static int recv_headers( gnutls_session_t session, content_type_t type,
gnutls_handshake_description_t htype,
struct tls_record_st* record,
unsigned int *ms)
{
int ret;
gnutls_datum_t raw; /* raw headers */
/* Read the headers.
*/
record->header_size = record->packet_size = RECORD_HEADER_SIZE(session);
ret =
_gnutls_io_read_buffered (session, record->header_size, -1, ms);
if (ret != record->header_size)
{
if (ret < 0 && gnutls_error_is_fatal (ret) == 0)
return ret;
if (ret > 0)
ret = GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
else if (ret == 0)
ret = GNUTLS_E_PREMATURE_TERMINATION;
return gnutls_assert_val(ret);
}
ret = _mbuffer_linearize (&session->internals.record_recv_buffer);
if (ret < 0)
return gnutls_assert_val(ret);
_mbuffer_head_get_first (&session->internals.record_recv_buffer, &raw);
if (raw.size < RECORD_HEADER_SIZE(session))
return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
record_read_headers (session, raw.data, type, htype, record);
/* Check if the DTLS epoch is valid */
if (IS_DTLS(session))
{
if (_gnutls_epoch_is_valid(session, record->epoch) == 0)
{
_gnutls_audit_log(session, "Discarded message[%u] with invalid epoch %u.\n",
(unsigned int)_gnutls_uint64touint32 (&record->sequence),
(unsigned int)record->sequence.i[0]*256+(unsigned int)record->sequence.i[1]);
gnutls_assert();
/* doesn't matter, just a fatal error */
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
}
/* Here we check if the Type of the received packet is
* ok.
*/
if ((ret = check_recv_type (session, record->type)) < 0)
return gnutls_assert_val(ret);
/* Here we check if the advertized version is the one we
* negotiated in the handshake.
*/
if ((ret = record_check_version (session, htype, record->version)) < 0)
return gnutls_assert_val(ret);
if (record->length > MAX_RECV_SIZE(session))
{
_gnutls_audit_log
(session, "Received packet with illegal length: %u\n", (unsigned int)record->length);
return gnutls_assert_val(GNUTLS_E_UNEXPECTED_PACKET_LENGTH);
}
_gnutls_record_log
("REC[%p]: Expected Packet %s(%d)\n", session,
_gnutls_packet2str (type), type);
_gnutls_record_log ("REC[%p]: Received Packet %s(%d) with length: %d\n",
session,
_gnutls_packet2str (record->type), record->type, record->length);
return 0;
}
/* This function behaves exactly like read(). The only difference is
* that it accepts the gnutls_session_t and the content_type_t of data to
* receive (if called by the user the Content is Userdata only)
* It is intended to receive data, under the current session.
*
* The gnutls_handshake_description_t was introduced to support SSL V2.0 client hellos.
*/
ssize_t
_gnutls_recv_int (gnutls_session_t session, content_type_t type,
gnutls_handshake_description_t htype,
opaque * data, size_t sizeofdata)
{
int decrypted_length;
opaque version[2];
content_type_t recv_type;
uint16_t length;
uint8_t *ciphertext;
int ret, ret2;
uint16_t header_size;
int empty_packet = 0;
gnutls_datum_t data_enc, tmp;
record_parameters_st *record_params;
record_state_st *record_state;
ret = _gnutls_epoch_get (session, EPOCH_READ_CURRENT, &record_params);
if (ret < 0)
{
gnutls_assert ();
return ret;
}
/* Safeguard against processing data with an incomplete cipher state. */
if (!record_params->initialized)
{
gnutls_assert ();
return GNUTLS_E_INVALID_REQUEST;
}
record_state = &record_params->read;
if (type != GNUTLS_ALERT && (sizeofdata == 0 || data == NULL))
{
return GNUTLS_E_INVALID_REQUEST;
}
begin:
if (empty_packet > MAX_EMPTY_PACKETS_SEQUENCE)
{
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)
{
gnutls_assert ();
return GNUTLS_E_INVALID_SESSION;
}
/* If we have enough data in the cache do not bother receiving
* a new packet. (in order to flush the cache)
*/
ret = check_buffers (session, type, data, sizeofdata);
if (ret != 0)
return ret;
/* default headers for TLS 1.0
*/
header_size = RECORD_HEADER_SIZE;
if ((ret =
_gnutls_io_read_buffered (session, header_size, -1)) != header_size)
{
if (ret < 0 && gnutls_error_is_fatal (ret) == 0)
return ret;
session_invalidate (session);
if (type == GNUTLS_ALERT)
{
gnutls_assert ();
return 0; /* we were expecting close notify */
}
session_unresumable (session);
gnutls_assert ();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
ret = _mbuffer_linearize (&session->internals.record_recv_buffer);
if (ret != 0)
{
gnutls_assert ();
return ret;
}
_mbuffer_get_first (&session->internals.record_recv_buffer, &data_enc);
if ((ret =
record_check_headers (session, data_enc.data, type, htype, &recv_type,
version, &length, &header_size)) < 0)
{
gnutls_assert ();
return ret;
}
/* Here we check if the Type of the received packet is
* ok.
*/
if ((ret = check_recv_type (recv_type)) < 0)
{
gnutls_assert ();
return ret;
}
/* Here we check if the advertized version is the one we
* negotiated in the handshake.
*/
if ((ret = record_check_version (session, htype, version)) < 0)
{
gnutls_assert ();
session_invalidate (session);
return ret;
}
_gnutls_record_log
("REC[%p]: Expected Packet[%d] %s(%d) with length: %d\n", session,
(int) _gnutls_uint64touint32 (&record_state->sequence_number),
_gnutls_packet2str (type), type, (int) sizeofdata);
_gnutls_record_log ("REC[%p]: Received Packet[%d] %s(%d) with length: %d\n",
session,
(int)
_gnutls_uint64touint32 (&record_state->sequence_number),
_gnutls_packet2str (recv_type), recv_type, length);
if (length > MAX_RECV_SIZE)
{
_gnutls_record_log
("REC[%p]: FATAL ERROR: Received packet with length: %d\n",
session, length);
session_unresumable (session);
session_invalidate (session);
gnutls_assert ();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
/* check if we have that data into buffer.
*/
if ((ret =
_gnutls_io_read_buffered (session, header_size + length,
recv_type)) != header_size + length)
{
if (ret < 0 && gnutls_error_is_fatal (ret) == 0)
return ret;
session_unresumable (session);
session_invalidate (session);
gnutls_assert ();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
/* ok now we are sure that we can read all the data - so
* move on !
*/
ret = _mbuffer_linearize (&session->internals.record_recv_buffer);
if (ret != 0)
{
gnutls_assert ();
return ret;
}
_mbuffer_get_first (&session->internals.record_recv_buffer, &data_enc);
ciphertext = &data_enc.data[header_size];
ret = get_temp_recv_buffer (session, &tmp);
if (ret < 0)
{
gnutls_assert ();
return ret;
}
/* decrypt the data we got.
*/
ret =
_gnutls_decrypt (session, ciphertext, length, tmp.data, tmp.size,
recv_type, record_params);
if (ret < 0)
{
session_unresumable (session);
session_invalidate (session);
gnutls_assert ();
return ret;
}
_mbuffer_remove_bytes (&session->internals.record_recv_buffer,
header_size + length);
decrypted_length = ret;
/* Check if this is a CHANGE_CIPHER_SPEC
*/
if (type == GNUTLS_CHANGE_CIPHER_SPEC &&
recv_type == GNUTLS_CHANGE_CIPHER_SPEC)
{
_gnutls_record_log
("REC[%p]: ChangeCipherSpec Packet was received\n", session);
if ((size_t) ret != sizeofdata)
{ /* sizeofdata should be 1 */
gnutls_assert ();
return GNUTLS_E_UNEXPECTED_PACKET_LENGTH;
}
memcpy (data, tmp.data, sizeofdata);
return ret;
}
_gnutls_record_log
("REC[%p]: Decrypted Packet[%d] %s(%d) with length: %d\n", session,
(int) _gnutls_uint64touint32 (&record_state->sequence_number),
_gnutls_packet2str (recv_type), recv_type, decrypted_length);
/* increase sequence number
*/
if (_gnutls_uint64pp (&record_state->sequence_number) != 0)
{
session_invalidate (session);
gnutls_assert ();
return GNUTLS_E_RECORD_LIMIT_REACHED;
}
ret =
record_check_type (session, recv_type, type, htype, tmp.data,
decrypted_length);
if (ret < 0)
{
if (ret == GNUTLS_E_INT_RET_0)
return 0;
gnutls_assert ();
return ret;
}
/* Get Application data from buffer
*/
if ((recv_type == type) &&
(type == GNUTLS_APPLICATION_DATA ||
type == GNUTLS_HANDSHAKE || type == GNUTLS_INNER_APPLICATION))
{
ret = _gnutls_record_buffer_get (type, session, data, sizeofdata);
if (ret < 0)
{
gnutls_assert ();
return ret;
}
/* if the buffer just got empty
*/
if (_gnutls_record_buffer_get_size (type, session) == 0)
{
if ((ret2 = _gnutls_io_clear_peeked_data (session)) < 0)
{
gnutls_assert ();
return ret2;
}
}
}
else
{
gnutls_assert ();
return GNUTLS_E_UNEXPECTED_PACKET;
/* we didn't get what we wanted to
*/
}
/* (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 (ret == 0)
{
empty_packet++;
goto begin;
}
return ret;
}