Open source system call tests.

PiperOrigin-RevId: 224886231
Change-Id: I0fccb4d994601739d8b16b1d4e6b31f40297fb22

1 files changed, 101 insertions, 0 deletions

diff --git a/test/util/capability_util.h b/test/util/capability_util.h
new file mode 100644
index 000000000..8708f5e69
--- /dev/null
+++ b/test/util/capability_util.h
@@ -0,0 +1,101 @@
+// 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.
+
+// Utilities for testing capabilties.
+
+#ifndef GVISOR_TEST_UTIL_CAPABILITY_UTIL_H_
+#define GVISOR_TEST_UTIL_CAPABILITY_UTIL_H_
+
+#include <errno.h>
+#include <linux/capability.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+#include "test/util/cleanup.h"
+#include "test/util/posix_error.h"
+#include "test/util/save_util.h"
+#include "test/util/test_util.h"
+
+#ifndef _LINUX_CAPABILITY_VERSION_3
+#error Expecting _LINUX_CAPABILITY_VERSION_3 support
+#endif
+
+namespace gvisor {
+namespace testing {
+
+// HaveCapability returns true if the process has the specified EFFECTIVE
+// capability.
+inline PosixErrorOr<bool> HaveCapability(int cap) {
+  if (!cap_valid(cap)) {
+    return PosixError(EINVAL, "Invalid capability");
+  }
+
+  struct __user_cap_header_struct header = {_LINUX_CAPABILITY_VERSION_3, 0};
+  struct __user_cap_data_struct caps[_LINUX_CAPABILITY_U32S_3] = {};
+  RETURN_ERROR_IF_SYSCALL_FAIL(syscall(__NR_capget, &header, &caps));
+  MaybeSave();
+
+  return (caps[CAP_TO_INDEX(cap)].effective & CAP_TO_MASK(cap)) != 0;
+}
+
+// SetCapability sets the specified EFFECTIVE capability.
+inline PosixError SetCapability(int cap, bool set) {
+  if (!cap_valid(cap)) {
+    return PosixError(EINVAL, "Invalid capability");
+  }
+
+  struct __user_cap_header_struct header = {_LINUX_CAPABILITY_VERSION_3, 0};
+  struct __user_cap_data_struct caps[_LINUX_CAPABILITY_U32S_3] = {};
+  RETURN_ERROR_IF_SYSCALL_FAIL(syscall(__NR_capget, &header, &caps));
+  MaybeSave();
+
+  if (set) {
+    caps[CAP_TO_INDEX(cap)].effective |= CAP_TO_MASK(cap);
+  } else {
+    caps[CAP_TO_INDEX(cap)].effective &= ~CAP_TO_MASK(cap);
+  }
+  header = {_LINUX_CAPABILITY_VERSION_3, 0};
+  RETURN_ERROR_IF_SYSCALL_FAIL(syscall(__NR_capset, &header, &caps));
+  MaybeSave();
+
+  return NoError();
+}
+
+// DropPermittedCapability drops the specified PERMITTED. The EFFECTIVE
+// capabilities must be a subset of PERMITTED, so those are dropped as well.
+inline PosixError DropPermittedCapability(int cap) {
+  if (!cap_valid(cap)) {
+    return PosixError(EINVAL, "Invalid capability");
+  }
+
+  struct __user_cap_header_struct header = {_LINUX_CAPABILITY_VERSION_3, 0};
+  struct __user_cap_data_struct caps[_LINUX_CAPABILITY_U32S_3] = {};
+  RETURN_ERROR_IF_SYSCALL_FAIL(syscall(__NR_capget, &header, &caps));
+  MaybeSave();
+
+  caps[CAP_TO_INDEX(cap)].effective &= ~CAP_TO_MASK(cap);
+  caps[CAP_TO_INDEX(cap)].permitted &= ~CAP_TO_MASK(cap);
+
+  header = {_LINUX_CAPABILITY_VERSION_3, 0};
+  RETURN_ERROR_IF_SYSCALL_FAIL(syscall(__NR_capset, &header, &caps));
+  MaybeSave();
+
+  return NoError();
+}
+
+PosixErrorOr<bool> CanCreateUserNamespace();
+
+}  // namespace testing
+}  // namespace gvisor
+#endif  // GVISOR_TEST_UTIL_CAPABILITY_UTIL_H_