From e4c12d7a863e1916b1a171487174679e25ab965c Mon Sep 17 00:00:00 2001
From: bluhm <bluhm@openbsd.org>
Date: Fri, 3 Sep 2021 16:28:33 +0000
Subject: [PATCH] Use a define for the iov array size in syslogd.  This is
 better than passing the magic number 6 around and checking at runtime whether
 its fits. OK deraadt@ martijn@ mvs@

---
 usr.sbin/syslogd/syslogd.c | 11 +++++------
 usr.sbin/syslogd/syslogd.h |  6 ++++--
 usr.sbin/syslogd/ttymsg.c  | 16 ++++------------
 3 files changed, 13 insertions(+), 20 deletions(-)

diff --git a/usr.sbin/syslogd/syslogd.c b/usr.sbin/syslogd/syslogd.c
index a7c1e505c6c..8632f29bc25 100644
--- a/usr.sbin/syslogd/syslogd.c
+++ b/usr.sbin/syslogd/syslogd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: syslogd.c,v 1.266 2021/07/14 13:33:57 kn Exp $	*/
+/*	$OpenBSD: syslogd.c,v 1.267 2021/09/03 16:28:33 bluhm Exp $	*/
 
 /*
  * Copyright (c) 2014-2017 Alexander Bluhm <bluhm@genua.de>
@@ -1895,8 +1895,7 @@ logline(int pri, int flags, char *from, char *msg)
 void
 fprintlog(struct filed *f, int flags, char *msg)
 {
-	struct iovec iov[6];
-	struct iovec *v;
+	struct iovec iov[IOVCNT], *v;
 	int l, retryonce;
 	char line[LOG_MAXLINE + 1], repbuf[80], greetings[500];
 	char ebuf[ERRBUFSIZE];
@@ -2072,7 +2071,7 @@ fprintlog(struct filed *f, int flags, char *msg)
 		}
 		retryonce = 0;
 	again:
-		if (writev(f->f_file, iov, 6) == -1) {
+		if (writev(f->f_file, iov, IOVCNT) == -1) {
 			int e = errno;
 
 			/* allow to recover from file system full */
@@ -2201,7 +2200,7 @@ wallmsg(struct filed *f, struct iovec *iov)
 		strncpy(utline, ut.ut_line, sizeof(utline) - 1);
 		utline[sizeof(utline) - 1] = '\0';
 		if (f->f_type == F_WALL) {
-			ttymsg(iov, 6, utline);
+			ttymsg(utline, iov);
 			continue;
 		}
 		/* should we send the message to this user? */
@@ -2210,7 +2209,7 @@ wallmsg(struct filed *f, struct iovec *iov)
 				break;
 			if (!strncmp(f->f_un.f_uname[i], ut.ut_name,
 			    UT_NAMESIZE)) {
-				ttymsg(iov, 6, utline);
+				ttymsg(utline, iov);
 				break;
 			}
 		}
diff --git a/usr.sbin/syslogd/syslogd.h b/usr.sbin/syslogd/syslogd.h
index ff3efcf5985..55c53ea313f 100644
--- a/usr.sbin/syslogd/syslogd.h
+++ b/usr.sbin/syslogd/syslogd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: syslogd.h,v 1.33 2019/07/05 13:23:27 bluhm Exp $ */
+/*	$OpenBSD: syslogd.h,v 1.34 2021/09/03 16:28:33 bluhm Exp $ */
 
 /*
  * Copyright (c) 2014-2017 Alexander Bluhm <bluhm@genua.de>
@@ -35,10 +35,12 @@ int   priv_config_modified(void);
 int   priv_getaddrinfo(char *, char *, char *, struct sockaddr *, size_t);
 int   priv_getnameinfo(struct sockaddr *, socklen_t, char *, size_t);
 
+#define IOVCNT		6
+
 /* Terminal message */
 #define TTYMSGTIME	1		/* timeout used by ttymsg */
 #define TTYMAXDELAY	256		/* max events in ttymsg */
-void ttymsg(struct iovec *, int, char *);
+void ttymsg(char *, struct iovec *);
 
 /* File descriptor send/recv */
 void send_fd(int, int);
diff --git a/usr.sbin/syslogd/ttymsg.c b/usr.sbin/syslogd/ttymsg.c
index baa6e18ebfd..42fa1c1093c 100644
--- a/usr.sbin/syslogd/ttymsg.c
+++ b/usr.sbin/syslogd/ttymsg.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ttymsg.c,v 1.18 2019/06/28 13:32:51 deraadt Exp $	*/
+/*	$OpenBSD: ttymsg.c,v 1.19 2021/09/03 16:28:33 bluhm Exp $	*/
 /*	$NetBSD: ttymsg.c,v 1.3 1994/11/17 07:17:55 jtc Exp $	*/
 
 /*
@@ -62,10 +62,6 @@
 #include "log.h"
 #include "syslogd.h"
 
-#ifndef nitems
-#define nitems(_a) (sizeof((_a)) / sizeof((_a)[0]))
-#endif
-
 struct tty_delay {
 	struct event	 td_event;
 	size_t		 td_length;
@@ -80,18 +76,14 @@ void ttycb(int, short, void *);
  * seconds.
  */
 void
-ttymsg(struct iovec *iov, int iovcnt, char *utline)
+ttymsg(char *utline, struct iovec *iov)
 {
 	static char device[MAXNAMLEN] = _PATH_DEV;
+	struct iovec localiov[IOVCNT];
+	int iovcnt = IOVCNT;
 	int cnt, fd;
 	size_t left;
 	ssize_t wret;
-	struct iovec localiov[6];
-
-	if (iovcnt < 0 || (size_t)iovcnt > nitems(localiov)) {
-		log_warnx("too many iov's (change code in syslogd/ttymsg.c)");
-		return;
-	}
 
 	/*
 	 * Ignore lines that start with "ftp" or "uucp".
-- 
2.20.1