From 6bffaeed6b38758ab18441db1c3bb407d06553de Mon Sep 17 00:00:00 2001
From: deraadt <deraadt@openbsd.org>
Date: Sun, 21 Jan 2024 16:59:15 +0000
Subject: [PATCH] For minherit(MAP_INHERIT_ZERO) upon readonly memory return
 EPERM. ok kettenis

---
 sys/uvm/uvm_map.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/sys/uvm/uvm_map.c b/sys/uvm/uvm_map.c
index 0cc03de7331..34c37cc0d2e 100644
--- a/sys/uvm/uvm_map.c
+++ b/sys/uvm/uvm_map.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_map.c,v 1.324 2024/01/21 16:57:06 deraadt Exp $	*/
+/*	$OpenBSD: uvm_map.c,v 1.325 2024/01/21 16:59:15 deraadt Exp $	*/
 /*	$NetBSD: uvm_map.c,v 1.86 2000/11/27 08:40:03 chs Exp $	*/
 
 /*
@@ -4199,6 +4199,9 @@ uvm_map_inherit(struct vm_map *map, vaddr_t start, vaddr_t end,
 	while (entry1 != NULL && entry1->start < end) {
 		if (entry1->etype & UVM_ET_IMMUTABLE)
 			goto out;
+		if (new_inheritance == MAP_INHERIT_ZERO &&
+		    (entry1->protection & PROT_WRITE) == 0)
+			goto out;
 		entry1 = RBT_NEXT(uvm_map_addr, entry1);
 	}
 
-- 
2.20.1