Update from chromium 62675d9fb31fb8cedc40f68e78e8445a74f362e7

sandbox/linux/services/credentials_unittest.cc

+// Copyright (c) 2012 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/services/credentials.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "base/files/file_util.h"
+#include "base/files/scoped_file.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "sandbox/linux/tests/unit_tests.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace sandbox {
+
+namespace {
+
+bool DirectoryExists(const char* path) {
+  struct stat dir;
+  errno = 0;
+  int ret = stat(path, &dir);
+  return -1 != ret || ENOENT != errno;
+}
+
+bool WorkingDirectoryIsRoot() {
+  char current_dir[PATH_MAX];
+  char* cwd = getcwd(current_dir, sizeof(current_dir));
+  PCHECK(cwd);
+  if (strcmp("/", cwd)) return false;
+
+  // The current directory is the root. Add a few paranoid checks.
+  struct stat current;
+  CHECK_EQ(0, stat(".", &current));
+  struct stat parrent;
+  CHECK_EQ(0, stat("..", &parrent));
+  CHECK_EQ(current.st_dev, parrent.st_dev);
+  CHECK_EQ(current.st_ino, parrent.st_ino);
+  CHECK_EQ(current.st_mode, parrent.st_mode);
+  CHECK_EQ(current.st_uid, parrent.st_uid);
+  CHECK_EQ(current.st_gid, parrent.st_gid);
+  return true;
+}
+
+// Give dynamic tools a simple thing to test.
+TEST(Credentials, CreateAndDestroy) {
+  {
+    Credentials cred1;
+    (void) cred1;
+  }
+  scoped_ptr<Credentials> cred2(new Credentials);
+}
+
+TEST(Credentials, CountOpenFds) {
+  base::ScopedFD proc_fd(open("/proc", O_RDONLY | O_DIRECTORY));
+  ASSERT_TRUE(proc_fd.is_valid());
+  Credentials creds;
+  int fd_count = creds.CountOpenFds(proc_fd.get());
+  int fd = open("/dev/null", O_RDONLY);
+  ASSERT_LE(0, fd);
+  EXPECT_EQ(fd_count + 1, creds.CountOpenFds(proc_fd.get()));
+  ASSERT_EQ(0, IGNORE_EINTR(close(fd)));
+  EXPECT_EQ(fd_count, creds.CountOpenFds(proc_fd.get()));
+}
+
+TEST(Credentials, HasOpenDirectory) {
+  Credentials creds;
+  // No open directory should exist at startup.
+  EXPECT_FALSE(creds.HasOpenDirectory(-1));
+  {
+    // Have a "/dev" file descriptor around.
+    int dev_fd = open("/dev", O_RDONLY | O_DIRECTORY);
+    base::ScopedFD dev_fd_closer(dev_fd);
+    EXPECT_TRUE(creds.HasOpenDirectory(-1));
+  }
+  EXPECT_FALSE(creds.HasOpenDirectory(-1));
+}
+
+TEST(Credentials, HasOpenDirectoryWithFD) {
+  Credentials creds;
+
+  int proc_fd = open("/proc", O_RDONLY | O_DIRECTORY);
+  base::ScopedFD proc_fd_closer(proc_fd);
+  ASSERT_LE(0, proc_fd);
+
+  // Don't pass |proc_fd|, an open directory (proc_fd) should
+  // be detected.
+  EXPECT_TRUE(creds.HasOpenDirectory(-1));
+  // Pass |proc_fd| and no open directory should be detected.
+  EXPECT_FALSE(creds.HasOpenDirectory(proc_fd));
+
+  {
+    // Have a "/dev" file descriptor around.
+    int dev_fd = open("/dev", O_RDONLY | O_DIRECTORY);
+    base::ScopedFD dev_fd_closer(dev_fd);
+    EXPECT_TRUE(creds.HasOpenDirectory(proc_fd));
+  }
+
+  // The "/dev" file descriptor should now be closed, |proc_fd| is the only
+  // directory file descriptor open.
+  EXPECT_FALSE(creds.HasOpenDirectory(proc_fd));
+}
+
+SANDBOX_TEST(Credentials, DropAllCaps) {
+  Credentials creds;
+  CHECK(creds.DropAllCapabilities());
+  CHECK(!creds.HasAnyCapability());
+}
+
+SANDBOX_TEST(Credentials, GetCurrentCapString) {
+  Credentials creds;
+  CHECK(creds.DropAllCapabilities());
+  const char kNoCapabilityText[] = "=";
+  CHECK(*creds.GetCurrentCapString() == kNoCapabilityText);
+}
+
+SANDBOX_TEST(Credentials, MoveToNewUserNS) {
+  Credentials creds;
+  creds.DropAllCapabilities();
+  bool moved_to_new_ns = creds.MoveToNewUserNS();
+  fprintf(stdout,
+          "Unprivileged CLONE_NEWUSER supported: %s\n",
+          moved_to_new_ns ? "true." : "false.");
+  fflush(stdout);
+  if (!moved_to_new_ns) {
+    fprintf(stdout, "This kernel does not support unprivileged namespaces. "
+            "USERNS tests will succeed without running.\n");
+    fflush(stdout);
+    return;
+  }
+  CHECK(creds.HasAnyCapability());
+  creds.DropAllCapabilities();
+  CHECK(!creds.HasAnyCapability());
+}
+
+SANDBOX_TEST(Credentials, SupportsUserNS) {
+  Credentials creds;
+  creds.DropAllCapabilities();
+  bool user_ns_supported = Credentials::SupportsNewUserNS();
+  bool moved_to_new_ns = creds.MoveToNewUserNS();
+  CHECK_EQ(user_ns_supported, moved_to_new_ns);
+}
+
+SANDBOX_TEST(Credentials, UidIsPreserved) {
+  Credentials creds;
+  creds.DropAllCapabilities();
+  uid_t old_ruid, old_euid, old_suid;
+  gid_t old_rgid, old_egid, old_sgid;
+  PCHECK(0 == getresuid(&old_ruid, &old_euid, &old_suid));
+  PCHECK(0 == getresgid(&old_rgid, &old_egid, &old_sgid));
+  // Probably missing kernel support.
+  if (!creds.MoveToNewUserNS()) return;
+  uid_t new_ruid, new_euid, new_suid;
+  PCHECK(0 == getresuid(&new_ruid, &new_euid, &new_suid));
+  CHECK(old_ruid == new_ruid);
+  CHECK(old_euid == new_euid);
+  CHECK(old_suid == new_suid);
+
+  gid_t new_rgid, new_egid, new_sgid;
+  PCHECK(0 == getresgid(&new_rgid, &new_egid, &new_sgid));
+  CHECK(old_rgid == new_rgid);
+  CHECK(old_egid == new_egid);
+  CHECK(old_sgid == new_sgid);
+}
+
+bool NewUserNSCycle(Credentials* creds) {
+  DCHECK(creds);
+  if (!creds->MoveToNewUserNS() ||
+      !creds->HasAnyCapability() ||
+      !creds->DropAllCapabilities() ||
+      creds->HasAnyCapability()) {
+    return false;
+  }
+  return true;
+}
+
+SANDBOX_TEST(Credentials, NestedUserNS) {
+  Credentials creds;
+  CHECK(creds.DropAllCapabilities());
+  // Probably missing kernel support.
+  if (!creds.MoveToNewUserNS()) return;
+  creds.DropAllCapabilities();
+  // As of 3.12, the kernel has a limit of 32. See create_user_ns().
+  const int kNestLevel = 10;
+  for (int i = 0; i < kNestLevel; ++i) {
+    CHECK(NewUserNSCycle(&creds)) << "Creating new user NS failed at iteration "
+                                  << i << ".";
+  }
+}
+
+// Test the WorkingDirectoryIsRoot() helper.
+TEST(Credentials, CanDetectRoot) {
+  ASSERT_EQ(0, chdir("/proc/"));
+  ASSERT_FALSE(WorkingDirectoryIsRoot());
+  ASSERT_EQ(0, chdir("/"));
+  ASSERT_TRUE(WorkingDirectoryIsRoot());
+}
+
+SANDBOX_TEST(Credentials, DISABLE_ON_LSAN(DropFileSystemAccessIsSafe)) {
+  Credentials creds;
+  CHECK(creds.DropAllCapabilities());
+  // Probably missing kernel support.
+  if (!creds.MoveToNewUserNS()) return;
+  CHECK(creds.DropFileSystemAccess());
+  CHECK(!DirectoryExists("/proc"));
+  CHECK(WorkingDirectoryIsRoot());
+  // We want the chroot to never have a subdirectory. A subdirectory
+  // could allow a chroot escape.
+  CHECK_NE(0, mkdir("/test", 0700));
+}
+
+// Check that after dropping filesystem access and dropping privileges
+// it is not possible to regain capabilities.
+SANDBOX_TEST(Credentials, DISABLE_ON_LSAN(CannotRegainPrivileges)) {
+  Credentials creds;
+  CHECK(creds.DropAllCapabilities());
+  // Probably missing kernel support.
+  if (!creds.MoveToNewUserNS()) return;
+  CHECK(creds.DropFileSystemAccess());
+  CHECK(creds.DropAllCapabilities());
+
+  // The kernel should now prevent us from regaining capabilities because we
+  // are in a chroot.
+  CHECK(!Credentials::SupportsNewUserNS());
+  CHECK(!creds.MoveToNewUserNS());
+}
+
+}  // namespace.
+
+}  // namespace sandbox.