Date: Fri, 20 Oct 2006 14:32:33 +0200
From: Marcus Meissner <meissner@suse.de>
To: Jesper Juhl <jesper.juhl@gmail.com>
Cc: Dave Jones <davej@redhat.com>, linux-kernel@vger.kernel.org, akpm@osdl.org,
       arjan@linux.intel.com
Subject: Re: [PATCH] binfmt_elf: randomize PIE binaries (2nd try)
Message-ID: <20061020123233.GA10093@suse.de>
References: <20061020115527.GB14448@suse.de> <9a8748490610200520j6d708a52p2f90effd4b8893d9@mail.gmail.com>
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On Fri, Oct 20, 2006 at 02:20:31PM +0200, Jesper Juhl wrote:
> On 20/10/06, Marcus Meissner <meissner@suse.de> wrote:
> >Randomizes -pie compiled binaries from PAGE_SIZE up to
> >ELF_ET_DYN_BASE.
> >
> >0 -> PAGE_SIZE is excluded to allow NULL ptr accesses
> >to fail.
> >
> >Signed-off-by: Marcus Meissner <meissner@suse.de>
> >
> >----
> > binfmt_elf.c |    8 +++++++-
> > 1 file changed, 7 insertions(+), 1 deletion(-)
> >
> >--- linux-2.6.18/fs/binfmt_elf.c.xx     2006-10-20 10:42:03.000000000 +0200
> >+++ linux-2.6.18/fs/binfmt_elf.c        2006-10-20 10:51:27.000000000 +0200
> >@@ -856,7 +856,13 @@
> >                         * default mmap base, as well as whatever program 
> >                         they
> >                         * might try to exec.  This is because the brk will
> >                         * follow the loader, and is not movable.  */
> >-                       load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr);
> >+                       if (current->flags & PF_RANDOMIZE)
> >+                               load_bias = randomize_range(PAGE_SIZE,
> >+                                                           
> >ELF_ET_DYN_BASE,
> >+                                                           0);
> 
> How about putting the two lines above on one line?  ^^^^^

My editor said it would end at column 80. Starting from 0 it would col 79
actually, but I did not want to risk it.

Ciao, Marcus
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