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authorJouni Malinen <jouni@codeaurora.org>2019-08-27 13:33:15 (GMT)
committerJouni Malinen <j@w1.fi>2019-10-15 12:39:19 (GMT)
commitefd42852993c791376aad3a67e1ef00f0cd642d2 (patch)
tree52fbb44d0cb675d711d96cfe7bbf2623a51c1e85
parentaeb022f8e51e82864934df0788a53de06f4567b0 (diff)
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SAE: Hash algorithm selection for H2E KCK/CN()
Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
-rw-r--r--src/common/sae.c140
-rw-r--r--src/common/sae.h7
2 files changed, 113 insertions, 34 deletions
diff --git a/src/common/sae.c b/src/common/sae.c
index 808dca0..39275bf 100644
--- a/src/common/sae.c
+++ b/src/common/sae.c
@@ -1484,32 +1484,99 @@ fail:
}
+static int sae_kdf_hash(size_t hash_len, const u8 *k, const char *label,
+ const u8 *context, size_t context_len,
+ u8 *out, size_t out_len)
+{
+ if (hash_len == 32)
+ return sha256_prf(k, hash_len, label,
+ context, context_len, out, out_len);
+#ifdef CONFIG_SHA384
+ if (hash_len == 48)
+ return sha384_prf(k, hash_len, label,
+ context, context_len, out, out_len);
+#endif /* CONFIG_SHA384 */
+#ifdef CONFIG_SHA512
+ if (hash_len == 64)
+ return sha512_prf(k, hash_len, label,
+ context, context_len, out, out_len);
+#endif /* CONFIG_SHA512 */
+ return -1;
+}
+
+
static int sae_derive_keys(struct sae_data *sae, const u8 *k)
{
- u8 null_key[SAE_KEYSEED_KEY_LEN], val[SAE_MAX_PRIME_LEN];
- u8 keyseed[SHA256_MAC_LEN];
- u8 keys[SAE_KCK_LEN + SAE_PMK_LEN];
+ u8 zero[SAE_MAX_HASH_LEN], val[SAE_MAX_PRIME_LEN];
+ const u8 *salt;
+ struct wpabuf *rejected_groups = NULL;
+ u8 keyseed[SAE_MAX_HASH_LEN];
+ u8 keys[SAE_MAX_HASH_LEN + SAE_PMK_LEN];
struct crypto_bignum *tmp;
int ret = -1;
+ size_t hash_len, salt_len, prime_len = sae->tmp->prime_len;
+ const u8 *addr[1];
+ size_t len[1];
tmp = crypto_bignum_init();
if (tmp == NULL)
goto fail;
- /* keyseed = H(<0>32, k)
- * KCK || PMK = KDF-512(keyseed, "SAE KCK and PMK",
+ /* keyseed = H(salt, k)
+ * KCK || PMK = KDF-Hash-Length(keyseed, "SAE KCK and PMK",
* (commit-scalar + peer-commit-scalar) modulo r)
* PMKID = L((commit-scalar + peer-commit-scalar) modulo r, 0, 128)
*/
+ if (!sae->tmp->h2e)
+ hash_len = SHA256_MAC_LEN;
+ else if (sae->tmp->dh)
+ hash_len = sae_ffc_prime_len_2_hash_len(prime_len);
+ else
+ hash_len = sae_ecc_prime_len_2_hash_len(prime_len);
+ if (sae->tmp->h2e && (sae->tmp->own_rejected_groups ||
+ sae->tmp->peer_rejected_groups)) {
+ struct wpabuf *own, *peer;
+
+ own = sae->tmp->own_rejected_groups;
+ peer = sae->tmp->peer_rejected_groups;
+ salt_len = 0;
+ if (own)
+ salt_len += wpabuf_len(own);
+ if (peer)
+ salt_len += wpabuf_len(peer);
+ rejected_groups = wpabuf_alloc(salt_len);
+ if (!rejected_groups)
+ goto fail;
+ if (sae->tmp->own_addr_higher) {
+ if (own)
+ wpabuf_put_buf(rejected_groups, own);
+ if (peer)
+ wpabuf_put_buf(rejected_groups, peer);
+ } else {
+ if (peer)
+ wpabuf_put_buf(rejected_groups, peer);
+ if (own)
+ wpabuf_put_buf(rejected_groups, own);
+ }
+ salt = wpabuf_head(rejected_groups);
+ salt_len = wpabuf_len(rejected_groups);
+ } else {
+ os_memset(zero, 0, hash_len);
+ salt = zero;
+ salt_len = hash_len;
+ }
+ wpa_hexdump(MSG_DEBUG, "SAE: salt for keyseed derivation",
+ salt, salt_len);
+ addr[0] = k;
+ len[0] = prime_len;
+ if (hkdf_extract(hash_len, salt, salt_len, 1, addr, len, keyseed) < 0)
+ goto fail;
+ wpa_hexdump_key(MSG_DEBUG, "SAE: keyseed", keyseed, hash_len);
- os_memset(null_key, 0, sizeof(null_key));
- hmac_sha256(null_key, sizeof(null_key), k, sae->tmp->prime_len,
- keyseed);
- wpa_hexdump_key(MSG_DEBUG, "SAE: keyseed", keyseed, sizeof(keyseed));
-
- crypto_bignum_add(sae->tmp->own_commit_scalar, sae->peer_commit_scalar,
- tmp);
- crypto_bignum_mod(tmp, sae->tmp->order, tmp);
+ if (crypto_bignum_add(sae->tmp->own_commit_scalar,
+ sae->peer_commit_scalar, tmp) < 0 ||
+ crypto_bignum_mod(tmp, sae->tmp->order, tmp) < 0)
+ goto fail;
/* IEEE Std 802.11-2016 is not exactly clear on the encoding of the bit
* string that is needed for KCK, PMK, and PMKID derivation, but it
* seems to make most sense to encode the
@@ -1518,19 +1585,23 @@ static int sae_derive_keys(struct sae_data *sae, const u8 *k)
* octets). */
crypto_bignum_to_bin(tmp, val, sizeof(val), sae->tmp->order_len);
wpa_hexdump(MSG_DEBUG, "SAE: PMKID", val, SAE_PMKID_LEN);
- if (sha256_prf(keyseed, sizeof(keyseed), "SAE KCK and PMK",
- val, sae->tmp->order_len, keys, sizeof(keys)) < 0)
+ if (sae_kdf_hash(hash_len, keyseed, "SAE KCK and PMK",
+ val, sae->tmp->order_len,
+ keys, hash_len + SAE_PMK_LEN) < 0)
goto fail;
- os_memset(keyseed, 0, sizeof(keyseed));
- os_memcpy(sae->tmp->kck, keys, SAE_KCK_LEN);
- os_memcpy(sae->pmk, keys + SAE_KCK_LEN, SAE_PMK_LEN);
+ forced_memzero(keyseed, sizeof(keyseed));
+ os_memcpy(sae->tmp->kck, keys, hash_len);
+ sae->tmp->kck_len = hash_len;
+ os_memcpy(sae->pmk, keys + hash_len, SAE_PMK_LEN);
os_memcpy(sae->pmkid, val, SAE_PMKID_LEN);
- os_memset(keys, 0, sizeof(keys));
- wpa_hexdump_key(MSG_DEBUG, "SAE: KCK", sae->tmp->kck, SAE_KCK_LEN);
+ forced_memzero(keys, sizeof(keys));
+ wpa_hexdump_key(MSG_DEBUG, "SAE: KCK",
+ sae->tmp->kck, sae->tmp->kck_len);
wpa_hexdump_key(MSG_DEBUG, "SAE: PMK", sae->pmk, SAE_PMK_LEN);
ret = 0;
fail:
+ wpabuf_free(rejected_groups);
crypto_bignum_deinit(tmp, 0);
return ret;
}
@@ -2044,8 +2115,8 @@ static int sae_cn_confirm(struct sae_data *sae, const u8 *sc,
len[3] = sae->tmp->prime_len;
addr[4] = element2;
len[4] = element2_len;
- return hmac_sha256_vector(sae->tmp->kck, sizeof(sae->tmp->kck),
- 5, addr, len, confirm);
+ return hkdf_extract(sae->tmp->kck_len, sae->tmp->kck, sae->tmp->kck_len,
+ 5, addr, len, confirm);
}
@@ -2097,10 +2168,13 @@ static int sae_cn_confirm_ffc(struct sae_data *sae, const u8 *sc,
void sae_write_confirm(struct sae_data *sae, struct wpabuf *buf)
{
const u8 *sc;
+ size_t hash_len;
if (sae->tmp == NULL)
return;
+ hash_len = sae->tmp->kck_len;
+
/* Send-Confirm */
sc = wpabuf_put(buf, 0);
wpabuf_put_le16(buf, sae->send_confirm);
@@ -2112,29 +2186,33 @@ void sae_write_confirm(struct sae_data *sae, struct wpabuf *buf)
sae->tmp->own_commit_element_ecc,
sae->peer_commit_scalar,
sae->tmp->peer_commit_element_ecc,
- wpabuf_put(buf, SHA256_MAC_LEN));
+ wpabuf_put(buf, hash_len));
else
sae_cn_confirm_ffc(sae, sc, sae->tmp->own_commit_scalar,
sae->tmp->own_commit_element_ffc,
sae->peer_commit_scalar,
sae->tmp->peer_commit_element_ffc,
- wpabuf_put(buf, SHA256_MAC_LEN));
+ wpabuf_put(buf, hash_len));
}
int sae_check_confirm(struct sae_data *sae, const u8 *data, size_t len)
{
- u8 verifier[SHA256_MAC_LEN];
+ u8 verifier[SAE_MAX_HASH_LEN];
+ size_t hash_len;
+
+ if (!sae->tmp)
+ return -1;
- if (len < 2 + SHA256_MAC_LEN) {
+ hash_len = sae->tmp->kck_len;
+ if (len < 2 + hash_len) {
wpa_printf(MSG_DEBUG, "SAE: Too short confirm message");
return -1;
}
wpa_printf(MSG_DEBUG, "SAE: peer-send-confirm %u", WPA_GET_LE16(data));
- if (!sae->tmp || !sae->peer_commit_scalar ||
- !sae->tmp->own_commit_scalar) {
+ if (!sae->peer_commit_scalar || !sae->tmp->own_commit_scalar) {
wpa_printf(MSG_DEBUG, "SAE: Temporary data not yet available");
return -1;
}
@@ -2159,12 +2237,12 @@ int sae_check_confirm(struct sae_data *sae, const u8 *data, size_t len)
return -1;
}
- if (os_memcmp_const(verifier, data + 2, SHA256_MAC_LEN) != 0) {
+ if (os_memcmp_const(verifier, data + 2, hash_len) != 0) {
wpa_printf(MSG_DEBUG, "SAE: Confirm mismatch");
wpa_hexdump(MSG_DEBUG, "SAE: Received confirm",
- data + 2, SHA256_MAC_LEN);
+ data + 2, hash_len);
wpa_hexdump(MSG_DEBUG, "SAE: Calculated verifier",
- verifier, SHA256_MAC_LEN);
+ verifier, hash_len);
return -1;
}
diff --git a/src/common/sae.h b/src/common/sae.h
index fdc2fd8..606e597 100644
--- a/src/common/sae.h
+++ b/src/common/sae.h
@@ -12,17 +12,18 @@
#define SAE_KCK_LEN 32
#define SAE_PMK_LEN 32
#define SAE_PMKID_LEN 16
-#define SAE_KEYSEED_KEY_LEN 32
#define SAE_MAX_PRIME_LEN 512
#define SAE_MAX_ECC_PRIME_LEN 66
+#define SAE_MAX_HASH_LEN 64
#define SAE_COMMIT_MAX_LEN (2 + 3 * SAE_MAX_PRIME_LEN)
-#define SAE_CONFIRM_MAX_LEN (2 + SAE_MAX_PRIME_LEN)
+#define SAE_CONFIRM_MAX_LEN (2 + SAE_MAX_HASH_LEN)
/* Special value returned by sae_parse_commit() */
#define SAE_SILENTLY_DISCARD 65535
struct sae_temporary_data {
- u8 kck[SAE_KCK_LEN];
+ u8 kck[SAE_MAX_HASH_LEN];
+ size_t kck_len;
struct crypto_bignum *own_commit_scalar;
struct crypto_bignum *own_commit_element_ffc;
struct crypto_ec_point *own_commit_element_ecc;