Add verity getdents tests

PiperOrigin-RevId: 376001603

pkg/sentry/fsimpl/verity/verity.go

@@ -868,6 +868,10 @@ func (fd *fileDescription) IterDirents(ctx context.Context, cb vfs.IterDirentsCa
 	fd.mu.Lock()
 	defer fd.mu.Unlock()
 
+	if _, err := fd.lowerFD.Seek(ctx, fd.off, linux.SEEK_SET); err != nil {
+		return err
+	}
+
 	var ds []vfs.Dirent
 	err := fd.lowerFD.IterDirents(ctx, vfs.IterDirentsCallbackFunc(func(dirent vfs.Dirent) error {
 		// Do not include the Merkle tree files.
@@ -890,8 +894,8 @@ func (fd *fileDescription) IterDirents(ctx context.Context, cb vfs.IterDirentsCa
 		return err
 	}
 
-	// The result should contain all children plus "." and "..".
-	if fd.d.verityEnabled() && len(ds) != len(fd.d.childrenNames)+2 {
+	// The result should be a part of all children plus "." and "..", counting from fd.off.
+	if fd.d.verityEnabled() && len(ds) != len(fd.d.childrenNames)+2-int(fd.off) {
 		return fd.d.fs.alertIntegrityViolation(fmt.Sprintf("Unexpected children number %d", len(ds)))
 	}
 

test/syscalls/BUILD

@@ -215,6 +215,10 @@ syscall_test(
     test = "//test/syscalls/linux:getdents_test",
 )
 
+syscall_test(
+    test = "//test/syscalls/linux:verity_getdents_test",
+)
+
 syscall_test(
     test = "//test/syscalls/linux:getrandom_test",
 )

test/syscalls/linux/BUILD

@@ -961,6 +961,22 @@ cc_binary(
     ],
 )
 
+cc_binary(
+    name = "verity_getdents_test",
+    testonly = 1,
+    srcs = ["verity_getdents.cc"],
+    linkstatic = 1,
+    deps = [
+        "//test/util:capability_util",
+        gtest,
+        "//test/util:fs_util",
+        "//test/util:temp_path",
+        "//test/util:test_main",
+        "//test/util:test_util",
+        "//test/util:verity_util",
+    ],
+)
+
 cc_binary(
     name = "getrandom_test",
     testonly = 1,

test/syscalls/linux/verity_getdents.cc

@@ -0,0 +1,95 @@
+// Copyright 2021 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 <dirent.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <sys/mount.h>
+#include <sys/syscall.h>
+
+#include <string>
+#include <vector>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "test/util/capability_util.h"
+#include "test/util/fs_util.h"
+#include "test/util/temp_path.h"
+#include "test/util/test_util.h"
+#include "test/util/verity_util.h"
+
+namespace gvisor {
+namespace testing {
+
+namespace {
+
+class GetDentsTest : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    // Verity is implemented in VFS2.
+    SKIP_IF(IsRunningWithVFS1());
+
+    SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_SYS_ADMIN)));
+    // Mount a tmpfs file system, to be wrapped by a verity fs.
+    tmpfs_dir_ = ASSERT_NO_ERRNO_AND_VALUE(TempPath::CreateDir());
+    ASSERT_THAT(mount("", tmpfs_dir_.path().c_str(), "tmpfs", 0, ""),
+                SyscallSucceeds());
+
+    // Create a new file in the tmpfs mount.
+    file_ = ASSERT_NO_ERRNO_AND_VALUE(
+        TempPath::CreateFileWith(tmpfs_dir_.path(), kContents, 0777));
+    filename_ = Basename(file_.path());
+  }
+
+  TempPath tmpfs_dir_;
+  TempPath file_;
+  std::string filename_;
+};
+
+TEST_F(GetDentsTest, GetDents) {
+  std::string verity_dir =
+      ASSERT_NO_ERRNO_AND_VALUE(MountVerity(tmpfs_dir_.path(), filename_));
+
+  std::vector<std::string> expect = {".", "..", filename_};
+  EXPECT_NO_ERRNO(DirContains(verity_dir, expect, /*exclude=*/{}));
+}
+
+TEST_F(GetDentsTest, Deleted) {
+  std::string verity_dir =
+      ASSERT_NO_ERRNO_AND_VALUE(MountVerity(tmpfs_dir_.path(), filename_));
+
+  EXPECT_THAT(unlink(JoinPath(tmpfs_dir_.path(), filename_).c_str()),
+              SyscallSucceeds());
+
+  EXPECT_THAT(DirContains(verity_dir, /*expect=*/{}, /*exclude=*/{}),
+              PosixErrorIs(EIO, ::testing::_));
+}
+
+TEST_F(GetDentsTest, Renamed) {
+  std::string verity_dir =
+      ASSERT_NO_ERRNO_AND_VALUE(MountVerity(tmpfs_dir_.path(), filename_));
+
+  std::string new_file_name = "renamed-" + filename_;
+  EXPECT_THAT(rename(JoinPath(tmpfs_dir_.path(), filename_).c_str(),
+                     JoinPath(tmpfs_dir_.path(), new_file_name).c_str()),
+              SyscallSucceeds());
+
+  EXPECT_THAT(DirContains(verity_dir, /*expect=*/{}, /*exclude=*/{}),
+              PosixErrorIs(EIO, ::testing::_));
+}
+
+}  // namespace
+
+}  // namespace testing
+}  // namespace gvisor