1 files changed, 48 insertions, 0 deletions
diff --git a/test/syscalls/linux/arch_prctl.cc b/test/syscalls/linux/arch_prctl.cc
new file mode 100644
index 000000000..5687ceb86
--- /dev/null
+++ b/test/syscalls/linux/arch_prctl.cc
@@ -0,0 +1,48 @@
+// Copyright 2018 Google LLC
+//
+// 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 <asm/prctl.h>
+#include <sys/prctl.h>
+
+#include "gtest/gtest.h"
+#include "test/util/test_util.h"
+
+// glibc does not provide a prototype for arch_prctl() so declare it here.
+extern "C" int arch_prctl(int code, uintptr_t addr);
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+TEST(ArchPrctlTest, GetSetFS) {
+  uintptr_t orig;
+  const uintptr_t kNonCanonicalFsbase = 0x4141414142424242;
+
+  // Get the original FS.base and then set it to the same value (this is
+  // intentional because FS.base is the TLS pointer so we cannot change it
+  // arbitrarily).
+  ASSERT_THAT(arch_prctl(ARCH_GET_FS, reinterpret_cast<uintptr_t>(&orig)),
+              SyscallSucceeds());
+  ASSERT_THAT(arch_prctl(ARCH_SET_FS, orig), SyscallSucceeds());
+
+  // Trying to set FS.base to a non-canonical value should return an error.
+  ASSERT_THAT(arch_prctl(ARCH_SET_FS, kNonCanonicalFsbase),
+              SyscallFailsWithErrno(EPERM));
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor