diff --git a/src/cwc.c b/src/cwc.c
index 6b38f212..431596a4 100644
--- a/src/cwc.c
+++ b/src/cwc.c
@@ -469,7 +469,7 @@ cwc_send_msg(cwc_t *cwc, const uint8_t *msg, size_t len, int sid, int enq)
   buf[4] = sid >> 8;
   buf[5] = sid;
 
-  if((len = des_encrypt(buf, len, cwc)) < 0) {
+  if((len = des_encrypt(buf, len, cwc)) <= 0) {
     free(buf);
     free(cm);
     return -1;
diff --git a/src/rawtsinput.c b/src/rawtsinput.c
index b1db456f..24a71d34 100644
--- a/src/rawtsinput.c
+++ b/src/rawtsinput.c
@@ -184,7 +184,7 @@ got_pat(const uint8_t *ptr, size_t len, void *opaque)
   len -= 8;
   ptr += 8;
 
-  if(len < 0)
+  if(len <= 0)
     return;
 
   pthread_mutex_lock(&global_lock);