1 files changed, 2 insertions, 0 deletions
diff --git a/zaptel.c b/zaptel.c
index d4a3098..db098f6 100755
--- a/zaptel.c
+++ b/zaptel.c
@@ -1472,6 +1472,8 @@ static ssize_t zt_chan_write(struct file *file, const char *usrbuf, size_t count
 	int res, amnt, oldbuf, rv,x;
 	if (!chan) 
 		return -EINVAL;
+	if (count < 1)
+		return -EINVAL;
 	for(;;) {
 		spin_lock_irqsave(&chan->lock, flags);
 		if (chan->curtone && !(chan->flags & ZT_FLAG_PSEUDO)) {