cmd/mesh-controller/buscertificate.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"crypto/rand"
 	"crypto/rsa"
 	"crypto/x509"
@@ -12,7 +13,10 @@ import (
 	"net"
 	"os"
 	"path/filepath"
+	"strings"
 	"time"
+
+	"github.com/novox/mesh-controller/internal/broker"
 )
 
 // The bus's own certificate, made by the mesh rather than borrowed from an image.
@@ -169,3 +173,86 @@ func writeBusCertificate(crt, key string) error {
 		busCertificateNames, template.NotAfter.Format(time.RFC3339), crt, key)
 	return nil
 }
+
+// busAccounts writes the mesh's composed user list to a file.
+//
+// **For genesis, where no declaration can deliver it** (novox/hq 04-ISSUES/146). Everywhere else
+// the list reaches the machine running the bus as a resource of the module that holds it — which
+// requires that machine to be an enrolled node, and at genesis it is not: the first node cannot
+// enrol because the account it would enrol with cannot be composed onto a bus it has no declaration
+// for. The installer breaks that circle by placing the file itself, once, and the module takes the
+// file over from its first push.
+//
+// The same composition, not a second one: this asks the store for the same records and renders them
+// with the same composer the declaration uses. A genesis that hand-wrote an account would be a
+// second statement of who may say what, able to disagree with the first.
+//
+// **It writes to standard output unless told a file**, and that is the point: the control plane
+// composes and says what it composed, and whoever is raising the machine puts it where that
+// machine's bus reads it. A control plane that wrote into the bus's own directory would have to
+// know where that is and how to make the server re-read it — which is the module's knowledge, and
+// the module is what takes this over on the first push.
+//
+//	broker accounts > /var/lib/mesh-bus-conf/accounts.conf
+func busAccounts(ctx context.Context, args []string) error {
+	into := ""
+	for i := 0; i < len(args); i++ {
+		switch args[i] {
+		case "--into":
+			if i+1 >= len(args) {
+				return errors.New("--into needs a file")
+			}
+			into = args[i+1]
+			i++
+		default:
+			return fmt.Errorf("broker accounts --into <file>: %q", args[i])
+		}
+	}
+
+	open, err := openStores(ctx)
+	if err != nil {
+		return err
+	}
+	defer open.Close()
+
+	records, err := open.inventory.BusRecords(ctx)
+	if err != nil {
+		return err
+	}
+	users, err := broker.Users(records)
+	if err != nil {
+		return err
+	}
+	kept, err := open.inventory.BusUsers(ctx)
+	if err != nil {
+		return err
+	}
+	hashes := make(map[string]string, len(kept))
+	for name, u := range kept {
+		hashes[name] = u.PasswordHash
+	}
+	filled, missing := broker.WithPasswords(users, hashes)
+	if len(missing) > 0 {
+		// To standard error, always: the composed file may be going to standard output, and a
+		// remark in the middle of it is a configuration the server refuses to parse.
+		fmt.Fprintf(os.Stderr, "leaving out %d user(s) the mesh has minted no credential for: %s\n",
+			len(missing), strings.Join(missing, ", "))
+	}
+	if len(filled) == 0 {
+		return errors.New("not one user has a credential, so this list would refuse every " +
+			"connection in the mesh")
+	}
+	accounts, err := broker.ComposeAccounts(filled)
+	if err != nil {
+		return err
+	}
+	if into == "" {
+		fmt.Print(accounts)
+		return nil
+	}
+	if err := os.WriteFile(into, []byte(accounts), 0o600); err != nil {
+		return err
+	}
+	fmt.Printf("wrote %d user(s) to %s\n", len(filled), into)
+	return nil
+}

cmd/mesh-controller/main.go

@@ -88,7 +88,7 @@ func run() error {
 	case "identity":
 		return identityCommand(ctx, args[1:])
 	case "broker":
-		return brokerCommand(args[1:])
+		return brokerCommand(ctx, args[1:])
 	case "serve":
 		return serve(ctx)
 	case "upgrade":

cmd/mesh-controller/nodes.go

@@ -363,12 +363,15 @@ func identityCommand(ctx context.Context, args []string) error {
 	return nil
 }
 
-func brokerCommand(args []string) error {
+func brokerCommand(ctx context.Context, args []string) error {
 	if len(args) > 0 && args[0] == "certificate" {
 		return busCertificate(args[1:])
 	}
+	if len(args) > 0 && args[0] == "accounts" {
+		return busAccounts(ctx, args[1:])
+	}
 	if len(args) == 0 || args[0] != "show" {
-		return errors.New("broker show | broker certificate [--check] --into <directory>")
+		return errors.New("broker show | broker certificate [--check] --into <directory> | broker accounts --into <file>")
 	}
 	known, err := broker.FromEnvironment()
 	if errors.Is(err, broker.ErrNotConfigured) {

internal/broker/genesis_template_test.go

@@ -62,6 +62,22 @@ func TestTheInstallersFirstUserListIsWhatTheControllerWouldCompose(t *testing.T)
 
 // theCarriedAccounts is the accounts file the installer's template writes at genesis.
 func theCarriedAccounts(t *testing.T) string {
+	t.Helper()
+	for _, r := range theTemplate(t) {
+		if r["id"] == "bus-accounts" {
+			content, _ := r["content"].(string)
+			if content == "" {
+				t.Fatal("the template's accounts file is empty, so the bus would refuse every connection")
+			}
+			return content
+		}
+	}
+	t.Fatal("the template carries no accounts file, so a mesh raised from it has a bus nobody may use")
+	return ""
+}
+
+// theTemplate is the installer's bundle, as resources.
+func theTemplate(t *testing.T) []map[string]any {
 	t.Helper()
 	path := filepath.Join("..", "..", "..", "mesh-host", "examples", "foundation-first-node-nats.lock")
 	raw, err := os.ReadFile(path)
@@ -81,17 +97,7 @@ func theCarriedAccounts(t *testing.T) string {
 	if err := json.Unmarshal([]byte(strings.Join(lines, "\n")), &bundle); err != nil {
 		t.Fatalf("the template is not readable: %v", err)
 	}
-	for _, r := range bundle.Resources {
-		if r["id"] == "bus-accounts" {
-			content, _ := r["content"].(string)
-			if content == "" {
-				t.Fatal("the template's accounts file is empty, so the bus would refuse every connection")
-			}
-			return content
-		}
-	}
-	t.Fatal("the template carries no accounts file, so a mesh raised from it has a bus nobody may use")
-	return ""
+	return bundle.Resources
 }
 
 // subjectsIn reads one allow-list out of a composed accounts file.

internal/inventory/busrecords_test.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/novox/mesh-controller/internal/broker"
 	"github.com/novox/mesh-controller/internal/catalogue"
+	"golang.org/x/crypto/bcrypt"
 )
 
 // Reading the bus's user list out of the mesh's records, against a real store.
@@ -164,3 +165,63 @@ func granted(all []string, one string) bool {
 	}
 	return false
 }
+
+// **A token is an account on the bus, or it is a string nothing accepts** (novox/hq 04-ISSUES/146).
+//
+// The composed list names an enrolment user for every machine with a live token, and nothing minted
+// a credential for it — so the composer left it out as a user with no password, and every enrolment
+// since the mesh moved to this bus was refused by the server before the mesh heard of it. Nothing
+// caught it because nothing had enrolled since.
+//
+// The password cannot be minted, because it is the token's own secret: the machine will present
+// exactly that string. So this checks the two halves that make the account usable — that a row
+// exists under the name the composer asks for, and that the secret handed out is what that row
+// accepts.
+func TestIssuingATokenRecordsTheAccountItIsThePasswordOf(t *testing.T) {
+	inv, ctx := aMeshWith(t)
+	if _, err := inv.AddNode(ctx, "joiner"); err != nil {
+		t.Fatal(err)
+	}
+	issued, err := inv.IssueToken(ctx, "joiner", time.Hour)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	name := broker.Principal{Kind: broker.KindEnrolment, Node: "joiner"}.Username()
+	users, err := inv.BusUsers(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	user, has := users[name]
+	if !has {
+		t.Fatalf("no bus account for %q; the composer would leave the enrolment out and the "+
+			"machine would be refused before the mesh heard of it: %v", name, users)
+	}
+	if user.Kind != BusEnrolment || user.Node != "joiner" {
+		t.Errorf("the account is %+v, not this node's enrolment", user)
+	}
+	if err := bcrypt.CompareHashAndPassword([]byte(user.PasswordHash), []byte(issued.Secret)); err != nil {
+		t.Error("the account does not accept the secret the token carries, so presenting the " +
+			"token would be refused by the server")
+	}
+
+	// And the composition contains it, which is the thing the server reads.
+	records, err := inv.BusRecords(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	derived, err := broker.Users(records)
+	if err != nil {
+		t.Fatal(err)
+	}
+	hashes := map[string]string{}
+	for n, u := range users {
+		hashes[n] = u.PasswordHash
+	}
+	_, missing := broker.WithPasswords(derived, hashes)
+	for _, m := range missing {
+		if m == name {
+			t.Fatal("the enrolment user is composed without a password, which is a user nobody can be")
+		}
+	}
+}

internal/inventory/bususers.go

@@ -51,6 +51,40 @@ const (
 // reply, into a module's sealed environment — and the mesh keeps only the hash, so a credential is
 // never recoverable from the store. A caller that loses it must mint again, which is a rotation and
 // is meant to feel like one.
+// RecordBusPassword records a hash for a password the caller already holds.
+//
+// **For the one credential the mesh does not choose**: an enrolment token's secret is the password
+// of the user that presents it (novox/hq ADR 0004, design 25 §6), so the token cannot be given a
+// minted password — it already has one, and the machine will connect with exactly that string.
+// Everything else goes through Mint, which chooses and returns the plaintext once.
+func (i *Inventory) RecordBusPassword(ctx context.Context, u BusUser, password string) error {
+	if u.Username == "" || u.Kind == "" {
+		return errors.New("a bus user needs a username and a kind")
+	}
+	if password == "" {
+		return errors.New("a bus user needs a password")
+	}
+	hash, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
+	if err != nil {
+		return fmt.Errorf("cannot hash a bus password: %w", err)
+	}
+	return i.writeBusUser(ctx, u, string(hash))
+}
+
+// writeBusUser is the row, whoever chose the password.
+func (i *Inventory) writeBusUser(ctx context.Context, u BusUser, hash string) error {
+	if _, err := i.store.Pool().Exec(ctx,
+		`insert into bus_user (username, kind, node, module, password_hash)
+		 values ($1, $2, $3, $4, $5)
+		 on conflict (username) do update
+		   set kind = excluded.kind, node = excluded.node, module = excluded.module,
+		       password_hash = excluded.password_hash, minted_at = now()`,
+		u.Username, u.Kind, u.Node, u.Module, hash); err != nil {
+		return fmt.Errorf("cannot record the bus user %s: %w", u.Username, err)
+	}
+	return nil
+}
+
 func (i *Inventory) MintBusPassword(ctx context.Context, u BusUser) (string, error) {
 	if u.Username == "" || u.Kind == "" {
 		return "", errors.New("a bus user needs a username and a kind")
@@ -69,14 +103,8 @@ func (i *Inventory) MintBusPassword(ctx context.Context, u BusUser) (string, err
 		return "", fmt.Errorf("cannot hash a bus password: %w", err)
 	}
 
-	if _, err := i.store.Pool().Exec(ctx,
-		`insert into bus_user (username, kind, node, module, password_hash)
-		 values ($1, $2, $3, $4, $5)
-		 on conflict (username) do update
-		   set kind = excluded.kind, node = excluded.node, module = excluded.module,
-		       password_hash = excluded.password_hash, minted_at = now()`,
-		u.Username, u.Kind, u.Node, u.Module, string(hash)); err != nil {
-		return "", fmt.Errorf("cannot record the bus user %s: %w", u.Username, err)
+	if err := i.writeBusUser(ctx, u, string(hash)); err != nil {
+		return "", err
 	}
 	return password, nil
 }

internal/inventory/nodes.go

@@ -14,6 +14,7 @@ import (
 	"time"
 
 	"github.com/jackc/pgx/v5"
+	"github.com/novox/mesh-controller/internal/broker"
 	"github.com/novox/mesh-controller/internal/store"
 )
 
@@ -263,6 +264,29 @@ func (i *Inventory) IssueToken(ctx context.Context, nodeName string, validFor ti
 		return Issued{}, err
 	}
 
+	// **And the account that secret is the password of** (novox/hq 04-ISSUES/146). The composed
+	// user list names an enrolment user for every node with a live token, and nothing minted a
+	// credential for it — so the composer left it out as a user with no password and every
+	// enrolment was refused by the server before the mesh heard of it.
+	//
+	// Recorded rather than minted: the token's secret IS the password, which is what lets a
+	// machine's first connection be authenticated by the thing it is enrolling with. It cannot be
+	// chosen here, because it has already been handed to whoever will present it.
+	//
+	// Outside the transaction on purpose. The token is what the mesh promised; a credential that
+	// the next composition rewrites anyway is not worth failing an issue over, and a token with no
+	// account is recoverable by issuing another, while an account with no token is a user nobody
+	// can be.
+	if err := i.RecordBusPassword(ctx, BusUser{
+		Username: broker.Principal{Kind: broker.KindEnrolment, Node: node.Name}.Username(),
+		Kind:     BusEnrolment,
+		Node:     node.Name,
+	}, secret); err != nil {
+		return Issued{}, fmt.Errorf(
+			"the token for %s was issued and the bus account it is the password of was not "+
+				"recorded, so this token cannot connect: %w", node.Name, err)
+	}
+
 	return Issued{Node: node, Secret: secret, Expires: expires}, nil
 }