lkml.org 
[lkml]   [2006]   [Jun]   [30]   [last100]   RSS Feed
Views: [more markup]  [less markup]  [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: make PROT_WRITE imply PROT_READ
FromArjan van de Ven <>
DateFri, 30 Jun 2006 10:35:45 +0200
On Thu, 2006-06-29 at 20:48 -0700, Ulrich Drepper wrote:
> On 6/29/06, Arjan van de Ven <arjan@infradead.org> wrote:
> > the thing is.. you can say EXACTLY the same about PROT_EXEC.. not all
> > processors support enforcing that.. so should we just always imply
> > PROT_EXEC as well?
> 
> There is a fundamental difference: not setting PROT_EXEC has no
> negative side effects.  You might be able to execute code and it just
> works.
> 
> With PROT_READ this is not the case, there _are_ side effects which are visible.

there are side effects which are visible with PROT_EXEC too, and even
the same kind...

with PROT_READ you may read even if you didn't specify it
with PROT_EXEC you may execute even if you didn't specifiy it

apps like JVM's forgot PROT_EXEC and break when the hardware enforces it
apps that forget PROT_READ break when the kernel/hardware enforce it

not too much difference....

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-06-30 10:38    [from the cache]
©2003-2008