From 72c5b7d85d06d6f71960ff00e780b87ca9d33d78 Mon Sep 17 00:00:00 2001
From: Damien Miller <djm@mindrot.org>
Date: Fri, 6 Jan 2006 14:50:44 +1100
Subject: =?UTF-8?q?=20=20=20-=20djm@cvs.openbsd.org=202006/01/05=2023:43:5?=
 =?UTF-8?q?3=20=20=20=20=20=20[misc.c]=20=20=20=20=20=20check=20that=20std?=
 =?UTF-8?q?io=20file=20descriptors=20are=20actually=20closed=20before=20cl?=
 =?UTF-8?q?obbering=20=20=20=20=20=20them=20in=20sanitise=5Fstdfd().=20pro?=
 =?UTF-8?q?blems=20occurred=20when=20a=20lower=20numbered=20fd=20was=20=20?=
 =?UTF-8?q?=20=20=20=20closed,=20but=20higher=20ones=20weren't.=20spotted?=
 =?UTF-8?q?=20by,=20and=20patch=20tested=20by=20=20=20=20=20=20Fr=C3=A9d?=
 =?UTF-8?q?=C3=A9ric=20Olivi=C3=A9?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 misc.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

(limited to 'misc.c')

diff --git a/misc.c b/misc.c
index 0339cede..b876c003 100644
--- a/misc.c
+++ b/misc.c
@@ -24,7 +24,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: misc.c,v 1.40 2006/01/02 07:53:44 reyk Exp $");
+RCSID("$OpenBSD: misc.c,v 1.41 2006/01/05 23:43:53 djm Exp $");
 
 #ifdef SSH_TUN_OPENBSD
 #include <net/if.h>
@@ -616,18 +616,20 @@ tun_open(int tun, int mode)
 void
 sanitise_stdfd(void)
 {
-	int nullfd;
+	int nullfd, dupfd;
 
-	if ((nullfd = open(_PATH_DEVNULL, O_RDWR)) == -1) {
+	if ((nullfd = dupfd = open(_PATH_DEVNULL, O_RDWR)) == -1) {
 		fprintf(stderr, "Couldn't open /dev/null: %s", strerror(errno));
 		exit(1);
 	}
-	while (nullfd < 2) {
-		if (dup2(nullfd, nullfd + 1) == -1) {
+	while (++dupfd <= 2) {
+		/* Only clobber closed fds */
+		if (fcntl(dupfd, F_GETFL, 0) >= 0)
+			continue;
+		if (dup2(nullfd, dupfd) == -1) {
 			fprintf(stderr, "dup2: %s", strerror(errno));
 			exit(1);
 		}
-		nullfd++;
 	}
 	if (nullfd > 2)
 		close(nullfd);
-- 
cgit v1.2.3