Reject zip archives whose entry names are not valid UTF-8.

bug: 18584205
Change-Id: Iaf3e8211dab6a1e3923f7fee6ea7fc693972dba3

1 files changed, 59 insertions, 0 deletions

diff --git a/libziparchive/entry_name_utils-inl.h b/libziparchive/entry_name_utils-inl.h
new file mode 100644
index 0000000..ddbc286
--- /dev/null
+++ b/libziparchive/entry_name_utils-inl.h
@@ -0,0 +1,59 @@
+/*
+ * 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>
+
+// Check if |length| bytes at |entry_name| constitute a valid entry name.
+// Entry names must be valid UTF-8 and must not contain '0'.
+inline bool IsValidEntryName(const uint8_t* entry_name, const size_t length) {
+  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 = byte << 1; first & 0x80; first <<= 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_