From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751890AbdAYVHF (ORCPT ); Wed, 25 Jan 2017 16:07:05 -0500 Received: from mail.kernel.org ([198.145.29.136]:58326 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751254AbdAYVHD (ORCPT ); Wed, 25 Jan 2017 16:07:03 -0500 From: Andy Lutomirski To: security@kernel.org Cc: Konstantin Khlebnikov , Alexander Viro , Kees Cook , Willy Tarreau , "linux-mm@kvack.org" , Andrew Morton , yalin wang , Linux Kernel Mailing List , Jan Kara , Linux FS Devel , Andy Lutomirski Subject: [PATCH 0/2] setgid hardening Date: Wed, 25 Jan 2017 13:06:50 -0800 Message-Id: X-Mailer: git-send-email 2.9.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The kernel has some dangerous behavior involving the creation and modification of setgid executables. These issues aren't kernel security bugs per se, but they have been used to turn various filesystem permission oddities into reliably privilege escalation exploits. See http://www.halfdog.net/Security/2015/SetgidDirectoryPrivilegeEscalation/ for a nice writeup. Let's fix them for real. Andy Lutomirski (2): fs: Check f_cred instead of current's creds in should_remove_suid() fs: Harden against open(..., O_CREAT, 02777) in a setgid directory fs/inode.c | 37 ++++++++++++++++++++++++++++++------- fs/internal.h | 2 +- fs/ocfs2/file.c | 4 ++-- fs/open.c | 2 +- include/linux/fs.h | 2 +- 5 files changed, 35 insertions(+), 12 deletions(-) -- 2.9.3 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Andy Lutomirski To: security@kernel.org Cc: Konstantin Khlebnikov , Alexander Viro , Kees Cook , Willy Tarreau , "linux-mm@kvack.org" , Andrew Morton , yalin wang , Linux Kernel Mailing List , Jan Kara , Linux FS Devel , Andy Lutomirski Subject: [PATCH 0/2] setgid hardening Date: Wed, 25 Jan 2017 13:06:50 -0800 Message-Id: Sender: owner-linux-mm@kvack.org List-ID: The kernel has some dangerous behavior involving the creation and modification of setgid executables. These issues aren't kernel security bugs per se, but they have been used to turn various filesystem permission oddities into reliably privilege escalation exploits. See http://www.halfdog.net/Security/2015/SetgidDirectoryPrivilegeEscalation/ for a nice writeup. Let's fix them for real. Andy Lutomirski (2): fs: Check f_cred instead of current's creds in should_remove_suid() fs: Harden against open(..., O_CREAT, 02777) in a setgid directory fs/inode.c | 37 ++++++++++++++++++++++++++++++------- fs/internal.h | 2 +- fs/ocfs2/file.c | 4 ++-- fs/open.c | 2 +- include/linux/fs.h | 2 +- 5 files changed, 35 insertions(+), 12 deletions(-) -- 2.9.3 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org