Commit 91825372 authored by Nick Mathewson's avatar Nick Mathewson 👁
Browse files

Fix the periodic bug that would make handshaking fail.

The culprit: sometimes DH_calculate_key returns less than DH_KEY_LEN bytes;
we needed to check the return value.


svn:r322
parent 9af577fe
......@@ -777,7 +777,7 @@ int crypto_dh_compute_secret(crypto_dh_env_t *dh,
if (secret_len == -1)
return -1;
return 0;
return secret_len;
}
void crypto_dh_free(crypto_dh_env_t *dh)
{
......
......@@ -474,6 +474,7 @@ onion_skin_server_handshake(char *onion_skin, /* DH_ONIONSKIN_LEN bytes long */
crypto_dh_env_t *dh = NULL;
crypto_cipher_env_t *cipher = NULL;
int pkbytes;
int len;
memset(iv, 0, 16);
pkbytes = crypto_pk_keysize(private_key);
......@@ -515,10 +516,11 @@ onion_skin_server_handshake(char *onion_skin, /* DH_ONIONSKIN_LEN bytes long */
puts("");
#endif
if (crypto_dh_compute_secret(dh, buf+16, DH_KEY_LEN, buf))
len = crypto_dh_compute_secret(dh, buf+16, DH_KEY_LEN, buf);
if (len < 0)
goto err;
memcpy(key_out, buf+DH_KEY_LEN-key_out_len, key_out_len);
memcpy(key_out, buf+len-key_out_len, key_out_len);
#ifdef DEBUG_ONION_SKINS
printf("Server: keys out:");
......@@ -550,6 +552,7 @@ onion_skin_client_handshake(crypto_dh_env_t *handshake_state,
int key_out_len)
{
char key_material[DH_KEY_LEN];
int len;
assert(crypto_dh_get_bytes(handshake_state) == DH_KEY_LEN);
memset(key_material, 0, DH_KEY_LEN);
......@@ -562,11 +565,12 @@ onion_skin_client_handshake(crypto_dh_env_t *handshake_state,
puts("");
#endif
if (crypto_dh_compute_secret(handshake_state, handshake_reply, DH_KEY_LEN,
key_material))
len = crypto_dh_compute_secret(handshake_state, handshake_reply, DH_KEY_LEN,
key_material);
if (len < 0)
return -1;
memcpy(key_out, key_material+DH_KEY_LEN-key_out_len, key_out_len);
memcpy(key_out, key_material+len-key_out_len, key_out_len);
#ifdef DEBUG_ONION_SKINS
printf("Client: keys out:");
......
......@@ -165,6 +165,7 @@ test_crypto_dh()
char p2[CRYPTO_DH_SIZE];
char s1[CRYPTO_DH_SIZE];
char s2[CRYPTO_DH_SIZE];
int s1len, s2len;
dh1 = crypto_dh_new();
dh2 = crypto_dh_new();
......@@ -180,10 +181,12 @@ test_crypto_dh()
test_memneq(p1, p2, CRYPTO_DH_SIZE);
memset(s1, 0, CRYPTO_DH_SIZE);
memset(s2, 0, CRYPTO_DH_SIZE);
test_assert(! crypto_dh_compute_secret(dh1, p2, CRYPTO_DH_SIZE, s1));
test_assert(! crypto_dh_compute_secret(dh2, p1, CRYPTO_DH_SIZE, s2));
test_memeq(s1, s2, CRYPTO_DH_SIZE);
memset(s2, 0xFF, CRYPTO_DH_SIZE);
s1len = crypto_dh_compute_secret(dh1, p2, CRYPTO_DH_SIZE, s1);
s2len = crypto_dh_compute_secret(dh2, p1, CRYPTO_DH_SIZE, s2);
test_assert(s1len > 0);
test_eq(s1len, s2len);
test_memeq(s1, s2, s1len);
crypto_dh_free(dh1);
crypto_dh_free(dh2);
......@@ -597,22 +600,18 @@ main(int c, char**v) {
#ifndef DEBUG_ONION_SKINS
puts("========================== Buffers =========================");
test_buffers();
puts("========================== Crypto ==========================");
puts("\n========================== Crypto ==========================");
test_crypto();
test_crypto_dh();
puts("\n========================= Util ============================");
test_util();
puts("\n========================= Onion Skins =====================");
#endif
#ifdef DEBUG_ONION_SKINS
crypto_seed_rng();
while(1) {
#endif
test_onion_handshake();
#ifdef DEBUG_ONION_SKINS
fflush(NULL);
}
#endif
puts("\n========================= Directory Formats ===============");
test_dir_format();
puts("");
......
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