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/* ISC license. */
#include <stdint.h>
#include <string.h>
#include <bearssl.h>
#include <skalibs/bytestr.h>
#include <skalibs/stralloc.h>
#include <skalibs/genalloc.h>
#include <skalibs/avltree.h>
#include <s6-networking/sbearssl.h>
#include "sbearssl-internal.h"
#define INSTANCE(c) ((sbearssl_sni_policy_context *)(c))
#define COPY(x) do { k->data.rsa.x##len = l->data.rsa.x##len ; k->data.rsa.x = (unsigned char *)s + m ; memcpy(s + m, t + l->data.rsa.x, l->data.rsa.x##len) ; m += l->data.rsa.x##len ; } while (0)
static inline size_t skey_copy (br_skey *k, sbearssl_skey const *l, char *s, char const *t)
{
size_t m = 0 ;
k->type = l->type ;
switch (l->type)
{
case BR_KEYTYPE_RSA :
k->data.rsa.n_bitlen = l->data.rsa.n_bitlen ;
COPY(p) ; COPY(q) ; COPY(dp) ; COPY(dq) ; COPY(iq) ;
break ;
case BR_KEYTYPE_EC :
k->data.ec.curve = l->data.ec.curve ;
k->data.ec.xlen = l->data.ec.xlen ; k->data.ec.x = (unsigned char *)s + m ; memcpy(s + m, t + l->data.ec.x, l->data.ec.xlen) ; m += l->data.ec.xlen ;
break ;
}
return m ;
}
static inline size_t cert_copy (br_x509_certificate *newc, sbearssl_cert const *oldc, char *s, char const *t)
{
memcpy(s, t + oldc->data, oldc->datalen) ;
newc->data = (unsigned char *)s ;
newc->data_len = oldc->datalen ;
return oldc->datalen ;
}
static int choose (br_ssl_server_policy_class const **pctx, br_ssl_server_context const *sc, br_ssl_server_choices *choices)
{
sbearssl_sni_policy_context *pol = INSTANCE(pctx) ;
sbearssl_sni_policy_node *node ;
char const *servername = br_ssl_engine_get_server_name(&sc->eng) ;
/* Get the node corresponding to the ServerName sent by the client. "" for no SNI. */
{
uint32_t n ;
if (!avltree_search(&pol->map, servername, &n))
{
if (!servername[0]) return 0 ;
if (!avltree_search(&pol->map, "", &n)) return 0 ;
}
avltree_free(&pol->map) ;
node = genalloc_s(sbearssl_sni_policy_node, &pol->mapga) + n ;
}
/* Replace certga and storage with the chosen chain and its data, free all the rest */
{
stralloc storage = STRALLOC_ZERO ;
genalloc certga = GENALLOC_ZERO ;
size_t clen = 0 ;
size_t m = 0 ;
sbearssl_cert const *certstart = genalloc_s(sbearssl_cert, &pol->certga) + node->chainindex ;
for (size_t i = 0 ; i < node->chainlen ; i++) clen += certstart[i].datalen ;
if (!stralloc_ready_tuned(&storage, sbearssl_skey_storagelen(&node->skey) + clen, 0, 0, 1)) return 0 ;
if (!genalloc_ready_tuned(br_x509_certificate, &certga, node->chainlen, 0, 0, 1))
{
stralloc_free(&storage) ;
return 0 ;
}
m += skey_copy(&pol->skey, &node->skey, storage.s + m, pol->storage.s) ;
for (size_t i = 0 ; i < node->chainlen ; i++)
m += cert_copy(genalloc_s(br_x509_certificate, &certga) + i, certstart + i, storage.s + m, pol->storage.s) ;
genalloc_setlen(br_x509_certificate, &certga, node->chainlen) ;
genalloc_free(sbearssl_sni_policy_node, &pol->mapga) ;
genalloc_free(sbearssl_cert, &pol->certga) ;
byte_zzero(pol->storage.s, pol->storage.len) ; /* contains skeys, so we wipe it */
stralloc_free(&pol->storage) ;
pol->certga = certga ;
pol->storage = storage ;
}
/* We got our choice of cert chain */
choices->chain = genalloc_s(br_x509_certificate, &pol->certga) ;
choices->chain_len = genalloc_len(br_x509_certificate, &pol->certga) ;
/* Now fill up the rest of the choices structure and gather info for later keyx/sign */
switch (pol->skey.type)
{
case BR_KEYTYPE_RSA :
if (!sbearssl_choose_algos_rsa(sc, choices, BR_KEYTYPE_KEYX | BR_KEYTYPE_SIGN)) return 0 ;
pol->keyx.rsa = br_rsa_private_get_default() ;
pol->sign.rsa = br_rsa_pkcs1_sign_get_default() ;
break ;
case BR_KEYTYPE_EC :
{
int kt ;
if (sbearssl_ec_issuer_keytype(&kt, &choices->chain[0])) return 0 ;
if (!sbearssl_choose_algos_ec(sc, choices, BR_KEYTYPE_KEYX | BR_KEYTYPE_SIGN, kt)) return 0 ;
pol->keyx.ec = sc->eng.iec ; /* the br_ssl_engine_get_ec() abstraction lacks a const */
pol->sign.ec = br_ecdsa_sign_asn1_get_default() ;
pol->mhash = &sc->eng.mhash ; /* missing an abstraction function there */
break ;
}
default : return 0 ;
}
return 1 ;
}
static uint32_t do_keyx (br_ssl_server_policy_class const **pctx, unsigned char *data, size_t *len)
{
sbearssl_sni_policy_context *pol = INSTANCE(pctx) ;
switch (pol->skey.type)
{
case BR_KEYTYPE_RSA :
return br_rsa_ssl_decrypt(pol->keyx.rsa, &pol->skey.data.rsa, data, *len) ;
case BR_KEYTYPE_EC :
{
size_t xlen ;
uint32_t r = pol->keyx.ec->mul(data, *len, pol->skey.data.ec.x, pol->skey.data.ec.xlen, pol->skey.data.ec.curve) ;
size_t xoff = pol->keyx.ec->xoff(pol->skey.data.ec.curve, &xlen) ;
memmove(data, data + xoff, xlen) ;
*len = xlen ;
return r ;
}
default : return 0 ;
}
}
static inline size_t sign_rsa (sbearssl_sni_policy_context *pol, unsigned int algo_id, unsigned char *data, size_t hv_len, size_t len)
{
static unsigned char const HASH_OID_SHA1[] = { 0x05, 0x2B, 0x0E, 0x03, 0x02, 0x1A } ;
static unsigned char const HASH_OID_SHA224[] = { 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04 } ;
static unsigned char const HASH_OID_SHA256[] = { 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01 } ;
static unsigned char const HASH_OID_SHA384[] = { 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02 } ;
static unsigned char const HASH_OID_SHA512[] = { 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03 } ;
static unsigned char const *HASH_OID[] = { HASH_OID_SHA1, HASH_OID_SHA224, HASH_OID_SHA256, HASH_OID_SHA384, HASH_OID_SHA512 } ;
unsigned char const *hash_oid = 0 ;
size_t sig_len ;
unsigned char hv[64] ;
memcpy(hv, data, hv_len) ;
algo_id &= 0xff ;
if (algo_id >= 2 && algo_id <= 6) hash_oid = HASH_OID[algo_id - 2] ;
else if (algo_id) return 0 ;
sig_len = (pol->skey.data.rsa.n_bitlen + 7) >> 3 ;
if (len < sig_len) return 0 ;
return pol->sign.rsa(hash_oid, hv, hv_len, &pol->skey.data.rsa, data) ? sig_len : 0 ;
}
static inline size_t sign_ec (sbearssl_sni_policy_context *pol, unsigned int algo_id, unsigned char *data, size_t hv_len, size_t len)
{
unsigned char hv[64] ;
br_hash_class const *hc = br_multihash_getimpl(pol->mhash, algo_id) ;
if (!hc) return 0 ;
memcpy(hv, data, hv_len) ;
if (len < 139) return 0 ;
return pol->sign.ec(pol->keyx.ec, hc, hv, &pol->skey.data.ec, data) ;
}
static size_t do_sign (br_ssl_server_policy_class const **pctx, unsigned int algo_id, unsigned char *data, size_t hv_len, size_t len)
{
sbearssl_sni_policy_context *pol = INSTANCE(pctx) ;
algo_id &= 0xff ; /* workaround for bearssl bug */
switch (pol->skey.type)
{
case BR_KEYTYPE_RSA : return sign_rsa(pol, algo_id, data, hv_len, len) ;
case BR_KEYTYPE_EC : return sign_ec(pol, algo_id, data, hv_len, len) ;
default : return 0 ;
}
}
br_ssl_server_policy_class const sbearssl_sni_policy_vtable =
{
.context_size = sizeof(sbearssl_sni_policy_context),
.choose = &choose,
.do_keyx = &do_keyx,
.do_sign = &do_sign
} ;
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