/* addrinfo_wrap is used to build our own addrinfo "chain".
* (it has only one entry, so calling it a chain may be a stretch)
* It should ONLY be called when getaddrinfo() and friends
* aren't available, OR when dealing with a non IP protocol
* family, such as AF_UNIX
*
* the return value is 1 on success, or 0 on failure, which
* only happens if a memory allocation error occurred.
*/
static int addrinfo_wrap(int family, int socktype,
const void *where, size_t wherelen,
unsigned short port,
BIO_ADDRINFO **bai)
{
OPENSSL_assert(bai != NULL);
*bai = OPENSSL_zalloc(sizeof(**bai));
if (*bai == NULL)
return 0;
(*bai)->bai_family = family;
(*bai)->bai_socktype = socktype;
if (socktype == SOCK_STREAM)
(*bai)->bai_protocol = IPPROTO_TCP;
if (socktype == SOCK_DGRAM)
(*bai)->bai_protocol = IPPROTO_UDP;
#ifdef AF_UNIX
if (family == AF_UNIX)
(*bai)->bai_protocol = 0;
#endif
{
/* Magic: We know that BIO_ADDR_sockaddr_noconst is really
just an advanced cast of BIO_ADDR* to struct sockaddr *
by the power of union, so while it may seem that we're
creating a memory leak here, we are not. It will be
all right. */
BIO_ADDR *addr = BIO_ADDR_new();
if (addr != NULL) {
BIO_ADDR_rawmake(addr, family, where, wherelen, port);
(*bai)->bai_addr = BIO_ADDR_sockaddr_noconst(addr);
}
}
(*bai)->bai_next = NULL;
if ((*bai)->bai_addr == NULL) {
BIO_ADDRINFO_free(*bai);
*bai = NULL;
return 0;
}
return 1;
}
int BIO_accept(int sock, char **ip_port)
{
BIO_ADDR *res = BIO_ADDR_new();
int ret = -1;
if (res == NULL) {
BIOerr(BIO_F_BIO_ACCEPT, ERR_R_MALLOC_FAILURE);
return ret;
}
ret = BIO_accept_ex(sock, res, 0);
if (ret == (int)INVALID_SOCKET) {
if (BIO_sock_should_retry(ret)) {
ret = -2;
goto end;
}
SYSerr(SYS_F_ACCEPT, get_last_socket_error());
BIOerr(BIO_F_BIO_ACCEPT, BIO_R_ACCEPT_ERROR);
goto end;
}
if (ip_port != NULL) {
char *host = BIO_ADDR_hostname_string(res, 1);
char *port = BIO_ADDR_service_string(res, 1);
*ip_port = OPENSSL_zalloc(strlen(host) + strlen(port) + 2);
strcpy(*ip_port, host);
strcat(*ip_port, ":");
strcat(*ip_port, port);
OPENSSL_free(host);
OPENSSL_free(port);
}
end:
BIO_ADDR_free(res);
return ret;
}
int DTLSv1_listen(SSL *s, BIO_ADDR *client)
{
int next, n, ret = 0, clearpkt = 0;
unsigned char cookie[DTLS1_COOKIE_LENGTH];
unsigned char seq[SEQ_NUM_SIZE];
const unsigned char *data;
unsigned char *p, *buf;
unsigned long reclen, fragoff, fraglen, msglen;
unsigned int rectype, versmajor, msgseq, msgtype, clientvers, cookielen;
BIO *rbio, *wbio;
BUF_MEM *bufm;
BIO_ADDR *tmpclient = NULL;
PACKET pkt, msgpkt, msgpayload, session, cookiepkt;
/* Ensure there is no state left over from a previous invocation */
if (!SSL_clear(s))
return -1;
ERR_clear_error();
rbio = SSL_get_rbio(s);
wbio = SSL_get_wbio(s);
if (!rbio || !wbio) {
SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_BIO_NOT_SET);
return -1;
}
/*
* We only peek at incoming ClientHello's until we're sure we are going to
* to respond with a HelloVerifyRequest. If its a ClientHello with a valid
* cookie then we leave it in the BIO for accept to handle.
*/
BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL);
/*
* Note: This check deliberately excludes DTLS1_BAD_VER because that version
* requires the MAC to be calculated *including* the first ClientHello
* (without the cookie). Since DTLSv1_listen is stateless that cannot be
* supported. DTLS1_BAD_VER must use cookies in a stateful manner (e.g. via
* SSL_accept)
*/
if ((s->version & 0xff00) != (DTLS1_VERSION & 0xff00)) {
SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNSUPPORTED_SSL_VERSION);
return -1;
}
if (s->init_buf == NULL) {
if ((bufm = BUF_MEM_new()) == NULL) {
SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE);
return -1;
}
if (!BUF_MEM_grow(bufm, SSL3_RT_MAX_PLAIN_LENGTH)) {
BUF_MEM_free(bufm);
SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE);
return -1;
}
s->init_buf = bufm;
}
buf = (unsigned char *)s->init_buf->data;
do {
/* Get a packet */
clear_sys_error();
/*
* Technically a ClientHello could be SSL3_RT_MAX_PLAIN_LENGTH
* + DTLS1_RT_HEADER_LENGTH bytes long. Normally init_buf does not store
* the record header as well, but we do here. We've set up init_buf to
* be the standard size for simplicity. In practice we shouldn't ever
* receive a ClientHello as long as this. If we do it will get dropped
* in the record length check below.
*/
n = BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
if (n <= 0) {
if (BIO_should_retry(rbio)) {
/* Non-blocking IO */
goto end;
}
return -1;
}
/* If we hit any problems we need to clear this packet from the BIO */
clearpkt = 1;
if (!PACKET_buf_init(&pkt, buf, n)) {
SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_INTERNAL_ERROR);
return -1;
}
/*
* Parse the received record. If there are any problems with it we just
* dump it - with no alert. RFC6347 says this "Unlike TLS, DTLS is
* resilient in the face of invalid records (e.g., invalid formatting,
* length, MAC, etc.). In general, invalid records SHOULD be silently
* discarded, thus preserving the association; however, an error MAY be
* logged for diagnostic purposes."
*/
/* this packet contained a partial record, dump it */
if (n < DTLS1_RT_HEADER_LENGTH) {
SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_RECORD_TOO_SMALL);
goto end;
}
if (s->msg_callback)
s->msg_callback(0, 0, SSL3_RT_HEADER, buf,
DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
/* Get the record header */
if (!PACKET_get_1(&pkt, &rectype)
|| !PACKET_get_1(&pkt, &versmajor)) {
SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
goto end;
}
if (rectype != SSL3_RT_HANDSHAKE) {
SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
goto end;
}
/*
* Check record version number. We only check that the major version is
* the same.
*/
if (versmajor != DTLS1_VERSION_MAJOR) {
SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_BAD_PROTOCOL_VERSION_NUMBER);
goto end;
}
if (!PACKET_forward(&pkt, 1)
/* Save the sequence number: 64 bits, with top 2 bytes = epoch */
|| !PACKET_copy_bytes(&pkt, seq, SEQ_NUM_SIZE)
|| !PACKET_get_length_prefixed_2(&pkt, &msgpkt)) {
SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
goto end;
}
/*
* We allow data remaining at the end of the packet because there could
* be a second record (but we ignore it)
*/
/* This is an initial ClientHello so the epoch has to be 0 */
if (seq[0] != 0 || seq[1] != 0) {
SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
goto end;
}
/* Get a pointer to the raw message for the later callback */
data = PACKET_data(&msgpkt);
/* Finished processing the record header, now process the message */
if (!PACKET_get_1(&msgpkt, &msgtype)
|| !PACKET_get_net_3(&msgpkt, &msglen)
|| !PACKET_get_net_2(&msgpkt, &msgseq)
|| !PACKET_get_net_3(&msgpkt, &fragoff)
|| !PACKET_get_net_3(&msgpkt, &fraglen)
|| !PACKET_get_sub_packet(&msgpkt, &msgpayload, fraglen)
|| PACKET_remaining(&msgpkt) != 0) {
SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
goto end;
}
if (msgtype != SSL3_MT_CLIENT_HELLO) {
SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_UNEXPECTED_MESSAGE);
goto end;
}
/* Message sequence number can only be 0 or 1 */
if (msgseq > 2) {
SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_INVALID_SEQUENCE_NUMBER);
goto end;
}
/*
* We don't support fragment reassembly for ClientHellos whilst
* listening because that would require server side state (which is
* against the whole point of the ClientHello/HelloVerifyRequest
* mechanism). Instead we only look at the first ClientHello fragment
* and require that the cookie must be contained within it.
*/
if (fragoff != 0 || fraglen > msglen) {
/* Non initial ClientHello fragment (or bad fragment) */
SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_FRAGMENTED_CLIENT_HELLO);
goto end;
}
if (s->msg_callback)
s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, data,
fraglen + DTLS1_HM_HEADER_LENGTH, s,
s->msg_callback_arg);
if (!PACKET_get_net_2(&msgpayload, &clientvers)) {
SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
goto end;
}
/*
* Verify client version is supported
*/
if (DTLS_VERSION_LT(clientvers, (unsigned int)s->method->version) &&
s->method->version != DTLS_ANY_VERSION) {
SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_WRONG_VERSION_NUMBER);
goto end;
}
if (!PACKET_forward(&msgpayload, SSL3_RANDOM_SIZE)
|| !PACKET_get_length_prefixed_1(&msgpayload, &session)
|| !PACKET_get_length_prefixed_1(&msgpayload, &cookiepkt)) {
/*
* Could be malformed or the cookie does not fit within the initial
* ClientHello fragment. Either way we can't handle it.
*/
SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_LENGTH_MISMATCH);
goto end;
}
/*
* Check if we have a cookie or not. If not we need to send a
* HelloVerifyRequest.
*/
if (PACKET_remaining(&cookiepkt) == 0) {
next = LISTEN_SEND_VERIFY_REQUEST;
} else {
/*
* We have a cookie, so lets check it.
*/
if (s->ctx->app_verify_cookie_cb == NULL) {
SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_NO_VERIFY_COOKIE_CALLBACK);
/* This is fatal */
return -1;
}
if (s->ctx->app_verify_cookie_cb(s, PACKET_data(&cookiepkt),
PACKET_remaining(&cookiepkt)) ==
0) {
/*
* We treat invalid cookies in the same was as no cookie as
* per RFC6347
*/
next = LISTEN_SEND_VERIFY_REQUEST;
} else {
/* Cookie verification succeeded */
next = LISTEN_SUCCESS;
}
}
if (next == LISTEN_SEND_VERIFY_REQUEST) {
/*
* There was no cookie in the ClientHello so we need to send a
* HelloVerifyRequest. If this fails we do not worry about trying
* to resend, we just drop it.
*/
/*
* Dump the read packet, we don't need it any more. Ignore return
* value
*/
BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 0, NULL);
BIO_read(rbio, buf, SSL3_RT_MAX_PLAIN_LENGTH);
BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_PEEK_MODE, 1, NULL);
/* Generate the cookie */
if (s->ctx->app_gen_cookie_cb == NULL ||
s->ctx->app_gen_cookie_cb(s, cookie, &cookielen) == 0 ||
cookielen > 255) {
SSLerr(SSL_F_DTLSV1_LISTEN, SSL_R_COOKIE_GEN_CALLBACK_FAILURE);
/* This is fatal */
return -1;
}
p = &buf[DTLS1_RT_HEADER_LENGTH];
msglen = dtls_raw_hello_verify_request(p + DTLS1_HM_HEADER_LENGTH,
cookie, cookielen);
*p++ = DTLS1_MT_HELLO_VERIFY_REQUEST;
/* Message length */
l2n3(msglen, p);
/* Message sequence number is always 0 for a HelloVerifyRequest */
s2n(0, p);
/*
* We never fragment a HelloVerifyRequest, so fragment offset is 0
* and fragment length is message length
*/
l2n3(0, p);
l2n3(msglen, p);
/* Set reclen equal to length of whole handshake message */
reclen = msglen + DTLS1_HM_HEADER_LENGTH;
/* Add the record header */
p = buf;
*(p++) = SSL3_RT_HANDSHAKE;
/*
* Special case: for hello verify request, client version 1.0 and we
* haven't decided which version to use yet send back using version
* 1.0 header: otherwise some clients will ignore it.
*/
if (s->method->version == DTLS_ANY_VERSION) {
*(p++) = DTLS1_VERSION >> 8;
*(p++) = DTLS1_VERSION & 0xff;
} else {
*(p++) = s->version >> 8;
*(p++) = s->version & 0xff;
}
/*
* Record sequence number is always the same as in the received
* ClientHello
*/
memcpy(p, seq, SEQ_NUM_SIZE);
p += SEQ_NUM_SIZE;
/* Length */
s2n(reclen, p);
/*
* Set reclen equal to length of whole record including record
* header
*/
reclen += DTLS1_RT_HEADER_LENGTH;
if (s->msg_callback)
s->msg_callback(1, 0, SSL3_RT_HEADER, buf,
DTLS1_RT_HEADER_LENGTH, s, s->msg_callback_arg);
if ((tmpclient = BIO_ADDR_new()) == NULL) {
SSLerr(SSL_F_DTLSV1_LISTEN, ERR_R_MALLOC_FAILURE);
goto end;
}
/*
* This is unnecessary if rbio and wbio are one and the same - but
* maybe they're not. We ignore errors here - some BIOs do not
* support this.
*/
if (BIO_dgram_get_peer(rbio, tmpclient) > 0) {
(void)BIO_dgram_set_peer(wbio, tmpclient);
}
BIO_ADDR_free(tmpclient);
tmpclient = NULL;
if (BIO_write(wbio, buf, reclen) < (int)reclen) {
if (BIO_should_retry(wbio)) {
/*
* Non-blocking IO...but we're stateless, so we're just
* going to drop this packet.
*/
goto end;
}
return -1;
}
if (BIO_flush(wbio) <= 0) {
if (BIO_should_retry(wbio)) {
/*
* Non-blocking IO...but we're stateless, so we're just
* going to drop this packet.
*/
goto end;
}
return -1;
}
}
int main(void)
{
SSL_CTX *ctx = NULL;
SSL *ssl = NULL;
BIO *outbio = NULL;
BIO *inbio = NULL;
BIO_ADDR *peer = BIO_ADDR_new();
char *data;
long datalen;
int ret, success = 0;
size_t i;
ctx = SSL_CTX_new(DTLS_server_method());
if (ctx == NULL || peer == NULL)
goto err;
SSL_CTX_set_cookie_generate_cb(ctx, cookie_gen);
SSL_CTX_set_cookie_verify_cb(ctx, cookie_verify);
/* Create an SSL object for the connection */
ssl = SSL_new(ctx);
if (ssl == NULL)
goto err;
outbio = BIO_new(BIO_s_mem());
if (outbio == NULL)
goto err;
SSL_set_wbio(ssl, outbio);
success = 1;
for (i = 0; i < OSSL_NELEM(testpackets) && success; i++) {
inbio = BIO_new_mem_buf((char *)testpackets[i].in,
testpackets[i].inlen);
if (inbio == NULL) {
success = 0;
goto err;
}
/* Set Non-blocking IO behaviour */
BIO_set_mem_eof_return(inbio, -1);
SSL_set_rbio(ssl, inbio);
/* Process the incoming packet */
ret = DTLSv1_listen(ssl, peer);
if (ret < 0) {
success = 0;
goto err;
}
datalen = BIO_get_mem_data(outbio, &data);
if (testpackets[i].outtype == VERIFY) {
if (ret == 0) {
if (datalen != sizeof(verify)
|| (memcmp(data, verify, sizeof(verify)) != 0)) {
printf("Test %ld failure: incorrect HelloVerifyRequest\n", i);
success = 0;
} else {
printf("Test %ld success\n", i);
}
} else {
printf ("Test %ld failure: should not have succeeded\n", i);
success = 0;
}
} else if (datalen == 0) {
if ((ret == 0 && testpackets[i].outtype == DROP)
|| (ret == 1 && testpackets[i].outtype == GOOD)) {
printf("Test %ld success\n", i);
} else {
printf("Test %ld failure: wrong return value\n", i);
success = 0;
}
} else {
printf("Test %ld failure: Unexpected data output\n", i);
success = 0;
}
(void)BIO_reset(outbio);
inbio = NULL;
/* Frees up inbio */
SSL_set_rbio(ssl, NULL);
}
err:
if (!success)
ERR_print_errors_fp(stderr);
/* Also frees up outbio */
SSL_free(ssl);
SSL_CTX_free(ctx);
BIO_free(inbio);
OPENSSL_free(peer);
#ifndef OPENSSL_NO_CRYPTO_MDEBUG
CRYPTO_mem_leaks_fp(stderr);
#endif
return success ? 0 : 1;
}
