--- libtorrent-0.12.2.orig/src/utils/diffie_hellman.cc Wed May 7 12:19:12 2008
+++ libtorrent-0.12.2/src/utils/diffie_hellman.cc Sun Jun 15 10:51:31 2008
@@ -47,6 +47,80 @@
namespace torrent {
+static int generate_key(DH *dh)
+ {
+ int ok=0;
+ int generate_new_key=0;
+ unsigned l;
+ BN_CTX *ctx;
+ BN_MONT_CTX *mont=NULL;
+ BIGNUM *pub_key=NULL,*priv_key=NULL;
+
+ ctx = BN_CTX_new();
+ if (ctx == NULL) goto err;
+
+ if (dh->priv_key == NULL)
+ {
+ priv_key=BN_new();
+ if (priv_key == NULL) goto err;
+ generate_new_key=1;
+ }
+ else
+ priv_key=dh->priv_key;
+
+ if (dh->pub_key == NULL)
+ {
+ pub_key=BN_new();
+ if (pub_key == NULL) goto err;
+ }
+ else
+ pub_key=dh->pub_key;
+
+
+ if (dh->flags & DH_FLAG_CACHE_MONT_P)
+ {
+ mont = BN_MONT_CTX_set_locked((BN_MONT_CTX **)(&dh->method_mont_p),
+ CRYPTO_LOCK_DH, dh->p, ctx);
+ if (!mont)
+ goto err;
+ }
+
+ if (generate_new_key)
+ {
+ l = dh->length ? dh->length : BN_num_bits(dh->p)-1; /* secret exponent length */
+ if (!BN_rand(priv_key, l, 0, 0))
+ if (!BN_pseudo_rand(priv_key, l, 0, 0)) goto err;
+ }
+
+ {
+ BIGNUM local_prk;
+ BIGNUM *prk;
+
+ if ((dh->flags & DH_FLAG_NO_EXP_CONSTTIME) == 0)
+ {
+ BN_init(&local_prk);
+ prk = &local_prk;
+ BN_with_flags(prk, priv_key, BN_FLG_EXP_CONSTTIME);
+ }
+ else
+ prk = priv_key;
+
+ if (!dh->meth->bn_mod_exp(dh, pub_key, dh->g, prk, dh->p, ctx, mont)) goto err;
+ }
+
+ dh->pub_key=pub_key;
+ dh->priv_key=priv_key;
+ ok=1;
+err:
+ if (ok != 1) {
+ }
+
+ if ((pub_key != NULL) && (dh->pub_key == NULL)) BN_free(pub_key);
+ if ((priv_key != NULL) && (dh->priv_key == NULL)) BN_free(priv_key);
+ BN_CTX_free(ctx);
+ return(ok);
+}
+
DiffieHellman::DiffieHellman(const unsigned char *prime, int primeLength,
const unsigned char *generator, int generatorLength) :
m_secret(NULL) {
@@ -56,7 +130,8 @@
m_dh->p = BN_bin2bn(prime, primeLength, NULL);
m_dh->g = BN_bin2bn(generator, generatorLength, NULL);
- DH_generate_key(m_dh);
+ if (!generate_key(m_dh))
+ throw internal_error("Unable to generate encryption key.");
#else
throw internal_error("Compiled without encryption support.");
#endif