sandbox: Extend BrokerPolicy to support file creation

sandbox/linux/syscall_broker/broker_file_permission_unittest.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "sandbox/linux/syscall_broker/broker_file_permission.h"
+
+#include <fcntl.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "base/logging.h"
+#include "sandbox/linux/tests/test_utils.h"
+#include "sandbox/linux/tests/unit_tests.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace sandbox {
+
+namespace syscall_broker {
+
+class BrokerFilePermissionTester {
+ public:
+  static bool ValidatePath(const char* path) {
+    return BrokerFilePermission::ValidatePath(path);
+  }
+  static const char* GetErrorMessage() {
+    return BrokerFilePermission::GetErrorMessageForTests();
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(BrokerFilePermissionTester);
+};
+
+namespace {
+
+// Creation tests are DEATH tests as a bad permission causes termination.
+SANDBOX_TEST(BrokerFilePermission, CreateGood) {
+  const char kPath[] = "/tmp/good";
+  BrokerFilePermission perm = BrokerFilePermission::ReadOnly(kPath);
+}
+
+SANDBOX_TEST(BrokerFilePermission, CreateGoodRecursive) {
+  const char kPath[] = "/tmp/good/";
+  BrokerFilePermission perm = BrokerFilePermission::ReadOnlyRecursive(kPath);
+}
+
+SANDBOX_DEATH_TEST(
+    BrokerFilePermission,
+    CreateBad,
+    DEATH_MESSAGE(BrokerFilePermissionTester::GetErrorMessage())) {
+  const char kPath[] = "/tmp/bad/";
+  BrokerFilePermission perm = BrokerFilePermission::ReadOnly(kPath);
+}
+
+SANDBOX_DEATH_TEST(
+    BrokerFilePermission,
+    CreateBadRecursive,
+    DEATH_MESSAGE(BrokerFilePermissionTester::GetErrorMessage())) {
+  const char kPath[] = "/tmp/bad";
+  BrokerFilePermission perm = BrokerFilePermission::ReadOnlyRecursive(kPath);
+}
+
+SANDBOX_DEATH_TEST(
+    BrokerFilePermission,
+    CreateBadNotAbs,
+    DEATH_MESSAGE(BrokerFilePermissionTester::GetErrorMessage())) {
+  const char kPath[] = "tmp/bad";
+  BrokerFilePermission perm = BrokerFilePermission::ReadOnly(kPath);
+}
+
+SANDBOX_DEATH_TEST(
+    BrokerFilePermission,
+    CreateBadEmpty,
+    DEATH_MESSAGE(BrokerFilePermissionTester::GetErrorMessage())) {
+  const char kPath[] = "";
+  BrokerFilePermission perm = BrokerFilePermission::ReadOnly(kPath);
+}
+
+// CheckPerm tests |path| against |perm| given |access_flags|.
+// If |create| is true then file creation is tested for success.
+void CheckPerm(const BrokerFilePermission& perm,
+               const char* path,
+               int access_flags,
+               bool create) {
+  const char* file_to_open = NULL;
+
+  ASSERT_FALSE(perm.CheckAccess(path, X_OK, NULL));
+  ASSERT_TRUE(perm.CheckAccess(path, F_OK, NULL));
+  // check bad perms
+  switch (access_flags) {
+    case O_RDONLY:
+      ASSERT_TRUE(perm.CheckOpen(path, O_RDONLY, &file_to_open, NULL));
+      ASSERT_FALSE(perm.CheckOpen(path, O_WRONLY, &file_to_open, NULL));
+      ASSERT_FALSE(perm.CheckOpen(path, O_RDWR, &file_to_open, NULL));
+      ASSERT_TRUE(perm.CheckAccess(path, R_OK, NULL));
+      ASSERT_FALSE(perm.CheckAccess(path, W_OK, NULL));
+      break;
+    case O_WRONLY:
+      ASSERT_FALSE(perm.CheckOpen(path, O_RDONLY, &file_to_open, NULL));
+      ASSERT_TRUE(perm.CheckOpen(path, O_WRONLY, &file_to_open, NULL));
+      ASSERT_FALSE(perm.CheckOpen(path, O_RDWR, &file_to_open, NULL));
+      ASSERT_FALSE(perm.CheckAccess(path, R_OK, NULL));
+      ASSERT_TRUE(perm.CheckAccess(path, W_OK, NULL));
+      break;
+    case O_RDWR:
+      ASSERT_TRUE(perm.CheckOpen(path, O_RDONLY, &file_to_open, NULL));
+      ASSERT_TRUE(perm.CheckOpen(path, O_WRONLY, &file_to_open, NULL));
+      ASSERT_TRUE(perm.CheckOpen(path, O_RDWR, &file_to_open, NULL));
+      ASSERT_TRUE(perm.CheckAccess(path, R_OK, NULL));
+      ASSERT_TRUE(perm.CheckAccess(path, W_OK, NULL));
+      break;
+    default:
+      // Bad test case
+      NOTREACHED();
+  }
+
+// O_SYNC can be defined as (__O_SYNC|O_DSYNC)
+#ifdef O_DSYNC
+  const int kSyncFlag = O_SYNC & ~O_DSYNC;
+#else
+  const int kSyncFlag = O_SYNC;
+#endif
+
+  // check every possible flag and act accordingly.
+  for (int i = 2; i < 32; i++) {
+    int flag = 1 << i;
+    switch (flag) {
+      case O_APPEND:
+      case O_ASYNC:
+      case O_DIRECT:
+      case O_DIRECTORY:
+#ifdef O_DSYNC
+      case O_DSYNC:
+#endif
+      case O_EXCL:
+      case O_LARGEFILE:
+      case O_NOATIME:
+      case O_NOCTTY:
+      case O_NOFOLLOW:
+      case O_NONBLOCK:
+#if (O_NONBLOCK != O_NDELAY)
+      case O_NDELAY:
+#endif
+      case kSyncFlag:
+      case O_TRUNC:
+        ASSERT_TRUE(
+            perm.CheckOpen(path, access_flags | flag, &file_to_open, NULL));
+        break;
+      case O_CLOEXEC:
+      case O_CREAT:
+      default:
+        ASSERT_FALSE(
+            perm.CheckOpen(path, access_flags | flag, &file_to_open, NULL));
+    }
+  }
+  if (create) {
+    bool unlink;
+    ASSERT_TRUE(perm.CheckOpen(path, O_CREAT | O_EXCL | access_flags,
+                               &file_to_open, &unlink));
+    ASSERT_FALSE(unlink);
+  } else {
+    ASSERT_FALSE(perm.CheckOpen(path, O_CREAT | O_EXCL | access_flags,
+                                &file_to_open, NULL));
+  }
+}
+
+TEST(BrokerFilePermission, ReadOnly) {
+  const char kPath[] = "/tmp/good";
+  BrokerFilePermission perm = BrokerFilePermission::ReadOnly(kPath);
+  CheckPerm(perm, kPath, O_RDONLY, false);  // CheckPerm must be last

[jln (very slow on Chromium), 2014/11/26 19:49:06]

Explain why: "For ASSERT* to successfully exit the test." (Also don't forget the
final dot in comments).

You can also reuse the comment used in other tests (put after the call to the
subfunction):

// Don't do anything here, so that ASSERT works in the subfunction as
// expected.

+}
+
+TEST(BrokerFilePermission, ReadOnlyRecursive) {
+  const char kPath[] = "/tmp/good/";
+  const char kPathFile[] = "/tmp/good/file";
+  BrokerFilePermission perm = BrokerFilePermission::ReadOnlyRecursive(kPath);
+  CheckPerm(perm, kPathFile, O_RDONLY, false);  // CheckPerm must be last
+}
+
+TEST(BrokerFilePermission, WriteOnly) {
+  const char kPath[] = "/tmp/good";
+  BrokerFilePermission perm = BrokerFilePermission::WriteOnly(kPath);
+  CheckPerm(perm, kPath, O_WRONLY, false);  // CheckPerm must be last
+}
+
+TEST(BrokerFilePermission, ReadWrite) {
+  const char kPath[] = "/tmp/good";
+  BrokerFilePermission perm = BrokerFilePermission::ReadWrite(kPath);
+  CheckPerm(perm, kPath, O_RDWR, false);  // CheckPerm must be last
+}
+
+TEST(BrokerFilePermission, ReadWriteCreate) {
+  const char kPath[] = "/tmp/good";
+  BrokerFilePermission perm = BrokerFilePermission::ReadWriteCreate(kPath);
+  CheckPerm(perm, kPath, O_RDWR, true);  // CheckPerm must be last
+}
+
+void CheckUnlink(BrokerFilePermission& perm,
+                 const char* path,
+                 int access_flags) {
+  bool unlink;
+  ASSERT_FALSE(perm.CheckOpen(path, access_flags, NULL, &unlink));
+  ASSERT_FALSE(perm.CheckOpen(path, access_flags | O_CREAT, NULL, &unlink));
+  ASSERT_TRUE(
+      perm.CheckOpen(path, access_flags | O_CREAT | O_EXCL, NULL, &unlink));
+  ASSERT_TRUE(unlink);
+}
+
+TEST(BrokerFilePermission, ReadWriteCreateUnlink) {
+  const char kPath[] = "/tmp/good";
+  BrokerFilePermission perm =
+      BrokerFilePermission::ReadWriteCreateUnlink(kPath);
+  CheckUnlink(perm, kPath, O_RDWR);  // CheckUnlink must be last
+}
+
+TEST(BrokerFilePermission, ReadWriteCreateUnlinkRecursive) {
+  const char kPath[] = "/tmp/good/";
+  const char kPathFile[] = "/tmp/good/file";
+  BrokerFilePermission perm =
+      BrokerFilePermission::ReadWriteCreateUnlinkRecursive(kPath);
+  CheckUnlink(perm, kPathFile, O_RDWR);  // CheckUnlink must be last
+}
+
+TEST(BrokerFilePermission, ValidatePath) {
+  EXPECT_TRUE(BrokerFilePermissionTester::ValidatePath("/path"));
+  EXPECT_TRUE(BrokerFilePermissionTester::ValidatePath("/"));
+  EXPECT_TRUE(BrokerFilePermissionTester::ValidatePath("/..path"));
+
+  EXPECT_FALSE(BrokerFilePermissionTester::ValidatePath(""));
+  EXPECT_FALSE(BrokerFilePermissionTester::ValidatePath("bad"));
+  EXPECT_FALSE(BrokerFilePermissionTester::ValidatePath("/bad/"));
+  EXPECT_FALSE(BrokerFilePermissionTester::ValidatePath("bad/"));
+  EXPECT_FALSE(BrokerFilePermissionTester::ValidatePath("/bad/.."));
+  EXPECT_FALSE(BrokerFilePermissionTester::ValidatePath("/bad/../bad"));
+  EXPECT_FALSE(BrokerFilePermissionTester::ValidatePath("/../bad"));
+}
+
+}  // namespace
+
+}  // namespace syscall_broker
+
+}  // namespace sandbox