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      1 /*
      2  * Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved.
      3  *
      4  * Licensed under the OpenSSL license (the "License").  You may not use
      5  * this file except in compliance with the License.  You can obtain a copy
      6  * in the file LICENSE in the source distribution or at
      7  * https://www.openssl.org/source/license.html
      8  */
      9 
     10 /*****************************************************************************
     11  *                                                                           *
     12  * These enums should be considered PRIVATE to the state machine. No         *
     13  * non-state machine code should need to use these                           *
     14  *                                                                           *
     15  *****************************************************************************/
     16 /*
     17  * Valid return codes used for functions performing work prior to or after
     18  * sending or receiving a message
     19  */
     20 typedef enum {
     21     /* Something went wrong */
     22     WORK_ERROR,
     23     /* We're done working and there shouldn't be anything else to do after */
     24     WORK_FINISHED_STOP,
     25     /* We're done working move onto the next thing */
     26     WORK_FINISHED_CONTINUE,
     27     /* We're working on phase A */
     28     WORK_MORE_A,
     29     /* We're working on phase B */
     30     WORK_MORE_B,
     31     /* We're working on phase C */
     32     WORK_MORE_C
     33 } WORK_STATE;
     34 
     35 /* Write transition return codes */
     36 typedef enum {
     37     /* Something went wrong */
     38     WRITE_TRAN_ERROR,
     39     /* A transition was successfully completed and we should continue */
     40     WRITE_TRAN_CONTINUE,
     41     /* There is no more write work to be done */
     42     WRITE_TRAN_FINISHED
     43 } WRITE_TRAN;
     44 
     45 /* Message flow states */
     46 typedef enum {
     47     /* No handshake in progress */
     48     MSG_FLOW_UNINITED,
     49     /* A permanent error with this connection */
     50     MSG_FLOW_ERROR,
     51     /* We are reading messages */
     52     MSG_FLOW_READING,
     53     /* We are writing messages */
     54     MSG_FLOW_WRITING,
     55     /* Handshake has finished */
     56     MSG_FLOW_FINISHED
     57 } MSG_FLOW_STATE;
     58 
     59 /* Read states */
     60 typedef enum {
     61     READ_STATE_HEADER,
     62     READ_STATE_BODY,
     63     READ_STATE_POST_PROCESS
     64 } READ_STATE;
     65 
     66 /* Write states */
     67 typedef enum {
     68     WRITE_STATE_TRANSITION,
     69     WRITE_STATE_PRE_WORK,
     70     WRITE_STATE_SEND,
     71     WRITE_STATE_POST_WORK
     72 } WRITE_STATE;
     73 
     74 typedef enum {
     75     /* The enc_write_ctx can be used normally */
     76     ENC_WRITE_STATE_VALID,
     77     /* The enc_write_ctx cannot be used */
     78     ENC_WRITE_STATE_INVALID,
     79     /* Write alerts in plaintext, but otherwise use the enc_write_ctx */
     80     ENC_WRITE_STATE_WRITE_PLAIN_ALERTS
     81 } ENC_WRITE_STATES;
     82 
     83 typedef enum {
     84     /* The enc_read_ctx can be used normally */
     85     ENC_READ_STATE_VALID,
     86     /* We may receive encrypted or plaintext alerts */
     87     ENC_READ_STATE_ALLOW_PLAIN_ALERTS
     88 } ENC_READ_STATES;
     89 
     90 /*****************************************************************************
     91  *                                                                           *
     92  * This structure should be considered "opaque" to anything outside of the   *
     93  * state machine. No non-state machine code should be accessing the members  *
     94  * of this structure.                                                        *
     95  *                                                                           *
     96  *****************************************************************************/
     97 
     98 struct ossl_statem_st {
     99     MSG_FLOW_STATE state;
    100     WRITE_STATE write_state;
    101     WORK_STATE write_state_work;
    102     READ_STATE read_state;
    103     WORK_STATE read_state_work;
    104     OSSL_HANDSHAKE_STATE hand_state;
    105     /* The handshake state requested by an API call (e.g. HelloRequest) */
    106     OSSL_HANDSHAKE_STATE request_state;
    107     int in_init;
    108     int read_state_first_init;
    109     /* true when we are actually in SSL_accept() or SSL_connect() */
    110     int in_handshake;
    111     /*
    112      * True when are processing a "real" handshake that needs cleaning up (not
    113      * just a HelloRequest or similar).
    114      */
    115     int cleanuphand;
    116     /* Should we skip the CertificateVerify message? */
    117     unsigned int no_cert_verify;
    118     int use_timer;
    119     ENC_WRITE_STATES enc_write_state;
    120     ENC_READ_STATES enc_read_state;
    121 };
    122 typedef struct ossl_statem_st OSSL_STATEM;
    123 
    124 /*****************************************************************************
    125  *                                                                           *
    126  * The following macros/functions represent the libssl internal API to the   *
    127  * state machine. Any libssl code may call these functions/macros            *
    128  *                                                                           *
    129  *****************************************************************************/
    130 
    131 __owur int ossl_statem_accept(SSL *s);
    132 __owur int ossl_statem_connect(SSL *s);
    133 void ossl_statem_clear(SSL *s);
    134 void ossl_statem_set_renegotiate(SSL *s);
    135 void ossl_statem_fatal(SSL *s, int al, int func, int reason, const char *file,
    136                        int line);
    137 # define SSL_AD_NO_ALERT    -1
    138 # ifndef OPENSSL_NO_ERR
    139 #  define SSLfatal(s, al, f, r)  ossl_statem_fatal((s), (al), (f), (r), \
    140                                                    OPENSSL_FILE, OPENSSL_LINE)
    141 # else
    142 #  define SSLfatal(s, al, f, r)  ossl_statem_fatal((s), (al), (f), (r), NULL, 0)
    143 # endif
    144 
    145 int ossl_statem_in_error(const SSL *s);
    146 void ossl_statem_set_in_init(SSL *s, int init);
    147 int ossl_statem_get_in_handshake(SSL *s);
    148 void ossl_statem_set_in_handshake(SSL *s, int inhand);
    149 __owur int ossl_statem_skip_early_data(SSL *s);
    150 void ossl_statem_check_finish_init(SSL *s, int send);
    151 void ossl_statem_set_hello_verify_done(SSL *s);
    152 __owur int ossl_statem_app_data_allowed(SSL *s);
    153 __owur int ossl_statem_export_allowed(SSL *s);
    154 __owur int ossl_statem_export_early_allowed(SSL *s);
    155 
    156 /* Flush the write BIO */
    157 int statem_flush(SSL *s);
    158