From: Mike Frysinger <vapier@gentoo.org>
Date: Thu, 29 Dec 2016 23:12:33 +0000 (-0500)
Subject: vunshare: check socket() return
X-Git-Url: https://git.wh0rd.org/?p=home.git;a=commitdiff_plain;h=2b4610c75ec8fbb0ea9b77107dd77869833ef0fe

vunshare: check socket() return
---

diff --git a/vunshare.c b/vunshare.c
index 274eebc..2e7efbb 100644
--- a/vunshare.c
+++ b/vunshare.c
@@ -51,14 +51,19 @@ static void unshare_net(void)
 	if (!vunshare(CLONE_NEWNET))
 		return;
 
-	int sock = socket(AF_LOCAL, SOCK_DGRAM|SOCK_CLOEXEC, 0);
+	int sock;
 	struct ifreq ifr;
 
+	sock = socket(AF_LOCAL, SOCK_DGRAM|SOCK_CLOEXEC, 0);
+	if (sock < 0)
+		err(1, "socket(AF_LOCAL) failed");
+
 	/* Equiv of `ip link set up lo`.  Kernel will assign 127.0.0.1 for us. */
 	strcpy(ifr.ifr_name, "lo");
 	if (ioctl(sock, SIOCGIFFLAGS, &ifr) < 0)
 		err(1, "ioctl(SIOCGIFFLAGS) failed");
-	strcpy(ifr.ifr_name, "lo");
+
+	/* The kernel preserves ifr.ifr_name for use. */
 	ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
 	if (ioctl(sock, SIOCSIFFLAGS, &ifr) < 0)
 		err(1, "ioctl(SIOCSIFFLAGS) failed");