lightningd: don't allow zero cltv HTLCs. (#2214)

rustyrussell · cdecker · commit 3006844f926c · 2019-01-04T01:08:35.000+01:00
Fixes: #2077 Fixes: #2213 Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/lightningd/peer_htlcs.c b/lightningd/peer_htlcs.c
@@ -199,7 +199,7 @@ static bool check_amount(struct htlc_in *hin,
 static bool check_cltv(struct htlc_in *hin,
 		       u32 cltv_expiry, u32 outgoing_cltv_value, u32 delta)
 {
-	if (cltv_expiry - delta >= outgoing_cltv_value)
+	if (delta < cltv_expiry && cltv_expiry - delta >= outgoing_cltv_value)
 		return true;
 	log_debug(hin->key.channel->log, "HTLC %"PRIu64" incorrect CLTV:"
 		  " %u in, %u out, delta reqd %u",

Original file line number	Diff line number	Diff line change
`@@ -199,7 +199,7 @@ static bool check_amount(struct htlc_in *hin,`
`199`	`199`	`static bool check_cltv(struct htlc_in *hin,`
`200`	`200`	`u32 cltv_expiry, u32 outgoing_cltv_value, u32 delta)`
`201`	`201`	`{`
`202`		`- if (cltv_expiry - delta >= outgoing_cltv_value)`
	`202`	`+ if (delta < cltv_expiry && cltv_expiry - delta >= outgoing_cltv_value)`
`203`	`203`	`return true;`
`204`	`204`	`log_debug(hin->key.channel->log, "HTLC %"PRIu64" incorrect CLTV:"`
`205`	`205`	`" %u in, %u out, delta reqd %u",`