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itlwm/itl80211/openbsd/net80211/ieee80211_crypto.c

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/*
* Copyright (C) 2020 钟先耀
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
/* $OpenBSD: ieee80211_crypto.c,v 1.75 2019/08/16 19:53:32 procter Exp $ */
/*-
* Copyright (c) 2008 Damien Bergamini <damien.bergamini@free.fr>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/endian.h>
#include <sys/errno.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_media.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <net80211/ieee80211_var.h>
#include <net80211/ieee80211_priv.h>
#include <crypto/arc4.h>
#include <crypto/md5.h>
#include <crypto/sha1.h>
#include <crypto/sha2.h>
#include <crypto/hmac.h>
#include <crypto/aes.h>
#include <crypto/cmac.h>
#include <crypto/key_wrap.h>
void ieee80211_prf(const u_int8_t *, size_t, const u_int8_t *, size_t,
const u_int8_t *, size_t, u_int8_t *, size_t);
void ieee80211_kdf(const u_int8_t *, size_t, const u_int8_t *, size_t,
const u_int8_t *, size_t, u_int8_t *, size_t);
void ieee80211_derive_pmkid(enum ieee80211_akm, const u_int8_t *,
const u_int8_t *, const u_int8_t *, u_int8_t *);
void
ieee80211_crypto_attach(struct _ifnet *ifp)
{
struct ieee80211com *ic = (struct ieee80211com *)ifp;
TAILQ_INIT(&ic->ic_pmksa);
if (ic->ic_caps & IEEE80211_C_RSN) {
ic->ic_rsnprotos = IEEE80211_PROTO_RSN;
ic->ic_rsnakms = IEEE80211_AKM_PSK;
ic->ic_rsnciphers = IEEE80211_CIPHER_CCMP;
ic->ic_rsngroupcipher = IEEE80211_CIPHER_CCMP;
ic->ic_rsngroupmgmtcipher = IEEE80211_CIPHER_BIP;
}
ic->ic_set_key = ieee80211_set_key;
ic->ic_delete_key = ieee80211_delete_key;
#ifndef IEEE80211_STA_ONLY
timeout_set(&ic->ic_tkip_micfail_timeout,
ieee80211_michael_mic_failure_timeout, ic);
#endif
}
void
ieee80211_crypto_detach(struct _ifnet *ifp)
{
XYLog("%s\n", __FUNCTION__);
struct ieee80211com *ic = (struct ieee80211com *)ifp;
struct ieee80211_pmk *pmk;
/* purge the PMKSA cache */
while ((pmk = TAILQ_FIRST(&ic->ic_pmksa)) != NULL) {
TAILQ_REMOVE(&ic->ic_pmksa, pmk, pmk_next);
explicit_bzero(pmk, sizeof(*pmk));
free(pmk);
}
/* clear all group keys from memory */
ieee80211_crypto_clear_groupkeys(ic);
/* clear pre-shared key from memory */
explicit_bzero(ic->ic_psk, IEEE80211_PMK_LEN);
#ifndef IEEE80211_STA_ONLY
timeout_del(&ic->ic_tkip_micfail_timeout);
timeout_free(&ic->ic_tkip_micfail_timeout);
#endif
}
void
ieee80211_crypto_clear_groupkeys(struct ieee80211com *ic)
{
int i;
for (i = 0; i < IEEE80211_GROUP_NKID; i++) {
struct ieee80211_key *k = &ic->ic_nw_keys[i];
if (k->k_cipher != IEEE80211_CIPHER_NONE)
(*ic->ic_delete_key)(ic, NULL, k);
explicit_bzero(k, sizeof(*k));
}
}
/*
* Return the length in bytes of a cipher suite key (see Table 60).
*/
int
ieee80211_cipher_keylen(enum ieee80211_cipher cipher)
{
switch (cipher) {
case IEEE80211_CIPHER_WEP40:
return 5;
case IEEE80211_CIPHER_TKIP:
return 32;
case IEEE80211_CIPHER_CCMP:
return 16;
case IEEE80211_CIPHER_WEP104:
return 13;
case IEEE80211_CIPHER_BIP:
return 16;
default: /* unknown cipher */
return 0;
}
}
int
ieee80211_set_key(struct ieee80211com *ic, struct ieee80211_node *ni,
struct ieee80211_key *k)
{
int error;
switch (k->k_cipher) {
case IEEE80211_CIPHER_WEP40:
case IEEE80211_CIPHER_WEP104:
error = ieee80211_wep_set_key(ic, k);
break;
case IEEE80211_CIPHER_TKIP:
error = ieee80211_tkip_set_key(ic, k);
break;
case IEEE80211_CIPHER_CCMP:
error = ieee80211_ccmp_set_key(ic, k);
break;
case IEEE80211_CIPHER_BIP:
error = ieee80211_bip_set_key(ic, k);
break;
default:
/* should not get there */
error = EINVAL;
}
if (error == 0)
k->k_flags |= IEEE80211_KEY_SWCRYPTO;
XYLog("%s kid=%d cipher=%d, error=%d\n", __FUNCTION__, k->k_id, k->k_cipher, error);
return error;
}
void
ieee80211_delete_key(struct ieee80211com *ic, struct ieee80211_node *ni,
struct ieee80211_key *k)
{
switch (k->k_cipher) {
case IEEE80211_CIPHER_WEP40:
case IEEE80211_CIPHER_WEP104:
ieee80211_wep_delete_key(ic, k);
break;
case IEEE80211_CIPHER_TKIP:
ieee80211_tkip_delete_key(ic, k);
break;
case IEEE80211_CIPHER_CCMP:
ieee80211_ccmp_delete_key(ic, k);
break;
case IEEE80211_CIPHER_BIP:
ieee80211_bip_delete_key(ic, k);
break;
default:
/* should not get there */
break;
}
explicit_bzero(k, sizeof(*k));
}
struct ieee80211_key *
ieee80211_get_txkey(struct ieee80211com *ic, const struct ieee80211_frame *wh,
struct ieee80211_node *ni)
{
int kid;
if ((ic->ic_flags & IEEE80211_F_RSNON) &&
!IEEE80211_IS_MULTICAST(wh->i_addr1) &&
ni->ni_rsncipher != IEEE80211_CIPHER_USEGROUP)
return &ni->ni_pairwise_key;
/* All other cases (including WEP) use a group key. */
if (ni->ni_flags & IEEE80211_NODE_MFP)
kid = ic->ic_igtk_kid;
else
kid = ic->ic_def_txkey;
return &ic->ic_nw_keys[kid];
}
struct ieee80211_key *
ieee80211_get_rxkey(struct ieee80211com *ic, mbuf_t m,
struct ieee80211_node *ni)
{
struct ieee80211_key *k = NULL;
struct ieee80211_frame *wh;
u_int16_t kid;
u_int8_t *ivp, *mmie;
int hdrlen;
wh = mtod(m, struct ieee80211_frame *);
if ((ic->ic_flags & IEEE80211_F_RSNON) &&
!IEEE80211_IS_MULTICAST(wh->i_addr1) &&
ni->ni_rsncipher != IEEE80211_CIPHER_USEGROUP) {
k = &ni->ni_pairwise_key;
} else if (!IEEE80211_IS_MULTICAST(wh->i_addr1) ||
(wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK) !=
IEEE80211_FC0_TYPE_MGT) {
/* retrieve group data key id from IV field */
hdrlen = ieee80211_get_hdrlen(wh);
/* check that IV field is present */
if (mbuf_len(m) < hdrlen + 4)
return NULL;
ivp = (u_int8_t *)wh + hdrlen;
kid = ivp[3] >> 6;
k = &ic->ic_nw_keys[kid];
} else {
/* retrieve integrity group key id from MMIE */
if (mbuf_len(m) < sizeof(*wh) + IEEE80211_MMIE_LEN)
return NULL;
/* it is assumed management frames are contiguous */
mmie = (u_int8_t *)wh + mbuf_len(m) - IEEE80211_MMIE_LEN;
/* check that MMIE is valid */
if (mmie[0] != IEEE80211_ELEMID_MMIE || mmie[1] != 16)
return NULL;
kid = LE_READ_2(&mmie[2]);
if (kid != 4 && kid != 5)
return NULL;
k = &ic->ic_nw_keys[kid];
}
return k;
}
mbuf_t
ieee80211_encrypt(struct ieee80211com *ic, mbuf_t m0,
struct ieee80211_key *k)
{
if ((k->k_flags & IEEE80211_KEY_SWCRYPTO) == 0) {
XYLog("%s: BUG! key unset for sw crypto. k_id: %d k_cipher: %d k_flags: %d\n", __FUNCTION__, k->k_id, k->k_cipher, k->k_flags);
mbuf_freem(m0);
return NULL;
}
XYLog("%s kid=%d cipher=%d\n", __FUNCTION__, k->k_id, k->k_cipher);
switch (k->k_cipher) {
case IEEE80211_CIPHER_WEP40:
case IEEE80211_CIPHER_WEP104:
m0 = ieee80211_wep_encrypt(ic, m0, k);
break;
case IEEE80211_CIPHER_TKIP:
m0 = ieee80211_tkip_encrypt(ic, m0, k);
break;
case IEEE80211_CIPHER_CCMP:
m0 = ieee80211_ccmp_encrypt(ic, m0, k);
break;
case IEEE80211_CIPHER_BIP:
m0 = ieee80211_bip_encap(ic, m0, k);
break;
default:
/* should not get there */
panic("invalid key cipher 0x%x", k->k_cipher);
}
return m0;
}
mbuf_t
ieee80211_decrypt(struct ieee80211com *ic, mbuf_t m0,
struct ieee80211_node *ni)
{
struct ieee80211_key *k;
/* find key for decryption */
k = ieee80211_get_rxkey(ic, m0, ni);
if (k == NULL || (k->k_flags & IEEE80211_KEY_SWCRYPTO) == 0) {
mbuf_freem(m0);
return NULL;
}
switch (k->k_cipher) {
case IEEE80211_CIPHER_WEP40:
case IEEE80211_CIPHER_WEP104:
m0 = ieee80211_wep_decrypt(ic, m0, k);
break;
case IEEE80211_CIPHER_TKIP:
m0 = ieee80211_tkip_decrypt(ic, m0, k);
break;
case IEEE80211_CIPHER_CCMP:
m0 = ieee80211_ccmp_decrypt(ic, m0, k);
break;
case IEEE80211_CIPHER_BIP:
m0 = ieee80211_bip_decap(ic, m0, k);
break;
default:
/* key not defined */
mbuf_freem(m0);
m0 = NULL;
}
return m0;
}
/*
* SHA1-based Pseudo-Random Function (see 8.5.1.1).
*/
void
ieee80211_prf(const u_int8_t *key, size_t key_len, const u_int8_t *label,
size_t label_len, const u_int8_t *context, size_t context_len,
u_int8_t *output, size_t len)
{
HMAC_SHA1_CTX ctx;
u_int8_t digest[SHA1_DIGEST_LENGTH];
u_int8_t count;
for (count = 0; len != 0; count++) {
HMAC_SHA1_Init(&ctx, key, key_len);
HMAC_SHA1_Update(&ctx, label, label_len);
HMAC_SHA1_Update(&ctx, context, context_len);
HMAC_SHA1_Update(&ctx, &count, 1);
if (len < SHA1_DIGEST_LENGTH) {
HMAC_SHA1_Final(digest, &ctx);
/* truncate HMAC-SHA1 to len bytes */
memcpy(output, digest, len);
break;
}
HMAC_SHA1_Final(output, &ctx);
output += SHA1_DIGEST_LENGTH;
len -= SHA1_DIGEST_LENGTH;
}
}
/*
* SHA256-based Key Derivation Function (see 8.5.1.5.2).
*/
void
ieee80211_kdf(const u_int8_t *key, size_t key_len, const u_int8_t *label,
size_t label_len, const u_int8_t *context, size_t context_len,
u_int8_t *output, size_t len)
{
HMAC_SHA256_CTX ctx;
u_int8_t digest[SHA256_DIGEST_LENGTH];
u_int16_t i, iter, length;
length = htole16(len * NBBY);
for (i = 1; len != 0; i++) {
HMAC_SHA256_Init(&ctx, key, key_len);
iter = htole16(i);
HMAC_SHA256_Update(&ctx, (u_int8_t *)&iter, sizeof iter);
HMAC_SHA256_Update(&ctx, label, label_len);
HMAC_SHA256_Update(&ctx, context, context_len);
HMAC_SHA256_Update(&ctx, (u_int8_t *)&length, sizeof length);
if (len < SHA256_DIGEST_LENGTH) {
HMAC_SHA256_Final(digest, &ctx);
/* truncate HMAC-SHA-256 to len bytes */
memcpy(output, digest, len);
break;
}
HMAC_SHA256_Final(output, &ctx);
output += SHA256_DIGEST_LENGTH;
len -= SHA256_DIGEST_LENGTH;
}
}
/*
* Derive Pairwise Transient Key (PTK) (see 8.5.1.2).
*/
void
ieee80211_derive_ptk(enum ieee80211_akm akm, const u_int8_t *pmk,
const u_int8_t *aa, const u_int8_t *spa, const u_int8_t *anonce,
const u_int8_t *snonce, struct ieee80211_ptk *ptk)
{
void (*kdf)(const u_int8_t *, size_t, const u_int8_t *, size_t,
const u_int8_t *, size_t, u_int8_t *, size_t);
u_int8_t buf[2 * IEEE80211_ADDR_LEN + 2 * EAPOL_KEY_NONCE_LEN];
int ret;
/* Min(AA,SPA) || Max(AA,SPA) */
ret = memcmp(aa, spa, IEEE80211_ADDR_LEN) < 0;
memcpy(&buf[ 0], ret ? aa : spa, IEEE80211_ADDR_LEN);
memcpy(&buf[ 6], ret ? spa : aa, IEEE80211_ADDR_LEN);
/* Min(ANonce,SNonce) || Max(ANonce,SNonce) */
ret = memcmp(anonce, snonce, EAPOL_KEY_NONCE_LEN) < 0;
memcpy(&buf[12], ret ? anonce : snonce, EAPOL_KEY_NONCE_LEN);
memcpy(&buf[44], ret ? snonce : anonce, EAPOL_KEY_NONCE_LEN);
kdf = ieee80211_is_sha256_akm(akm) ? ieee80211_kdf : ieee80211_prf;
(*kdf)(pmk, IEEE80211_PMK_LEN, (const u_int8_t *)"Pairwise key expansion", 23,
buf, sizeof buf, (u_int8_t *)ptk, sizeof(*ptk));
}
static void
ieee80211_pmkid_sha1(const u_int8_t *pmk, const u_int8_t *aa,
const u_int8_t *spa, u_int8_t *pmkid)
{
HMAC_SHA1_CTX ctx;
u_int8_t digest[SHA1_DIGEST_LENGTH];
HMAC_SHA1_Init(&ctx, pmk, IEEE80211_PMK_LEN);
HMAC_SHA1_Update(&ctx, (const u_int8_t *)"PMK Name", 8);
HMAC_SHA1_Update(&ctx, aa, IEEE80211_ADDR_LEN);
HMAC_SHA1_Update(&ctx, spa, IEEE80211_ADDR_LEN);
HMAC_SHA1_Final(digest, &ctx);
/* use the first 128 bits of HMAC-SHA1 */
memcpy(pmkid, digest, IEEE80211_PMKID_LEN);
}
static void
ieee80211_pmkid_sha256(const u_int8_t *pmk, const u_int8_t *aa,
const u_int8_t *spa, u_int8_t *pmkid)
{
HMAC_SHA256_CTX ctx;
u_int8_t digest[SHA256_DIGEST_LENGTH];
HMAC_SHA256_Init(&ctx, pmk, IEEE80211_PMK_LEN);
HMAC_SHA256_Update(&ctx, (uint8_t *)"PMK Name", 8);
HMAC_SHA256_Update(&ctx, aa, IEEE80211_ADDR_LEN);
HMAC_SHA256_Update(&ctx, spa, IEEE80211_ADDR_LEN);
HMAC_SHA256_Final(digest, &ctx);
/* use the first 128 bits of HMAC-SHA-256 */
memcpy(pmkid, digest, IEEE80211_PMKID_LEN);
}
/*
* Derive Pairwise Master Key Identifier (PMKID) (see 8.5.1.2).
*/
void
ieee80211_derive_pmkid(enum ieee80211_akm akm, const u_int8_t *pmk,
const u_int8_t *aa, const u_int8_t *spa, u_int8_t *pmkid)
{
if (ieee80211_is_sha256_akm(akm))
ieee80211_pmkid_sha256(pmk, aa, spa, pmkid);
else
ieee80211_pmkid_sha1(pmk, aa, spa, pmkid);
}
typedef union _ANY_CTX {
HMAC_MD5_CTX md5;
HMAC_SHA1_CTX sha1;
AES_CMAC_CTX cmac;
} ANY_CTX;
/*
* Compute the Key MIC field of an EAPOL-Key frame using the specified Key
* Confirmation Key (KCK). The hash function can be HMAC-MD5, HMAC-SHA1
* or AES-128-CMAC depending on the EAPOL-Key Key Descriptor Version.
*/
void
ieee80211_eapol_key_mic(struct ieee80211_eapol_key *key, const u_int8_t *kck)
{
XYLog("%s\n", __FUNCTION__);
u_int8_t digest[SHA1_DIGEST_LENGTH];
ANY_CTX ctx; /* XXX off stack? */
u_int len;
len = BE_READ_2(key->len) + 4;
switch (BE_READ_2(key->info) & EAPOL_KEY_VERSION_MASK) {
case EAPOL_KEY_DESC_V1:
HMAC_MD5_Init(&ctx.md5, kck, 16);
HMAC_MD5_Update(&ctx.md5, (u_int8_t *)key, len);
HMAC_MD5_Final(key->mic, &ctx.md5);
break;
case EAPOL_KEY_DESC_V2:
HMAC_SHA1_Init(&ctx.sha1, kck, 16);
HMAC_SHA1_Update(&ctx.sha1, (u_int8_t *)key, len);
HMAC_SHA1_Final(digest, &ctx.sha1);
/* truncate HMAC-SHA1 to its 128 MSBs */
memcpy(key->mic, digest, EAPOL_KEY_MIC_LEN);
break;
case EAPOL_KEY_DESC_V3:
AES_CMAC_Init(&ctx.cmac);
AES_CMAC_SetKey(&ctx.cmac, kck);
AES_CMAC_Update(&ctx.cmac, (u_int8_t *)key, len);
AES_CMAC_Final(key->mic, &ctx.cmac);
break;
}
}
/*
* Check the MIC of a received EAPOL-Key frame using the specified Key
* Confirmation Key (KCK).
*/
int
ieee80211_eapol_key_check_mic(struct ieee80211_eapol_key *key,
const u_int8_t *kck)
{
u_int8_t mic[EAPOL_KEY_MIC_LEN];
memcpy(mic, key->mic, EAPOL_KEY_MIC_LEN);
memset(key->mic, 0, EAPOL_KEY_MIC_LEN);
ieee80211_eapol_key_mic(key, kck);
return timingsafe_bcmp(key->mic, mic, EAPOL_KEY_MIC_LEN) != 0;
}
#ifndef IEEE80211_STA_ONLY
/*
* Encrypt the Key Data field of an EAPOL-Key frame using the specified Key
* Encryption Key (KEK). The encryption algorithm can be either ARC4 or
* AES Key Wrap depending on the EAPOL-Key Key Descriptor Version.
*/
void
ieee80211_eapol_key_encrypt(struct ieee80211com *ic,
struct ieee80211_eapol_key *key, const u_int8_t *kek)
{
union {
struct rc4_ctx rc4;
aes_key_wrap_ctx aes;
} ctx; /* XXX off stack? */
u_int8_t keybuf[EAPOL_KEY_IV_LEN + 16];
u_int16_t len, info;
u_int8_t *data;
int n;
len = BE_READ_2(key->paylen);
info = BE_READ_2(key->info);
data = (u_int8_t *)(key + 1);
switch (info & EAPOL_KEY_VERSION_MASK) {
case EAPOL_KEY_DESC_V1:
/* set IV to the lower 16 octets of our global key counter */
memcpy(key->iv, ic->ic_globalcnt + 16, 16);
/* increment our global key counter (256-bit, big-endian) */
for (n = 31; n >= 0 && ++ic->ic_globalcnt[n] == 0; n--);
/* concatenate the EAPOL-Key IV field and the KEK */
memcpy(keybuf, key->iv, EAPOL_KEY_IV_LEN);
memcpy(keybuf + EAPOL_KEY_IV_LEN, kek, 16);
rc4_keysetup(&ctx.rc4, keybuf, sizeof keybuf);
/* discard the first 256 octets of the ARC4 key stream */
rc4_skip(&ctx.rc4, RC4STATE);
rc4_crypt(&ctx.rc4, data, data, len);
break;
case EAPOL_KEY_DESC_V2:
case EAPOL_KEY_DESC_V3:
if (len < 16 || (len & 7) != 0) {
/* insert padding */
n = (len < 16) ? 16 - len : 8 - (len & 7);
data[len++] = IEEE80211_ELEMID_VENDOR;
memset(&data[len], 0, n - 1);
len += n - 1;
}
aes_key_wrap_set_key_wrap_only(&ctx.aes, kek, 16);
aes_key_wrap(&ctx.aes, data, len / 8, data);
len += 8; /* AES Key Wrap adds 8 bytes */
/* update key data length */
BE_WRITE_2(key->paylen, len);
/* update packet body length */
BE_WRITE_2(key->len, sizeof(*key) + len - 4);
break;
}
}
#endif /* IEEE80211_STA_ONLY */
/*
* Decrypt the Key Data field of an EAPOL-Key frame using the specified Key
* Encryption Key (KEK). The encryption algorithm can be either ARC4 or
* AES Key Wrap depending on the EAPOL-Key Key Descriptor Version.
*/
int
ieee80211_eapol_key_decrypt(struct ieee80211_eapol_key *key,
const u_int8_t *kek)
{
union {
struct rc4_ctx rc4;
aes_key_wrap_ctx aes;
} ctx; /* XXX off stack? */
u_int8_t keybuf[EAPOL_KEY_IV_LEN + 16];
u_int16_t len, info;
u_int8_t *data;
len = BE_READ_2(key->paylen);
info = BE_READ_2(key->info);
data = (u_int8_t *)(key + 1);
switch (info & EAPOL_KEY_VERSION_MASK) {
case EAPOL_KEY_DESC_V1:
/* concatenate the EAPOL-Key IV field and the KEK */
memcpy(keybuf, key->iv, EAPOL_KEY_IV_LEN);
memcpy(keybuf + EAPOL_KEY_IV_LEN, kek, 16);
rc4_keysetup(&ctx.rc4, keybuf, sizeof keybuf);
/* discard the first 256 octets of the ARC4 key stream */
rc4_skip(&ctx.rc4, RC4STATE);
rc4_crypt(&ctx.rc4, data, data, len);
return 0;
case EAPOL_KEY_DESC_V2:
case EAPOL_KEY_DESC_V3:
/* Key Data Length must be a multiple of 8 */
if (len < 16 + 8 || (len & 7) != 0)
return 1;
len -= 8; /* AES Key Wrap adds 8 bytes */
aes_key_wrap_set_key(&ctx.aes, kek, 16);
return aes_key_unwrap(&ctx.aes, data, data, len / 8);
}
return 1; /* unknown Key Descriptor Version */
}
/*
* Add a PMK entry to the PMKSA cache.
*/
struct ieee80211_pmk *
ieee80211_pmksa_add(struct ieee80211com *ic, enum ieee80211_akm akm,
const u_int8_t *macaddr, const u_int8_t *key, u_int32_t lifetime)
{
struct ieee80211_pmk *pmk;
/* check if an entry already exists for this (STA,AKMP) */
TAILQ_FOREACH(pmk, &ic->ic_pmksa, pmk_next) {
if (pmk->pmk_akm == akm &&
IEEE80211_ADDR_EQ(pmk->pmk_macaddr, macaddr))
break;
}
if (pmk == NULL) {
/* allocate a new PMKSA entry */
if ((pmk = (struct ieee80211_pmk *)malloc(sizeof(*pmk), 0, 0)) == NULL)
return NULL;
pmk->pmk_akm = akm;
IEEE80211_ADDR_COPY(pmk->pmk_macaddr, macaddr);
TAILQ_INSERT_TAIL(&ic->ic_pmksa, pmk, pmk_next);
}
memcpy(pmk->pmk_key, key, IEEE80211_PMK_LEN);
pmk->pmk_lifetime = lifetime; /* XXX not used yet */
#ifndef IEEE80211_STA_ONLY
if (ic->ic_opmode == IEEE80211_M_HOSTAP) {
ieee80211_derive_pmkid(pmk->pmk_akm, pmk->pmk_key,
ic->ic_myaddr, macaddr, pmk->pmk_pmkid);
} else
#endif
{
ieee80211_derive_pmkid(pmk->pmk_akm, pmk->pmk_key,
macaddr, ic->ic_myaddr, pmk->pmk_pmkid);
}
return pmk;
}
/*
* Check if we have a cached PMK entry for the specified node and PMKID.
*/
struct ieee80211_pmk *
ieee80211_pmksa_find(struct ieee80211com *ic, struct ieee80211_node *ni,
const u_int8_t *pmkid)
{
struct ieee80211_pmk *pmk;
TAILQ_FOREACH(pmk, &ic->ic_pmksa, pmk_next) {
if (pmk->pmk_akm == ni->ni_rsnakms &&
IEEE80211_ADDR_EQ(pmk->pmk_macaddr, ni->ni_macaddr) &&
(pmkid == NULL ||
memcmp(pmk->pmk_pmkid, pmkid, IEEE80211_PMKID_LEN) == 0))
break;
}
return pmk;
}
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