From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f198.google.com (mail-qk0-f198.google.com [209.85.220.198]) by kanga.kvack.org (Postfix) with ESMTP id BD4296B0033 for ; Mon, 30 Jan 2017 22:49:59 -0500 (EST) Received: by mail-qk0-f198.google.com with SMTP id z68so7261908qkc.5 for ; Mon, 30 Jan 2017 19:49:59 -0800 (PST) Received: from mail-qk0-x242.google.com (mail-qk0-x242.google.com. [2607:f8b0:400d:c09::242]) by mx.google.com with ESMTPS id d12si11042962qtg.321.2017.01.30.19.49.58 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 30 Jan 2017 19:49:58 -0800 (PST) Received: by mail-qk0-x242.google.com with SMTP id 11so21939022qkl.0 for ; Mon, 30 Jan 2017 19:49:58 -0800 (PST) MIME-Version: 1.0 In-Reply-To: References: From: Michael Kerrisk Date: Tue, 31 Jan 2017 16:49:37 +1300 Message-ID: Subject: Re: [PATCH v2 0/2] setgid hardening Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Andy Lutomirski Cc: security@kernel.org, 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 , Frank Filz , Linux API [CC += linux-api@] Andy, this is an API change! On Sat, Jan 28, 2017 at 3:49 PM, Andy Lutomirski wrote: > 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. > > Changes from v1: > - Fix uninitialized variable issue (Willy, Ben) > - Also check current creds in should_remove_suid() (Ben) > > Andy Lutomirski (2): > fs: Check f_cred as well as of current's creds in should_remove_suid() > fs: Harden against open(..., O_CREAT, 02777) in a setgid directory > > fs/inode.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++-------- > fs/internal.h | 2 +- > fs/ocfs2/file.c | 4 ++-- > fs/open.c | 2 +- > include/linux/fs.h | 2 +- > 5 files changed, 57 insertions(+), 14 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 -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Author of "The Linux Programming Interface", http://blog.man7.org/ -- 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