Re: [Dvipng] dvipng crash in stringrgb function

[Ahzo]

Hi,

Thanks for your quick reply!

Unfortunately, when I tried to built from current git HEAD, autoreconf failed:
$ autoreconf
/usr/bin/m4:acinclude.m4:295: ERROR: end of file in string
autom4te: /usr/bin/m4 failed with exit status: 1
aclocal: error: echo failed with exit status: 1
autoreconf: aclocal failed with exit status: 1

It seems commit 980ba1d broke acinclude.m4. Restoring it to the previous state 
lets autoreconf succeed again.
Thus I can confirm that the stringrgb crash is now fixed.

However, I found another crash:
$ dvipng -pp- -
This is dvipng 1.15 Copyright 2002-2015 Jan-Ake Larsson

Usage: dvipng [OPTION]... FILENAME[.dvi]
[...]
   # = number   f = file   s = string  * = suffix, '0' to turn off
       c = comma-separated dimension pair (e.g., 3.2in,-32.1cm)

Segmentation fault


This can be avoided by validating the dvi pointer, before trying to access it:
--- a/draw.c
+++ b/draw.c
@@ -313,11 +313,12 @@ static void DrawPage(dviunits hoffset, dviunits voffset)

void DrawPages(void)
{
-  struct page_list *dvi_pos;
+  struct page_list *dvi_pos = NULL;
   pixels x_width,y_width,x_offset,y_offset;
   int pagecounter=(option_flags & DVI_PAGENUM)?0:10;

-  dvi_pos=NextPPage(dvi,NULL);
+  if (dvi!=NULL)
+    dvi_pos=NextPPage(dvi,NULL);
   if (dvi_pos!=NULL) {
     while(dvi_pos!=NULL) {
       SeekPage(dvi,dvi_pos);

Best,
Ahzo