Re: [PATCH 0/1] MR7099: windowscodecs: Simplify png_decoder_get_metadata_blocks using realloc.

[Alfred Agrell (＠Alcaro)]

Alfred Agrell (@Alcaro) commented about dlls/windowscodecs/libpng.c:
>          /* This chunk is considered metadata. */
>          if (*count == metadata_blocks_size)
>          {
> -
>            struct decoder_block *new_metadata_blocks;
> -
>            ULONG new_metadata_blocks_size;
> -
> -
>            new_metadata_blocks_size = 4 + metadata_blocks_size * 2;
> -
>            new_metadata_blocks = malloc(new_metadata_blocks_size * sizeof(*new_metadata_blocks));
> -
>            metadata_blocks_size = 4 + metadata_blocks_size * 2;
> -
>            result = realloc(result, metadata_blocks_size * sizeof(*result));

If realloc fails, the original memory area remains unchanged. x = realloc(x, y) loses the original pointer, yielding a memory leak.