From 0741c481ee1c1ff2997dd519e368316642426b1c Mon Sep 17 00:00:00 2001 From: Jouni Malinen Date: Sun, 27 Mar 2016 21:43:24 +0300 Subject: [PATCH] SAE: Check SHA256-PRF operation result While this is mostly theoretical, check explicitly that SHA256 operations in sha256_prf*() succeed. Signed-off-by: Jouni Malinen --- src/common/sae.c | 19 +++++++++++-------- src/crypto/sha256-prf.c | 26 +++++++++++++++++--------- src/crypto/sha256.h | 12 ++++++------ 3 files changed, 34 insertions(+), 23 deletions(-) diff --git a/src/common/sae.c b/src/common/sae.c index f78437b13..9f70f036b 100644 --- a/src/common/sae.c +++ b/src/common/sae.c @@ -1,6 +1,6 @@ /* * Simultaneous authentication of equals - * Copyright (c) 2012-2015, Jouni Malinen + * Copyright (c) 2012-2016, Jouni Malinen * * This software may be distributed under the terms of the BSD license. * See README for more details. @@ -275,8 +275,9 @@ static int sae_test_pwd_seed_ecc(struct sae_data *sae, const u8 *pwd_seed, /* pwd-value = KDF-z(pwd-seed, "SAE Hunting and Pecking", p) */ bits = crypto_ec_prime_len_bits(sae->tmp->ec); - sha256_prf_bits(pwd_seed, SHA256_MAC_LEN, "SAE Hunting and Pecking", - prime, sae->tmp->prime_len, pwd_value, bits); + if (sha256_prf_bits(pwd_seed, SHA256_MAC_LEN, "SAE Hunting and Pecking", + prime, sae->tmp->prime_len, pwd_value, bits) < 0) + return -1; if (bits % 8) buf_shift_right(pwd_value, sizeof(pwd_value), 8 - bits % 8); wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-value", @@ -318,9 +319,10 @@ static int sae_test_pwd_seed_ffc(struct sae_data *sae, const u8 *pwd_seed, wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-seed", pwd_seed, SHA256_MAC_LEN); /* pwd-value = KDF-z(pwd-seed, "SAE Hunting and Pecking", p) */ - sha256_prf_bits(pwd_seed, SHA256_MAC_LEN, "SAE Hunting and Pecking", - sae->tmp->dh->prime, sae->tmp->prime_len, pwd_value, - bits); + if (sha256_prf_bits(pwd_seed, SHA256_MAC_LEN, "SAE Hunting and Pecking", + sae->tmp->dh->prime, sae->tmp->prime_len, pwd_value, + bits) < 0) + return -1; wpa_hexdump_key(MSG_DEBUG, "SAE: pwd-value", pwd_value, sae->tmp->prime_len); @@ -809,8 +811,9 @@ static int sae_derive_keys(struct sae_data *sae, const u8 *k) crypto_bignum_mod(tmp, sae->tmp->order, tmp); crypto_bignum_to_bin(tmp, val, sizeof(val), sae->tmp->prime_len); wpa_hexdump(MSG_DEBUG, "SAE: PMKID", val, SAE_PMKID_LEN); - sha256_prf(keyseed, sizeof(keyseed), "SAE KCK and PMK", - val, sae->tmp->prime_len, keys, sizeof(keys)); + if (sha256_prf(keyseed, sizeof(keyseed), "SAE KCK and PMK", + val, sae->tmp->prime_len, keys, sizeof(keys)) < 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); diff --git a/src/crypto/sha256-prf.c b/src/crypto/sha256-prf.c index 79791c06c..722cad6bd 100644 --- a/src/crypto/sha256-prf.c +++ b/src/crypto/sha256-prf.c @@ -1,6 +1,6 @@ /* * SHA256-based PRF (IEEE 802.11r) - * Copyright (c) 2003-2013, Jouni Malinen + * Copyright (c) 2003-2016, Jouni Malinen * * This software may be distributed under the terms of the BSD license. * See README for more details. @@ -22,14 +22,16 @@ * @data_len: Length of the data * @buf: Buffer for the generated pseudo-random key * @buf_len: Number of bytes of key to generate + * Returns: 0 on success, -1 on failure * * This function is used to derive new, cryptographically separate keys from a * given key. */ -void sha256_prf(const u8 *key, size_t key_len, const char *label, +int sha256_prf(const u8 *key, size_t key_len, const char *label, const u8 *data, size_t data_len, u8 *buf, size_t buf_len) { - sha256_prf_bits(key, key_len, label, data, data_len, buf, buf_len * 8); + return sha256_prf_bits(key, key_len, label, data, data_len, buf, + buf_len * 8); } @@ -42,15 +44,16 @@ void sha256_prf(const u8 *key, size_t key_len, const char *label, * @data_len: Length of the data * @buf: Buffer for the generated pseudo-random key * @buf_len: Number of bits of key to generate + * Returns: 0 on success, -1 on failure * * This function is used to derive new, cryptographically separate keys from a * given key. If the requested buf_len is not divisible by eight, the least * significant 1-7 bits of the last octet in the output are not part of the * requested output. */ -void sha256_prf_bits(const u8 *key, size_t key_len, const char *label, - const u8 *data, size_t data_len, u8 *buf, - size_t buf_len_bits) +int sha256_prf_bits(const u8 *key, size_t key_len, const char *label, + const u8 *data, size_t data_len, u8 *buf, + size_t buf_len_bits) { u16 counter = 1; size_t pos, plen; @@ -75,11 +78,14 @@ void sha256_prf_bits(const u8 *key, size_t key_len, const char *label, plen = buf_len - pos; WPA_PUT_LE16(counter_le, counter); if (plen >= SHA256_MAC_LEN) { - hmac_sha256_vector(key, key_len, 4, addr, len, - &buf[pos]); + if (hmac_sha256_vector(key, key_len, 4, addr, len, + &buf[pos]) < 0) + return -1; pos += SHA256_MAC_LEN; } else { - hmac_sha256_vector(key, key_len, 4, addr, len, hash); + if (hmac_sha256_vector(key, key_len, 4, addr, len, + hash) < 0) + return -1; os_memcpy(&buf[pos], hash, plen); pos += plen; break; @@ -97,4 +103,6 @@ void sha256_prf_bits(const u8 *key, size_t key_len, const char *label, } os_memset(hash, 0, sizeof(hash)); + + return 0; } diff --git a/src/crypto/sha256.h b/src/crypto/sha256.h index b15f51158..5219022ed 100644 --- a/src/crypto/sha256.h +++ b/src/crypto/sha256.h @@ -1,6 +1,6 @@ /* * SHA256 hash implementation and interface functions - * Copyright (c) 2003-2014, Jouni Malinen + * Copyright (c) 2003-2016, Jouni Malinen * * This software may be distributed under the terms of the BSD license. * See README for more details. @@ -15,11 +15,11 @@ int hmac_sha256_vector(const u8 *key, size_t key_len, size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac); int hmac_sha256(const u8 *key, size_t key_len, const u8 *data, size_t data_len, u8 *mac); -void sha256_prf(const u8 *key, size_t key_len, const char *label, - const u8 *data, size_t data_len, u8 *buf, size_t buf_len); -void sha256_prf_bits(const u8 *key, size_t key_len, const char *label, - const u8 *data, size_t data_len, u8 *buf, - size_t buf_len_bits); +int sha256_prf(const u8 *key, size_t key_len, const char *label, + const u8 *data, size_t data_len, u8 *buf, size_t buf_len); +int sha256_prf_bits(const u8 *key, size_t key_len, const char *label, + const u8 *data, size_t data_len, u8 *buf, + size_t buf_len_bits); void tls_prf_sha256(const u8 *secret, size_t secret_len, const char *label, const u8 *seed, size_t seed_len, u8 *out, size_t outlen);