From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:34564 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932103AbeAXNl2 (ORCPT ); Wed, 24 Jan 2018 08:41:28 -0500 Subject: Patch "fs/fcntl: f_setown, avoid undefined behaviour" has been added to the 3.18-stable tree To: jslaby@suse.cz, bfields@fieldses.org, gregkh@linuxfoundation.org, jlayton@poochiereds.net, jlayton@redhat.com, viro@zeniv.linux.org.uk Cc: , From: Date: Wed, 24 Jan 2018 14:41:26 +0100 Message-ID: <151680128610373@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled fs/fcntl: f_setown, avoid undefined behaviour to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: fs-fcntl-f_setown-avoid-undefined-behaviour.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From fc3dc67471461c0efcb1ed22fb7595121d65fad9 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Tue, 13 Jun 2017 13:35:51 +0200 Subject: fs/fcntl: f_setown, avoid undefined behaviour From: Jiri Slaby commit fc3dc67471461c0efcb1ed22fb7595121d65fad9 upstream. fcntl(0, F_SETOWN, 0x80000000) triggers: UBSAN: Undefined behaviour in fs/fcntl.c:118:7 negation of -2147483648 cannot be represented in type 'int': CPU: 1 PID: 18261 Comm: syz-executor Not tainted 4.8.1-0-syzkaller #1 ... Call Trace: ... [] ? f_setown+0x1d8/0x200 [] ? SyS_fcntl+0x999/0xf30 [] ? entry_SYSCALL_64_fastpath+0x23/0xc1 Fix that by checking the arg parameter properly (against INT_MAX) before "who = -who". And return immediatelly with -EINVAL in case it is wrong. Note that according to POSIX we can return EINVAL: http://pubs.opengroup.org/onlinepubs/9699919799/functions/fcntl.html [EINVAL] The cmd argument is F_SETOWN and the value of the argument is not valid as a process or process group identifier. [v2] returns an error, v1 used to fail silently [v3] implement proper check for the bad value INT_MIN Signed-off-by: Jiri Slaby Cc: Jeff Layton Cc: "J. Bruce Fields" Cc: Alexander Viro Cc: linux-fsdevel@vger.kernel.org Signed-off-by: Jeff Layton Signed-off-by: Greg Kroah-Hartman --- fs/fcntl.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -113,6 +113,10 @@ void f_setown(struct file *filp, unsigne int who = arg; type = PIDTYPE_PID; if (who < 0) { + /* avoid overflow below */ + if (who == INT_MIN) + return -EINVAL; + type = PIDTYPE_PGID; who = -who; } Patches currently in stable-queue which might be from jslaby@suse.cz are queue-3.18/ipc-msg-make-msgrcv-work-with-long_min.patch queue-3.18/fs-fcntl-f_setown-avoid-undefined-behaviour.patch