199 lines
7.1 KiB
C
199 lines
7.1 KiB
C
/*
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* Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#include "inner.h"
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#include "time_macros.h"
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/* see bearssl_ssl.h */
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void
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br_ssl_client_init_full(br_ssl_client_context *cc,
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br_x509_minimal_context *xc,
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const br_x509_trust_anchor *trust_anchors, size_t trust_anchors_num)
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{
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/*
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* The "full" profile supports all implemented cipher suites.
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*
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* Rationale for suite order, from most important to least
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* important rule:
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*
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* -- Don't use 3DES if AES or ChaCha20 is available.
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* -- Try to have Forward Secrecy (ECDHE suite) if possible.
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* -- When not using Forward Secrecy, ECDH key exchange is
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* better than RSA key exchange (slightly more expensive on the
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* client, but much cheaper on the server, and it implies smaller
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* messages).
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* -- ChaCha20+Poly1305 is better than AES/GCM (faster, smaller code).
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* -- GCM is better than CCM and CBC. CCM is better than CBC.
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* -- CCM is preferable over CCM_8 (with CCM_8, forgeries may succeed
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* with probability 2^(-64)).
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* -- AES-128 is preferred over AES-256 (AES-128 is already
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* strong enough, and AES-256 is 40% more expensive).
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*/
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static const uint16_t suites[] = {
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BR_TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256,
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BR_TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
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BR_TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
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BR_TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
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BR_TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
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BR_TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
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BR_TLS_ECDHE_ECDSA_WITH_AES_128_CCM,
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BR_TLS_ECDHE_ECDSA_WITH_AES_256_CCM,
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BR_TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8,
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BR_TLS_ECDHE_ECDSA_WITH_AES_256_CCM_8,
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BR_TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256,
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BR_TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,
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BR_TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384,
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BR_TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384,
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BR_TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
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BR_TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
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BR_TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
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BR_TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
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BR_TLS_ECDH_ECDSA_WITH_AES_128_GCM_SHA256,
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BR_TLS_ECDH_RSA_WITH_AES_128_GCM_SHA256,
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BR_TLS_ECDH_ECDSA_WITH_AES_256_GCM_SHA384,
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BR_TLS_ECDH_RSA_WITH_AES_256_GCM_SHA384,
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BR_TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA256,
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BR_TLS_ECDH_RSA_WITH_AES_128_CBC_SHA256,
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BR_TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA384,
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BR_TLS_ECDH_RSA_WITH_AES_256_CBC_SHA384,
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BR_TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA,
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BR_TLS_ECDH_RSA_WITH_AES_128_CBC_SHA,
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BR_TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA,
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BR_TLS_ECDH_RSA_WITH_AES_256_CBC_SHA,
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BR_TLS_RSA_WITH_AES_128_GCM_SHA256,
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BR_TLS_RSA_WITH_AES_256_GCM_SHA384,
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BR_TLS_RSA_WITH_AES_128_CCM,
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BR_TLS_RSA_WITH_AES_256_CCM,
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BR_TLS_RSA_WITH_AES_128_CCM_8,
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BR_TLS_RSA_WITH_AES_256_CCM_8,
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BR_TLS_RSA_WITH_AES_128_CBC_SHA256,
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BR_TLS_RSA_WITH_AES_256_CBC_SHA256,
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BR_TLS_RSA_WITH_AES_128_CBC_SHA,
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BR_TLS_RSA_WITH_AES_256_CBC_SHA,
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BR_TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA,
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BR_TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
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BR_TLS_ECDH_ECDSA_WITH_3DES_EDE_CBC_SHA,
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BR_TLS_ECDH_RSA_WITH_3DES_EDE_CBC_SHA,
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BR_TLS_RSA_WITH_3DES_EDE_CBC_SHA
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};
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/*
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* All hash functions are activated.
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* Note: the X.509 validation engine will nonetheless refuse to
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* validate signatures that use MD5 as hash function.
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*/
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static const br_hash_class *hashes[] = {
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&br_md5_vtable,
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&br_sha1_vtable,
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&br_sha224_vtable,
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&br_sha256_vtable,
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&br_sha384_vtable,
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&br_sha512_vtable
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};
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int id;
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/*
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* Reset client context and set supported versions from TLS-1.0
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* to TLS-1.2 (inclusive).
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*/
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br_ssl_client_zero(cc);
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memset(xc, 0, sizeof *xc);
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br_ssl_engine_set_versions(&cc->eng, BR_TLS10, BR_TLS12);
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/*
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* X.509 engine uses SHA-256 to hash certificate DN (for
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* comparisons).
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*/
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br_x509_minimal_init(xc, &br_sha256_vtable,
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trust_anchors, trust_anchors_num);
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/*
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* Set suites and asymmetric crypto implementations. We use the
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* "i31" code for RSA (it is somewhat faster than the "i32"
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* implementation).
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* TODO: change that when better implementations are made available.
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*/
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br_ssl_engine_set_suites(&cc->eng, suites,
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(sizeof suites) / (sizeof suites[0]));
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br_ssl_client_set_default_rsapub(cc);
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br_ssl_engine_set_default_rsavrfy(&cc->eng);
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br_ssl_engine_set_default_ecdsa(&cc->eng);
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br_x509_minimal_set_rsa(xc, br_ssl_engine_get_rsavrfy(&cc->eng));
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br_x509_minimal_set_ecdsa(xc,
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br_ssl_engine_get_ec(&cc->eng),
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br_ssl_engine_get_ecdsa(&cc->eng));
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/*
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* Set supported hash functions, for the SSL engine and for the
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* X.509 engine.
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*/
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for (id = br_md5_ID; id <= br_sha512_ID; id ++) {
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const br_hash_class *hc;
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hc = hashes[id - 1];
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br_ssl_engine_set_hash(&cc->eng, id, hc);
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br_x509_minimal_set_hash(xc, id, hc);
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}
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/*
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* Set a fixed epoch time to validate certificates against.
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* Since we are working with an embedded device, there isn't
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* really a reliable source of time. To remedy this, we simply
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* store the time this program was compiled, and assume that
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* any certificate valid under that time is also valid at the
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* current time. This is vulnerable to the use of expired
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* certificates, however an attacker would have to use a
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* certificate valid after the compile date, which is fairly
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* difficult given the lifespan of projects here at the lab.
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* For now, this solution is good enough.
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*/
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br_x509_minimal_set_time(xc,
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// days since 1970 + days from 1970 to year 0
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(UNIX_TIMESTAMP_UTC / SEC_PER_DAY) + 719528UL,
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// seconds over start of day
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UNIX_TIMESTAMP_UTC % SEC_PER_DAY);
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/*
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* Link the X.509 engine in the SSL engine.
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*/
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br_ssl_engine_set_x509(&cc->eng, &xc->vtable);
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/*
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* Set the PRF implementations.
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*/
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br_ssl_engine_set_prf10(&cc->eng, &br_tls10_prf);
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br_ssl_engine_set_prf_sha256(&cc->eng, &br_tls12_sha256_prf);
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br_ssl_engine_set_prf_sha384(&cc->eng, &br_tls12_sha384_prf);
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/*
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* Symmetric encryption. We use the "default" implementations
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* (fastest among constant-time implementations).
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*/
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br_ssl_engine_set_default_aes_cbc(&cc->eng);
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br_ssl_engine_set_default_aes_ccm(&cc->eng);
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br_ssl_engine_set_default_aes_gcm(&cc->eng);
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br_ssl_engine_set_default_des_cbc(&cc->eng);
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br_ssl_engine_set_default_chapol(&cc->eng);
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}
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