Commit 32bbc8f6 authored by Nick Mathewson's avatar Nick Mathewson 🎨
Browse files

Refactor the dependency between tortls and crypto_dh.

We only ever need this to get us a DH ephemeral key object,
so make a function that does just that.
parent ac9a470c
......@@ -50,7 +50,6 @@ void crypto_dh_free_all(void);
/* Prototypes for private functions only used by tortls.c, crypto.c, and the
* unit tests. */
struct dh_st;
struct dh_st *crypto_dh_get_dh_(crypto_dh_t *dh);
struct dh_st *crypto_dh_new_openssl_tls(void);
#endif /* !defined(TOR_CRYPTO_DH_H) */
......@@ -27,6 +27,7 @@ ENABLE_GCC_WARNING(redundant-decls)
#include <string.h>
static int tor_check_dh_key(int severity, const BIGNUM *bn);
static DH *new_openssl_dh_from_params(BIGNUM *p, BIGNUM *g);
/** A structure to hold the first half (x, g^x) of a Diffie-Hellman handshake
* while we're waiting for the second.*/
......@@ -34,14 +35,6 @@ struct crypto_dh_t {
DH *dh; /**< The openssl DH object */
};
/** Used by tortls.c: Get the DH* from a crypto_dh_t.
*/
DH *
crypto_dh_get_dh_(crypto_dh_t *dh)
{
return dh->dh;
}
/** Shared P parameter for our circuit-crypto DH key exchanges. */
static BIGNUM *dh_param_p = NULL;
/** Shared P parameter for our TLS DH key exchanges. */
......@@ -188,6 +181,14 @@ init_dh_param(void)
*/
#define DH_PRIVATE_KEY_BITS 320
/** Used by tortls.c: Get the DH* for use with TLS.
*/
DH *
crypto_dh_new_openssl_tls(void)
{
return new_openssl_dh_from_params(dh_param_p_tls, dh_param_g);
}
/** Allocate and return a new DH object for a key exchange. Returns NULL on
* failure.
*/
......@@ -202,55 +203,59 @@ crypto_dh_new(int dh_type)
if (!dh_param_p)
init_dh_param();
if (!(res->dh = DH_new()))
goto err;
#ifdef OPENSSL_1_1_API
BIGNUM *dh_p = NULL, *dh_g = NULL;
BIGNUM *dh_p = NULL;
if (dh_type == DH_TYPE_TLS) {
dh_p = BN_dup(dh_param_p_tls);
dh_p = dh_param_p_tls;
} else {
dh_p = BN_dup(dh_param_p);
dh_p = dh_param_p;
}
res->dh = new_openssl_dh_from_params(dh_p, dh_param_g);
if (res->dh == NULL)
tor_free(res); // sets res to NULL.
return res;
}
/** Create and return a new openssl DH from a given prime and generator. */
static DH *
new_openssl_dh_from_params(BIGNUM *p, BIGNUM *g)
{
DH *res_dh;
if (!(res_dh = DH_new()))
goto err;
BIGNUM *dh_p = NULL, *dh_g = NULL;
dh_p = BN_dup(p);
if (!dh_p)
goto err;
dh_g = BN_dup(dh_param_g);
dh_g = BN_dup(g);
if (!dh_g) {
BN_free(dh_p);
goto err;
}
if (!DH_set0_pqg(res->dh, dh_p, NULL, dh_g)) {
goto err;
}
#ifdef OPENSSL_1_1_API
if (!DH_set_length(res->dh, DH_PRIVATE_KEY_BITS))
if (!DH_set0_pqg(res_dh, dh_p, NULL, dh_g)) {
goto err;
#else /* !(defined(OPENSSL_1_1_API)) */
if (dh_type == DH_TYPE_TLS) {
if (!(res->dh->p = BN_dup(dh_param_p_tls)))
goto err;
} else {
if (!(res->dh->p = BN_dup(dh_param_p)))
goto err;
}
if (!(res->dh->g = BN_dup(dh_param_g)))
if (!DH_set_length(res_dh, DH_PRIVATE_KEY_BITS))
goto err;
res->dh->length = DH_PRIVATE_KEY_BITS;
#else /* !(defined(OPENSSL_1_1_API)) */
res_dh->p = dh_p;
res_dh->g = dh_g;
res_dh->length = DH_PRIVATE_KEY_BITS;
#endif /* defined(OPENSSL_1_1_API) */
return res;
return res_dh;
/* LCOV_EXCL_START
* This error condition is only reached when an allocation fails */
err:
crypto_openssl_log_errors(LOG_WARN, "creating DH object");
if (res->dh) DH_free(res->dh); /* frees p and g too */
tor_free(res);
if (res_dh) DH_free(res_dh); /* frees p and g too */
return NULL;
/* LCOV_EXCL_STOP */
}
......
......@@ -1280,10 +1280,10 @@ tor_tls_context_new(crypto_pk_t *identity, unsigned int key_lifetime,
goto error;
}
{
crypto_dh_t *dh = crypto_dh_new(DH_TYPE_TLS);
DH *dh = crypto_dh_new_openssl_tls();
tor_assert(dh);
SSL_CTX_set_tmp_dh(result->ctx, crypto_dh_get_dh_(dh));
crypto_dh_free(dh);
SSL_CTX_set_tmp_dh(result->ctx, dh);
DH_free(dh);
}
if (! is_client) {
int nid;
......
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