From owner-svn-src-all@freebsd.org Fri Dec 18 16:33:17 2015 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 16E24A4C5FC; Fri, 18 Dec 2015 16:33:17 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::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 C4EA41B19; Fri, 18 Dec 2015 16:33:16 +0000 (UTC) (envelope-from mjg@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id tBIGXFR7046685; Fri, 18 Dec 2015 16:33:15 GMT (envelope-from mjg@FreeBSD.org) Received: (from mjg@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id tBIGXFff046683; Fri, 18 Dec 2015 16:33:15 GMT (envelope-from mjg@FreeBSD.org) Message-Id: <201512181633.tBIGXFff046683@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: mjg set sender to mjg@FreeBSD.org using -f From: Mateusz Guzik Date: Fri, 18 Dec 2015 16:33:15 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r292440 - in head/sys: kern sys 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: 2.1.20 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: Fri, 18 Dec 2015 16:33:17 -0000 Author: mjg Date: Fri Dec 18 16:33:15 2015 New Revision: 292440 URL: https://svnweb.freebsd.org/changeset/base/292440 Log: proc: fix a race which could result in dereference of bad p_pgrp pointer on fork During fork p_starcopy - p_endcopy area of a process is populated with bcopy with only proc lock held. Another forking thread can find such a process and proceed to access p_pgrp included in said area. Fix the problem by moving the field outside. It is being properly assigned later. Reviewed by: kib Diagnosed by: kib Tested by: Fabian Keil MFC after: 10 days Modified: head/sys/kern/kern_proc.c head/sys/sys/proc.h Modified: head/sys/kern/kern_proc.c ============================================================================== --- head/sys/kern/kern_proc.c Fri Dec 18 14:56:49 2015 (r292439) +++ head/sys/kern/kern_proc.c Fri Dec 18 16:33:15 2015 (r292440) @@ -248,6 +248,7 @@ proc_init(void *mem, int size, int flags TAILQ_INIT(&p->p_threads); /* all threads in proc */ EVENTHANDLER_INVOKE(process_init, p); p->p_stats = pstats_alloc(); + p->p_pgrp = NULL; SDT_PROBE3(proc, , init, return, p, size, flags); return (0); } Modified: head/sys/sys/proc.h ============================================================================== --- head/sys/sys/proc.h Fri Dec 18 14:56:49 2015 (r292439) +++ head/sys/sys/proc.h Fri Dec 18 16:33:15 2015 (r292440) @@ -586,7 +586,6 @@ struct proc { int p_osrel; /* (x) osreldate for the binary (from ELF note, if any) */ char p_comm[MAXCOMLEN + 1]; /* (b) Process name. */ - struct pgrp *p_pgrp; /* (c + e) Pointer to process group. */ struct sysentvec *p_sysent; /* (b) Syscall dispatch info. */ struct pargs *p_args; /* (c) Process arguments. */ rlim_t p_cpulimit; /* (c) Current CPU limit in seconds. */ @@ -599,6 +598,7 @@ struct proc { u_int p_xsig; /* (c) Stop/kill sig. */ /* End area that is copied on creation. */ #define p_endcopy p_xsig + struct pgrp *p_pgrp; /* (c + e) Pointer to process group. */ struct knlist p_klist; /* (c) Knotes attached to this proc. */ int p_numthreads; /* (c) Number of threads. */ struct mdproc p_md; /* Any machine-dependent fields. */