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gecko-dev/security/nss/lib/ssl/dtlscon.c

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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/*
* DTLS Protocol
*/
#include "ssl.h"
#include "sslimpl.h"
#include "sslproto.h"
#ifndef PR_ARRAY_SIZE
#define PR_ARRAY_SIZE(a) (sizeof(a)/sizeof((a)[0]))
#endif
static SECStatus dtls_TransmitMessageFlight(sslSocket *ss);
static void dtls_RetransmitTimerExpiredCb(sslSocket *ss);
static SECStatus dtls_SendSavedWriteData(sslSocket *ss);
/* -28 adjusts for the IP/UDP header */
static const PRUint16 COMMON_MTU_VALUES[] = {
1500 - 28, /* Ethernet MTU */
1280 - 28, /* IPv6 minimum MTU */
576 - 28, /* Common assumption */
256 - 28 /* We're in serious trouble now */
};
#define DTLS_COOKIE_BYTES 32
/* List copied from ssl3con.c:cipherSuites */
static const ssl3CipherSuite nonDTLSSuites[] = {
#ifndef NSS_DISABLE_ECC
TLS_ECDHE_ECDSA_WITH_RC4_128_SHA,
TLS_ECDHE_RSA_WITH_RC4_128_SHA,
#endif /* NSS_DISABLE_ECC */
TLS_DHE_DSS_WITH_RC4_128_SHA,
#ifndef NSS_DISABLE_ECC
TLS_ECDH_RSA_WITH_RC4_128_SHA,
TLS_ECDH_ECDSA_WITH_RC4_128_SHA,
#endif /* NSS_DISABLE_ECC */
TLS_RSA_WITH_RC4_128_MD5,
TLS_RSA_WITH_RC4_128_SHA,
TLS_RSA_EXPORT1024_WITH_RC4_56_SHA,
TLS_RSA_EXPORT_WITH_RC4_40_MD5,
0 /* End of list marker */
};
/* Map back and forth between TLS and DTLS versions in wire format.
* Mapping table is:
*
* TLS DTLS
* 1.1 (0302) 1.0 (feff)
* 1.2 (0303) 1.2 (fefd)
* 1.3 (0304) 1.3 (fefc)
*/
SSL3ProtocolVersion
dtls_TLSVersionToDTLSVersion(SSL3ProtocolVersion tlsv)
{
if (tlsv == SSL_LIBRARY_VERSION_TLS_1_1) {
return SSL_LIBRARY_VERSION_DTLS_1_0_WIRE;
}
if (tlsv == SSL_LIBRARY_VERSION_TLS_1_2) {
return SSL_LIBRARY_VERSION_DTLS_1_2_WIRE;
}
if (tlsv == SSL_LIBRARY_VERSION_TLS_1_3) {
return SSL_LIBRARY_VERSION_DTLS_1_3_WIRE;
}
/* Anything other than TLS 1.1 or 1.2 is an error, so return
* the invalid version 0xffff. */
return 0xffff;
}
/* Map known DTLS versions to known TLS versions.
* - Invalid versions (< 1.0) return a version of 0
* - Versions > known return a version one higher than we know of
* to accomodate a theoretically newer version */
SSL3ProtocolVersion
dtls_DTLSVersionToTLSVersion(SSL3ProtocolVersion dtlsv)
{
if (MSB(dtlsv) == 0xff) {
return 0;
}
if (dtlsv == SSL_LIBRARY_VERSION_DTLS_1_0_WIRE) {
return SSL_LIBRARY_VERSION_TLS_1_1;
}
if (dtlsv == SSL_LIBRARY_VERSION_DTLS_1_2_WIRE) {
return SSL_LIBRARY_VERSION_TLS_1_2;
}
if (dtlsv == SSL_LIBRARY_VERSION_DTLS_1_3_WIRE) {
return SSL_LIBRARY_VERSION_TLS_1_3;
}
/* Return a fictional higher version than we know of */
return SSL_LIBRARY_VERSION_TLS_1_2 + 1;
}
/* On this socket, Disable non-DTLS cipher suites in the argument's list */
SECStatus
ssl3_DisableNonDTLSSuites(sslSocket * ss)
{
const ssl3CipherSuite * suite;
for (suite = nonDTLSSuites; *suite; ++suite) {
SECStatus rv = ssl3_CipherPrefSet(ss, *suite, PR_FALSE);
PORT_Assert(rv == SECSuccess); /* else is coding error */
}
return SECSuccess;
}
/* Allocate a DTLSQueuedMessage.
*
* Called from dtls_QueueMessage()
*/
static DTLSQueuedMessage *
dtls_AllocQueuedMessage(PRUint16 epoch, SSL3ContentType type,
const unsigned char *data, PRUint32 len)
{
DTLSQueuedMessage *msg = NULL;
msg = PORT_ZAlloc(sizeof(DTLSQueuedMessage));
if (!msg)
return NULL;
msg->data = PORT_Alloc(len);
if (!msg->data) {
PORT_Free(msg);
return NULL;
}
PORT_Memcpy(msg->data, data, len);
msg->len = len;
msg->epoch = epoch;
msg->type = type;
return msg;
}
/*
* Free a handshake message
*
* Called from dtls_FreeHandshakeMessages()
*/
static void
dtls_FreeHandshakeMessage(DTLSQueuedMessage *msg)
{
if (!msg)
return;
PORT_ZFree(msg->data, msg->len);
PORT_Free(msg);
}
/*
* Free a list of handshake messages
*
* Called from:
* dtls_HandleHandshake()
* ssl3_DestroySSL3Info()
*/
void
dtls_FreeHandshakeMessages(PRCList *list)
{
PRCList *cur_p;
while (!PR_CLIST_IS_EMPTY(list)) {
cur_p = PR_LIST_TAIL(list);
PR_REMOVE_LINK(cur_p);
dtls_FreeHandshakeMessage((DTLSQueuedMessage *)cur_p);
}
}
/* Called only from ssl3_HandleRecord, for each (deciphered) DTLS record.
* origBuf is the decrypted ssl record content and is expected to contain
* complete handshake records
* Caller must hold the handshake and RecvBuf locks.
*
* Note that this code uses msg_len for two purposes:
*
* (1) To pass the length to ssl3_HandleHandshakeMessage()
* (2) To carry the length of a message currently being reassembled
*
* However, unlike ssl3_HandleHandshake(), it is not used to carry
* the state of reassembly (i.e., whether one is in progress). That
* is carried in recvdHighWater and recvdFragments.
*/
#define OFFSET_BYTE(o) (o/8)
#define OFFSET_MASK(o) (1 << (o%8))
SECStatus
dtls_HandleHandshake(sslSocket *ss, sslBuffer *origBuf)
{
/* XXX OK for now.
* This doesn't work properly with asynchronous certificate validation.
* because that returns a WOULDBLOCK error. The current DTLS
* applications do not need asynchronous validation, but in the
* future we will need to add this.
*/
sslBuffer buf = *origBuf;
SECStatus rv = SECSuccess;
PORT_Assert(ss->opt.noLocks || ssl_HaveRecvBufLock(ss));
PORT_Assert(ss->opt.noLocks || ssl_HaveSSL3HandshakeLock(ss));
while (buf.len > 0) {
PRUint8 type;
PRUint32 message_length;
PRUint16 message_seq;
PRUint32 fragment_offset;
PRUint32 fragment_length;
PRUint32 offset;
if (buf.len < 12) {
PORT_SetError(SSL_ERROR_RX_MALFORMED_HANDSHAKE);
rv = SECFailure;
break;
}
/* Parse the header */
type = buf.buf[0];
message_length = (buf.buf[1] << 16) | (buf.buf[2] << 8) | buf.buf[3];
message_seq = (buf.buf[4] << 8) | buf.buf[5];
fragment_offset = (buf.buf[6] << 16) | (buf.buf[7] << 8) | buf.buf[8];
fragment_length = (buf.buf[9] << 16) | (buf.buf[10] << 8) | buf.buf[11];
#define MAX_HANDSHAKE_MSG_LEN 0x1ffff /* 128k - 1 */
if (message_length > MAX_HANDSHAKE_MSG_LEN) {
(void)ssl3_DecodeError(ss);
PORT_SetError(SSL_ERROR_RX_MALFORMED_HANDSHAKE);
return SECFailure;
}
#undef MAX_HANDSHAKE_MSG_LEN
buf.buf += 12;
buf.len -= 12;
/* This fragment must be complete */
if (buf.len < fragment_length) {
PORT_SetError(SSL_ERROR_RX_MALFORMED_HANDSHAKE);
rv = SECFailure;
break;
}
/* Sanity check the packet contents */
if ((fragment_length + fragment_offset) > message_length) {
PORT_SetError(SSL_ERROR_RX_MALFORMED_HANDSHAKE);
rv = SECFailure;
break;
}
/* There are three ways we could not be ready for this packet.
*
* 1. It's a partial next message.
* 2. It's a partial or complete message beyond the next
* 3. It's a message we've already seen
*
* If it's the complete next message we accept it right away.
* This is the common case for short messages
*/
if ((message_seq == ss->ssl3.hs.recvMessageSeq)
&& (fragment_offset == 0)
&& (fragment_length == message_length)) {
/* Complete next message. Process immediately */
ss->ssl3.hs.msg_type = (SSL3HandshakeType)type;
ss->ssl3.hs.msg_len = message_length;
/* At this point we are advancing our state machine, so
* we can free our last flight of messages */
dtls_FreeHandshakeMessages(&ss->ssl3.hs.lastMessageFlight);
ss->ssl3.hs.recvdHighWater = -1;
dtls_CancelTimer(ss);
/* Reset the timer to the initial value if the retry counter
* is 0, per Sec. 4.2.4.1 */
if (ss->ssl3.hs.rtRetries == 0) {
ss->ssl3.hs.rtTimeoutMs = INITIAL_DTLS_TIMEOUT_MS;
}
rv = ssl3_HandleHandshakeMessage(ss, buf.buf, ss->ssl3.hs.msg_len);
if (rv == SECFailure) {
/* Do not attempt to process rest of messages in this record */
break;
}
} else {
if (message_seq < ss->ssl3.hs.recvMessageSeq) {
/* Case 3: we do an immediate retransmit if we're
* in a waiting state*/
if (ss->ssl3.hs.rtTimerCb == NULL) {
/* Ignore */
} else if (ss->ssl3.hs.rtTimerCb ==
dtls_RetransmitTimerExpiredCb) {
SSL_TRC(30, ("%d: SSL3[%d]: Retransmit detected",
SSL_GETPID(), ss->fd));
/* Check to see if we retransmitted recently. If so,
* suppress the triggered retransmit. This avoids
* retransmit wars after packet loss.
* This is not in RFC 5346 but should be
*/
if ((PR_IntervalNow() - ss->ssl3.hs.rtTimerStarted) >
(ss->ssl3.hs.rtTimeoutMs / 4)) {
SSL_TRC(30,
("%d: SSL3[%d]: Shortcutting retransmit timer",
SSL_GETPID(), ss->fd));
/* Cancel the timer and call the CB,
* which re-arms the timer */
dtls_CancelTimer(ss);
dtls_RetransmitTimerExpiredCb(ss);
rv = SECSuccess;
break;
} else {
SSL_TRC(30,
("%d: SSL3[%d]: We just retransmitted. Ignoring.",
SSL_GETPID(), ss->fd));
rv = SECSuccess;
break;
}
} else if (ss->ssl3.hs.rtTimerCb == dtls_FinishedTimerCb) {
/* Retransmit the messages and re-arm the timer
* Note that we are not backing off the timer here.
* The spec isn't clear and my reasoning is that this
* may be a re-ordered packet rather than slowness,
* so let's be aggressive. */
dtls_CancelTimer(ss);
rv = dtls_TransmitMessageFlight(ss);
if (rv == SECSuccess) {
rv = dtls_StartTimer(ss, dtls_FinishedTimerCb);
}
if (rv != SECSuccess)
return rv;
break;
}
} else if (message_seq > ss->ssl3.hs.recvMessageSeq) {
/* Case 2
*
* Ignore this message. This means we don't handle out of
* order complete messages that well, but we're still
* compliant and this probably does not happen often
*
* XXX OK for now. Maybe do something smarter at some point?
*/
} else {
/* Case 1
*
* Buffer the fragment for reassembly
*/
/* Make room for the message */
if (ss->ssl3.hs.recvdHighWater == -1) {
PRUint32 map_length = OFFSET_BYTE(message_length) + 1;
rv = sslBuffer_Grow(&ss->ssl3.hs.msg_body, message_length);
if (rv != SECSuccess)
break;
/* Make room for the fragment map */
rv = sslBuffer_Grow(&ss->ssl3.hs.recvdFragments,
map_length);
if (rv != SECSuccess)
break;
/* Reset the reassembly map */
ss->ssl3.hs.recvdHighWater = 0;
PORT_Memset(ss->ssl3.hs.recvdFragments.buf, 0,
ss->ssl3.hs.recvdFragments.space);
ss->ssl3.hs.msg_type = (SSL3HandshakeType)type;
ss->ssl3.hs.msg_len = message_length;
}
/* If we have a message length mismatch, abandon the reassembly
* in progress and hope that the next retransmit will give us
* something sane
*/
if (message_length != ss->ssl3.hs.msg_len) {
ss->ssl3.hs.recvdHighWater = -1;
PORT_SetError(SSL_ERROR_RX_MALFORMED_HANDSHAKE);
rv = SECFailure;
break;
}
/* Now copy this fragment into the buffer */
PORT_Assert((fragment_offset + fragment_length) <=
ss->ssl3.hs.msg_body.space);
PORT_Memcpy(ss->ssl3.hs.msg_body.buf + fragment_offset,
buf.buf, fragment_length);
/* This logic is a bit tricky. We have two values for
* reassembly state:
*
* - recvdHighWater contains the highest contiguous number of
* bytes received
* - recvdFragments contains a bitmask of packets received
* above recvdHighWater
*
* This avoids having to fill in the bitmask in the common
* case of adjacent fragments received in sequence
*/
if (fragment_offset <= ss->ssl3.hs.recvdHighWater) {
/* Either this is the adjacent fragment or an overlapping
* fragment */
ss->ssl3.hs.recvdHighWater = fragment_offset +
fragment_length;
} else {
for (offset = fragment_offset;
offset < fragment_offset + fragment_length;
offset++) {
ss->ssl3.hs.recvdFragments.buf[OFFSET_BYTE(offset)] |=
OFFSET_MASK(offset);
}
}
/* Now figure out the new high water mark if appropriate */
for (offset = ss->ssl3.hs.recvdHighWater;
offset < ss->ssl3.hs.msg_len; offset++) {
/* Note that this loop is not efficient, since it counts
* bit by bit. If we have a lot of out-of-order packets,
* we should optimize this */
if (ss->ssl3.hs.recvdFragments.buf[OFFSET_BYTE(offset)] &
OFFSET_MASK(offset)) {
ss->ssl3.hs.recvdHighWater++;
} else {
break;
}
}
/* If we have all the bytes, then we are good to go */
if (ss->ssl3.hs.recvdHighWater == ss->ssl3.hs.msg_len) {
ss->ssl3.hs.recvdHighWater = -1;
rv = ssl3_HandleHandshakeMessage(ss,
ss->ssl3.hs.msg_body.buf,
ss->ssl3.hs.msg_len);
if (rv == SECFailure)
break; /* Skip rest of record */
/* At this point we are advancing our state machine, so
* we can free our last flight of messages */
dtls_FreeHandshakeMessages(&ss->ssl3.hs.lastMessageFlight);
dtls_CancelTimer(ss);
/* If there have been no retries this time, reset the
* timer value to the default per Section 4.2.4.1 */
if (ss->ssl3.hs.rtRetries == 0) {
ss->ssl3.hs.rtTimeoutMs = INITIAL_DTLS_TIMEOUT_MS;
}
}
}
}
buf.buf += fragment_length;
buf.len -= fragment_length;
}
origBuf->len = 0; /* So ssl3_GatherAppDataRecord will keep looping. */
/* XXX OK for now. In future handle rv == SECWouldBlock safely in order
* to deal with asynchronous certificate verification */
return rv;
}
/* Enqueue a message (either handshake or CCS)
*
* Called from:
* dtls_StageHandshakeMessage()
* ssl3_SendChangeCipherSpecs()
*/
SECStatus dtls_QueueMessage(sslSocket *ss, SSL3ContentType type,
const SSL3Opaque *pIn, PRInt32 nIn)
{
SECStatus rv = SECSuccess;
DTLSQueuedMessage *msg = NULL;
PORT_Assert(ss->opt.noLocks || ssl_HaveSSL3HandshakeLock(ss));
PORT_Assert(ss->opt.noLocks || ssl_HaveXmitBufLock(ss));
msg = dtls_AllocQueuedMessage(ss->ssl3.cwSpec->epoch, type, pIn, nIn);
if (!msg) {
PORT_SetError(SEC_ERROR_NO_MEMORY);
rv = SECFailure;
} else {
PR_APPEND_LINK(&msg->link, &ss->ssl3.hs.lastMessageFlight);
}
return rv;
}
/* Add DTLS handshake message to the pending queue
* Empty the sendBuf buffer.
* This function returns SECSuccess or SECFailure, never SECWouldBlock.
* Always set sendBuf.len to 0, even when returning SECFailure.
*
* Called from:
* ssl3_AppendHandshakeHeader()
* dtls_FlushHandshake()
*/
SECStatus
dtls_StageHandshakeMessage(sslSocket *ss)
{
SECStatus rv = SECSuccess;
PORT_Assert(ss->opt.noLocks || ssl_HaveSSL3HandshakeLock(ss));
PORT_Assert(ss->opt.noLocks || ssl_HaveXmitBufLock(ss));
/* This function is sometimes called when no data is actually to
* be staged, so just return SECSuccess. */
if (!ss->sec.ci.sendBuf.buf || !ss->sec.ci.sendBuf.len)
return rv;
rv = dtls_QueueMessage(ss, content_handshake,
ss->sec.ci.sendBuf.buf, ss->sec.ci.sendBuf.len);
/* Whether we succeeded or failed, toss the old handshake data. */
ss->sec.ci.sendBuf.len = 0;
return rv;
}
/* Enqueue the handshake message in sendBuf (if any) and then
* transmit the resulting flight of handshake messages.
*
* Called from:
* ssl3_FlushHandshake()
*/
SECStatus
dtls_FlushHandshakeMessages(sslSocket *ss, PRInt32 flags)
{
SECStatus rv = SECSuccess;
PORT_Assert(ss->opt.noLocks || ssl_HaveSSL3HandshakeLock(ss));
PORT_Assert(ss->opt.noLocks || ssl_HaveXmitBufLock(ss));
rv = dtls_StageHandshakeMessage(ss);
if (rv != SECSuccess)
return rv;
if (!(flags & ssl_SEND_FLAG_FORCE_INTO_BUFFER)) {
rv = dtls_TransmitMessageFlight(ss);
if (rv != SECSuccess)
return rv;
if (!(flags & ssl_SEND_FLAG_NO_RETRANSMIT)) {
ss->ssl3.hs.rtRetries = 0;
rv = dtls_StartTimer(ss, dtls_RetransmitTimerExpiredCb);
}
}
return rv;
}
/* The callback for when the retransmit timer expires
*
* Called from:
* dtls_CheckTimer()
* dtls_HandleHandshake()
*/
static void
dtls_RetransmitTimerExpiredCb(sslSocket *ss)
{
SECStatus rv = SECFailure;
ss->ssl3.hs.rtRetries++;
if (!(ss->ssl3.hs.rtRetries % 3)) {
/* If one of the messages was potentially greater than > MTU,
* then downgrade. Do this every time we have retransmitted a
* message twice, per RFC 6347 Sec. 4.1.1 */
dtls_SetMTU(ss, ss->ssl3.hs.maxMessageSent - 1);
}
rv = dtls_TransmitMessageFlight(ss);
if (rv == SECSuccess) {
/* Re-arm the timer */
rv = dtls_RestartTimer(ss, PR_TRUE, dtls_RetransmitTimerExpiredCb);
}
if (rv == SECFailure) {
/* XXX OK for now. In future maybe signal the stack that we couldn't
* transmit. For now, let the read handle any real network errors */
}
}
/* Transmit a flight of handshake messages, stuffing them
* into as few records as seems reasonable
*
* Called from:
* dtls_FlushHandshake()
* dtls_RetransmitTimerExpiredCb()
*/
static SECStatus
dtls_TransmitMessageFlight(sslSocket *ss)
{
SECStatus rv = SECSuccess;
PRCList *msg_p;
PRUint16 room_left = ss->ssl3.mtu;
PRInt32 sent;
ssl_GetXmitBufLock(ss);
ssl_GetSpecReadLock(ss);
/* DTLS does not buffer its handshake messages in
* ss->pendingBuf, but rather in the lastMessageFlight
* structure. This is just a sanity check that
* some programming error hasn't inadvertantly
* stuffed something in ss->pendingBuf
*/
PORT_Assert(!ss->pendingBuf.len);
for (msg_p = PR_LIST_HEAD(&ss->ssl3.hs.lastMessageFlight);
msg_p != &ss->ssl3.hs.lastMessageFlight;
msg_p = PR_NEXT_LINK(msg_p)) {
DTLSQueuedMessage *msg = (DTLSQueuedMessage *)msg_p;
/* The logic here is:
*
* 1. If this is a message that will not fit into the remaining
* space, then flush.
* 2. If the message will now fit into the remaining space,
* encrypt, buffer, and loop.
* 3. If the message will not fit, then fragment.
*
* At the end of the function, flush.
*/
if ((msg->len + SSL3_BUFFER_FUDGE) > room_left) {
/* The message will not fit into the remaining space, so flush */
rv = dtls_SendSavedWriteData(ss);
if (rv != SECSuccess)
break;
room_left = ss->ssl3.mtu;
}
if ((msg->len + SSL3_BUFFER_FUDGE) <= room_left) {
/* The message will fit, so encrypt and then continue with the
* next packet */
sent = ssl3_SendRecord(ss, msg->epoch, msg->type,
msg->data, msg->len,
ssl_SEND_FLAG_FORCE_INTO_BUFFER |
ssl_SEND_FLAG_USE_EPOCH);
if (sent != msg->len) {
rv = SECFailure;
if (sent != -1) {
PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
}
break;
}
room_left = ss->ssl3.mtu - ss->pendingBuf.len;
} else {
/* The message will not fit, so fragment.
*
* XXX OK for now. Arrange to coalesce the last fragment
* of this message with the next message if possible.
* That would be more efficient.
*/
PRUint32 fragment_offset = 0;
unsigned char fragment[DTLS_MAX_MTU]; /* >= than largest
* plausible MTU */
/* Assert that we have already flushed */
PORT_Assert(room_left == ss->ssl3.mtu);
/* Case 3: We now need to fragment this message
* DTLS only supports fragmenting handshaking messages */
PORT_Assert(msg->type == content_handshake);
/* The headers consume 12 bytes so the smalles possible
* message (i.e., an empty one) is 12 bytes
*/
PORT_Assert(msg->len >= 12);
while ((fragment_offset + 12) < msg->len) {
PRUint32 fragment_len;
const unsigned char *content = msg->data + 12;
PRUint32 content_len = msg->len - 12;
/* The reason we use 8 here is that that's the length of
* the new DTLS data that we add to the header */
fragment_len = PR_MIN(room_left - (SSL3_BUFFER_FUDGE + 8),
content_len - fragment_offset);
PORT_Assert(fragment_len < DTLS_MAX_MTU - 12);
/* Make totally sure that we are within the buffer.
* Note that the only way that fragment len could get
* adjusted here is if
*
* (a) we are in release mode so the PORT_Assert is compiled out
* (b) either the MTU table is inconsistent with DTLS_MAX_MTU
* or ss->ssl3.mtu has become corrupt.
*/
fragment_len = PR_MIN(fragment_len, DTLS_MAX_MTU - 12);
/* Construct an appropriate-sized fragment */
/* Type, length, sequence */
PORT_Memcpy(fragment, msg->data, 6);
/* Offset */
fragment[6] = (fragment_offset >> 16) & 0xff;
fragment[7] = (fragment_offset >> 8) & 0xff;
fragment[8] = (fragment_offset) & 0xff;
/* Fragment length */
fragment[9] = (fragment_len >> 16) & 0xff;
fragment[10] = (fragment_len >> 8) & 0xff;
fragment[11] = (fragment_len) & 0xff;
PORT_Memcpy(fragment + 12, content + fragment_offset,
fragment_len);
/*
* Send the record. We do this in two stages
* 1. Encrypt
*/
sent = ssl3_SendRecord(ss, msg->epoch, msg->type,
fragment, fragment_len + 12,
ssl_SEND_FLAG_FORCE_INTO_BUFFER |
ssl_SEND_FLAG_USE_EPOCH);
if (sent != (fragment_len + 12)) {
rv = SECFailure;
if (sent != -1) {
PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
}
break;
}
/* 2. Flush */
rv = dtls_SendSavedWriteData(ss);
if (rv != SECSuccess)
break;
fragment_offset += fragment_len;
}
}
}
/* Finally, we need to flush */
if (rv == SECSuccess)
rv = dtls_SendSavedWriteData(ss);
/* Give up the locks */
ssl_ReleaseSpecReadLock(ss);
ssl_ReleaseXmitBufLock(ss);
return rv;
}
/* Flush the data in the pendingBuf and update the max message sent
* so we can adjust the MTU estimate if we need to.
* Wrapper for ssl_SendSavedWriteData.
*
* Called from dtls_TransmitMessageFlight()
*/
static
SECStatus dtls_SendSavedWriteData(sslSocket *ss)
{
PRInt32 sent;
sent = ssl_SendSavedWriteData(ss);
if (sent < 0)
return SECFailure;
/* We should always have complete writes b/c datagram sockets
* don't really block */
if (ss->pendingBuf.len > 0) {
ssl_MapLowLevelError(SSL_ERROR_SOCKET_WRITE_FAILURE);
return SECFailure;
}
/* Update the largest message sent so we can adjust the MTU
* estimate if necessary */
if (sent > ss->ssl3.hs.maxMessageSent)
ss->ssl3.hs.maxMessageSent = sent;
return SECSuccess;
}
/* Compress, MAC, encrypt a DTLS record. Allows specification of
* the epoch using epoch value. If use_epoch is PR_TRUE then
* we use the provided epoch. If use_epoch is PR_FALSE then
* whatever the current value is in effect is used.
*
* Called from ssl3_SendRecord()
*/
SECStatus
dtls_CompressMACEncryptRecord(sslSocket * ss,
DTLSEpoch epoch,
PRBool use_epoch,
SSL3ContentType type,
const SSL3Opaque * pIn,
PRUint32 contentLen,
sslBuffer * wrBuf)
{
SECStatus rv = SECFailure;
ssl3CipherSpec * cwSpec;
ssl_GetSpecReadLock(ss); /********************************/
/* The reason for this switch-hitting code is that we might have
* a flight of records spanning an epoch boundary, e.g.,
*
* ClientKeyExchange (epoch = 0)
* ChangeCipherSpec (epoch = 0)
* Finished (epoch = 1)
*
* Thus, each record needs a different cipher spec. The information
* about which epoch to use is carried with the record.
*/
if (use_epoch) {
if (ss->ssl3.cwSpec->epoch == epoch)
cwSpec = ss->ssl3.cwSpec;
else if (ss->ssl3.pwSpec->epoch == epoch)
cwSpec = ss->ssl3.pwSpec;
else
cwSpec = NULL;
} else {
cwSpec = ss->ssl3.cwSpec;
}
if (cwSpec) {
rv = ssl3_CompressMACEncryptRecord(cwSpec, ss->sec.isServer, PR_TRUE,
PR_FALSE, type, pIn, contentLen,
wrBuf);
} else {
PR_NOT_REACHED("Couldn't find a cipher spec matching epoch");
PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
}
ssl_ReleaseSpecReadLock(ss); /************************************/
return rv;
}
/* Start a timer
*
* Called from:
* dtls_HandleHandshake()
* dtls_FlushHAndshake()
* dtls_RestartTimer()
*/
SECStatus
dtls_StartTimer(sslSocket *ss, DTLSTimerCb cb)
{
PORT_Assert(ss->ssl3.hs.rtTimerCb == NULL);
ss->ssl3.hs.rtTimerStarted = PR_IntervalNow();
ss->ssl3.hs.rtTimerCb = cb;
return SECSuccess;
}
/* Restart a timer with optional backoff
*
* Called from dtls_RetransmitTimerExpiredCb()
*/
SECStatus
dtls_RestartTimer(sslSocket *ss, PRBool backoff, DTLSTimerCb cb)
{
if (backoff) {
ss->ssl3.hs.rtTimeoutMs *= 2;
if (ss->ssl3.hs.rtTimeoutMs > MAX_DTLS_TIMEOUT_MS)
ss->ssl3.hs.rtTimeoutMs = MAX_DTLS_TIMEOUT_MS;
}
return dtls_StartTimer(ss, cb);
}
/* Cancel a pending timer
*
* Called from:
* dtls_HandleHandshake()
* dtls_CheckTimer()
*/
void
dtls_CancelTimer(sslSocket *ss)
{
PORT_Assert(ss->opt.noLocks || ssl_HaveRecvBufLock(ss));
ss->ssl3.hs.rtTimerCb = NULL;
}
/* Check the pending timer and fire the callback if it expired
*
* Called from ssl3_GatherCompleteHandshake()
*/
void
dtls_CheckTimer(sslSocket *ss)
{
if (!ss->ssl3.hs.rtTimerCb)
return;
if ((PR_IntervalNow() - ss->ssl3.hs.rtTimerStarted) >
PR_MillisecondsToInterval(ss->ssl3.hs.rtTimeoutMs)) {
/* Timer has expired */
DTLSTimerCb cb = ss->ssl3.hs.rtTimerCb;
/* Cancel the timer so that we can call the CB safely */
dtls_CancelTimer(ss);
/* Now call the CB */
cb(ss);
}
}
/* The callback to fire when the holddown timer for the Finished
* message expires and we can delete it
*
* Called from dtls_CheckTimer()
*/
void
dtls_FinishedTimerCb(sslSocket *ss)
{
ssl3_DestroyCipherSpec(ss->ssl3.pwSpec, PR_FALSE);
}
/* Cancel the Finished hold-down timer and destroy the
* pending cipher spec. Note that this means that
* successive rehandshakes will fail if the Finished is
* lost.
*
* XXX OK for now. Figure out how to handle the combination
* of Finished lost and rehandshake
*/
void
dtls_RehandshakeCleanup(sslSocket *ss)
{
dtls_CancelTimer(ss);
ssl3_DestroyCipherSpec(ss->ssl3.pwSpec, PR_FALSE);
ss->ssl3.hs.sendMessageSeq = 0;
ss->ssl3.hs.recvMessageSeq = 0;
}
/* Set the MTU to the next step less than or equal to the
* advertised value. Also used to downgrade the MTU by
* doing dtls_SetMTU(ss, biggest packet set).
*
* Passing 0 means set this to the largest MTU known
* (effectively resetting the PMTU backoff value).
*
* Called by:
* ssl3_InitState()
* dtls_RetransmitTimerExpiredCb()
*/
void
dtls_SetMTU(sslSocket *ss, PRUint16 advertised)
{
int i;
if (advertised == 0) {
ss->ssl3.mtu = COMMON_MTU_VALUES[0];
SSL_TRC(30, ("Resetting MTU to %d", ss->ssl3.mtu));
return;
}
for (i = 0; i < PR_ARRAY_SIZE(COMMON_MTU_VALUES); i++) {
if (COMMON_MTU_VALUES[i] <= advertised) {
ss->ssl3.mtu = COMMON_MTU_VALUES[i];
SSL_TRC(30, ("Resetting MTU to %d", ss->ssl3.mtu));
return;
}
}
/* Fallback */
ss->ssl3.mtu = COMMON_MTU_VALUES[PR_ARRAY_SIZE(COMMON_MTU_VALUES)-1];
SSL_TRC(30, ("Resetting MTU to %d", ss->ssl3.mtu));
}
/* Called from ssl3_HandleHandshakeMessage() when it has deciphered a
* DTLS hello_verify_request
* Caller must hold Handshake and RecvBuf locks.
*/
SECStatus
dtls_HandleHelloVerifyRequest(sslSocket *ss, SSL3Opaque *b, PRUint32 length)
{
int errCode = SSL_ERROR_RX_MALFORMED_HELLO_VERIFY_REQUEST;
SECStatus rv;
PRInt32 temp;
SECItem cookie = {siBuffer, NULL, 0};
SSL3AlertDescription desc = illegal_parameter;
SSL_TRC(3, ("%d: SSL3[%d]: handle hello_verify_request handshake",
SSL_GETPID(), ss->fd));
PORT_Assert(ss->opt.noLocks || ssl_HaveRecvBufLock(ss));
PORT_Assert(ss->opt.noLocks || ssl_HaveSSL3HandshakeLock(ss));
if (ss->ssl3.hs.ws != wait_server_hello) {
errCode = SSL_ERROR_RX_UNEXPECTED_HELLO_VERIFY_REQUEST;
desc = unexpected_message;
goto alert_loser;
}
/* The version */
temp = ssl3_ConsumeHandshakeNumber(ss, 2, &b, &length);
if (temp < 0) {
goto loser; /* alert has been sent */
}
if (temp != SSL_LIBRARY_VERSION_DTLS_1_0_WIRE &&
temp != SSL_LIBRARY_VERSION_DTLS_1_2_WIRE) {
goto alert_loser;
}
/* The cookie */
rv = ssl3_ConsumeHandshakeVariable(ss, &cookie, 1, &b, &length);
if (rv != SECSuccess) {
goto loser; /* alert has been sent */
}
if (cookie.len > DTLS_COOKIE_BYTES) {
desc = decode_error;
goto alert_loser; /* malformed. */
}
PORT_Memcpy(ss->ssl3.hs.cookie, cookie.data, cookie.len);
ss->ssl3.hs.cookieLen = cookie.len;
ssl_GetXmitBufLock(ss); /*******************************/
/* Now re-send the client hello */
rv = ssl3_SendClientHello(ss, PR_TRUE);
ssl_ReleaseXmitBufLock(ss); /*******************************/
if (rv == SECSuccess)
return rv;
alert_loser:
(void)SSL3_SendAlert(ss, alert_fatal, desc);
loser:
errCode = ssl_MapLowLevelError(errCode);
return SECFailure;
}
/* Initialize the DTLS anti-replay window
*
* Called from:
* ssl3_SetupPendingCipherSpec()
* ssl3_InitCipherSpec()
*/
void
dtls_InitRecvdRecords(DTLSRecvdRecords *records)
{
PORT_Memset(records->data, 0, sizeof(records->data));
records->left = 0;
records->right = DTLS_RECVD_RECORDS_WINDOW - 1;
}
/*
* Has this DTLS record been received? Return values are:
* -1 -- out of range to the left
* 0 -- not received yet
* 1 -- replay
*
* Called from: dtls_HandleRecord()
*/
int
dtls_RecordGetRecvd(DTLSRecvdRecords *records, PRUint64 seq)
{
PRUint64 offset;
/* Out of range to the left */
if (seq < records->left) {
return -1;
}
/* Out of range to the right; since we advance the window on
* receipt, that means that this packet has not been received
* yet */
if (seq > records->right)
return 0;
offset = seq % DTLS_RECVD_RECORDS_WINDOW;
return !!(records->data[offset / 8] & (1 << (offset % 8)));
}
/* Update the DTLS anti-replay window
*
* Called from ssl3_HandleRecord()
*/
void
dtls_RecordSetRecvd(DTLSRecvdRecords *records, PRUint64 seq)
{
PRUint64 offset;
if (seq < records->left)
return;
if (seq > records->right) {
PRUint64 new_left;
PRUint64 new_right;
PRUint64 right;
/* Slide to the right; this is the tricky part
*
* 1. new_top is set to have room for seq, on the
* next byte boundary by setting the right 8
* bits of seq
* 2. new_left is set to compensate.
* 3. Zero all bits between top and new_top. Since
* this is a ring, this zeroes everything as-yet
* unseen. Because we always operate on byte
* boundaries, we can zero one byte at a time
*/
new_right = seq | 0x07;
new_left = (new_right - DTLS_RECVD_RECORDS_WINDOW) + 1;
for (right = records->right + 8; right <= new_right; right += 8) {
offset = right % DTLS_RECVD_RECORDS_WINDOW;
records->data[offset / 8] = 0;
}
records->right = new_right;
records->left = new_left;
}
offset = seq % DTLS_RECVD_RECORDS_WINDOW;
records->data[offset / 8] |= (1 << (offset % 8));
}
SECStatus
DTLS_GetHandshakeTimeout(PRFileDesc *socket, PRIntervalTime *timeout)
{
sslSocket * ss = NULL;
PRIntervalTime elapsed;
PRIntervalTime desired;
ss = ssl_FindSocket(socket);
if (!ss)
return SECFailure;
if (!IS_DTLS(ss))
return SECFailure;
if (!ss->ssl3.hs.rtTimerCb)
return SECFailure;
elapsed = PR_IntervalNow() - ss->ssl3.hs.rtTimerStarted;
desired = PR_MillisecondsToInterval(ss->ssl3.hs.rtTimeoutMs);
if (elapsed > desired) {
/* Timer expired */
*timeout = PR_INTERVAL_NO_WAIT;
} else {
*timeout = desired - elapsed;
}
return SECSuccess;
}
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