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started integrating bearssl, wrote SSL profile that only incorporates safe TLS1.2 ciphers

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Noah Laptop 2019-02-20 16:58:26 -08:00
parent 32fa4ac11d
commit 0d424049f0
3 changed files with 467 additions and 5 deletions
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7
src/SSLClient.h
View file

@ -100,8 +100,13 @@ public:
C& getClient() { return m_client; }
private:
// create a copy of the class
// create a copy of the client
C m_client;
// store the context values required for SSL
br_ssl_client_context m_sslctx;
br_x509_minimal_context m_x509ctx;
unsigned char m_iobuf[BR_SSL_BUFSIZE_MONO];
br_sslio_context m_ioctx;
};
#endif /** SSLClient_H_ */

459
src/bearssl/TLS12_only_profile.c Normal file
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@ -0,0 +1,459 @@
/*
* Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "bearssl.h"
/*
* A "profile" is an initialisation function for a SSL context, that
* configures a list of cipher suites and algorithm implementations.
* While BearSSL comes with a few predefined profiles, you might one
* to define you own, using the example below as guidance.
*
* Each individual initialisation call sets a parameter or an algorithm
* support. Setting a specific algorithm pulls in the implementation of
* that algorithm in the compiled binary, as per static linking
* behaviour. Removing some of this calls will then reduce total code
* footprint, but also mechanically prevents some features to be
* supported (protocol versions and cipher suites).
*
* The two below define profiles for the client and the server contexts,
* respectively. Of course, in a typical size-constrained application,
* you would use one or the other, not both, to avoid pulling in code
* for both.
*
* This profile has been modified to the following criteria
* * support only TLS 1.2 for security
* * Use a minimal size footprint
* * remove RSA_WITH_AES ciphers for above
*/
void
TLS12_only_profile(br_ssl_client_context *cc
br_x509_minimal_context *xc,
const br_x509_trust_anchor *trust_anchors, size_t trust_anchors_num)
{
/*
* The "full" profile supports all implemented cipher suites.
*
* Rationale for suite order, from most important to least
* important rule:
*
* -- Only support TLS 1.2
* -- Don't support RSA and 3DES as they are weaker protocols
* -- Try to have Forward Secrecy (ECDHE suite) if possible.
* -- When not using Forward Secrecy, ECDH key exchange is
* better than RSA key exchange (slightly more expensive on the
* client, but much cheaper on the server, and it implies smaller
* messages).
* -- ChaCha20+Poly1305 is better than AES/GCM (faster, smaller code).
* -- GCM is better than CBC.
* -- AES-128 is preferred over AES-256 (AES-128 is already
* strong enough, and AES-256 is 40% more expensive).
*/
static const uint16_t suites[] = {
BR_TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256,
BR_TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256,
BR_TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
BR_TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
BR_TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
BR_TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
BR_TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256,
BR_TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,
BR_TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384,
BR_TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384,
BR_TLS_ECDH_ECDSA_WITH_AES_128_GCM_SHA256,
BR_TLS_ECDH_RSA_WITH_AES_128_GCM_SHA256,
BR_TLS_ECDH_ECDSA_WITH_AES_256_GCM_SHA384,
BR_TLS_ECDH_RSA_WITH_AES_256_GCM_SHA384,
BR_TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA256,
BR_TLS_ECDH_RSA_WITH_AES_128_CBC_SHA256,
BR_TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA384,
BR_TLS_ECDH_RSA_WITH_AES_256_CBC_SHA384,
};
/*
* Client context must be cleared at some point. This sets
* every value and pointer to 0 or NULL.
*/
br_ssl_client_zero(cc);
/*
* Define minimum and maximum protocol versions. Supported
* versions are:
* BR_TLS10 TLS 1.0
* BR_TLS11 TLS 1.1
* BR_TLS12 TLS 1.2
*/
br_ssl_engine_set_versions(&cc->eng, BR_TLS12, BR_TLS12);
/*
* Set the PRF implementation(s).
* For TLS 1.0 and 1.1, the "prf10" is needed.
* For TLS 1.2, this depends on the cipher suite:
* -- cipher suites with a name ending in "SHA384" need "prf_sha384";
* -- all others need "prf_sha256".
*
* Note that a cipher suite like TLS_RSA_WITH_AES_128_CBC_SHA will
* use SHA-1 for the per-record MAC (that's what the final "SHA"
* means), but still SHA-256 for the PRF when selected along with
* the TLS-1.2 protocol version.
*/
// br_ssl_engine_set_prf10(&cc->eng, &br_tls10_prf);
br_ssl_engine_set_prf_sha256(&cc->eng, &br_tls12_sha256_prf);
br_ssl_engine_set_prf_sha384(&cc->eng, &br_tls12_sha384_prf);
/*
* Set hash functions for the engine. Required hash functions
* depend on the protocol and cipher suite:
*
* -- TLS 1.0 and 1.1 require both MD5 and SHA-1.
* -- With TLS 1.2, cipher suites with a name ending in "SHA384"
* require SHA-384.
* -- With TLS 1.2, cipher suites with a name ending in "SHA256"
* require SHA-256.
* -- With TLS 1.2, cipher suites with a name ending in "SHA"
* require both SHA-256 and SHA-1.
*
* Moreover, these hash functions are also used to compute
* hashes supporting signatures on the server side (for ECDHE_*
* cipher suites), and on the client side (for client
* certificates, except in the case of full static ECDH). In TLS
* 1.0 and 1.1, SHA-1 (and also MD5) will be used, but with TLS
* 1.2 these hash functions are negotiated between client and
* server; SHA-256 and/or SHA-384 should be sufficient in
* practice.
*
* Note that with current implementations, SHA-224 and SHA-256
* share the same file, so if you use one, you may have the other
* one with no additional overhead. Similarly, SHA-384 and SHA-512
* share the same implementation code.
*/
// br_ssl_engine_set_hash(&cc->eng, br_md5_ID, &br_md5_vtable);
// br_ssl_engine_set_hash(&cc->eng, br_sha1_ID, &br_sha1_vtable);
br_ssl_engine_set_hash(&cc->eng, br_sha224_ID, &br_sha224_vtable);
br_ssl_engine_set_hash(&cc->eng, br_sha256_ID, &br_sha256_vtable);
br_ssl_engine_set_hash(&cc->eng, br_sha384_ID, &br_sha384_vtable);
// br_ssl_engine_set_hash(&cc->eng, br_sha512_ID, &br_sha512_vtable);
/*
* Set the cipher suites. All specified cipher suite MUST be
* supported, and the relevant algorithms MUST have been
* configured (failure to provide needed implementations may
* trigger unwanted behaviours like segfaults or overflows).
*/
br_ssl_engine_set_suites(&cc->eng, suites,
(sizeof suites) / (sizeof suites[0]));
/*
* Public-key algorithm implementations.
*
* -- RSA public core ("rsapub") is needed for "RSA" key exchange
* (cipher suites whose name starts with TLS_RSA).
*
* -- RSA signature verification ("rsavrfy") is needed for
* "ECDHE_RSA" cipher suites (not ECDH_RSA).
*
* -- Elliptic curve implementation ("ec") is needed for cipher
* suites that use elliptic curves (both "ECDH" and "ECDHE"
* cipher suites).
*
* -- ECDSA signature verification is needed for "ECDHE_ECDSA"
* cipher suites (but not for ECDHE_RSA, ECDH_ECDSA or ECDH_RSA).
*
* Normally, you use the "default" implementations, obtained
* through relevant function calls. These functions return
* implementations that are deemed "best" for the current
* platform, where "best" means "fastest within constant-time
* implementations". Selecting the default implementation is a
* mixture of compile-time and runtime checks.
*
* Nevertheless, specific implementations may be selected
* explicitly, e.g. to use code which is slower but with a
* smaller footprint.
*
* The RSA code comes in three variants, called "i15", "i31" and
* "i32". The "i31" code is somewhat faster than the "i32" code.
* Usually, "i31" is faster than "i15", except on some specific
* architectures (ARM Cortex M0, M0+, M1 and M3) where the "i15"
* should be preferred (the "i15" code is constant-time, while
* the "i31" is not, and the "i15" code is faster anyway).
*
* ECDSA code also comes in "i15" and "i31" variants. As in the
* case of RSA, the "i31" code is faster, except on the small
* ARM Cortex M, where the "i15" code is faster and safer.
*
* There are no less than 10 elliptic curve implementations:
*
* - ec_c25519_i15, ec_c25519_i31, ec_c25519_m15 and ec_c25519_m31
* implement Curve25519.
*
* - ec_p256_m15 and ec_p256_m31 implement NIST curve P-256.
*
* - ec_prime_i15 and ec_prime_i31 implement NIST curves P-256,
* P-384 and P-521.
*
* - ec_all_m15 is an aggregate implementation that uses
* ec_c25519_m15, ec_p256_m15 and ec_prime_i15.
*
* - ec_all_m31 is an aggregate implementation that uses
* ec_c25519_m31, ec_p256_m31 and ec_prime_i31.
*
* For a given curve, "m15" is faster than "i15" (but possibly
* with a larger code footprint) and "m31" is faster than "i31"
* (there again with a larger code footprint). For best
* performance, use ec_all_m31, except on the small ARM Cortex M
* where ec_all_m15 should be used. Referencing the other
* implementations directly will result in smaller code, but
* support for fewer curves and possibly lower performance.
*/
// br_ssl_client_set_default_rsapub(cc);
// br_ssl_engine_set_default_rsavrfy(&cc->eng);
// br_ssl_engine_set_default_ecdsa(&cc->eng);
//* Alternate: set implementations explicitly.
// br_ssl_client_set_rsapub(cc, &br_rsa_i31_public);
br_ssl_client_set_rsavrfy(cc, &br_rsa_i15_pkcs1_vrfy);
br_ssl_engine_set_ec(&cc->eng, &br_ec_all_m15);
br_ssl_engine_set_ecdsa(&cc->eng, &br_ecdsa_i15_vrfy_asn1);
//*/
/*
* Record handler:
* -- Cipher suites in AES_128_CBC, AES_256_CBC and 3DES_EDE_CBC
* need the CBC record handler ("set_cbc").
* -- Cipher suites in AES_128_GCM and AES_256_GCM need the GCM
* record handler ("set_gcm").
* -- Cipher suites in CHACHA20_POLY1305 need the ChaCha20+Poly1305
* record handler ("set_chapol").
*/
br_ssl_engine_set_cbc(&cc->eng,
&br_sslrec_in_cbc_vtable,
&br_sslrec_out_cbc_vtable);
br_ssl_engine_set_gcm(&cc->eng,
&br_sslrec_in_gcm_vtable,
&br_sslrec_out_gcm_vtable);
// br_ssl_engine_set_chapol(&cc->eng,
// &br_sslrec_in_chapol_vtable,
// &br_sslrec_out_chapol_vtable);
/*
* Set the ChaCha20 and Poly1305 implementations
* Not included in this file orignally for some reason
*/
br_ssl_engine_set_default_chapol(&cc->eng);
/*
* Symmetric encryption:
* -- AES_128_CBC and AES_256_CBC require an "aes_cbc" implementation
* (actually two implementations, for encryption and decryption).
* -- 3DES_EDE_CBC requires a "des_cbc" implementation
* (actually two implementations, for encryption and decryption).
* -- AES_128_GCM and AES_256_GCM require an "aes_ctr" imeplementation
* and also a GHASH implementation.
*
* Two 3DES implementations are provided:
*
* des_tab Classical table-based implementation; it is
* not constant-time.
*
* dest_ct Constant-time DES/3DES implementation. It is
* slower than des_tab.
*
* Four AES implementations are provided:
*
* aes_ct Constant-time AES implementation, for 32-bit
* systems.
*
* aes_ct64 Constant-time AES implementation, for 64-bit
* systems. It actually also runs on 32-bit systems,
* but, on such systems, it yields larger code and
* slightly worse performance. On 64-bit systems,
* aes_ct64 is about twice faster than aes_ct for
* CTR processing (GCM encryption and decryption),
* and for CBC (decryption only).
*
* aes_small Smallest implementation provided, but also the
* slowest, and it is not constant-time. Use it
* only if desperate for code size.
*
* aes_big Classical table-based AES implementation. This
* is decently fast and still resonably compact,
* but it is not constant-time.
*
* aes_x86ni Very fast implementation that uses the AES-NI
* opcodes on recent x86 CPU. But it may not be
* compiled in the library if the compiler or
* architecture is not supported; and the CPU
* may also not support the opcodes. Selection
* functions are provided to test for availability
* of the code and the opcodes.
*
* Whether having constant-time implementations is absolutely
* required for security depends on the context (in particular
* whether the target architecture actually has cache memory),
* and while side-channel analysis for non-constant-time AES
* code has been demonstrated in lab conditions, it certainly
* does not apply to all actual usages, and it has never been
* spotted in the wild. It is still considered cautious to use
* constant-time code by default, and to consider the other
* implementations only if duly measured performance issues make
* it mandatory.
*/
br_ssl_engine_set_aes_cbc(&cc->eng,
&br_aes_ct_cbcenc_vtable,
&br_aes_ct_cbcdec_vtable);
br_ssl_engine_set_aes_ctr(&cc->eng,
&br_aes_ct_ctr_vtable);
/* Alternate: aes_ct64
br_ssl_engine_set_aes_cbc(&cc->eng,
&br_aes_ct64_cbcenc_vtable,
&br_aes_ct64_cbcdec_vtable);
br_ssl_engine_set_aes_ctr(&cc->eng,
&br_aes_ct64_ctr_vtable);
*/
/* Alternate: aes_small
br_ssl_engine_set_aes_cbc(&cc->eng,
&br_aes_small_cbcenc_vtable,
&br_aes_small_cbcdec_vtable);
br_ssl_engine_set_aes_ctr(&cc->eng,
&br_aes_small_ctr_vtable);
*/
/* Alternate: aes_big
br_ssl_engine_set_aes_cbc(&cc->eng,
&br_aes_big_cbcenc_vtable,
&br_aes_big_cbcdec_vtable);
br_ssl_engine_set_aes_ctr(&cc->eng,
&br_aes_big_ctr_vtable);
*/
/* 3DES Disabled
br_ssl_engine_set_des_cbc(&cc->eng,
&br_des_ct_cbcenc_vtable,
&br_des_ct_cbcdec_vtable);
*/
/* Alternate: des_tab
br_ssl_engine_set_des_cbc(&cc->eng,
&br_des_tab_cbcenc_vtable,
&br_des_tab_cbcdec_vtable);
*/
/*
* GHASH is needed for AES_128_GCM and AES_256_GCM. Three
* implementations are provided:
*
* ctmul Uses 32-bit multiplications with a 64-bit result.
*
* ctmul32 Uses 32-bit multiplications with a 32-bit result.
*
* ctmul64 Uses 64-bit multiplications with a 64-bit result.
*
* On 64-bit platforms, ctmul64 is the smallest and fastest of
* the three. On 32-bit systems, ctmul should be preferred. The
* ctmul32 implementation is meant to be used for the specific
* 32-bit systems that do not have a 32x32->64 multiplier (i.e.
* the ARM Cortex-M0 and Cortex-M0+).
*
* These implementations are all constant-time as long as the
* underlying multiplication opcode is constant-time (which is
* true for all modern systems, but not for older architectures
* such that ARM9 or 80486).
*/
/*
br_ssl_engine_set_ghash(&cc->eng,
&br_ghash_ctmul); */
//* Alternate: ghash_ctmul32
br_ssl_engine_set_ghash(&cc->eng,
&br_ghash_ctmul32);
//*/
/* Alternate: ghash_ctmul64
br_ssl_engine_set_ghash(&cc->eng,
&br_ghash_ctmul64);
*/
/*
* For a client, the normal case is to validate the server
* certificate with regards to a set of trust anchors. This
* entails using a br_x509_minimal_context structure, configured
* with the relevant algorithms, as shown below.
*
* Alternatively, the client could "know" the intended server
* public key through an out-of-band mechanism, in which case
* a br_x509_knownkey_context is appropriate, for a much reduced
* code footprint.
*
* We assume here that the following extra parameters have been
* provided:
*
* xc engine context (br_x509_minimal_context *)
* trust_anchors trust anchors (br_x509_trust_anchor *)
* trust_anchors_num number of trust anchors (size_t)
*/
/*
* The X.509 engine needs a hash function for processing the
* subject and issuer DN of certificates and trust anchors. Any
* supported hash function is appropriate; here we use SHA-256.
* The trust an
*/
br_x509_minimal_init(xc, &br_sha256_vtable,
trust_anchors, trust_anchors_num);
/*
* Set suites and asymmetric crypto implementations. We use the
* "i31" code for RSA (it is somewhat faster than the "i32"
* implementation). These implementations are used for
* signature verification on certificates, but not for the
* SSL-specific usage of the server's public key. For instance,
* if the server has an EC public key but the rest of the chain
* (intermediate CA, root...) use RSA, then you would need only
* the RSA verification function below.
*/
// br_x509_minimal_set_rsa(xc, &br_rsa_i31_pkcs1_vrfy);
br_x509_minimal_set_rsa(xc, &br_rsa_i15_pkcs1_vrfy);
// br_x509_minimal_set_ecdsa(xc,
// &br_ec_prime_i31, &br_ecdsa_i31_vrfy_asn1);
br_x509_minimal_set_ecdsa(xc,
&br_ec_all_m15, &br_ecdsa_i15_vrfy_asn1);
/*
* Set supported hash functions. These are for signatures on
* certificates. There again, you only need the hash functions
* that are actually used in certificates, but if a given
* function was included for the SSL engine, you may as well
* add it here.
*
* Note: the engine explicitly rejects signatures that use MD5.
* Thus, there is no need for MD5 here.
*/
// br_ssl_engine_set_hash(xc, br_sha1_ID, &br_sha1_vtable);
br_ssl_engine_set_hash(xc, br_sha224_ID, &br_sha224_vtable);
br_ssl_engine_set_hash(xc, br_sha256_ID, &br_sha256_vtable);
br_ssl_engine_set_hash(xc, br_sha384_ID, &br_sha384_vtable);
// br_ssl_engine_set_hash(xc, br_sha512_ID, &br_sha512_vtable);
/*
* Link the X.509 engine in the SSL engine.
*/
br_ssl_engine_set_x509(&cc->eng, &xc->vtable);
}

6
src/config.h
View file

@ -47,9 +47,8 @@
* substantially more efficient than 32-bit multiplications that yield
* 64-bit results. This is typically the case on low-end ARM Cortex M
* systems (M0, M0+, M1, and arguably M3 and M4 as well).
*
#define BR_LOMUL 1
*/
#define BR_LOMUL 1
/*
* When BR_SLOW_MUL is enabled, multiplications are assumed to be
@ -159,9 +158,8 @@
* This is meant for the low-end cores (Cortex M0, M0+, M1, M3).
* Note: if BR_LOMUL is not explicitly enabled or disabled, then
* enabling BR_ARMEL_CORTEXM_GCC also enables BR_LOMUL.
*
#define BR_ARMEL_CORTEXM_GCC 1
*/
#define BR_ARMEL_CORTEXM_GCC 1
/*
* When BR_AES_X86NI is enabled, the AES implementation using the x86 "NI"