cmd/tailscale: propagate tailscaled 403s as AccessDeniedErrors

So Linux/etc CLI users get helpful advice to run tailscale
with --operator=$USER when they try to 'tailscale file {cp,get}'
but are mysteriously forbidden.

Signed-off-by: David Eger <eger@google.com>
Signed-off-by: David Eger <david.eger@gmail.com>

client/tailscale/tailscale.go

@@ -104,6 +104,10 @@ func doLocalRequestNiceError(req *http.Request) (*http.Response, error) {
 		if server := res.Header.Get("Tailscale-Version"); server != "" && server != version.Long && onVersionMismatch != nil {
 			onVersionMismatch(version.Long, server)
 		}
+		if res.StatusCode == 403 {
+			all, _ := ioutil.ReadAll(res.Body)
+			return nil, &AccessDeniedError{errors.New(errorMessageFromBody(all))}
+		}
 		return res, nil
 	}
 	if ue, ok := err.(*url.Error); ok {
@@ -179,10 +183,6 @@ func send(ctx context.Context, method, path string, wantStatus int, body io.Read
 		return nil, err
 	}
 	if res.StatusCode != wantStatus {
-		if res.StatusCode == 403 {
-			return nil, &AccessDeniedError{errors.New(errorMessageFromBody(slurp))}
-		}
-		err := fmt.Errorf("HTTP %s: %s (expected %v)", res.Status, slurp, wantStatus)
 		return nil, bestError(err, slurp)
 	}
 	return slurp, nil
@@ -294,7 +294,7 @@ func GetWaitingFile(ctx context.Context, baseName string) (rc io.ReadCloser, siz
 	if err != nil {
 		return nil, 0, err
 	}
-	res, err := DoLocalRequest(req)
+	res, err := doLocalRequestNiceError(req)
 	if err != nil {
 		return nil, 0, err
 	}
@@ -343,7 +343,7 @@ func PushFile(ctx context.Context, target tailcfg.StableNodeID, size int64, name
 		return nil
 	}
 	all, _ := io.ReadAll(res.Body)
-	return fmt.Errorf("%s: %s", res.Status, all)
+	return bestError(fmt.Errorf("%s: %s", res.Status, all), all)
 }
 
 func CheckIPForwarding(ctx context.Context) error {

cmd/tailscale/cli/cert.go

@@ -13,7 +13,6 @@ import (
 	"log"
 	"net/http"
 	"os"
-	"runtime"
 	"strings"
 
 	"github.com/peterbourgon/ff/v3/ffcli"
@@ -92,9 +91,6 @@ func runCert(ctx context.Context, args []string) error {
 		certArgs.keyFile = domain + ".key"
 	}
 	certPEM, keyPEM, err := tailscale.CertPair(ctx, domain)
-	if tailscale.IsAccessDeniedError(err) && os.Getuid() != 0 && runtime.GOOS != "windows" {
-		return fmt.Errorf("%v\n\nUse 'sudo tailscale cert' or 'tailscale up --operator=$USER' to not require root.", err)
-	}
 	if err != nil {
 		return err
 	}

cmd/tailscale/cli/cli.go

@@ -171,6 +171,9 @@ change in the future.
 	})
 
 	err := rootCmd.Run(context.Background())
+	if tailscale.IsAccessDeniedError(err) && os.Getuid() != 0 && runtime.GOOS != "windows" {
+		return fmt.Errorf("%v\n\nUse 'sudo tailscale %s' or 'tailscale up --operator=$USER' to not require root.", err, strings.Join(args, " "))
+	}
 	if errors.Is(err, flag.ErrHelp) {
 		return nil
 	}

cmd/tailscale/cli/file.go

@@ -324,7 +324,7 @@ func runFileGet(ctx context.Context, args []string) error {
 	for {
 		wfs, err = tailscale.WaitingFiles(ctx)
 		if err != nil {
-			return fmt.Errorf("getting WaitingFiles: %v", err)
+			return fmt.Errorf("getting WaitingFiles: %w", err)
 		}
 		if len(wfs) != 0 || !getArgs.wait {
 			break
@@ -379,7 +379,7 @@ func wipeInbox(ctx context.Context) error {
 	}
 	wfs, err := tailscale.WaitingFiles(ctx)
 	if err != nil {
-		return fmt.Errorf("getting WaitingFiles: %v", err)
+		return fmt.Errorf("getting WaitingFiles: %w", err)
 	}
 	deleted := 0
 	for _, wf := range wfs {