Vault: name a hash record's secret in a field called of, so the runtime accepts it

The runtime refuses a state field whose name ends in secret, so no bus-account hash could be written on novox. The test state now applies the same check.

Issue: 1945

modules/mesh-vault/cmd/mesh-vault/.gitignore

@@ -0,0 +1 @@
+/mesh-vault

modules/mesh-vault/cmd/mesh-vault/accounts.go

@@ -42,8 +42,9 @@ type AccountHash struct {
 	User string `json:"user"`
 	// Hash is the bcrypt hash of the account's password, at the composer's cost.
 	Hash string `json:"hash"`
-	// Secret, Generation and Fingerprint are the vault's own secret the hash is of: absent for an adopted one.
-	Secret      string    `json:"secret,omitempty"`
+	// Of, Generation and Fingerprint name the vault's own secret the hash is of: absent for an adopted one. The field
+	// is not called "secret": the runtime refuses a state field whose name says it is a credential (ADR 0201).
+	Of          string    `json:"of,omitempty"`
 	Generation  int       `json:"generation,omitempty"`
 	Fingerprint string    `json:"fingerprint,omitempty"`
 	At          time.Time `json:"at"`
@@ -149,7 +150,7 @@ func accountOf(secret, value string) (user, password string, err error) {
 
 // Hashed is what one hashing did: the key written or found, never the hash.
 type Hashed struct {
-	Secret      string    `json:"secret"`
+	Of          string    `json:"of"`
 	User        string    `json:"user"`
 	Generation  int       `json:"generation"`
 	Fingerprint string    `json:"fingerprint"`
@@ -178,13 +179,13 @@ func (v *Vault) HashAccount(secret string, force bool) (Hashed, error) {
 		return Hashed{}, err
 	}
 	fp := Fingerprint(value)
-	h := Hashed{Secret: secret, User: user, Generation: rec.Generation, Fingerprint: fp}
+	h := Hashed{Of: secret, User: user, Generation: rec.Generation, Fingerprint: fp}
 	was, err := v.Accounts.Get(user)
 	if err != nil {
 		v.hashes.owe(secret, "its key could not be read: "+err.Error())
 		return Hashed{}, fmt.Errorf("%s %s could not be read: %w", BusAccountsState, user, err)
 	}
-	if !force && was != nil && !was.Adopted && was.Secret == secret && was.Generation == rec.Generation && was.Fingerprint == fp {
+	if !force && was != nil && !was.Adopted && was.Of == secret && was.Generation == rec.Generation && was.Fingerprint == fp {
 		v.hashes.paid(secret)
 		h.At = was.At
 		return h, nil
@@ -194,7 +195,7 @@ func (v *Vault) HashAccount(secret string, force bool) (Hashed, error) {
 		return Hashed{}, err
 	}
 	h.At = v.Now().UTC()
-	if err := v.Accounts.Put(AccountHash{User: user, Hash: string(hash), Secret: secret, Generation: rec.Generation,
+	if err := v.Accounts.Put(AccountHash{User: user, Hash: string(hash), Of: secret, Generation: rec.Generation,
 		Fingerprint: fp, At: h.At}); err != nil {
 		v.hashes.owe(secret, "its key could not be written: "+err.Error())
 		return Hashed{}, fmt.Errorf("the hash of %s (generation %d) could not be written to %s %s, tried again at the "+
@@ -203,7 +204,7 @@ func (v *Vault) HashAccount(secret string, force bool) (Hashed, error) {
 	v.hashes.paid(secret)
 	h.Written = true
 	if v.Emit != nil {
-		if err := v.Emit(AccountHashedEvent, map[string]any{"user": user, "secret": secret, "generation": rec.Generation,
+		if err := v.Emit(AccountHashedEvent, map[string]any{"user": user, "of": secret, "generation": rec.Generation,
 			"fingerprint": fp, "at": h.At.Format(time.RFC3339Nano)}); err != nil {
 			v.log("the hash of %s is written, but %s could not be said: %v", secret, AccountHashedEvent, err)
 		}

modules/mesh-vault/cmd/mesh-vault/credential_field_test.go

@@ -0,0 +1,67 @@
+package main
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+)
+
+// credentialEndings and credentialField mirror the runtime's refusal of a state or log value with a field whose name says
+// it is a credential (mesh-tools node-tools/internal/bus/state.go, credentialField, ADR 0201): the runtime's check is
+// unexported and in another repository, so this is a copy and must follow it. A fake state that skips it let a
+// field named "secret" pass every test and be refused on novox (issue 1945).
+var credentialEndings = []string{"password", "passwd", "secret", "token", "credential", "credentials",
+	"authorization", "apikey", "privatekey", "accesskey", "cookie"}
+
+func credentialField(value []byte) string {
+	var v any
+	if json.Unmarshal(value, &v) != nil {
+		return ""
+	}
+	var walk func(any) string
+	walk = func(v any) string {
+		switch t := v.(type) {
+		case map[string]any:
+			for k, x := range t {
+				norm := strings.NewReplacer("-", "", "_", "", " ", "").Replace(strings.ToLower(k))
+				for _, end := range credentialEndings {
+					if strings.HasSuffix(norm, end) {
+						return k
+					}
+				}
+				if f := walk(x); f != "" {
+					return f
+				}
+			}
+		case []any:
+			for _, x := range t {
+				if f := walk(x); f != "" {
+					return f
+				}
+			}
+		}
+		return ""
+	}
+	return walk(v)
+}
+
+// The vault's bus-accounts records pass the runtime's credential-field check; a record with a "secret" field does not.
+func TestStateRecordsPassTheRuntimesCredentialFieldCheck(t *testing.T) {
+	for _, c := range []struct {
+		name  string
+		value any
+		field string
+	}{
+		{"a hash record of the vault's own secret", AccountHash{User: "ace.mesh-build-go", Hash: "$2a$10$h", Of: "own/ace/mesh-build-go/broker", Generation: 1, Fingerprint: "ab12"}, ""},
+		{"an adopted hash record", AccountHash{User: "ace.x", Hash: "$2a$10$h", Adopted: true}, ""},
+		{"a record with a secret field is refused", map[string]any{"user": "u", "secret": "own/x"}, "secret"},
+	} {
+		raw, err := json.Marshal(c.value)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if got := credentialField(raw); got != c.field {
+			t.Errorf("%s: credential field %q, want %q (%s)", c.name, got, c.field, raw)
+		}
+	}
+}

modules/mesh-vault/cmd/mesh-vault/issued_account_test.go

@@ -1,7 +1,9 @@
 package main
 
 import (
+	"encoding/json"
 	"errors"
+	"fmt"
 	"strings"
 	"sync"
 	"testing"
@@ -36,6 +38,11 @@ func (f *fakeAccounts) Put(a AccountHash) error {
 	if f.keys == nil {
 		f.keys = map[string]AccountHash{}
 	}
+	// What the runtime does to every state value (credential_field_test.go): the vault's own record is checked as written.
+	raw, _ := json.Marshal(a)
+	if field := credentialField(raw); field != "" {
+		return fmt.Errorf("%s carries a field %q, which names a credential: no secret is kept in state", a.User, field)
+	}
 	f.keys[a.User] = a
 	f.puts++
 	return nil

modules/mesh-vault/cmd/mesh-vault/tools.go

@@ -761,8 +761,8 @@ func hashedRow(v *Vault, r Record, fp string, row map[string]any) {
 		row["hashed"], row["hashWhy"] = false, "no key"
 	case h.Adopted:
 		row["hashed"], row["hashedAt"], row["hashWhy"] = false, h.At, "the key is adopted from the loaded list, not of this value"
-	case h.Secret != r.Name || h.Generation != r.Generation || h.Fingerprint != fp:
-		row["hashed"], row["hashedAt"], row["hashWhy"] = false, h.At, fmt.Sprintf("the key is of %s generation %d", h.Secret, h.Generation)
+	case h.Of != r.Name || h.Generation != r.Generation || h.Fingerprint != fp:
+		row["hashed"], row["hashedAt"], row["hashWhy"] = false, h.At, fmt.Sprintf("the key is of %s generation %d", h.Of, h.Generation)
 	default:
 		row["hashed"], row["hashedAt"] = true, h.At
 	}