linux-kernel - [PATCH 3.16.y-ckt 036/168] x86, kaslr: Handle Gold linker for finding bss/brk

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 15 Dec 2014 14:24:50 +0000
From:	Luis Henriques <luis.henriques@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Kees Cook <keescook@...omium.org>,
	Junjie Mao <eternal.n08@...il.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Luis Henriques <luis.henriques@...onical.com>
Subject: [PATCH 3.16.y-ckt 036/168] x86, kaslr: Handle Gold linker for finding bss/brk

3.16.7-ckt3 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Kees Cook <keescook@...omium.org>

commit 70b61e362187b5fccac206506d402f3424e3e749 upstream.

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 <markus@...ppelsdorf.de>
Signed-off-by: Kees Cook <keescook@...omium.org>
Cc: Junjie Mao <eternal.n08@...il.com>
Link: http://lkml.kernel.org/r/20141118001604.GA25045@www.outflux.net
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Luis Henriques <luis.henriques@...onical.com>
---
 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";
 		}
 	}
 }
-- 
2.1.3

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