lkml.org 
[lkml]   [2006]   [Sep]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch] remove MNT_NOEXEC check for PROT_EXEC MAP_PRIVATE mmaps
Hello.

Hugh Dickins wrote:
> since executables are typically mapped MAP_PRIVATE, I suspect
> your patch will simply break mmap's intended MNT_NOEXEC check.
The one with ld.so you mean? But its a user-space issue,
I haven't seen anyone claiming the opposite (and you even
explicitly confirmed it is).

> I think you need to face up to the fact that "noexec"
> doesn't suit your mount, and just leave it at that.
But noone have answered this question:
Which configuration is more secure - the one where all
the user-writable fs are mounted with "noexec" (in old
sense of noexec), or the one without "noexec" at all
because I should no longer use it here and there (actually,
everywhere)?

> But I do concede that I'm reluctant to present that patch Alan
> encouraged, adding a matching MNT_NOEXEC check to mprotect: it
> would be consistent, and I do like consistency, but in this case
> fear that change in behaviour may cause new userspace breakage.
I can't think of a single real-life example where it will
break something over whatever is broken already by the mmap
check. But I am not encouraging such a change of course.

-
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: 2006-09-28 06:35    [W:0.113 / U:0.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site