1 files changed, 65 insertions, 0 deletions
diff --git a/libziparchive/entry_name_utils-inl.h b/libziparchive/entry_name_utils-inl.h
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+++ b/libziparchive/entry_name_utils-inl.h
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * 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.
+ */
+
+#ifndef LIBZIPARCHIVE_ENTRY_NAME_UTILS_INL_H_
+#define LIBZIPARCHIVE_ENTRY_NAME_UTILS_INL_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <limits>
+
+// Check if |length| bytes at |entry_name| constitute a valid entry name.
+// Entry names must be valid UTF-8 and must not contain '0'. They also must
+// fit into the central directory record.
+inline bool IsValidEntryName(const uint8_t* entry_name, const size_t length) {
+  if (length > std::numeric_limits<uint16_t>::max()) {
+    return false;
+  }
+  for (size_t i = 0; i < length; ++i) {
+    const uint8_t byte = entry_name[i];
+    if (byte == 0) {
+      return false;
+    } else if ((byte & 0x80) == 0) {
+      // Single byte sequence.
+      continue;
+    } else if ((byte & 0xc0) == 0x80 || (byte & 0xfe) == 0xfe) {
+      // Invalid sequence.
+      return false;
+    } else {
+      // 2-5 byte sequences.
+      for (uint8_t first = static_cast<uint8_t>((byte & 0x7f) << 1); first & 0x80;
+           first = static_cast<uint8_t>((first & 0x7f) << 1)) {
+        ++i;
+
+        // Missing continuation byte..
+        if (i == length) {
+          return false;
+        }
+
+        // Invalid continuation byte.
+        const uint8_t continuation_byte = entry_name[i];
+        if ((continuation_byte & 0xc0) != 0x80) {
+          return false;
+        }
+      }
+    }
+  }
+
+  return true;
+}
+
+#endif  // LIBZIPARCHIVE_ENTRY_NAME_UTILS_INL_H_