2009.04.30 19:31 "Re: [Tiff] Packbits worst case encoded length", by Albert Cahalan

On Thu, Apr 30, 2009 at 3:25 PM, Toby Thain <toby@telegraphics.com.au> wrote:

On 30-Apr-09, at 3:12 PM, Albert Cahalan wrote:

On Thu, Apr 30, 2009 at 9:58 AM, Toby Thain <toby@telegraphics.com.au> wrote:

At the very least, you can have an #ifdef to enable memory protection on platforms that can support it. Windows and all the typical UNIX-like systems offer this.

They offer it for processes for 'free', as far as an application developer is concerned.

Whether libtiff should use such a facility directly? Well, the debate is open, I guess.

The alternative is that every app is structured like Google Chrome. It's a really sad result.

BTW, since infinite portability is far too costly for the value it provides, you do draw a line somewhere. Crummy platforms are likely to be writing files only, not reading them. (embedded OSes in cameras, scanners, etc.) At most they need to read their own files, which will of course be well-formed.

Going without the memory protection is really really bad.

I don't, and haven't since Mac OS 9. And my Linux and Solaris systems don't do without it either.

Ah, but you do. Regular malloc doesn't put guard pages around memory allocations. The memory protection is there in your OS, but it's not getting full use.