win,fs: get (most) fstat when no permission (#4566)

Replaces: https://github.com/libuv/libuv/pull/4504
Fixes: https://github.com/libuv/libuv/issues/1980
Fixes: https://github.com/libuv/libuv/issues/3267

Co-authored-by: Hüseyin Açacak <huseyin@janeasystems.com>

src/win/fs.c

@@ -58,6 +58,19 @@
 #define FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE  0x0010
 #endif  /* FILE_DISPOSITION_IGNORE_READONLY_ATTRIBUTE */
 
+NTSTATUS uv__RtlUnicodeStringInit(
+  PUNICODE_STRING DestinationString,
+  PWSTR SourceString,
+  size_t SourceStringLen
+) {
+  if (SourceStringLen > 0x7FFF)
+    return STATUS_INVALID_PARAMETER;
+  DestinationString->MaximumLength = DestinationString->Length =
+    SourceStringLen * sizeof(SourceString[0]);
+  DestinationString->Buffer = SourceString;
+  return STATUS_SUCCESS;
+}
+
 #define INIT(subtype)                                                         \
   do {                                                                        \
     if (req == NULL)                                                          \
@@ -1689,12 +1702,12 @@ INLINE static fs__stat_path_return_t fs__stat_path(WCHAR* path,
     uv_stat_t* statbuf, int do_lstat) {
   FILE_STAT_BASIC_INFORMATION stat_info;
 
-  // Check if the new fast API is available.
+  /* Check if the new fast API is available. */
   if (!pGetFileInformationByName) {
     return FS__STAT_PATH_TRY_SLOW;
   }
 
-  // Check if the API call fails.
+  /* Check if the API call fails. */
   if (!pGetFileInformationByName(path, FileStatBasicByNameInfo, &stat_info,
       sizeof(stat_info))) {
     switch(GetLastError()) {
@@ -1708,7 +1721,7 @@ INLINE static fs__stat_path_return_t fs__stat_path(WCHAR* path,
     return FS__STAT_PATH_TRY_SLOW;
   }
 
-  // A file handle is needed to get st_size for links.
+  /* A file handle is needed to get st_size for links. */
   if ((stat_info.FileAttributes & FILE_ATTRIBUTE_REPARSE_POINT)) {
     return FS__STAT_PATH_TRY_SLOW;
   }
@@ -1802,7 +1815,6 @@ INLINE static int fs__stat_handle(HANDLE handle, uv_stat_t* statbuf,
      * detect this failure and retry without do_lstat if appropriate.
      */
     if (fs__readlink_handle(handle, NULL, &target_length) != 0) {
-      fs__stat_assign_statbuf(statbuf, stat_info, do_lstat);
       return -1;
     }
     stat_info.EndOfFile.QuadPart = target_length;
@@ -1941,6 +1953,179 @@ INLINE static void fs__stat_prepare_path(WCHAR* pathw) {
   }
 }
 
+INLINE static DWORD fs__stat_directory(WCHAR* path, uv_stat_t* statbuf,
+    int do_lstat, DWORD ret_error) {
+  HANDLE handle = INVALID_HANDLE_VALUE;
+  FILE_STAT_BASIC_INFORMATION stat_info;
+  FILE_ID_FULL_DIR_INFORMATION dir_info;
+  FILE_FS_VOLUME_INFORMATION volume_info;
+  FILE_FS_DEVICE_INFORMATION device_info;
+  IO_STATUS_BLOCK io_status;
+  NTSTATUS nt_status;
+  WCHAR* path_dirpath = NULL;
+  WCHAR* path_filename = NULL;
+  UNICODE_STRING FileMask;
+  size_t len;
+  size_t split;
+  WCHAR splitchar;
+  int includes_name;
+
+  /* AKA strtok or wcscspn, in reverse. */
+  len = wcslen(path);
+  split = len;
+
+  includes_name = 0;
+  while (split > 0 && path[split - 1] != L'\\' && path[split - 1] != L'/' &&
+                      path[split - 1] != L':') {
+    /* check if the path contains a character other than /,\,:,. */
+    if (path[split-1] != '.') {
+      includes_name = 1;
+    }
+    split--;
+  }
+  /* If the path is a relative path with a file name or a folder name */
+  if (split == 0 && includes_name) {
+    path_dirpath = L".";
+  /* If there is a slash or a backslash */
+  } else if (path[split - 1] == L'\\' || path[split - 1] == L'/') {
+    path_dirpath = path;
+    /* If there is no filename, consider it as a relative folder path */
+    if (!includes_name) {
+      split = len;
+    /* Else, split it */
+    } else {
+      splitchar = path[split - 1];
+      path[split - 1] = L'\0';
+    }
+  /* e.g. "..", "c:" */
+  } else {
+    path_dirpath = path;
+    split = len;
+  }
+  path_filename = &path[split];
+
+  len = 0;
+  while (1) {
+    if (path_filename[len] == L'\0')
+      break;
+    if (path_filename[len] == L'*' || path_filename[len] == L'?' ||
+        path_filename[len] == L'>' || path_filename[len] == L'<' ||
+        path_filename[len] == L'"') {
+      ret_error = ERROR_INVALID_NAME;
+      goto cleanup;
+    }
+    len++;
+  }
+
+  /* Get directory handle */
+  handle = CreateFileW(path_dirpath,
+                       FILE_LIST_DIRECTORY,
+                       FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                       NULL,
+                       OPEN_EXISTING,
+                       FILE_FLAG_BACKUP_SEMANTICS,
+                       NULL);
+
+  if (handle == INVALID_HANDLE_VALUE) {
+    ret_error = GetLastError();
+    goto cleanup;
+  }
+
+  /* Get files in the directory */
+  nt_status = uv__RtlUnicodeStringInit(&FileMask, path_filename, len);
+  if (!NT_SUCCESS(nt_status)) {
+    ret_error = pRtlNtStatusToDosError(nt_status);
+    goto cleanup;
+  }
+  nt_status = pNtQueryDirectoryFile(handle,
+                                    NULL,
+                                    NULL,
+                                    NULL,
+                                    &io_status,
+                                    &dir_info,
+                                    sizeof(dir_info),
+                                    FileIdFullDirectoryInformation,
+                                    TRUE,
+                                    &FileMask,
+                                    TRUE);
+
+  /* Buffer overflow (a warning status code) is expected here since there isn't
+   * enough space to store the FileName, and actually indicates success. */
+  if (!NT_SUCCESS(nt_status) && nt_status != STATUS_BUFFER_OVERFLOW) {
+    if (nt_status == STATUS_NO_MORE_FILES)
+      ret_error = ERROR_PATH_NOT_FOUND;
+    else
+      ret_error = pRtlNtStatusToDosError(nt_status);
+    goto cleanup;
+  }
+
+  /* Assign values to stat_info */
+  memset(&stat_info, 0, sizeof(FILE_STAT_BASIC_INFORMATION));
+  stat_info.FileAttributes = dir_info.FileAttributes;
+  stat_info.CreationTime.QuadPart = dir_info.CreationTime.QuadPart;
+  stat_info.LastAccessTime.QuadPart = dir_info.LastAccessTime.QuadPart;
+  stat_info.LastWriteTime.QuadPart = dir_info.LastWriteTime.QuadPart;
+  if (stat_info.FileAttributes & FILE_ATTRIBUTE_REPARSE_POINT) {
+    /* A file handle is needed to get st_size for the link (from
+     * FSCTL_GET_REPARSE_POINT), which is required by posix, but we are here
+     * because getting the file handle failed. We could get just the
+     * ReparsePointTag by querying FILE_ID_EXTD_DIR_INFORMATION instead to make
+     * sure this really is a link before giving up here on the uv_fs_stat call,
+     * but that doesn't seem essential. */
+    if (!do_lstat)
+      goto cleanup;
+    stat_info.EndOfFile.QuadPart = 0;
+    stat_info.AllocationSize.QuadPart = 0;
+  } else {
+    stat_info.EndOfFile.QuadPart = dir_info.EndOfFile.QuadPart;
+    stat_info.AllocationSize.QuadPart = dir_info.AllocationSize.QuadPart;
+  }
+  stat_info.ChangeTime.QuadPart = dir_info.ChangeTime.QuadPart;
+  stat_info.FileId.QuadPart = dir_info.FileId.QuadPart;
+
+  /* Finish up by getting device info from the directory handle,
+   * since files presumably must live on their device. */
+  nt_status = pNtQueryVolumeInformationFile(handle,
+                                            &io_status,
+                                            &volume_info,
+                                            sizeof volume_info,
+                                            FileFsVolumeInformation);
+
+  /* Buffer overflow (a warning status code) is expected here. */
+  if (io_status.Status == STATUS_NOT_IMPLEMENTED) {
+    stat_info.VolumeSerialNumber.QuadPart = 0;
+  } else if (NT_ERROR(nt_status)) {
+    ret_error = pRtlNtStatusToDosError(nt_status);
+    goto cleanup;
+  } else {
+    stat_info.VolumeSerialNumber.QuadPart = volume_info.VolumeSerialNumber;
+  }
+
+  nt_status = pNtQueryVolumeInformationFile(handle,
+                                            &io_status,
+                                            &device_info,
+                                            sizeof device_info,
+                                            FileFsDeviceInformation);
+
+  /* Buffer overflow (a warning status code) is expected here. */
+  if (NT_ERROR(nt_status)) {
+    ret_error = pRtlNtStatusToDosError(nt_status);
+    goto cleanup;
+  }
+
+  stat_info.DeviceType = device_info.DeviceType;
+  stat_info.NumberOfLinks = 1; /* No way to recover this info. */
+
+  fs__stat_assign_statbuf(statbuf, stat_info, do_lstat);
+  ret_error = 0;
+
+cleanup:
+  if (split != 0)
+    path[split - 1] = splitchar;
+  if (handle != INVALID_HANDLE_VALUE)
+    CloseHandle(handle);
+  return ret_error;
+}
 
 INLINE static DWORD fs__stat_impl_from_path(WCHAR* path,
                                             int do_lstat,
@@ -1949,7 +2134,7 @@ INLINE static DWORD fs__stat_impl_from_path(WCHAR* path,
   DWORD flags;
   DWORD ret;
 
-  // If new API exists, try to use it.
+  /* If new API exists, try to use it. */
   switch (fs__stat_path(path, statbuf, do_lstat)) {
     case FS__STAT_PATH_SUCCESS:
       return 0;
@@ -1959,7 +2144,7 @@ INLINE static DWORD fs__stat_impl_from_path(WCHAR* path,
       break;
   }
 
-  // If the new API does not exist, use the old API.
+  /* If the new API does not exist, use the old API. */
   flags = FILE_FLAG_BACKUP_SEMANTICS;
   if (do_lstat)
     flags |= FILE_FLAG_OPEN_REPARSE_POINT;
@@ -1972,8 +2157,12 @@ INLINE static DWORD fs__stat_impl_from_path(WCHAR* path,
                        flags,
                        NULL);
 
-  if (handle == INVALID_HANDLE_VALUE)
+  if (handle == INVALID_HANDLE_VALUE) {
-    return GetLastError();
+    ret = GetLastError();
+    if (ret != ERROR_ACCESS_DENIED && ret != ERROR_SHARING_VIOLATION)
+      return ret;
+    return fs__stat_directory(path, statbuf, do_lstat, ret);
+  }
 
   if (fs__stat_handle(handle, statbuf, do_lstat) != 0)
     ret = GetLastError();

src/win/winapi.h

@@ -4287,6 +4287,22 @@ typedef struct _FILE_BOTH_DIR_INFORMATION {
   WCHAR FileName[1];
 } FILE_BOTH_DIR_INFORMATION, *PFILE_BOTH_DIR_INFORMATION;
 
+typedef struct _FILE_ID_FULL_DIR_INFORMATION {
+  ULONG         NextEntryOffset;
+  ULONG         FileIndex;
+  LARGE_INTEGER CreationTime;
+  LARGE_INTEGER LastAccessTime;
+  LARGE_INTEGER LastWriteTime;
+  LARGE_INTEGER ChangeTime;
+  LARGE_INTEGER EndOfFile;
+  LARGE_INTEGER AllocationSize;
+  ULONG         FileAttributes;
+  ULONG         FileNameLength;
+  ULONG         EaSize;
+  LARGE_INTEGER FileId;
+  WCHAR         FileName[1];
+} FILE_ID_FULL_DIR_INFORMATION, *PFILE_ID_FULL_DIR_INFORMATION;
+
 typedef struct _FILE_BASIC_INFORMATION {
   LARGE_INTEGER CreationTime;
   LARGE_INTEGER LastAccessTime;

test/test-fs.c

@@ -4507,6 +4507,60 @@ TEST_IMPL(fs_open_readonly_acl) {
     MAKE_VALGRIND_HAPPY(loop);
     return 0;
 }
+
+TEST_IMPL(fs_stat_no_permission) {
+    uv_passwd_t pwd;
+    uv_fs_t req;
+    int r;
+    char* filename = "test_file_no_permission.txt";
+
+    /* Setup - clear the ACL and remove the file */
+    loop = uv_default_loop();
+    r = uv_os_get_passwd(&pwd);
+    ASSERT_OK(r);
+    call_icacls("icacls %s /remove *S-1-1-0:(F)", filename);
+    unlink(filename);
+
+    /* Create the file */
+    r = uv_fs_open(loop,
+                   &open_req1,
+                   filename,
+                   UV_FS_O_RDONLY | UV_FS_O_CREAT,
+                   S_IRUSR,
+                   NULL);
+    ASSERT_GE(r, 0);
+    ASSERT_GE(open_req1.result, 0);
+    uv_fs_req_cleanup(&open_req1);
+    r = uv_fs_close(NULL, &close_req, open_req1.result, NULL);
+    ASSERT_OK(r);
+    ASSERT_OK(close_req.result);
+    uv_fs_req_cleanup(&close_req);
+
+    /* Set up ACL */
+    r = call_icacls("icacls %s /deny *S-1-1-0:(F)", filename);
+    if (r != 0) {
+        goto acl_cleanup;
+    }
+
+    /* Read file stats */
+    r = uv_fs_stat(NULL, &req, filename, NULL);
+    if (r != 0) {
+        goto acl_cleanup;
+    }
+
+    uv_fs_req_cleanup(&req);
+
+ acl_cleanup:
+    /* Cleanup */
+    call_icacls("icacls %s /reset", filename);
+    uv_fs_unlink(NULL, &unlink_req, filename, NULL);
+    uv_fs_req_cleanup(&unlink_req);
+    unlink(filename);
+    uv_os_free_passwd(&pwd);
+    ASSERT_OK(r);
+    MAKE_VALGRIND_HAPPY(loop);
+    return 0;
+}
 #endif
 
 #ifdef _WIN32

test/test-list.h

@@ -514,6 +514,7 @@ TEST_DECLARE   (environment_creation)
 TEST_DECLARE   (listen_with_simultaneous_accepts)
 TEST_DECLARE   (listen_no_simultaneous_accepts)
 TEST_DECLARE   (fs_stat_root)
+TEST_DECLARE   (fs_stat_no_permission)
 TEST_DECLARE   (spawn_with_an_odd_path)
 TEST_DECLARE   (spawn_no_path)
 TEST_DECLARE   (spawn_no_ext)
@@ -1043,6 +1044,7 @@ TASK_LIST_START
   TEST_ENTRY  (listen_with_simultaneous_accepts)
   TEST_ENTRY  (listen_no_simultaneous_accepts)
   TEST_ENTRY  (fs_stat_root)
+  TEST_ENTRY  (fs_stat_no_permission)
   TEST_ENTRY  (spawn_with_an_odd_path)
   TEST_ENTRY  (spawn_no_path)
   TEST_ENTRY  (spawn_no_ext)