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pngdec: set memory functions

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use png_create_read_struct_2 to set a malloc function allowing the code
to fail on large allocations while fuzzing

Change-Id: Iaca1b93ecc6570067708f3ae2db07fbca74386ee
This commit is contained in:
James Zern 2018-09-28 07:32:56 +00:00
parent 50d8345ae6
commit bc5092b162
1 changed files with 17 additions and 1 deletions
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18
imageio/pngdec.c
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@ -18,6 +18,9 @@
#include <stdio.h>
#ifdef WEBP_HAVE_PNG
#ifndef PNG_USER_MEM_SUPPORTED
#define PNG_USER_MEM_SUPPORTED // for png_create_read_struct_2
#endif
#include <png.h>
#include <setjmp.h> // note: this must be included *after* png.h
#include <stdlib.h>
@ -32,6 +35,18 @@ static void PNGAPI error_function(png_structp png, png_const_charp error) {
longjmp(png_jmpbuf(png), 1);
}
static png_voidp MallocFunc(png_structp png_ptr, png_alloc_size_t size) {
(void)png_ptr;
if (size != (size_t)size) return NULL;
if (!ImgIoUtilCheckSizeArgumentsOverflow(size, 1)) return NULL;
return (png_voidp)malloc((size_t)size);
}
static void FreeFunc(png_structp png_ptr, png_voidp ptr) {
(void)png_ptr;
free(ptr);
}
// Converts the NULL terminated 'hexstring' which contains 2-byte character
// representations of hex values to raw data.
// 'hexstring' may contain values consisting of [A-F][a-f][0-9] in pairs,
@ -224,7 +239,8 @@ int ReadPNG(const uint8_t* const data, size_t data_size,
context.data = data;
context.data_size = data_size;
png = png_create_read_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0);
png = png_create_read_struct_2(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL,
NULL, MallocFunc, FreeFunc);
if (png == NULL) goto End;
png_set_error_fn(png, 0, error_function, NULL);