#201 Memory leak in contrib/gregbook/readpng.c

[Alexey Alexeev]

Memory leak in contrib/gregbook/readpng.c

In function readpng_get_image: if error happens at png_read_image(…) we go to setjmp(…) where png_ptr and info_ptr will be deleted, but image_data and row_pointers does not.

Possible fix: change what setjmp(…) to this:

if (setjmp(png_jmpbuf(png_ptr))) {
    png_destroy_read_struct(&png_ptr, &info_ptr, NULL);
    free(image_data);
    free(row_pointers);
    return NULL;
}

[Glenn Randers-Pehrson]

Thanks. It's probably safer this way:

diff a/contrib/gregbook/readpng.c b/contrib/gregbook/readpng.c
217a218,225

    if (image_data != NULL) {
       free(image_data);
       image_data = NULL;
    }
    if (row_pointers != NULL) {
       free(row_pointers);
       row_pointers = NULL;
    }

[Glenn Randers-Pehrson]

It's been pointed out to me that it's not necessary to check for the NULL pointers; readpng.c guarantees that they are initialized to NULL.
The patch has been applied to the libpngNN branches of the libpng GIT repository and will appear in the next releases.

[Glenn Randers-Pehrson]

Fixed in libpng-1.5.15 and libpng-1.6.1, thanks.