platform: add and use nm_utils_ifname_cpy() helper

Coverity complains rightly about "strncpy (dst, ifname, IFNAMSIZ)"
because it might leave @dst non-NULL-terminated, in case @ifname
is too long (which already would be a bug in the first place).

Replace the strcpy() uses by a new helper nm_utils_ifname_cpy()
that asserts against valid arguments.

7 files changed, 36 insertions, 20 deletions

diff --git a/src/devices/tests/test-lldp.c b/src/devices/tests/test-lldp.c
index dfae58b114..978821a686 100644
--- a/src/devices/tests/test-lldp.c
+++ b/src/devices/tests/test-lldp.c
@@ -27,8 +27,11 @@
 #include <sys/types.h>
 
 #include "nm-lldp-listener.h"
+
 #include "test-common.h"
 
+#include "nm-test-utils.h"
+
 typedef struct {
 	int ifindex;
 	int fd;
@@ -48,7 +51,7 @@ fixture_setup (test_fixture *fixture, gconstpointer user_data)
 	g_assert (fd >= 0);
 
 	ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
-	strncpy (ifr.ifr_name, TEST_IFNAME, IFNAMSIZ);
+	nm_utils_ifname_cpy (ifr.ifr_name, TEST_IFNAME);
 	g_assert (ioctl (fd, TUNSETIFF, &ifr) >= 0);
 
 	/* Bring the interface up */
diff --git a/src/nm-core-utils.c b/src/nm-core-utils.c
index 256be10888..8d0131a780 100644
--- a/src/nm-core-utils.c
+++ b/src/nm-core-utils.c
@@ -2942,4 +2942,15 @@ nm_utils_parse_debug_string (const char *string,
 	return result;
 }
 
+void
+nm_utils_ifname_cpy (char *dst, const char *name)
+{
+	g_return_if_fail (dst);
+	g_return_if_fail (name && name[0]);
+
+	nm_assert (nm_utils_iface_valid_name (name));
+
+	if (g_strlcpy (dst, name, IFNAMSIZ) >= IFNAMSIZ)
+		g_return_if_reached ();
+}
 
diff --git a/src/nm-core-utils.h b/src/nm-core-utils.h
index 7a69fb1928..91a0899690 100644
--- a/src/nm-core-utils.h
+++ b/src/nm-core-utils.h
@@ -412,4 +412,6 @@ guint nm_utils_parse_debug_string (const char *string,
                                    const GDebugKey *keys,
                                    guint nkeys);
 
+void nm_utils_ifname_cpy (char *dst, const char *name);
+
 #endif /* __NM_CORE_UTILS_H__ */
diff --git a/src/platform/nm-linux-platform.c b/src/platform/nm-linux-platform.c
index 5a34827622..eb90211fe4 100644
--- a/src/platform/nm-linux-platform.c
+++ b/src/platform/nm-linux-platform.c
@@ -4835,7 +4835,7 @@ tun_add (NMPlatform *platform, const char *name, gboolean tap,
 	if (fd < 0)
 		return FALSE;
 
-	strncpy (ifr.ifr_name, name, IFNAMSIZ);
+	nm_utils_ifname_cpy (ifr.ifr_name, name);
 	ifr.ifr_flags = tap ? IFF_TAP : IFF_TUN;
 
 	if (!pi)
diff --git a/src/platform/nm-platform-utils.c b/src/platform/nm-platform-utils.c
index 0f2656f238..6020a8f3be 100644
--- a/src/platform/nm-platform-utils.c
+++ b/src/platform/nm-platform-utils.c
@@ -56,7 +56,7 @@ ethtool_get (const char *name, gpointer edata)
 	nm_assert (strlen (name) < IFNAMSIZ);
 
 	memset (&ifr, 0, sizeof (ifr));
-	strcpy (ifr.ifr_name, name);
+	nm_utils_ifname_cpy (ifr.ifr_name, name);
 	ifr.ifr_data = edata;
 
 	fd = socket (PF_INET, SOCK_DGRAM, 0);
@@ -344,7 +344,7 @@ nmp_utils_mii_supports_carrier_detect (const char *ifname)
 	}
 
 	memset (&ifr, 0, sizeof (struct ifreq));
-	strncpy (ifr.ifr_name, ifname, IFNAMSIZ);
+	nm_utils_ifname_cpy (ifr.ifr_name, ifname);
 
 	errno = 0;
 	if (ioctl (fd, SIOCGMIIPHY, &ifr) < 0) {
@@ -513,13 +513,14 @@ gboolean
 nmp_utils_device_exists (const char *name)
 {
 #define SYS_CLASS_NET "/sys/class/net/"
-	char sysdir[NM_STRLEN (SYS_CLASS_NET) + IFNAMSIZ] = SYS_CLASS_NET;
+	char sysdir[NM_STRLEN (SYS_CLASS_NET) + IFNAMSIZ];
 
 	if (   !name
 	    || strlen (name) >= IFNAMSIZ
 	    || !nm_utils_is_valid_path_component (name))
 		g_return_val_if_reached (FALSE);
 
-	strcpy (&sysdir[NM_STRLEN (SYS_CLASS_NET)], name);
+	memcpy (sysdir, SYS_CLASS_NET, NM_STRLEN (SYS_CLASS_NET));
+	nm_utils_ifname_cpy (&sysdir[NM_STRLEN (SYS_CLASS_NET)], name);
 	return g_file_test (sysdir, G_FILE_TEST_EXISTS);
 }
diff --git a/src/platform/tests/test-general.c b/src/platform/tests/test-general.c
index f342e5653e..eb5adb9541 100644
--- a/src/platform/tests/test-general.c
+++ b/src/platform/tests/test-general.c
@@ -18,12 +18,11 @@
  * Copyright (C) 2015 Red Hat, Inc.
  */
 
-#include "nm-platform-utils.h"
+#include "nm-default.h"
 
 #include <linux/rtnetlink.h>
 
 #include "nm-linux-platform.h"
-#include "nm-default.h"
 
 #include "nm-test-utils.h"
 
diff --git a/src/platform/wifi/wifi-utils-wext.c b/src/platform/wifi/wifi-utils-wext.c
index 613c03b7b2..26f4ce41a8 100644
--- a/src/platform/wifi/wifi-utils-wext.c
+++ b/src/platform/wifi/wifi-utils-wext.c
@@ -101,7 +101,7 @@ wifi_wext_get_mode (WifiData *data)
 	struct iwreq wrq;
 
 	memset (&wrq, 0, sizeof (struct iwreq));
-	g_strlcpy (wrq.ifr_name, wext->parent.iface, IFNAMSIZ);
+	nm_utils_ifname_cpy (wrq.ifr_name, wext->parent.iface);
 
 	if (ioctl (wext->fd, SIOCGIWMODE, &wrq) < 0) {
 		if (errno != ENODEV) {
@@ -150,7 +150,7 @@ wifi_wext_set_mode (WifiData *data, const NM80211Mode mode)
 		return FALSE;
 	}
 
-	g_strlcpy (wrq.ifr_name, wext->parent.iface, IFNAMSIZ);
+	nm_utils_ifname_cpy (wrq.ifr_name, wext->parent.iface);
 	if (ioctl (wext->fd, SIOCSIWMODE, &wrq) < 0) {
 		if (errno != ENODEV) {
 			nm_log_err (LOGD_HW | LOGD_WIFI, "(%s): error setting mode %d",
@@ -174,7 +174,7 @@ wifi_wext_set_powersave (WifiData *data, guint32 powersave)
 	} else
 		wrq.u.power.disabled = 1;
 
-	g_strlcpy (wrq.ifr_name, wext->parent.iface, IFNAMSIZ);
+	nm_utils_ifname_cpy (wrq.ifr_name, wext->parent.iface);
 	if (ioctl (wext->fd, SIOCSIWPOWER, &wrq) < 0) {
 		if (errno != ENODEV) {
 			nm_log_err (LOGD_HW | LOGD_WIFI, "(%s): error setting powersave %" G_GUINT32_FORMAT,
@@ -193,7 +193,7 @@ wifi_wext_get_freq (WifiData *data)
 	struct iwreq wrq;
 
 	memset (&wrq, 0, sizeof (struct iwreq));
-	g_strlcpy (wrq.ifr_name, wext->parent.iface, IFNAMSIZ);
+	nm_utils_ifname_cpy (wrq.ifr_name, wext->parent.iface);
 	if (ioctl (wext->fd, SIOCGIWFREQ, &wrq) < 0) {
 		nm_log_warn (LOGD_HW | LOGD_WIFI,
 		             "(%s): error getting frequency: %s",
@@ -227,7 +227,7 @@ wifi_wext_get_bssid (WifiData *data, guint8 *out_bssid)
 	struct iwreq wrq;
 
 	memset (&wrq, 0, sizeof (wrq));
-	g_strlcpy (wrq.ifr_name, wext->parent.iface, IFNAMSIZ);
+	nm_utils_ifname_cpy (wrq.ifr_name, wext->parent.iface);
 	if (ioctl (wext->fd, SIOCGIWAP, &wrq) < 0) {
 		nm_log_warn (LOGD_HW | LOGD_WIFI,
 		             "(%s): error getting associated BSSID: %s",
@@ -246,7 +246,7 @@ wifi_wext_get_rate (WifiData *data)
 	int err;
 
 	memset (&wrq, 0, sizeof (wrq));
-	g_strlcpy (wrq.ifr_name, wext->parent.iface, IFNAMSIZ);
+	nm_utils_ifname_cpy (wrq.ifr_name, wext->parent.iface);
 	err = ioctl (wext->fd, SIOCGIWRATE, &wrq);
 	return ((err == 0) ? wrq.u.bitrate.value / 1000 : 0);
 }
@@ -356,7 +356,7 @@ wifi_wext_get_qual (WifiData *data)
 	wrq.u.data.pointer = &stats;
 	wrq.u.data.length = sizeof (stats);
 	wrq.u.data.flags = 1;  /* Clear updated flag */
-	g_strlcpy (wrq.ifr_name, wext->parent.iface, IFNAMSIZ);
+	nm_utils_ifname_cpy (wrq.ifr_name, wext->parent.iface);
 
 	if (ioctl (wext->fd, SIOCGIWSTATS, &wrq) < 0) {
 		nm_log_warn (LOGD_HW | LOGD_WIFI,
@@ -393,7 +393,7 @@ wifi_wext_set_mesh_channel (WifiData *data, guint32 channel)
 	struct iwreq wrq;
 
 	memset (&wrq, 0, sizeof (struct iwreq));
-	g_strlcpy (wrq.ifr_name, wext->parent.iface, IFNAMSIZ);
+	nm_utils_ifname_cpy (wrq.ifr_name, wext->parent.iface);
 
 	if (channel > 0) {
 		wrq.u.freq.flags = IW_FREQ_FIXED;
@@ -425,7 +425,7 @@ wifi_wext_set_mesh_ssid (WifiData *data, const guint8 *ssid, gsize len)
 	wrq.u.essid.length = len;
 	wrq.u.essid.flags = (len > 0) ? 1 : 0; /* 1=enable SSID, 0=disable/any */
 
-	g_strlcpy (wrq.ifr_name, wext->parent.iface, IFNAMSIZ);
+	nm_utils_ifname_cpy (wrq.ifr_name, wext->parent.iface);
 	if (ioctl (wext->fd, SIOCSIWESSID, &wrq) == 0)
 		return TRUE;
 
@@ -448,7 +448,7 @@ wext_can_scan (WifiDataWext *wext)
 	struct iwreq wrq;
 
 	memset (&wrq, 0, sizeof (struct iwreq));
-	g_strlcpy (wrq.ifr_name, wext->parent.iface, IFNAMSIZ);
+	nm_utils_ifname_cpy (wrq.ifr_name, wext->parent.iface);
 	if (ioctl (wext->fd, SIOCSIWSCAN, &wrq) < 0) {
 		if (errno == EOPNOTSUPP)
 			return FALSE;
@@ -466,7 +466,7 @@ wext_get_range (WifiDataWext *wext,
 	struct iwreq wrq;
 
 	memset (&wrq, 0, sizeof (struct iwreq));
-	g_strlcpy (wrq.ifr_name, wext->parent.iface, IFNAMSIZ);
+	nm_utils_ifname_cpy (wrq.ifr_name, wext->parent.iface);
 	wrq.u.data.pointer = (caddr_t) range;
 	wrq.u.data.length = sizeof (struct iw_range);
 
@@ -666,7 +666,7 @@ wifi_wext_is_wifi (const char *iface)
 
 	fd = socket (PF_INET, SOCK_DGRAM, 0);
 	if (fd >= 0) {
-		g_strlcpy (iwr.ifr_ifrn.ifrn_name, iface, IFNAMSIZ);
+		nm_utils_ifname_cpy (iwr.ifr_ifrn.ifrn_name, iface);
 		if (ioctl (fd, SIOCGIWNAME, &iwr) == 0)
 			is_wifi = TRUE;
 		close (fd);