1 files changed, 31 insertions, 20 deletions
diff --git a/internal/game/core_login_account.go b/internal/game/core_login_account.go
index 371c287..f6e5631 100644
--- a/internal/game/core_login_account.go
+++ b/internal/game/core_login_account.go
@@ -19,6 +19,7 @@ func (g *Game) handleAccountName(sess *net.Session, input string) {
 	actualName, err := g.AccountStore.FindAccount(name)
 	if err == nil {
 		sess.Account = &player.Account{Name: actualName}
+		sess.SetAuthName(actualName)
 		sess.State = net.StatePassword
 		sess.SetEcho(false)
 		sess.Write("Password: ")
@@ -29,6 +30,7 @@ func (g *Game) handleAccountName(sess *net.Session, input string) {
 			return
 		}
 		sess.Account = &player.Account{Name: name}
+		sess.SetAuthName(name)
 		sess.State = net.StateNewAccountPass
 		sess.SetEcho(false)
 		sess.WriteLine("\r\nOh, a new visitor to this rock!")
@@ -99,17 +101,9 @@ type passwordAuth struct {
 // The production entry point; handlePassword stays for direct HandleSession
 // callers (tests) but hashes on the owner there.
 func (g *Game) handlePasswordOffOwner(sess *net.Session, input string) {
-	if sess.Account == nil {
-		// Defensive: password prompts only follow an account-name step.
-		g.RunOnOwner(func() {
-			if g.isShuttingDown() {
-				return
-			}
-			g.handlePassword(sess, input)
-		})
-		return
-	}
 	if input == "" || len(input) > 128 {
+		// These checks touch no session state, so they are race-free off
+		// the owner; they also keep Argon2id off absurd inputs.
 		tooshort := input == ""
 		g.RunOnOwner(func() {
 			if g.isShuttingDown() {
@@ -127,8 +121,24 @@ func (g *Game) handlePasswordOffOwner(sess *net.Session, input string) {
 		})
 		return
 	}
+	// The account name comes from the race-free authName snapshot (set by
+	// the owner when the password prompt was offered), NOT from
+	// sess.Account: the owner goroutine can replace Account at any moment
+	// (account republish after a rename/purge), and reading a plain field
+	// the owner concurrently writes is a data race.
+	name := sess.AuthName()
+	if name == "" {
+		// Defensive: password prompts only follow an account-name step.
+		g.RunOnOwner(func() {
+			if g.isShuttingDown() {
+				return
+			}
+			g.handlePassword(sess, input)
+		})
+		return
+	}
 	auth := passwordAuth{}
-	acc, err := g.AccountStore.LoadAccount(sess.Account.Name)
+	acc, err := g.AccountStore.LoadAccount(name)
 	switch {
 	case err != nil:
 		auth.loadErr = true
@@ -251,20 +261,21 @@ func (g *Game) handleNewAccount(sess *net.Session, input string) {
 // for the existence re-check and save.
 func (g *Game) handleNewAccountOffOwner(sess *net.Session, input string) {
 	input = strings.TrimSpace(input)
-	if input == "" || input != sess.PendingPass {
-		g.RunOnOwner(func() {
-			if g.isShuttingDown() {
-				return
-			}
-			g.handleNewAccount(sess, input)
-		})
-		return
-	}
+	// Hash unconditionally on the connection goroutine (Argon2id is
+	// expensive); the owner task below re-checks the empty/mismatch cases
+	// against owner-owned session state, so PendingPass is never read off
+	// the owner. A wasted hash only happens on the rare mismatched-confirm
+	// path, where handleNewAccount's own validation rejects it without a
+	// second hash.
 	hash, hashErr := player.HashPassword(input)
 	g.RunOnOwner(func() {
 		if g.isShuttingDown() {
 			return
 		}
+		if input == "" || input != sess.PendingPass {
+			g.handleNewAccount(sess, input)
+			return
+		}
 		g.applyNewAccount(sess, hash, hashErr)
 	})
 }