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/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is PRIVATE to SSL.
*
* 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/. */
#ifndef __tls13ech_h_
#define __tls13ech_h_
#include "pk11hpke.h"
/* draft-09, supporting shared-mode and split-mode as a backend server only.
* Notes on the implementation status:
* - Padding (https://tools.ietf.org/html/draft-ietf-tls-esni-08#section-6.2),
* is not implemented (see bug 1677181).
* - When multiple ECHConfigs are provided by the server, the first compatible
* config is selected by the client. Ciphersuite choices are limited and only
* the AEAD may vary (AES-128-GCM or ChaCha20Poly1305).
* - Some of the buffering (construction/compression/decompression) could likely
* be optimized, but the spec is still evolving so that work is deferred.
*/
#define TLS13_ECH_VERSION 0xfe0d
#define TLS13_ECH_SIGNAL_LEN 8
#define TLS13_ECH_AEAD_TAG_LEN 16
static const char kHpkeInfoEch[] = "tls ech";
static const char hHkdfInfoEchConfigID[] = "tls ech config id";
static const char kHkdfInfoEchConfirm[] = "ech accept confirmation";
static const char kHkdfInfoEchHrrConfirm[] = "hrr ech accept confirmation";
typedef enum {
ech_xtn_type_outer = 0,
ech_xtn_type_inner = 1,
} EchXtnType;
struct sslEchConfigContentsStr {
PRUint8 configId;
HpkeKemId kemId;
SECItem publicKey; /* NULL on server. Use the keypair in sslEchConfig instead. */
HpkeKdfId kdfId;
HpkeAeadId aeadId;
SECItem suites; /* One or more HpkeCipherSuites. The selected s
* suite is placed in kdfId and aeadId. */
PRUint8 maxNameLen;
char *publicName;
/* No supported extensions. */
};
/* ECH Information needed by a server to process a second CH after a
* HelloRetryRequest is sent. This data is stored in the cookie.
*/
struct sslEchCookieDataStr {
PRBool previouslyOffered;
PRUint8 configId;
HpkeKdfId kdfId;
HpkeAeadId aeadId;
HpkeContext *hpkeCtx;
PRUint8 signal[TLS13_ECH_SIGNAL_LEN];
};
struct sslEchConfigStr {
PRCList link;
SECItem raw;
PRUint16 version;
sslEchConfigContents contents;
};
struct sslEchXtnStateStr {
SECItem innerCh; /* Server: ClientECH.payload */
SECItem senderPubKey; /* Server: ClientECH.enc */
PRUint8 configId; /* Server: ClientECH.config_id */
HpkeKdfId kdfId; /* Server: ClientECH.cipher_suite.kdf */
HpkeAeadId aeadId; /* Server: ClientECH.cipher_suite.aead */
SECItem retryConfigs; /* Client: ServerECH.retry_configs*/
PRBool retryConfigsValid; /* Client: Extraction of retry_configss is allowed.
* This is set once the handshake completes (having
* verified to the ECHConfig public name). */
PRUint8 *hrrConfirmation; /* Client/Server: HRR Confirmation Location */
PRBool receivedInnerXtn; /* Server: Handled ECH Xtn with Inner Enum */
PRUint8 *payloadStart; /* Server: Start of ECH Payload*/
};
SEC_BEGIN_PROTOS
SECStatus SSLExp_EncodeEchConfigId(PRUint8 configId, const char *publicName, unsigned int maxNameLen,
HpkeKemId kemId, const SECKEYPublicKey *pubKey,
const HpkeSymmetricSuite *hpkeSuites, unsigned int hpkeSuiteCount,
PRUint8 *out, unsigned int *outlen, unsigned int maxlen);
SECStatus SSLExp_GetEchRetryConfigs(PRFileDesc *fd, SECItem *retryConfigs);
SECStatus SSLExp_SetClientEchConfigs(PRFileDesc *fd, const PRUint8 *echConfigs,
unsigned int echConfigsLen);
SECStatus SSLExp_SetServerEchConfigs(PRFileDesc *fd,
const SECKEYPublicKey *pubKey, const SECKEYPrivateKey *privKey,
const PRUint8 *echConfigs, unsigned int numEchConfigs);
SECStatus SSLExp_RemoveEchConfigs(PRFileDesc *fd);
SEC_END_PROTOS
SECStatus tls13_ClientSetupEch(sslSocket *ss, sslClientHelloType type);
SECStatus tls13_ConstructClientHelloWithEch(sslSocket *ss, const sslSessionID *sid,
PRBool freshSid, sslBuffer *chOuterBuf,
sslBuffer *chInnerXtnsBuf);
SECStatus tls13_CopyEchConfigs(PRCList *oconfigs, PRCList *configs);
SECStatus tls13_DecodeEchConfigs(const SECItem *data, PRCList *configs);
void tls13_DestroyEchConfigs(PRCList *list);
void tls13_DestroyEchXtnState(sslEchXtnState *state);
SECStatus tls13_GetMatchingEchConfig(const sslSocket *ss, HpkeKdfId kdf, HpkeAeadId aead,
const SECItem *configId, sslEchConfig **cfg);
SECStatus tls13_MaybeHandleEch(sslSocket *ss, const PRUint8 *msg, PRUint32 msgLen, SECItem *sidBytes,
SECItem *comps, SECItem *cookieBytes, SECItem *suites, SECItem **echInner);
SECStatus tls13_MaybeHandleEchSignal(sslSocket *ss, const PRUint8 *savedMsg, PRUint32 savedLength, PRBool isHrr);
SECStatus tls13_MaybeAcceptEch(sslSocket *ss, const SECItem *sidBytes, const PRUint8 *chOuter,
unsigned int chOuterLen, SECItem **chInner);
SECStatus tls13_MaybeGreaseEch(sslSocket *ss, const sslBuffer *preamble, sslBuffer *buf);
SECStatus tls13_WriteServerEchSignal(sslSocket *ss, PRUint8 *sh, unsigned int shLen);
SECStatus tls13_WriteServerEchHrrSignal(sslSocket *ss, PRUint8 *sh, unsigned int shLen);
SECStatus tls13_DeriveEchSecret(const sslSocket *ss, PK11SymKey **output);
SECStatus tls13_ComputeEchSignal(sslSocket *ss, PRBool isHrr, const PRUint8 *sh, unsigned int shLen, PRUint8 *out);
PRBool tls13_IsIp(const PRUint8 *str, unsigned int len);
PRBool tls13_IsLDH(const PRUint8 *str, unsigned int len);
#endif
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