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Downgrade 'invalid result from curve25519 handshake: 4' warning

Browse Source 
Also, refactor the way we handle failed handshakes so that this
warning doesn't propagate itself to "onion_skin_client_handshake
failed" and "circuit_finish_handshake failed" and
"connection_edge_process_relay_cell (at origin) failed."

Resolves warning from 9635.
This commit is contained in:
Nick Mathewson 2014-10-16 13:26:42 -04:00
parent ab4b29625d
commit fb91d647ac
15 changed files with 76 additions and 39 deletions
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3
changes/bug9635 Normal file
View File

@ -0,0 +1,3 @@
o Downgraded warnings:
- Don't warn when we've attempted to contact a relay using the wrong
ntor onion key. Closes ticket 9635.

12
src/or/circuitbuild.c
View File

@ -1256,8 +1256,10 @@ circuit_finish_handshake(origin_circuit_t *circ,
crypt_path_t *hop;
int rv;
if ((rv = pathbias_count_build_attempt(circ)) < 0)
if ((rv = pathbias_count_build_attempt(circ)) < 0) {
log_warn(LD_CIRC, "pathbias_count_build_attempt failed: %d", rv);
return rv;
}
if (circ->cpath->state == CPATH_STATE_AWAITING_KEYS) {
hop = circ->cpath;
@ -1271,12 +1273,15 @@ circuit_finish_handshake(origin_circuit_t *circ,
tor_assert(hop->state == CPATH_STATE_AWAITING_KEYS);
{
const char *msg = NULL;
if (onion_skin_client_handshake(hop->handshake_state.tag,
&hop->handshake_state,
reply->reply, reply->handshake_len,
(uint8_t*)keys, sizeof(keys),
(uint8_t*)hop->rend_circ_nonce) < 0) {
log_warn(LD_CIRC,"onion_skin_client_handshake failed.");
(uint8_t*)hop->rend_circ_nonce,
&msg) < 0) {
if (msg)
log_warn(LD_CIRC,"onion_skin_client_handshake failed: %s", msg);
return -END_CIRC_REASON_TORPROTOCOL;
}
}
@ -1284,6 +1289,7 @@ circuit_finish_handshake(origin_circuit_t *circ,
onion_handshake_state_release(&hop->handshake_state);
if (circuit_init_cpath_crypto(hop, keys, 0)<0) {
log_warn(LD_BUG, "Couldn't initialize cpath crypto");
return -END_CIRC_REASON_TORPROTOCOL;
}

1
src/or/command.c
View File

@ -398,7 +398,6 @@ command_process_created_cell(cell_t *cell, channel_t *chan)
log_debug(LD_OR,"at OP. Finishing handshake.");
if ((err_reason = circuit_finish_handshake(origin_circ,
&extended_cell.created_cell)) < 0) {
log_warn(LD_OR,"circuit_finish_handshake failed.");
circuit_mark_for_close(circ, -err_reason);
return;
}

24
src/or/onion.c
View File

@ -541,13 +541,15 @@ onion_skin_server_handshake(int type,
* bytes worth of key material in <b>keys_out_len</b>, set
* <b>rend_authenticator_out</b> to the "KH" field that can be used to
* establish introduction points at this hop, and return 0. On failure,
* return -1. */
* return -1, and set *msg_out to an error message if this is worth
* complaining to the usre about. */
int
onion_skin_client_handshake(int type,
const onion_handshake_state_t *handshake_state,
const uint8_t *reply, size_t reply_len,
uint8_t *keys_out, size_t keys_out_len,
uint8_t *rend_authenticator_out)
uint8_t *rend_authenticator_out,
const char **msg_out)
{
if (handshake_state->tag != type)
return -1;
@ -555,12 +557,14 @@ onion_skin_client_handshake(int type,
switch (type) {
case ONION_HANDSHAKE_TYPE_TAP:
if (reply_len != TAP_ONIONSKIN_REPLY_LEN) {
log_warn(LD_CIRC, "TAP reply was not of the correct length.");
if (msg_out)
*msg_out = "TAP reply was not of the correct length.";
return -1;
}
if (onion_skin_TAP_client_handshake(handshake_state->u.tap,
(const char*)reply,
(char *)keys_out, keys_out_len) < 0)
(char *)keys_out, keys_out_len,
msg_out) < 0)
return -1;
memcpy(rend_authenticator_out, reply+DH_KEY_LEN, DIGEST_LEN);
@ -568,11 +572,12 @@ onion_skin_client_handshake(int type,
return 0;
case ONION_HANDSHAKE_TYPE_FAST:
if (reply_len != CREATED_FAST_LEN) {
log_warn(LD_CIRC, "CREATED_FAST reply was not of the correct length.");
if (msg_out)
*msg_out = "TAP reply was not of the correct length.";
return -1;
}
if (fast_client_handshake(handshake_state->u.fast, reply,
keys_out, keys_out_len) < 0)
keys_out, keys_out_len, msg_out) < 0)
return -1;
memcpy(rend_authenticator_out, reply+DIGEST_LEN, DIGEST_LEN);
@ -580,15 +585,16 @@ onion_skin_client_handshake(int type,
#ifdef CURVE25519_ENABLED
case ONION_HANDSHAKE_TYPE_NTOR:
if (reply_len < NTOR_REPLY_LEN) {
log_warn(LD_CIRC, "ntor reply was not of the correct length.");
if (msg_out)
*msg_out = "ntor reply was not of the correct length.";
return -1;
}
{
size_t keys_tmp_len = keys_out_len + DIGEST_LEN;
uint8_t *keys_tmp = tor_malloc(keys_tmp_len);
if (onion_skin_ntor_client_handshake(handshake_state->u.ntor,
reply,
keys_tmp, keys_tmp_len) < 0) {
reply,
keys_tmp, keys_tmp_len, msg_out) < 0) {
tor_free(keys_tmp);
return -1;
}

3
src/or/onion.h
View File

@ -51,7 +51,8 @@ int onion_skin_client_handshake(int type,
const onion_handshake_state_t *handshake_state,
const uint8_t *reply, size_t reply_len,
uint8_t *keys_out, size_t key_out_len,
uint8_t *rend_authenticator_out);
uint8_t *rend_authenticator_out,
const char **msg_out);
/** A parsed CREATE, CREATE_FAST, or CREATE2 cell. */
typedef struct create_cell_t {

10
src/or/onion_fast.c
View File

@ -92,7 +92,8 @@ int
fast_client_handshake(const fast_handshake_state_t *handshake_state,
const uint8_t *handshake_reply_out,/*DIGEST_LEN*2 bytes*/
uint8_t *key_out,
size_t key_out_len)
size_t key_out_len,
const char **msg_out)
{
uint8_t tmp[DIGEST_LEN+DIGEST_LEN];
uint8_t *out;
@ -104,13 +105,14 @@ fast_client_handshake(const fast_handshake_state_t *handshake_state,
out_len = key_out_len+DIGEST_LEN;
out = tor_malloc(out_len);
if (crypto_expand_key_material_TAP(tmp, sizeof(tmp), out, out_len)) {
log_warn(LD_CIRC, "Failed to expand key material");
if (msg_out)
*msg_out = "Failed to expand key material";
goto done;
}
if (tor_memneq(out, handshake_reply_out+DIGEST_LEN, DIGEST_LEN)) {
/* H(K) does *not* match. Something fishy. */
log_warn(LD_PROTOCOL,"Digest DOES NOT MATCH on fast handshake. "
"Bug or attack.");
if (msg_out)
*msg_out = "Digest DOES NOT MATCH on fast handshake. Bug or attack.";
goto done;
}
memcpy(key_out, out+DIGEST_LEN, key_out_len);

3
src/or/onion_fast.h
View File

@ -32,7 +32,8 @@ int fast_server_handshake(const uint8_t *message_in,
int fast_client_handshake(const fast_handshake_state_t *handshake_state,
const uint8_t *handshake_reply_out,
uint8_t *key_out,
size_t key_out_len);
size_t key_out_len,
const char **msg_out);
#endif

19
src/or/onion_ntor.c
View File

@ -3,8 +3,8 @@
#include "orconfig.h"
#include "crypto.h"
#define ONION_NTOR_PRIVATE
#include "crypto.h"
#include "onion_ntor.h"
#include "torlog.h"
#include "util.h"
@ -226,7 +226,8 @@ onion_skin_ntor_client_handshake(
const ntor_handshake_state_t *handshake_state,
const uint8_t *handshake_reply,
uint8_t *key_out,
size_t key_out_len)
size_t key_out_len,
const char **msg_out)
{
const tweakset_t *T = &proto1_tweaks;
/* Sensitive stack-allocated material. Kept in an anonymous struct to make
@ -291,8 +292,18 @@ onion_skin_ntor_client_handshake(
memwipe(&s, 0, sizeof(s));
if (bad) {
log_warn(LD_PROTOCOL, "Invalid result from curve25519 handshake: %d", bad);
if (bad && msg_out) {
if (bad & 4) {
*msg_out = NULL; /* Don't report this one; we probably just had the
* wrong onion key.*/
log_fn(LOG_INFO, LD_PROTOCOL,
"Invalid result from curve25519 handshake: %d", bad);
}
if (bad & 3) {
*msg_out = "Zero output from curve25519 handshake";
log_fn(LOG_WARN, LD_PROTOCOL,
"Invalid result from curve25519 handshake: %d", bad);
}
}
return bad ? -1 : 0;

3
src/or/onion_ntor.h
View File

@ -37,7 +37,8 @@ int onion_skin_ntor_client_handshake(
const ntor_handshake_state_t *handshake_state,
const uint8_t *handshake_reply,
uint8_t *key_out,
size_t key_out_len);
size_t key_out_len,
const char **msg_out);
#ifdef ONION_NTOR_PRIVATE

10
src/or/onion_tap.c
View File

@ -183,7 +183,8 @@ int
onion_skin_TAP_client_handshake(crypto_dh_t *handshake_state,
const char *handshake_reply, /* TAP_ONIONSKIN_REPLY_LEN bytes */
char *key_out,
size_t key_out_len)
size_t key_out_len,
const char **msg_out)
{
ssize_t len;
char *key_material=NULL;
@ -196,14 +197,15 @@ onion_skin_TAP_client_handshake(crypto_dh_t *handshake_state,
handshake_reply, DH_KEY_LEN, key_material,
key_material_len);
if (len < 0) {
log_warn(LD_PROTOCOL,"DH computation failed.");
if (msg_out)
*msg_out = "DH computation failed.";
goto err;
}
if (tor_memneq(key_material, handshake_reply+DH_KEY_LEN, DIGEST_LEN)) {
/* H(K) does *not* match. Something fishy. */
log_warn(LD_PROTOCOL,"Digest DOES NOT MATCH on onion handshake. "
"Bug or attack.");
if (msg_out)
*msg_out = "Digest DOES NOT MATCH on onion handshake. Bug or attack.";
goto err;
}

3
src/or/onion_tap.h
View File

@ -31,7 +31,8 @@ int onion_skin_TAP_server_handshake(const char *onion_skin,
int onion_skin_TAP_client_handshake(crypto_dh_t *handshake_state,
const char *handshake_reply,
char *key_out,
size_t key_out_len);
size_t key_out_len,
const char **msg_out);
#endif

5
src/or/relay.c
View File

@ -1643,8 +1643,9 @@ connection_edge_process_relay_cell(cell_t *cell, circuit_t *circ,
}
if ((reason = circuit_finish_handshake(TO_ORIGIN_CIRCUIT(circ),
&extended_cell.created_cell)) < 0) {
log_warn(domain,"circuit_finish_handshake failed.");
return reason;
circuit_mark_for_close(circ, -reason);
return 0; /* We don't want to cause a warning, so we mark the circuit
* here. */
}
}
if ((reason=circuit_send_next_onion_skin(TO_ORIGIN_CIRCUIT(circ)))<0) {

6
src/test/bench.c
View File

@ -162,7 +162,8 @@ bench_onion_TAP(void)
char key_out[CPATH_KEY_MATERIAL_LEN];
int s;
dh = crypto_dh_dup(dh_out);
s = onion_skin_TAP_client_handshake(dh, or, key_out, sizeof(key_out));
s = onion_skin_TAP_client_handshake(dh, or, key_out, sizeof(key_out),
NULL);
crypto_dh_free(dh);
tor_assert(s == 0);
}
@ -222,7 +223,8 @@ bench_onion_ntor(void)
for (i = 0; i < iters; ++i) {
uint8_t key_out[CPATH_KEY_MATERIAL_LEN];
int s;
s = onion_skin_ntor_client_handshake(state, or, key_out, sizeof(key_out));
s = onion_skin_ntor_client_handshake(state, or, key_out, sizeof(key_out),
NULL);
tor_assert(s == 0);
}
end = perftime();

11
src/test/test.c
View File

@ -264,7 +264,8 @@ test_onion_handshake(void)
/* client handshake 2 */
memset(c_keys, 0, 40);
test_assert(! onion_skin_TAP_client_handshake(c_dh, s_buf, c_keys, 40));
test_assert(! onion_skin_TAP_client_handshake(c_dh, s_buf, c_keys, 40,
NULL));
test_memeq(c_keys, s_keys, 40);
memset(s_buf, 0, 40);
@ -337,18 +338,18 @@ test_bad_onion_handshake(void *arg)
/* Client: Case 1: The server sent back junk. */
s_buf[64] ^= 33;
tt_int_op(-1, ==,
onion_skin_TAP_client_handshake(c_dh, s_buf, c_keys, 40));
onion_skin_TAP_client_handshake(c_dh, s_buf, c_keys, 40, NULL));
s_buf[64] ^= 33;
/* Let the client finish; make sure it can. */
tt_int_op(0, ==,
onion_skin_TAP_client_handshake(c_dh, s_buf, c_keys, 40));
onion_skin_TAP_client_handshake(c_dh, s_buf, c_keys, 40, NULL));
test_memeq(s_keys, c_keys, 40);
/* Client: Case 2: The server sent back a degenerate DH. */
memset(s_buf, 0, sizeof(s_buf));
tt_int_op(-1, ==,
onion_skin_TAP_client_handshake(c_dh, s_buf, c_keys, 40));
onion_skin_TAP_client_handshake(c_dh, s_buf, c_keys, 40, NULL));
done:
crypto_dh_free(c_dh);
@ -398,7 +399,7 @@ test_ntor_handshake(void *arg)
/* client handshake 2 */
memset(c_keys, 0, 40);
tt_int_op(0, ==, onion_skin_ntor_client_handshake(c_state, s_buf,
c_keys, 400));
c_keys, 400, NULL));
test_memeq(c_keys, s_keys, 400);
memset(s_buf, 0, 40);

2
src/test/test_ntor_cl.c
View File

@ -130,7 +130,7 @@ client2(int argc, char **argv)
keys = tor_malloc(keybytes);
hexkeys = tor_malloc(keybytes*2+1);
if (onion_skin_ntor_client_handshake(&state, msg, keys, keybytes)<0) {
if (onion_skin_ntor_client_handshake(&state, msg, keys, keybytes, NULL)<0) {
fprintf(stderr, "handshake failed");
result = 2;
goto done;