libnm: reject colon in nm_utils_is_valid_iface_name()

Since kernel commit a4176a9391868bfa87705bcd2e3b49e9b9dd2996 (net:
reject creation of netdev names with colons), kernel rejects any
colons in the interface name.

Since kernel could get away with tightening up the check, we can
too.

The user anyway can not choose arbitrary interface names, like
"all", "default", "bonding_masters" are all going to fail one
way or another.

1 files changed, 19 insertions, 13 deletions

diff --git a/libnm-core/nm-utils.c b/libnm-core/nm-utils.c
index 7e96184340..e700b714e7 100644
--- a/libnm-core/nm-utils.c
+++ b/libnm-core/nm-utils.c
@@ -32,6 +32,7 @@
 #include <libintl.h>
 #include <gmodule.h>
 #include <sys/stat.h>
+#include <net/if.h>
 
 #if WITH_JANSSON
 #include <jansson.h>
@@ -3675,36 +3676,41 @@ _nm_utils_generate_mac_address_mask_parse (const char *value,
 gboolean
 nm_utils_is_valid_iface_name (const char *name, GError **error)
 {
-	g_return_val_if_fail (name != NULL, FALSE);
+	int i;
 
-	if (*name == '\0') {
-		g_set_error_literal (error, NM_UTILS_ERROR, NM_UTILS_ERROR_UNKNOWN,
-		                     _("interface name is too short"));
-		return FALSE;
-	}
+	g_return_val_if_fail (name, FALSE);
 
-	if (strlen (name) >= 16) {
+	if (name[0] == '\0') {
 		g_set_error_literal (error, NM_UTILS_ERROR, NM_UTILS_ERROR_UNKNOWN,
-		                     _("interface name is longer than 15 characters"));
+		                     _("interface name is too short"));
 		return FALSE;
 	}
 
-	if (!strcmp (name, ".") || !strcmp (name, "..")) {
+	if (   name[0] == '.'
+	    && (   name[1] == '\0'
+	        || (   name[1] == '.'
+	            && name[2] == '\0'))) {
 		g_set_error_literal (error, NM_UTILS_ERROR, NM_UTILS_ERROR_UNKNOWN,
 		                     _("interface name is reserved"));
 		return FALSE;
 	}
 
-	while (*name) {
-		if (*name == '/' || g_ascii_isspace (*name)) {
+	for (i = 0; i < IFNAMSIZ; i++) {
+		char ch = name[i];
+
+		if (ch == '\0')
+			return TRUE;
+		if (   NM_IN_SET (ch, '/', ':')
+		    || g_ascii_isspace (ch)) {
 			g_set_error_literal (error, NM_UTILS_ERROR, NM_UTILS_ERROR_UNKNOWN,
 			                     _("interface name contains an invalid character"));
 			return FALSE;
 		}
-		name++;
 	}
 
-	return TRUE;
+	g_set_error_literal (error, NM_UTILS_ERROR, NM_UTILS_ERROR_UNKNOWN,
+	                     _("interface name is longer than 15 characters"));
+	return FALSE;
 }
 
 /**