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hostap/src/eap_server/ikev2.c
Jouni Malinen 675ddad1c2 EAP-IKEv2: Use os_memcmp_const() for hash/password comparisons 
This makes the implementation less likely to provide useful timing
information to potential attackers from comparisons of information
received from a remote device and private material known only by the
authorized devices.

Signed-off-by: Jouni Malinen <j@w1.fi>
2014-07-02 12:38:47 +03:00

1200 lines
30 KiB
C
Raw Blame History

/*
* IKEv2 initiator (RFC 4306) for EAP-IKEV2
* 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/dh_groups.h"
#include "crypto/random.h"
#include "ikev2.h"
static int ikev2_process_idr(struct ikev2_initiator_data *data,
const u8 *idr, size_t idr_len);
void ikev2_initiator_deinit(struct ikev2_initiator_data *data)
{
ikev2_free_keys(&data->keys);
wpabuf_free(data->r_dh_public);
wpabuf_free(data->i_dh_private);
os_free(data->IDi);
os_free(data->IDr);
os_free(data->shared_secret);
wpabuf_free(data->i_sign_msg);
wpabuf_free(data->r_sign_msg);
os_free(data->key_pad);
}
static int ikev2_derive_keys(struct ikev2_initiator_data *data)
{
u8 *buf, *pos, *pad, skeyseed[IKEV2_MAX_HASH_LEN];
size_t buf_len, pad_len;
struct wpabuf *shared;
const struct ikev2_integ_alg *integ;
const struct ikev2_prf_alg *prf;
const struct ikev2_encr_alg *encr;
int ret;
const u8 *addr[2];
size_t len[2];
/* RFC 4306, Sect. 2.14 */
integ = ikev2_get_integ(data->proposal.integ);
prf = ikev2_get_prf(data->proposal.prf);
encr = ikev2_get_encr(data->proposal.encr);
if (integ == NULL || prf == NULL || encr == NULL) {
wpa_printf(MSG_INFO, "IKEV2: Unsupported proposal");
return -1;
}
shared = dh_derive_shared(data->r_dh_public, data->i_dh_private,
data->dh);
if (shared == NULL)
return -1;
/* Construct Ni | Nr | SPIi | SPIr */
buf_len = data->i_nonce_len + data->r_nonce_len + 2 * IKEV2_SPI_LEN;
buf = os_malloc(buf_len);
if (buf == NULL) {
wpabuf_free(shared);
return -1;
}
pos = buf;
os_memcpy(pos, data->i_nonce, data->i_nonce_len);
pos += data->i_nonce_len;
os_memcpy(pos, data->r_nonce, data->r_nonce_len);
pos += data->r_nonce_len;
os_memcpy(pos, data->i_spi, IKEV2_SPI_LEN);
pos += IKEV2_SPI_LEN;
os_memcpy(pos, data->r_spi, IKEV2_SPI_LEN);
/* SKEYSEED = prf(Ni | Nr, g^ir) */
/* Use zero-padding per RFC 4306, Sect. 2.14 */
pad_len = data->dh->prime_len - wpabuf_len(shared);
pad = os_zalloc(pad_len ? pad_len : 1);
if (pad == NULL) {
wpabuf_free(shared);
os_free(buf);
return -1;
}
addr[0] = pad;
len[0] = pad_len;
addr[1] = wpabuf_head(shared);
len[1] = wpabuf_len(shared);
if (ikev2_prf_hash(prf->id, buf, data->i_nonce_len + data->r_nonce_len,
2, addr, len, skeyseed) < 0) {
wpabuf_free(shared);
os_free(buf);
os_free(pad);
return -1;
}
os_free(pad);
wpabuf_free(shared);
/* DH parameters are not needed anymore, so free them */
wpabuf_free(data->r_dh_public);
data->r_dh_public = NULL;
wpabuf_free(data->i_dh_private);
data->i_dh_private = NULL;
wpa_hexdump_key(MSG_DEBUG, "IKEV2: SKEYSEED",
skeyseed, prf->hash_len);
ret = ikev2_derive_sk_keys(prf, integ, encr, skeyseed, buf, buf_len,
&data->keys);
os_free(buf);
return ret;
}
static int ikev2_parse_transform(struct ikev2_initiator_data *data,
struct ikev2_proposal_data *prop,
const u8 *pos, const u8 *end)
{
int transform_len;
const struct ikev2_transform *t;
u16 transform_id;
const u8 *tend;
if (end - pos < (int) sizeof(*t)) {
wpa_printf(MSG_INFO, "IKEV2: Too short transform");
return -1;
}
t = (const struct ikev2_transform *) pos;
transform_len = WPA_GET_BE16(t->transform_length);
if (transform_len < (int) sizeof(*t) || pos + transform_len > end) {
wpa_printf(MSG_INFO, "IKEV2: Invalid transform length %d",
transform_len);
return -1;
}
tend = pos + transform_len;
transform_id = WPA_GET_BE16(t->transform_id);
wpa_printf(MSG_DEBUG, "IKEV2: Transform:");
wpa_printf(MSG_DEBUG, "IKEV2: Type: %d Transform Length: %d "
"Transform Type: %d Transform ID: %d",
t->type, transform_len, t->transform_type, transform_id);
if (t->type != 0 && t->type != 3) {
wpa_printf(MSG_INFO, "IKEV2: Unexpected Transform type");
return -1;
}
pos = (const u8 *) (t + 1);
if (pos < tend) {
wpa_hexdump(MSG_DEBUG, "IKEV2: Transform Attributes",
pos, tend - pos);
}
switch (t->transform_type) {
case IKEV2_TRANSFORM_ENCR:
if (ikev2_get_encr(transform_id) &&
transform_id == data->proposal.encr) {
if (transform_id == ENCR_AES_CBC) {
if (tend - pos != 4) {
wpa_printf(MSG_DEBUG, "IKEV2: No "
"Transform Attr for AES");
break;
}
if (WPA_GET_BE16(pos) != 0x800e) {
wpa_printf(MSG_DEBUG, "IKEV2: Not a "
"Key Size attribute for "
"AES");
break;
}
if (WPA_GET_BE16(pos + 2) != 128) {
wpa_printf(MSG_DEBUG, "IKEV2: "
"Unsupported AES key size "
"%d bits",
WPA_GET_BE16(pos + 2));
break;
}
}
prop->encr = transform_id;
}
break;
case IKEV2_TRANSFORM_PRF:
if (ikev2_get_prf(transform_id) &&
transform_id == data->proposal.prf)
prop->prf = transform_id;
break;
case IKEV2_TRANSFORM_INTEG:
if (ikev2_get_integ(transform_id) &&
transform_id == data->proposal.integ)
prop->integ = transform_id;
break;
case IKEV2_TRANSFORM_DH:
if (dh_groups_get(transform_id) &&
transform_id == data->proposal.dh)
prop->dh = transform_id;
break;
}
return transform_len;
}
static int ikev2_parse_proposal(struct ikev2_initiator_data *data,
struct ikev2_proposal_data *prop,
const u8 *pos, const u8 *end)
{
const u8 *pend, *ppos;
int proposal_len, i;
const struct ikev2_proposal *p;
if (end - pos < (int) sizeof(*p)) {
wpa_printf(MSG_INFO, "IKEV2: Too short proposal");
return -1;
}
p = (const struct ikev2_proposal *) pos;
proposal_len = WPA_GET_BE16(p->proposal_length);
if (proposal_len < (int) sizeof(*p) || pos + proposal_len > end) {
wpa_printf(MSG_INFO, "IKEV2: Invalid proposal length %d",
proposal_len);
return -1;
}
wpa_printf(MSG_DEBUG, "IKEV2: SAi1 Proposal # %d",
p->proposal_num);
wpa_printf(MSG_DEBUG, "IKEV2: Type: %d Proposal Length: %d "
" Protocol ID: %d",
p->type, proposal_len, p->protocol_id);
wpa_printf(MSG_DEBUG, "IKEV2: SPI Size: %d Transforms: %d",
p->spi_size, p->num_transforms);
if (p->type != 0 && p->type != 2) {
wpa_printf(MSG_INFO, "IKEV2: Unexpected Proposal type");
return -1;
}
if (p->protocol_id != IKEV2_PROTOCOL_IKE) {
wpa_printf(MSG_DEBUG, "IKEV2: Unexpected Protocol ID "
"(only IKE allowed for EAP-IKEv2)");
return -1;
}
if (p->proposal_num != prop->proposal_num) {
if (p->proposal_num == prop->proposal_num + 1)
prop->proposal_num = p->proposal_num;
else {
wpa_printf(MSG_INFO, "IKEV2: Unexpected Proposal #");
return -1;
}
}
ppos = (const u8 *) (p + 1);
pend = pos + proposal_len;
if (ppos + p->spi_size > pend) {
wpa_printf(MSG_INFO, "IKEV2: Not enough room for SPI "
"in proposal");
return -1;
}
if (p->spi_size) {
wpa_hexdump(MSG_DEBUG, "IKEV2: SPI",
ppos, p->spi_size);
ppos += p->spi_size;
}
/*
* For initial IKE_SA negotiation, SPI Size MUST be zero; for
* subsequent negotiations, it must be 8 for IKE. We only support
* initial case for now.
*/
if (p->spi_size != 0) {
wpa_printf(MSG_INFO, "IKEV2: Unexpected SPI Size");
return -1;
}
if (p->num_transforms == 0) {
wpa_printf(MSG_INFO, "IKEV2: At least one transform required");
return -1;
}
for (i = 0; i < (int) p->num_transforms; i++) {
int tlen = ikev2_parse_transform(data, prop, ppos, pend);
if (tlen < 0)
return -1;
ppos += tlen;
}
if (ppos != pend) {
wpa_printf(MSG_INFO, "IKEV2: Unexpected data after "
"transforms");
return -1;
}
return proposal_len;
}
static int ikev2_process_sar1(struct ikev2_initiator_data *data,
const u8 *sar1, size_t sar1_len)
{
struct ikev2_proposal_data prop;
const u8 *pos, *end;
int found = 0;
/* Security Association Payloads: <Proposals> */
if (sar1 == NULL) {
wpa_printf(MSG_INFO, "IKEV2: SAr1 not received");
return -1;
}
os_memset(&prop, 0, sizeof(prop));
prop.proposal_num = 1;
pos = sar1;
end = sar1 + sar1_len;
while (pos < end) {
int plen;
prop.integ = -1;
prop.prf = -1;
prop.encr = -1;
prop.dh = -1;
plen = ikev2_parse_proposal(data, &prop, pos, end);
if (plen < 0)
return -1;
if (!found && prop.integ != -1 && prop.prf != -1 &&
prop.encr != -1 && prop.dh != -1) {
found = 1;
}
pos += plen;
/* Only one proposal expected in SAr */
break;
}
if (pos != end) {
wpa_printf(MSG_INFO, "IKEV2: Unexpected data after proposal");
return -1;
}
if (!found) {
wpa_printf(MSG_INFO, "IKEV2: No acceptable proposal found");
return -1;
}
wpa_printf(MSG_DEBUG, "IKEV2: Accepted proposal #%d: ENCR:%d PRF:%d "
"INTEG:%d D-H:%d", data->proposal.proposal_num,
data->proposal.encr, data->proposal.prf,
data->proposal.integ, data->proposal.dh);
return 0;
}
static int ikev2_process_ker(struct ikev2_initiator_data *data,
const u8 *ker, size_t ker_len)
{
u16 group;
/*
* Key Exchange Payload:
* DH Group # (16 bits)
* RESERVED (16 bits)
* Key Exchange Data (Diffie-Hellman public value)
*/
if (ker == NULL) {
wpa_printf(MSG_INFO, "IKEV2: KEr not received");
return -1;
}
if (ker_len < 4 + 96) {
wpa_printf(MSG_INFO, "IKEV2: Too show Key Exchange Payload");
return -1;
}
group = WPA_GET_BE16(ker);
wpa_printf(MSG_DEBUG, "IKEV2: KEr DH Group #%u", group);
if (group != data->proposal.dh) {
wpa_printf(MSG_DEBUG, "IKEV2: KEr DH Group #%u does not match "
"with the selected proposal (%u)",
group, data->proposal.dh);
return -1;
}
if (data->dh == NULL) {
wpa_printf(MSG_INFO, "IKEV2: Unsupported DH group");
return -1;
}
/* RFC 4306, Section 3.4:
* The length of DH public value MUST be equal to the length of the
* prime modulus.
*/
if (ker_len - 4 != data->dh->prime_len) {
wpa_printf(MSG_INFO, "IKEV2: Invalid DH public value length "
"%ld (expected %ld)",
(long) (ker_len - 4), (long) data->dh->prime_len);
return -1;
}
wpabuf_free(data->r_dh_public);
data->r_dh_public = wpabuf_alloc_copy(ker + 4, ker_len - 4);
if (data->r_dh_public == NULL)
return -1;
wpa_hexdump_buf(MSG_DEBUG, "IKEV2: KEr Diffie-Hellman Public Value",
data->r_dh_public);
return 0;
}
static int ikev2_process_nr(struct ikev2_initiator_data *data,
const u8 *nr, size_t nr_len)
{
if (nr == NULL) {
wpa_printf(MSG_INFO, "IKEV2: Nr not received");
return -1;
}
if (nr_len < IKEV2_NONCE_MIN_LEN || nr_len > IKEV2_NONCE_MAX_LEN) {
wpa_printf(MSG_INFO, "IKEV2: Invalid Nr length %ld",
(long) nr_len);
return -1;
}
data->r_nonce_len = nr_len;
os_memcpy(data->r_nonce, nr, nr_len);
wpa_hexdump(MSG_MSGDUMP, "IKEV2: Nr",
data->r_nonce, data->r_nonce_len);
return 0;
}
static int ikev2_process_sa_init_encr(struct ikev2_initiator_data *data,
const struct ikev2_hdr *hdr,
const u8 *encrypted,
size_t encrypted_len, u8 next_payload)
{
u8 *decrypted;
size_t decrypted_len;
struct ikev2_payloads pl;
int ret = 0;
decrypted = ikev2_decrypt_payload(data->proposal.encr,
data->proposal.integ, &data->keys, 0,
hdr, encrypted, encrypted_len,
&decrypted_len);
if (decrypted == NULL)
return -1;
wpa_printf(MSG_DEBUG, "IKEV2: Processing decrypted payloads");
if (ikev2_parse_payloads(&pl, next_payload, decrypted,
decrypted + decrypted_len) < 0) {
wpa_printf(MSG_INFO, "IKEV2: Failed to parse decrypted "
"payloads");
return -1;
}
if (pl.idr)
ret = ikev2_process_idr(data, pl.idr, pl.idr_len);
os_free(decrypted);
return ret;
}
static int ikev2_process_sa_init(struct ikev2_initiator_data *data,
const struct ikev2_hdr *hdr,
struct ikev2_payloads *pl)
{
if (ikev2_process_sar1(data, pl->sa, pl->sa_len) < 0 ||
ikev2_process_ker(data, pl->ke, pl->ke_len) < 0 ||
ikev2_process_nr(data, pl->nonce, pl->nonce_len) < 0)
return -1;
os_memcpy(data->r_spi, hdr->r_spi, IKEV2_SPI_LEN);
if (ikev2_derive_keys(data) < 0)
return -1;
if (pl->encrypted) {
wpa_printf(MSG_DEBUG, "IKEV2: Encrypted payload in SA_INIT - "
"try to get IDr from it");
if (ikev2_process_sa_init_encr(data, hdr, pl->encrypted,
pl->encrypted_len,
pl->encr_next_payload) < 0) {
wpa_printf(MSG_INFO, "IKEV2: Failed to process "
"encrypted payload");
return -1;
}
}
data->state = SA_AUTH;
return 0;
}
static int ikev2_process_idr(struct ikev2_initiator_data *data,
const u8 *idr, size_t idr_len)
{
u8 id_type;
if (idr == NULL) {
wpa_printf(MSG_INFO, "IKEV2: No IDr received");
return -1;
}
if (idr_len < 4) {
wpa_printf(MSG_INFO, "IKEV2: Too short IDr payload");
return -1;
}
id_type = idr[0];
idr += 4;
idr_len -= 4;
wpa_printf(MSG_DEBUG, "IKEV2: IDr ID Type %d", id_type);
wpa_hexdump_ascii(MSG_DEBUG, "IKEV2: IDr", idr, idr_len);
if (data->IDr) {
if (id_type != data->IDr_type || idr_len != data->IDr_len ||
os_memcmp(idr, data->IDr, idr_len) != 0) {
wpa_printf(MSG_INFO, "IKEV2: IDr differs from the one "
"received earlier");
wpa_printf(MSG_DEBUG, "IKEV2: Previous IDr ID Type %d",
id_type);
wpa_hexdump_ascii(MSG_DEBUG, "Previous IKEV2: IDr",
data->IDr, data->IDr_len);
return -1;
}
os_free(data->IDr);
}
data->IDr = os_malloc(idr_len);
if (data->IDr == NULL)
return -1;
os_memcpy(data->IDr, idr, idr_len);
data->IDr_len = idr_len;
data->IDr_type = id_type;
return 0;
}
static int ikev2_process_cert(struct ikev2_initiator_data *data,
const u8 *cert, size_t cert_len)
{
u8 cert_encoding;
if (cert == NULL) {
if (data->peer_auth == PEER_AUTH_CERT) {
wpa_printf(MSG_INFO, "IKEV2: No Certificate received");
return -1;
}
return 0;
}
if (cert_len < 1) {
wpa_printf(MSG_INFO, "IKEV2: No Cert Encoding field");
return -1;
}
cert_encoding = cert[0];
cert++;
cert_len--;
wpa_printf(MSG_DEBUG, "IKEV2: Cert Encoding %d", cert_encoding);
wpa_hexdump(MSG_MSGDUMP, "IKEV2: Certificate Data", cert, cert_len);
/* TODO: validate certificate */
return 0;
}
static int ikev2_process_auth_cert(struct ikev2_initiator_data *data,
u8 method, const u8 *auth, size_t auth_len)
{
if (method != AUTH_RSA_SIGN) {
wpa_printf(MSG_INFO, "IKEV2: Unsupported authentication "
"method %d", method);
return -1;
}
/* TODO: validate AUTH */
return 0;
}
static int ikev2_process_auth_secret(struct ikev2_initiator_data *data,
u8 method, const u8 *auth,
size_t auth_len)
{
u8 auth_data[IKEV2_MAX_HASH_LEN];
const struct ikev2_prf_alg *prf;
if (method != AUTH_SHARED_KEY_MIC) {
wpa_printf(MSG_INFO, "IKEV2: Unsupported authentication "
"method %d", method);
return -1;
}
/* msg | Ni | prf(SK_pr,IDr') */
if (ikev2_derive_auth_data(data->proposal.prf, data->r_sign_msg,
data->IDr, data->IDr_len, data->IDr_type,
&data->keys, 0, data->shared_secret,
data->shared_secret_len,
data->i_nonce, data->i_nonce_len,
data->key_pad, data->key_pad_len,
auth_data) < 0) {
wpa_printf(MSG_INFO, "IKEV2: Could not derive AUTH data");
return -1;
}
wpabuf_free(data->r_sign_msg);
data->r_sign_msg = NULL;
prf = ikev2_get_prf(data->proposal.prf);
if (prf == NULL)
return -1;
if (auth_len != prf->hash_len ||
os_memcmp_const(auth, auth_data, auth_len) != 0) {
wpa_printf(MSG_INFO, "IKEV2: Invalid Authentication Data");
wpa_hexdump(MSG_DEBUG, "IKEV2: Received Authentication Data",
auth, auth_len);
wpa_hexdump(MSG_DEBUG, "IKEV2: Expected Authentication Data",
auth_data, prf->hash_len);
return -1;
}
wpa_printf(MSG_DEBUG, "IKEV2: Peer authenticated successfully "
"using shared keys");
return 0;
}
static int ikev2_process_auth(struct ikev2_initiator_data *data,
const u8 *auth, size_t auth_len)
{
u8 auth_method;
if (auth == NULL) {
wpa_printf(MSG_INFO, "IKEV2: No Authentication Payload");
return -1;
}
if (auth_len < 4) {
wpa_printf(MSG_INFO, "IKEV2: Too short Authentication "
"Payload");
return -1;
}
auth_method = auth[0];
auth += 4;
auth_len -= 4;
wpa_printf(MSG_DEBUG, "IKEV2: Auth Method %d", auth_method);
wpa_hexdump(MSG_MSGDUMP, "IKEV2: Authentication Data", auth, auth_len);
switch (data->peer_auth) {
case PEER_AUTH_CERT:
return ikev2_process_auth_cert(data, auth_method, auth,
auth_len);
case PEER_AUTH_SECRET:
return ikev2_process_auth_secret(data, auth_method, auth,
auth_len);
}
return -1;
}
static int ikev2_process_sa_auth_decrypted(struct ikev2_initiator_data *data,
u8 next_payload,
u8 *payload, size_t payload_len)
{
struct ikev2_payloads pl;
wpa_printf(MSG_DEBUG, "IKEV2: Processing decrypted payloads");
if (ikev2_parse_payloads(&pl, next_payload, payload, payload +
payload_len) < 0) {
wpa_printf(MSG_INFO, "IKEV2: Failed to parse decrypted "
"payloads");
return -1;
}
if (ikev2_process_idr(data, pl.idr, pl.idr_len) < 0 ||
ikev2_process_cert(data, pl.cert, pl.cert_len) < 0 ||
ikev2_process_auth(data, pl.auth, pl.auth_len) < 0)
return -1;
return 0;
}
static int ikev2_process_sa_auth(struct ikev2_initiator_data *data,
const struct ikev2_hdr *hdr,
struct ikev2_payloads *pl)
{
u8 *decrypted;
size_t decrypted_len;
int ret;
decrypted = ikev2_decrypt_payload(data->proposal.encr,
data->proposal.integ,
&data->keys, 0, hdr, pl->encrypted,
pl->encrypted_len, &decrypted_len);
if (decrypted == NULL)
return -1;
ret = ikev2_process_sa_auth_decrypted(data, pl->encr_next_payload,
decrypted, decrypted_len);
os_free(decrypted);
if (ret == 0 && !data->unknown_user) {
wpa_printf(MSG_DEBUG, "IKEV2: Authentication completed");
data->state = IKEV2_DONE;
}
return ret;
}
static int ikev2_validate_rx_state(struct ikev2_initiator_data *data,
u8 exchange_type, u32 message_id)
{
switch (data->state) {
case SA_INIT:
/* Expect to receive IKE_SA_INIT: HDR, SAr, KEr, Nr, [CERTREQ],
* [SK{IDr}] */
if (exchange_type != IKE_SA_INIT) {
wpa_printf(MSG_INFO, "IKEV2: Unexpected Exchange Type "
"%u in SA_INIT state", exchange_type);
return -1;
}
if (message_id != 0) {
wpa_printf(MSG_INFO, "IKEV2: Unexpected Message ID %u "
"in SA_INIT state", message_id);
return -1;
}
break;
case SA_AUTH:
/* Expect to receive IKE_SA_AUTH:
* HDR, SK {IDr, [CERT,] [CERTREQ,] [NFID,] AUTH}
*/
if (exchange_type != IKE_SA_AUTH) {
wpa_printf(MSG_INFO, "IKEV2: Unexpected Exchange Type "
"%u in SA_AUTH state", exchange_type);
return -1;
}
if (message_id != 1) {
wpa_printf(MSG_INFO, "IKEV2: Unexpected Message ID %u "
"in SA_AUTH state", message_id);
return -1;
}
break;
case CHILD_SA:
if (exchange_type != CREATE_CHILD_SA) {
wpa_printf(MSG_INFO, "IKEV2: Unexpected Exchange Type "
"%u in CHILD_SA state", exchange_type);
return -1;
}
if (message_id != 2) {
wpa_printf(MSG_INFO, "IKEV2: Unexpected Message ID %u "
"in CHILD_SA state", message_id);
return -1;
}
break;
case IKEV2_DONE:
return -1;
}
return 0;
}
int ikev2_initiator_process(struct ikev2_initiator_data *data,
const struct wpabuf *buf)
{
const struct ikev2_hdr *hdr;
u32 length, message_id;
const u8 *pos, *end;
struct ikev2_payloads pl;
wpa_printf(MSG_MSGDUMP, "IKEV2: Received message (len %lu)",
(unsigned long) wpabuf_len(buf));
if (wpabuf_len(buf) < sizeof(*hdr)) {
wpa_printf(MSG_INFO, "IKEV2: Too short frame to include HDR");
return -1;
}
hdr = (const struct ikev2_hdr *) wpabuf_head(buf);
end = wpabuf_head_u8(buf) + wpabuf_len(buf);
message_id = WPA_GET_BE32(hdr->message_id);
length = WPA_GET_BE32(hdr->length);
wpa_hexdump(MSG_DEBUG, "IKEV2: IKE_SA Initiator's SPI",
hdr->i_spi, IKEV2_SPI_LEN);
wpa_hexdump(MSG_DEBUG, "IKEV2: IKE_SA Initiator's SPI",
hdr->r_spi, IKEV2_SPI_LEN);
wpa_printf(MSG_DEBUG, "IKEV2: Next Payload: %u Version: 0x%x "
"Exchange Type: %u",
hdr->next_payload, hdr->version, hdr->exchange_type);
wpa_printf(MSG_DEBUG, "IKEV2: Message ID: %u Length: %u",
message_id, length);
if (hdr->version != IKEV2_VERSION) {
wpa_printf(MSG_INFO, "IKEV2: Unsupported HDR version 0x%x "
"(expected 0x%x)", hdr->version, IKEV2_VERSION);
return -1;
}
if (length != wpabuf_len(buf)) {
wpa_printf(MSG_INFO, "IKEV2: Invalid length (HDR: %lu != "
"RX: %lu)", (unsigned long) length,
(unsigned long) wpabuf_len(buf));
return -1;
}
if (ikev2_validate_rx_state(data, hdr->exchange_type, message_id) < 0)
return -1;
if ((hdr->flags & (IKEV2_HDR_INITIATOR | IKEV2_HDR_RESPONSE)) !=
IKEV2_HDR_RESPONSE) {
wpa_printf(MSG_INFO, "IKEV2: Unexpected Flags value 0x%x",
hdr->flags);
return -1;
}
if (data->state != SA_INIT) {
if (os_memcmp(data->i_spi, hdr->i_spi, IKEV2_SPI_LEN) != 0) {
wpa_printf(MSG_INFO, "IKEV2: Unexpected IKE_SA "
"Initiator's SPI");
return -1;
}
if (os_memcmp(data->r_spi, hdr->r_spi, IKEV2_SPI_LEN) != 0) {
wpa_printf(MSG_INFO, "IKEV2: Unexpected IKE_SA "
"Responder's SPI");
return -1;
}
}
pos = (const u8 *) (hdr + 1);
if (ikev2_parse_payloads(&pl, hdr->next_payload, pos, end) < 0)
return -1;
switch (data->state) {
case SA_INIT:
if (ikev2_process_sa_init(data, hdr, &pl) < 0)
return -1;
wpabuf_free(data->r_sign_msg);
data->r_sign_msg = wpabuf_dup(buf);
break;
case SA_AUTH:
if (ikev2_process_sa_auth(data, hdr, &pl) < 0)
return -1;
break;
case CHILD_SA:
case IKEV2_DONE:
break;
}
return 0;
}
static void ikev2_build_hdr(struct ikev2_initiator_data *data,
struct wpabuf *msg, u8 exchange_type,
u8 next_payload, u32 message_id)
{
struct ikev2_hdr *hdr;
wpa_printf(MSG_DEBUG, "IKEV2: Adding HDR");
/* HDR - RFC 4306, Sect. 3.1 */
hdr = wpabuf_put(msg, sizeof(*hdr));
os_memcpy(hdr->i_spi, data->i_spi, IKEV2_SPI_LEN);
os_memcpy(hdr->r_spi, data->r_spi, IKEV2_SPI_LEN);
hdr->next_payload = next_payload;
hdr->version = IKEV2_VERSION;
hdr->exchange_type = exchange_type;
hdr->flags = IKEV2_HDR_INITIATOR;
WPA_PUT_BE32(hdr->message_id, message_id);
}
static int ikev2_build_sai(struct ikev2_initiator_data *data,
struct wpabuf *msg, u8 next_payload)
{
struct ikev2_payload_hdr *phdr;
size_t plen;
struct ikev2_proposal *p;
struct ikev2_transform *t;
wpa_printf(MSG_DEBUG, "IKEV2: Adding SAi payload");
/* SAi1 - RFC 4306, Sect. 2.7 and 3.3 */
phdr = wpabuf_put(msg, sizeof(*phdr));
phdr->next_payload = next_payload;
phdr->flags = 0;
/* TODO: support for multiple proposals */
p = wpabuf_put(msg, sizeof(*p));
p->proposal_num = data->proposal.proposal_num;
p->protocol_id = IKEV2_PROTOCOL_IKE;
p->num_transforms = 4;
t = wpabuf_put(msg, sizeof(*t));
t->type = 3;
t->transform_type = IKEV2_TRANSFORM_ENCR;
WPA_PUT_BE16(t->transform_id, data->proposal.encr);
if (data->proposal.encr == ENCR_AES_CBC) {
/* Transform Attribute: Key Len = 128 bits */
wpabuf_put_be16(msg, 0x800e); /* AF=1, AttrType=14 */
wpabuf_put_be16(msg, 128); /* 128-bit key */
}
plen = (u8 *) wpabuf_put(msg, 0) - (u8 *) t;
WPA_PUT_BE16(t->transform_length, plen);
t = wpabuf_put(msg, sizeof(*t));
t->type = 3;
WPA_PUT_BE16(t->transform_length, sizeof(*t));
t->transform_type = IKEV2_TRANSFORM_PRF;
WPA_PUT_BE16(t->transform_id, data->proposal.prf);
t = wpabuf_put(msg, sizeof(*t));
t->type = 3;
WPA_PUT_BE16(t->transform_length, sizeof(*t));
t->transform_type = IKEV2_TRANSFORM_INTEG;
WPA_PUT_BE16(t->transform_id, data->proposal.integ);
t = wpabuf_put(msg, sizeof(*t));
WPA_PUT_BE16(t->transform_length, sizeof(*t));
t->transform_type = IKEV2_TRANSFORM_DH;
WPA_PUT_BE16(t->transform_id, data->proposal.dh);
plen = (u8 *) wpabuf_put(msg, 0) - (u8 *) p;
WPA_PUT_BE16(p->proposal_length, plen);
plen = (u8 *) wpabuf_put(msg, 0) - (u8 *) phdr;
WPA_PUT_BE16(phdr->payload_length, plen);
return 0;
}
static int ikev2_build_kei(struct ikev2_initiator_data *data,
struct wpabuf *msg, u8 next_payload)
{
struct ikev2_payload_hdr *phdr;
size_t plen;
struct wpabuf *pv;
wpa_printf(MSG_DEBUG, "IKEV2: Adding KEi payload");
data->dh = dh_groups_get(data->proposal.dh);
pv = dh_init(data->dh, &data->i_dh_private);
if (pv == NULL) {
wpa_printf(MSG_DEBUG, "IKEV2: Failed to initialize DH");
return -1;
}
/* KEi - RFC 4306, Sect. 3.4 */
phdr = wpabuf_put(msg, sizeof(*phdr));
phdr->next_payload = next_payload;
phdr->flags = 0;
wpabuf_put_be16(msg, data->proposal.dh); /* DH Group # */
wpabuf_put(msg, 2); /* RESERVED */
/*
* RFC 4306, Sect. 3.4: possible zero padding for public value to
* match the length of the prime.
*/
wpabuf_put(msg, data->dh->prime_len - wpabuf_len(pv));
wpabuf_put_buf(msg, pv);
wpabuf_free(pv);
plen = (u8 *) wpabuf_put(msg, 0) - (u8 *) phdr;
WPA_PUT_BE16(phdr->payload_length, plen);
return 0;
}
static int ikev2_build_ni(struct ikev2_initiator_data *data,
struct wpabuf *msg, u8 next_payload)
{
struct ikev2_payload_hdr *phdr;
size_t plen;
wpa_printf(MSG_DEBUG, "IKEV2: Adding Ni payload");
/* Ni - RFC 4306, Sect. 3.9 */
phdr = wpabuf_put(msg, sizeof(*phdr));
phdr->next_payload = next_payload;
phdr->flags = 0;
wpabuf_put_data(msg, data->i_nonce, data->i_nonce_len);
plen = (u8 *) wpabuf_put(msg, 0) - (u8 *) phdr;
WPA_PUT_BE16(phdr->payload_length, plen);
return 0;
}
static int ikev2_build_idi(struct ikev2_initiator_data *data,
struct wpabuf *msg, u8 next_payload)
{
struct ikev2_payload_hdr *phdr;
size_t plen;
wpa_printf(MSG_DEBUG, "IKEV2: Adding IDi payload");
if (data->IDi == NULL) {
wpa_printf(MSG_INFO, "IKEV2: No IDi available");
return -1;
}
/* IDi - RFC 4306, Sect. 3.5 */
phdr = wpabuf_put(msg, sizeof(*phdr));
phdr->next_payload = next_payload;
phdr->flags = 0;
wpabuf_put_u8(msg, ID_KEY_ID);
wpabuf_put(msg, 3); /* RESERVED */
wpabuf_put_data(msg, data->IDi, data->IDi_len);
plen = (u8 *) wpabuf_put(msg, 0) - (u8 *) phdr;
WPA_PUT_BE16(phdr->payload_length, plen);
return 0;
}
static int ikev2_build_auth(struct ikev2_initiator_data *data,
struct wpabuf *msg, u8 next_payload)
{
struct ikev2_payload_hdr *phdr;
size_t plen;
const struct ikev2_prf_alg *prf;
wpa_printf(MSG_DEBUG, "IKEV2: Adding AUTH payload");
prf = ikev2_get_prf(data->proposal.prf);
if (prf == NULL)
return -1;
/* Authentication - RFC 4306, Sect. 3.8 */
phdr = wpabuf_put(msg, sizeof(*phdr));
phdr->next_payload = next_payload;
phdr->flags = 0;
wpabuf_put_u8(msg, AUTH_SHARED_KEY_MIC);
wpabuf_put(msg, 3); /* RESERVED */
/* msg | Nr | prf(SK_pi,IDi') */
if (ikev2_derive_auth_data(data->proposal.prf, data->i_sign_msg,
data->IDi, data->IDi_len, ID_KEY_ID,
&data->keys, 1, data->shared_secret,
data->shared_secret_len,
data->r_nonce, data->r_nonce_len,
data->key_pad, data->key_pad_len,
wpabuf_put(msg, prf->hash_len)) < 0) {
wpa_printf(MSG_INFO, "IKEV2: Could not derive AUTH data");
return -1;
}
wpabuf_free(data->i_sign_msg);
data->i_sign_msg = NULL;
plen = (u8 *) wpabuf_put(msg, 0) - (u8 *) phdr;
WPA_PUT_BE16(phdr->payload_length, plen);
return 0;
}
static struct wpabuf * ikev2_build_sa_init(struct ikev2_initiator_data *data)
{
struct wpabuf *msg;
/* build IKE_SA_INIT: HDR, SAi, KEi, Ni */
if (os_get_random(data->i_spi, IKEV2_SPI_LEN))
return NULL;
wpa_hexdump(MSG_DEBUG, "IKEV2: IKE_SA Initiator's SPI",
data->i_spi, IKEV2_SPI_LEN);
data->i_nonce_len = IKEV2_NONCE_MIN_LEN;
if (random_get_bytes(data->i_nonce, data->i_nonce_len))
return NULL;
wpa_hexdump(MSG_DEBUG, "IKEV2: Ni", data->i_nonce, data->i_nonce_len);
msg = wpabuf_alloc(sizeof(struct ikev2_hdr) + 1000);
if (msg == NULL)
return NULL;
ikev2_build_hdr(data, msg, IKE_SA_INIT, IKEV2_PAYLOAD_SA, 0);
if (ikev2_build_sai(data, msg, IKEV2_PAYLOAD_KEY_EXCHANGE) ||
ikev2_build_kei(data, msg, IKEV2_PAYLOAD_NONCE) ||
ikev2_build_ni(data, msg, IKEV2_PAYLOAD_NO_NEXT_PAYLOAD)) {
wpabuf_free(msg);
return NULL;
}
ikev2_update_hdr(msg);
wpa_hexdump_buf(MSG_MSGDUMP, "IKEV2: Sending message (SA_INIT)", msg);
wpabuf_free(data->i_sign_msg);
data->i_sign_msg = wpabuf_dup(msg);
return msg;
}
static struct wpabuf * ikev2_build_sa_auth(struct ikev2_initiator_data *data)
{
struct wpabuf *msg, *plain;
const u8 *secret;
size_t secret_len;
secret = data->get_shared_secret(data->cb_ctx, data->IDr,
data->IDr_len, &secret_len);
if (secret == NULL) {
wpa_printf(MSG_INFO, "IKEV2: Could not get shared secret - "
"use fake value");
/* RFC 5106, Sect. 7:
* Use a random key to fake AUTH generation in order to prevent
* probing of user identities.
*/
data->unknown_user = 1;
os_free(data->shared_secret);
data->shared_secret = os_malloc(16);
if (data->shared_secret == NULL)
return NULL;
data->shared_secret_len = 16;
if (random_get_bytes(data->shared_secret, 16))
return NULL;
} else {
os_free(data->shared_secret);
data->shared_secret = os_malloc(secret_len);
if (data->shared_secret == NULL)
return NULL;
os_memcpy(data->shared_secret, secret, secret_len);
data->shared_secret_len = secret_len;
}
/* build IKE_SA_AUTH: HDR, SK {IDi, [CERT,] [CERTREQ,] AUTH} */
msg = wpabuf_alloc(sizeof(struct ikev2_hdr) + data->IDr_len + 1000);
if (msg == NULL)
return NULL;
ikev2_build_hdr(data, msg, IKE_SA_AUTH, IKEV2_PAYLOAD_ENCRYPTED, 1);
plain = wpabuf_alloc(data->IDr_len + 1000);
if (plain == NULL) {
wpabuf_free(msg);
return NULL;
}
if (ikev2_build_idi(data, plain, IKEV2_PAYLOAD_AUTHENTICATION) ||
ikev2_build_auth(data, plain, IKEV2_PAYLOAD_NO_NEXT_PAYLOAD) ||
ikev2_build_encrypted(data->proposal.encr, data->proposal.integ,
&data->keys, 1, msg, plain,
IKEV2_PAYLOAD_IDi)) {
wpabuf_free(plain);
wpabuf_free(msg);
return NULL;
}
wpabuf_free(plain);
wpa_hexdump_buf(MSG_MSGDUMP, "IKEV2: Sending message (SA_AUTH)", msg);
return msg;
}
struct wpabuf * ikev2_initiator_build(struct ikev2_initiator_data *data)
{
switch (data->state) {
case SA_INIT:
return ikev2_build_sa_init(data);
case SA_AUTH:
return ikev2_build_sa_auth(data);
case CHILD_SA:
return NULL;
case IKEV2_DONE:
return NULL;
}
return NULL;
}
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