Fix packet length check in sptps_receive_data_datagram().

diff --git a/src/sptps.c b/src/sptps.c
index 99a3cea9fca47049bd070f6f3e0c0cc1f0452174..49e0a336de6a66436fb245507bb16d0ea869ac94 100644 (file)
--- a/src/sptps.c
+++ b/src/sptps.c
@@ -371,12 +371,12 @@ static bool receive_handshake(sptps_t *s, const char *data, uint16_t len) {
 
 // Check datagram for valid HMAC
 bool sptps_verify_datagram(sptps_t *s, const void *data, size_t len) {
-       if(len < 21)
-               return error(s, EIO, "Received short packet in sptps_verify_datagram");
-
        if (!s->instate)
                return error(s, EIO, "SPTPS state not ready to verify this datagram");
 
+       if(len < 21)
+               return error(s, EIO, "Received short packet in sptps_verify_datagram");
+
        uint32_t seqno;
        memcpy(&seqno, data, 4);
        seqno = ntohl(seqno);
@@ -391,12 +391,9 @@ bool sptps_verify_datagram(sptps_t *s, const void *data, size_t len) {
 static bool sptps_receive_data_datagram(sptps_t *s, const void *vdata, size_t len) {
        const char *data = vdata;
 
-       if(len < 21)
+       if(len < (s->instate ? 21 : 5))
                return error(s, EIO, "Received short packet in sptps_receive_data_datagram");
 
-       if (!s->instate)
-               return error(s, EIO, "SPTPS state not ready to verify this datagram");
-
        uint32_t seqno;
        memcpy(&seqno, data, 4);
        seqno = ntohl(seqno);