Re: [PROPOSAL/PATCH] Remove PT_GNU_STACK support before 2.6.11

[Linus Torvalds]

On Sun, 6 Feb 2005, Arjan van de Ven wrote:
> 
> Note that these techniques all exist today. The only issue is that the
> current code doesn't do the RWE->READIMPLIESEXEC binding, which my patch
> fixed. 

My main objection to your patch is the naming. If 'executable_stack' 
affects the heap, then why is it called "executable_STACK"?

Wouldn't it be much nicer to

 - get rid of "EXSTACK_DEFAULT" as a special case, and instead just have 
   the architecture _initialize_ the damn variable to what it wants? In 
   other words, make it a nice understandable binary value (or maybe a 
   bitmask, if you want to have separate flags for stack/heap/mmap), 
   rather than a ternary value where one of the values means something 
   arch-dependent.

 - just rename the dang thing to "read_implies_exec" and be done with it?

Hmm? Wouldn't that make a lot more sense?

And if you want to split things up, there's at least three flags there:  
"stack" vs "file mapping" vs "anonymous mapping". For example, it might
well make sense to enforce PROT_EXEC on real file mappings, but not on the
stack or heap..  So "read_implies_exec" might well be a collection of bits 
to enable these one by one (and make the "legacy app" thing make it enable 
read-implies-exec for all the cases).

		Linus
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