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Explicit length checks in create_rend_cpath(). 

Had to also edit hs_ntor_circuit_key_expansion() to make it happen.
This commit is contained in:
George Kadianakis 2017-07-06 16:23:30 +03:00 committed by Nick Mathewson
parent c4d17faf81
commit 70d08f764d
6 changed files with 34 additions and 11 deletions
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13
src/or/hs_circuit.c
View File

@ -48,13 +48,17 @@ circuit_purpose_is_correct_for_rend(unsigned int circ_purpose, int is_service_si
* If <b>is_service_side</b> is set, we are the hidden service and the final
* hop of the rendezvous circuit is the client on the other side. */
static crypt_path_t *
create_rend_cpath(const uint8_t *ntor_key_seed, int is_service_side)
create_rend_cpath(const uint8_t *ntor_key_seed, size_t seed_len,
int is_service_side)
{
uint8_t keys[HS_NTOR_KEY_EXPANSION_KDF_OUT_LEN];
crypt_path_t *cpath = NULL;
/* Do the key expansion */
hs_ntor_circuit_key_expansion(ntor_key_seed, keys);
if (hs_ntor_circuit_key_expansion(ntor_key_seed, seed_len,
keys, sizeof(keys)) < 0) {
goto err;
}
/* Setup the cpath */
cpath = tor_malloc_zero(sizeof(crypt_path_t));
@ -171,7 +175,7 @@ finalize_rend_circuit(origin_circuit_t *circ, crypt_path_t *hop,
* Return 0 if the operation went well; in case of error return -1. */
int
hs_circuit_setup_e2e_rend_circ(origin_circuit_t *circ,
const uint8_t *ntor_key_seed,
const uint8_t *ntor_key_seed, size_t seed_len,
int is_service_side)
{
if (BUG(!circuit_purpose_is_correct_for_rend(TO_CIRCUIT(circ)->purpose,
@ -179,7 +183,8 @@ hs_circuit_setup_e2e_rend_circ(origin_circuit_t *circ,
return -1;
}
crypt_path_t *hop = create_rend_cpath(ntor_key_seed, is_service_side);
crypt_path_t *hop = create_rend_cpath(ntor_key_seed, seed_len,
is_service_side);
if (!hop) {
log_warn(LD_REND, "Couldn't get v3 %s cpath!",
is_service_side ? "service-side" : "client-side");

1
src/or/hs_circuit.h
View File

@ -15,6 +15,7 @@
int hs_circuit_setup_e2e_rend_circ(origin_circuit_t *circ,
const uint8_t *ntor_key_seed,
size_t seed_len,
int is_service_side);
int hs_circuit_setup_e2e_rend_circ_legacy_client(origin_circuit_t *circ,
const uint8_t *rend_cell_body);

19
src/or/hs_ntor.c
View File

@ -582,14 +582,25 @@ hs_ntor_client_rendezvous2_mac_is_good(
/** Given the rendezvous key seed in <b>ntor_key_seed</b> (of size
* DIGEST256_LEN), do the circuit key expansion as specified by section
* '4.2.1. Key expansion' and place the keys in <b>keys_out</b> (which must be
* of size HS_NTOR_KEY_EXPANSION_KDF_OUT_LEN). */
void
hs_ntor_circuit_key_expansion(const uint8_t *ntor_key_seed, uint8_t *keys_out)
* of size HS_NTOR_KEY_EXPANSION_KDF_OUT_LEN).
*
* Return 0 if things went well, else return -1. */
int
hs_ntor_circuit_key_expansion(const uint8_t *ntor_key_seed, size_t seed_len,
uint8_t *keys_out, size_t keys_out_len)
{
uint8_t *ptr;
uint8_t kdf_input[NTOR_KEY_EXPANSION_KDF_INPUT_LEN];
crypto_xof_t *xof;
/* Sanity checks on lengths to make sure we are good */
if (BUG(seed_len != DIGEST256_LEN)) {
return -1;
}
if (BUG(keys_out_len != HS_NTOR_KEY_EXPANSION_KDF_OUT_LEN)) {
return -1;
}
/* Let's build the input to the KDF */
ptr = kdf_input;
APPEND(ptr, ntor_key_seed, DIGEST256_LEN);
@ -601,5 +612,7 @@ hs_ntor_circuit_key_expansion(const uint8_t *ntor_key_seed, uint8_t *keys_out)
crypto_xof_add_bytes(xof, kdf_input, sizeof(kdf_input));
crypto_xof_squeeze_bytes(xof, keys_out, HS_NTOR_KEY_EXPANSION_KDF_OUT_LEN);
crypto_xof_free(xof);
return 0;
}

4
src/or/hs_ntor.h
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@ -55,8 +55,8 @@ int hs_ntor_service_get_rendezvous1_keys(
const curve25519_public_key_t *client_ephemeral_enc_pubkey,
hs_ntor_rend_cell_keys_t *hs_ntor_rend_cell_keys_out);
void hs_ntor_circuit_key_expansion(const uint8_t *ntor_key_seed,
uint8_t *keys_out);
int hs_ntor_circuit_key_expansion(const uint8_t *ntor_key_seed, size_t seed_len,
uint8_t *keys_out, size_t keys_out_len);
int hs_ntor_client_rendezvous2_mac_is_good(
const hs_ntor_rend_cell_keys_t *hs_ntor_rend_cell_keys,

4
src/test/test_hs_client.c
View File

@ -243,7 +243,9 @@ test_e2e_rend_circuit_setup(void *arg)
/**********************************************/
/* Setup the circuit */
retval = hs_circuit_setup_e2e_rend_circ(or_circ, ntor_key_seed, 0);
retval = hs_circuit_setup_e2e_rend_circ(or_circ,
ntor_key_seed, sizeof(ntor_key_seed),
0);
tt_int_op(retval, OP_EQ, 0);
/**********************************************/

4
src/test/test_hs_service.c
View File

@ -290,7 +290,9 @@ test_e2e_rend_circuit_setup(void *arg)
/* Setup the circuit: do the ntor key exchange */
{
uint8_t ntor_key_seed[DIGEST256_LEN] = {2};
retval = hs_circuit_setup_e2e_rend_circ(or_circ, ntor_key_seed, 1);
retval = hs_circuit_setup_e2e_rend_circ(or_circ,
ntor_key_seed, sizeof(ntor_key_seed),
1);
tt_int_op(retval, OP_EQ, 0);
}