From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753250AbaKRAQW (ORCPT ); Mon, 17 Nov 2014 19:16:22 -0500 Received: from smtp.outflux.net ([198.145.64.163]:34837 "EHLO smtp.outflux.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752695AbaKRAQV (ORCPT ); Mon, 17 Nov 2014 19:16:21 -0500 Date: Mon, 17 Nov 2014 16:16:04 -0800 From: Kees Cook To: Ingo Molnar Cc: Markus Trippelsdorf , Junjie Mao , Thomas Gleixner , "H. Peter Anvin" , x86@kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] x86, kaslr: handle Gold linker for finding bss+brk Message-ID: <20141118001604.GA25045@www.outflux.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-HELO: www.outflux.net Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When building with the Gold linker, the .bss and .brk areas of vmlinux are shown as consecutive instead of having the same file offset. Allow for either state, as long as things add up correctly. Fixes: e6023367d779 ("x86, kaslr: Prevent .bss from overlaping initrd") Reported-by: Markus Trippelsdorf Signed-off-by: Kees Cook Cc: Junjie Mao --- arch/x86/tools/calc_run_size.pl | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/arch/x86/tools/calc_run_size.pl b/arch/x86/tools/calc_run_size.pl index 0b0b124d3ece..23210baade2d 100644 --- a/arch/x86/tools/calc_run_size.pl +++ b/arch/x86/tools/calc_run_size.pl @@ -19,7 +19,16 @@ while (<>) { if ($file_offset == 0) { $file_offset = $offset; } elsif ($file_offset != $offset) { - die ".bss and .brk lack common file offset\n"; + # BFD linker shows the same file offset in ELF. + # Gold linker shows them as consecutive. + next if ($file_offset + $mem_size == $offset + $size); + + printf STDERR "file_offset: 0x%lx\n", $file_offset; + printf STDERR "mem_size: 0x%lx\n", $mem_size; + printf STDERR "offset: 0x%lx\n", $offset; + printf STDERR "size: 0x%lx\n", $size; + + die ".bss and .brk are non-contiguous\n"; } } } -- 1.9.1 -- Kees Cook Chrome OS Security