ref: 7227aabb3e45e46cf320f56503656c39f8b63b30
parent: dbf9142f7e0432c9ed618b3276e2b61fa39e7262
author: Werner Lemberg <wl@gnu.org>
date: Thu Mar 4 01:41:30 EST 2021
Revert "[sfnt] Fix crash in `Load_SBit_Png` on Windows x64." This reverts commit dbf9142f7e0432c9ed618b3276e2b61fa39e7262, as discussed in #1037.
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,28 +1,3 @@
-2021-02-27 Jesse Towner <townerj@gmail.com>
-
- [sfnt] Fix crash in `Load_SBit_Png` on Windows x64.
-
- This change fixes a crash that occurs in `Load_SBit_Png` when
- running on a 64-bit Windows OS. A memory access violation exception
- would be raised by `setjmp` if the `jmp_buf` is not aligned to a
- 16-byte memory boundary. This is due to setjmp executing `movdqa`
- instructions to store 128-bit XMM registers to memory, which require
- correct memory alignment. This problem occurs because
- `png_create_read_struct` uses `malloc` and `free` for memory
- management, which only guarantees 8-byte alignment on Windows.
-
- Instead, to fix the problem, `png_create_read_struct_2` is used on
- 64-bit Windows, which allows for user-defined memory allocation and
- deallocation callbacks to be specified. These callbacks forward the
- allocation and deallocation requests to `_aligned_alloc` and
- `_aligned_free`, ensuring that the allocated `png_struct` and
- internal `jmp_buf` have the requisite 16-byte alignment.
-
- * src/sfnt/pngshim.c <_WIN64>: Include `malloc.h`.
- (malloc_callback, free_callback) <_WIN64>: New functions.
- (Load_SBit_Png) <_WIN64>: Use `png_create_read_struct_2` instead of
- `png_create_read_struct`
-
2021-02-25 Werner Lemberg <wl@gnu.org>
[woff2] Fix memory leak.
--- a/src/sfnt/pngshim.c
+++ b/src/sfnt/pngshim.c
@@ -33,16 +33,6 @@
#include "sferrors.h"
- /* Use _aligned_malloc / _aligned_free on 64-bit Windows to ensure that */
- /* the jmp_buf needed for ft_setjmp is aligned to a 16-byte boundary. */
- /* If the jmp_buf is not aligned to a 16-byte boundary then a memory */
- /* access violation exception will occur upon ft_setjmp being called. */
-#ifdef _WIN64
-#ifndef PNG_USER_MEM_SUPPORTED
-#error "libpng user-defined memory allocation is required for 64-bit Windows"
-#endif
-#include <malloc.h>
-#endif
/* This code is freely based on cairo-png.c. There's so many ways */
/* to call libpng, and the way cairo does it is defacto standard. */
@@ -231,33 +221,7 @@
}
-#ifdef _WIN64
-
- /* Memory allocation callback to ensure that the jmp_buf that is stored */
- /* within the png_struct has 16-byte alignment for 64-bit Windows. */
- static png_voidp
- malloc_callback( png_structp png,
- png_alloc_size_t size )
- {- FT_UNUSED( png );
- return _aligned_malloc( size, 16 );
- }
-
-
- /* Memory deallocation callback to release memory that was allocated */
- /* with the matching memory allocation callback above. */
static void
- free_callback( png_structp png,
- png_voidp ptr )
- {- FT_UNUSED( png );
- _aligned_free( ptr );
- }
-
-#endif /* _WIN64 */
-
-
- static void
read_data_from_FT_Stream( png_structp png,
png_bytep data,
png_size_t length )
@@ -328,20 +292,10 @@
FT_Stream_OpenMemory( &stream, data, png_len );
-#ifdef _WIN64
- png = png_create_read_struct_2( PNG_LIBPNG_VER_STRING,
- &error,
- error_callback,
- warning_callback,
- NULL,
- malloc_callback,
- free_callback );
-#else
png = png_create_read_struct( PNG_LIBPNG_VER_STRING,
&error,
error_callback,
warning_callback );
-#endif
if ( !png )
{error = FT_THROW( Out_Of_Memory );