The signal trampoline and timekeep regions can be marked immutable at

execve() time
ok kettenis

diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c
index 761441c..af474ee 100644 (file)
--- a/sys/kern/kern_exec.c
+++ b/sys/kern/kern_exec.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: kern_exec.c,v 1.232 2022/10/07 14:59:39 deraadt Exp $ */
+/*     $OpenBSD: kern_exec.c,v 1.233 2022/10/08 16:58:34 deraadt Exp $ */
 /*     $NetBSD: kern_exec.c,v 1.75 1996/02/09 18:59:28 christos Exp $  */
 
 /*-
@@ -863,6 +863,8 @@ exec_sigcode_map(struct process *pr)
                uao_detach(sigobject);
                return (ENOMEM);
        }
+       uvm_map_immutable(&pr->ps_vmspace->vm_map, pr->ps_sigcode,
+           pr->ps_sigcode + round_page(sz), 1, "sig");
 
        /* Calculate PC at point of sigreturn entry */
        pr->ps_sigcoderet = pr->ps_sigcode + (sigcoderet - sigcode);
@@ -911,6 +913,8 @@ exec_timekeep_map(struct process *pr)
                uao_detach(timekeep_object);
                return (ENOMEM);
        }
+       uvm_map_immutable(&pr->ps_vmspace->vm_map, pr->ps_timekeep,
+           pr->ps_timekeep + timekeep_sz, 1, "time");
 
        return (0);
 }