From: Guus Sliepen <guus@meshlink.io>
Date: Fri, 8 Aug 2014 09:52:13 +0000 (+0200)
Subject: Actually implement sptps_verify_datagram(), so try_mac() works.
X-Git-Url: http://git.meshlink.io/?p=meshlink;a=commitdiff_plain;h=693fbd414983fdc87a34786093e0dbfab4542f6a

Actually implement sptps_verify_datagram(), so try_mac() works.
---

diff --git a/src/sptps.c b/src/sptps.c
index e03b18a8..917b1e20 100644
--- a/src/sptps.c
+++ b/src/sptps.c
@@ -374,9 +374,14 @@ bool sptps_verify_datagram(sptps_t *s, const void *data, size_t len) {
 	if(!s->instate || len < 21)
 		return error(s, EIO, "Received short packet");
 
-	// TODO: just decrypt without updating the replay window
+	uint32_t seqno;
+	memcpy(&seqno, data, 4);
+	seqno = ntohl(seqno);
+	// TODO: check whether seqno makes sense, to avoid CPU intensive decrypt
 
-	return true;
+	char buffer[len];
+	size_t outlen;
+	return chacha_poly1305_decrypt(s->incipher, seqno, data + 4, len - 4, buffer, &outlen);
 }
 
 // Receive incoming data, datagram version.