/src/gnutls/lib/gnutls_int.h

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/*
 * Copyright (C) 2000-2016 Free Software Foundation, Inc.
 * Copyright (C) 2015-2018 Red Hat, Inc.
 *
 * Author: Nikos Mavrogiannopoulos
 *
 * This file is part of GnuTLS.
 *
 * The GnuTLS is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>
 *
 */

#ifndef GNUTLS_LIB_GNUTLS_INT_H
#define GNUTLS_LIB_GNUTLS_INT_H

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stddef.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include <limits.h>
#include <stdint.h>
#include <stdbool.h>
#include <assert.h>

#ifdef NO_SSIZE_T
#define HAVE_SSIZE_T
typedef int ssize_t;
#endif

#include <sys/types.h>
#include <unistd.h>
#include <sys/stat.h>
#if HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#elif HAVE_WS2TCPIP_H
#include <ws2tcpip.h>
#endif
#include <time.h>

#include "attribute.h"

#define ENABLE_ALIGN16

#ifdef __clang_major
#define _GNUTLS_CLANG_VERSION \
  (__clang_major__ * 10000 + __clang_minor__ * 100 + __clang_patchlevel__)
#else
#define _GNUTLS_CLANG_VERSION 0
#endif

/* clang also defines __GNUC__. It promotes a GCC version of 4.2.1. */
#ifdef __GNUC__
#define _GNUTLS_GCC_VERSION \
  (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
#endif

#if _GNUTLS_GCC_VERSION >= 30100
#define likely(x) __builtin_expect((x), 1)
#define unlikely(x) __builtin_expect((x), 0)
#else
#define likely
#define unlikely
#endif

#include <gnutls/gnutls.h>
#include <gnutls/dtls.h>
#include <gnutls/abstract.h>
#include <gnutls/socket.h>
#include "system.h"

/* in case we compile with system headers taking priority, we
 * make sure that some new attributes are still available.
 */
#ifndef __GNUTLS_CONST__
#define __GNUTLS_CONST__
#endif

/* The size of a handshake message should not
 * be larger than this value.
 */
#define MAX_HANDSHAKE_PACKET_SIZE 128 * 1024

#define GNUTLS_DEF_SESSION_ID_SIZE 32

/* The maximum digest size of hash algorithms.
 */
#define MAX_FILENAME 512
#define MAX_HASH_SIZE 64

#define MAX_MAC_KEY_SIZE 64

#define MAX_CIPHER_BLOCK_SIZE 64 /* CHACHA20 */
#define MAX_CIPHER_KEY_SIZE 32

#define MAX_CIPHER_IV_SIZE 16

/* Maximum size of 2^16-1 has been chosen so that usernames can hold
 * PSK identities as defined in RFC 4279 section 2 and RFC 8446 section 4.2.11
 */
#define MAX_USERNAME_SIZE 65535
#define MAX_SERVER_NAME_SIZE 256

#define AEAD_EXPLICIT_DATA_SIZE 8
#define AEAD_IMPLICIT_DATA_SIZE 4

#define GNUTLS_MASTER_SIZE 48
#define GNUTLS_RANDOM_SIZE 32

/* Under TLS1.3 a hello retry request is sent as server hello */
#define REAL_HSK_TYPE(t)                               \
  ((t) == GNUTLS_HANDSHAKE_HELLO_RETRY_REQUEST ? \
     GNUTLS_HANDSHAKE_SERVER_HELLO :       \
     t)

/* DTLS */
#define DTLS_RETRANS_TIMEOUT 1000

/* TLS Extensions */
/* we can receive up to MAX_EXT_TYPES extensions.
 */
#define MAX_EXT_TYPES 64

/* TLS-internal extension (will be parsed after a ciphersuite is selected).
 * This amends the gnutls_ext_parse_type_t. Not exported yet to allow more refining
 * prior to finalizing an API. */
#define _GNUTLS_EXT_TLS_POST_CS 177

/* expire time for resuming sessions */
#define DEFAULT_EXPIRE_TIME 21600
#define STEK_ROTATION_PERIOD_PRODUCT 3
#define DEFAULT_HANDSHAKE_TIMEOUT_MS 40 * 1000

/* The EC group to be used when the extension
 * supported groups/curves is not present */
#define DEFAULT_EC_GROUP GNUTLS_GROUP_SECP256R1

typedef enum transport_t {
  GNUTLS_STREAM,
  GNUTLS_DGRAM
} transport_t;

/* The TLS 1.3 stage of handshake */
typedef enum hs_stage_t {
  STAGE_HS,
  STAGE_APP,
  STAGE_UPD_OURS,
  STAGE_UPD_PEERS,
  STAGE_EARLY
} hs_stage_t;

typedef enum record_send_state_t {
  RECORD_SEND_NORMAL = 0,
  RECORD_SEND_CORKED, /* corked and transition to NORMAL afterwards */
  RECORD_SEND_CORKED_TO_KU, /* corked but must transition to RECORD_SEND_KEY_UPDATE_1 */
  RECORD_SEND_KEY_UPDATE_1,
  RECORD_SEND_KEY_UPDATE_2,
  RECORD_SEND_KEY_UPDATE_3
} record_send_state_t;

/* The mode check occurs a lot throughout GnuTLS and can be replaced by
 * the following shorter macro. Also easier to update one macro
 * in the future when the internal structure changes than all the conditionals
 * itself.
 */
#define IS_SERVER(session) \
  (session->security_parameters.entity == GNUTLS_SERVER)

/* To check whether we have a DTLS session */
#define IS_DTLS(session) (session->internals.transport == GNUTLS_DGRAM)

/* To check whether we have a KTLS enabled */
#define IS_KTLS_ENABLED(session, interface) \
  (session->internals.ktls_enabled & interface)

/* the maximum size of encrypted packets */
#define DEFAULT_MAX_RECORD_SIZE 16384
#define DEFAULT_MAX_EARLY_DATA_SIZE 16384
#define TLS_RECORD_HEADER_SIZE 5
#define DTLS_RECORD_HEADER_SIZE (TLS_RECORD_HEADER_SIZE + 8)
#define RECORD_HEADER_SIZE(session) \
  (IS_DTLS(session) ? DTLS_RECORD_HEADER_SIZE : TLS_RECORD_HEADER_SIZE)
#define MAX_RECORD_HEADER_SIZE DTLS_RECORD_HEADER_SIZE

#define MIN_RECORD_SIZE 512
#define MIN_RECORD_SIZE_SMALL 64

/* The following macro is used to calculate the overhead when sending.
 * when receiving we use a different way as there are implementations that
 * store more data than allowed.
 */
#define MAX_RECORD_SEND_OVERHEAD(session) \
  (MAX_CIPHER_BLOCK_SIZE /*iv*/ + MAX_PAD_SIZE + MAX_HASH_SIZE /*MAC*/)
#define MAX_PAD_SIZE 255
#define EXTRA_COMP_SIZE 2048

#define TLS_HANDSHAKE_HEADER_SIZE 4
#define DTLS_HANDSHAKE_HEADER_SIZE (TLS_HANDSHAKE_HEADER_SIZE + 8)
#define HANDSHAKE_HEADER_SIZE(session)                   \
  (IS_DTLS(session) ? DTLS_HANDSHAKE_HEADER_SIZE : \
          TLS_HANDSHAKE_HEADER_SIZE)
#define MAX_HANDSHAKE_HEADER_SIZE DTLS_HANDSHAKE_HEADER_SIZE

/* Maximum seed size for provable parameters */
#define MAX_PVP_SEED_SIZE 256

/* This is the maximum handshake message size we send without
   fragmentation. This currently ignores record layer overhead. */
#define DTLS_DEFAULT_MTU 1200

/* the maximum size of the DTLS cookie */
#define DTLS_MAX_COOKIE_SIZE 32

/* The maximum number of HELLO_VERIFY_REQUEST messages the client
   processes before aborting. */
#define MAX_HANDSHAKE_HELLO_VERIFY_REQUESTS 5

#define MAX_PK_PARAM_SIZE 2048

/* Defaults for verification functions.
 *
 * update many_icas in tests/test-chains.h when increasing
 * DEFAULT_MAX_VERIFY_DEPTH.
 */
#define DEFAULT_MAX_VERIFY_DEPTH 16
#define DEFAULT_MAX_VERIFY_BITS (MAX_PK_PARAM_SIZE * 8)
#define MAX_VERIFY_DEPTH 4096

#include "mem.h"

#define MEMSUB(x, y) ((ssize_t)((ptrdiff_t)x - (ptrdiff_t)y))

#define DECR_LEN(len, x) \
  DECR_LENGTH_RET(len, x, GNUTLS_E_UNEXPECTED_PACKET_LENGTH)
#define DECR_LEN_FINAL(len, x)                                      \
  do {                                                        \
    if (len != x)                                       \
      return gnutls_assert_val(                   \
        GNUTLS_E_UNEXPECTED_PACKET_LENGTH); \
    else                                                \
      len = 0;                                    \
  } while (0)
#define DECR_LENGTH_RET(len, x, RET) DECR_LENGTH_COM(len, x, return RET)
#define DECR_LENGTH_COM(len, x, COM)     \
  do {                             \
    if (len < x) {           \
      gnutls_assert(); \
      COM;             \
    } else                   \
      len -= x;        \
  } while (0)

#define GNUTLS_POINTER_TO_INT(_) ((int)GNUTLS_POINTER_TO_INT_CAST(_))
#define GNUTLS_INT_TO_POINTER(_) ((void *)GNUTLS_POINTER_TO_INT_CAST(_))

#define GNUTLS_KX_INVALID (-1)

#include "mpi.h"

typedef enum handshake_state_t {
  STATE0 = 0,
  STATE1,
  STATE2,
  STATE3,
  STATE4,
  STATE5,
  STATE6,
  STATE7,
  STATE8,
  STATE9,
  STATE10,
  STATE11,
  STATE12,
  STATE13,
  STATE14,
  STATE15,
  STATE16,
  STATE17,
  STATE18,
  STATE19,
  STATE20 = 20,
  STATE21,
  STATE22,
  STATE30 = 30,
  STATE31,
  STATE40 = 40,
  STATE41,
  STATE50 = 50,
  STATE90 = 90,
  STATE91,
  STATE92,
  STATE93,
  STATE94,
  STATE99 = 99,
  STATE100 = 100,
  STATE101,
  STATE102,
  STATE103,
  STATE104,
  STATE105,
  STATE106,
  STATE107,
  STATE108,
  STATE109,
  STATE110,
  STATE111,
  STATE112,
  STATE113,
  STATE114,
  STATE115,
  STATE150 /* key update */
} handshake_state_t;

typedef enum bye_state_t {
  BYE_STATE0 = 0,
  BYE_STATE1,
  BYE_STATE2
} bye_state_t;

typedef enum send_ticket_state_t {
  TICKET_STATE0 = 0,
  TICKET_STATE1
} send_ticket_state_t;

typedef enum reauth_state_t {
  REAUTH_STATE0 = 0,
  REAUTH_STATE1,
  REAUTH_STATE2,
  REAUTH_STATE3,
  REAUTH_STATE4,
  REAUTH_STATE5
} reauth_state_t;

#define TICKET_STATE session->internals.ticket_state
#define BYE_STATE session->internals.bye_state
#define REAUTH_STATE session->internals.reauth_state

typedef enum heartbeat_state_t {
  SHB_SEND1 = 0,
  SHB_SEND2,
  SHB_RECV
} heartbeat_state_t;

typedef enum recv_state_t {
  RECV_STATE_0 = 0,
  RECV_STATE_DTLS_RETRANSMIT,
  /* client-side false start state */
  RECV_STATE_FALSE_START_HANDLING, /* we are calling gnutls_handshake() within record_recv() */
  RECV_STATE_FALSE_START, /* gnutls_record_recv() should complete the handshake */
  /* async handshake msg state */
  RECV_STATE_ASYNC_HANDSHAKE, /* an incomplete async handshake message was seen */
  /* server-side early start under TLS1.3; enabled when no client cert is received */
  RECV_STATE_EARLY_START_HANDLING, /* we are calling gnutls_handshake() within record_recv() */
  RECV_STATE_EARLY_START, /* gnutls_record_recv() should complete the handshake */
  RECV_STATE_REHANDSHAKE, /* gnutls_record_recv() should complete any incoming re-handshake requests */
  RECV_STATE_REAUTH /* gnutls_record_recv() should complete any incoming reauthentication requests */
} recv_state_t;

#include "str.h"

/* This is the maximum number of algorithms (ciphers or macs etc).
 * keep it synced with GNUTLS_MAX_ALGORITHM_NUM in gnutls.h
 */
#define MAX_ALGOS GNUTLS_MAX_ALGORITHM_NUM

/* IDs are allocated in a way that all values fit in 64-bit integer as (1<<val) */
typedef enum extensions_t {
  GNUTLS_EXTENSION_INVALID = 0xffff,
  GNUTLS_EXTENSION_STATUS_REQUEST = 0,
  GNUTLS_EXTENSION_CERT_TYPE,
  GNUTLS_EXTENSION_CLIENT_CERT_TYPE,
  GNUTLS_EXTENSION_SERVER_CERT_TYPE,
  GNUTLS_EXTENSION_SUPPORTED_GROUPS,
  GNUTLS_EXTENSION_SUPPORTED_EC_POINT_FORMATS,
  GNUTLS_EXTENSION_SRP,
  GNUTLS_EXTENSION_SIGNATURE_ALGORITHMS,
  GNUTLS_EXTENSION_SRTP,
  GNUTLS_EXTENSION_HEARTBEAT,
  GNUTLS_EXTENSION_ALPN,
  GNUTLS_EXTENSION_ETM,
  GNUTLS_EXTENSION_EXT_MASTER_SECRET,
  GNUTLS_EXTENSION_SESSION_TICKET,
  GNUTLS_EXTENSION_KEY_SHARE,
  GNUTLS_EXTENSION_SUPPORTED_VERSIONS,
  GNUTLS_EXTENSION_POST_HANDSHAKE,
  GNUTLS_EXTENSION_SAFE_RENEGOTIATION,
  GNUTLS_EXTENSION_SERVER_NAME,
  GNUTLS_EXTENSION_COOKIE,
  GNUTLS_EXTENSION_EARLY_DATA,
  GNUTLS_EXTENSION_PSK_KE_MODES,
  GNUTLS_EXTENSION_RECORD_SIZE_LIMIT,
  GNUTLS_EXTENSION_MAX_RECORD_SIZE,
  GNUTLS_EXTENSION_COMPRESS_CERTIFICATE,
  /*
   * pre_shared_key and dumbfw must always be the last extensions,
   * in that order */
  GNUTLS_EXTENSION_DUMBFW,
  GNUTLS_EXTENSION_PRE_SHARED_KEY,
  GNUTLS_EXTENSION_MAX /* not real extension - used for iterators */
} extensions_t;

#define GNUTLS_EXTENSION_MAX_VALUE 63
#define ext_track_t uint64_t

#include <verify.h>

verify(GNUTLS_EXTENSION_MAX < GNUTLS_EXTENSION_MAX_VALUE);
verify(GNUTLS_EXTENSION_MAX < MAX_EXT_TYPES);

/* we must provide at least 16 extensions for users to register;
 * increase GNUTLS_EXTENSION_MAX_VALUE, MAX_EXT_TYPES and used_exts
 * type if this fails
 */
verify(GNUTLS_EXTENSION_MAX_VALUE - GNUTLS_EXTENSION_MAX >= 16);

/* MAX_EXT_TYPES must fit in a single byte, to generate random
 * permutation at once.
 */
verify(MAX_EXT_TYPES <= UINT8_MAX);

/* The 'verify' symbol from <verify.h> is used extensively in the
 * code; undef it to avoid clash
 */
#undef verify

typedef enum {
  CIPHER_STREAM,
  CIPHER_BLOCK,
  CIPHER_AEAD
} cipher_type_t;

/* Record Protocol */
typedef enum content_type_t {
  GNUTLS_CHANGE_CIPHER_SPEC = 20,
  GNUTLS_ALERT,
  GNUTLS_HANDSHAKE,
  GNUTLS_APPLICATION_DATA,
  GNUTLS_HEARTBEAT
} content_type_t;

#define GNUTLS_PK_ANY (gnutls_pk_algorithm_t) - 1
#define GNUTLS_PK_NONE (gnutls_pk_algorithm_t) - 2

#define GNUTLS_PK_IS_RSA(pk)                                   \
  ((pk) == GNUTLS_PK_RSA || (pk) == GNUTLS_PK_RSA_PSS || \
   (pk) == GNUTLS_PK_RSA_OAEP)

/* Message buffers (mbuffers) structures */

/* this is actually the maximum number of distinct handshake
 * messages that can arrive in a single flight
 */
#define MAX_HANDSHAKE_MSGS 6
typedef struct {
  /* Handshake layer type and sequence of message */
  gnutls_handshake_description_t htype;

  /* The "real" type received; that is, it does not distinguish
   * HRR from server hello, while htype does */
  gnutls_handshake_description_t rtype;
  uint32_t length;

  /* valid in DTLS */
  uint16_t sequence;

  /* indicate whether that message is complete.
   * complete means start_offset == 0 and end_offset == length
   */
  uint32_t start_offset;
  uint32_t end_offset;

  uint8_t header[MAX_HANDSHAKE_HEADER_SIZE];
  int header_size;

  gnutls_buffer_st data;
} handshake_buffer_st;

typedef struct mbuffer_st {
  /* when used in mbuffer_head_st */
  struct mbuffer_st *next;
  struct mbuffer_st *prev;

  /* msg->size - mark = number of bytes left to process in this
     message. Mark should only be non-zero when this buffer is the
     head of the queue. */
  size_t mark;

  /* the data */
  gnutls_datum_t msg;
  size_t maximum_size;

  /* used during fill in, to separate header from data
   * body. */
  unsigned int uhead_mark;

  /* Filled in by record layer on recv:
   * type, record_sequence
   */

  /* record layer content type */
  content_type_t type;

  /* record layer sequence */
  uint64_t record_sequence;

  /* Filled in by handshake layer on send:
   * type, epoch, htype, handshake_sequence
   */

  /* Record layer epoch of message */
  uint16_t epoch;

  /* Handshake layer type and sequence of message */
  gnutls_handshake_description_t htype;
  uint16_t handshake_sequence;
} mbuffer_st;

typedef struct mbuffer_head_st {
  mbuffer_st *head;
  mbuffer_st *tail;

  unsigned int length;
  size_t byte_length;
} mbuffer_head_st;

/* Store & Retrieve functions defines:
 */

typedef struct auth_cred_st {
  gnutls_credentials_type_t algorithm;

  /* the type of credentials depends on algorithm
   */
  void *credentials;
  struct auth_cred_st *next;
} auth_cred_st;

/* session ticket definitions */
#define TICKET_MASTER_KEY_SIZE \
  (TICKET_KEY_NAME_SIZE + TICKET_CIPHER_KEY_SIZE + TICKET_MAC_SECRET_SIZE)
#define TICKET_KEY_NAME_SIZE 16
#define TICKET_CIPHER_KEY_SIZE 32
#define TICKET_MAC_SECRET_SIZE 16

/* These are restricted by TICKET_CIPHER_KEY_SIZE and TICKET_MAC_SECRET_SIZE */
#define TICKET_CIPHER GNUTLS_CIPHER_AES_256_CBC
#define TICKET_IV_SIZE 16
#define TICKET_BLOCK_SIZE 16

#define TICKET_MAC_ALGO GNUTLS_MAC_SHA1
#define TICKET_MAC_SIZE 20 /* HMAC-SHA1 */

struct ticket_st {
  uint8_t key_name[TICKET_KEY_NAME_SIZE];
  uint8_t IV[TICKET_IV_SIZE];
  uint8_t *encrypted_state;
  uint16_t encrypted_state_len;
  uint8_t mac[TICKET_MAC_SIZE];
};

struct binder_data_st {
  const struct mac_entry_st *prf; /* non-null if this struct is set */
  gnutls_datum_t psk;

  /* 0-based index of the selected PSK.
   * This only applies if the HSK_PSK_SELECTED flag is set in internals.hsk_flags,
   * which signals a PSK has indeed been selected. */
  uint8_t idx;
  uint8_t resumption; /* whether it is a resumption binder */
};

typedef void (*gnutls_stek_rotation_callback_t)(const gnutls_datum_t *prev_key,
            const gnutls_datum_t *new_key,
            uint64_t t);

struct gnutls_key_st {
  struct { /* These are kept outside the TLS1.3 union as they are
         * negotiated via extension, even before protocol is negotiated */
    gnutls_pk_params_st ecdh_params;
    gnutls_pk_params_st ecdhx_params;
    gnutls_pk_params_st dh_params;
    gnutls_pk_params_st kem_params;
  } kshare;

  /* The union contents depend on the negotiated protocol.
   * It should not contain any values which are allocated
   * prior to protocol negotiation, as it would be impossible
   * to deinitialize.
   */
  union {
    struct {
      /* the current (depending on state) secret, can be
       * early_secret, client_early_traffic_secret, ... */
      uint8_t temp_secret[MAX_HASH_SIZE];
      unsigned temp_secret_size; /* depends on negotiated PRF size */
      uint8_t e_ckey
        [MAX_HASH_SIZE]; /* client_early_traffic_secret */
      uint8_t hs_ckey
        [MAX_HASH_SIZE]; /* client_hs_traffic_secret */
      uint8_t hs_skey
        [MAX_HASH_SIZE]; /* server_hs_traffic_secret */
      uint8_t ap_ckey
        [MAX_HASH_SIZE]; /* client_ap_traffic_secret */
      uint8_t ap_skey
        [MAX_HASH_SIZE]; /* server_ap_traffic_secret */
      uint8_t ap_expkey
        [MAX_HASH_SIZE]; /* {early_,}exporter_master_secret */
      uint8_t ap_rms[MAX_HASH_SIZE]; /* resumption_master_secret */
    } tls13; /* tls1.3 */

    /* Follow the SSL3.0 and TLS1.2 key exchanges */
    struct {
      /* For ECDH KX */
      struct {
        gnutls_pk_params_st params; /* private part */
        /* public part */
        bigint_t x;
        bigint_t y;
        gnutls_datum_t
          raw; /* public key used in ECDHX (point) */
      } ecdh;

      /* For DH KX */
      struct {
        gnutls_pk_params_st params;
        bigint_t client_Y;
      } dh;

      /* for SRP KX */
      struct {
        bigint_t srp_key;
        bigint_t srp_g;
        bigint_t srp_p;
        bigint_t A;
        bigint_t B;
        bigint_t u;
        bigint_t b;
        bigint_t a;
        bigint_t x;
      } srp;
    } tls12; /* from ssl3.0 to tls12 */
  } proto;

  /* binders / pre-shared keys in use; temporary storage.
   * On client side it will hold data for the resumption and external
   * PSKs After server hello is received the selected binder is set on 0 position
   * and HSK_PSK_SELECTED is set.
   *
   * On server side the first value is populated with
   * the selected PSK data if HSK_PSK_SELECTED flag is set. */
  struct binder_data_st binders[2];

  /* TLS pre-master key; applies to 1.2 and 1.3 */
  gnutls_datum_t key;

  uint8_t
    /* The key to encrypt and decrypt session tickets */
    session_ticket_key[TICKET_MASTER_KEY_SIZE],
    /* Static buffer for the previous key, whenever we need it */
    previous_ticket_key[TICKET_MASTER_KEY_SIZE],
    /* Initial key supplied by the caller */
    initial_stek[TICKET_MASTER_KEY_SIZE];

  /* Whether the initial_stek is set through
   * gnutls_session_ticket_enable_server() */
  bool stek_initialized;

  /* this is used to hold the peers authentication data
   */
  /* auth_info_t structures SHOULD NOT contain malloced
   * elements. Check gnutls_session_pack.c, and gnutls_auth.c.
   * Remember that this should be calloced!
   */
  void *auth_info;
  gnutls_credentials_type_t auth_info_type;
  int auth_info_size; /* needed in order to store to db for restoring
         */
  auth_cred_st *cred; /* used to specify keys/certificates etc */

  struct {
    uint64_t last_result;
    uint8_t was_rotated;
    gnutls_stek_rotation_callback_t cb;
  } totp;
};

typedef struct gnutls_key_st gnutls_key_st;

struct pin_info_st {
  gnutls_pin_callback_t cb;
  void *data;
};

struct record_state_st;
typedef struct record_state_st record_state_st;

struct record_parameters_st;
typedef struct record_parameters_st record_parameters_st;

#define GNUTLS_CIPHER_FLAG_ONLY_AEAD \
  (1                           \
   << 0) /* When set, this cipher is only available through the new AEAD API */
#define GNUTLS_CIPHER_FLAG_XOR_NONCE \
  (1                           \
   << 1) /* In this TLS AEAD cipher xor the implicit_iv with the nonce */
#define GNUTLS_CIPHER_FLAG_NO_REKEY \
  (1                          \
   << 2) /* whether this tls1.3 cipher doesn't need to rekey after 2^24 messages */
#define GNUTLS_CIPHER_FLAG_TAG_PREFIXED \
  (1 << 3) /* When set, this cipher prefixes authentication tag */

/* cipher and mac parameters */
typedef struct cipher_entry_st {
  const char *name;
  gnutls_cipher_algorithm_t id;
  uint16_t blocksize;
  uint16_t keysize;
  cipher_type_t type;
  uint16_t implicit_iv; /* the size of implicit IV - the IV generated but not sent */
  uint16_t explicit_iv; /* the size of explicit IV - the IV stored in record */
  uint16_t cipher_iv; /* the size of IV needed by the cipher */
  uint16_t tagsize;
  unsigned flags;
} cipher_entry_st;

typedef struct gnutls_cipher_suite_entry_st {
  const char *name;
  const uint8_t id[2];
  const char *canonical_name;
  gnutls_cipher_algorithm_t block_algorithm;
  gnutls_kx_algorithm_t kx_algorithm;
  gnutls_mac_algorithm_t mac_algorithm;
  gnutls_protocol_t min_version; /* this cipher suite is supported
           * from 'version' and above;
           */
  gnutls_protocol_t max_version; /* this cipher suite is not supported
           * after 'version' and above;
           */
  gnutls_protocol_t min_dtls_version; /* DTLS min version */
  gnutls_protocol_t max_dtls_version; /* DTLS max version */
  gnutls_mac_algorithm_t prf;
} gnutls_cipher_suite_entry_st;

#define MAX_HYBRID_GROUPS 2

typedef struct gnutls_group_entry_st {
  const char *name;
  gnutls_group_t id;
  const gnutls_datum_t *prime;
  const gnutls_datum_t *q;
  const gnutls_datum_t *generator;
  const unsigned *q_bits;
  gnutls_ecc_curve_t curve;
  gnutls_pk_algorithm_t pk;
  size_t pubkey_size; /* for KEM based groups */
  size_t ciphertext_size; /* for KEM based groups */
  gnutls_group_t ids[MAX_HYBRID_GROUPS + 1]; /* IDs of subgroups
                * comprising a
                * hybrid group,
                * terminated with
                * GNUTLS_GROUP_INVALID */
  unsigned tls_id; /* The RFC4492 namedCurve ID or TLS 1.3 group ID */
} gnutls_group_entry_st;

#define GNUTLS_MAC_FLAG_PREIMAGE_INSECURE \
  1 /* if this algorithm should not be trusted for pre-image attacks */
#define GNUTLS_MAC_FLAG_CONTINUOUS_MAC \
  (1 << 1) /* if this MAC should be used in a 'continuous' way in TLS */
#define GNUTLS_MAC_FLAG_PREIMAGE_INSECURE_REVERTIBLE \
  (1                                           \
   << 2) /* if this algorithm should not be trusted for pre-image attacks, but can be enabled through API */
#define GNUTLS_MAC_FLAG_ALLOW_INSECURE_REVERTIBLE \
  (1                                        \
   << 3) /* when checking with _gnutls_digest_is_insecure2, don't treat revertible setting as fatal */
#define GNUTLS_MAC_FLAG_XOF \
  (1 << 4) /* this function is an extendable output function (XOF) */
/* This structure is used both for MACs and digests
 */
typedef struct mac_entry_st {
  const char *name;
  const char *oid; /* OID of the hash - if it is a hash */
  const char *mac_oid; /* OID of the MAC algorithm - if it is a MAC */
  gnutls_mac_algorithm_t id;
  unsigned output_size;
  unsigned key_size;
  unsigned nonce_size;
  unsigned placeholder; /* if set, then not a real MAC */
  unsigned block_size; /* internal block size for HMAC */
  unsigned flags;
} mac_entry_st;

typedef struct {
  const char *name;
  gnutls_protocol_t id; /* gnutls internal version number */
  unsigned age; /* internal ordering by protocol age */
  uint8_t major; /* defined by the protocol */
  uint8_t minor; /* defined by the protocol */
  transport_t transport; /* Type of transport, stream or datagram */
  bool supported; /* 0 not supported, > 0 is supported */
  bool supported_revertible;
  bool explicit_iv;
  bool extensions; /* whether it supports extensions */
  bool selectable_sighash; /* whether signatures can be selected */
  bool selectable_prf; /* whether the PRF is ciphersuite-defined */

  /* if SSL3 is disabled this flag indicates that this protocol is a placeholder,
   * otherwise it prevents this protocol from being set as record version */
  bool obsolete;
  bool tls13_sem; /* The TLS 1.3 handshake semantics */
  bool false_start; /* That version can be used with false start */
  bool only_extension; /* negotiated only with an extension */
  bool post_handshake_auth; /* Supports the TLS 1.3 post handshake auth */
  bool key_shares; /* TLS 1.3 key share key exchange */
  bool multi_ocsp; /* TLS 1.3 multiple OCSP responses */
  /*
   * TLS versions modify the semantics of signature algorithms. This number
   * is there to distinguish signature algorithms semantics between versions
   * (maps to sign_algorithm_st->tls_sem)
   */
  uint8_t tls_sig_sem;
} version_entry_st;

/* STATE (cont) */

#include "hash_int.h"
#include "cipher_int.h"

typedef struct {
  uint8_t id[2]; /* used to be (in TLS 1.2) hash algorithm , PK algorithm */
  uint8_t tls_sem; /* should match the protocol version's tls_sig_sem. */
} sign_algorithm_st;

/* This structure holds parameters got from TLS extension
 * mechanism. (some extensions may hold parameters in auth_info_t
 * structures also - see SRP).
 */

#define MAX_VERIFY_DATA_SIZE 36 /* in SSL 3.0, 12 in TLS 1.0 */

/* auth_info_t structures now MAY contain malloced
 * elements.
 */

/* This structure and auth_info_t, are stored in the resume database,
 * and are restored, in case of resume.
 * Holds all the required parameters to resume the current
 * session.
 */

/* Note that the security parameters structure is set up after the
 * handshake has finished. The only value you may depend on while
 * the handshake is in progress is the cipher suite value.
 */
typedef struct {
  unsigned int entity; /* GNUTLS_SERVER or GNUTLS_CLIENT */

  /* The epoch used to read and write */
  uint16_t epoch_read;
  uint16_t epoch_write;

  /* The epoch that the next handshake will initialize. */
  uint16_t epoch_next;

  /* The epoch at index 0 of record_parameters. */
  uint16_t epoch_min;

  /* this is the ciphersuite we are going to use
   * moved here from internals in order to be restored
   * on resume;
   */
  const struct gnutls_cipher_suite_entry_st *cs;

  /* This is kept outside the ciphersuite entry as on certain
   * TLS versions we need a separate PRF MAC, i.e., MD5_SHA1. */
  const mac_entry_st *prf;

  uint8_t master_secret[GNUTLS_MASTER_SIZE];
  uint8_t client_random[GNUTLS_RANDOM_SIZE];
  uint8_t server_random[GNUTLS_RANDOM_SIZE];
  uint8_t session_id[GNUTLS_MAX_SESSION_ID_SIZE];
  uint8_t session_id_size;
  time_t timestamp;

  /* whether client has agreed in post handshake auth - only set on server side */
  uint8_t post_handshake_auth;

  /* The maximum amount of plaintext sent in a record,
   * negotiated with the peer.
   */
  uint16_t max_record_send_size;
  uint16_t max_record_recv_size;

  /* The maximum amount of plaintext sent in a record, set by
   * the programmer.
   */
  uint16_t max_user_record_send_size;
  uint16_t max_user_record_recv_size;

  /* The maximum amount of early data */
  uint32_t max_early_data_size;

  /* holds the negotiated certificate types */
  gnutls_certificate_type_t client_ctype;
  gnutls_certificate_type_t server_ctype;

  /* The selected (after server hello EC or DH group */
  const gnutls_group_entry_st *grp;

  /* Holds the signature algorithm that will be used in this session,
   * selected by the server at the time of Ciphersuite/certificate
   * selection - see select_sign_algorithm() */
  gnutls_sign_algorithm_t server_sign_algo;

  /* Holds the signature algorithm used in this session - If any */
  gnutls_sign_algorithm_t client_sign_algo;

  /* Whether the master secret negotiation will be according to
   * draft-ietf-tls-session-hash-01
   */
  uint8_t ext_master_secret;
  /* encrypt-then-mac -> rfc7366 */
  uint8_t etm;

  uint8_t client_auth_type; /* gnutls_credentials_type_t */
  uint8_t server_auth_type;

  /* Note: if you add anything in Security_Parameters struct, then
   * also modify CPY_COMMON in constate.c, and session_pack.c,
   * in order to save it in the session storage.
   */

  /* Used by extensions that enable supplemental data: Which ones
   * do that? Do they belong in security parameters?
   */
  int do_recv_supplemental, do_send_supplemental;
  const version_entry_st *pversion;
} security_parameters_st;

typedef struct api_aead_cipher_hd_st {
  cipher_hd_st ctx_enc;
} api_aead_cipher_hd_st;

struct record_state_st {
  /* mac keys can be as long as the hash size */
  uint8_t mac_key[MAX_HASH_SIZE];
  unsigned mac_key_size;

  uint8_t iv[MAX_CIPHER_IV_SIZE];
  unsigned iv_size;

  uint8_t key[MAX_CIPHER_KEY_SIZE];
  unsigned key_size;

  union {
    auth_cipher_hd_st tls12;
    api_aead_cipher_hd_st aead;
  } ctx;
  unsigned aead_tag_size;
  unsigned is_aead;
  uint64_t sequence_number;
  gnutls_record_encryption_level_t level;
};

/* These are used to resolve relative epochs. These values are just
   outside the 16 bit range to prevent off-by-one errors. An absolute
   epoch may be referred to by its numeric id in the range
   0x0000-0xffff. */
#define EPOCH_READ_CURRENT 70000
#define EPOCH_WRITE_CURRENT 70001
#define EPOCH_NEXT 70002

struct record_parameters_st {
  uint16_t epoch;
  int initialized;

  const cipher_entry_st *cipher;
  bool etm;
  const mac_entry_st *mac;

  /* for DTLS sliding window */
  uint64_t dtls_sw_next; /* The end point (next expected packet) of the sliding window without epoch */
  uint64_t dtls_sw_bits;
  unsigned dtls_sw_have_recv; /* whether at least a packet has been received */

  record_state_st read;
  record_state_st write;

  /* Whether this state is in use, i.e., if there is
     a pending handshake message waiting to be encrypted
     under this epoch's parameters.
   */
  int usage_cnt;
};

typedef struct {
  unsigned int priorities[MAX_ALGOS];
  unsigned int num_priorities;
} priority_st;

typedef enum {
  SR_DISABLED,
  SR_UNSAFE,
  SR_PARTIAL,
  SR_SAFE
} safe_renegotiation_t;

#define MAX_CIPHERSUITE_SIZE 256

typedef struct ciphersuite_list_st {
  const gnutls_cipher_suite_entry_st *entry[MAX_CIPHERSUITE_SIZE];
  unsigned int size;
} ciphersuite_list_st;

typedef struct group_list_st {
  const gnutls_group_entry_st *entry[MAX_ALGOS];
  unsigned int size;
  bool have_ffdhe;
} group_list_st;

typedef struct sign_algo_list_st {
  const struct gnutls_sign_entry_st *entry[MAX_ALGOS];
  unsigned int size;
} sign_algo_list_st;

#include "atomic.h"

typedef enum ext_master_secret_t {
  EMS_REQUEST,
  EMS_REQUIRE
} ext_master_secret_t;

/* For the external api */
struct gnutls_priority_st {
  priority_st protocol;
  priority_st client_ctype;
  priority_st server_ctype;

  /* The following are not necessary to be stored in
   * the structure; however they are required by the
   * external APIs: gnutls_priority_*_list() */
  priority_st _cipher;
  priority_st _mac;
  priority_st _kx;
  priority_st _sign_algo;
  priority_st _supported_ecc;

  /* the supported groups */
  group_list_st groups;

  /* the supported signature algorithms */
  sign_algo_list_st sigalg;

  /* the supported ciphersuites */
  ciphersuite_list_st cs;

  /* to disable record padding */
  bool no_extensions;

  /* to disable extensions shuffling */
  bool no_shuffle_extensions;

  safe_renegotiation_t sr;
  bool min_record_version;
  bool server_precedence;
  bool allow_server_key_usage_violation; /* for test suite purposes only */
  bool no_status_request;
  bool no_tickets;
  bool no_tickets_tls12;
  bool have_cbc;
  bool have_psk;
  bool force_etm;
  unsigned int additional_verify_flags;
  bool tls13_compat_mode;
  ext_master_secret_t force_ext_master_secret;

  /* TLS_FALLBACK_SCSV */
  bool fallback;

  /* The session's expected security level.
   * Will be used to determine the minimum DH bits,
   * (or the acceptable certificate security level).
   */
  gnutls_sec_param_t level;

  /* these should be accessed from
   * session->internals.VAR names */
  bool _allow_large_records;
  bool _allow_small_records;
  bool _no_etm;
  bool _no_ext_master_secret;
  bool _allow_key_usage_violation;
  bool _dumbfw;
  unsigned int _dh_prime_bits; /* old (deprecated) variable */

  DEF_ATOMIC_INT(usage_cnt);
};

/* Allow around 50KB of length-hiding padding
 * when using legacy padding,
 * or around 3.2MB when using new padding. */
#define DEFAULT_MAX_EMPTY_RECORDS 200

#define ENABLE_COMPAT(x)                    \
  (x)->allow_large_records = 1;       \
  (x)->allow_small_records = 1;       \
  (x)->no_etm = 1;                    \
  (x)->no_ext_master_secret = 1;      \
  (x)->allow_key_usage_violation = 1; \
  (x)->dumbfw = 1

#define ENABLE_PRIO_COMPAT(x)                \
  (x)->_allow_large_records = 1;       \
  (x)->_allow_small_records = 1;       \
  (x)->_no_etm = 1;                    \
  (x)->_no_ext_master_secret = 1;      \
  (x)->_allow_key_usage_violation = 1; \
  (x)->_dumbfw = 1

/* DH and RSA parameters types.
 */
typedef struct gnutls_dh_params_int {
  /* [0] is the prime, [1] is the generator, [2] is Q if available.
   */
  bigint_t params[3];
  int q_bits; /* length of q in bits. If zero then length is unknown.
         */
} dh_params_st;

/* TLS 1.3 session ticket
 */
typedef struct {
  struct timespec arrival_time;
  struct timespec creation_time;
  uint32_t lifetime;
  uint32_t age_add;
  uint8_t nonce[255];
  size_t nonce_size;
  const mac_entry_st *prf;
  uint8_t resumption_master_secret[MAX_HASH_SIZE];
  gnutls_datum_t ticket;
} tls13_ticket_st;

/* DTLS session state
 */
typedef struct {
  /* HelloVerifyRequest DOS prevention cookie */
  gnutls_datum_t dcookie;

  /* For DTLS handshake fragmentation and reassembly. */
  uint16_t hsk_write_seq;
  /* the sequence number of the expected packet */
  unsigned int hsk_read_seq;
  uint16_t mtu;

  /* a flight transmission is in process */
  bool flight_init;
  /* whether this is the last flight in the protocol  */
  bool last_flight;

  /* the retransmission timeout in milliseconds */
  unsigned int retrans_timeout_ms;

  unsigned int hsk_hello_verify_requests;

  /* The actual retrans_timeout for the next message (e.g. doubled or so)
   */
  unsigned int actual_retrans_timeout_ms;

  /* timers to handle async handshake after gnutls_handshake()
   * has terminated. Required to handle retransmissions.
   */
  time_t async_term;

  /* last retransmission triggered by record layer */
  struct timespec last_retransmit;
  unsigned int packets_dropped;
} dtls_st;

typedef struct tfo_st {
  int fd;
  int flags;
  bool connect_only; /* a previous sendmsg() failed, attempting connect() */
  struct sockaddr_storage connect_addr;
  socklen_t connect_addrlen;
} tfo_st;

typedef struct {
  /* holds all the parsed data received by the record layer */
  mbuffer_head_st record_buffer;

  int handshake_hash_buffer_prev_len; /* keeps the length of handshake_hash_buffer, excluding
             * the last received message */
  unsigned handshake_hash_buffer_client_hello_len; /* if non-zero it is the length of data until the client hello message */
  unsigned handshake_hash_buffer_client_kx_len; /* if non-zero it is the length of data until the
               * the client key exchange message */
  unsigned handshake_hash_buffer_server_finished_len; /* if non-zero it is the length of data until the
                 * the server finished message */
  unsigned handshake_hash_buffer_client_finished_len; /* if non-zero it is the length of data until the
                 * the client finished message */
  gnutls_buffer_st
    handshake_hash_buffer; /* used to keep the last received handshake
             * message */

  bool resumable; /* if we can resume that session */

  send_ticket_state_t
    ticket_state; /* used by gnutls_session_ticket_send() */
  bye_state_t bye_state; /* used by gnutls_bye() */
  reauth_state_t reauth_state; /* used by gnutls_reauth() */

  handshake_state_t handshake_final_state;
  handshake_state_t handshake_state; /* holds
             * a number which indicates where
             * the handshake procedure has been
             * interrupted. If it is 0 then
             * no interruption has happened.
             */

  bool invalid_connection; /* if this session is valid */

  bool may_not_read; /* if it's 0 then we can read/write, otherwise it's forbidden to read/write
         */
  bool may_not_write;
  bool read_eof; /* non-zero if we have received a closure alert. */

  int last_alert; /* last alert received */

  /* The last handshake messages sent or received.
   */
  int last_handshake_in;
  int last_handshake_out;

  /* priorities */
  struct gnutls_priority_st *priorities;

  /* variables directly set when setting the priorities above, or
   * when overriding them */
  bool allow_large_records;
  bool allow_small_records;
  bool no_etm;
  bool no_ext_master_secret;
  bool allow_key_usage_violation;
  bool dumbfw;

  /* old (deprecated) variable. This is used for both srp_prime_bits
   * and dh_prime_bits as they don't overlap */
  /* For SRP: minimum bits to allow for SRP
   * use gnutls_srp_set_prime_bits() to adjust it.
   */
  uint16_t dh_prime_bits; /* srp_prime_bits */

  /* resumed session */
  bool resumed; /* if we are resuming a session */

  /* server side: non-zero if resumption was requested by client
   * client side: non-zero if we set resumption parameters */
  bool resumption_requested;
  security_parameters_st resumed_security_parameters;
  gnutls_datum_t
    resumption_data; /* copy of input to gnutls_session_set_data() */

  /* These buffers are used in the handshake
   * protocol only. freed using _gnutls_handshake_io_buffer_clear();
   */
  mbuffer_head_st handshake_send_buffer;
  mbuffer_head_st handshake_header_recv_buffer;
  handshake_buffer_st handshake_recv_buffer[MAX_HANDSHAKE_MSGS];
  int handshake_recv_buffer_size;

  /* this buffer holds a record packet -mostly used for
   * non blocking IO.
   */
  mbuffer_head_st
    record_recv_buffer; /* buffer holding the unparsed record that is currently
             * being received */
  mbuffer_head_st record_send_buffer; /* holds cached data
             * for the gnutls_io_write_buffered()
             * function.
             */
  size_t record_send_buffer_user_size; /* holds the
             * size of the user specified data to
             * send.
             */

  mbuffer_head_st early_data_recv_buffer;
  gnutls_buffer_st early_data_presend_buffer;

  record_send_state_t rsend_state;
  /* buffer used temporarily during key update */
  gnutls_buffer_st record_key_update_buffer;
  gnutls_buffer_st record_presend_buffer; /* holds cached data
             * for the gnutls_record_send()
             * function.
             */

  /* buffer used temporarily during TLS1.3 reauthentication */
  gnutls_buffer_st reauth_buffer;

  time_t expire_time; /* after expire_time seconds this session will expire */
  const struct mod_auth_st_int
    *auth_struct; /* used in handshake packets and KX algorithms */

  /* this is the highest version available
   * to the peer. (advertised version).
   * This is obtained by the Handshake Client Hello
   * message. (some implementations read the Record version)
   */
  uint8_t adv_version_major;
  uint8_t adv_version_minor;

  /* if this is non zero a certificate request message
   * will be sent to the client. - only if the ciphersuite
   * supports it. In server side it contains GNUTLS_CERT_REQUIRE
   * or similar.
   */
  gnutls_certificate_request_t send_cert_req;

  /* callback to print the full path of certificate
   * validation to the trusted root.
   */
  gnutls_verify_output_function *cert_output_callback;

  size_t max_handshake_data_buffer_size;

  /* PUSH & PULL functions.
   */
  gnutls_pull_timeout_func pull_timeout_func;
  gnutls_pull_func pull_func;
  gnutls_push_func push_func;
  gnutls_vec_push_func vec_push_func;
  gnutls_errno_func errno_func;
  /* Holds the first argument of PUSH and PULL
   * functions;
   */
  gnutls_transport_ptr_t transport_recv_ptr;
  gnutls_transport_ptr_t transport_send_ptr;

  /* STORE & RETRIEVE functions. Only used if other
   * backend than gdbm is used.
   */
  gnutls_db_store_func db_store_func;
  gnutls_db_retr_func db_retrieve_func;
  gnutls_db_remove_func db_remove_func;
  void *db_ptr;

  /* post client hello callback (server side only)
   */
  gnutls_handshake_post_client_hello_func user_hello_func;
  /* handshake hook function */
  gnutls_handshake_hook_func h_hook;
  unsigned int h_type; /* the hooked type */
  int16_t h_post; /* whether post-generation/receive */
  gnutls_handshake_read_func h_read_func;
  gnutls_handshake_secret_func h_secret_func;
  gnutls_alert_read_func alert_read_func;

  gnutls_keylog_func keylog_func;

  /* holds the selected certificate and key.
   * use _gnutls_selected_certs_deinit() and _gnutls_selected_certs_set()
   * to change them.
   */
  gnutls_pcert_st *selected_cert_list;
  uint16_t selected_cert_list_length;
  struct gnutls_privkey_st *selected_key;

  /* new callbacks such as gnutls_certificate_retrieve_function3
   * set the selected_ocsp datum values. The older OCSP callback-based
   * functions, set the ocsp_func. The former takes precedence when
   * set.
   */
  gnutls_ocsp_data_st *selected_ocsp;
  uint16_t selected_ocsp_length;
  gnutls_status_request_ocsp_func selected_ocsp_func;
  void *selected_ocsp_func_ptr;
  bool selected_need_free;

  /* This holds the default version that our first
   * record packet will have. */
  uint8_t default_record_version[2];
  uint8_t default_hello_version[2];

  void *user_ptr;

  /* Holds 0 if the last called function was interrupted while
   * receiving, and non zero otherwise.
   */
  bool direction;

  /* If non zero the server will not advertise the CA's he
   * trusts (do not send an RDN sequence).
   */
  bool ignore_rdn_sequence;

  /* This is used to set an arbitrary version in the RSA
   * PMS secret. Can be used by clients to test whether the
   * server checks that version. (** only used in gnutls-cli-debug)
   */
  uint8_t rsa_pms_version[2];

  /* To avoid using global variables, and especially on Windows where
   * the application may use a different errno variable than GnuTLS,
   * it is possible to use gnutls_transport_set_errno to set a
   * session-specific errno variable in the user-replaceable push/pull
   * functions.  This value is used by the send/recv functions.  (The
   * strange name of this variable is because 'errno' is typically
   * #define'd.)
   */
  int errnum;

  /* A handshake process has been completed */
  bool initial_negotiation_completed;
  void *post_negotiation_lock; /* protects access to the variable above
           * in the cases where negotiation is incomplete
           * after gnutls_handshake() - early/false start */

  /* The type of transport protocol; stream or datagram */
  transport_t transport;

  /* DTLS session state */
  dtls_st dtls;
  /* Protect from infinite loops due to GNUTLS_E_LARGE_PACKET non-handling
   * or due to multiple alerts being received. */
  unsigned handshake_suspicious_loops;
  /* should be non-zero when a handshake is in progress */
  bool handshake_in_progress;

  /* if set it means that the master key was set using
   * gnutls_session_set_master() rather than being negotiated. */
  bool premaster_set;

  unsigned int cb_tls_unique_len;
  unsigned char cb_tls_unique[MAX_VERIFY_DATA_SIZE];

  /* starting time of current handshake */
  struct timespec handshake_start_time;

  /* expected end time of current handshake (start+timeout);
   * this is only filled if a handshake_time_ms is set. */
  struct timespec handshake_abs_timeout;

  /* An estimation of round-trip time under TLS1.3; populated in client side only */
  unsigned ertt;

  unsigned int handshake_timeout_ms; /* timeout in milliseconds */
  unsigned int record_timeout_ms; /* timeout in milliseconds */

  /* saved context of post handshake certificate request. In
   * client side is what we received in server's certificate request;
   * in server side is what we sent to client. */
  gnutls_datum_t post_handshake_cr_context;
  /* it is a copy of the handshake hash buffer if post handshake is used */
  gnutls_buffer_st post_handshake_hash_buffer;

/* When either of PSK or DHE-PSK is received */
#define HSK_PSK_KE_MODES_RECEIVED                        \
  (HSK_PSK_KE_MODE_PSK | HSK_PSK_KE_MODE_DHE_PSK | \
   HSK_PSK_KE_MODE_INVALID)

#define HSK_CRT_VRFY_EXPECTED 1
#define HSK_CRT_ASKED (1 << 2)
#define HSK_HRR_SENT (1 << 3)
#define HSK_HRR_RECEIVED (1 << 4)
#define HSK_CRT_REQ_SENT (1 << 5)
#define HSK_COMP_CRT_REQ_SENT \
  (1 << 6) /* whether certificate compression has been requested */
#define HSK_KEY_UPDATE_ASKED (1 << 7) /* flag is not used during handshake */
#define HSK_FALSE_START_USED (1 << 8) /* TLS1.2 only */
#define HSK_HAVE_FFDHE \
  (1 << 9) /* whether the peer has advertised at least an FFDHE group */
#define HSK_USED_FFDHE \
  (1 << 10) /* whether ffdhe was actually negotiated and used */
#define HSK_PSK_KE_MODES_SENT (1 << 11)
#define HSK_PSK_KE_MODE_PSK \
  (1 << 12) /* client: whether PSK without DH is allowed,
           * server: whether PSK without DH is selected. */
#define HSK_PSK_KE_MODE_INVALID \
  (1 << 13) /* server: no compatible PSK modes were seen */
#define HSK_PSK_KE_MODE_DHE_PSK \
  (1 << 14) /* server: whether PSK with DH is selected
           * client: whether PSK with DH is allowed
           */
#define HSK_PSK_SELECTED \
  (1               \
   << 15) /* server: whether PSK was selected, either for resumption or not;
           *         on resumption session->internals.resumed will be set as well.
           * client: the same */
#define HSK_KEY_SHARE_SENT (1 << 16) /* server: key share was sent to client */
#define HSK_KEY_SHARE_RECEIVED \
  (1 << 17) /* client: key share was received
           * server: key share was received and accepted */
#define HSK_TLS13_TICKET_SENT \
  (1 << 18) /* client: sent a ticket under TLS1.3;
           * server: a ticket was sent to client.
           */
#define HSK_TLS12_TICKET_SENT \
  (1 << 19) /* client: sent a ticket under TLS1.2;
           * server: a ticket was sent to client.
           */
#define HSK_TICKET_RECEIVED \
  (1 << 20) /* client: a session ticket was received */
#define HSK_EARLY_START_USED (1 << 21)
#define HSK_EARLY_DATA_IN_FLIGHT \
  (1 << 22) /* client: sent early_data extension in ClientHello
             * server: early_data extension was seen in ClientHello
             */
#define HSK_EARLY_DATA_ACCEPTED \
  (1                      \
   << 23) /* client: early_data extension was seen in EncryptedExtensions
           * server: intend to process early data
           */
#define HSK_RECORD_SIZE_LIMIT_NEGOTIATED (1 << 24)
#define HSK_RECORD_SIZE_LIMIT_SENT \
  (1 << 25) /* record_size_limit extension was sent */
#define HSK_RECORD_SIZE_LIMIT_RECEIVED \
  (1                             \
   << 26) /* server: record_size_limit extension was seen but not accepted yet */
#define HSK_OCSP_REQUESTED \
  (1 << 27) /* server: client requested OCSP stapling */
#define HSK_CLIENT_OCSP_REQUESTED \
  (1 << 28) /* client: server requested OCSP stapling */
#define HSK_SERVER_HELLO_RECEIVED \
  (1 << 29) /* client: Server Hello message has been received */

  /* The hsk_flags are for use within the ongoing handshake;
   * they are reset to zero prior to handshake start by gnutls_handshake. */
  unsigned hsk_flags;
  struct timespec last_key_update;
  unsigned key_update_count;
  /* Read-only pointer to the full ClientHello message */
  gnutls_buffer_st full_client_hello;
  /* The offset at which extensions start in the ClientHello buffer */
  int extensions_offset;

  gnutls_buffer_st hb_local_data;
  gnutls_buffer_st hb_remote_data;
  struct timespec
    hb_ping_start; /* timestamp: when first HeartBeat ping was sent */
  struct timespec
    hb_ping_sent; /* timestamp: when last HeartBeat ping was sent */
  unsigned int
    hb_actual_retrans_timeout_ms; /* current timeout, in milliseconds */
  unsigned int
    hb_retrans_timeout_ms; /* the default timeout, in milliseconds */
  unsigned int hb_total_timeout_ms; /* the total timeout, in milliseconds */

  bool ocsp_check_ok; /* will be zero if the OCSP response TLS extension
         * check failed (OCSP was old/unrelated or so). */

  heartbeat_state_t hb_state; /* for ping */

  recv_state_t recv_state; /* state of the receive function */

  /* if set, server and client random were set by the application */
  bool sc_random_set;

#define INT_FLAG_NO_TLS13 (1LL << 60)
  uint64_t flags; /* the flags in gnutls_init() and GNUTLS_INT_FLAGS */

  /* a verify callback to override the verify callback from the credentials
   * structure */
  gnutls_certificate_verify_function *verify_callback;
  gnutls_typed_vdata_st *vc_data;
  gnutls_typed_vdata_st vc_sdata;
  unsigned vc_elements;
  unsigned vc_status;
  unsigned int
    additional_verify_flags; /* may be set by priorities or the vc functions */

  /* we append the verify flags because these can be set,
   * either by this function or by gnutls_session_set_verify_cert().
   * However, we ensure that a single profile is set. */
#define ADD_PROFILE_VFLAGS(session, vflags)                           \
  do {                                                          \
    if ((session->internals.additional_verify_flags &     \
         GNUTLS_VFLAGS_PROFILE_MASK) &&                   \
        (vflags & GNUTLS_VFLAGS_PROFILE_MASK))            \
      session->internals.additional_verify_flags &= \
        ~GNUTLS_VFLAGS_PROFILE_MASK;          \
    session->internals.additional_verify_flags |= vflags; \
  } while (0)

  /* the SHA256 hash of the peer's certificate */
  uint8_t cert_hash[32];
  bool cert_hash_set;

  /* The saved username from PSK or SRP auth */
  char *saved_username;
  /* Length of the saved username without the NULL terminating byte.
   * Must be set to -1 when saved username is NULL
   */
  int saved_username_size;

  /* Needed for TCP Fast Open (TFO), set by gnutls_transport_set_fastopen() */
  tfo_st tfo;

  struct gnutls_supplemental_entry_st *rsup;
  unsigned rsup_size;

  struct hello_ext_entry_st *rexts;
  unsigned rexts_size;

  struct { /* ext_data[id] contains data for extension_t id */
    gnutls_ext_priv_data_t priv;
    gnutls_ext_priv_data_t resumed_priv;
    uint8_t set;
    uint8_t resumed_set;
  } ext_data[MAX_EXT_TYPES];

  /* In case of a client holds the extensions we sent to the peer;
   * otherwise the extensions we received from the client. This is
   * an OR of (1<<extensions_t values).
   */
  ext_track_t used_exts;

  gnutls_ext_flags_t
    ext_msg; /* accessed through _gnutls_ext_get/set_msg() */

  /* this is not the negotiated max_record_recv_size, but the actual maximum
   * receive size */
  unsigned max_recv_size;

  /* candidate groups to be selected for security params groups, they are
   * prioritized in isolation under TLS1.2 */
  const gnutls_group_entry_st *cand_ec_group;
  const gnutls_group_entry_st *cand_dh_group;
  /* used under TLS1.3+ */
  const gnutls_group_entry_st *cand_group;

  /* the ciphersuite received in HRR */
  uint8_t hrr_cs[2];

  /* this is only used under TLS1.2 or earlier */
  int session_ticket_renew;

  tls13_ticket_st tls13_ticket;

  /* the amount of early data received so far */
  uint32_t early_data_received;

  /* anti-replay measure for 0-RTT mode */
  gnutls_anti_replay_t anti_replay;

  /* Protects _gnutls_epoch_gc() from _gnutls_epoch_get(); these may be
   * called in parallel when false start is used and false start is used. */
  void *epoch_lock;

  /* indicates whether or not was KTLS initialized properly. */
  int ktls_enabled;

  /* Compression method for certificate compression */
  gnutls_compression_method_t compress_certificate_method;

  /* To shuffle extension sending order */
  extensions_t client_hello_exts[MAX_EXT_TYPES];
  bool client_hello_exts_set;

  /* If you add anything here, check _gnutls_handshake_internal_state_clear().
   */
} internals_st;

/* Maximum number of epochs we keep around. */
#define MAX_EPOCH_INDEX 4

#define reset_cand_groups(session)                                            \
  session->internals.cand_ec_group = session->internals.cand_dh_group = \
    session->internals.cand_group = NULL

struct gnutls_session_int {
  security_parameters_st security_parameters;
  record_parameters_st *record_parameters[MAX_EPOCH_INDEX];
  internals_st internals;
  gnutls_key_st key;
};

/* functions
 */
void _gnutls_free_auth_info(gnutls_session_t session);

/* These two macros return the advertised TLS version of
 * the peer.
 */
#define _gnutls_get_adv_version_major(session) \
  session->internals.adv_version_major

#define _gnutls_get_adv_version_minor(session) \
  session->internals.adv_version_minor

#define set_adv_version(session, major, minor)        \
  session->internals.adv_version_major = major; \
  session->internals.adv_version_minor = minor

int _gnutls_is_secure_mem_null(const void *);

inline static const version_entry_st *get_version(gnutls_session_t session)
{
  return session->security_parameters.pversion;
}

inline static unsigned get_num_version(gnutls_session_t session)
{
  if (likely(session->security_parameters.pversion != NULL))
    return session->security_parameters.pversion->id;
  else
    return GNUTLS_VERSION_UNKNOWN;
}

void _gnutls_priority_update_fips(void);
void _gnutls_priority_update_non_aesni(void);
extern unsigned _gnutls_disable_tls13;

#define timespec_sub_ms _gnutls_timespec_sub_ms
unsigned int
/* returns a-b in ms */
timespec_sub_ms(struct timespec *a, struct timespec *b);

inline static int _gnutls_timespec_cmp(struct timespec *a, struct timespec *b)
{
  if (a->tv_sec < b->tv_sec)
    return -1;
  if (a->tv_sec > b->tv_sec)
    return 1;
  if (a->tv_nsec < b->tv_nsec)
    return -1;
  if (a->tv_nsec > b->tv_nsec)
    return 1;
  return 0;
}

#include "algorithms.h"
inline static int _gnutls_set_current_version(gnutls_session_t s, unsigned v)
{
  s->security_parameters.pversion = version_to_entry(v);
  if (s->security_parameters.pversion == NULL) {
    return GNUTLS_E_UNSUPPORTED_VERSION_PACKET;
  }
  return 0;
}

/* Returns the maximum amount of the plaintext to be sent, considering
 * both user-specified/negotiated maximum values.
 */
inline static size_t max_record_send_size(gnutls_session_t session)
{
  size_t max;

  max = MIN(session->security_parameters.max_record_send_size,
      session->security_parameters.max_user_record_send_size);

  if (IS_DTLS(session))
    max = MIN(gnutls_dtls_get_data_mtu(session), max);

  return max;
}

/* Returns the during the handshake negotiated certificate type(s).
 * See state.c for the full function documentation.
 *
 * This function is made static inline for optimization reasons.
 */
inline static gnutls_certificate_type_t
get_certificate_type(gnutls_session_t session, gnutls_ctype_target_t target)
{
  switch (target) {
  case GNUTLS_CTYPE_CLIENT:
    return session->security_parameters.client_ctype;
    break;
  case GNUTLS_CTYPE_SERVER:
    return session->security_parameters.server_ctype;
    break;
  case GNUTLS_CTYPE_OURS:
    if (IS_SERVER(session)) {
      return session->security_parameters.server_ctype;
    } else {
      return session->security_parameters.client_ctype;
    }
    break;
  case GNUTLS_CTYPE_PEERS:
    if (IS_SERVER(session)) {
      return session->security_parameters.client_ctype;
    } else {
      return session->security_parameters.server_ctype;
    }
    break;
  default: // Illegal parameter passed
    return GNUTLS_CRT_UNKNOWN;
  }
}

/* Macros to aide constant time/mem checks */
#define CONSTCHECK_NOT_EQUAL(a, b) ((-((uint32_t)(a) ^ (uint32_t)(b))) >> 31)
#define CONSTCHECK_EQUAL(a, b) (1U - CONSTCHECK_NOT_EQUAL(a, b))

extern unsigned int _gnutls_global_version;

bool _gnutls_config_is_ktls_enabled(void);
bool _gnutls_config_is_rsa_pkcs1_encrypt_allowed(void);

#endif /* GNUTLS_LIB_GNUTLS_INT_H */

Coverage Report

Created: 2025-03-18 06:55

Line	Count	Source (jump to first uncovered line)
1		/*
2		* Copyright (C) 2000-2016 Free Software Foundation, Inc.
3		* Copyright (C) 2015-2018 Red Hat, Inc.
4		*
5		* Author: Nikos Mavrogiannopoulos
6		*
7		* This file is part of GnuTLS.
8		*
9		* The GnuTLS is free software; you can redistribute it and/or
10		* modify it under the terms of the GNU Lesser General Public License
11		* as published by the Free Software Foundation; either version 2.1 of
12		* the License, or (at your option) any later version.
13		*
14		* This library is distributed in the hope that it will be useful, but
15		* WITHOUT ANY WARRANTY; without even the implied warranty of
16		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17		* Lesser General Public License for more details.
18		*
19		* You should have received a copy of the GNU Lesser General Public License
20		* along with this program. If not, see <https://www.gnu.org/licenses/>
21		*
22		*/
23
24		#ifndef GNUTLS_LIB_GNUTLS_INT_H
25		#define GNUTLS_LIB_GNUTLS_INT_H
26
27		#ifdef HAVE_CONFIG_H
28		#include "config.h"
29		#endif
30
31		#include <stddef.h>
32		#include <string.h>
33		#include <stdlib.h>
34		#include <stdio.h>
35		#include <ctype.h>
36		#include <limits.h>
37		#include <stdint.h>
38		#include <stdbool.h>
39		#include <assert.h>