From 22647093664a33f48caa6dc481ecead248f3e9f1 Mon Sep 17 00:00:00 2001
From: dv <dv@openbsd.org>
Date: Sun, 2 Apr 2023 02:04:10 +0000
Subject: [PATCH] vmd(8): migrate vmd_vm.vm_ttyname to char array.

Other structs use a fixed length array already. This allows a vmd_vm
object to be transmitted over an ipc channel, too.

Additionally, solves a segfault caused by a strlcpy(3) in an error
path.

ok mlarkin@
---
 usr.sbin/vmd/config.c |  6 +++---
 usr.sbin/vmd/vmd.c    | 13 +++++++------
 usr.sbin/vmd/vmd.h    |  4 ++--
 3 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/usr.sbin/vmd/config.c b/usr.sbin/vmd/config.c
index 922e6cccd65..cc88551b63e 100644
--- a/usr.sbin/vmd/config.c
+++ b/usr.sbin/vmd/config.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: config.c,v 1.68 2023/02/22 10:04:45 mbuhl Exp $	*/
+/*	$OpenBSD: config.c,v 1.69 2023/04/02 02:04:10 dv Exp $	*/
 
 /*
  * Copyright (c) 2015 Reyk Floeter <reyk@openbsd.org>
@@ -451,10 +451,10 @@ config_setvm(struct privsep *ps, struct vmd_vm *vm, uint32_t peerid, uid_t uid)
 	}
 
 	/* Open TTY */
-	if (vm->vm_ttyname == NULL) {
+	if (vm->vm_ttyname[0] == '\0') {
 		if (vm_opentty(vm) == -1) {
 			log_warn("%s: can't open tty %s", __func__,
-			    vm->vm_ttyname == NULL ? "" : vm->vm_ttyname);
+			    vm->vm_ttyname[0] == '\0' ? "" : vm->vm_ttyname);
 			goto fail;
 		}
 	}
diff --git a/usr.sbin/vmd/vmd.c b/usr.sbin/vmd/vmd.c
index f604282ddaf..75af37a29a6 100644
--- a/usr.sbin/vmd/vmd.c
+++ b/usr.sbin/vmd/vmd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vmd.c,v 1.138 2023/01/28 14:40:53 dv Exp $	*/
+/*	$OpenBSD: vmd.c,v 1.139 2023/04/02 02:04:10 dv Exp $	*/
 
 /*
  * Copyright (c) 2015 Reyk Floeter <reyk@openbsd.org>
@@ -489,7 +489,7 @@ vmd_dispatch_vmm(int fd, struct privsep_proc *p, struct imsg *imsg)
 		memcpy(&vir, imsg->data, sizeof(vir));
 		if ((vm = vm_getbyvmid(vir.vir_info.vir_id)) != NULL) {
 			memset(vir.vir_ttyname, 0, sizeof(vir.vir_ttyname));
-			if (vm->vm_ttyname != NULL)
+			if (vm->vm_ttyname[0] != '\0')
 				strlcpy(vir.vir_ttyname, vm->vm_ttyname,
 				    sizeof(vir.vir_ttyname));
 			log_debug("%s: running vm: %d, vm_state: 0x%x",
@@ -1789,8 +1789,11 @@ vm_opentty(struct vmd_vm *vm)
 
 	vm->vm_tty = ptm.cfd;
 	close(ptm.sfd);
-	if ((vm->vm_ttyname = strdup(ptm.sn)) == NULL)
+	if (strlcpy(vm->vm_ttyname, ptm.sn, sizeof(vm->vm_ttyname))
+	    >= sizeof(vm->vm_ttyname)) {
+		log_warnx("%s: truncated ttyname", __func__);
 		goto fail;
+	}
 
 	uid = vm->vm_uid;
 	gid = vm->vm_params.vmc_owner.gid;
@@ -1858,8 +1861,7 @@ vm_closetty(struct vmd_vm *vm)
 		close(vm->vm_tty);
 		vm->vm_tty = -1;
 	}
-	free(vm->vm_ttyname);
-	vm->vm_ttyname = NULL;
+	memset(&vm->vm_ttyname, 0, sizeof(vm->vm_ttyname));
 }
 
 void
@@ -1954,4 +1956,3 @@ vm_terminate(struct vmd_vm *vm, const char *caller)
 		vm_remove(vm, caller);
 	}
 }
-
diff --git a/usr.sbin/vmd/vmd.h b/usr.sbin/vmd/vmd.h
index d04c28fb204..7bbbf62734b 100644
--- a/usr.sbin/vmd/vmd.h
+++ b/usr.sbin/vmd/vmd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vmd.h,v 1.114 2023/01/28 14:40:53 dv Exp $	*/
+/*	$OpenBSD: vmd.h,v 1.115 2023/04/02 02:04:10 dv Exp $	*/
 
 /*
  * Copyright (c) 2015 Mike Larkin <mlarkin@openbsd.org>
@@ -286,7 +286,7 @@ struct vmd_vm {
 	int			 vm_cdrom;
 	int			 vm_disks[VM_MAX_DISKS_PER_VM][VM_MAX_BASE_PER_DISK];
 	struct vmd_if		 vm_ifs[VM_MAX_NICS_PER_VM];
-	char			*vm_ttyname;
+	char			 vm_ttyname[VM_TTYNAME_MAX];
 	int			 vm_tty;
 	uint32_t		 vm_peerid;
 	/* When set, VM was defined in a config file */
-- 
2.20.1