From: Hans Dedecker <dedeckeh@gmail.com>
Date: Thu, 3 May 2018 15:21:15 +0000 (+0200)
Subject: odhcpd: fix strncpy bounds
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=4983ee551a743e55bb2f2ec12ceab0ddba13eb2d;p=project%2Fodhcpd.git

odhcpd: fix strncpy bounds

Fix strncpy bounds as reported by Coverity in CID 1412278 and 1412293

Signed-off-by: Hans Dedecker <dedeckeh@gmail.com>
---

diff --git a/src/dhcpv4.c b/src/dhcpv4.c
index db5f138..35a3ad0 100644
--- a/src/dhcpv4.c
+++ b/src/dhcpv4.c
@@ -779,8 +779,10 @@ static void handle_dhcpv4(void *addr, void *data, size_t len,
 		}
 	}
 
-	struct ifreq ifr = {.ifr_name = ""};
-	strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name));
+	struct ifreq ifr;
+
+	memset(&ifr, 0, sizeof(ifr));
+	strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name) - 1);
 
 	if (!ioctl(sock, SIOCGIFMTU, &ifr)) {
 		uint16_t mtu = htons(ifr.ifr_mtu);
diff --git a/src/odhcpd.c b/src/odhcpd.c
index 71b803d..8aa4571 100644
--- a/src/odhcpd.c
+++ b/src/odhcpd.c
@@ -143,10 +143,12 @@ int odhcpd_get_interface_config(const char *ifname, const char *what)
 int odhcpd_get_mac(const struct interface *iface, uint8_t mac[6])
 {
 	struct ifreq ifr;
+
 	memset(&ifr, 0, sizeof(ifr));
-	strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name));
+	strncpy(ifr.ifr_name, iface->ifname, sizeof(ifr.ifr_name) - 1);
 	if (ioctl(ioctl_sock, SIOCGIFHWADDR, &ifr) < 0)
 		return -1;
+
 	memcpy(mac, ifr.ifr_hwaddr.sa_data, 6);
 	return 0;
 }