From 0512c63533d20634bad25f133f3094abbae7cda3 Mon Sep 17 00:00:00 2001
From: Glenn Randers-Pehrson <glennrp at users.sourceforge.net>
Date: Wed, 27 Sep 2017 18:05:07 -0500
Subject: [PATCH] [libpng16] Revert contrib/oss-fuzz/libpng_read_fuzzer.cc to
 libpng-1.6.32 status

---
 contrib/oss-fuzz/libpng_read_fuzzer.cc | 66 ++++++--------------------
 1 file changed, 15 insertions(+), 51 deletions(-)

diff --git a/contrib/oss-fuzz/libpng_read_fuzzer.cc b/contrib/oss-fuzz/libpng_read_fuzzer.cc
index 0fc9e206c..c1b16249d 100644
--- a/contrib/oss-fuzz/libpng_read_fuzzer.cc
+++ b/contrib/oss-fuzz/libpng_read_fuzzer.cc
@@ -5,14 +5,13 @@
 // Use of this source code is governed by a BSD-style license that may
 // be found in the LICENSE file https://cs.chromium.org/chromium/src/LICENSE
 
-// Last changed in libpng 1.6.33beta03 [September 27, 2017]
+// Last changed in libpng 1.6.32 [August 24, 2017]
 
 // The modifications in 2017 by Glenn Randers-Pehrson include
 // 1. addition of a PNG_CLEANUP macro,
 // 2. setting the option to ignore ADLER32 checksums,
 // 3. adding "#include <string.h>" which is needed on some platforms
 //    to provide memcpy().
-// 4. adding read_end_info() and creating an end_info structure.
 
 #include <stddef.h>
 #include <stdint.h>
@@ -23,6 +22,16 @@
 #define PNG_INTERNAL
 #include "png.h"
 
+#define PNG_CLEANUP \
+    if(png_handler.png_ptr) \
+    { \
+      if (png_handler.info_ptr) \
+        png_destroy_read_struct(&png_handler.png_ptr, &png_handler.info_ptr,\
+          nullptr); \
+      else \
+        png_destroy_read_struct(&png_handler.png_ptr, nullptr, nullptr); \
+     }
+
 struct BufState {
   const uint8_t* data;
   size_t bytes_left;
@@ -31,19 +40,16 @@ struct BufState {
 struct PngObjectHandler {
   png_infop info_ptr = nullptr;
   png_structp png_ptr = nullptr;
-  png_infop end_info_ptr = nullptr;
   png_voidp row_ptr = nullptr;
   BufState* buf_state = nullptr;
 
   ~PngObjectHandler() {
-    if (row_ptr)
+    if (row_ptr && png_ptr) {
       png_free(png_ptr, row_ptr);
-    if (end_info_ptr)
-      png_destroy_read_struct(&png_ptr, &info_ptr, &end_info_ptr);
-    else if (info_ptr) 
+    }
+    if (png_ptr && info_ptr) {
       png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
-    else
-      png_destroy_read_struct(&png_ptr, nullptr, nullptr);
+    }
     delete buf_state;
   }
 };
@@ -63,7 +69,6 @@ static const int kPngHeaderSize = 8;
 // Entry point for LibFuzzer.
 // Roughly follows the libpng book example:
 // http://www.libpng.org/pub/png/book/chapter13.html
-
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   if (size < kPngHeaderSize) {
     return 0;
@@ -76,53 +81,19 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   }
 
   PngObjectHandler png_handler;
-  png_handler.png_ptr = nullptr;
-  png_handler.row_ptr = nullptr;
-  png_handler.info_ptr = nullptr;
-  png_handler.end_info_ptr = nullptr;
-
   png_handler.png_ptr = png_create_read_struct
     (PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
   if (!png_handler.png_ptr) {
     return 0;
   }
 
-#define PNG_CLEANUP \
-  if(png_handler.png_ptr) \
-  { \
-    if (png_handler.row_ptr) \
-      png_free(png_handler.png_ptr, png_handler.row_ptr); \
-    if (png_handler.end_info_ptr) \
-      png_destroy_read_struct(&png_handler.png_ptr, &png_handler.info_ptr,\
-        &png_handler.end_info_ptr); \
-    else if (png_handler.info_ptr) \
-      png_destroy_read_struct(&png_handler.png_ptr, &png_handler.info_ptr,\
-        nullptr); \
-    else \
-      png_destroy_read_struct(&png_handler.png_ptr, nullptr, nullptr); \
-    png_handler.png_ptr = nullptr; \
-    png_handler.row_ptr = nullptr; \
-    png_handler.info_ptr = nullptr; \
-    png_handler.end_info_ptr = nullptr; \
-  }
-
   png_handler.info_ptr = png_create_info_struct(png_handler.png_ptr);
   if (!png_handler.info_ptr) {
     PNG_CLEANUP
     return 0;
   }
 
-  png_handler.end_info_ptr = png_create_info_struct(png_handler.png_ptr);
-  if (!png_handler.end_info_ptr) {
-    PNG_CLEANUP
-    return 0;
-  }
-
-  /* Treat benign errors as warnings */
-  png_set_benign_errors(png_handler.png_ptr, 1);
-
   png_set_crc_action(png_handler.png_ptr, PNG_CRC_QUIET_USE, PNG_CRC_QUIET_USE);
-
 #ifdef PNG_IGNORE_ADLER32
   png_set_option(png_handler.png_ptr, PNG_IGNORE_ADLER32, PNG_OPTION_ON);
 #endif
@@ -141,7 +112,6 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
 
   // Reading.
   png_read_info(png_handler.png_ptr, png_handler.info_ptr);
-  png_read_update_info(png_handler.png_ptr, png_handler.info_ptr);
   png_handler.row_ptr = png_malloc(
       png_handler.png_ptr, png_get_rowbytes(png_handler.png_ptr,
                                                png_handler.info_ptr));
@@ -172,7 +142,6 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   int passes = png_set_interlace_handling(png_handler.png_ptr);
   png_start_read_image(png_handler.png_ptr);
 
-  /* To do: prevent the optimizer from removing this code entirely */
   for (int pass = 0; pass < passes; ++pass) {
     for (png_uint_32 y = 0; y < height; ++y) {
       png_read_row(png_handler.png_ptr,
@@ -180,11 +149,6 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
     }
   }
 
-  png_read_end(png_handler.png_ptr, png_handler.end_info_ptr);
-
   PNG_CLEANUP
-
-  /* TO do: exercise the progressive reader here */
-
   return 0;
 }