Merge branch 'NSS-335'

1 files changed, 457 insertions, 0 deletions

diff --git a/security/nss/lib/ssl/dtls13con.c b/security/nss/lib/ssl/dtls13con.c
new file mode 100644
index 000000000..aba0f62ab
--- /dev/null
+++ b/security/nss/lib/ssl/dtls13con.c
@@ -0,0 +1,457 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* 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 1.3 Protocol
+ */
+
+#include "ssl.h"
+#include "sslimpl.h"
+#include "sslproto.h"
+
+/* DTLS 1.3 Record map for ACK processing.
+ * This represents a single fragment, so a record which includes
+ * multiple fragments will have one entry for each fragment on the
+ * sender. We use the same structure on the receiver for convenience
+ * but the only value we actually use is |record|.
+ */
+typedef struct DTLSHandshakeRecordEntryStr {
+    PRCList link;
+    PRUint16 messageSeq;      /* The handshake message sequence number. */
+    PRUint32 offset;          /* The offset into the handshake message. */
+    PRUint32 length;          /* The length of the fragment. */
+    sslSequenceNumber record; /* The record (includes epoch). */
+    PRBool acked;             /* Has this packet been acked. */
+} DTLSHandshakeRecordEntry;
+
+/* Combine the epoch and sequence number into a single value. */
+static inline sslSequenceNumber
+dtls_CombineSequenceNumber(DTLSEpoch epoch, sslSequenceNumber seqNum)
+{
+    PORT_Assert(seqNum <= RECORD_SEQ_MAX);
+    return ((sslSequenceNumber)epoch << 48) | seqNum;
+}
+
+SECStatus
+dtls13_RememberFragment(sslSocket *ss,
+                        PRCList *list,
+                        PRUint32 sequence,
+                        PRUint32 offset,
+                        PRUint32 length,
+                        DTLSEpoch epoch,
+                        sslSequenceNumber record)
+{
+    DTLSHandshakeRecordEntry *entry;
+
+    PORT_Assert(IS_DTLS(ss));
+    /* We should never send an empty fragment with offset > 0. */
+    PORT_Assert(length || !offset);
+
+    if (!tls13_MaybeTls13(ss)) {
+        return SECSuccess;
+    }
+
+    SSL_TRC(20, ("%d: SSL3[%d]: %s remembering %s record=%llx msg=%d offset=%d",
+                 SSL_GETPID(), ss->fd,
+                 SSL_ROLE(ss),
+                 list == &ss->ssl3.hs.dtlsSentHandshake ? "sent" : "received",
+                 dtls_CombineSequenceNumber(epoch, record), sequence, offset));
+
+    entry = PORT_ZAlloc(sizeof(DTLSHandshakeRecordEntry));
+    if (!entry) {
+        return SECFailure;
+    }
+
+    entry->messageSeq = sequence;
+    entry->offset = offset;
+    entry->length = length;
+    entry->record = dtls_CombineSequenceNumber(epoch, record);
+    entry->acked = PR_FALSE;
+
+    PR_APPEND_LINK(&entry->link, list);
+
+    return SECSuccess;
+}
+
+SECStatus
+dtls13_SendAck(sslSocket *ss)
+{
+    sslBuffer buf = SSL_BUFFER_EMPTY;
+    SECStatus rv = SECSuccess;
+    PRCList *cursor;
+    PRInt32 sent;
+
+    SSL_TRC(10, ("%d: SSL3[%d]: Sending ACK",
+                 SSL_GETPID(), ss->fd));
+
+    for (cursor = PR_LIST_HEAD(&ss->ssl3.hs.dtlsRcvdHandshake);
+         cursor != &ss->ssl3.hs.dtlsRcvdHandshake;
+         cursor = PR_NEXT_LINK(cursor)) {
+        DTLSHandshakeRecordEntry *entry = (DTLSHandshakeRecordEntry *)cursor;
+
+        SSL_TRC(10, ("%d: SSL3[%d]: ACK for record=%llx",
+                     SSL_GETPID(), ss->fd, entry->record));
+        rv = sslBuffer_AppendNumber(&buf, entry->record, 8);
+        if (rv != SECSuccess) {
+            goto loser;
+        }
+    }
+
+    ssl_GetXmitBufLock(ss);
+    sent = ssl3_SendRecord(ss, NULL, content_ack,
+                           buf.buf, buf.len, 0);
+    ssl_ReleaseXmitBufLock(ss);
+    if (sent != buf.len) {
+        rv = SECFailure;
+        if (sent != -1) {
+            PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
+        }
+    }
+
+loser:
+    sslBuffer_Clear(&buf);
+    return rv;
+}
+
+void
+dtls13_SendAckCb(sslSocket *ss)
+{
+    if (!IS_DTLS(ss)) {
+        return;
+    }
+    (void)dtls13_SendAck(ss);
+}
+
+/* Zero length messages are very simple to check. */
+static PRBool
+dtls_IsEmptyMessageAcknowledged(sslSocket *ss, PRUint16 msgSeq, PRUint32 offset)
+{
+    PRCList *cursor;
+
+    for (cursor = PR_LIST_HEAD(&ss->ssl3.hs.dtlsSentHandshake);
+         cursor != &ss->ssl3.hs.dtlsSentHandshake;
+         cursor = PR_NEXT_LINK(cursor)) {
+        DTLSHandshakeRecordEntry *entry = (DTLSHandshakeRecordEntry *)cursor;
+        if (!entry->acked || msgSeq != entry->messageSeq) {
+            continue;
+        }
+        /* Empty fragments are always offset 0. */
+        if (entry->length == 0) {
+            PORT_Assert(!entry->offset);
+            return PR_TRUE;
+        }
+    }
+    return PR_FALSE;
+}
+
+/* Take a range starting at |*start| and that start forwards based on the
+ * contents of the acknowedgement in |entry|. Only move if the acknowledged
+ * range overlaps |*start|. Return PR_TRUE if it moves. */
+static PRBool
+dtls_MoveUnackedStartForward(DTLSHandshakeRecordEntry *entry, PRUint32 *start)
+{
+    /* This entry starts too late. */
+    if (*start < entry->offset) {
+        return PR_FALSE;
+    }
+    /* This entry ends too early. */
+    if (*start >= entry->offset + entry->length) {
+        return PR_FALSE;
+    }
+    *start = entry->offset + entry->length;
+    return PR_TRUE;
+}
+
+/* Take a range ending at |*end| and move that end backwards based on the
+ * contents of the acknowedgement in |entry|. Only move if the acknowledged
+ * range overlaps |*end|. Return PR_TRUE if it moves. */
+static PRBool
+dtls_MoveUnackedEndBackward(DTLSHandshakeRecordEntry *entry, PRUint32 *end)
+{
+    /* This entry ends too early. */
+    if (*end > entry->offset + entry->length) {
+        return PR_FALSE;
+    }
+    /* This entry starts too late. */
+    if (*end <= entry->offset) {
+        return PR_FALSE;
+    }
+    *end = entry->offset;
+    return PR_TRUE;
+}
+
+/* Get the next contiguous range of unacknowledged bytes from the handshake
+ * message identified by |msgSeq|.  The search starts at the offset in |offset|.
+ * |len| contains the full length of the message.
+ *
+ * Returns PR_TRUE if there is an unacknowledged range.  In this case, values at
+ * |start| and |end| are modified to contain the range.
+ *
+ * Returns PR_FALSE if the message is entirely acknowledged from |offset|
+ * onwards.
+ */
+PRBool
+dtls_NextUnackedRange(sslSocket *ss, PRUint16 msgSeq, PRUint32 offset,
+                      PRUint32 len, PRUint32 *startOut, PRUint32 *endOut)
+{
+    PRCList *cur_p;
+    PRBool done = PR_FALSE;
+    DTLSHandshakeRecordEntry *entry;
+    PRUint32 start;
+    PRUint32 end;
+
+    PORT_Assert(IS_DTLS(ss));
+
+    *startOut = offset;
+    *endOut = len;
+    if (!tls13_MaybeTls13(ss)) {
+        return PR_TRUE;
+    }
+
+    /* The message is empty. Use a simple search. */
+    if (!len) {
+        PORT_Assert(!offset);
+        return !dtls_IsEmptyMessageAcknowledged(ss, msgSeq, offset);
+    }
+
+    /* This iterates multiple times over the acknowledgments and only terminates
+     * when an entire iteration happens without start or end moving.  If that
+     * happens without start and end crossing each other, then there is a range
+     * of unacknowledged data.  If they meet, then the message is fully
+     * acknowledged. */
+    start = offset;
+    end = len;
+    while (!done) {
+        done = PR_TRUE;
+        for (cur_p = PR_LIST_HEAD(&ss->ssl3.hs.dtlsSentHandshake);
+             cur_p != &ss->ssl3.hs.dtlsSentHandshake;
+             cur_p = PR_NEXT_LINK(cur_p)) {
+            entry = (DTLSHandshakeRecordEntry *)cur_p;
+            if (!entry->acked || msgSeq != entry->messageSeq) {
+                continue;
+            }
+
+            if (dtls_MoveUnackedStartForward(entry, &start) ||
+                dtls_MoveUnackedEndBackward(entry, &end)) {
+                if (start >= end) {
+                    /* The message is all acknowledged. */
+                    return PR_FALSE;
+                }
+                /* Start over again and keep going until we don't move either
+                 * start or end. */
+                done = PR_FALSE;
+                break;
+            }
+        }
+    }
+    PORT_Assert(start < end);
+
+    *startOut = start;
+    *endOut = end;
+    return PR_TRUE;
+}
+
+SECStatus
+dtls13_SetupAcks(sslSocket *ss)
+{
+    if (ss->version < SSL_LIBRARY_VERSION_TLS_1_3) {
+        return SECSuccess;
+    }
+
+    if (ss->ssl3.hs.endOfFlight) {
+        dtls_CancelTimer(ss, ss->ssl3.hs.ackTimer);
+
+        if (ss->ssl3.hs.ws == idle_handshake && ss->sec.isServer) {
+            SSL_TRC(10, ("%d: SSL3[%d]: dtls_HandleHandshake, sending ACK",
+                         SSL_GETPID(), ss->fd));
+            return dtls13_SendAck(ss);
+        }
+        return SECSuccess;
+    }
+
+    /* We need to send an ACK. */
+    if (!ss->ssl3.hs.ackTimer->cb) {
+        /* We're not armed, so arm. */
+        SSL_TRC(10, ("%d: SSL3[%d]: dtls_HandleHandshake, arming ack timer",
+                     SSL_GETPID(), ss->fd));
+        return dtls_StartTimer(ss, ss->ssl3.hs.ackTimer,
+                               DTLS_RETRANSMIT_INITIAL_MS / 4,
+                               dtls13_SendAckCb);
+    }
+    /* The ack timer is already armed, so just return. */
+    return SECSuccess;
+}
+
+/*
+ * Special case processing for out-of-epoch records.
+ * This can only handle ACKs for now and everything else generates
+ * an error. In future, may also handle KeyUpdate.
+ *
+ * The error checking here is as follows:
+ *
+ * - If it's not encrypted, out of epoch stuff is just discarded.
+ * - If it's encrypted, out of epoch stuff causes an error.
+ */
+SECStatus
+dtls13_HandleOutOfEpochRecord(sslSocket *ss, const ssl3CipherSpec *spec,
+                              SSL3ContentType rType,
+                              sslBuffer *databuf)
+{
+    SECStatus rv;
+    sslBuffer buf = *databuf;
+
+    databuf->len = 0; /* Discard data whatever happens. */
+    PORT_Assert(IS_DTLS(ss));
+    PORT_Assert(ss->version >= SSL_LIBRARY_VERSION_TLS_1_3);
+    /* Can't happen, but double check. */
+    if (!IS_DTLS(ss) || (ss->version < SSL_LIBRARY_VERSION_TLS_1_3)) {
+        tls13_FatalError(ss, SEC_ERROR_LIBRARY_FAILURE, internal_error);
+        return SECFailure;
+    }
+    SSL_TRC(10, ("%d: DTLS13[%d]: handle out of epoch record: type=%d", SSL_GETPID(),
+                 ss->fd, rType));
+
+    if (rType == content_ack) {
+        ssl_GetSSL3HandshakeLock(ss);
+        rv = dtls13_HandleAck(ss, &buf);
+        ssl_ReleaseSSL3HandshakeLock(ss);
+        PORT_Assert(databuf->len == 0);
+        return rv;
+    }
+
+    switch (spec->epoch) {
+        case TrafficKeyClearText:
+            /* Drop. */
+            return SECSuccess;
+
+        case TrafficKeyHandshake:
+            /* Drop out of order handshake messages, but if we are the
+             * server, we might have processed the client's Finished and
+             * moved on to application data keys, but the client has
+             * retransmitted Finished (e.g., because our ACK got lost.)
+             * We just retransmit the previous Finished to let the client
+             * complete. */
+            if (rType == content_handshake) {
+                if ((ss->sec.isServer) &&
+                    (ss->ssl3.hs.ws == idle_handshake)) {
+                    PORT_Assert(dtls_TimerActive(ss, ss->ssl3.hs.hdTimer));
+                    return dtls13_SendAck(ss);
+                }
+                return SECSuccess;
+            }
+
+            /* This isn't a handshake record, so shouldn't be encrypted
+             * under the handshake key. */
+            break;
+
+        default:
+            /* Any other epoch is forbidden. */
+            break;
+    }
+
+    SSL_TRC(10, ("%d: SSL3[%d]: unexpected out of epoch record type %d", SSL_GETPID(),
+                 ss->fd, rType));
+
+    (void)SSL3_SendAlert(ss, alert_fatal, illegal_parameter);
+    PORT_SetError(SSL_ERROR_RX_UNKNOWN_RECORD_TYPE);
+    return SECFailure;
+}
+
+SECStatus
+dtls13_HandleAck(sslSocket *ss, sslBuffer *databuf)
+{
+    PRUint8 *b = databuf->buf;
+    PRUint32 l = databuf->len;
+    SECStatus rv;
+
+    /* Ensure we don't loop. */
+    databuf->len = 0;
+
+    PORT_Assert(IS_DTLS(ss));
+    if (!tls13_MaybeTls13(ss)) {
+        tls13_FatalError(ss, SSL_ERROR_RX_UNKNOWN_RECORD_TYPE, illegal_parameter);
+        return SECSuccess;
+    }
+
+    SSL_TRC(10, ("%d: SSL3[%d]: Handling ACK", SSL_GETPID(), ss->fd));
+    while (l > 0) {
+        PRUint64 seq;
+        PRCList *cursor;
+
+        rv = ssl3_ConsumeHandshakeNumber64(ss, &seq, 8, &b, &l);
+        if (rv != SECSuccess) {
+            return SECFailure;
+        }
+
+        for (cursor = PR_LIST_HEAD(&ss->ssl3.hs.dtlsSentHandshake);
+             cursor != &ss->ssl3.hs.dtlsSentHandshake;
+             cursor = PR_NEXT_LINK(cursor)) {
+            DTLSHandshakeRecordEntry *entry = (DTLSHandshakeRecordEntry *)cursor;
+
+            if (entry->record == seq) {
+                SSL_TRC(10, (
+                                "%d: SSL3[%d]: Marking record=%llx message %d offset %d length=%d as ACKed",
+                                SSL_GETPID(), ss->fd,
+                                seq, entry->messageSeq, entry->offset, entry->length));
+                entry->acked = PR_TRUE;
+            }
+        }
+    }
+
+    /* Try to flush. */
+    rv = dtls_TransmitMessageFlight(ss);
+    if (rv != SECSuccess) {
+        return SECFailure;
+    }
+
+    /* Reset the retransmit timer. */
+    if (ss->ssl3.hs.rtTimer->cb) {
+        (void)dtls_RestartTimer(ss, ss->ssl3.hs.rtTimer);
+    }
+
+    /* If there are no more messages to send, cleanup. */
+    if (PR_CLIST_IS_EMPTY(&ss->ssl3.hs.lastMessageFlight)) {
+        SSL_TRC(10, ("%d: SSL3[%d]: No more unacked handshake messages",
+                     SSL_GETPID(), ss->fd));
+
+        dtls_CancelTimer(ss, ss->ssl3.hs.rtTimer);
+        ssl_ClearPRCList(&ss->ssl3.hs.dtlsSentHandshake, NULL);
+        /* If the handshake is finished, and we're the client then
+         * also clean up the handshake read cipher spec. Any ACKs
+         * we receive will be with the application data cipher spec.
+         * The server needs to keep the handshake cipher spec around
+         * for the holddown period to process retransmitted Finisheds.
+         */
+        if (!ss->sec.isServer && (ss->ssl3.hs.ws == idle_handshake)) {
+            ssl_CipherSpecReleaseByEpoch(ss, CipherSpecRead,
+                                         TrafficKeyHandshake);
+        }
+    }
+    return SECSuccess;
+}
+
+/* Clean up the read timer for the handshake cipher suites on the
+ * server.
+ *
+ * In DTLS 1.3, the client speaks last (Finished), and will retransmit
+ * until the server ACKs that message (using application data cipher
+ * suites). I.e.,
+ *
+ * - The client uses the retransmit timer and retransmits using the
+ *   saved write handshake cipher suite.
+ * - The server keeps the saved read handshake cipher suite around
+ *   for the holddown period in case it needs to read the Finished.
+ *
+ * After the holddown period, the server assumes the client is happy
+ * and discards the handshake read cipher suite.
+ */
+void
+dtls13_HolddownTimerCb(sslSocket *ss)
+{
+    SSL_TRC(10, ("%d: SSL3[%d]: holddown timer fired",
+                 SSL_GETPID(), ss->fd));
+    ssl_CipherSpecReleaseByEpoch(ss, CipherSpecRead, TrafficKeyHandshake);
+    ssl_ClearPRCList(&ss->ssl3.hs.dtlsRcvdHandshake, NULL);
+}