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| 1 | +package workspacesdk_test |
| 2 | + |
| 3 | +import ( |
| 4 | + "context" |
| 5 | + "errors" |
| 6 | + "fmt" |
| 7 | + "net" |
| 8 | + "net/http" |
| 9 | + "net/netip" |
| 10 | + "strings" |
| 11 | + "sync/atomic" |
| 12 | + "testing" |
| 13 | + |
| 14 | + "github.com/google/uuid" |
| 15 | + "github.com/stretchr/testify/assert" |
| 16 | + "github.com/stretchr/testify/require" |
| 17 | + "tailscale.com/tailcfg" |
| 18 | + |
| 19 | + "github.com/coder/coder/v2/codersdk/workspacesdk" |
| 20 | + "github.com/coder/coder/v2/tailnet" |
| 21 | + "github.com/coder/coder/v2/tailnet/proto" |
| 22 | + "github.com/coder/coder/v2/tailnet/tailnettest" |
| 23 | + "github.com/coder/coder/v2/testutil" |
| 24 | +) |
| 25 | + |
| 26 | +func TestAgentConnRejectsCrossAgentRedirects(t *testing.T) { |
| 27 | + t.Parallel() |
| 28 | + |
| 29 | + derpMap, _ := tailnettest.RunDERPAndSTUN(t) |
| 30 | + cases := []struct { |
| 31 | + name string |
| 32 | + status int |
| 33 | + invoke func(context.Context, workspacesdk.AgentConn) error |
| 34 | + }{ |
| 35 | + { |
| 36 | + name: "get 302", |
| 37 | + status: http.StatusFound, |
| 38 | + invoke: func(ctx context.Context, conn workspacesdk.AgentConn) error { |
| 39 | + _, err := conn.ListeningPorts(ctx) |
| 40 | + return err |
| 41 | + }, |
| 42 | + }, |
| 43 | + { |
| 44 | + name: "post 307", |
| 45 | + status: http.StatusTemporaryRedirect, |
| 46 | + invoke: func(ctx context.Context, conn workspacesdk.AgentConn) error { |
| 47 | + return conn.WriteFile(ctx, "/tmp/attacker", strings.NewReader("redirect-body")) |
| 48 | + }, |
| 49 | + }, |
| 50 | + { |
| 51 | + name: "post 308", |
| 52 | + status: http.StatusPermanentRedirect, |
| 53 | + invoke: func(ctx context.Context, conn workspacesdk.AgentConn) error { |
| 54 | + return conn.WriteFile(ctx, "/tmp/attacker", strings.NewReader("redirect-body")) |
| 55 | + }, |
| 56 | + }, |
| 57 | + } |
| 58 | + |
| 59 | + for _, tc := range cases { |
| 60 | + t.Run(tc.name, func(t *testing.T) { |
| 61 | + t.Parallel() |
| 62 | + |
| 63 | + ctx := testutil.Context(t, testutil.WaitMedium) |
| 64 | + |
| 65 | + clientID := uuid.New() |
| 66 | + attackerID := uuid.New() |
| 67 | + victimID := uuid.New() |
| 68 | + clientConn, _ := newTailnetConn(t, derpMap, clientID, "client") |
| 69 | + attackerConn, attackerIP := newTailnetConn(t, derpMap, attackerID, "attacker") |
| 70 | + victimConn, victimIP := newTailnetConn(t, derpMap, victimID, "victim") |
| 71 | + stitchTailnet(t, map[uuid.UUID]*tailnet.Conn{ |
| 72 | + clientID: clientConn, |
| 73 | + attackerID: attackerConn, |
| 74 | + victimID: victimConn, |
| 75 | + }) |
| 76 | + |
| 77 | + var victimHit atomic.Bool |
| 78 | + victimRouter := http.NewServeMux() |
| 79 | + victimRouter.HandleFunc("/api/v0/listening-ports", func(rw http.ResponseWriter, _ *http.Request) { |
| 80 | + victimHit.Store(true) |
| 81 | + rw.Header().Set("Content-Type", "application/json") |
| 82 | + _, _ = rw.Write([]byte(`{"ports":[]}`)) |
| 83 | + }) |
| 84 | + victimRouter.HandleFunc("/api/v0/write-file", func(rw http.ResponseWriter, _ *http.Request) { |
| 85 | + victimHit.Store(true) |
| 86 | + rw.WriteHeader(http.StatusOK) |
| 87 | + }) |
| 88 | + serveTailnetHTTP(t, victimConn, victimRouter) |
| 89 | + |
| 90 | + victimBaseURL := fmt.Sprintf("http://[%s]:%d", victimIP, workspacesdk.AgentHTTPAPIServerPort) |
| 91 | + attackerRouter := http.NewServeMux() |
| 92 | + attackerRouter.HandleFunc("/", func(rw http.ResponseWriter, r *http.Request) { |
| 93 | + http.Redirect(rw, r, victimBaseURL+r.URL.RequestURI(), tc.status) |
| 94 | + }) |
| 95 | + serveTailnetHTTP(t, attackerConn, attackerRouter) |
| 96 | + |
| 97 | + require.True(t, clientConn.AwaitReachable(ctx, attackerIP)) |
| 98 | + require.True(t, clientConn.AwaitReachable(ctx, victimIP)) |
| 99 | + |
| 100 | + conn := workspacesdk.NewAgentConn(clientConn, workspacesdk.AgentConnOptions{ |
| 101 | + AgentID: attackerID, |
| 102 | + }) |
| 103 | + |
| 104 | + err := tc.invoke(ctx, conn) |
| 105 | + require.Error(t, err) |
| 106 | + require.False(t, victimHit.Load()) |
| 107 | + }) |
| 108 | + } |
| 109 | +} |
| 110 | + |
| 111 | +// TestAgentConnAppHTTPClientRefusesRedirects verifies the app HTTP client does |
| 112 | +// not follow redirects. |
| 113 | +func TestAgentConnAppHTTPClientRefusesRedirects(t *testing.T) { |
| 114 | + t.Parallel() |
| 115 | + |
| 116 | + tailnetConn, err := tailnet.NewConn(&tailnet.Options{ |
| 117 | + Addresses: []netip.Prefix{tailnet.TailscaleServicePrefix.RandomPrefix()}, |
| 118 | + Logger: testutil.Logger(t), |
| 119 | + }) |
| 120 | + require.NoError(t, err) |
| 121 | + t.Cleanup(func() { |
| 122 | + _ = tailnetConn.Close() |
| 123 | + }) |
| 124 | + |
| 125 | + conn := workspacesdk.NewAgentConn(tailnetConn, workspacesdk.AgentConnOptions{ |
| 126 | + AgentID: uuid.New(), |
| 127 | + }) |
| 128 | + |
| 129 | + client := conn.AppHTTPClient() |
| 130 | + require.NotNil(t, client.CheckRedirect) |
| 131 | + req, err := http.NewRequestWithContext(context.Background(), http.MethodGet, "http://example.invalid/", nil) |
| 132 | + require.NoError(t, err) |
| 133 | + require.ErrorIs(t, client.CheckRedirect(req, nil), http.ErrUseLastResponse) |
| 134 | +} |
| 135 | + |
| 136 | +func newTailnetConn(t *testing.T, derpMap *tailcfg.DERPMap, id uuid.UUID, name string) (*tailnet.Conn, netip.Addr) { |
| 137 | + t.Helper() |
| 138 | + |
| 139 | + addr := tailnet.TailscaleServicePrefix.AddrFromUUID(id) |
| 140 | + conn, err := tailnet.NewConn(&tailnet.Options{ |
| 141 | + ID: id, |
| 142 | + Addresses: []netip.Prefix{netip.PrefixFrom(addr, 128)}, |
| 143 | + Logger: testutil.Logger(t).Named(name), |
| 144 | + DERPMap: derpMap, |
| 145 | + }) |
| 146 | + require.NoError(t, err) |
| 147 | + t.Cleanup(func() { |
| 148 | + assert.NoError(t, conn.Close()) |
| 149 | + }) |
| 150 | + |
| 151 | + return conn, addr |
| 152 | +} |
| 153 | + |
| 154 | +func serveTailnetHTTP(t *testing.T, conn *tailnet.Conn, handler http.Handler) { |
| 155 | + t.Helper() |
| 156 | + |
| 157 | + ln, err := conn.Listen("tcp", fmt.Sprintf(":%d", workspacesdk.AgentHTTPAPIServerPort)) |
| 158 | + require.NoError(t, err) |
| 159 | + |
| 160 | + server := &http.Server{Handler: handler, ReadHeaderTimeout: testutil.WaitShort} |
| 161 | + t.Cleanup(func() { |
| 162 | + assert.NoError(t, server.Close()) |
| 163 | + assert.NoError(t, ln.Close()) |
| 164 | + }) |
| 165 | + |
| 166 | + go func() { |
| 167 | + err := server.Serve(ln) |
| 168 | + if err != nil && !errors.Is(err, net.ErrClosed) && !errors.Is(err, http.ErrServerClosed) { |
| 169 | + assert.NoError(t, err) |
| 170 | + } |
| 171 | + }() |
| 172 | +} |
| 173 | + |
| 174 | +// stitchTailnet cross-programs every conn's node into every other conn, the |
| 175 | +// N-peer analog of tailnet's stitch test helper, so the peers can reach each |
| 176 | +// other without a coordinator. |
| 177 | +func stitchTailnet(t *testing.T, conns map[uuid.UUID]*tailnet.Conn) { |
| 178 | + t.Helper() |
| 179 | + |
| 180 | + sendNode := func(srcID uuid.UUID, node *tailnet.Node) { |
| 181 | + protoNode, err := tailnet.NodeToProto(node) |
| 182 | + if !assert.NoError(t, err) { |
| 183 | + return |
| 184 | + } |
| 185 | + for dstID, dst := range conns { |
| 186 | + if dstID == srcID { |
| 187 | + continue |
| 188 | + } |
| 189 | + err = dst.UpdatePeers([]*proto.CoordinateResponse_PeerUpdate{{ |
| 190 | + Id: srcID[:], |
| 191 | + Node: protoNode, |
| 192 | + Kind: proto.CoordinateResponse_PeerUpdate_NODE, |
| 193 | + }}) |
| 194 | + assert.NoError(t, err) |
| 195 | + } |
| 196 | + } |
| 197 | + |
| 198 | + for srcID, src := range conns { |
| 199 | + src.SetNodeCallback(func(node *tailnet.Node) { |
| 200 | + sendNode(srcID, node) |
| 201 | + }) |
| 202 | + if node := src.Node(); node != nil { |
| 203 | + sendNode(srcID, node) |
| 204 | + } |
| 205 | + } |
| 206 | + |
| 207 | + t.Cleanup(func() { |
| 208 | + for _, conn := range conns { |
| 209 | + conn.SetNodeCallback(nil) |
| 210 | + } |
| 211 | + }) |
| 212 | +} |
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