chore: fix autogroup:self with other acl rules (#2842)

hscontrol/policy/v2/filter.go

@@ -99,43 +99,50 @@ func (pol *Policy) compileFilterRulesForNode(
 			return nil, ErrInvalidAction
 		}
 
-		rule, err := pol.compileACLWithAutogroupSelf(acl, users, node, nodes)
+		aclRules, err := pol.compileACLWithAutogroupSelf(acl, users, node, nodes)
 		if err != nil {
 			log.Trace().Err(err).Msgf("compiling ACL")
 			continue
 		}
 
+		for _, rule := range aclRules {
 			if rule != nil {
 				rules = append(rules, *rule)
 			}
 		}
+	}
 
 	return rules, nil
 }
 
 // compileACLWithAutogroupSelf compiles a single ACL rule, handling
 // autogroup:self per-node while supporting all other alias types normally.
+// It returns a slice of filter rules because when an ACL has both autogroup:self
+// and other destinations, they need to be split into separate rules with different
+// source filtering logic.
 func (pol *Policy) compileACLWithAutogroupSelf(
 	acl ACL,
 	users types.Users,
 	node types.NodeView,
 	nodes views.Slice[types.NodeView],
-) (*tailcfg.FilterRule, error) {
-	// Check if any destination uses autogroup:self
-	hasAutogroupSelfInDst := false
+) ([]*tailcfg.FilterRule, error) {
+	var autogroupSelfDests []AliasWithPorts
+	var otherDests []AliasWithPorts
 
 	for _, dest := range acl.Destinations {
 		if ag, ok := dest.Alias.(*AutoGroup); ok && ag.Is(AutoGroupSelf) {
-			hasAutogroupSelfInDst = true
-			break
+			autogroupSelfDests = append(autogroupSelfDests, dest)
+		} else {
+			otherDests = append(otherDests, dest)
 		}
 	}
 
-	var srcIPs netipx.IPSetBuilder
+	protocols, _ := acl.Protocol.parseProtocol()
+	var rules []*tailcfg.FilterRule
+
+	var resolvedSrcIPs []*netipx.IPSet
 
-	// Resolve sources to only include devices from the same user as the target node.
 	for _, src := range acl.Sources {
-		// autogroup:self is not allowed in sources
 		if ag, ok := src.(*AutoGroup); ok && ag.Is(AutoGroupSelf) {
 			return nil, fmt.Errorf("autogroup:self cannot be used in sources")
 		}
@@ -147,57 +154,86 @@ func (pol *Policy) compileACLWithAutogroupSelf(
 		}
 
 		if ips != nil {
-			if hasAutogroupSelfInDst {
-				// Instead of iterating all addresses (which could be millions),
-				// check each node's IPs against the source set
+			resolvedSrcIPs = append(resolvedSrcIPs, ips)
+		}
+	}
+
+	if len(resolvedSrcIPs) == 0 {
+		return rules, nil
+	}
+
+	// Handle autogroup:self destinations (if any)
+	if len(autogroupSelfDests) > 0 {
+		// Pre-filter to same-user untagged devices once - reuse for both sources and destinations
+		sameUserNodes := make([]types.NodeView, 0)
 		for _, n := range nodes.All() {
 			if n.User().ID == node.User().ID && !n.IsTagged() {
+				sameUserNodes = append(sameUserNodes, n)
+			}
+		}
+
+		if len(sameUserNodes) > 0 {
+			// Filter sources to only same-user untagged devices
+			var srcIPs netipx.IPSetBuilder
+			for _, ips := range resolvedSrcIPs {
+				for _, n := range sameUserNodes {
 					// Check if any of this node's IPs are in the source set
 					for _, nodeIP := range n.IPs() {
 						if ips.Contains(nodeIP) {
 							n.AppendToIPSet(&srcIPs)
-								break // Found this node, move to next
+							break
 						}
 					}
 				}
 			}
-			} else {
-				// No autogroup:self in destination, use all resolved sources
-				srcIPs.AddSet(ips)
-			}
-		}
-	}
 
 			srcSet, err := srcIPs.IPSet()
 			if err != nil {
 				return nil, err
 			}
 
-	if srcSet == nil || len(srcSet.Prefixes()) == 0 {
-		// No sources resolved, skip this rule
-		return nil, nil //nolint:nilnil
-	}
-
-	protocols, _ := acl.Protocol.parseProtocol()
-
+			if srcSet != nil && len(srcSet.Prefixes()) > 0 {
 				var destPorts []tailcfg.NetPortRange
-
-	for _, dest := range acl.Destinations {
-		if ag, ok := dest.Alias.(*AutoGroup); ok && ag.Is(AutoGroupSelf) {
-			for _, n := range nodes.All() {
-				if n.User().ID == node.User().ID && !n.IsTagged() {
+				for _, dest := range autogroupSelfDests {
+					for _, n := range sameUserNodes {
 						for _, port := range dest.Ports {
 							for _, ip := range n.IPs() {
-							pr := tailcfg.NetPortRange{
+								destPorts = append(destPorts, tailcfg.NetPortRange{
 									IP:    ip.String(),
 									Ports: port,
-							}
-							destPorts = append(destPorts, pr)
+								})
 							}
 						}
 					}
 				}
-		} else {
+
+				if len(destPorts) > 0 {
+					rules = append(rules, &tailcfg.FilterRule{
+						SrcIPs:   ipSetToPrefixStringList(srcSet),
+						DstPorts: destPorts,
+						IPProto:  protocols,
+					})
+				}
+			}
+		}
+	}
+
+	if len(otherDests) > 0 {
+		var srcIPs netipx.IPSetBuilder
+
+		for _, ips := range resolvedSrcIPs {
+			srcIPs.AddSet(ips)
+		}
+
+		srcSet, err := srcIPs.IPSet()
+		if err != nil {
+			return nil, err
+		}
+
+		if srcSet != nil && len(srcSet.Prefixes()) > 0 {
+			var destPorts []tailcfg.NetPortRange
+
+			for _, dest := range otherDests {
 				ips, err := dest.Resolve(pol, users, nodes)
 				if err != nil {
 					log.Trace().Err(err).Msgf("resolving destination ips")
@@ -221,18 +257,18 @@ func (pol *Policy) compileACLWithAutogroupSelf(
 					}
 				}
 			}
-	}
 
-	if len(destPorts) == 0 {
-		// No destinations resolved, skip this rule
-		return nil, nil //nolint:nilnil
-	}
-
-	return &tailcfg.FilterRule{
+			if len(destPorts) > 0 {
+				rules = append(rules, &tailcfg.FilterRule{
 					SrcIPs:   ipSetToPrefixStringList(srcSet),
 					DstPorts: destPorts,
 					IPProto:  protocols,
-	}, nil
+				})
+			}
+		}
+	}
+
+	return rules, nil
 }
 
 func sshAction(accept bool, duration time.Duration) tailcfg.SSHAction {
@@ -260,46 +296,30 @@ func (pol *Policy) compileSSHPolicy(
 	var rules []*tailcfg.SSHRule
 
 	for index, rule := range pol.SSHs {
-		// Check if any destination uses autogroup:self
-		hasAutogroupSelfInDst := false
+		// Separate destinations into autogroup:self and others
+		// This is needed because autogroup:self requires filtering sources to same-user only,
+		// while other destinations should use all resolved sources
+		var autogroupSelfDests []Alias
+		var otherDests []Alias
+
 		for _, dst := range rule.Destinations {
 			if ag, ok := dst.(*AutoGroup); ok && ag.Is(AutoGroupSelf) {
-				hasAutogroupSelfInDst = true
-				break
-			}
-		}
-
-		// If autogroup:self is used, skip tagged nodes
-		if hasAutogroupSelfInDst && node.IsTagged() {
-			continue
-		}
-
-		var dest netipx.IPSetBuilder
-		for _, src := range rule.Destinations {
-			// Handle autogroup:self specially
-			if ag, ok := src.(*AutoGroup); ok && ag.Is(AutoGroupSelf) {
-				// For autogroup:self, only include the target user's untagged devices
-				for _, n := range nodes.All() {
-					if n.User().ID == node.User().ID && !n.IsTagged() {
-						n.AppendToIPSet(&dest)
-					}
-				}
+				autogroupSelfDests = append(autogroupSelfDests, dst)
 			} else {
-				ips, err := src.Resolve(pol, users, nodes)
-				if err != nil {
-					log.Trace().Caller().Err(err).Msgf("resolving destination ips")
-					continue
-				}
-				dest.AddSet(ips)
+				otherDests = append(otherDests, dst)
 			}
 		}
 
-		destSet, err := dest.IPSet()
+		// Note: Tagged nodes can't match autogroup:self destinations, but can still match other destinations
+
+		// Resolve sources once - we'll use them differently for each destination type
+		srcIPs, err := rule.Sources.Resolve(pol, users, nodes)
 		if err != nil {
-			return nil, err
+			log.Trace().Caller().Err(err).Msgf("SSH policy compilation failed resolving source ips for rule %+v", rule)
+			continue // Skip this rule if we can't resolve sources
 		}
 
-		if !node.InIPSet(destSet) {
+		if srcIPs == nil || len(srcIPs.Prefixes()) == 0 {
 			continue
 		}
 
@@ -313,50 +333,9 @@ func (pol *Policy) compileSSHPolicy(
 			return nil, fmt.Errorf("parsing SSH policy, unknown action %q, index: %d: %w", rule.Action, index, err)
 		}
 
-		var principals []*tailcfg.SSHPrincipal
-		srcIPs, err := rule.Sources.Resolve(pol, users, nodes)
-		if err != nil {
-			log.Trace().Caller().Err(err).Msgf("SSH policy compilation failed resolving source ips for rule %+v", rule)
-			continue // Skip this rule if we can't resolve sources
-		}
-
-		// If autogroup:self is in destinations, filter sources to same user only
-		if hasAutogroupSelfInDst {
-			var filteredSrcIPs netipx.IPSetBuilder
-			// Instead of iterating all addresses, check each node's IPs
-			for _, n := range nodes.All() {
-				if n.User().ID == node.User().ID && !n.IsTagged() {
-					// Check if any of this node's IPs are in the source set
-					for _, nodeIP := range n.IPs() {
-						if srcIPs.Contains(nodeIP) {
-							n.AppendToIPSet(&filteredSrcIPs)
-							break // Found this node, move to next
-						}
-					}
-				}
-			}
-
-			srcIPs, err = filteredSrcIPs.IPSet()
-			if err != nil {
-				return nil, err
-			}
-
-			if srcIPs == nil || len(srcIPs.Prefixes()) == 0 {
-				// No valid sources after filtering, skip this rule
-				continue
-			}
-		}
-
-		for addr := range util.IPSetAddrIter(srcIPs) {
-			principals = append(principals, &tailcfg.SSHPrincipal{
-				NodeIP: addr.String(),
-			})
-		}
-
 		userMap := make(map[string]string, len(rule.Users))
 		if rule.Users.ContainsNonRoot() {
 			userMap["*"] = "="
-
 			// by default, we do not allow root unless explicitly stated
 			userMap["root"] = ""
 		}
@@ -366,12 +345,109 @@ func (pol *Policy) compileSSHPolicy(
 		for _, u := range rule.Users.NormalUsers() {
 			userMap[u.String()] = u.String()
 		}
+
+		// Handle autogroup:self destinations (if any)
+		// Note: Tagged nodes can't match autogroup:self, so skip this block for tagged nodes
+		if len(autogroupSelfDests) > 0 && !node.IsTagged() {
+			// Build destination set for autogroup:self (same-user untagged devices only)
+			var dest netipx.IPSetBuilder
+			for _, n := range nodes.All() {
+				if n.User().ID == node.User().ID && !n.IsTagged() {
+					n.AppendToIPSet(&dest)
+				}
+			}
+
+			destSet, err := dest.IPSet()
+			if err != nil {
+				return nil, err
+			}
+
+			// Only create rule if this node is in the destination set
+			if node.InIPSet(destSet) {
+				// Filter sources to only same-user untagged devices
+				// Pre-filter to same-user untagged devices for efficiency
+				sameUserNodes := make([]types.NodeView, 0)
+				for _, n := range nodes.All() {
+					if n.User().ID == node.User().ID && !n.IsTagged() {
+						sameUserNodes = append(sameUserNodes, n)
+					}
+				}
+
+				var filteredSrcIPs netipx.IPSetBuilder
+				for _, n := range sameUserNodes {
+					// Check if any of this node's IPs are in the source set
+					for _, nodeIP := range n.IPs() {
+						if srcIPs.Contains(nodeIP) {
+							n.AppendToIPSet(&filteredSrcIPs)
+							break // Found this node, move to next
+						}
+					}
+				}
+
+				filteredSrcSet, err := filteredSrcIPs.IPSet()
+				if err != nil {
+					return nil, err
+				}
+
+				if filteredSrcSet != nil && len(filteredSrcSet.Prefixes()) > 0 {
+					var principals []*tailcfg.SSHPrincipal
+					for addr := range util.IPSetAddrIter(filteredSrcSet) {
+						principals = append(principals, &tailcfg.SSHPrincipal{
+							NodeIP: addr.String(),
+						})
+					}
+
+					if len(principals) > 0 {
 						rules = append(rules, &tailcfg.SSHRule{
 							Principals: principals,
 							SSHUsers:   userMap,
 							Action:     &action,
 						})
 					}
+				}
+			}
+		}
+
+		// Handle other destinations (if any)
+		if len(otherDests) > 0 {
+			// Build destination set for other destinations
+			var dest netipx.IPSetBuilder
+			for _, dst := range otherDests {
+				ips, err := dst.Resolve(pol, users, nodes)
+				if err != nil {
+					log.Trace().Caller().Err(err).Msgf("resolving destination ips")
+					continue
+				}
+				if ips != nil {
+					dest.AddSet(ips)
+				}
+			}
+
+			destSet, err := dest.IPSet()
+			if err != nil {
+				return nil, err
+			}
+
+			// Only create rule if this node is in the destination set
+			if node.InIPSet(destSet) {
+				// For non-autogroup:self destinations, use all resolved sources (no filtering)
+				var principals []*tailcfg.SSHPrincipal
+				for addr := range util.IPSetAddrIter(srcIPs) {
+					principals = append(principals, &tailcfg.SSHPrincipal{
+						NodeIP: addr.String(),
+					})
+				}
+
+				if len(principals) > 0 {
+					rules = append(rules, &tailcfg.SSHRule{
+						Principals: principals,
+						SSHUsers:   userMap,
+						Action:     &action,
+					})
+				}
+			}
+		}
+	}
 
 	return &tailcfg.SSHPolicy{
 		Rules: rules,

hscontrol/policy/v2/filter_test.go

@@ -1339,3 +1339,70 @@ func TestSSHWithAutogroupSelfExcludesTaggedDevices(t *testing.T) {
 		assert.Empty(t, sshPolicy2.Rules, "tagged node should get no SSH rules with autogroup:self")
 	}
 }
+
+// TestSSHWithAutogroupSelfAndMixedDestinations tests that SSH rules can have both
+// autogroup:self and other destinations (like tag:router) in the same rule, and that
+// autogroup:self filtering only applies to autogroup:self destinations, not others.
+func TestSSHWithAutogroupSelfAndMixedDestinations(t *testing.T) {
+	users := types.Users{
+		{Model: gorm.Model{ID: 1}, Name: "user1"},
+		{Model: gorm.Model{ID: 2}, Name: "user2"},
+	}
+
+	nodes := types.Nodes{
+		{User: users[0], IPv4: ap("100.64.0.1"), Hostname: "user1-device"},
+		{User: users[0], IPv4: ap("100.64.0.2"), Hostname: "user1-device2"},
+		{User: users[1], IPv4: ap("100.64.0.3"), Hostname: "user2-device"},
+		{User: users[1], IPv4: ap("100.64.0.4"), Hostname: "user2-router", ForcedTags: []string{"tag:router"}},
+	}
+
+	policy := &Policy{
+		TagOwners: TagOwners{
+			Tag("tag:router"): Owners{up("user2@")},
+		},
+		SSHs: []SSH{
+			{
+				Action:       "accept",
+				Sources:      SSHSrcAliases{agp("autogroup:member")},
+				Destinations: SSHDstAliases{agp("autogroup:self"), tp("tag:router")},
+				Users:        []SSHUser{"admin"},
+			},
+		},
+	}
+
+	err := policy.validate()
+	require.NoError(t, err)
+
+	// Test 1: Compile for user1's device (should only match autogroup:self destination)
+	node1 := nodes[0].View()
+	sshPolicy1, err := policy.compileSSHPolicy(users, node1, nodes.ViewSlice())
+	require.NoError(t, err)
+	require.NotNil(t, sshPolicy1)
+	require.Len(t, sshPolicy1.Rules, 1, "user1's device should have 1 SSH rule (autogroup:self)")
+
+	// Verify autogroup:self rule has filtered sources (only same-user devices)
+	selfRule := sshPolicy1.Rules[0]
+	require.Len(t, selfRule.Principals, 2, "autogroup:self rule should only have user1's devices")
+	selfPrincipals := make([]string, len(selfRule.Principals))
+	for i, p := range selfRule.Principals {
+		selfPrincipals[i] = p.NodeIP
+	}
+	require.ElementsMatch(t, []string{"100.64.0.1", "100.64.0.2"}, selfPrincipals,
+		"autogroup:self rule should only include same-user untagged devices")
+
+	// Test 2: Compile for router (should only match tag:router destination)
+	routerNode := nodes[3].View() // user2-router
+	sshPolicyRouter, err := policy.compileSSHPolicy(users, routerNode, nodes.ViewSlice())
+	require.NoError(t, err)
+	require.NotNil(t, sshPolicyRouter)
+	require.Len(t, sshPolicyRouter.Rules, 1, "router should have 1 SSH rule (tag:router)")
+
+	routerRule := sshPolicyRouter.Rules[0]
+	routerPrincipals := make([]string, len(routerRule.Principals))
+	for i, p := range routerRule.Principals {
+		routerPrincipals[i] = p.NodeIP
+	}
+	require.Contains(t, routerPrincipals, "100.64.0.1", "router rule should include user1's device (unfiltered sources)")
+	require.Contains(t, routerPrincipals, "100.64.0.2", "router rule should include user1's other device (unfiltered sources)")
+	require.Contains(t, routerPrincipals, "100.64.0.3", "router rule should include user2's device (unfiltered sources)")
+}

hscontrol/policy/v2/policy_test.go

@@ -2,6 +2,7 @@ package v2
 
 import (
 	"net/netip"
+	"slices"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -439,3 +440,82 @@ func TestAutogroupSelfReducedVsUnreducedRules(t *testing.T) {
 	require.Empty(t, peerMap[node1.ID], "node1 should have no peers (can only reach itself)")
 	require.Empty(t, peerMap[node2.ID], "node2 should have no peers")
 }
+
+// When separate ACL rules exist (one with autogroup:self, one with tag:router),
+// the autogroup:self rule should not prevent the tag:router rule from working.
+// This ensures that autogroup:self doesn't interfere with other ACL rules.
+func TestAutogroupSelfWithOtherRules(t *testing.T) {
+	users := types.Users{
+		{Model: gorm.Model{ID: 1}, Name: "test-1", Email: "test-1@example.com"},
+		{Model: gorm.Model{ID: 2}, Name: "test-2", Email: "test-2@example.com"},
+	}
+
+	// test-1 has a regular device
+	test1Node := &types.Node{
+		ID:       1,
+		Hostname: "test-1-device",
+		IPv4:     ap("100.64.0.1"),
+		IPv6:     ap("fd7a:115c:a1e0::1"),
+		User:     users[0],
+		UserID:   users[0].ID,
+		Hostinfo: &tailcfg.Hostinfo{},
+	}
+
+	// test-2 has a router device with tag:node-router
+	test2RouterNode := &types.Node{
+		ID:         2,
+		Hostname:   "test-2-router",
+		IPv4:       ap("100.64.0.2"),
+		IPv6:       ap("fd7a:115c:a1e0::2"),
+		User:       users[1],
+		UserID:     users[1].ID,
+		ForcedTags: []string{"tag:node-router"},
+		Hostinfo:   &tailcfg.Hostinfo{},
+	}
+
+	nodes := types.Nodes{test1Node, test2RouterNode}
+
+	// This matches the exact policy from issue #2838:
+	// - First rule: autogroup:member -> autogroup:self (allows users to see their own devices)
+	// - Second rule: group:home -> tag:node-router (should allow group members to see router)
+	policy := `{
+		"groups": {
+			"group:home": ["test-1@example.com", "test-2@example.com"]
+		},
+		"tagOwners": {
+			"tag:node-router": ["group:home"]
+		},
+		"acls": [
+			{
+				"action": "accept",
+				"src": ["autogroup:member"],
+				"dst": ["autogroup:self:*"]
+			},
+			{
+				"action": "accept",
+				"src": ["group:home"],
+				"dst": ["tag:node-router:*"]
+			}
+		]
+	}`
+
+	pm, err := NewPolicyManager([]byte(policy), users, nodes.ViewSlice())
+	require.NoError(t, err)
+
+	peerMap := pm.BuildPeerMap(nodes.ViewSlice())
+
+	// test-1 (in group:home) should see:
+	// 1. Their own node (from autogroup:self rule)
+	// 2. The router node (from group:home -> tag:node-router rule)
+	test1Peers := peerMap[test1Node.ID]
+
+	// Verify test-1 can see the router (group:home -> tag:node-router rule)
+	require.True(t, slices.ContainsFunc(test1Peers, func(n types.NodeView) bool {
+		return n.ID() == test2RouterNode.ID
+	}), "test-1 should see test-2's router via group:home -> tag:node-router rule, even when autogroup:self rule exists (issue #2838)")
+
+	// Verify that test-1 has filter rules (including autogroup:self and tag:node-router access)
+	rules, err := pm.FilterForNode(test1Node.View())
+	require.NoError(t, err)
+	require.NotEmpty(t, rules, "test-1 should have filter rules from both ACL rules")
+}

integration/acl_test.go

@@ -1611,11 +1611,29 @@ func TestACLAutogroupTagged(t *testing.T) {
 }
 
 // Test that only devices owned by the same user can access each other and cannot access devices of other users
+// Test structure:
+// - user1: 2 regular nodes (tests autogroup:self for same-user access)
+// - user2: 2 regular nodes (tests autogroup:self for same-user access and cross-user isolation)
+// - user-router: 1 node with tag:router-node (tests that autogroup:self doesn't interfere with other rules)
 func TestACLAutogroupSelf(t *testing.T) {
 	IntegrationSkip(t)
 
-	scenario := aclScenario(t,
-		&policyv2.Policy{
+	// Policy with TWO separate ACL rules:
+	// 1. autogroup:member -> autogroup:self (same-user access)
+	// 2. group:home -> tag:router-node (router access)
+	// This tests that autogroup:self doesn't prevent other rules from working
+	policy := &policyv2.Policy{
+		Groups: policyv2.Groups{
+			policyv2.Group("group:home"): []policyv2.Username{
+				policyv2.Username("user1@"),
+				policyv2.Username("user2@"),
+			},
+		},
+		TagOwners: policyv2.TagOwners{
+			policyv2.Tag("tag:router-node"): policyv2.Owners{
+				usernameOwner("user-router@"),
+			},
+		},
 		ACLs: []policyv2.ACL{
 			{
 				Action:  "accept",
@@ -1624,24 +1642,139 @@ func TestACLAutogroupSelf(t *testing.T) {
 					aliasWithPorts(ptr.To(policyv2.AutoGroupSelf), tailcfg.PortRangeAny),
 				},
 			},
+			{
+				Action:  "accept",
+				Sources: []policyv2.Alias{groupp("group:home")},
+				Destinations: []policyv2.AliasWithPorts{
+					aliasWithPorts(tagp("tag:router-node"), tailcfg.PortRangeAny),
 				},
 			},
-		2,
-	)
+			{
+				Action:  "accept",
+				Sources: []policyv2.Alias{tagp("tag:router-node")},
+				Destinations: []policyv2.AliasWithPorts{
+					aliasWithPorts(groupp("group:home"), tailcfg.PortRangeAny),
+				},
+			},
+		},
+	}
+
+	// Create custom scenario: user1 and user2 with regular nodes, plus user-router with tagged node
+	spec := ScenarioSpec{
+		NodesPerUser: 2,
+		Users:        []string{"user1", "user2"},
+	}
+
+	scenario, err := NewScenario(spec)
+	require.NoError(t, err)
 	defer scenario.ShutdownAssertNoPanics(t)
 
-	err := scenario.WaitForTailscaleSyncWithPeerCount(1, integrationutil.PeerSyncTimeout(), integrationutil.PeerSyncRetryInterval())
+	err = scenario.CreateHeadscaleEnv(
+		[]tsic.Option{
+			tsic.WithNetfilter("off"),
+			tsic.WithDockerEntrypoint([]string{
+				"/bin/sh",
+				"-c",
+				"/bin/sleep 3 ; apk add python3 curl ; update-ca-certificates ; python3 -m http.server --bind :: 80 & tailscaled --tun=tsdev",
+			}),
+			tsic.WithDockerWorkdir("/"),
+		},
+		hsic.WithACLPolicy(policy),
+		hsic.WithTestName("acl-autogroup-self"),
+		hsic.WithEmbeddedDERPServerOnly(),
+		hsic.WithTLS(),
+	)
 	require.NoError(t, err)
 
+	// Add router node for user-router (single shared router node)
+	networks := scenario.Networks()
+	var network *dockertest.Network
+	if len(networks) > 0 {
+		network = networks[0]
+	}
+
+	headscale, err := scenario.Headscale()
+	require.NoError(t, err)
+
+	routerUser, err := scenario.CreateUser("user-router")
+	require.NoError(t, err)
+
+	authKey, err := scenario.CreatePreAuthKey(routerUser.GetId(), true, false)
+	require.NoError(t, err)
+
+	// Create router node (tagged with tag:router-node)
+	routerClient, err := tsic.New(
+		scenario.Pool(),
+		"unstable",
+		tsic.WithCACert(headscale.GetCert()),
+		tsic.WithHeadscaleName(headscale.GetHostname()),
+		tsic.WithNetwork(network),
+		tsic.WithTags([]string{"tag:router-node"}),
+		tsic.WithNetfilter("off"),
+		tsic.WithDockerEntrypoint([]string{
+			"/bin/sh",
+			"-c",
+			"/bin/sleep 3 ; apk add python3 curl ; update-ca-certificates ; python3 -m http.server --bind :: 80 & tailscaled --tun=tsdev",
+		}),
+		tsic.WithDockerWorkdir("/"),
+	)
+	require.NoError(t, err)
+
+	err = routerClient.WaitForNeedsLogin(integrationutil.PeerSyncTimeout())
+	require.NoError(t, err)
+
+	err = routerClient.Login(headscale.GetEndpoint(), authKey.GetKey())
+	require.NoError(t, err)
+
+	err = routerClient.WaitForRunning(integrationutil.PeerSyncTimeout())
+	require.NoError(t, err)
+
+	userRouterObj := scenario.GetOrCreateUser("user-router")
+	userRouterObj.Clients[routerClient.Hostname()] = routerClient
+
 	user1Clients, err := scenario.GetClients("user1")
 	require.NoError(t, err)
-
 	user2Clients, err := scenario.GetClients("user2")
 	require.NoError(t, err)
 
-	// Test that user1's devices can access each other
+	var user1Regular, user2Regular []TailscaleClient
 	for _, client := range user1Clients {
-		for _, peer := range user1Clients {
+		status, err := client.Status()
+		require.NoError(t, err)
+		if status.Self != nil && (status.Self.Tags == nil || status.Self.Tags.Len() == 0) {
+			user1Regular = append(user1Regular, client)
+		}
+	}
+	for _, client := range user2Clients {
+		status, err := client.Status()
+		require.NoError(t, err)
+		if status.Self != nil && (status.Self.Tags == nil || status.Self.Tags.Len() == 0) {
+			user2Regular = append(user2Regular, client)
+		}
+	}
+
+	require.NotEmpty(t, user1Regular, "user1 should have regular (untagged) devices")
+	require.NotEmpty(t, user2Regular, "user2 should have regular (untagged) devices")
+	require.NotNil(t, routerClient, "router node should exist")
+
+	// Wait for all nodes to sync with their expected peer counts
+	// With our ACL policy:
+	// - Regular nodes (user1/user2): 1 same-user regular peer + 1 router-node = 2 peers
+	// - Router node: 2 user1 regular + 2 user2 regular = 4 peers
+	for _, client := range user1Regular {
+		err := client.WaitForPeers(2, integrationutil.PeerSyncTimeout(), integrationutil.PeerSyncRetryInterval())
+		require.NoError(t, err, "user1 regular device %s should see 2 peers (1 same-user peer + 1 router)", client.Hostname())
+	}
+	for _, client := range user2Regular {
+		err := client.WaitForPeers(2, integrationutil.PeerSyncTimeout(), integrationutil.PeerSyncRetryInterval())
+		require.NoError(t, err, "user2 regular device %s should see 2 peers (1 same-user peer + 1 router)", client.Hostname())
+	}
+	err = routerClient.WaitForPeers(4, integrationutil.PeerSyncTimeout(), integrationutil.PeerSyncRetryInterval())
+	require.NoError(t, err, "router should see 4 peers (all group:home regular nodes)")
+
+	// Test that user1's regular devices can access each other
+	for _, client := range user1Regular {
+		for _, peer := range user1Regular {
 			if client.Hostname() == peer.Hostname() {
 				continue
 			}
@@ -1656,13 +1789,13 @@ func TestACLAutogroupSelf(t *testing.T) {
 				result, err := client.Curl(url)
 				assert.NoError(c, err)
 				assert.Len(c, result, 13)
-			}, 10*time.Second, 200*time.Millisecond, "user1 device should reach other user1 device")
+			}, 10*time.Second, 200*time.Millisecond, "user1 device should reach other user1 device via autogroup:self")
 		}
 	}
 
-	// Test that user2's devices can access each other
-	for _, client := range user2Clients {
-		for _, peer := range user2Clients {
+	// Test that user2's regular devices can access each other
+	for _, client := range user2Regular {
+		for _, peer := range user2Regular {
 			if client.Hostname() == peer.Hostname() {
 				continue
 			}
@@ -1677,36 +1810,64 @@ func TestACLAutogroupSelf(t *testing.T) {
 				result, err := client.Curl(url)
 				assert.NoError(c, err)
 				assert.Len(c, result, 13)
-			}, 10*time.Second, 200*time.Millisecond, "user2 device should reach other user2 device")
+			}, 10*time.Second, 200*time.Millisecond, "user2 device should reach other user2 device via autogroup:self")
 		}
 	}
 
-	// Test that devices from different users cannot access each other
-	for _, client := range user1Clients {
-		for _, peer := range user2Clients {
+	// Test that user1's regular devices can access router-node
+	for _, client := range user1Regular {
+		fqdn, err := routerClient.FQDN()
+		require.NoError(t, err)
+		url := fmt.Sprintf("http://%s/etc/hostname", fqdn)
+		t.Logf("url from %s (user1) to %s (router-node) - should SUCCEED", client.Hostname(), fqdn)
+
+		assert.EventuallyWithT(t, func(c *assert.CollectT) {
+			result, err := client.Curl(url)
+			assert.NoError(c, err)
+			assert.NotEmpty(c, result, "user1 should be able to access router-node via group:home -> tag:router-node rule")
+		}, 10*time.Second, 200*time.Millisecond, "user1 device should reach router-node (proves autogroup:self doesn't interfere)")
+	}
+
+	// Test that user2's regular devices can access router-node
+	for _, client := range user2Regular {
+		fqdn, err := routerClient.FQDN()
+		require.NoError(t, err)
+		url := fmt.Sprintf("http://%s/etc/hostname", fqdn)
+		t.Logf("url from %s (user2) to %s (router-node) - should SUCCEED", client.Hostname(), fqdn)
+
+		assert.EventuallyWithT(t, func(c *assert.CollectT) {
+			result, err := client.Curl(url)
+			assert.NoError(c, err)
+			assert.NotEmpty(c, result, "user2 should be able to access router-node via group:home -> tag:router-node rule")
+		}, 10*time.Second, 200*time.Millisecond, "user2 device should reach router-node (proves autogroup:self doesn't interfere)")
+	}
+
+	// Test that devices from different users cannot access each other's regular devices
+	for _, client := range user1Regular {
+		for _, peer := range user2Regular {
 			fqdn, err := peer.FQDN()
 			require.NoError(t, err)
 
 			url := fmt.Sprintf("http://%s/etc/hostname", fqdn)
-			t.Logf("url from %s (user1) to %s (user2) - should FAIL", client.Hostname(), fqdn)
+			t.Logf("url from %s (user1) to %s (user2 regular) - should FAIL", client.Hostname(), fqdn)
 
 			result, err := client.Curl(url)
-			assert.Empty(t, result, "user1 should not be able to access user2's devices with autogroup:self")
-			assert.Error(t, err, "connection from user1 to user2 should fail")
+			assert.Empty(t, result, "user1 should not be able to access user2's regular devices (autogroup:self isolation)")
+			assert.Error(t, err, "connection from user1 to user2 regular device should fail")
 		}
 	}
 
-	for _, client := range user2Clients {
-		for _, peer := range user1Clients {
+	for _, client := range user2Regular {
+		for _, peer := range user1Regular {
 			fqdn, err := peer.FQDN()
 			require.NoError(t, err)
 
 			url := fmt.Sprintf("http://%s/etc/hostname", fqdn)
-			t.Logf("url from %s (user2) to %s (user1) - should FAIL", client.Hostname(), fqdn)
+			t.Logf("url from %s (user2) to %s (user1 regular) - should FAIL", client.Hostname(), fqdn)
 
 			result, err := client.Curl(url)
-			assert.Empty(t, result, "user2 should not be able to access user1's devices with autogroup:self")
-			assert.Error(t, err, "connection from user2 to user1 should fail")
+			assert.Empty(t, result, "user2 should not be able to access user1's regular devices (autogroup:self isolation)")
+			assert.Error(t, err, "connection from user2 to user1 regular device should fail")
 		}
 	}
 }