From owner-svn-src-all@FreeBSD.ORG Wed Jul 9 21:39:41 2014 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 039CBDA5; Wed, 9 Jul 2014 21:39:41 +0000 (UTC) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id E4CFD2D49; Wed, 9 Jul 2014 21:39:40 +0000 (UTC) Received: from svn.freebsd.org ([127.0.1.70]) by svn.freebsd.org (8.14.8/8.14.8) with ESMTP id s69Ldelv037803; Wed, 9 Jul 2014 21:39:40 GMT (envelope-from kib@svn.freebsd.org) Received: (from kib@localhost) by svn.freebsd.org (8.14.8/8.14.8/Submit) id s69LdeRb037802; Wed, 9 Jul 2014 21:39:40 GMT (envelope-from kib@svn.freebsd.org) Message-Id: <201407092139.s69LdeRb037802@svn.freebsd.org> From: Konstantin Belousov Date: Wed, 9 Jul 2014 21:39:40 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r268471 - head/sys/amd64/amd64 X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 09 Jul 2014 21:39:41 -0000 Author: kib Date: Wed Jul 9 21:39:40 2014 New Revision: 268471 URL: http://svnweb.freebsd.org/changeset/base/268471 Log: For safety, ensure that any consumer of the set_regs() and ptrace_set_pc() use the correct return to userspace using iret. The signal return, PT_CONTINUE (which in fact uses signal return path) set the pcb flag already. The setcontext(2) enforces iret return when %rip is incorrect. Due to this, the change is redundand, but is made to ensure that no path which modifies context, forgets to set PCB_FULL_IRET. Inspired by: CVE-2014-4699 Reviewed by: jhb Sponsored by: The FreeBSD Foundation MFC after: 1 week Modified: head/sys/amd64/amd64/machdep.c Modified: head/sys/amd64/amd64/machdep.c ============================================================================== --- head/sys/amd64/amd64/machdep.c Wed Jul 9 21:07:20 2014 (r268470) +++ head/sys/amd64/amd64/machdep.c Wed Jul 9 21:39:40 2014 (r268471) @@ -2144,7 +2144,9 @@ makectx(struct trapframe *tf, struct pcb int ptrace_set_pc(struct thread *td, unsigned long addr) { + td->td_frame->tf_rip = addr; + set_pcb_flags(td->td_pcb, PCB_FULL_IRET); return (0); } @@ -2244,8 +2246,8 @@ set_regs(struct thread *td, struct reg * tp->tf_fs = regs->r_fs; tp->tf_gs = regs->r_gs; tp->tf_flags = TF_HASSEGS; - set_pcb_flags(td->td_pcb, PCB_FULL_IRET); } + set_pcb_flags(td->td_pcb, PCB_FULL_IRET); return (0); }