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From 56d6bc2e8855d25e03816509a0137c3a70410ae6 Mon Sep 17 00:00:00 2001
From: Glenn Randers-Pehrson <glennrp at users.sourceforge.net>
Date: Mon, 29 Apr 2013 08:57:14 -0500
Subject: [PATCH 06/10] [libpng16] Avoid dereferencing NULL pointer possibly
returned from
png_create_write_struct() (Andrew Church).
---
ANNOUNCE | 6 ++++--
CHANGES | 4 +++-
pngwrite.c | 65 +++++++++++++++++++++++++++++++-------------------------------
3 files changed, 39 insertions(+), 36 deletions(-)
(foutrelis: pruned non-code changes to apply cleanly to libpng 1.6.2.)
diff --git a/pngwrite.c b/pngwrite.c
index 33924aa..b71a3d3 100644
--- a/pngwrite.c
+++ b/pngwrite.c
@@ -494,51 +494,50 @@ png_create_write_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
png_structrp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
#endif /* PNG_USER_MEM_SUPPORTED */
+ if (png_ptr != NULL)
+ {
+ /* Set the zlib control values to defaults; they can be overridden by the
+ * application after the struct has been created.
+ */
+ png_ptr->zbuffer_size = PNG_ZBUF_SIZE;
- /* Set the zlib control values to defaults; they can be overridden by the
- * application after the struct has been created.
- */
- png_ptr->zbuffer_size = PNG_ZBUF_SIZE;
-
- /* The 'zlib_strategy' setting is irrelevant because png_default_claim in
- * pngwutil.c defaults it according to whether or not filters will be used,
- * and ignores this setting.
- */
- png_ptr->zlib_strategy = PNG_Z_DEFAULT_STRATEGY;
- png_ptr->zlib_level = PNG_Z_DEFAULT_COMPRESSION;
- png_ptr->zlib_mem_level = 8;
- png_ptr->zlib_window_bits = 15;
- png_ptr->zlib_method = 8;
+ /* The 'zlib_strategy' setting is irrelevant because png_default_claim in
+ * pngwutil.c defaults it according to whether or not filters will be
+ * used, and ignores this setting.
+ */
+ png_ptr->zlib_strategy = PNG_Z_DEFAULT_STRATEGY;
+ png_ptr->zlib_level = PNG_Z_DEFAULT_COMPRESSION;
+ png_ptr->zlib_mem_level = 8;
+ png_ptr->zlib_window_bits = 15;
+ png_ptr->zlib_method = 8;
#ifdef PNG_WRITE_COMPRESSED_TEXT_SUPPORTED
- png_ptr->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY;
- png_ptr->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION;
- png_ptr->zlib_text_mem_level = 8;
- png_ptr->zlib_text_window_bits = 15;
- png_ptr->zlib_text_method = 8;
+ png_ptr->zlib_text_strategy = PNG_TEXT_Z_DEFAULT_STRATEGY;
+ png_ptr->zlib_text_level = PNG_TEXT_Z_DEFAULT_COMPRESSION;
+ png_ptr->zlib_text_mem_level = 8;
+ png_ptr->zlib_text_window_bits = 15;
+ png_ptr->zlib_text_method = 8;
#endif /* PNG_WRITE_COMPRESSED_TEXT_SUPPORTED */
- /* This is a highly dubious configuration option; by default it is off, but
- * it may be appropriate for private builds that are testing extensions not
- * conformant to the current specification, or of applications that must not
- * fail to write at all costs!
- */
-# ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
+ /* This is a highly dubious configuration option; by default it is off,
+ * but it may be appropriate for private builds that are testing
+ * extensions not conformant to the current specification, or of
+ * applications that must not fail to write at all costs!
+ */
+#ifdef PNG_BENIGN_WRITE_ERRORS_SUPPORTED
png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
/* In stable builds only warn if an application error can be completely
* handled.
*/
-# endif
+#endif
- /* App warnings are warnings in release (or release candidate) builds but
- * are errors during development.
- */
-# if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
+ /* App warnings are warnings in release (or release candidate) builds but
+ * are errors during development.
+ */
+#if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
-# endif
+#endif
- if (png_ptr != NULL)
- {
/* TODO: delay this, it can be done in png_init_io() (if the app doesn't
* do it itself) avoiding setting the default function if it is not
* required.
--
1.8.2.2
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