diff --git a/external/ppp/pppd/eap.c b/external/ppp/pppd/eap.c
index 6203f94d0a..48547e6be3 100644
--- a/external/ppp/pppd/eap.c
+++ b/external/ppp/pppd/eap.c
@@ -1421,7 +1421,7 @@ int len;
 		}
 
 		/* Not so likely to happen. */
-		if (vallen >= len + sizeof (rhostname)) {
+		if (len - vallen >= sizeof (rhostname)) {
 			dbglog("EAP: trimming really long peer name down");
 			BCOPY(inp + vallen, rhostname, sizeof (rhostname) - 1);
 			rhostname[sizeof (rhostname) - 1] = '\0';
@@ -1847,7 +1847,7 @@ int len;
 		}
 
 		/* Not so likely to happen. */
-		if (vallen >= len + sizeof (rhostname)) {
+		if (len - vallen >= sizeof (rhostname)) {
 			dbglog("EAP: trimming really long peer name down");
 			BCOPY(inp + vallen, rhostname, sizeof (rhostname) - 1);
 			rhostname[sizeof (rhostname) - 1] = '\0';