ipn/ipnlocal: account for currentUserID when iterating over knownProfiles

We were not checking the currentUserID in all code paths that looped over
knownProfiles. This only impacted multi-user Windows setups.

Updates #713

Signed-off-by: Maisem Ali <maisem@tailscale.com>

ipn/ipnlocal/profiles.go

@@ -51,6 +51,7 @@ func (pm *profileManager) SetCurrentUser(uid string) error {
 	if pm.currentUserID == uid {
 		return nil
 	}
+	pm.currentUserID = uid
 	cpk := ipn.CurrentProfileKey(uid)
 	if b, err := pm.store.ReadState(cpk); err == nil {
 		pk := ipn.StateKey(string(b))
@@ -66,34 +67,36 @@ func (pm *profileManager) SetCurrentUser(uid string) error {
 	} else {
 		return err
 	}
-	pm.currentUserID = uid
 	return nil
 }
 
-func (pm *profileManager) findProfilesByNodeID(nodeID tailcfg.StableNodeID) []*ipn.LoginProfile {
-	if nodeID.IsZero() {
-		return nil
-	}
-	var out []*ipn.LoginProfile
+// matchingProfiles returns all profiles that match the given predicate and
+// belong to the currentUserID.
+func (pm *profileManager) matchingProfiles(f func(*ipn.LoginProfile) bool) (out []*ipn.LoginProfile) {
 	for _, p := range pm.knownProfiles {
-		if p.NodeID == nodeID {
+		if p.LocalUserID == pm.currentUserID && f(p) {
 			out = append(out, p)
 		}
 	}
 	return out
 }
 
+func (pm *profileManager) findProfilesByNodeID(nodeID tailcfg.StableNodeID) []*ipn.LoginProfile {
+	if nodeID.IsZero() {
+		return nil
+	}
+	return pm.matchingProfiles(func(p *ipn.LoginProfile) bool {
+		return p.NodeID == nodeID
+	})
+}
+
 func (pm *profileManager) findProfilesByUserID(userID tailcfg.UserID) []*ipn.LoginProfile {
 	if userID.IsZero() {
 		return nil
 	}
-	var out []*ipn.LoginProfile
-	for _, p := range pm.knownProfiles {
-		if p.UserProfile.ID == userID {
-			out = append(out, p)
-		}
-	}
-	return out
+	return pm.matchingProfiles(func(p *ipn.LoginProfile) bool {
+		return p.UserProfile.ID == userID
+	})
 }
 
 // ProfileIDForName returns the profile ID for the profile with the
@@ -107,21 +110,29 @@ func (pm *profileManager) ProfileIDForName(name string) ipn.ProfileID {
 }
 
 func (pm *profileManager) findProfileByName(name string) *ipn.LoginProfile {
-	for _, p := range pm.knownProfiles {
-		if p.Name == name {
-			return p
+	out := pm.matchingProfiles(func(p *ipn.LoginProfile) bool {
+		return p.Name == name
+	})
+	if len(out) == 0 {
+		return nil
 	}
+	if len(out) > 1 {
+		pm.logf("[unxpected] multiple profiles with the same name")
 	}
-	return nil
+	return out[0]
 }
 
 func (pm *profileManager) findProfileByKey(key ipn.StateKey) *ipn.LoginProfile {
-	for _, p := range pm.knownProfiles {
-		if p.Key == key {
-			return p
+	out := pm.matchingProfiles(func(p *ipn.LoginProfile) bool {
+		return p.Key == key
+	})
+	if len(out) == 0 {
+		return nil
 	}
+	if len(out) > 1 {
+		pm.logf("[unxpected] multiple profiles with the same key")
 	}
-	return nil
+	return out[0]
 }
 
 func (pm *profileManager) setUnattendedModeAsConfigured() error {
@@ -244,16 +255,15 @@ func (pm *profileManager) writePrefsToStore(key ipn.StateKey, prefs ipn.PrefsVie
 
 // Profiles returns the list of known profiles.
 func (pm *profileManager) Profiles() []ipn.LoginProfile {
-	var profiles []ipn.LoginProfile
-	for _, p := range pm.knownProfiles {
-		if p.LocalUserID == pm.currentUserID {
-			profiles = append(profiles, *p)
-		}
-	}
-	slices.SortFunc(profiles, func(a, b ipn.LoginProfile) bool {
+	profiles := pm.matchingProfiles(func(*ipn.LoginProfile) bool { return true })
+	slices.SortFunc(profiles, func(a, b *ipn.LoginProfile) bool {
 		return a.Name < b.Name
 	})
-	return profiles
+	out := make([]ipn.LoginProfile, 0, len(profiles))
+	for _, p := range profiles {
+		out = append(out, *p)
+	}
+	return out
 }
 
 // SwitchProfile switches to the profile with the given id.
@@ -431,6 +441,7 @@ func readKnownProfiles(store ipn.StateStore) (map[ipn.ProfileID]*ipn.LoginProfil
 }
 
 func newProfileManagerWithGOOS(store ipn.StateStore, logf logger.Logf, stateKey ipn.StateKey, goos string) (*profileManager, error) {
+	logf = logger.WithPrefix(logf, "pm: ")
 	if stateKey == "" {
 		var err error
 		stateKey, err = readAutoStartKey(store, goos)

ipn/ipnlocal/profiles_test.go

@@ -16,6 +16,76 @@ import (
 	"tailscale.com/types/persist"
 )
 
+func TestProfileList(t *testing.T) {
+	store := new(mem.Store)
+
+	pm, err := newProfileManagerWithGOOS(store, logger.Discard, "", "linux")
+	if err != nil {
+		t.Fatal(err)
+	}
+	id := 0
+	newProfile := func(t *testing.T, loginName string) ipn.PrefsView {
+		id++
+		t.Helper()
+		pm.NewProfile()
+		p := pm.CurrentPrefs().AsStruct()
+		p.Persist = &persist.Persist{
+			NodeID:         tailcfg.StableNodeID(fmt.Sprint(id)),
+			LoginName:      loginName,
+			PrivateNodeKey: key.NewNode(),
+			UserProfile: tailcfg.UserProfile{
+				ID:        tailcfg.UserID(id),
+				LoginName: loginName,
+			},
+		}
+		if err := pm.SetPrefs(p.View()); err != nil {
+			t.Fatal(err)
+		}
+		return p.View()
+	}
+	checkProfiles := func(t *testing.T, want ...string) {
+		t.Helper()
+		got := pm.Profiles()
+		if len(got) != len(want) {
+			t.Fatalf("got %d profiles, want %d", len(got), len(want))
+		}
+		for i, w := range want {
+			if got[i].Name != w {
+				t.Errorf("got profile %d name %q, want %q", i, got[i].Name, w)
+			}
+		}
+	}
+
+	pm.SetCurrentUser("user1")
+	newProfile(t, "alice")
+	newProfile(t, "bob")
+	checkProfiles(t, "alice", "bob")
+
+	pm.SetCurrentUser("user2")
+	checkProfiles(t)
+	newProfile(t, "carol")
+	carol := pm.currentProfile
+	checkProfiles(t, "carol")
+
+	pm.SetCurrentUser("user1")
+	checkProfiles(t, "alice", "bob")
+	if lp := pm.findProfileByKey(carol.Key); lp != nil {
+		t.Fatalf("found profile for user2 in user1's profile list")
+	}
+	if lp := pm.findProfileByName(carol.Name); lp != nil {
+		t.Fatalf("found profile for user2 in user1's profile list")
+	}
+	if lp := pm.findProfilesByNodeID(carol.NodeID); lp != nil {
+		t.Fatalf("found profile for user2 in user1's profile list")
+	}
+	if lp := pm.findProfilesByUserID(carol.UserProfile.ID); lp != nil {
+		t.Fatalf("found profile for user2 in user1's profile list")
+	}
+
+	pm.SetCurrentUser("user2")
+	checkProfiles(t, "carol")
+}
+
 // TestProfileManagement tests creating, loading, and switching profiles.
 func TestProfileManagement(t *testing.T) {
 	store := new(mem.Store)