From e0175ca7e440a87e9d03f249fc8f210063df7908 Mon Sep 17 00:00:00 2001
From: Elliott Hughes <enh@google.com>
Date: Thu, 14 Mar 2013 14:38:08 -0700
Subject: [PATCH] Don't search off the end of the index for bad Olson ids.

In the old code, the index was a file to itself, so it made sense to
read until you hit the end of the file. In the new code, the index is
followed by hundreds of KiB of data, so we need to just search the
index.

Bug: 8368791
Change-Id: Icf5f8b5516cf3a93679fa849c9f6cd1cb100e0f1
---
 libc/tzcode/localtime.c |  8 +++++++-
 tests/Android.mk        |  1 +
 tests/time_test.cpp     | 44 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 52 insertions(+), 1 deletion(-)
 create mode 100644 tests/time_test.cpp

diff --git a/libc/tzcode/localtime.c b/libc/tzcode/localtime.c
index 689bbd318..8a54e81cc 100644
--- a/libc/tzcode/localtime.c
+++ b/libc/tzcode/localtime.c
@@ -2305,7 +2305,13 @@ static int __bionic_open_tzdata_path(const char* path, const char* olson_id, int
 
   static const size_t NAME_LENGTH = 40;
   unsigned char buf[NAME_LENGTH + 3 * sizeof(int32_t)];
-  while (TEMP_FAILURE_RETRY(read(fd, buf, sizeof(buf))) == (ssize_t) sizeof(buf)) {
+
+  size_t id_count = (ntohl(header.data_offset) - ntohl(header.index_offset)) / sizeof(buf);
+  for (size_t i = 0; i < id_count; ++i) {
+    if (TEMP_FAILURE_RETRY(read(fd, buf, sizeof(buf))) != (ssize_t) sizeof(buf)) {
+      break;
+    }
+
     char this_id[NAME_LENGTH + 1];
     memcpy(this_id, buf, NAME_LENGTH);
     this_id[NAME_LENGTH] = '\0';
diff --git a/tests/Android.mk b/tests/Android.mk
index 633a6a991..46427ecea 100644
--- a/tests/Android.mk
+++ b/tests/Android.mk
@@ -74,6 +74,7 @@ test_src_files = \
     string_test.cpp \
     strings_test.cpp \
     stubs_test.cpp \
+    time_test.cpp \
     unistd_test.cpp \
 
 test_dynamic_ldflags = -Wl,--export-dynamic -Wl,-u,DlSymTestFunction
diff --git a/tests/time_test.cpp b/tests/time_test.cpp
new file mode 100644
index 000000000..9a5a70670
--- /dev/null
+++ b/tests/time_test.cpp
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2013 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.
+ */
+
+#include <sys/cdefs.h>
+#include <features.h>
+#include <gtest/gtest.h>
+
+#include <time.h>
+
+#ifdef __BIONIC__ // mktime_tz is a bionic extension.
+#include <libc/private/bionic_time.h>
+TEST(time, mktime_tz) {
+  struct tm epoch;
+  memset(&epoch, 0, sizeof(tm));
+  epoch.tm_year = 1970 - 1900;
+  epoch.tm_mon = 1;
+  epoch.tm_mday = 1;
+
+  // Alphabetically first. Coincidentally equivalent to UTC.
+  ASSERT_EQ(2678400, mktime_tz(&epoch, "Africa/Abidjan"));
+
+  // Alphabetically last. Coincidentally equivalent to UTC.
+  ASSERT_EQ(2678400, mktime_tz(&epoch, "Zulu"));
+
+  // Somewhere in the middle, not UTC.
+  ASSERT_EQ(2707200, mktime_tz(&epoch, "America/Los_Angeles"));
+
+  // Missing. Falls back to UTC.
+  ASSERT_EQ(2678400, mktime_tz(&epoch, "PST"));
+}
+#endif