[libpng16] Renamed contrib/tools/fixitxt to contrib/tools/png-fix-itxt.

Added information in the documentation about problems with and fixes for
the bad CRC and bad iTXt chunk situations.

ANNOUNCE

@@ -1,5 +1,5 @@
 
-Libpng 1.6.3beta05 - May 8, 2013
+Libpng 1.6.3beta05 - May 9, 2013
 
 This is not intended to be a public release.  It will be replaced
 within a few weeks by a public version or by another test version.
@@ -45,7 +45,7 @@ Version 1.6.3beta04 [May 6, 2013]
   Calculate our own zlib windowBits when decoding rather than trusting the
     CMF bytes in the PNG datastream.
 
-Version 1.6.3beta05 [May 8, 2013]
+Version 1.6.3beta05 [May 9, 2013]
   Choose to use windowBits==15 or the zlib header setting via the
     benign-errors setting.  If benign errors are allowed, then ignore
     the windowBits setting in the zlib header.
@@ -72,6 +72,9 @@ Version 1.6.3beta05 [May 8, 2013]
   Attempt to detect configuration issues with pngdeflate, which requires
     both the correct libpng and the correct zlib to function correctly.
   Check ZLIB_VERNUM for mismatches, enclose #error in quotes
+  Renamed contrib/tools/fixitxt to contrib/tools/png-fix-itxt.
+  Added information in the documentation about problems with and fixes for
+  the bad CRC and bad iTXt chunk situations.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit

CHANGES

@@ -4528,7 +4528,7 @@ Version 1.6.3beta04 [May 6, 2013]
   Calculate our own zlib windowBits when decoding rather than trusting the
     CMF bytes in the PNG datastream.
 
-Version 1.6.3beta05 [May 8, 2013]
+Version 1.6.3beta05 [May 9, 2013]
   Choose to use windowBits==15 or the zlib header setting via the
     benign-errors setting.  If benign errors are allowed, then ignore
     the windowBits setting in the zlib header.
@@ -4555,6 +4555,9 @@ Version 1.6.3beta05 [May 8, 2013]
   Attempt to detect configuration issues with pngdeflate, which requires
     both the correct libpng and the correct zlib to function correctly.
   Check ZLIB_VERNUM for mismatches, enclose #error in quotes
+  Renamed contrib/tools/fixitxt to contrib/tools/png-fix-itxt.
+  Added information in the documentation about problems with and fixes for
+  the bad CRC and bad iTXt chunk situations.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit

Makefile.am

@@ -10,7 +10,7 @@ ACLOCAL_AMFLAGS = -I scripts
 check_PROGRAMS= pngtest pngunknown pngstest pngvalid
 
 # Utilities - installed
-bin_PROGRAMS= pngdeflate fixitxt
+bin_PROGRAMS= pngdeflate png-fix-itxt
 
 pngtest_SOURCES = pngtest.c
 pngtest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
@@ -27,7 +27,7 @@ pngunknown_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
 pngdeflate_SOURCES = contrib/tools/pngdeflate.c
 pngdeflate_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
 
-fixitxt_SOURCES = contrib/tools/fixitxt.c
+png_fix_itxt_SOURCES = contrib/tools/png-fix-itxt.c
 
 # Generally these are single line shell scripts to run a test with a particular
 # set of parameters:
@@ -196,7 +196,7 @@ $(srcdir)/scripts/pnglibconf.h.prebuilt:
 # an installed one (this can happen immediately after on a clean system if
 # 'make test' is the first thing the user does.)
 pngstest.o pngvalid.o pngtest.o pngunknown.o timepng.o: pnglibconf.h
-pngdeflate.o fixitxt.o: pnglibconf.h
+pngdeflate.o png-fix-itxt.o: pnglibconf.h
 
 # We must use -DPNG_NO_USE_READ_MACROS here even when the library may actually
 # be built with PNG_USE_READ_MACROS; this prevents the read macros from

contrib/tools/png-fix-itxt.c

@@ -1,8 +1,8 @@
-#include <stdio.h>
 
-/* fixitxt version 1.0.0
+/* png-fix-itxt version 1.0.0
  *
  * Copyright 2013 Glenn Randers-Pehrson
+ * Last changed in libpng 1.6.3 [(PENDING RELEASE)]
  *
  * This code is released under the libpng license.
  * For conditions of distribution and use, see the disclaimer
@@ -10,7 +10,7 @@
  *
  * Usage:            
  *
- *     fixitxt.exe < bad.png > good.png
+ *     png-fix-itxt.exe < bad.png > good.png
  *
  * Fixes a PNG file written with libpng-1.6.0 or 1.6.1 that has one or more
  * uncompressed iTXt chunks.  Assumes that the actual length is greater
@@ -22,8 +22,14 @@
  *
  * Requires zlib (for crc32 and Z_NULL); build with
  *
- *     gcc -O -o fixitxt fixitxt.c -lz
+ *     gcc -O -o png-fix-itxt png-fix-itxt.c -lz
+ *
+ * If you need to handle iTXt chunks larger than 500000 kbytes you must
+ * rebuild png-fix-itxt with a larger values of MAX_LENGTH (or a smaller value
+ * if you know you will never encounter such huge iTXt chunks).
  */
+
+#include <stdio.h>
 #include <zlib.h>
 
 #define MAX_LENGTH 500000

contrib/tools/pngdeflate.c

@@ -691,8 +691,8 @@ fix_one(FILE *fp, FILE *fpIn, IDAT_info *info, png_uint_32 max_IDAT, int strip)
             }
          } /* while len > 0 && state < 4 */
 
-         /* The above loop only exits on 0 bytes left or end of stream, if
+         /* The above loop only exits on 0 bytes left or end of stream. If
-          * the stream ended with bytes left discard them:
+          * the stream ended with bytes left, discard them:
           */
          if (len > 0)
          {
@@ -723,7 +723,7 @@ fix_one(FILE *fp, FILE *fpIn, IDAT_info *info, png_uint_32 max_IDAT, int strip)
                case 1:  /* Keep gAMA, sRGB */
                   if (tag == png_gAMA || tag == png_sRGB)
                      break;
-                  /* Fall trhough */
+                  /* Fall through */
 
                default: /* Keep only IHDR, PLTE, tRNS */
                   if (tag == png_IHDR || tag == png_PLTE || tag == png_tRNS)

libpng-manual.txt

@@ -1,6 +1,6 @@
 libpng-manual.txt - A description on how to use and modify libpng
 
- libpng version 1.6.3beta05 - May 6, 2013
+ libpng version 1.6.3beta05 - May 9, 2013
  Updated and distributed by Glenn Randers-Pehrson
  <glennrp at users.sourceforge.net>
  Copyright (c) 1998-2013 Glenn Randers-Pehrson
@@ -11,7 +11,7 @@ libpng-manual.txt - A description on how to use and modify libpng
 
  Based on:
 
- libpng versions 0.97, January 1998, through 1.6.3beta05 - May 6, 2013
+ libpng versions 0.97, January 1998, through 1.6.3beta05 - May 9, 2013
  Updated and distributed by Glenn Randers-Pehrson
  Copyright (c) 1998-2013 Glenn Randers-Pehrson
 
@@ -5035,6 +5035,20 @@ The machine-generated configure files are no longer included in branches
 libpng16 and later of the GIT repository.  They continue to be included
 in the tarball releases, however.
 
+Libpng-1.6.0 and later use the CMF bytes at the beginning of the IDAT stream
+to set the size of the sliding window for reading instead of using the default
+32-kbyte sliding window size.  It was discovered that there are hundreds of PNG
+files in the wild that have incorrect CMF bytes that cause libpng to now issue
+a "too far back" error and reject the file.  Libpng-1.6.3 provides a way to
+revert to the libpng-1.5.x behavior (ignoring the CMF bytes and using a 32-kbyte
+sliding window), and provides a tool (called "contrib/tools/pnginflate"),
+for optimizing the CMF bytes correctly.
+
+Libpng-1.6.0 and libpng-1.6.1 wrote uncompressed iTXt chunks with the wrong
+length, which resulted in PNG files that cannot be read beyond the bad iTXt
+chunk.  This error was fixed in libpng-1.6.3, and a tool (called
+contrib/tools/png-fix-itxt) has been added to the libpng distribution.
+
 XIII.  Detecting libpng
 
 The png_get_io_ptr() function has been present since libpng-0.88, has never
@@ -5197,7 +5211,7 @@ Other rules can be inferred by inspecting the libpng source.
 
 XVI. Y2K Compliance in libpng
 
-May 6, 2013
+May 9, 2013
 
 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.

libpng.3

@@ -1,4 +1,4 @@
-.TH LIBPNG 3 "May 6, 2013"
+.TH LIBPNG 3 "May 9, 2013"
 .SH NAME
 libpng \- Portable Network Graphics (PNG) Reference Library 1.6.3beta05
 .SH SYNOPSIS
@@ -504,7 +504,7 @@ Following is a copy of the libpng-manual.txt file that accompanies libpng.
 .SH LIBPNG.TXT
 libpng-manual.txt - A description on how to use and modify libpng
 
- libpng version 1.6.3beta05 - May 6, 2013
+ libpng version 1.6.3beta05 - May 9, 2013
  Updated and distributed by Glenn Randers-Pehrson
  <glennrp at users.sourceforge.net>
  Copyright (c) 1998-2013 Glenn Randers-Pehrson
@@ -515,7 +515,7 @@ libpng-manual.txt - A description on how to use and modify libpng
 
  Based on:
 
- libpng versions 0.97, January 1998, through 1.6.3beta05 - May 6, 2013
+ libpng versions 0.97, January 1998, through 1.6.3beta05 - May 9, 2013
  Updated and distributed by Glenn Randers-Pehrson
  Copyright (c) 1998-2013 Glenn Randers-Pehrson
 
@@ -5540,6 +5540,20 @@ The machine-generated configure files are no longer included in branches
 libpng16 and later of the GIT repository.  They continue to be included
 in the tarball releases, however.
 
+Libpng-1.6.0 and later use the CMF bytes at the beginning of the IDAT stream
+to set the size of the sliding window for reading instead of using the default
+32-kbyte sliding window size.  It was discovered that there are hundreds of PNG
+files in the wild that have incorrect CMF bytes that cause libpng to now issue
+a "too far back" error and reject the file.  Libpng-1.6.3 provides a way to
+revert to the libpng-1.5.x behavior (ignoring the CMF bytes and using a 32-kbyte
+sliding window), and provides a tool (called "contrib/tools/pnginflate"),
+for optimizing the CMF bytes correctly.
+
+Libpng-1.6.0 and libpng-1.6.1 wrote uncompressed iTXt chunks with the wrong
+length, which resulted in PNG files that cannot be read beyond the bad iTXt
+chunk.  This error was fixed in libpng-1.6.3, and a tool (called
+contrib/tools/png-fix-itxt) has been added to the libpng distribution.
+
 .SH XIII.  Detecting libpng
 
 The png_get_io_ptr() function has been present since libpng-0.88, has never
@@ -5702,7 +5716,7 @@ Other rules can be inferred by inspecting the libpng source.
 
 .SH XVI. Y2K Compliance in libpng
 
-May 6, 2013
+May 9, 2013
 
 Since the PNG Development group is an ad-hoc body, we can't make
 an official declaration.
@@ -5979,7 +5993,7 @@ possible without all of you.
 
 Thanks to Frank J. T. Wojcik for helping with the documentation.
 
-Libpng version 1.6.3beta05 - May 6, 2013:
+Libpng version 1.6.3beta05 - May 9, 2013:
 Initially created in 1995 by Guy Eric Schalnat, then of Group 42, Inc.
 Currently maintained by Glenn Randers-Pehrson (glennrp at users.sourceforge.net).
 
@@ -6002,7 +6016,7 @@ this sentence.
 
 This code is released under the libpng license.
 
-libpng versions 1.2.6, August 15, 2004, through 1.6.3beta05, May 6, 2013, are
+libpng versions 1.2.6, August 15, 2004, through 1.6.3beta05, May 9, 2013, are
 Copyright (c) 2004,2006-2007 Glenn Randers-Pehrson, and are
 distributed according to the same disclaimer and license as libpng-1.2.5
 with the following individual added to the list of Contributing Authors
@@ -6101,7 +6115,7 @@ certification mark of the Open Source Initiative.
 
 Glenn Randers-Pehrson
 glennrp at users.sourceforge.net
-May 6, 2013
+May 9, 2013
 
 .\" end of man page