int
_gnutls_record_buffer_get_packet(content_type_t type, gnutls_session_t session, gnutls_packet_t *packet)
{
mbuffer_st *bufel;
bufel =
_mbuffer_head_pop_first(&session->internals.record_buffer);
if (bufel == NULL)
return
gnutls_assert_val
(GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE);
if (type != bufel->type) {
if (IS_DTLS(session))
_gnutls_audit_log(session,
"Discarded unexpected %s (%d) packet (expecting: %s)\n",
_gnutls_packet2str(bufel->type),
(int) bufel->type,
_gnutls_packet2str(type));
_mbuffer_head_remove_bytes(&session->internals.
record_buffer, bufel->msg.size);
return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET);
}
*packet = bufel;
return bufel->msg.size - bufel->mark;
}
/* This is a receive function for the gnutls handshake
* protocol. Makes sure that we have received all data.
*
* htype is the next handshake packet expected.
*/
int _gnutls_parse_record_buffered_msgs(gnutls_session_t session)
{
gnutls_datum_t msg;
mbuffer_st *bufel = NULL, *prev = NULL;
int ret;
size_t data_size;
handshake_buffer_st *recv_buf =
session->internals.handshake_recv_buffer;
bufel =
_mbuffer_head_get_first(&session->internals.record_buffer,
&msg);
if (bufel == NULL)
return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
if (!IS_DTLS(session)) {
ssize_t append, header_size;
do {
if (bufel->type != GNUTLS_HANDSHAKE)
return
gnutls_assert_val
(GNUTLS_E_UNEXPECTED_PACKET);
if (unlikely
(session->internals.handshake_recv_buffer_size == 0 &&
msg.size < HANDSHAKE_HEADER_SIZE(session) &&
session->internals.handshake_header_recv_buffer.byte_length <
HANDSHAKE_HEADER_SIZE(session) - msg.size)) {
bufel = _mbuffer_head_pop_first(&session->internals.record_buffer);
_mbuffer_enqueue(&session->internals.handshake_header_recv_buffer,
bufel);
break;
} else if (session->internals.handshake_recv_buffer_size >
0 && recv_buf[0].length > recv_buf[0].data.length) {
/* this is the rest of a previous message */
append = MIN(msg.size,
recv_buf[0].length -
recv_buf[0].data.length);
ret =
_gnutls_buffer_append_data(&recv_buf
[0].data,
msg.data,
append);
if (ret < 0)
return gnutls_assert_val(ret);
_mbuffer_head_remove_bytes(&session->
internals.
record_buffer,
append);
} else { /* received new message */
if (unlikely
(session->internals.
handshake_header_recv_buffer.length > 0)) {
bufel = _mbuffer_head_pop_first(&session->internals.
record_buffer);
_mbuffer_enqueue(&session->internals.
handshake_header_recv_buffer,
bufel);
ret = _mbuffer_linearize_align16(&session->internals.
handshake_header_recv_buffer,
get_total_headers(session));
if (ret < 0)
return gnutls_assert_val(ret);
bufel = _mbuffer_head_pop_first(&session->internals.
handshake_header_recv_buffer);
_mbuffer_head_push_first(&session->internals.
record_buffer,
bufel);
}
ret =
parse_handshake_header(session, bufel,
&recv_buf[0]);
if (ret < 0)
return gnutls_assert_val(ret);
header_size = ret;
session->internals.
handshake_recv_buffer_size = 1;
_mbuffer_set_uhead_size(bufel,
header_size);
data_size =
MIN(recv_buf[0].length,
_mbuffer_get_udata_size(bufel));
ret =
_gnutls_buffer_append_data(&recv_buf
[0].data,
_mbuffer_get_udata_ptr
(bufel),
data_size);
if (ret < 0)
return gnutls_assert_val(ret);
_mbuffer_set_uhead_size(bufel, 0);
_mbuffer_head_remove_bytes(&session->
internals.
record_buffer,
data_size +
header_size);
}
/* if packet is complete then return it
*/
if (recv_buf[0].length == recv_buf[0].data.length) {
return 0;
}
bufel =
_mbuffer_head_get_first(&session->internals.
record_buffer, &msg);
}
while (bufel != NULL);
/* if we are here it means that the received packets were not
* enough to complete the handshake packet.
*/
return gnutls_assert_val(GNUTLS_E_AGAIN);
} else { /* DTLS */
handshake_buffer_st tmp;
do {
/* we now
* 0. parse headers
* 1. insert to handshake_recv_buffer
* 2. sort handshake_recv_buffer on sequence numbers
* 3. return first packet if completed or GNUTLS_E_AGAIN.
*/
do {
if (bufel->type != GNUTLS_HANDSHAKE) {
gnutls_assert();
goto next; /* ignore packet */
}
_gnutls_handshake_buffer_init(&tmp);
ret =
parse_handshake_header(session, bufel,
&tmp);
if (ret < 0) {
gnutls_assert();
_gnutls_audit_log(session,
"Invalid handshake packet headers. Discarding.\n");
break;
}
_mbuffer_consume(&session->internals.
record_buffer, bufel,
ret);
data_size =
MIN(tmp.length,
tmp.end_offset - tmp.start_offset +
1);
ret =
_gnutls_buffer_append_data(&tmp.data,
_mbuffer_get_udata_ptr
(bufel),
data_size);
if (ret < 0)
return gnutls_assert_val(ret);
_mbuffer_consume(&session->internals.
record_buffer, bufel,
data_size);
ret =
merge_handshake_packet(session, &tmp);
if (ret < 0)
return gnutls_assert_val(ret);
}
while (_mbuffer_get_udata_size(bufel) > 0);
prev = bufel;
bufel =
_mbuffer_dequeue(&session->internals.
record_buffer, bufel);
_mbuffer_xfree(&prev);
continue;
next:
bufel = _mbuffer_head_get_next(bufel, NULL);
}
while (bufel != NULL);
/* sort in descending order */
if (session->internals.handshake_recv_buffer_size > 1)
qsort(recv_buf,
session->internals.
handshake_recv_buffer_size,
sizeof(recv_buf[0]), handshake_compare);
while (session->internals.handshake_recv_buffer_size > 0 &&
recv_buf[LAST_ELEMENT].sequence <
session->internals.dtls.hsk_read_seq) {
_gnutls_audit_log(session,
"Discarded replayed handshake packet with sequence %d\n",
recv_buf[LAST_ELEMENT].sequence);
_gnutls_handshake_buffer_clear(&recv_buf
[LAST_ELEMENT]);
session->internals.handshake_recv_buffer_size--;
}
return 0;
}
}
/* @ms: is the number of milliseconds to wait for data. Use zero for indefinite.
*
* This will receive record layer packets and add them to
* application_data_buffer and handshake_data_buffer.
*
* If the htype is not -1 then handshake timeouts
* will be enforced.
*/
ssize_t
_gnutls_recv_in_buffers (gnutls_session_t session, content_type_t type,
gnutls_handshake_description_t htype, unsigned int ms)
{
uint64 *packet_sequence;
gnutls_datum_t ciphertext;
mbuffer_st* bufel = NULL, *decrypted = NULL;
gnutls_datum_t t;
int ret;
unsigned int empty_fragments = 0;
record_parameters_st *record_params;
record_state_st *record_state;
struct tls_record_st record;
begin:
if (empty_fragments > session->internals.priorities.max_empty_records)
{
gnutls_assert ();
return GNUTLS_E_TOO_MANY_EMPTY_PACKETS;
}
if (session->internals.read_eof != 0)
{
/* if we have already read an EOF
*/
return 0;
}
else if (session_is_valid (session) != 0
|| session->internals.may_not_read != 0)
return gnutls_assert_val(GNUTLS_E_INVALID_SESSION);
/* get the record state parameters */
ret = _gnutls_epoch_get (session, EPOCH_READ_CURRENT, &record_params);
if (ret < 0)
return gnutls_assert_val (ret);
/* Safeguard against processing data with an incomplete cipher state. */
if (!record_params->initialized)
return gnutls_assert_val (GNUTLS_E_INTERNAL_ERROR);
record_state = &record_params->read;
/* receive headers */
ret = recv_headers(session, type, htype, &record, &ms);
if (ret < 0)
{
ret = gnutls_assert_val_fatal(ret);
goto recv_error;
}
if (IS_DTLS(session))
packet_sequence = &record.sequence;
else
packet_sequence = &record_state->sequence_number;
/* Read the packet data and insert it to record_recv_buffer.
*/
ret =
_gnutls_io_read_buffered (session, record.packet_size,
record.type, &ms);
if (ret != record.packet_size)
{
gnutls_assert();
goto recv_error;
}
/* ok now we are sure that we have read all the data - so
* move on !
*/
ret = _mbuffer_linearize (&session->internals.record_recv_buffer);
if (ret < 0)
return gnutls_assert_val(ret);
bufel = _mbuffer_head_get_first (&session->internals.record_recv_buffer, NULL);
if (bufel == NULL)
return gnutls_assert_val(GNUTLS_E_INTERNAL_ERROR);
/* We allocate the maximum possible to allow few compressed bytes to expand to a
* full record.
*/
decrypted = _mbuffer_alloc(record.length, record.length);
if (decrypted == NULL)
return gnutls_assert_val(GNUTLS_E_MEMORY_ERROR);
ciphertext.data = (uint8_t*)_mbuffer_get_udata_ptr(bufel) + record.header_size;
ciphertext.size = record.length;
/* decrypt the data we got.
*/
t.data = _mbuffer_get_udata_ptr(decrypted);
t.size = _mbuffer_get_udata_size(decrypted);
ret =
_gnutls_decrypt (session, &ciphertext, &t,
record.type, record_params, packet_sequence);
if (ret >= 0) _mbuffer_set_udata_size(decrypted, ret);
_mbuffer_head_remove_bytes (&session->internals.record_recv_buffer,
record.header_size + record.length);
if (ret < 0)
{
gnutls_assert();
_gnutls_audit_log(session, "Discarded message[%u] due to invalid decryption\n",
(unsigned int)_gnutls_uint64touint32 (packet_sequence));
goto sanity_check_error;
}
/* check for duplicates. We check after the message
* is processed and authenticated to avoid someone
* messing with our windows.
*/
if (IS_DTLS(session) && session->internals.no_replay_protection == 0)
{
ret = _dtls_record_check(record_params, packet_sequence);
if (ret < 0)
{
_gnutls_audit_log(session, "Discarded duplicate message[%u.%u]: %s\n",
(unsigned int)record.sequence.i[0]*256 +(unsigned int)record.sequence.i[1],
(unsigned int) _gnutls_uint64touint32 (packet_sequence), _gnutls_packet2str (record.type));
goto sanity_check_error;
}
_gnutls_record_log
("REC[%p]: Decrypted Packet[%u.%u] %s(%d) with length: %d\n", session,
(unsigned int)record.sequence.i[0]*256 +(unsigned int)record.sequence.i[1],
(unsigned int) _gnutls_uint64touint32 (packet_sequence),
_gnutls_packet2str (record.type), record.type, (int)_mbuffer_get_udata_size(decrypted));
}
else
{
_gnutls_record_log
("REC[%p]: Decrypted Packet[%u] %s(%d) with length: %d\n", session,
(unsigned int) _gnutls_uint64touint32 (packet_sequence),
_gnutls_packet2str (record.type), record.type, (int)_mbuffer_get_udata_size(decrypted));
}
/* increase sequence number
*/
if (!IS_DTLS(session) && sequence_increment (session, &record_state->sequence_number) != 0)
{
session_invalidate (session);
gnutls_assert ();
ret = GNUTLS_E_RECORD_LIMIT_REACHED;
goto sanity_check_error;
}
/* (originally for) TLS 1.0 CBC protection.
* Actually this code is called if we just received
* an empty packet. An empty TLS packet is usually
* sent to protect some vulnerabilities in the CBC mode.
* In that case we go to the beginning and start reading
* the next packet.
*/
if (_mbuffer_get_udata_size(decrypted) == 0)
{
_mbuffer_xfree(&decrypted);
empty_fragments++;
goto begin;
}
if (record.v2)
decrypted->htype = GNUTLS_HANDSHAKE_CLIENT_HELLO_V2;
else
{
uint8_t * p = _mbuffer_get_udata_ptr(decrypted);
decrypted->htype = p[0];
}
ret =
record_add_to_buffers (session, &record, type, htype,
packet_sequence, decrypted);
/* bufel is now either deinitialized or buffered somewhere else */
if (ret < 0)
return gnutls_assert_val(ret);
return ret;
discard:
session->internals.dtls.packets_dropped++;
/* discard the whole received fragment. */
bufel = _mbuffer_head_pop_first(&session->internals.record_recv_buffer);
_mbuffer_xfree(&bufel);
return gnutls_assert_val(GNUTLS_E_AGAIN);
sanity_check_error:
if (IS_DTLS(session))
{
session->internals.dtls.packets_dropped++;
ret = gnutls_assert_val(GNUTLS_E_AGAIN);
goto cleanup;
}
session_unresumable (session);
session_invalidate (session);
cleanup:
_mbuffer_xfree(&decrypted);
return ret;
recv_error:
if (ret < 0 && (gnutls_error_is_fatal (ret) == 0 || ret == GNUTLS_E_TIMEDOUT))
return ret;
if (type == GNUTLS_ALERT) /* we were expecting close notify */
{
session_invalidate (session);
gnutls_assert ();
return 0;
}
if (IS_DTLS(session))
{
goto discard;
}
session_invalidate (session);
session_unresumable (session);
if (ret == 0)
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
else
return ret;
}
