From: deraadt <deraadt@openbsd.org>
Date: Fri, 21 Oct 2022 18:11:55 +0000 (+0000)
Subject: sigaltstack() was adapted to work on mimmutable regions (an unfortunate
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=f2e49d373091b1b3b633aadd3ef904005fccbab6;p=openbsd

sigaltstack() was adapted to work on mimmutable regions (an unfortunate
compromise...), but it means the stack can be marked immutable again.
ok kettenis
---

diff --git a/sys/kern/exec_subr.c b/sys/kern/exec_subr.c
index dc4053a5f89..0cf207ae33f 100644
--- a/sys/kern/exec_subr.c
+++ b/sys/kern/exec_subr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: exec_subr.c,v 1.59 2022/10/21 18:10:56 deraadt Exp $	*/
+/*	$OpenBSD: exec_subr.c,v 1.60 2022/10/21 18:11:55 deraadt Exp $	*/
 /*	$NetBSD: exec_subr.c,v 1.9 1994/12/04 03:10:42 mycroft Exp $	*/
 
 /*
@@ -419,21 +419,21 @@ exec_setup_stack(struct proc *p, struct exec_package *epp)
 	 * <stack> ep_minsaddr
 	 */
 #ifdef MACHINE_STACK_GROWS_UP
-	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero,
+	NEW_VMCMD2(&epp->ep_vmcmds, vmcmd_map_zero,
 	    ((epp->ep_minsaddr - epp->ep_ssize) - epp->ep_maxsaddr),
-	    epp->ep_maxsaddr + epp->ep_ssize, NULLVP, 0,
-	    PROT_NONE);
+	    epp->ep_maxsaddr + epp->ep_ssize,
+	    NULLVP, 0, PROT_NONE,  VMCMD_IMMUTABLE);
 	NEW_VMCMD2(&epp->ep_vmcmds, vmcmd_map_zero, epp->ep_ssize,
-	    epp->ep_maxsaddr, NULLVP, 0,
-	    PROT_READ | PROT_WRITE, VMCMD_STACK);
+	    epp->ep_maxsaddr,
+	    NULLVP, 0, PROT_READ | PROT_WRITE, VMCMD_STACK | VMCMD_IMMUTABLE);
 #else
-	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero,
+	NEW_VMCMD2(&epp->ep_vmcmds, vmcmd_map_zero,
 	    ((epp->ep_minsaddr - epp->ep_ssize) - epp->ep_maxsaddr),
-	    epp->ep_maxsaddr, NULLVP, 0,
-	    PROT_NONE);
+	    epp->ep_maxsaddr,
+	    NULLVP, 0, PROT_NONE, VMCMD_IMMUTABLE);
 	NEW_VMCMD2(&epp->ep_vmcmds, vmcmd_map_zero, epp->ep_ssize,
-	    (epp->ep_minsaddr - epp->ep_ssize), NULLVP, 0,
-	    PROT_READ | PROT_WRITE, VMCMD_STACK);
+	    (epp->ep_minsaddr - epp->ep_ssize),
+	    NULLVP, 0, PROT_READ | PROT_WRITE, VMCMD_STACK | VMCMD_IMMUTABLE);
 #endif
 
 	return (0);
diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c
index 0e4ac0170fb..3b95c73bc8d 100644
--- a/sys/kern/kern_exec.c
+++ b/sys/kern/kern_exec.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_exec.c,v 1.235 2022/10/12 02:39:16 deraadt Exp $	*/
+/*	$OpenBSD: kern_exec.c,v 1.236 2022/10/21 18:11:55 deraadt Exp $	*/
 /*	$NetBSD: kern_exec.c,v 1.75 1996/02/09 18:59:28 christos Exp $	*/
 
 /*-
@@ -466,13 +466,13 @@ sys_execve(struct proc *p, void *v, register_t *retval)
 #ifdef MACHINE_STACK_GROWS_UP
 	pr->ps_strings = (vaddr_t)vm->vm_maxsaddr + sgap;
         if (uvm_map_protect(&vm->vm_map, (vaddr_t)vm->vm_maxsaddr,
-            trunc_page(pr->ps_strings), PROT_NONE, TRUE, TRUE))
+            trunc_page(pr->ps_strings), PROT_NONE, TRUE, FALSE))
                 goto exec_abort;
 #else
 	pr->ps_strings = (vaddr_t)vm->vm_minsaddr - sizeof(arginfo) - sgap;
         if (uvm_map_protect(&vm->vm_map,
             round_page(pr->ps_strings + sizeof(arginfo)),
-            (vaddr_t)vm->vm_minsaddr, PROT_NONE, TRUE, TRUE))
+            (vaddr_t)vm->vm_minsaddr, PROT_NONE, TRUE, FALSE))
                 goto exec_abort;
 #endif