ssl_internal.h

00001 /**
00002  * \file ssl_internal.h
00003  *
00004  * \brief Internal functions shared by the SSL modules
00005  */
00006 /*
00007  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
00008  *  SPDX-License-Identifier: Apache-2.0
00009  *
00010  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
00011  *  not use this file except in compliance with the License.
00012  *  You may obtain a copy of the License at
00013  *
00014  *  http://www.apache.org/licenses/LICENSE-2.0
00015  *
00016  *  Unless required by applicable law or agreed to in writing, software
00017  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
00018  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00019  *  See the License for the specific language governing permissions and
00020  *  limitations under the License.
00021  *
00022  *  This file is part of mbed TLS (https://tls.mbed.org)
00023  */
00024 #ifndef MBEDTLS_SSL_INTERNAL_H
00025 #define MBEDTLS_SSL_INTERNAL_H
00026 
00027 #include "ssl.h"
00028 #include "cipher.h"
00029 
00030 #if defined(MBEDTLS_MD5_C)
00031 #include "md5.h"
00032 #endif
00033 
00034 #if defined(MBEDTLS_SHA1_C)
00035 #include "sha1.h"
00036 #endif
00037 
00038 #if defined(MBEDTLS_SHA256_C)
00039 #include "sha256.h"
00040 #endif
00041 
00042 #if defined(MBEDTLS_SHA512_C)
00043 #include "sha512.h"
00044 #endif
00045 
00046 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
00047 #include "ecjpake.h"
00048 #endif
00049 
00050 #if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
00051     !defined(inline) && !defined(__cplusplus)
00052 #define inline __inline
00053 #endif
00054 
00055 /* Determine minimum supported version */
00056 #define MBEDTLS_SSL_MIN_MAJOR_VERSION           MBEDTLS_SSL_MAJOR_VERSION_3
00057 
00058 #if defined(MBEDTLS_SSL_PROTO_SSL3)
00059 #define MBEDTLS_SSL_MIN_MINOR_VERSION           MBEDTLS_SSL_MINOR_VERSION_0
00060 #else
00061 #if defined(MBEDTLS_SSL_PROTO_TLS1)
00062 #define MBEDTLS_SSL_MIN_MINOR_VERSION           MBEDTLS_SSL_MINOR_VERSION_1
00063 #else
00064 #if defined(MBEDTLS_SSL_PROTO_TLS1_1)
00065 #define MBEDTLS_SSL_MIN_MINOR_VERSION           MBEDTLS_SSL_MINOR_VERSION_2
00066 #else
00067 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
00068 #define MBEDTLS_SSL_MIN_MINOR_VERSION           MBEDTLS_SSL_MINOR_VERSION_3
00069 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
00070 #endif /* MBEDTLS_SSL_PROTO_TLS1_1 */
00071 #endif /* MBEDTLS_SSL_PROTO_TLS1   */
00072 #endif /* MBEDTLS_SSL_PROTO_SSL3   */
00073 
00074 #define MBEDTLS_SSL_MIN_VALID_MINOR_VERSION MBEDTLS_SSL_MINOR_VERSION_1
00075 #define MBEDTLS_SSL_MIN_VALID_MAJOR_VERSION MBEDTLS_SSL_MAJOR_VERSION_3
00076 
00077 /* Determine maximum supported version */
00078 #define MBEDTLS_SSL_MAX_MAJOR_VERSION           MBEDTLS_SSL_MAJOR_VERSION_3
00079 
00080 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
00081 #define MBEDTLS_SSL_MAX_MINOR_VERSION           MBEDTLS_SSL_MINOR_VERSION_3
00082 #else
00083 #if defined(MBEDTLS_SSL_PROTO_TLS1_1)
00084 #define MBEDTLS_SSL_MAX_MINOR_VERSION           MBEDTLS_SSL_MINOR_VERSION_2
00085 #else
00086 #if defined(MBEDTLS_SSL_PROTO_TLS1)
00087 #define MBEDTLS_SSL_MAX_MINOR_VERSION           MBEDTLS_SSL_MINOR_VERSION_1
00088 #else
00089 #if defined(MBEDTLS_SSL_PROTO_SSL3)
00090 #define MBEDTLS_SSL_MAX_MINOR_VERSION           MBEDTLS_SSL_MINOR_VERSION_0
00091 #endif /* MBEDTLS_SSL_PROTO_SSL3   */
00092 #endif /* MBEDTLS_SSL_PROTO_TLS1   */
00093 #endif /* MBEDTLS_SSL_PROTO_TLS1_1 */
00094 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
00095 
00096 #define MBEDTLS_SSL_INITIAL_HANDSHAKE           0
00097 #define MBEDTLS_SSL_RENEGOTIATION_IN_PROGRESS   1   /* In progress */
00098 #define MBEDTLS_SSL_RENEGOTIATION_DONE          2   /* Done or aborted */
00099 #define MBEDTLS_SSL_RENEGOTIATION_PENDING       3   /* Requested (server only) */
00100 
00101 /*
00102  * DTLS retransmission states, see RFC 6347 4.2.4
00103  *
00104  * The SENDING state is merged in PREPARING for initial sends,
00105  * but is distinct for resends.
00106  *
00107  * Note: initial state is wrong for server, but is not used anyway.
00108  */
00109 #define MBEDTLS_SSL_RETRANS_PREPARING       0
00110 #define MBEDTLS_SSL_RETRANS_SENDING         1
00111 #define MBEDTLS_SSL_RETRANS_WAITING         2
00112 #define MBEDTLS_SSL_RETRANS_FINISHED        3
00113 
00114 /*
00115  * Allow extra bytes for record, authentication and encryption overhead:
00116  * counter (8) + header (5) + IV(16) + MAC (16-48) + padding (0-256)
00117  * and allow for a maximum of 1024 of compression expansion if
00118  * enabled.
00119  */
00120 #if defined(MBEDTLS_ZLIB_SUPPORT)
00121 #define MBEDTLS_SSL_COMPRESSION_ADD          1024
00122 #else
00123 #define MBEDTLS_SSL_COMPRESSION_ADD             0
00124 #endif
00125 
00126 #if defined(MBEDTLS_ARC4_C) || defined(MBEDTLS_CIPHER_MODE_CBC)
00127 /* Ciphersuites using HMAC */
00128 #if defined(MBEDTLS_SHA512_C)
00129 #define MBEDTLS_SSL_MAC_ADD                 48  /* SHA-384 used for HMAC */
00130 #elif defined(MBEDTLS_SHA256_C)
00131 #define MBEDTLS_SSL_MAC_ADD                 32  /* SHA-256 used for HMAC */
00132 #else
00133 #define MBEDTLS_SSL_MAC_ADD                 20  /* SHA-1   used for HMAC */
00134 #endif
00135 #else
00136 /* AEAD ciphersuites: GCM and CCM use a 128 bits tag */
00137 #define MBEDTLS_SSL_MAC_ADD                 16
00138 #endif
00139 
00140 #if defined(MBEDTLS_CIPHER_MODE_CBC)
00141 #define MBEDTLS_SSL_PADDING_ADD            256
00142 #else
00143 #define MBEDTLS_SSL_PADDING_ADD              0
00144 #endif
00145 
00146 #define MBEDTLS_SSL_PAYLOAD_LEN ( MBEDTLS_SSL_MAX_CONTENT_LEN    \
00147                         + MBEDTLS_SSL_COMPRESSION_ADD            \
00148                         + MBEDTLS_MAX_IV_LENGTH                  \
00149                         + MBEDTLS_SSL_MAC_ADD                    \
00150                         + MBEDTLS_SSL_PADDING_ADD                \
00151                         )
00152 
00153 /*
00154  * Check that we obey the standard's message size bounds
00155  */
00156 
00157 #if MBEDTLS_SSL_MAX_CONTENT_LEN > 16384
00158 #error Bad configuration - record content too large.
00159 #endif
00160 
00161 #if MBEDTLS_SSL_PAYLOAD_LEN > 16384 + 2048
00162 #error Bad configuration - protected record payload too large.
00163 #endif
00164 
00165 /* Note: Even though the TLS record header is only 5 bytes
00166    long, we're internally using 8 bytes to store the
00167    implicit sequence number. */
00168 #define MBEDTLS_SSL_HEADER_LEN 13
00169 
00170 #define MBEDTLS_SSL_BUFFER_LEN  \
00171     ( ( MBEDTLS_SSL_HEADER_LEN ) + ( MBEDTLS_SSL_PAYLOAD_LEN ) )
00172 
00173 /*
00174  * TLS extension flags (for extensions with outgoing ServerHello content
00175  * that need it (e.g. for RENEGOTIATION_INFO the server already knows because
00176  * of state of the renegotiation flag, so no indicator is required)
00177  */
00178 #define MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS_PRESENT (1 << 0)
00179 #define MBEDTLS_TLS_EXT_ECJPAKE_KKPP_OK                 (1 << 1)
00180 
00181 #ifdef __cplusplus
00182 extern "C" {
00183 #endif
00184 
00185 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
00186     defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
00187 /*
00188  * Abstraction for a grid of allowed signature-hash-algorithm pairs.
00189  */
00190 struct mbedtls_ssl_sig_hash_set_t
00191 {
00192     /* At the moment, we only need to remember a single suitable
00193      * hash algorithm per signature algorithm. As long as that's
00194      * the case - and we don't need a general lookup function -
00195      * we can implement the sig-hash-set as a map from signatures
00196      * to hash algorithms. */
00197     mbedtls_md_type_t rsa;
00198     mbedtls_md_type_t ecdsa;
00199 };
00200 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 &&
00201           MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED */
00202 
00203 /*
00204  * This structure contains the parameters only needed during handshake.
00205  */
00206 struct mbedtls_ssl_handshake_params
00207 {
00208     /*
00209      * Handshake specific crypto variables
00210      */
00211 
00212 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
00213     defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
00214     mbedtls_ssl_sig_hash_set_t hash_algs;             /*!<  Set of suitable sig-hash pairs */
00215 #endif
00216 #if defined(MBEDTLS_DHM_C)
00217     mbedtls_dhm_context dhm_ctx;                /*!<  DHM key exchange        */
00218 #endif
00219 #if defined(MBEDTLS_ECDH_C)
00220     mbedtls_ecdh_context ecdh_ctx;              /*!<  ECDH key exchange       */
00221 #endif
00222 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
00223     mbedtls_ecjpake_context ecjpake_ctx;        /*!< EC J-PAKE key exchange */
00224 #if defined(MBEDTLS_SSL_CLI_C)
00225     unsigned char *ecjpake_cache;               /*!< Cache for ClientHello ext */
00226     size_t ecjpake_cache_len;                   /*!< Length of cached data */
00227 #endif
00228 #endif /* MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
00229 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
00230     defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
00231     const mbedtls_ecp_curve_info **curves;      /*!<  Supported elliptic curves */
00232 #endif
00233 #if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
00234     unsigned char *psk;                 /*!<  PSK from the callback         */
00235     size_t psk_len;                     /*!<  Length of PSK from callback   */
00236 #endif
00237 #if defined(MBEDTLS_X509_CRT_PARSE_C)
00238     mbedtls_ssl_key_cert *key_cert;     /*!< chosen key/cert pair (server)  */
00239 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
00240     int sni_authmode;                   /*!< authmode from SNI callback     */
00241     mbedtls_ssl_key_cert *sni_key_cert; /*!< key/cert list from SNI         */
00242     mbedtls_x509_crt *sni_ca_chain;     /*!< trusted CAs from SNI callback  */
00243     mbedtls_x509_crl *sni_ca_crl;       /*!< trusted CAs CRLs from SNI      */
00244 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
00245 #endif /* MBEDTLS_X509_CRT_PARSE_C */
00246 #if defined(MBEDTLS_SSL_PROTO_DTLS)
00247     unsigned int out_msg_seq;           /*!<  Outgoing handshake sequence number */
00248     unsigned int in_msg_seq;            /*!<  Incoming handshake sequence number */
00249 
00250     unsigned char *verify_cookie;       /*!<  Cli: HelloVerifyRequest cookie
00251                                               Srv: unused                    */
00252     unsigned char verify_cookie_len;    /*!<  Cli: cookie length
00253                                               Srv: flag for sending a cookie */
00254 
00255     unsigned char *hs_msg;              /*!<  Reassembled handshake message  */
00256 
00257     uint32_t retransmit_timeout;        /*!<  Current value of timeout       */
00258     unsigned char retransmit_state;     /*!<  Retransmission state           */
00259     mbedtls_ssl_flight_item *flight;            /*!<  Current outgoing flight        */
00260     mbedtls_ssl_flight_item *cur_msg;           /*!<  Current message in flight      */
00261     unsigned int in_flight_start_seq;   /*!<  Minimum message sequence in the
00262                                               flight being received          */
00263     mbedtls_ssl_transform *alt_transform_out;   /*!<  Alternative transform for
00264                                               resending messages             */
00265     unsigned char alt_out_ctr[8];       /*!<  Alternative record epoch/counter
00266                                               for resending messages         */
00267 #endif /* MBEDTLS_SSL_PROTO_DTLS */
00268 
00269     /*
00270      * Checksum contexts
00271      */
00272 #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
00273     defined(MBEDTLS_SSL_PROTO_TLS1_1)
00274        mbedtls_md5_context fin_md5;
00275       mbedtls_sha1_context fin_sha1;
00276 #endif
00277 #if defined(MBEDTLS_SSL_PROTO_TLS1_2)
00278 #if defined(MBEDTLS_SHA256_C)
00279     mbedtls_sha256_context fin_sha256;
00280 #endif
00281 #if defined(MBEDTLS_SHA512_C)
00282     mbedtls_sha512_context fin_sha512;
00283 #endif
00284 #endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
00285 
00286     void (*update_checksum)(mbedtls_ssl_context *, const unsigned char *, size_t);
00287     void (*calc_verify)(mbedtls_ssl_context *, unsigned char *);
00288     void (*calc_finished)(mbedtls_ssl_context *, unsigned char *, int);
00289     int  (*tls_prf)(const unsigned char *, size_t, const char *,
00290                     const unsigned char *, size_t,
00291                     unsigned char *, size_t);
00292 
00293     size_t pmslen;                      /*!<  premaster length        */
00294 
00295     unsigned char randbytes[64];        /*!<  random bytes            */
00296     unsigned char premaster[MBEDTLS_PREMASTER_SIZE];
00297                                         /*!<  premaster secret        */
00298 
00299     int resume;                         /*!<  session resume indicator*/
00300     int max_major_ver;                  /*!< max. major version client*/
00301     int max_minor_ver;                  /*!< max. minor version client*/
00302     int cli_exts;                       /*!< client extension presence*/
00303 
00304 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
00305     int new_session_ticket;             /*!< use NewSessionTicket?    */
00306 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
00307 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
00308     int extended_ms;                    /*!< use Extended Master Secret? */
00309 #endif
00310 };
00311 
00312 /*
00313  * This structure contains a full set of runtime transform parameters
00314  * either in negotiation or active.
00315  */
00316 struct mbedtls_ssl_transform
00317 {
00318     /*
00319      * Session specific crypto layer
00320      */
00321     const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
00322                                         /*!<  Chosen cipersuite_info  */
00323     unsigned int keylen;                /*!<  symmetric key length (bytes)  */
00324     size_t minlen;                      /*!<  min. ciphertext length  */
00325     size_t ivlen;                       /*!<  IV length               */
00326     size_t fixed_ivlen;                 /*!<  Fixed part of IV (AEAD) */
00327     size_t maclen;                      /*!<  MAC length              */
00328 
00329     unsigned char iv_enc[16];           /*!<  IV (encryption)         */
00330     unsigned char iv_dec[16];           /*!<  IV (decryption)         */
00331 
00332 #if defined(MBEDTLS_SSL_PROTO_SSL3)
00333     /* Needed only for SSL v3.0 secret */
00334     unsigned char mac_enc[20];          /*!<  SSL v3.0 secret (enc)   */
00335     unsigned char mac_dec[20];          /*!<  SSL v3.0 secret (dec)   */
00336 #endif /* MBEDTLS_SSL_PROTO_SSL3 */
00337 
00338     mbedtls_md_context_t md_ctx_enc;            /*!<  MAC (encryption)        */
00339     mbedtls_md_context_t md_ctx_dec;            /*!<  MAC (decryption)        */
00340 
00341     mbedtls_cipher_context_t cipher_ctx_enc;    /*!<  encryption context      */
00342     mbedtls_cipher_context_t cipher_ctx_dec;    /*!<  decryption context      */
00343 
00344     /*
00345      * Session specific compression layer
00346      */
00347 #if defined(MBEDTLS_ZLIB_SUPPORT)
00348     z_stream ctx_deflate;               /*!<  compression context     */
00349     z_stream ctx_inflate;               /*!<  decompression context   */
00350 #endif
00351 };
00352 
00353 #if defined(MBEDTLS_X509_CRT_PARSE_C)
00354 /*
00355  * List of certificate + private key pairs
00356  */
00357 struct mbedtls_ssl_key_cert
00358 {
00359     mbedtls_x509_crt *cert;                 /*!< cert                       */
00360     mbedtls_pk_context *key;                /*!< private key                */
00361     mbedtls_ssl_key_cert *next;             /*!< next key/cert pair         */
00362 };
00363 #endif /* MBEDTLS_X509_CRT_PARSE_C */
00364 
00365 #if defined(MBEDTLS_SSL_PROTO_DTLS)
00366 /*
00367  * List of handshake messages kept around for resending
00368  */
00369 struct mbedtls_ssl_flight_item
00370 {
00371     unsigned char *p;       /*!< message, including handshake headers   */
00372     size_t len;             /*!< length of p                            */
00373     unsigned char type;     /*!< type of the message: handshake or CCS  */
00374     mbedtls_ssl_flight_item *next;  /*!< next handshake message(s)              */
00375 };
00376 #endif /* MBEDTLS_SSL_PROTO_DTLS */
00377 
00378 #if defined(MBEDTLS_SSL_PROTO_TLS1_2) && \
00379     defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
00380 
00381 /* Find an entry in a signature-hash set matching a given hash algorithm. */
00382 mbedtls_md_type_t mbedtls_ssl_sig_hash_set_find( mbedtls_ssl_sig_hash_set_t *set,
00383                                                  mbedtls_pk_type_t sig_alg );
00384 /* Add a signature-hash-pair to a signature-hash set */
00385 void mbedtls_ssl_sig_hash_set_add( mbedtls_ssl_sig_hash_set_t *set,
00386                                    mbedtls_pk_type_t sig_alg,
00387                                    mbedtls_md_type_t md_alg );
00388 /* Allow exactly one hash algorithm for each signature. */
00389 void mbedtls_ssl_sig_hash_set_const_hash( mbedtls_ssl_sig_hash_set_t *set,
00390                                           mbedtls_md_type_t md_alg );
00391 
00392 /* Setup an empty signature-hash set */
00393 static inline void mbedtls_ssl_sig_hash_set_init( mbedtls_ssl_sig_hash_set_t *set )
00394 {
00395     mbedtls_ssl_sig_hash_set_const_hash( set, MBEDTLS_MD_NONE );
00396 }
00397 
00398 #endif /* MBEDTLS_SSL_PROTO_TLS1_2) &&
00399           MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED */
00400 
00401 /**
00402  * \brief           Free referenced items in an SSL transform context and clear
00403  *                  memory
00404  *
00405  * \param transform SSL transform context
00406  */
00407 void mbedtls_ssl_transform_free( mbedtls_ssl_transform *transform );
00408 
00409 /**
00410  * \brief           Free referenced items in an SSL handshake context and clear
00411  *                  memory
00412  *
00413  * \param handshake SSL handshake context
00414  */
00415 void mbedtls_ssl_handshake_free( mbedtls_ssl_handshake_params *handshake );
00416 
00417 int mbedtls_ssl_handshake_client_step( mbedtls_ssl_context *ssl );
00418 int mbedtls_ssl_handshake_server_step( mbedtls_ssl_context *ssl );
00419 void mbedtls_ssl_handshake_wrapup( mbedtls_ssl_context *ssl );
00420 
00421 int mbedtls_ssl_send_fatal_handshake_failure( mbedtls_ssl_context *ssl );
00422 
00423 void mbedtls_ssl_reset_checksum( mbedtls_ssl_context *ssl );
00424 int mbedtls_ssl_derive_keys( mbedtls_ssl_context *ssl );
00425 
00426 int mbedtls_ssl_read_record_layer( mbedtls_ssl_context *ssl );
00427 int mbedtls_ssl_handle_message_type( mbedtls_ssl_context *ssl );
00428 int mbedtls_ssl_prepare_handshake_record( mbedtls_ssl_context *ssl );
00429 void mbedtls_ssl_update_handshake_status( mbedtls_ssl_context *ssl );
00430 
00431 /**
00432  * \brief       Update record layer
00433  *
00434  *              This function roughly separates the implementation
00435  *              of the logic of (D)TLS from the implementation
00436  *              of the secure transport.
00437  *
00438  * \param  ssl  SSL context to use
00439  *
00440  * \return      0 or non-zero error code.
00441  *
00442  * \note        A clarification on what is called 'record layer' here
00443  *              is in order, as many sensible definitions are possible:
00444  *
00445  *              The record layer takes as input an untrusted underlying
00446  *              transport (stream or datagram) and transforms it into
00447  *              a serially multiplexed, secure transport, which
00448  *              conceptually provides the following:
00449  *
00450  *              (1) Three datagram based, content-agnostic transports
00451  *                  for handshake, alert and CCS messages.
00452  *              (2) One stream- or datagram-based transport
00453  *                  for application data.
00454  *              (3) Functionality for changing the underlying transform
00455  *                  securing the contents.
00456  *
00457  *              The interface to this functionality is given as follows:
00458  *
00459  *              a Updating
00460  *                [Currently implemented by mbedtls_ssl_read_record]
00461  *
00462  *                Check if and on which of the four 'ports' data is pending:
00463  *                Nothing, a controlling datagram of type (1), or application
00464  *                data (2). In any case data is present, internal buffers
00465  *                provide access to the data for the user to process it.
00466  *                Consumption of type (1) datagrams is done automatically
00467  *                on the next update, invalidating that the internal buffers
00468  *                for previous datagrams, while consumption of application
00469  *                data (2) is user-controlled.
00470  *
00471  *              b Reading of application data
00472  *                [Currently manual adaption of ssl->in_offt pointer]
00473  *
00474  *                As mentioned in the last paragraph, consumption of data
00475  *                is different from the automatic consumption of control
00476  *                datagrams (1) because application data is treated as a stream.
00477  *
00478  *              c Tracking availability of application data
00479  *                [Currently manually through decreasing ssl->in_msglen]
00480  *
00481  *                For efficiency and to retain datagram semantics for
00482  *                application data in case of DTLS, the record layer
00483  *                provides functionality for checking how much application
00484  *                data is still available in the internal buffer.
00485  *
00486  *              d Changing the transformation securing the communication.
00487  *
00488  *              Given an opaque implementation of the record layer in the
00489  *              above sense, it should be possible to implement the logic
00490  *              of (D)TLS on top of it without the need to know anything
00491  *              about the record layer's internals. This is done e.g.
00492  *              in all the handshake handling functions, and in the
00493  *              application data reading function mbedtls_ssl_read.
00494  *
00495  * \note        The above tries to give a conceptual picture of the
00496  *              record layer, but the current implementation deviates
00497  *              from it in some places. For example, our implementation of
00498  *              the update functionality through mbedtls_ssl_read_record
00499  *              discards datagrams depending on the current state, which
00500  *              wouldn't fall under the record layer's responsibility
00501  *              following the above definition.
00502  *
00503  */
00504 int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl );
00505 int mbedtls_ssl_fetch_input( mbedtls_ssl_context *ssl, size_t nb_want );
00506 
00507 int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl );
00508 int mbedtls_ssl_flush_output( mbedtls_ssl_context *ssl );
00509 
00510 int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl );
00511 int mbedtls_ssl_write_certificate( mbedtls_ssl_context *ssl );
00512 
00513 int mbedtls_ssl_parse_change_cipher_spec( mbedtls_ssl_context *ssl );
00514 int mbedtls_ssl_write_change_cipher_spec( mbedtls_ssl_context *ssl );
00515 
00516 int mbedtls_ssl_parse_finished( mbedtls_ssl_context *ssl );
00517 int mbedtls_ssl_write_finished( mbedtls_ssl_context *ssl );
00518 
00519 void mbedtls_ssl_optimize_checksum( mbedtls_ssl_context *ssl,
00520                             const mbedtls_ssl_ciphersuite_t *ciphersuite_info );
00521 
00522 #if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
00523 int mbedtls_ssl_psk_derive_premaster( mbedtls_ssl_context *ssl, mbedtls_key_exchange_type_t key_ex );
00524 #endif
00525 
00526 #if defined(MBEDTLS_PK_C)
00527 unsigned char mbedtls_ssl_sig_from_pk( mbedtls_pk_context *pk );
00528 unsigned char mbedtls_ssl_sig_from_pk_alg( mbedtls_pk_type_t type );
00529 mbedtls_pk_type_t mbedtls_ssl_pk_alg_from_sig( unsigned char sig );
00530 #endif
00531 
00532 mbedtls_md_type_t mbedtls_ssl_md_alg_from_hash( unsigned char hash );
00533 unsigned char mbedtls_ssl_hash_from_md_alg( int md );
00534 int mbedtls_ssl_set_calc_verify_md( mbedtls_ssl_context *ssl, int md );
00535 
00536 #if defined(MBEDTLS_ECP_C)
00537 int mbedtls_ssl_check_curve( const mbedtls_ssl_context *ssl, mbedtls_ecp_group_id grp_id );
00538 #endif
00539 
00540 #if defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
00541 int mbedtls_ssl_check_sig_hash( const mbedtls_ssl_context *ssl,
00542                                 mbedtls_md_type_t md );
00543 #endif
00544 
00545 #if defined(MBEDTLS_X509_CRT_PARSE_C)
00546 static inline mbedtls_pk_context *mbedtls_ssl_own_key( mbedtls_ssl_context *ssl )
00547 {
00548     mbedtls_ssl_key_cert *key_cert;
00549 
00550     if( ssl->handshake != NULL && ssl->handshake->key_cert != NULL )
00551         key_cert = ssl->handshake->key_cert;
00552     else
00553         key_cert = ssl->conf->key_cert;
00554 
00555     return( key_cert == NULL ? NULL : key_cert->key );
00556 }
00557 
00558 static inline mbedtls_x509_crt *mbedtls_ssl_own_cert( mbedtls_ssl_context *ssl )
00559 {
00560     mbedtls_ssl_key_cert *key_cert;
00561 
00562     if( ssl->handshake != NULL && ssl->handshake->key_cert != NULL )
00563         key_cert = ssl->handshake->key_cert;
00564     else
00565         key_cert = ssl->conf->key_cert;
00566 
00567     return( key_cert == NULL ? NULL : key_cert->cert );
00568 }
00569 
00570 /*
00571  * Check usage of a certificate wrt extensions:
00572  * keyUsage, extendedKeyUsage (later), and nSCertType (later).
00573  *
00574  * Warning: cert_endpoint is the endpoint of the cert (ie, of our peer when we
00575  * check a cert we received from them)!
00576  *
00577  * Return 0 if everything is OK, -1 if not.
00578  */
00579 int mbedtls_ssl_check_cert_usage( const mbedtls_x509_crt *cert,
00580                           const mbedtls_ssl_ciphersuite_t *ciphersuite,
00581                           int cert_endpoint,
00582                           uint32_t *flags );
00583 #endif /* MBEDTLS_X509_CRT_PARSE_C */
00584 
00585 void mbedtls_ssl_write_version( int major, int minor, int transport,
00586                         unsigned char ver[2] );
00587 void mbedtls_ssl_read_version( int *major, int *minor, int transport,
00588                        const unsigned char ver[2] );
00589 
00590 static inline size_t mbedtls_ssl_hdr_len( const mbedtls_ssl_context *ssl )
00591 {
00592 #if defined(MBEDTLS_SSL_PROTO_DTLS)
00593     if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
00594         return( 13 );
00595 #else
00596     ((void) ssl);
00597 #endif
00598     return( 5 );
00599 }
00600 
00601 static inline size_t mbedtls_ssl_hs_hdr_len( const mbedtls_ssl_context *ssl )
00602 {
00603 #if defined(MBEDTLS_SSL_PROTO_DTLS)
00604     if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
00605         return( 12 );
00606 #else
00607     ((void) ssl);
00608 #endif
00609     return( 4 );
00610 }
00611 
00612 #if defined(MBEDTLS_SSL_PROTO_DTLS)
00613 void mbedtls_ssl_send_flight_completed( mbedtls_ssl_context *ssl );
00614 void mbedtls_ssl_recv_flight_completed( mbedtls_ssl_context *ssl );
00615 int mbedtls_ssl_resend( mbedtls_ssl_context *ssl );
00616 #endif
00617 
00618 /* Visible for testing purposes only */
00619 #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
00620 int mbedtls_ssl_dtls_replay_check( mbedtls_ssl_context *ssl );
00621 void mbedtls_ssl_dtls_replay_update( mbedtls_ssl_context *ssl );
00622 #endif
00623 
00624 /* constant-time buffer comparison */
00625 static inline int mbedtls_ssl_safer_memcmp( const void *a, const void *b, size_t n )
00626 {
00627     size_t i;
00628     volatile const unsigned char *A = (volatile const unsigned char *) a;
00629     volatile const unsigned char *B = (volatile const unsigned char *) b;
00630     volatile unsigned char diff = 0;
00631 
00632     for( i = 0; i < n; i++ )
00633         diff |= A[i] ^ B[i];
00634 
00635     return( diff );
00636 }
00637 
00638 #if defined(MBEDTLS_SSL_PROTO_SSL3) || defined(MBEDTLS_SSL_PROTO_TLS1) || \
00639     defined(MBEDTLS_SSL_PROTO_TLS1_1)
00640 int mbedtls_ssl_get_key_exchange_md_ssl_tls( mbedtls_ssl_context *ssl,
00641                                         unsigned char *output,
00642                                         unsigned char *data, size_t data_len );
00643 #endif /* MBEDTLS_SSL_PROTO_SSL3 || MBEDTLS_SSL_PROTO_TLS1 || \
00644           MBEDTLS_SSL_PROTO_TLS1_1 */
00645 
00646 #if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
00647     defined(MBEDTLS_SSL_PROTO_TLS1_2)
00648 int mbedtls_ssl_get_key_exchange_md_tls1_2( mbedtls_ssl_context *ssl,
00649                                         unsigned char *output,
00650                                         unsigned char *data, size_t data_len,
00651                                         mbedtls_md_type_t md_alg );
00652 #endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \
00653           MBEDTLS_SSL_PROTO_TLS1_2 */
00654 
00655 #ifdef __cplusplus
00656 }
00657 #endif
00658 
00659 #endif /* ssl_internal.h */