blob: 90fb89e243b83224b515368a3fad01532211e10d [file] [log] [blame]
/*
* IKEv2 common routines for initiator and responder
* Copyright (c) 2007, Jouni Malinen <j@w1.fi>
*
* This software may be distributed under the terms of the BSD license.
* See README for more details.
*/
#include "includes.h"
#include "common.h"
#include "crypto/crypto.h"
#include "crypto/md5.h"
#include "crypto/sha1.h"
#include "crypto/random.h"
#include "ikev2_common.h"
static const struct ikev2_integ_alg ikev2_integ_algs[] = {
{ AUTH_HMAC_SHA1_96, 20, 12 },
{ AUTH_HMAC_MD5_96, 16, 12 }
};
#define NUM_INTEG_ALGS ARRAY_SIZE(ikev2_integ_algs)
static const struct ikev2_prf_alg ikev2_prf_algs[] = {
{ PRF_HMAC_SHA1, 20, 20 },
{ PRF_HMAC_MD5, 16, 16 }
};
#define NUM_PRF_ALGS ARRAY_SIZE(ikev2_prf_algs)
static const struct ikev2_encr_alg ikev2_encr_algs[] = {
{ ENCR_AES_CBC, 16, 16 }, /* only 128-bit keys supported for now */
{ ENCR_3DES, 24, 8 }
};
#define NUM_ENCR_ALGS ARRAY_SIZE(ikev2_encr_algs)
const struct ikev2_integ_alg * ikev2_get_integ(int id)
{
size_t i;
for (i = 0; i < NUM_INTEG_ALGS; i++) {
if (ikev2_integ_algs[i].id == id)
return &ikev2_integ_algs[i];
}
return NULL;
}
int ikev2_integ_hash(int alg, const u8 *key, size_t key_len, const u8 *data,
size_t data_len, u8 *hash)
{
u8 tmphash[IKEV2_MAX_HASH_LEN];
switch (alg) {
case AUTH_HMAC_SHA1_96:
if (key_len != 20)
return -1;
if (hmac_sha1(key, key_len, data, data_len, tmphash) < 0)
return -1;
os_memcpy(hash, tmphash, 12);
break;
case AUTH_HMAC_MD5_96:
if (key_len != 16)
return -1;
if (hmac_md5(key, key_len, data, data_len, tmphash) < 0)
return -1;
os_memcpy(hash, tmphash, 12);
break;
default:
return -1;
}
return 0;
}
const struct ikev2_prf_alg * ikev2_get_prf(int id)
{
size_t i;
for (i = 0; i < NUM_PRF_ALGS; i++) {
if (ikev2_prf_algs[i].id == id)
return &ikev2_prf_algs[i];
}
return NULL;
}
int ikev2_prf_hash(int alg, const u8 *key, size_t key_len,
size_t num_elem, const u8 *addr[], const size_t *len,
u8 *hash)
{
switch (alg) {
case PRF_HMAC_SHA1:
return hmac_sha1_vector(key, key_len, num_elem, addr, len,
hash);
case PRF_HMAC_MD5:
return hmac_md5_vector(key, key_len, num_elem, addr, len, hash);
default:
return -1;
}
}
int ikev2_prf_plus(int alg, const u8 *key, size_t key_len,
const u8 *data, size_t data_len,
u8 *out, size_t out_len)
{
u8 hash[IKEV2_MAX_HASH_LEN];
size_t hash_len;
u8 iter, *pos, *end;
const u8 *addr[3];
size_t len[3];
const struct ikev2_prf_alg *prf;
int res;
prf = ikev2_get_prf(alg);
if (prf == NULL)
return -1;
hash_len = prf->hash_len;
addr[0] = hash;
len[0] = hash_len;
addr[1] = data;
len[1] = data_len;
addr[2] = &iter;
len[2] = 1;
pos = out;
end = out + out_len;
iter = 1;
while (pos < end) {
size_t clen;
if (iter == 1)
res = ikev2_prf_hash(alg, key, key_len, 2, &addr[1],
&len[1], hash);
else
res = ikev2_prf_hash(alg, key, key_len, 3, addr, len,
hash);
if (res < 0)
return -1;
clen = hash_len;
if ((int) clen > end - pos)
clen = end - pos;
os_memcpy(pos, hash, clen);
pos += clen;
iter++;
}
return 0;
}
const struct ikev2_encr_alg * ikev2_get_encr(int id)
{
size_t i;
for (i = 0; i < NUM_ENCR_ALGS; i++) {
if (ikev2_encr_algs[i].id == id)
return &ikev2_encr_algs[i];
}
return NULL;
}
int ikev2_encr_encrypt(int alg, const u8 *key, size_t key_len, const u8 *iv,
const u8 *plain, u8 *crypt, size_t len)
{
struct crypto_cipher *cipher;
int encr_alg;
switch (alg) {
case ENCR_3DES:
encr_alg = CRYPTO_CIPHER_ALG_3DES;
break;
case ENCR_AES_CBC:
encr_alg = CRYPTO_CIPHER_ALG_AES;
break;
default:
wpa_printf(MSG_DEBUG, "IKEV2: Unsupported encr alg %d", alg);
return -1;
}
cipher = crypto_cipher_init(encr_alg, iv, key, key_len);
if (cipher == NULL) {
wpa_printf(MSG_INFO, "IKEV2: Failed to initialize cipher");
return -1;
}
if (crypto_cipher_encrypt(cipher, plain, crypt, len) < 0) {
wpa_printf(MSG_INFO, "IKEV2: Encryption failed");
crypto_cipher_deinit(cipher);
return -1;
}
crypto_cipher_deinit(cipher);
return 0;
}
int ikev2_encr_decrypt(int alg, const u8 *key, size_t key_len, const u8 *iv,
const u8 *crypt, u8 *plain, size_t len)
{
struct crypto_cipher *cipher;
int encr_alg;
switch (alg) {
case ENCR_3DES:
encr_alg = CRYPTO_CIPHER_ALG_3DES;
break;
case ENCR_AES_CBC:
encr_alg = CRYPTO_CIPHER_ALG_AES;
break;
default:
wpa_printf(MSG_DEBUG, "IKEV2: Unsupported encr alg %d", alg);
return -1;
}
cipher = crypto_cipher_init(encr_alg, iv, key, key_len);
if (cipher == NULL) {
wpa_printf(MSG_INFO, "IKEV2: Failed to initialize cipher");
return -1;
}
if (crypto_cipher_decrypt(cipher, crypt, plain, len) < 0) {
wpa_printf(MSG_INFO, "IKEV2: Decryption failed");
crypto_cipher_deinit(cipher);
return -1;
}
crypto_cipher_deinit(cipher);
return 0;
}
int ikev2_parse_payloads(struct ikev2_payloads *payloads,
u8 next_payload, const u8 *pos, const u8 *end)
{
const struct ikev2_payload_hdr *phdr;
os_memset(payloads, 0, sizeof(*payloads));
while (next_payload != IKEV2_PAYLOAD_NO_NEXT_PAYLOAD) {
unsigned int plen, pdatalen, left;
const u8 *pdata;
wpa_printf(MSG_DEBUG, "IKEV2: Processing payload %u",
next_payload);
if (end < pos)
return -1;
left = end - pos;
if (left < sizeof(*phdr)) {
wpa_printf(MSG_INFO, "IKEV2: Too short message for "
"payload header (left=%ld)",
(long) (end - pos));
return -1;
}
phdr = (const struct ikev2_payload_hdr *) pos;
plen = WPA_GET_BE16(phdr->payload_length);
if (plen < sizeof(*phdr) || plen > left) {
wpa_printf(MSG_INFO, "IKEV2: Invalid payload header "
"length %d", plen);
return -1;
}
wpa_printf(MSG_DEBUG, "IKEV2: Next Payload: %u Flags: 0x%x"
" Payload Length: %u",
phdr->next_payload, phdr->flags, plen);
pdata = (const u8 *) (phdr + 1);
pdatalen = plen - sizeof(*phdr);
switch (next_payload) {
case IKEV2_PAYLOAD_SA:
wpa_printf(MSG_DEBUG, "IKEV2: Payload: Security "
"Association");
payloads->sa = pdata;
payloads->sa_len = pdatalen;
break;
case IKEV2_PAYLOAD_KEY_EXCHANGE:
wpa_printf(MSG_DEBUG, "IKEV2: Payload: Key "
"Exchange");
payloads->ke = pdata;
payloads->ke_len = pdatalen;
break;
case IKEV2_PAYLOAD_IDi:
wpa_printf(MSG_DEBUG, "IKEV2: Payload: IDi");
payloads->idi = pdata;
payloads->idi_len = pdatalen;
break;
case IKEV2_PAYLOAD_IDr:
wpa_printf(MSG_DEBUG, "IKEV2: Payload: IDr");
payloads->idr = pdata;
payloads->idr_len = pdatalen;
break;
case IKEV2_PAYLOAD_CERTIFICATE:
wpa_printf(MSG_DEBUG, "IKEV2: Payload: Certificate");
payloads->cert = pdata;
payloads->cert_len = pdatalen;
break;
case IKEV2_PAYLOAD_AUTHENTICATION:
wpa_printf(MSG_DEBUG, "IKEV2: Payload: "
"Authentication");
payloads->auth = pdata;
payloads->auth_len = pdatalen;
break;
case IKEV2_PAYLOAD_NONCE:
wpa_printf(MSG_DEBUG, "IKEV2: Payload: Nonce");
payloads->nonce = pdata;
payloads->nonce_len = pdatalen;
break;
case IKEV2_PAYLOAD_ENCRYPTED:
wpa_printf(MSG_DEBUG, "IKEV2: Payload: Encrypted");
payloads->encrypted = pdata;
payloads->encrypted_len = pdatalen;
break;
case IKEV2_PAYLOAD_NOTIFICATION:
wpa_printf(MSG_DEBUG, "IKEV2: Payload: "
"Notification");
payloads->notification = pdata;
payloads->notification_len = pdatalen;
break;
default:
if (phdr->flags & IKEV2_PAYLOAD_FLAGS_CRITICAL) {
wpa_printf(MSG_INFO, "IKEV2: Unsupported "
"critical payload %u - reject the "
"entire message", next_payload);
return -1;
} else {
wpa_printf(MSG_DEBUG, "IKEV2: Skipped "
"unsupported payload %u",
next_payload);
}
}
if (next_payload == IKEV2_PAYLOAD_ENCRYPTED &&
pos + plen == end) {
/*
* Next Payload in the case of Encrypted Payload is
* actually the payload type for the first embedded
* payload.
*/
payloads->encr_next_payload = phdr->next_payload;
next_payload = IKEV2_PAYLOAD_NO_NEXT_PAYLOAD;
} else
next_payload = phdr->next_payload;
pos += plen;
}
if (pos != end) {
wpa_printf(MSG_INFO, "IKEV2: Unexpected extra data after "
"payloads");
return -1;
}
return 0;
}
int ikev2_derive_auth_data(int prf_alg, const struct wpabuf *sign_msg,
const u8 *ID, size_t ID_len, u8 ID_type,
struct ikev2_keys *keys, int initiator,
const u8 *shared_secret, size_t shared_secret_len,
const u8 *nonce, size_t nonce_len,
const u8 *key_pad, size_t key_pad_len,
u8 *auth_data)
{
size_t sign_len, buf_len;
u8 *sign_data, *pos, *buf, hash[IKEV2_MAX_HASH_LEN];
const struct ikev2_prf_alg *prf;
const u8 *SK_p = initiator ? keys->SK_pi : keys->SK_pr;
prf = ikev2_get_prf(prf_alg);
if (sign_msg == NULL || ID == NULL || SK_p == NULL ||
shared_secret == NULL || nonce == NULL || prf == NULL)
return -1;
/* prf(SK_pi/r,IDi/r') */
buf_len = 4 + ID_len;
buf = os_zalloc(buf_len);
if (buf == NULL)
return -1;
buf[0] = ID_type;
os_memcpy(buf + 4, ID, ID_len);
if (ikev2_prf_hash(prf->id, SK_p, keys->SK_prf_len,
1, (const u8 **) &buf, &buf_len, hash) < 0) {
os_free(buf);
return -1;
}
os_free(buf);
/* sign_data = msg | Nr/i | prf(SK_pi/r,IDi/r') */
sign_len = wpabuf_len(sign_msg) + nonce_len + prf->hash_len;
sign_data = os_malloc(sign_len);
if (sign_data == NULL)
return -1;
pos = sign_data;
os_memcpy(pos, wpabuf_head(sign_msg), wpabuf_len(sign_msg));
pos += wpabuf_len(sign_msg);
os_memcpy(pos, nonce, nonce_len);
pos += nonce_len;
os_memcpy(pos, hash, prf->hash_len);
/* AUTH = prf(prf(Shared Secret, key pad, sign_data) */
if (ikev2_prf_hash(prf->id, shared_secret, shared_secret_len, 1,
&key_pad, &key_pad_len, hash) < 0 ||
ikev2_prf_hash(prf->id, hash, prf->hash_len, 1,
(const u8 **) &sign_data, &sign_len, auth_data) < 0)
{
os_free(sign_data);
return -1;
}
os_free(sign_data);
return 0;
}
u8 * ikev2_decrypt_payload(int encr_id, int integ_id,
struct ikev2_keys *keys, int initiator,
const struct ikev2_hdr *hdr,
const u8 *encrypted, size_t encrypted_len,
size_t *res_len)
{
size_t iv_len;
const u8 *pos, *end, *iv, *integ;
u8 hash[IKEV2_MAX_HASH_LEN], *decrypted;
size_t decrypted_len, pad_len;
const struct ikev2_integ_alg *integ_alg;
const struct ikev2_encr_alg *encr_alg;
const u8 *SK_e = initiator ? keys->SK_ei : keys->SK_er;
const u8 *SK_a = initiator ? keys->SK_ai : keys->SK_ar;
if (encrypted == NULL) {
wpa_printf(MSG_INFO, "IKEV2: No Encrypted payload in SA_AUTH");
return NULL;
}
encr_alg = ikev2_get_encr(encr_id);
if (encr_alg == NULL) {
wpa_printf(MSG_INFO, "IKEV2: Unsupported encryption type");
return NULL;
}
iv_len = encr_alg->block_size;
integ_alg = ikev2_get_integ(integ_id);
if (integ_alg == NULL) {
wpa_printf(MSG_INFO, "IKEV2: Unsupported intergrity type");
return NULL;
}
if (encrypted_len < iv_len + 1 + integ_alg->hash_len) {
wpa_printf(MSG_INFO, "IKEV2: No room for IV or Integrity "
"Checksum");
return NULL;
}
iv = encrypted;
pos = iv + iv_len;
end = encrypted + encrypted_len;
integ = end - integ_alg->hash_len;
if (SK_a == NULL) {
wpa_printf(MSG_INFO, "IKEV2: No SK_a available");
return NULL;
}
if (ikev2_integ_hash(integ_id, SK_a, keys->SK_integ_len,
(const u8 *) hdr,
integ - (const u8 *) hdr, hash) < 0) {
wpa_printf(MSG_INFO, "IKEV2: Failed to calculate integrity "
"hash");
return NULL;
}
if (os_memcmp_const(integ, hash, integ_alg->hash_len) != 0) {
wpa_printf(MSG_INFO, "IKEV2: Incorrect Integrity Checksum "
"Data");
return NULL;
}
if (SK_e == NULL) {
wpa_printf(MSG_INFO, "IKEV2: No SK_e available");
return NULL;
}
decrypted_len = integ - pos;
decrypted = os_malloc(decrypted_len);
if (decrypted == NULL)
return NULL;
if (ikev2_encr_decrypt(encr_alg->id, SK_e, keys->SK_encr_len, iv, pos,
decrypted, decrypted_len) < 0) {
os_free(decrypted);
return NULL;
}
pad_len = decrypted[decrypted_len - 1];
if (decrypted_len < pad_len + 1) {
wpa_printf(MSG_INFO, "IKEV2: Invalid padding in encrypted "
"payload");
os_free(decrypted);
return NULL;
}
decrypted_len -= pad_len + 1;
*res_len = decrypted_len;
return decrypted;
}
void ikev2_update_hdr(struct wpabuf *msg)
{
struct ikev2_hdr *hdr;
/* Update lenth field in HDR */
hdr = wpabuf_mhead(msg);
WPA_PUT_BE32(hdr->length, wpabuf_len(msg));
}
int ikev2_build_encrypted(int encr_id, int integ_id, struct ikev2_keys *keys,
int initiator, struct wpabuf *msg,
struct wpabuf *plain, u8 next_payload)
{
struct ikev2_payload_hdr *phdr;
size_t plen;
size_t iv_len, pad_len;
u8 *icv, *iv;
const struct ikev2_integ_alg *integ_alg;
const struct ikev2_encr_alg *encr_alg;
const u8 *SK_e = initiator ? keys->SK_ei : keys->SK_er;
const u8 *SK_a = initiator ? keys->SK_ai : keys->SK_ar;
wpa_printf(MSG_DEBUG, "IKEV2: Adding Encrypted payload");
/* Encr - RFC 4306, Sect. 3.14 */
encr_alg = ikev2_get_encr(encr_id);
if (encr_alg == NULL) {
wpa_printf(MSG_INFO, "IKEV2: Unsupported encryption type");
return -1;
}
iv_len = encr_alg->block_size;
integ_alg = ikev2_get_integ(integ_id);
if (integ_alg == NULL) {
wpa_printf(MSG_INFO, "IKEV2: Unsupported intergrity type");
return -1;
}
if (SK_e == NULL) {
wpa_printf(MSG_INFO, "IKEV2: No SK_e available");
return -1;
}
if (SK_a == NULL) {
wpa_printf(MSG_INFO, "IKEV2: No SK_a available");
return -1;
}
phdr = wpabuf_put(msg, sizeof(*phdr));
phdr->next_payload = next_payload;
phdr->flags = 0;
iv = wpabuf_put(msg, iv_len);
if (random_get_bytes(iv, iv_len)) {
wpa_printf(MSG_INFO, "IKEV2: Could not generate IV");
return -1;
}
pad_len = iv_len - (wpabuf_len(plain) + 1) % iv_len;
if (pad_len == iv_len)
pad_len = 0;
wpabuf_put(plain, pad_len);
wpabuf_put_u8(plain, pad_len);
if (ikev2_encr_encrypt(encr_alg->id, SK_e, keys->SK_encr_len, iv,
wpabuf_head(plain), wpabuf_mhead(plain),
wpabuf_len(plain)) < 0)
return -1;
wpabuf_put_buf(msg, plain);
/* Need to update all headers (Length fields) prior to hash func */
icv = wpabuf_put(msg, integ_alg->hash_len);
plen = (u8 *) wpabuf_put(msg, 0) - (u8 *) phdr;
WPA_PUT_BE16(phdr->payload_length, plen);
ikev2_update_hdr(msg);
return ikev2_integ_hash(integ_id, SK_a, keys->SK_integ_len,
wpabuf_head(msg),
wpabuf_len(msg) - integ_alg->hash_len, icv);
return 0;
}
int ikev2_keys_set(struct ikev2_keys *keys)
{
return keys->SK_d && keys->SK_ai && keys->SK_ar && keys->SK_ei &&
keys->SK_er && keys->SK_pi && keys->SK_pr;
}
void ikev2_free_keys(struct ikev2_keys *keys)
{
os_free(keys->SK_d);
os_free(keys->SK_ai);
os_free(keys->SK_ar);
os_free(keys->SK_ei);
os_free(keys->SK_er);
os_free(keys->SK_pi);
os_free(keys->SK_pr);
keys->SK_d = keys->SK_ai = keys->SK_ar = keys->SK_ei = keys->SK_er =
keys->SK_pi = keys->SK_pr = NULL;
}
int ikev2_derive_sk_keys(const struct ikev2_prf_alg *prf,
const struct ikev2_integ_alg *integ,
const struct ikev2_encr_alg *encr,
const u8 *skeyseed, const u8 *data, size_t data_len,
struct ikev2_keys *keys)
{
u8 *keybuf, *pos;
size_t keybuf_len;
/*
* {SK_d | SK_ai | SK_ar | SK_ei | SK_er | SK_pi | SK_pr } =
* prf+(SKEYSEED, Ni | Nr | SPIi | SPIr )
*/
ikev2_free_keys(keys);
keys->SK_d_len = prf->key_len;
keys->SK_integ_len = integ->key_len;
keys->SK_encr_len = encr->key_len;
keys->SK_prf_len = prf->key_len;
keybuf_len = keys->SK_d_len + 2 * keys->SK_integ_len +
2 * keys->SK_encr_len + 2 * keys->SK_prf_len;
keybuf = os_malloc(keybuf_len);
if (keybuf == NULL)
return -1;
if (ikev2_prf_plus(prf->id, skeyseed, prf->hash_len,
data, data_len, keybuf, keybuf_len)) {
os_free(keybuf);
return -1;
}
pos = keybuf;
keys->SK_d = os_malloc(keys->SK_d_len);
if (keys->SK_d) {
os_memcpy(keys->SK_d, pos, keys->SK_d_len);
wpa_hexdump_key(MSG_DEBUG, "IKEV2: SK_d",
keys->SK_d, keys->SK_d_len);
}
pos += keys->SK_d_len;
keys->SK_ai = os_malloc(keys->SK_integ_len);
if (keys->SK_ai) {
os_memcpy(keys->SK_ai, pos, keys->SK_integ_len);
wpa_hexdump_key(MSG_DEBUG, "IKEV2: SK_ai",
keys->SK_ai, keys->SK_integ_len);
}
pos += keys->SK_integ_len;
keys->SK_ar = os_malloc(keys->SK_integ_len);
if (keys->SK_ar) {
os_memcpy(keys->SK_ar, pos, keys->SK_integ_len);
wpa_hexdump_key(MSG_DEBUG, "IKEV2: SK_ar",
keys->SK_ar, keys->SK_integ_len);
}
pos += keys->SK_integ_len;
keys->SK_ei = os_malloc(keys->SK_encr_len);
if (keys->SK_ei) {
os_memcpy(keys->SK_ei, pos, keys->SK_encr_len);
wpa_hexdump_key(MSG_DEBUG, "IKEV2: SK_ei",
keys->SK_ei, keys->SK_encr_len);
}
pos += keys->SK_encr_len;
keys->SK_er = os_malloc(keys->SK_encr_len);
if (keys->SK_er) {
os_memcpy(keys->SK_er, pos, keys->SK_encr_len);
wpa_hexdump_key(MSG_DEBUG, "IKEV2: SK_er",
keys->SK_er, keys->SK_encr_len);
}
pos += keys->SK_encr_len;
keys->SK_pi = os_malloc(keys->SK_prf_len);
if (keys->SK_pi) {
os_memcpy(keys->SK_pi, pos, keys->SK_prf_len);
wpa_hexdump_key(MSG_DEBUG, "IKEV2: SK_pi",
keys->SK_pi, keys->SK_prf_len);
}
pos += keys->SK_prf_len;
keys->SK_pr = os_malloc(keys->SK_prf_len);
if (keys->SK_pr) {
os_memcpy(keys->SK_pr, pos, keys->SK_prf_len);
wpa_hexdump_key(MSG_DEBUG, "IKEV2: SK_pr",
keys->SK_pr, keys->SK_prf_len);
}
os_free(keybuf);
if (!ikev2_keys_set(keys)) {
ikev2_free_keys(keys);
return -1;
}
return 0;
}