1 files changed, 68 insertions, 0 deletions
diff --git a/test/syscalls/linux/pty_root.cc b/test/syscalls/linux/pty_root.cc
new file mode 100644
index 000000000..14a4af980
--- /dev/null
+++ b/test/syscalls/linux/pty_root.cc
@@ -0,0 +1,68 @@
+// Copyright 2018 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <sys/ioctl.h>
+#include <termios.h>
+
+#include "gtest/gtest.h"
+#include "absl/base/macros.h"
+#include "test/util/capability_util.h"
+#include "test/util/file_descriptor.h"
+#include "test/util/posix_error.h"
+#include "test/util/pty_util.h"
+
+namespace gvisor {
+namespace testing {
+
+// These tests should be run as root.
+namespace {
+
+TEST(JobControlRootTest, StealTTY) {
+  SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_SYS_ADMIN)));
+
+  // Make this a session leader, which also drops the controlling terminal.
+  // In the gVisor test environment, this test will be run as the session
+  // leader already (as the sentry init process).
+  if (!IsRunningOnGvisor()) {
+    ASSERT_THAT(setsid(), SyscallSucceeds());
+  }
+
+  FileDescriptor master =
+      ASSERT_NO_ERRNO_AND_VALUE(Open("/dev/ptmx", O_RDWR | O_NONBLOCK));
+  FileDescriptor slave = ASSERT_NO_ERRNO_AND_VALUE(OpenSlave(master));
+
+  // Make slave the controlling terminal.
+  ASSERT_THAT(ioctl(slave.get(), TIOCSCTTY, 0), SyscallSucceeds());
+
+  // Fork, join a new session, and try to steal the parent's controlling
+  // terminal, which should succeed when we have CAP_SYS_ADMIN and pass an arg
+  // of 1.
+  pid_t child = fork();
+  if (!child) {
+    ASSERT_THAT(setsid(), SyscallSucceeds());
+    // We shouldn't be able to steal the terminal with the wrong arg value.
+    TEST_PCHECK(ioctl(slave.get(), TIOCSCTTY, 0));
+    // We should be able to steal it here.
+    TEST_PCHECK(!ioctl(slave.get(), TIOCSCTTY, 1));
+    _exit(0);
+  }
+
+  int wstatus;
+  ASSERT_THAT(waitpid(child, &wstatus, 0), SyscallSucceedsWithValue(child));
+  ASSERT_EQ(wstatus, 0);
+}
+
+}  // namespace
+}  // namespace testing
+}  // namespace gvisor