Author: simon Date: Fri Oct 2 17:58:47 2009 New Revision: 197714 URL: http://svn.freebsd.org/changeset/base/197714
Log: MFC r197711: Add no zero mapping feature. NOTE: Unlike in the other branches where this change will be "merged" to, the 'no zero mapping' is enabled by default in stable/8. Errata: FreeBSD-EN-09:05.null Approved by: re (kib) Modified: stable/8/sys/ (props changed) stable/8/sys/amd64/include/xen/ (props changed) stable/8/sys/cddl/contrib/opensolaris/ (props changed) stable/8/sys/contrib/dev/acpica/ (props changed) stable/8/sys/contrib/pf/ (props changed) stable/8/sys/dev/xen/xenpci/ (props changed) stable/8/sys/kern/init_main.c stable/8/sys/kern/kern_exec.c Modified: stable/8/sys/kern/init_main.c ============================================================================== --- stable/8/sys/kern/init_main.c Fri Oct 2 17:53:48 2009 (r197713) +++ stable/8/sys/kern/init_main.c Fri Oct 2 17:58:47 2009 (r197714) @@ -492,6 +492,11 @@ proc0_init(void *dummy __unused) pmap_pinit0(vmspace_pmap(&vmspace0)); p->p_vmspace = &vmspace0; vmspace0.vm_refcnt = 1; + + /* + * proc0 is not expected to enter usermode, so there is no special + * handling for sv_minuser here, like is done for exec_new_vmspace(). + */ vm_map_init(&vmspace0.vm_map, p->p_sysent->sv_minuser, p->p_sysent->sv_maxuser); vmspace0.vm_map.pmap = vmspace_pmap(&vmspace0); Modified: stable/8/sys/kern/kern_exec.c ============================================================================== --- stable/8/sys/kern/kern_exec.c Fri Oct 2 17:53:48 2009 (r197713) +++ stable/8/sys/kern/kern_exec.c Fri Oct 2 17:58:47 2009 (r197714) @@ -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 = 0; +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) { @@ -999,7 +1004,7 @@ 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; @@ -1015,13 +1020,17 @@ 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; _______________________________________________ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"