From: deraadt <deraadt@openbsd.org>
Date: Sun, 21 Jan 2024 00:23:29 +0000 (+0000)
Subject: some bizzare glitch related to ramdisk instbin static binaries, their
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=c6f8eb87e480ffbeb43bedb5f5677b132ecf6b7a;p=openbsd

some bizzare glitch related to ramdisk instbin static binaries, their
mutable mapping is not working right, so temporarily bring back the
RW -> R *only* for ramdisk kernels
---

diff --git a/sys/uvm/uvm_map.c b/sys/uvm/uvm_map.c
index 5078f3a229d..c877457db64 100644
--- a/sys/uvm/uvm_map.c
+++ b/sys/uvm/uvm_map.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: uvm_map.c,v 1.321 2024/01/20 13:19:39 deraadt Exp $	*/
+/*	$OpenBSD: uvm_map.c,v 1.322 2024/01/21 00:23:29 deraadt Exp $	*/
 /*	$NetBSD: uvm_map.c,v 1.86 2000/11/27 08:40:03 chs Exp $	*/
 
 /*
@@ -3145,8 +3145,17 @@ uvm_map_protect(struct vm_map *map, vaddr_t start, vaddr_t end,
 			continue;
 
 		if (checkimmutable && (iter->etype & UVM_ET_IMMUTABLE)) {
-			error = EPERM;
-			goto out;
+#ifdef SMALL_KERNEL
+			if (iter->protection == (PROT_READ | PROT_WRITE) &&
+			    new_prot == PROT_READ) {
+				/* Permit RW to R as a data-locking mechanism */
+				goto ok;
+			} else
+#endif
+			{
+				error = EPERM;
+				goto out;
+			}
 		}
 		old_prot = iter->protection;
 		if (old_prot == PROT_NONE && new_prot != old_prot) {