keeps the value in the database.
// NewManager creates a session manager whose session cookies hashKey signs
// and blockKey encrypts. It makes a new random value and keeps it in memory
// only, so a restart ends every session; NewManagerWithDatabase keeps the
// value in the database.
//
// Session cookies always carry the Secure, HttpOnly, and SameSite=Strict
// attributes; this cannot be configured. Browsers treat http://localhost as a
// trustworthy origin and accept Secure cookies there, so local development
// keeps working.
func NewManager(signingKey string) (*Manager, error) {
masterKey := []byte(signingKey)
// Derive separate keys for HMAC (hash) and encryption (block)
hashKey, err := seal.DeriveKey(masterKey, hashKeySalt)
if err != nil {
return nil, err
}
blockKey, err := seal.DeriveKey(masterKey, blockKeySalt)
if err != nil {
return nil, err
}
func NewManager(hashKey, blockKey [seal.KeySize]byte) *Manager {
sc := securecookie.New(hashKey[:], blockKey[:])
sc.MaxAge(int(SessionTTL.Seconds()))
return &Manager{
sc: sc,
logoutValue: rand.Text(),
}, nil
}
}
// NewManagerWithDatabase creates a session manager like NewManager that keeps
@@ -102,14 +86,11 @@ func NewManager(signingKey string) (*Manager, error) {
// NewManager made when db has none, and otherwise starts from the one saved
// there.
func NewManagerWithDatabase(
ctx context.Context, signingKey string, db *sql.DB,
ctx context.Context, hashKey, blockKey [seal.KeySize]byte, db *sql.DB,
) (*Manager, error) {
m, err := NewManager(signingKey)
if err != nil {
return nil, err
}
m := NewManager(hashKey, blockKey)
_, err = db.ExecContext(ctx,
_, err := db.ExecContext(ctx,
"INSERT OR IGNORE INTO logout (id, logout_value) VALUES (1, ?)",
m.logoutValue)
if err != nil {
internal/session/session_cookie_attributes_test.go
+5 -2
View File
@@ -5,6 +5,7 @@ import (
"net/http/httptest"
"testing"
"sneak.berlin/go/pixa/internal/seal"
"sneak.berlin/go/pixa/internal/session"
)
@@ -20,11 +21,13 @@ import (
func TestSessionCookieAttributesAlwaysSecure(t *testing.T) {
t.Parallel()
mgr, err := session.NewManager("test-signing-key-12345")
keys, err := seal.DeriveKeys("test-signing-key-12345")
if err != nil {
t.Fatalf("NewManager() error = %v", err)
t.Fatalf("seal.DeriveKeys() error = %v", err)
}
mgr := session.NewManager(keys.SessionHashKey, keys.SessionBlockKey)
writePaths := []struct {
name string
setCookie func(t *testing.T, w http.ResponseWriter)
internal/session/session_logout_test.go
+15 -4
View File
@@ -8,6 +8,7 @@ import (
"testing"
"sneak.berlin/go/pixa/internal/database"
"sneak.berlin/go/pixa/internal/seal"
"sneak.berlin/go/pixa/internal/session"
)
@@ -80,8 +81,13 @@ func TestLogout_EndsEverySessionMadeBeforeIt(t *testing.T) {
db := newTestDatabase(t)
keys, err := seal.DeriveKeys(logoutTestSigningKey)
if err != nil {
t.Fatalf("seal.DeriveKeys() error = %v", err)
}
mgr, err := session.NewManagerWithDatabase(
t.Context(), logoutTestSigningKey, db)
t.Context(), keys.SessionHashKey, keys.SessionBlockKey, db)
if err != nil {
t.Fatalf("NewManagerWithDatabase() error = %v", err)
}
@@ -109,7 +115,7 @@ func TestLogout_EndsEverySessionMadeBeforeIt(t *testing.T) {
}
restarted, err := session.NewManagerWithDatabase(
t.Context(), logoutTestSigningKey, db)
t.Context(), keys.SessionHashKey, keys.SessionBlockKey, db)
if err != nil {
t.Fatalf("NewManagerWithDatabase() after restart error = %v", err)
}
@@ -129,8 +135,13 @@ func TestLogout_EndsEverySessionMadeBeforeIt(t *testing.T) {
func TestLogout_WithoutSession_EndsNoSession(t *testing.T) {
t.Parallel()
mgr, err := session.NewManagerWithDatabase(
t.Context(), logoutTestSigningKey, newTestDatabase(t))
keys, err := seal.DeriveKeys(logoutTestSigningKey)
if err != nil {
t.Fatalf("seal.DeriveKeys() error = %v", err)
}
mgr, err := session.NewManagerWithDatabase(t.Context(),
keys.SessionHashKey, keys.SessionBlockKey, newTestDatabase(t))
if err != nil {
t.Fatalf("NewManagerWithDatabase() error = %v", err)
}
internal/session/session_test.go
+19 -9
View File
@@ -7,17 +7,20 @@ import (
"testing"
"time"
"sneak.berlin/go/pixa/internal/seal"
"sneak.berlin/go/pixa/internal/session"
)
func TestManager_CreateAndValidate(t *testing.T) {
t.Parallel()
mgr, err := session.NewManager("test-signing-key-12345")
keys, err := seal.DeriveKeys("test-signing-key-12345")
if err != nil {
t.Fatalf("NewManager() error = %v", err)
t.Fatalf("seal.DeriveKeys() error = %v", err)
}
mgr := session.NewManager(keys.SessionHashKey, keys.SessionBlockKey)
// Create a session
w := httptest.NewRecorder()
@@ -69,7 +72,8 @@ func TestManager_CreateAndValidate(t *testing.T) {
func TestManager_ValidateSession_NoCookie(t *testing.T) {
t.Parallel()
mgr, _ := session.NewManager("test-signing-key-12345")
keys, _ := seal.DeriveKeys("test-signing-key-12345")
mgr := session.NewManager(keys.SessionHashKey, keys.SessionBlockKey)
req := httptest.NewRequestWithContext(t.Context(), http.MethodGet, "/", nil)
@@ -86,7 +90,8 @@ func TestManager_ValidateSession_NoCookie(t *testing.T) {
func TestManager_ValidateSession_TamperedCookie(t *testing.T) {
t.Parallel()
mgr, _ := session.NewManager("test-signing-key-12345")
keys, _ := seal.DeriveKeys("test-signing-key-12345")
mgr := session.NewManager(keys.SessionHashKey, keys.SessionBlockKey)
req := httptest.NewRequestWithContext(t.Context(), http.MethodGet, "/", nil)
req.AddCookie(&http.Cookie{
@@ -110,8 +115,10 @@ func TestManager_ValidateSession_TamperedCookie(t *testing.T) {
func TestManager_ValidateSession_WrongKey(t *testing.T) {
t.Parallel()
mgr1, _ := session.NewManager("signing-key-1")
mgr2, _ := session.NewManager("signing-key-2")
keys1, _ := seal.DeriveKeys("signing-key-1")
keys2, _ := seal.DeriveKeys("signing-key-2")
mgr1 := session.NewManager(keys1.SessionHashKey, keys1.SessionBlockKey)
mgr2 := session.NewManager(keys2.SessionHashKey, keys2.SessionBlockKey)
// Create session with mgr1
w := httptest.NewRecorder()
@@ -142,7 +149,8 @@ func TestManager_ValidateSession_WrongKey(t *testing.T) {
func TestManager_ClearSession(t *testing.T) {
t.Parallel()
mgr, _ := session.NewManager("test-signing-key-12345")
keys, _ := seal.DeriveKeys("test-signing-key-12345")
mgr := session.NewManager(keys.SessionHashKey, keys.SessionBlockKey)
w := httptest.NewRecorder()
mgr.ClearSession(w)
@@ -172,7 +180,8 @@ func TestManager_ClearSession(t *testing.T) {
func TestManager_IsAuthenticated(t *testing.T) {
t.Parallel()
mgr, _ := session.NewManager("test-signing-key-12345")
keys, _ := seal.DeriveKeys("test-signing-key-12345")
mgr := session.NewManager(keys.SessionHashKey, keys.SessionBlockKey)
// No session - should return false
req := httptest.NewRequestWithContext(t.Context(), http.MethodGet, "/", nil)
@@ -208,7 +217,8 @@ func TestManager_IsAuthenticated(t *testing.T) {
func TestManager_CookieAttributes(t *testing.T) {
t.Parallel()
mgr, _ := session.NewManager("test-key")
keys, _ := seal.DeriveKeys("test-key")
mgr := session.NewManager(keys.SessionHashKey, keys.SessionBlockKey)
w := httptest.NewRecorder()
_ = mgr.CreateSession(w)