Add m-esr52 at 52.6.0

1 files changed, 1169 insertions, 0 deletions

diff --git a/security/nss/lib/ssl/tls13exthandle.c b/security/nss/lib/ssl/tls13exthandle.c
new file mode 100644
index 000000000..be93b97db
--- /dev/null
+++ b/security/nss/lib/ssl/tls13exthandle.c
@@ -0,0 +1,1169 @@
+/* -*- 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/. */
+
+#include "nssrenam.h"
+#include "nss.h"
+#include "ssl.h"
+#include "sslproto.h"
+#include "sslimpl.h"
+#include "pk11pub.h"
+#include "ssl3ext.h"
+#include "ssl3exthandle.h"
+#include "tls13exthandle.h"
+
+PRInt32
+tls13_ServerSendStatusRequestXtn(
+    const sslSocket *ss,
+    TLSExtensionData *xtnData,
+    PRBool append,
+    PRUint32 maxBytes)
+{
+    PRInt32 extension_length;
+    const sslServerCert *serverCert = ss->sec.serverCert;
+    const SECItem *item;
+    SECStatus rv;
+
+    if (!serverCert->certStatusArray ||
+        !serverCert->certStatusArray->len) {
+        return 0;
+    }
+
+    item = &serverCert->certStatusArray->items[0];
+
+    /* Only send the first entry. */
+    extension_length = 2 + 2 + 1 /* status_type */ + 3 + item->len;
+    if (maxBytes < (PRUint32)extension_length) {
+        return 0;
+    }
+    if (append) {
+        /* extension_type */
+        rv = ssl3_ExtAppendHandshakeNumber(ss, ssl_cert_status_xtn, 2);
+        if (rv != SECSuccess)
+            return -1;
+        /* length of extension_data */
+        rv = ssl3_ExtAppendHandshakeNumber(ss, extension_length - 4, 2);
+        if (rv != SECSuccess)
+            return -1;
+        /* status_type == ocsp */
+        rv = ssl3_ExtAppendHandshakeNumber(ss, 1 /*ocsp*/, 1);
+        if (rv != SECSuccess)
+            return rv; /* err set by AppendHandshake. */
+        /* opaque OCSPResponse<1..2^24-1> */
+        rv = ssl3_ExtAppendHandshakeVariable(ss, item->data, item->len, 3);
+        if (rv != SECSuccess)
+            return rv; /* err set by AppendHandshake. */
+    }
+
+    return extension_length;
+}
+
+/*
+ *     [draft-ietf-tls-tls13-11] Section 6.3.2.3.
+ *
+ *     struct {
+ *         NamedGroup group;
+ *         opaque key_exchange<1..2^16-1>;
+ *     } KeyShareEntry;
+ *
+ *     struct {
+ *         select (role) {
+ *             case client:
+ *                 KeyShareEntry client_shares<4..2^16-1>;
+ *
+ *             case server:
+ *                 KeyShareEntry server_share;
+ *         }
+ *     } KeyShare;
+ *
+ * DH is Section 6.3.2.3.1.
+ *
+ *     opaque dh_Y<1..2^16-1>;
+ *
+ * ECDH is Section 6.3.2.3.2.
+ *
+ *     opaque point <1..2^8-1>;
+ */
+static PRUint32
+tls13_SizeOfKeyShareEntry(const SECKEYPublicKey *pubKey)
+{
+    /* Size = NamedGroup(2) + length(2) + opaque<?> share */
+    switch (pubKey->keyType) {
+        case ecKey:
+            return 2 + 2 + pubKey->u.ec.publicValue.len;
+        case dhKey:
+            return 2 + 2 + pubKey->u.dh.prime.len;
+        default:
+            PORT_Assert(0);
+    }
+    return 0;
+}
+
+static PRUint32
+tls13_SizeOfClientKeyShareExtension(const sslSocket *ss)
+{
+    PRCList *cursor;
+    /* Size is: extension(2) + extension_len(2) + client_shares(2) */
+    PRUint32 size = 2 + 2 + 2;
+    for (cursor = PR_NEXT_LINK(&ss->ephemeralKeyPairs);
+         cursor != &ss->ephemeralKeyPairs;
+         cursor = PR_NEXT_LINK(cursor)) {
+        sslEphemeralKeyPair *keyPair = (sslEphemeralKeyPair *)cursor;
+        size += tls13_SizeOfKeyShareEntry(keyPair->keys->pubKey);
+    }
+    return size;
+}
+
+static SECStatus
+tls13_EncodeKeyShareEntry(const sslSocket *ss, const sslEphemeralKeyPair *keyPair)
+{
+    SECStatus rv;
+    SECKEYPublicKey *pubKey = keyPair->keys->pubKey;
+    unsigned int size = tls13_SizeOfKeyShareEntry(pubKey);
+
+    rv = ssl3_ExtAppendHandshakeNumber(ss, keyPair->group->name, 2);
+    if (rv != SECSuccess)
+        return rv;
+    rv = ssl3_ExtAppendHandshakeNumber(ss, size - 4, 2);
+    if (rv != SECSuccess)
+        return rv;
+
+    switch (pubKey->keyType) {
+        case ecKey:
+            rv = tls13_EncodeECDHEKeyShareKEX(ss, pubKey);
+            break;
+        case dhKey:
+            rv = ssl_AppendPaddedDHKeyShare(ss, pubKey, PR_FALSE);
+            break;
+        default:
+            PORT_Assert(0);
+            PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
+            break;
+    }
+
+    return rv;
+}
+
+PRInt32
+tls13_ClientSendKeyShareXtn(const sslSocket *ss, TLSExtensionData *xtnData, PRBool append,
+                            PRUint32 maxBytes)
+{
+    PRUint32 extension_length;
+
+    if (ss->vrange.max < SSL_LIBRARY_VERSION_TLS_1_3) {
+        return 0;
+    }
+
+    /* Optimistically try to send an ECDHE key using the
+     * preexisting key (in future will be keys) */
+    SSL_TRC(3, ("%d: TLS13[%d]: send client key share xtn",
+                SSL_GETPID(), ss->fd));
+
+    extension_length = tls13_SizeOfClientKeyShareExtension(ss);
+    if (maxBytes < extension_length) {
+        PORT_Assert(0);
+        return 0;
+    }
+
+    if (append) {
+        SECStatus rv;
+        PRCList *cursor;
+
+        rv = ssl3_ExtAppendHandshakeNumber(ss, ssl_tls13_key_share_xtn, 2);
+        if (rv != SECSuccess)
+            goto loser;
+
+        /* The extension length */
+        rv = ssl3_ExtAppendHandshakeNumber(ss, extension_length - 4, 2);
+        if (rv != SECSuccess)
+            goto loser;
+
+        /* The length of KeyShares */
+        rv = ssl3_ExtAppendHandshakeNumber(ss, extension_length - 6, 2);
+        if (rv != SECSuccess)
+            goto loser;
+
+        for (cursor = PR_NEXT_LINK(&ss->ephemeralKeyPairs);
+             cursor != &ss->ephemeralKeyPairs;
+             cursor = PR_NEXT_LINK(cursor)) {
+            sslEphemeralKeyPair *keyPair = (sslEphemeralKeyPair *)cursor;
+            rv = tls13_EncodeKeyShareEntry(ss, keyPair);
+            if (rv != SECSuccess)
+                goto loser;
+        }
+
+        xtnData->advertised[xtnData->numAdvertised++] =
+            ssl_tls13_key_share_xtn;
+    }
+
+    return extension_length;
+
+loser:
+    return -1;
+}
+
+static SECStatus
+tls13_HandleKeyShareEntry(const sslSocket *ss, TLSExtensionData *xtnData, SECItem *data)
+{
+    SECStatus rv;
+    PRInt32 group;
+    const sslNamedGroupDef *groupDef;
+    TLS13KeyShareEntry *ks = NULL;
+    SECItem share = { siBuffer, NULL, 0 };
+
+    group = ssl3_ExtConsumeHandshakeNumber(ss, 2, &data->data, &data->len);
+    if (group < 0) {
+        PORT_SetError(SSL_ERROR_RX_MALFORMED_KEY_SHARE);
+        goto loser;
+    }
+    groupDef = ssl_LookupNamedGroup(group);
+    rv = ssl3_ExtConsumeHandshakeVariable(ss, &share, 2, &data->data,
+                                          &data->len);
+    if (rv != SECSuccess) {
+        goto loser;
+    }
+    /* If the group is disabled, continue. */
+    if (!groupDef) {
+        return SECSuccess;
+    }
+
+    ks = PORT_ZNew(TLS13KeyShareEntry);
+    if (!ks)
+        goto loser;
+    ks->group = groupDef;
+
+    rv = SECITEM_CopyItem(NULL, &ks->key_exchange, &share);
+    if (rv != SECSuccess)
+        goto loser;
+
+    PR_APPEND_LINK(&ks->link, &xtnData->remoteKeyShares);
+    return SECSuccess;
+
+loser:
+    if (ks)
+        tls13_DestroyKeyShareEntry(ks);
+    return SECFailure;
+}
+/* Handle an incoming KeyShare extension at the client and copy to
+ * |xtnData->remoteKeyShares| for future use. The key
+ * share is processed in tls13_HandleServerKeyShare(). */
+SECStatus
+tls13_ClientHandleKeyShareXtn(const sslSocket *ss, TLSExtensionData *xtnData, PRUint16 ex_type, SECItem *data)
+{
+    SECStatus rv;
+    PORT_Assert(PR_CLIST_IS_EMPTY(&xtnData->remoteKeyShares));
+
+    PORT_Assert(!ss->sec.isServer);
+    if (ss->version < SSL_LIBRARY_VERSION_TLS_1_3) {
+        /* This can't happen because the extension processing
+         * code filters out TLS 1.3 extensions when not in
+         * TLS 1.3 mode. */
+        PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
+        return SECFailure;
+    }
+
+    SSL_TRC(3, ("%d: SSL3[%d]: handle key_share extension",
+                SSL_GETPID(), ss->fd));
+
+    rv = tls13_HandleKeyShareEntry(ss, xtnData, data);
+    if (rv != SECSuccess) {
+        PORT_SetError(SSL_ERROR_RX_MALFORMED_KEY_SHARE);
+        return SECFailure;
+    }
+
+    if (data->len) {
+        PORT_SetError(SSL_ERROR_RX_MALFORMED_KEY_SHARE);
+        return SECFailure;
+    }
+
+    return SECSuccess;
+}
+
+SECStatus
+tls13_ClientHandleKeyShareXtnHrr(const sslSocket *ss, TLSExtensionData *xtnData, PRUint16 ex_type, SECItem *data)
+{
+    SECStatus rv;
+    PRInt32 tmp;
+    const sslNamedGroupDef *group;
+
+    PORT_Assert(!ss->sec.isServer);
+    PORT_Assert(ss->vrange.max >= SSL_LIBRARY_VERSION_TLS_1_3);
+
+    SSL_TRC(3, ("%d: SSL3[%d]: handle key_share extension in HRR",
+                SSL_GETPID(), ss->fd));
+
+    tmp = ssl3_ExtConsumeHandshakeNumber(ss, 2, &data->data, &data->len);
+    if (tmp < 0) {
+        return SECFailure; /* error code already set */
+    }
+    if (data->len) {
+        ssl3_ExtSendAlert(ss, alert_fatal, decode_error);
+        PORT_SetError(SSL_ERROR_RX_MALFORMED_HELLO_RETRY_REQUEST);
+        return SECFailure;
+    }
+
+    group = ssl_LookupNamedGroup((SSLNamedGroup)tmp);
+    /* If the group is not enabled, or we already have a share for the
+     * requested group, abort. */
+    if (!ssl_NamedGroupEnabled(ss, group) ||
+        ssl_HaveEphemeralKeyPair(ss, group)) {
+        ssl3_ExtSendAlert(ss, alert_fatal, illegal_parameter);
+        PORT_SetError(SSL_ERROR_RX_MALFORMED_HELLO_RETRY_REQUEST);
+        return SECFailure;
+    }
+
+    /* Now delete all the key shares per [draft-ietf-tls-tls13 S 4.1.2] */
+    ssl_FreeEphemeralKeyPairs(CONST_CAST(sslSocket, ss));
+
+    /* And replace with our new share. */
+    rv = tls13_CreateKeyShare(CONST_CAST(sslSocket, ss), group);
+    if (rv != SECSuccess) {
+        ssl3_ExtSendAlert(ss, alert_fatal, internal_error);
+        PORT_SetError(SEC_ERROR_KEYGEN_FAIL);
+        return SECFailure;
+    }
+
+    return SECSuccess;
+}
+
+/* Handle an incoming KeyShare extension at the server and copy to
+ * |xtnData->remoteKeyShares| for future use. The key
+ * share is processed in tls13_HandleClientKeyShare(). */
+SECStatus
+tls13_ServerHandleKeyShareXtn(const sslSocket *ss, TLSExtensionData *xtnData, PRUint16 ex_type, SECItem *data)
+{
+    SECStatus rv;
+    PRInt32 length;
+
+    PORT_Assert(ss->sec.isServer);
+    PORT_Assert(PR_CLIST_IS_EMPTY(&xtnData->remoteKeyShares));
+
+    if (ss->version < SSL_LIBRARY_VERSION_TLS_1_3) {
+        return SECSuccess;
+    }
+
+    SSL_TRC(3, ("%d: SSL3[%d]: handle key_share extension",
+                SSL_GETPID(), ss->fd));
+
+    /* Redundant length because of TLS encoding (this vector consumes
+     * the entire extension.) */
+    length = ssl3_ExtConsumeHandshakeNumber(ss, 2, &data->data,
+                                            &data->len);
+    if (length < 0)
+        goto loser;
+    if (length != data->len) {
+        /* Check for consistency */
+        PORT_SetError(SSL_ERROR_RX_MALFORMED_KEY_SHARE);
+        goto loser;
+    }
+
+    while (data->len) {
+        rv = tls13_HandleKeyShareEntry(ss, xtnData, data);
+        if (rv != SECSuccess)
+            goto loser;
+    }
+
+    /* Check that the client only offered one share if this is
+     * after HRR. */
+    if (ss->ssl3.hs.helloRetry) {
+        if (PR_PREV_LINK(&xtnData->remoteKeyShares) !=
+            PR_NEXT_LINK(&xtnData->remoteKeyShares)) {
+            PORT_SetError(SSL_ERROR_RX_MALFORMED_CLIENT_HELLO);
+            goto loser;
+        }
+    }
+
+    return SECSuccess;
+
+loser:
+    tls13_DestroyKeyShares(&xtnData->remoteKeyShares);
+    return SECFailure;
+}
+
+PRInt32
+tls13_ServerSendKeyShareXtn(const sslSocket *ss, TLSExtensionData *xtnData, PRBool append,
+                            PRUint32 maxBytes)
+{
+    PRUint32 extension_length;
+    PRUint32 entry_length;
+    SECStatus rv;
+    sslEphemeralKeyPair *keyPair;
+
+    /* There should be exactly one key share. */
+    PORT_Assert(!PR_CLIST_IS_EMPTY(&ss->ephemeralKeyPairs));
+    PORT_Assert(PR_PREV_LINK(&ss->ephemeralKeyPairs) ==
+                PR_NEXT_LINK(&ss->ephemeralKeyPairs));
+
+    keyPair = (sslEphemeralKeyPair *)PR_NEXT_LINK(&ss->ephemeralKeyPairs);
+
+    entry_length = tls13_SizeOfKeyShareEntry(keyPair->keys->pubKey);
+    extension_length = 2 + 2 + entry_length; /* Type + length + entry_length */
+    if (maxBytes < extension_length) {
+        PORT_Assert(0);
+        return 0;
+    }
+
+    if (append) {
+        rv = ssl3_ExtAppendHandshakeNumber(ss, ssl_tls13_key_share_xtn, 2);
+        if (rv != SECSuccess)
+            goto loser;
+
+        rv = ssl3_ExtAppendHandshakeNumber(ss, entry_length, 2);
+        if (rv != SECSuccess)
+            goto loser;
+
+        rv = tls13_EncodeKeyShareEntry(ss, keyPair);
+        if (rv != SECSuccess)
+            goto loser;
+    }
+
+    return extension_length;
+
+loser:
+    return -1;
+}
+
+/* Called by clients.
+ *
+ *      struct {
+ *         opaque identity<0..2^16-1>;
+ *         uint32 obfuscated_ticket_age;
+ *     } PskIdentity;
+ *
+ *     opaque PskBinderEntry<32..255>;
+ *
+ *     struct {
+ *         select (Handshake.msg_type) {
+ *             case client_hello:
+ *                 PskIdentity identities<6..2^16-1>;
+ *                 PskBinderEntry binders<33..2^16-1>;
+ *
+ *             case server_hello:
+ *                 uint16 selected_identity;
+ *         };
+ *
+ *     } PreSharedKeyExtension;
+
+ * Presently the only way to get a PSK is by resumption, so this is
+ * really a ticket label and there will be at most one.
+ */
+PRInt32
+tls13_ClientSendPreSharedKeyXtn(const sslSocket *ss, TLSExtensionData *xtnData,
+                                PRBool append,
+                                PRUint32 maxBytes)
+{
+    PRInt32 extension_length;
+    PRInt32 identities_length;
+    PRInt32 binders_length;
+    NewSessionTicket *session_ticket;
+
+    /* We only set statelessResume on the client in TLS 1.3 code. */
+    if (!ss->statelessResume)
+        return 0;
+
+    PORT_Assert(ss->vrange.max >= SSL_LIBRARY_VERSION_TLS_1_3);
+
+    /* The length computations are simplified by the fact that there
+     * is just one ticket at most. */
+    session_ticket = &ss->sec.ci.sid->u.ssl3.locked.sessionTicket;
+    identities_length =
+        2 +                              /* vector length */
+        2 + session_ticket->ticket.len + /* identity length + ticket len */
+        4;                               /* obfuscated_ticket_age */
+    binders_length =
+        2 + /* vector length */
+        1 + tls13_GetHashSizeForHash(
+                tls13_GetHashForCipherSuite(ss->sec.ci.sid->u.ssl3.cipherSuite));
+    extension_length =
+        2 + 2 + /* Type + length */
+        identities_length + binders_length;
+
+    if (maxBytes < (PRUint32)extension_length) {
+        PORT_Assert(0);
+        return 0;
+    }
+
+    if (append) {
+        SECStatus rv;
+        PRUint32 age;
+        unsigned int prefixLength;
+        PRUint8 binder[TLS13_MAX_FINISHED_SIZE];
+        unsigned int binderLen;
+
+        /* extension_type */
+        rv = ssl3_ExtAppendHandshakeNumber(ss, ssl_tls13_pre_shared_key_xtn, 2);
+        if (rv != SECSuccess)
+            goto loser;
+        rv = ssl3_ExtAppendHandshakeNumber(ss, extension_length - 4, 2);
+        if (rv != SECSuccess)
+            goto loser;
+        rv = ssl3_ExtAppendHandshakeNumber(ss, identities_length - 2, 2);
+        if (rv != SECSuccess)
+            goto loser;
+        rv = ssl3_ExtAppendHandshakeVariable(ss, session_ticket->ticket.data,
+                                             session_ticket->ticket.len, 2);
+        if (rv != SECSuccess)
+            goto loser;
+
+        /* Obfuscated age. */
+        age = ssl_Time() - session_ticket->received_timestamp;
+        age += session_ticket->ticket_age_add;
+        rv = ssl3_ExtAppendHandshakeNumber(ss, age, 4);
+        if (rv != SECSuccess)
+            goto loser;
+
+        /* Now the binders. */
+        prefixLength = ss->ssl3.hs.messages.len;
+        rv = tls13_ComputePskBinder(CONST_CAST(sslSocket, ss), PR_TRUE,
+                                    prefixLength, binder, &binderLen,
+                                    sizeof(binder));
+        if (rv != SECSuccess)
+            goto loser;
+        PORT_Assert(binderLen == tls13_GetHashSize(ss));
+        rv = ssl3_ExtAppendHandshakeNumber(ss, binders_length - 2, 2);
+        if (rv != SECSuccess)
+            goto loser;
+        rv = ssl3_ExtAppendHandshakeVariable(ss,
+                                             binder, binderLen, 1);
+        if (rv != SECSuccess)
+            goto loser;
+
+        PRINT_BUF(50, (ss, "Sending PreSharedKey value",
+                       session_ticket->ticket.data,
+                       session_ticket->ticket.len));
+
+        xtnData->sentSessionTicketInClientHello = PR_TRUE;
+        xtnData->advertised[xtnData->numAdvertised++] =
+            ssl_tls13_pre_shared_key_xtn;
+    }
+    return extension_length;
+
+loser:
+    xtnData->ticketTimestampVerified = PR_FALSE;
+    return -1;
+}
+
+/* Handle a TLS 1.3 PreSharedKey Extension. We only accept PSKs
+ * that contain session tickets. */
+SECStatus
+tls13_ServerHandlePreSharedKeyXtn(const sslSocket *ss, TLSExtensionData *xtnData, PRUint16 ex_type,
+                                  SECItem *data)
+{
+    SECItem inner;
+    SECStatus rv;
+    unsigned int numIdentities = 0;
+    unsigned int numBinders = 0;
+
+    SSL_TRC(3, ("%d: SSL3[%d]: handle pre_shared_key extension",
+                SSL_GETPID(), ss->fd));
+
+    /* If we are doing < TLS 1.3, then ignore this. */
+    if (ss->version < SSL_LIBRARY_VERSION_TLS_1_3) {
+        return SECSuccess;
+    }
+
+    /* Parse the identities list. */
+    rv = ssl3_ExtConsumeHandshakeVariable(ss,
+                                          &inner, 2, &data->data, &data->len);
+    if (rv != SECSuccess) {
+        return SECFailure;
+    }
+
+    while (inner.len) {
+        SECItem label;
+        PRUint32 utmp;
+
+        rv = ssl3_ExtConsumeHandshakeVariable(ss, &label, 2,
+                                              &inner.data, &inner.len);
+        if (rv != SECSuccess)
+            return rv;
+        if (!label.len) {
+            goto alert_loser;
+        }
+
+        /* Read and discard session ticket age. Bug 1295163 */
+        rv = ssl3_ExtConsumeHandshake(ss, &utmp, 4,
+                                      &inner.data, &inner.len);
+        if (rv != SECSuccess)
+            return rv;
+
+        if (!numIdentities) {
+            PRINT_BUF(50, (ss, "Handling PreSharedKey value",
+                           label.data, label.len));
+            rv = ssl3_ProcessSessionTicketCommon(
+                CONST_CAST(sslSocket, ss), &label);
+            /* This only happens if we have an internal error, not
+             * a malformed ticket. Bogus tickets just don't resume
+             * and return SECSuccess. */
+            if (rv != SECSuccess)
+                return SECFailure;
+        }
+        ++numIdentities;
+    }
+
+    xtnData->pskBinderPrefixLen = ss->ssl3.hs.messages.len - data->len;
+
+    /* Parse the binders list. */
+    rv = ssl3_ExtConsumeHandshakeVariable(ss,
+                                          &inner, 2, &data->data, &data->len);
+    if (rv != SECSuccess)
+        return SECFailure;
+    if (data->len) {
+        goto alert_loser;
+    }
+
+    while (inner.len) {
+        SECItem binder;
+        rv = ssl3_ExtConsumeHandshakeVariable(ss, &binder, 1,
+                                              &inner.data, &inner.len);
+        if (rv != SECSuccess)
+            return rv;
+        if (binder.len < 32) {
+            goto alert_loser;
+        }
+
+        if (!numBinders) {
+            xtnData->pskBinder = binder;
+        }
+        ++numBinders;
+    }
+
+    if (numBinders != numIdentities)
+        goto alert_loser;
+
+    /* Keep track of negotiated extensions. Note that this does not
+     * mean we are resuming. */
+    xtnData->negotiated[xtnData->numNegotiated++] = ex_type;
+
+    return SECSuccess;
+
+alert_loser:
+    ssl3_ExtSendAlert(ss, alert_fatal, illegal_parameter);
+    PORT_SetError(SSL_ERROR_MALFORMED_PRE_SHARED_KEY);
+    return SECFailure;
+}
+
+PRInt32
+tls13_ServerSendPreSharedKeyXtn(const sslSocket *ss, TLSExtensionData *xtnData,
+                                PRBool append,
+                                PRUint32 maxBytes)
+{
+    PRInt32 extension_length =
+        2 + 2 + 2; /* type + len + index */
+    SECStatus rv;
+
+    if (maxBytes < (PRUint32)extension_length) {
+        PORT_Assert(0);
+        return 0;
+    }
+
+    if (append) {
+        rv = ssl3_ExtAppendHandshakeNumber(ss, ssl_tls13_pre_shared_key_xtn, 2);
+        if (rv != SECSuccess)
+            return -1;
+
+        rv = ssl3_ExtAppendHandshakeNumber(ss, 2, 2);
+        if (rv != SECSuccess)
+            return -1;
+
+        /* We only process the first session ticket the client sends,
+         * so the index is always 0. */
+        rv = ssl3_ExtAppendHandshakeNumber(ss, 0, 2);
+        if (rv != SECSuccess)
+            return -1;
+    }
+
+    return extension_length;
+}
+
+/* Handle a TLS 1.3 PreSharedKey Extension. We only accept PSKs
+ * that contain session tickets. */
+SECStatus
+tls13_ClientHandlePreSharedKeyXtn(const sslSocket *ss, TLSExtensionData *xtnData, PRUint16 ex_type,
+                                  SECItem *data)
+{
+    PRInt32 index;
+
+    SSL_TRC(3, ("%d: SSL3[%d]: handle pre_shared_key extension",
+                SSL_GETPID(), ss->fd));
+
+    /* If we are doing < TLS 1.3, then ignore this. */
+    if (ss->version < SSL_LIBRARY_VERSION_TLS_1_3) {
+        return SECSuccess;
+    }
+
+    index = ssl3_ExtConsumeHandshakeNumber(ss, 2, &data->data, &data->len);
+    if (index < 0)
+        return SECFailure;
+
+    /* This should be the end of the extension. */
+    if (data->len) {
+        PORT_SetError(SSL_ERROR_MALFORMED_PRE_SHARED_KEY);
+        return SECFailure;
+    }
+
+    /* We only sent one PSK label so index must be equal to 0 */
+    if (index) {
+        PORT_SetError(SSL_ERROR_MALFORMED_PRE_SHARED_KEY);
+        return SECFailure;
+    }
+
+    /* Keep track of negotiated extensions. */
+    xtnData->negotiated[xtnData->numNegotiated++] = ex_type;
+
+    return SECSuccess;
+}
+
+/*
+ *  struct { } EarlyDataIndication;
+ */
+PRInt32
+tls13_ClientSendEarlyDataXtn(const sslSocket *ss, TLSExtensionData *xtnData,
+                             PRBool append,
+                             PRUint32 maxBytes)
+{
+    SECStatus rv;
+    PRInt32 extension_length;
+
+    if (!tls13_ClientAllow0Rtt(ss, ss->sec.ci.sid))
+        return 0;
+
+    /* type + length */
+    extension_length = 2 + 2;
+
+    if (maxBytes < (PRUint32)extension_length) {
+        PORT_Assert(0);
+        return 0;
+    }
+
+    if (append) {
+        rv = ssl3_ExtAppendHandshakeNumber(ss, ssl_tls13_early_data_xtn, 2);
+        if (rv != SECSuccess)
+            return -1;
+
+        rv = ssl3_ExtAppendHandshakeNumber(ss, 0, 2);
+        if (rv != SECSuccess)
+            return -1;
+    }
+
+    xtnData->advertised[xtnData->numAdvertised++] =
+        ssl_tls13_early_data_xtn;
+
+    return extension_length;
+}
+
+SECStatus
+tls13_ServerHandleEarlyDataXtn(const sslSocket *ss, TLSExtensionData *xtnData, PRUint16 ex_type,
+                               SECItem *data)
+{
+    SSL_TRC(3, ("%d: TLS13[%d]: handle early_data extension",
+                SSL_GETPID(), ss->fd));
+
+    /* If we are doing < TLS 1.3, then ignore this. */
+    if (ss->version < SSL_LIBRARY_VERSION_TLS_1_3) {
+        return SECSuccess;
+    }
+
+    if (data->len) {
+        PORT_SetError(SSL_ERROR_MALFORMED_EARLY_DATA);
+        return SECFailure;
+    }
+
+    xtnData->negotiated[xtnData->numNegotiated++] = ex_type;
+
+    return SECSuccess;
+}
+
+/* This is only registered if we are sending it. */
+PRInt32
+tls13_ServerSendEarlyDataXtn(const sslSocket *ss, TLSExtensionData *xtnData,
+                             PRBool append,
+                             PRUint32 maxBytes)
+{
+    SSL_TRC(3, ("%d: TLS13[%d]: send early_data extension",
+                SSL_GETPID(), ss->fd));
+
+    PORT_Assert(ss->ssl3.hs.zeroRttState == ssl_0rtt_accepted);
+    if (maxBytes < 4) {
+        PORT_Assert(0);
+        return 0;
+    }
+
+    if (append) {
+        SECStatus rv;
+
+        rv = ssl3_ExtAppendHandshakeNumber(ss, ssl_tls13_early_data_xtn, 2);
+        if (rv != SECSuccess)
+            return -1;
+
+        rv = ssl3_ExtAppendHandshakeNumber(ss, 0, 2);
+        if (rv != SECSuccess)
+            return -1;
+    }
+
+    return 4;
+}
+
+/* This will only be called if we also offered the extension. */
+SECStatus
+tls13_ClientHandleEarlyDataXtn(const sslSocket *ss, TLSExtensionData *xtnData, PRUint16 ex_type,
+                               SECItem *data)
+{
+    SSL_TRC(3, ("%d: TLS13[%d]: handle early_data extension",
+                SSL_GETPID(), ss->fd));
+
+    /* If we are doing < TLS 1.3, then ignore this. */
+    if (ss->version < SSL_LIBRARY_VERSION_TLS_1_3) {
+        PORT_SetError(SSL_ERROR_EXTENSION_DISALLOWED_FOR_VERSION);
+        return SECFailure;
+    }
+
+    if (data->len) {
+        PORT_SetError(SSL_ERROR_MALFORMED_EARLY_DATA);
+        return SECFailure;
+    }
+
+    /* Keep track of negotiated extensions. */
+    xtnData->negotiated[xtnData->numNegotiated++] = ex_type;
+
+    return SECSuccess;
+}
+
+SECStatus
+tls13_ClientHandleTicketEarlyDataInfoXtn(const sslSocket *ss, TLSExtensionData *xtnData, PRUint16 ex_type,
+                                         SECItem *data)
+{
+    PRUint32 utmp;
+    SECStatus rv;
+
+    SSL_TRC(3, ("%d: TLS13[%d]: handle early_data_info extension",
+                SSL_GETPID(), ss->fd));
+
+    /* If we are doing < TLS 1.3, then ignore this. */
+    if (ss->version < SSL_LIBRARY_VERSION_TLS_1_3) {
+        PORT_SetError(SSL_ERROR_EXTENSION_DISALLOWED_FOR_VERSION);
+        return SECFailure;
+    }
+
+    rv = ssl3_ExtConsumeHandshake(ss, &utmp, sizeof(utmp),
+                                  &data->data, &data->len);
+    if (rv != SECSuccess) {
+        PORT_SetError(SSL_ERROR_RX_MALFORMED_NEW_SESSION_TICKET);
+        return SECFailure;
+    }
+    if (data->len) {
+        PORT_SetError(SSL_ERROR_RX_MALFORMED_NEW_SESSION_TICKET);
+        return SECFailure;
+    }
+
+    xtnData->max_early_data_size = PR_ntohl(utmp);
+
+    return SECSuccess;
+}
+
+/*
+ *     struct {
+ *          ProtocolVersion versions<2..254>;
+ *     } SupportedVersions;
+ */
+PRInt32
+tls13_ClientSendSupportedVersionsXtn(const sslSocket *ss, TLSExtensionData *xtnData, PRBool append,
+                                     PRUint32 maxBytes)
+{
+    PRInt32 extensions_len;
+    PRUint16 version;
+    SECStatus rv;
+
+    if (ss->vrange.max < SSL_LIBRARY_VERSION_TLS_1_3) {
+        return 0;
+    }
+
+    SSL_TRC(3, ("%d: TLS13[%d]: send supported_versions extension",
+                SSL_GETPID(), ss->fd));
+
+    /* Extension type, extension len fiels, vector len field,
+     * length of the values. */
+    extensions_len = 2 + 2 + 1 +
+                     2 * (ss->vrange.max - ss->vrange.min + 1);
+
+    if (maxBytes < (PRUint32)extensions_len) {
+        PORT_Assert(0);
+        return 0;
+    }
+
+    if (append) {
+        rv = ssl3_ExtAppendHandshakeNumber(ss, ssl_tls13_supported_versions_xtn, 2);
+        if (rv != SECSuccess)
+            return -1;
+
+        rv = ssl3_ExtAppendHandshakeNumber(ss, extensions_len - 4, 2);
+        if (rv != SECSuccess)
+            return -1;
+
+        rv = ssl3_ExtAppendHandshakeNumber(ss, extensions_len - 5, 1);
+        if (rv != SECSuccess)
+            return -1;
+
+        for (version = ss->vrange.max; version >= ss->vrange.min; --version) {
+            rv = ssl3_ExtAppendHandshakeNumber(
+                ss, tls13_EncodeDraftVersion(version), 2);
+            if (rv != SECSuccess)
+                return -1;
+        }
+    }
+
+    return extensions_len;
+}
+
+/*
+ *    struct {
+ *        opaque cookie<1..2^16-1>;
+ *    } Cookie;
+ */
+SECStatus
+tls13_ClientHandleHrrCookie(const sslSocket *ss, TLSExtensionData *xtnData, PRUint16 ex_type, SECItem *data)
+{
+    SECStatus rv;
+
+    SSL_TRC(3, ("%d: TLS13[%d]: handle cookie extension",
+                SSL_GETPID(), ss->fd));
+
+    PORT_Assert(ss->vrange.max >= SSL_LIBRARY_VERSION_TLS_1_3);
+
+    /* IMPORTANT: this is only valid while the HelloRetryRequest is still valid. */
+    rv = ssl3_ExtConsumeHandshakeVariable(
+        ss, &CONST_CAST(sslSocket, ss)->ssl3.hs.cookie, 2,
+        &data->data, &data->len);
+    if (rv != SECSuccess) {
+        PORT_SetError(SSL_ERROR_RX_MALFORMED_HELLO_RETRY_REQUEST);
+        return SECFailure;
+    }
+    if (!ss->ssl3.hs.cookie.len || data->len) {
+        ssl3_ExtSendAlert(ss, alert_fatal, decode_error);
+        PORT_SetError(SSL_ERROR_RX_MALFORMED_HELLO_RETRY_REQUEST);
+        return SECFailure;
+    }
+
+    return SECSuccess;
+}
+
+PRInt32
+tls13_ClientSendHrrCookieXtn(const sslSocket *ss, TLSExtensionData *xtnData, PRBool append, PRUint32 maxBytes)
+{
+    PRInt32 extension_len;
+
+    if (ss->vrange.max < SSL_LIBRARY_VERSION_TLS_1_3 ||
+        !ss->ssl3.hs.cookie.len) {
+        return 0;
+    }
+
+    SSL_TRC(3, ("%d: TLS13[%d]: send cookie extension", SSL_GETPID(), ss->fd));
+
+    /* Extension type, length, cookie length, cookie value. */
+    extension_len = 2 + 2 + 2 + ss->ssl3.hs.cookie.len;
+
+    if (maxBytes < (PRUint32)extension_len) {
+        PORT_Assert(0);
+        return 0;
+    }
+
+    if (append) {
+        SECStatus rv = ssl3_ExtAppendHandshakeNumber(ss, ssl_tls13_cookie_xtn, 2);
+        if (rv != SECSuccess)
+            return -1;
+
+        rv = ssl3_ExtAppendHandshakeNumber(ss, extension_len - 4, 2);
+        if (rv != SECSuccess)
+            return -1;
+
+        rv = ssl3_ExtAppendHandshakeVariable(ss, ss->ssl3.hs.cookie.data,
+                                             ss->ssl3.hs.cookie.len, 2);
+        if (rv != SECSuccess)
+            return -1;
+    }
+    return extension_len;
+}
+
+/*
+ *     enum { psk_ke(0), psk_dhe_ke(1), (255) } PskKeyExchangeMode;
+ *
+ *     struct {
+ *         PskKeyExchangeMode ke_modes<1..255>;
+ *     } PskKeyExchangeModes;
+ */
+PRInt32
+tls13_ClientSendPskKeyExchangeModesXtn(const sslSocket *ss,
+                                       TLSExtensionData *xtnData,
+                                       PRBool append, PRUint32 maxBytes)
+{
+    static const PRUint8 ke_modes[] = { tls13_psk_dh_ke };
+    static const unsigned long ke_modes_len = sizeof(ke_modes);
+    PRInt32 extension_len;
+
+    if (ss->vrange.max < SSL_LIBRARY_VERSION_TLS_1_3 ||
+        ss->opt.noCache) {
+        return 0;
+    }
+
+    extension_len =
+        2 + 2 +           /* Type + length */
+        1 + ke_modes_len; /* key exchange modes vector */
+
+    SSL_TRC(3, ("%d: TLS13[%d]: send psk key exchange modes extension",
+                SSL_GETPID(), ss->fd));
+
+    if (maxBytes < (PRUint32)extension_len) {
+        PORT_Assert(0);
+        return 0;
+    }
+
+    if (append) {
+        SECStatus rv = ssl3_ExtAppendHandshakeNumber(
+            ss, ssl_tls13_psk_key_exchange_modes_xtn, 2);
+        if (rv != SECSuccess)
+            return -1;
+
+        rv = ssl3_ExtAppendHandshakeNumber(ss, extension_len - 4, 2);
+        if (rv != SECSuccess)
+            return -1;
+
+        rv = ssl3_ExtAppendHandshakeVariable(
+            ss, ke_modes, ke_modes_len, 1);
+        if (rv != SECSuccess)
+            return -1;
+    }
+    return extension_len;
+}
+
+SECStatus
+tls13_ServerHandlePskKeyExchangeModesXtn(const sslSocket *ss,
+                                         TLSExtensionData *xtnData,
+                                         PRUint16 ex_type, SECItem *data)
+{
+    SECStatus rv;
+
+    /* If we are doing < TLS 1.3, then ignore this. */
+    if (ss->version < SSL_LIBRARY_VERSION_TLS_1_3) {
+        return SECSuccess;
+    }
+
+    SSL_TRC(3, ("%d: TLS13[%d]: handle PSK key exchange modes extension",
+                SSL_GETPID(), ss->fd));
+
+    /* IMPORTANT: We aren't copying these values, just setting pointers.
+     * They will only be valid as long as the ClientHello is in memory. */
+    rv = ssl3_ExtConsumeHandshakeVariable(ss,
+                                          &xtnData->psk_ke_modes, 1,
+                                          &data->data, &data->len);
+    if (rv != SECSuccess)
+        return rv;
+    if (!xtnData->psk_ke_modes.len || data->len) {
+        PORT_SetError(SSL_ERROR_MALFORMED_PSK_KEY_EXCHANGE_MODES);
+        return SECFailure;
+    }
+
+    /* Keep track of negotiated extensions. */
+    xtnData->negotiated[xtnData->numNegotiated++] = ex_type;
+
+    return SECSuccess;
+}
+
+PRInt32
+tls13_SendShortHeaderXtn(const sslSocket *ss,
+                         TLSExtensionData *xtnData,
+                         PRBool append, PRUint32 maxBytes)
+{
+    PRUint32 extension_len = 2 + 2; /* Type + length (0). */
+
+    if (!ss->opt.enableShortHeaders) {
+        return 0;
+    }
+
+    /* Presently this is incompatible with 0-RTT. We will fix if
+     * it becomes more than an experiment. */
+    if (ss->opt.enable0RttData) {
+        return 0;
+    }
+
+    if (IS_DTLS(ss)) {
+        return 0;
+    }
+
+    SSL_TRC(3, ("%d: TLS13[%d]: send short_header extension",
+                SSL_GETPID(), ss->fd));
+
+    if (maxBytes < extension_len) {
+        PORT_Assert(0);
+        return 0;
+    }
+
+    if (append) {
+        SECStatus rv;
+
+        rv = ssl3_ExtAppendHandshakeNumber(ss, ssl_tls13_short_header_xtn, 2);
+        if (rv != SECSuccess)
+            return -1;
+
+        rv = ssl3_ExtAppendHandshakeNumber(ss, 0, 2);
+        if (rv != SECSuccess)
+            return -1;
+
+        xtnData->advertised[xtnData->numAdvertised++] =
+            ssl_tls13_short_header_xtn;
+    }
+
+    return extension_len;
+}
+
+SECStatus
+tls13_HandleShortHeaderXtn(
+    const sslSocket *ss, TLSExtensionData *xtnData, PRUint16 ex_type,
+    SECItem *data)
+{
+    SSL_TRC(3, ("%d: TLS13[%d]: handle early_data extension",
+                SSL_GETPID(), ss->fd));
+
+    /* If we are doing < TLS 1.3, then ignore this. */
+    if (ss->version < SSL_LIBRARY_VERSION_TLS_1_3) {
+        return SECSuccess;
+    }
+
+    /* Presently this is incompatible with 0-RTT. We will fix if
+     * it becomes more than an experiment. */
+    if (ss->opt.enable0RttData) {
+        return SECSuccess;
+    }
+
+    if (IS_DTLS(ss)) {
+        PORT_SetError(SSL_ERROR_EXTENSION_DISALLOWED_FOR_VERSION);
+        return SECFailure;
+    }
+
+    if (data->len) {
+        PORT_SetError(SSL_ERROR_RX_MALFORMED_HANDSHAKE);
+        return SECFailure;
+    }
+
+    if (!ss->opt.enableShortHeaders) {
+        /* Ignore. */
+        return SECSuccess;
+    }
+
+    /* Keep track of negotiated extensions. */
+    xtnData->negotiated[xtnData->numNegotiated++] = ex_type;
+
+    if (ss->sec.isServer) {
+        SECStatus rv;
+
+        rv = ssl3_RegisterExtensionSender(ss, xtnData,
+                                          ssl_tls13_short_header_xtn,
+                                          tls13_SendShortHeaderXtn);
+        if (rv != SECSuccess) {
+            return SECFailure;
+        }
+    }
+
+    return SECSuccess;
+}