diff options
Diffstat (limited to 'src/udp-serv.c')
| -rw-r--r-- | src/udp-serv.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/src/udp-serv.c b/src/udp-serv.c index fdaa0fb886..2d82482876 100644 --- a/src/udp-serv.c +++ b/src/udp-serv.c @@ -56,6 +56,15 @@ static ssize_t pull_func(gnutls_transport_ptr_t p, void *data, #define MAX_BUFFER 255 /* Longest string to echo */ +/* record layer indication for a handshake packet */ +#define HANDSHAKE_CONTENT_TYPE 22 +/* TLS record content is the first by of the packet */ +#define RECORD_CONTENT_POS 0 +/* handshake type is first byte in Handshake packet; + * we have to skip type;version;epoch;sequence_number; + * and length in DTLSPlaintext */ +#define HANDSHAKE_TYPE_POS 13 + void udp_server(const char *name, int port, int mtu) { int sock, ret; @@ -91,7 +100,11 @@ void udp_server(const char *name, int port, int mtu) recvfrom(sock, buffer, sizeof(buffer)-1, MSG_PEEK, (struct sockaddr *) &cli_addr, &cli_addr_size); - if (ret > 0) { + + /* only accept a valid client hello */ + if (ret > HANDSHAKE_TYPE_POS && + buffer[RECORD_CONTENT_POS] == HANDSHAKE_CONTENT_TYPE && + buffer[HANDSHAKE_TYPE_POS] == GNUTLS_HANDSHAKE_CLIENT_HELLO) { if (!HAVE_OPT(NOCOOKIE)) { memset(&prestate, 0, sizeof(prestate)); ret = @@ -222,8 +235,8 @@ void udp_server(const char *name, int port, int mtu) } } } + gnutls_deinit(session); } - gnutls_deinit(session); } /* Wait for data to be received within a timeout period in milliseconds |