fix(remote): abort the bootstrap when the installer cannot be fetched

apps/cinc/cmd/node_test.go

@@ -535,7 +535,7 @@ func TestNodeBootstrapDryRunCommand(t *testing.T) {
 	}
 	got := buf.String()
 	for _, want := range []string{
-		"curl -L 'https://omnitruck.cinc.sh/install.sh'",
+		"curl -fsSL 'https://omnitruck.cinc.sh/install.sh'",
 		"chef_server_url 'https://cinc.example.test/organizations/acme'",
 		"node_name 'web01'",
 		"\"run_list\": [",

cli/remote/bootstrap.go

@@ -78,10 +78,20 @@ func BootstrapCommand(opts BootstrapOptions) (string, error) {
 	}
 	commands := []string{
 		"set -e",
-		// Trust assumption: this pipes the installer script straight into a
-		// shell, so the target trusts opts.BootstrapURL (HTTPS omnitruck by
-		// default) and its TLS chain — standard Chef/Cinc bootstrap behavior.
-		"curl -L " + shellQuote(opts.BootstrapURL) + " | " + prefix + "bash -s --" + installArgs,
+		// The installer is downloaded to a file and then run, rather than
+		// piped into a shell. A pipeline reports only the exit status of its
+		// last command, so `curl ... | bash` hides a failed download from
+		// `set -e`: the script would carry on and run a cinc-client that was
+		// never installed. curl -f turns an HTTP error into a failure instead
+		// of saving the error page as the "installer".
+		//
+		// Trust assumption is unchanged: the target executes whatever
+		// opts.BootstrapURL serves (HTTPS omnitruck by default), so it trusts
+		// that host and its TLS chain, as with any Chef/Cinc bootstrap.
+		`CINC_INSTALLER="$(mktemp)"`,
+		`trap 'rm -f "$CINC_INSTALLER"' EXIT`,
+		"curl -fsSL " + shellQuote(opts.BootstrapURL) + ` -o "$CINC_INSTALLER"`,
+		prefix + `bash "$CINC_INSTALLER"` + installArgs,
 		prefix + "mkdir -p /etc/cinc",
 		// Create the private key 0600 *before* writing, so it is never
 		// world-readable on the target (tee would otherwise create it with the

cli/remote/bootstrap_test.go

@@ -21,7 +21,8 @@ func TestBootstrapCommandBuildsCincClientScript(t *testing.T) {
 		t.Fatalf("BootstrapCommand: %v", err)
 	}
 	for _, want := range []string{
-		"curl -L 'https://omnitruck.cinc.sh/install.sh' | sudo bash -s -- -v '18'",
+		"curl -fsSL 'https://omnitruck.cinc.sh/install.sh' -o",
+		"sudo bash \"$CINC_INSTALLER\" -v '18'",
 		"sudo mkdir -p /etc/cinc",
 		"sudo install -m 0600 /dev/null /etc/cinc/client.pem",
 		"chef_server_url 'https://cinc.example.test/organizations/acme'",
@@ -37,6 +38,47 @@ func TestBootstrapCommandBuildsCincClientScript(t *testing.T) {
 	}
 }
 
+// TestBootstrapCommandStopsWhenTheInstallerCannotBeFetched pins that a failed
+// download aborts the bootstrap. `curl ... | bash` reports only bash's status,
+// so under plain `set -e` a 404 or a TLS failure was swallowed and the script
+// carried on to run a cinc-client that had never been installed.
+func TestBootstrapCommandStopsWhenTheInstallerCannotBeFetched(t *testing.T) {
+	cmd, err := BootstrapCommand(BootstrapOptions{
+		NodeName:     "web01",
+		ServerURL:    "https://cinc.example.test/organizations/acme",
+		ClientKeyPEM: "PRIVATE KEY",
+		Sudo:         true,
+	})
+	if err != nil {
+		t.Fatalf("BootstrapCommand: %v", err)
+	}
+	if strings.Contains(cmd, "| sudo bash") || strings.Contains(cmd, "| bash") {
+		t.Errorf("installer is still piped into a shell, so its exit status is lost:\n%s", cmd)
+	}
+	// -f makes curl fail on an HTTP error rather than saving the error page.
+	if !strings.Contains(cmd, "curl -fsSL") {
+		t.Errorf("curl should use -f so HTTP errors are failures:\n%s", cmd)
+	}
+	if !strings.Contains(cmd, "set -e") {
+		t.Errorf("script should still abort on the first failing command:\n%s", cmd)
+	}
+}
+
+// The downloaded installer is removed even when a later step fails.
+func TestBootstrapCommandCleansUpTheInstaller(t *testing.T) {
+	cmd, err := BootstrapCommand(BootstrapOptions{
+		NodeName:     "web01",
+		ServerURL:    "https://cinc.example.test/organizations/acme",
+		ClientKeyPEM: "PRIVATE KEY",
+	})
+	if err != nil {
+		t.Fatalf("BootstrapCommand: %v", err)
+	}
+	if !strings.Contains(cmd, "trap") || !strings.Contains(cmd, "rm -f") {
+		t.Errorf("script should remove the downloaded installer on exit:\n%s", cmd)
+	}
+}
+
 // firstBoot extracts and decodes the first-boot.json payload embedded in the
 // generated bootstrap script so tests can assert on the actual JSON keys.
 func firstBoot(t *testing.T, opts BootstrapOptions) map[string]any {