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Date:      Fri, 2 Oct 2009 18:09:56 +0000 (UTC)
From:      "Simon L. Nielsen" <simon@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-7@freebsd.org
Subject:   svn commit: r197715 - releng/6.3 releng/6.3/sys/conf releng/6.3/sys/fs/devfs releng/6.3/sys/kern releng/6.3/sys/sys releng/6.4 releng/6.4/sys/conf releng/6.4/sys/fs/devfs releng/6.4/sys/kern releng...
Message-ID:  <200910021809.n92I9u1r009085@svn.freebsd.org>
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Author: simon
Date: Fri Oct  2 18:09:56 2009
New Revision: 197715
URL: http://svn.freebsd.org/changeset/base/197715

Log:
  MFC r197711 (partial) to 6.x and 7.x:
  
  - Add no zero mapping feature, disabled by default. [EN-09:05]
  
  MFC 178913,178914,179242,179243,180336,180340 to 6.x:
  
  - Fix kqueue pipe race conditions. [SA-09:13]
  
  MFC r192301 to 7.x; 6.x has slightly different fix:
  
  - Fix devfs / VFS NULL pointer race condition. [SA-09:14]
  
  Security:	FreeBSD-SA-09:13.pipe
  Security:	FreeBSD-SA-09:14.devfs
  Errata:		FreeBSD-EN-09:05.null
  Submitted by:	kib [SA-09:13] [SA-09:14]
  Submitted by:	bz [EN-09:05]
  In collaboration with:	jhb, kib, alc [EN-09:05]
  Approved by:	so (simon)

Modified:
  stable/7/sys/kern/kern_exec.c

Changes in other areas also in this revision:
Modified:
  releng/6.3/UPDATING
  releng/6.3/sys/conf/newvers.sh
  releng/6.3/sys/fs/devfs/devfs_vnops.c
  releng/6.3/sys/kern/kern_event.c
  releng/6.3/sys/kern/kern_exec.c
  releng/6.3/sys/kern/kern_fork.c
  releng/6.3/sys/kern/sys_pipe.c
  releng/6.3/sys/sys/event.h
  releng/6.3/sys/sys/pipe.h
  releng/6.4/UPDATING
  releng/6.4/sys/conf/newvers.sh
  releng/6.4/sys/fs/devfs/devfs_vnops.c
  releng/6.4/sys/kern/kern_event.c
  releng/6.4/sys/kern/kern_exec.c
  releng/6.4/sys/kern/kern_fork.c
  releng/6.4/sys/kern/sys_pipe.c
  releng/6.4/sys/sys/event.h
  releng/6.4/sys/sys/pipe.h
  releng/7.1/UPDATING
  releng/7.1/sys/conf/newvers.sh
  releng/7.1/sys/fs/devfs/devfs_vnops.c
  releng/7.1/sys/kern/kern_exec.c
  releng/7.2/UPDATING
  releng/7.2/sys/conf/newvers.sh
  releng/7.2/sys/fs/devfs/devfs_vnops.c
  releng/7.2/sys/kern/kern_exec.c
  stable/6/sys/fs/devfs/devfs_vnops.c
  stable/6/sys/kern/kern_event.c
  stable/6/sys/kern/kern_exec.c
  stable/6/sys/kern/kern_fork.c
  stable/6/sys/kern/sys_pipe.c
  stable/6/sys/sys/event.h
  stable/6/sys/sys/pipe.h

Modified: stable/7/sys/kern/kern_exec.c
==============================================================================
--- stable/7/sys/kern/kern_exec.c	Fri Oct  2 17:58:47 2009	(r197714)
+++ stable/7/sys/kern/kern_exec.c	Fri Oct  2 18:09:56 2009	(r197715)
@@ -122,6 +122,11 @@ u_long ps_arg_cache_limit = PAGE_SIZE / 
 SYSCTL_ULONG(_kern, OID_AUTO, ps_arg_cache_limit, CTLFLAG_RW, 
     &ps_arg_cache_limit, 0, "");
 
+static int map_at_zero = 1;
+TUNABLE_INT("security.bsd.map_at_zero", &map_at_zero);
+SYSCTL_INT(_security_bsd, OID_AUTO, map_at_zero, CTLFLAG_RW, &map_at_zero, 0,
+    "Permit processes to map an object at virtual address 0.");
+
 static int
 sysctl_kern_ps_strings(SYSCTL_HANDLER_ARGS)
 {
@@ -939,7 +944,7 @@ exec_new_vmspace(imgp, sv)
 	int error;
 	struct proc *p = imgp->proc;
 	struct vmspace *vmspace = p->p_vmspace;
-	vm_offset_t stack_addr;
+	vm_offset_t sv_minuser, stack_addr;
 	vm_map_t map;
 	u_long ssiz;
 
@@ -955,13 +960,17 @@ exec_new_vmspace(imgp, sv)
 	 * not disrupted
 	 */
 	map = &vmspace->vm_map;
-	if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv->sv_minuser &&
+	if (map_at_zero)
+		sv_minuser = sv->sv_minuser;
+	else
+		sv_minuser = MAX(sv->sv_minuser, PAGE_SIZE);
+	if (vmspace->vm_refcnt == 1 && vm_map_min(map) == sv_minuser &&
 	    vm_map_max(map) == sv->sv_maxuser) {
 		shmexit(vmspace);
 		pmap_remove_pages(vmspace_pmap(vmspace));
 		vm_map_remove(map, vm_map_min(map), vm_map_max(map));
 	} else {
-		error = vmspace_exec(p, sv->sv_minuser, sv->sv_maxuser);
+		error = vmspace_exec(p, sv_minuser, sv->sv_maxuser);
 		if (error)
 			return (error);
 		vmspace = p->p_vmspace;

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