602 lines
17 KiB
C
602 lines
17 KiB
C
/*-
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* Copyright (c) 2001 Atsushi Onoe
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* Copyright (c) 2002-2005 Sam Leffler, Errno Consulting
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL") version 2 as published by the Free
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* Software Foundation.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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/*
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* IEEE 802.11 generic crypto support.
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*/
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#include <sys/param.h>
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#include <sys/mbuf.h>
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#include <sys/socket.h>
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#include <net/if.h>
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#include <net/if_media.h>
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#include <net/ethernet.h> /* XXX ETHER_HDR_LEN */
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#include <net80211/ieee80211_var.h>
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/*
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* Table of registered cipher modules.
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*/
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static const struct ieee80211_cipher *ciphers[IEEE80211_CIPHER_MAX];
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static int _ieee80211_crypto_delkey(struct ieee80211com *,
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struct ieee80211_key *);
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/*
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* Default "null" key management routines.
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*/
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static int
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null_key_alloc(struct ieee80211com *ic, const struct ieee80211_key *k,
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ieee80211_keyix *keyix, ieee80211_keyix *rxkeyix)
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{
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if (!(&ic->ic_nw_keys[0] <= k &&
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k < &ic->ic_nw_keys[IEEE80211_WEP_NKID])) {
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/*
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* Not in the global key table, the driver should handle this
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* by allocating a slot in the h/w key table/cache. In
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* lieu of that return key slot 0 for any unicast key
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* request. We disallow the request if this is a group key.
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* This default policy does the right thing for legacy hardware
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* with a 4 key table. It also handles devices that pass
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* packets through untouched when marked with the WEP bit
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* and key index 0.
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*/
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if (k->wk_flags & IEEE80211_KEY_GROUP)
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return 0;
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*keyix = 0; /* NB: use key index 0 for ucast key */
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} else {
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*keyix = k - ic->ic_nw_keys;
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}
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*rxkeyix = IEEE80211_KEYIX_NONE; /* XXX maybe *keyix? */
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return 1;
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}
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static int
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null_key_delete(struct ieee80211com *ic, const struct ieee80211_key *k)
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{
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return 1;
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}
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static int
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null_key_set(struct ieee80211com *ic, const struct ieee80211_key *k,
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const u_int8_t mac[IEEE80211_ADDR_LEN])
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{
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return 1;
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}
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static void null_key_update(struct ieee80211com *ic) {}
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/*
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* Write-arounds for common operations.
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*/
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static __inline void
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cipher_detach(struct ieee80211_key *key)
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{
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key->wk_cipher->ic_detach(key);
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}
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static __inline void *
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cipher_attach(struct ieee80211com *ic, struct ieee80211_key *key)
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{
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return key->wk_cipher->ic_attach(ic, key);
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}
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/*
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* Wrappers for driver key management methods.
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*/
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static __inline int
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dev_key_alloc(struct ieee80211com *ic,
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const struct ieee80211_key *key,
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ieee80211_keyix *keyix, ieee80211_keyix *rxkeyix)
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{
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return ic->ic_crypto.cs_key_alloc(ic, key, keyix, rxkeyix);
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}
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static __inline int
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dev_key_delete(struct ieee80211com *ic,
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const struct ieee80211_key *key)
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{
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return ic->ic_crypto.cs_key_delete(ic, key);
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}
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static __inline int
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dev_key_set(struct ieee80211com *ic, const struct ieee80211_key *key,
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const u_int8_t mac[IEEE80211_ADDR_LEN])
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{
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return ic->ic_crypto.cs_key_set(ic, key, mac);
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}
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/*
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* Setup crypto support.
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*/
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void
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ieee80211_crypto_attach(struct ieee80211com *ic)
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{
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struct ieee80211_crypto_state *cs = &ic->ic_crypto;
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int i;
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/* NB: we assume everything is pre-zero'd */
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cs->cs_def_txkey = IEEE80211_KEYIX_NONE;
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cs->cs_max_keyix = IEEE80211_WEP_NKID;
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ciphers[IEEE80211_CIPHER_NONE] = &ieee80211_cipher_none;
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for (i = 0; i < IEEE80211_WEP_NKID; i++)
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ieee80211_crypto_resetkey(ic, &cs->cs_nw_keys[i],
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IEEE80211_KEYIX_NONE);
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/*
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* Initialize the driver key support routines to noop entries.
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* This is useful especially for the cipher test modules.
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*/
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cs->cs_key_alloc = null_key_alloc;
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cs->cs_key_set = null_key_set;
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cs->cs_key_delete = null_key_delete;
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cs->cs_key_update_begin = null_key_update;
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cs->cs_key_update_end = null_key_update;
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}
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/*
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* Teardown crypto support.
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*/
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void
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ieee80211_crypto_detach(struct ieee80211com *ic)
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{
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ieee80211_crypto_delglobalkeys(ic);
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}
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/*
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* Register a crypto cipher module.
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*/
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void
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ieee80211_crypto_register(const struct ieee80211_cipher *cip)
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{
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if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
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printf("%s: cipher %s has an invalid cipher index %u\n",
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__func__, cip->ic_name, cip->ic_cipher);
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return;
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}
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if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) {
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printf("%s: cipher %s registered with a different template\n",
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__func__, cip->ic_name);
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return;
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}
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ciphers[cip->ic_cipher] = cip;
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}
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/*
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* Unregister a crypto cipher module.
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*/
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void
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ieee80211_crypto_unregister(const struct ieee80211_cipher *cip)
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{
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if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
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printf("%s: cipher %s has an invalid cipher index %u\n",
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__func__, cip->ic_name, cip->ic_cipher);
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return;
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}
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if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) {
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printf("%s: cipher %s registered with a different template\n",
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__func__, cip->ic_name);
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return;
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}
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/* NB: don't complain about not being registered */
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/* XXX disallow if references */
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ciphers[cip->ic_cipher] = NULL;
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}
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int
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ieee80211_crypto_available(u_int cipher)
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{
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return cipher < IEEE80211_CIPHER_MAX && ciphers[cipher] != NULL;
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}
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/* XXX well-known names! */
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static const char *cipher_modnames[] = {
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"wlan_wep", /* IEEE80211_CIPHER_WEP */
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"wlan_tkip", /* IEEE80211_CIPHER_TKIP */
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"wlan_aes_ocb", /* IEEE80211_CIPHER_AES_OCB */
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"wlan_ccmp", /* IEEE80211_CIPHER_AES_CCM */
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"wlan_ckip", /* IEEE80211_CIPHER_CKIP */
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};
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/*
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* Establish a relationship between the specified key and cipher
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* and, if necessary, allocate a hardware index from the driver.
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* Note that when a fixed key index is required it must be specified
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* and we blindly assign it w/o consulting the driver (XXX).
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*
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* This must be the first call applied to a key; all the other key
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* routines assume wk_cipher is setup.
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*
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* Locking must be handled by the caller using:
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* ieee80211_key_update_begin(ic);
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* ieee80211_key_update_end(ic);
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*/
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int
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ieee80211_crypto_newkey(struct ieee80211com *ic,
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int cipher, int flags, struct ieee80211_key *key)
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{
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#define N(a) (sizeof(a) / sizeof(a[0]))
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const struct ieee80211_cipher *cip;
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ieee80211_keyix keyix, rxkeyix;
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void *keyctx;
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int oflags;
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/*
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* Validate cipher and set reference to cipher routines.
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*/
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if (cipher >= IEEE80211_CIPHER_MAX) {
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IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
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"%s: invalid cipher %u\n", __func__, cipher);
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ic->ic_stats.is_crypto_badcipher++;
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return 0;
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}
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cip = ciphers[cipher];
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if (cip == NULL) {
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/*
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* Auto-load cipher module if we have a well-known name
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* for it. It might be better to use string names rather
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* than numbers and craft a module name based on the cipher
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* name; e.g. wlan_cipher_<cipher-name>.
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*/
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if (cipher < N(cipher_modnames)) {
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IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
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"%s: unregistered cipher %u, load module %s\n",
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__func__, cipher, cipher_modnames[cipher]);
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ieee80211_load_module(cipher_modnames[cipher]);
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/*
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* If cipher module loaded it should immediately
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* call ieee80211_crypto_register which will fill
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* in the entry in the ciphers array.
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*/
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cip = ciphers[cipher];
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}
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if (cip == NULL) {
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IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
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"%s: unable to load cipher %u, module %s\n",
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__func__, cipher,
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cipher < N(cipher_modnames) ?
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cipher_modnames[cipher] : "<unknown>");
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ic->ic_stats.is_crypto_nocipher++;
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return 0;
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}
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}
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oflags = key->wk_flags;
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flags &= IEEE80211_KEY_COMMON;
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/*
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* If the hardware does not support the cipher then
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* fallback to a host-based implementation.
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*/
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if ((ic->ic_caps & (1<<cipher)) == 0) {
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IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
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"%s: no h/w support for cipher %s, falling back to s/w\n",
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__func__, cip->ic_name);
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flags |= IEEE80211_KEY_SWCRYPT;
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}
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/*
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* Hardware TKIP with software MIC is an important
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* combination; we handle it by flagging each key,
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* the cipher modules honor it.
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*/
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if (cipher == IEEE80211_CIPHER_TKIP &&
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(ic->ic_caps & IEEE80211_C_TKIPMIC) == 0) {
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IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
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"%s: no h/w support for TKIP MIC, falling back to s/w\n",
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__func__);
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flags |= IEEE80211_KEY_SWMIC;
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}
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/*
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* Bind cipher to key instance. Note we do this
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* after checking the device capabilities so the
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* cipher module can optimize space usage based on
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* whether or not it needs to do the cipher work.
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*/
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if (key->wk_cipher != cip || key->wk_flags != flags) {
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again:
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/*
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* Fillin the flags so cipher modules can see s/w
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* crypto requirements and potentially allocate
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* different state and/or attach different method
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* pointers.
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*
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* XXX this is not right when s/w crypto fallback
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* fails and we try to restore previous state.
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*/
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key->wk_flags = flags;
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keyctx = cip->ic_attach(ic, key);
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if (keyctx == NULL) {
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IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
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"%s: unable to attach cipher %s\n",
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__func__, cip->ic_name);
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key->wk_flags = oflags; /* restore old flags */
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ic->ic_stats.is_crypto_attachfail++;
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return 0;
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}
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cipher_detach(key);
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key->wk_cipher = cip; /* XXX refcnt? */
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key->wk_private = keyctx;
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}
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/*
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* Commit to requested usage so driver can see the flags.
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*/
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key->wk_flags = flags;
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/*
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* Ask the driver for a key index if we don't have one.
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* Note that entries in the global key table always have
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* an index; this means it's safe to call this routine
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* for these entries just to setup the reference to the
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* cipher template. Note also that when using software
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* crypto we also call the driver to give us a key index.
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*/
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if (key->wk_keyix == IEEE80211_KEYIX_NONE) {
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if (!dev_key_alloc(ic, key, &keyix, &rxkeyix)) {
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/*
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* Driver has no room; fallback to doing crypto
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* in the host. We change the flags and start the
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* procedure over. If we get back here then there's
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* no hope and we bail. Note that this can leave
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* the key in a inconsistent state if the caller
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* continues to use it.
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*/
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if ((key->wk_flags & IEEE80211_KEY_SWCRYPT) == 0) {
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ic->ic_stats.is_crypto_swfallback++;
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IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
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"%s: no h/w resources for cipher %s, "
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"falling back to s/w\n", __func__,
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cip->ic_name);
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oflags = key->wk_flags;
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flags |= IEEE80211_KEY_SWCRYPT;
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if (cipher == IEEE80211_CIPHER_TKIP)
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flags |= IEEE80211_KEY_SWMIC;
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goto again;
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}
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ic->ic_stats.is_crypto_keyfail++;
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IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
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"%s: unable to setup cipher %s\n",
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__func__, cip->ic_name);
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return 0;
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}
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key->wk_keyix = keyix;
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key->wk_rxkeyix = rxkeyix;
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}
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return 1;
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#undef N
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}
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/*
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* Remove the key (no locking, for internal use).
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*/
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static int
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_ieee80211_crypto_delkey(struct ieee80211com *ic, struct ieee80211_key *key)
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{
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ieee80211_keyix keyix;
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KASSERT(key->wk_cipher != NULL, ("No cipher!"));
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IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
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"%s: %s keyix %u flags 0x%x rsc %ju tsc %ju len %u\n",
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__func__, key->wk_cipher->ic_name,
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key->wk_keyix, key->wk_flags,
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key->wk_keyrsc, key->wk_keytsc, key->wk_keylen);
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keyix = key->wk_keyix;
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if (keyix != IEEE80211_KEYIX_NONE) {
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/*
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* Remove hardware entry.
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*/
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/* XXX key cache */
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if (!dev_key_delete(ic, key)) {
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IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
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"%s: driver did not delete key index %u\n",
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__func__, keyix);
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ic->ic_stats.is_crypto_delkey++;
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/* XXX recovery? */
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}
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}
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cipher_detach(key);
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memset(key, 0, sizeof(*key));
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ieee80211_crypto_resetkey(ic, key, IEEE80211_KEYIX_NONE);
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return 1;
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}
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/*
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* Remove the specified key.
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*/
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int
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ieee80211_crypto_delkey(struct ieee80211com *ic, struct ieee80211_key *key)
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{
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int status;
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ieee80211_key_update_begin(ic);
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status = _ieee80211_crypto_delkey(ic, key);
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ieee80211_key_update_end(ic);
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return status;
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}
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/*
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* Clear the global key table.
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*/
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void
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ieee80211_crypto_delglobalkeys(struct ieee80211com *ic)
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{
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int i;
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ieee80211_key_update_begin(ic);
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for (i = 0; i < IEEE80211_WEP_NKID; i++)
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(void) _ieee80211_crypto_delkey(ic, &ic->ic_nw_keys[i]);
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ieee80211_key_update_end(ic);
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}
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/*
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* Set the contents of the specified key.
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*
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* Locking must be handled by the caller using:
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* ieee80211_key_update_begin(ic);
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* ieee80211_key_update_end(ic);
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*/
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int
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ieee80211_crypto_setkey(struct ieee80211com *ic, struct ieee80211_key *key,
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const u_int8_t macaddr[IEEE80211_ADDR_LEN])
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{
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const struct ieee80211_cipher *cip = key->wk_cipher;
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KASSERT(cip != NULL, ("No cipher!"));
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IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
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"%s: %s keyix %u flags 0x%x mac %s rsc %ju tsc %ju len %u\n",
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__func__, cip->ic_name, key->wk_keyix,
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key->wk_flags, ether_sprintf(macaddr),
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key->wk_keyrsc, key->wk_keytsc, key->wk_keylen);
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/*
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* Give cipher a chance to validate key contents.
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* XXX should happen before modifying state.
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*/
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if (!cip->ic_setkey(key)) {
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IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
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"%s: cipher %s rejected key index %u len %u flags 0x%x\n",
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__func__, cip->ic_name, key->wk_keyix,
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key->wk_keylen, key->wk_flags);
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ic->ic_stats.is_crypto_setkey_cipher++;
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return 0;
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}
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if (key->wk_keyix == IEEE80211_KEYIX_NONE) {
|
|
/* XXX nothing allocated, should not happen */
|
|
IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
|
|
"%s: no key index; should not happen!\n", __func__);
|
|
ic->ic_stats.is_crypto_setkey_nokey++;
|
|
return 0;
|
|
}
|
|
return dev_key_set(ic, key, macaddr);
|
|
}
|
|
|
|
/*
|
|
* Add privacy headers appropriate for the specified key.
|
|
*/
|
|
struct ieee80211_key *
|
|
ieee80211_crypto_encap(struct ieee80211com *ic,
|
|
struct ieee80211_node *ni, struct mbuf *m)
|
|
{
|
|
struct ieee80211_key *k;
|
|
struct ieee80211_frame *wh;
|
|
const struct ieee80211_cipher *cip;
|
|
u_int8_t keyid;
|
|
|
|
/*
|
|
* Multicast traffic always uses the multicast key.
|
|
* Otherwise if a unicast key is set we use that and
|
|
* it is always key index 0. When no unicast key is
|
|
* set we fall back to the default transmit key.
|
|
*/
|
|
wh = mtod(m, struct ieee80211_frame *);
|
|
if (IEEE80211_IS_MULTICAST(wh->i_addr1) ||
|
|
IEEE80211_KEY_UNDEFINED(&ni->ni_ucastkey)) {
|
|
if (ic->ic_def_txkey == IEEE80211_KEYIX_NONE) {
|
|
IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
|
|
"[%s] no default transmit key (%s) deftxkey %u\n",
|
|
ether_sprintf(wh->i_addr1), __func__,
|
|
ic->ic_def_txkey);
|
|
ic->ic_stats.is_tx_nodefkey++;
|
|
return NULL;
|
|
}
|
|
keyid = ic->ic_def_txkey;
|
|
k = &ic->ic_nw_keys[ic->ic_def_txkey];
|
|
} else {
|
|
keyid = 0;
|
|
k = &ni->ni_ucastkey;
|
|
}
|
|
cip = k->wk_cipher;
|
|
return (cip->ic_encap(k, m, keyid<<6) ? k : NULL);
|
|
}
|
|
|
|
/*
|
|
* Validate and strip privacy headers (and trailer) for a
|
|
* received frame that has the WEP/Privacy bit set.
|
|
*/
|
|
struct ieee80211_key *
|
|
ieee80211_crypto_decap(struct ieee80211com *ic,
|
|
struct ieee80211_node *ni, struct mbuf *m, int hdrlen)
|
|
{
|
|
#define IEEE80211_WEP_HDRLEN (IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN)
|
|
#define IEEE80211_WEP_MINLEN \
|
|
(sizeof(struct ieee80211_frame) + \
|
|
IEEE80211_WEP_HDRLEN + IEEE80211_WEP_CRCLEN)
|
|
struct ieee80211_key *k;
|
|
struct ieee80211_frame *wh;
|
|
const struct ieee80211_cipher *cip;
|
|
const u_int8_t *ivp;
|
|
u_int8_t keyid;
|
|
|
|
/* NB: this minimum size data frame could be bigger */
|
|
if (m->m_pkthdr.len < IEEE80211_WEP_MINLEN) {
|
|
IEEE80211_DPRINTF(ic, IEEE80211_MSG_ANY,
|
|
"%s: WEP data frame too short, len %u\n",
|
|
__func__, m->m_pkthdr.len);
|
|
ic->ic_stats.is_rx_tooshort++; /* XXX need unique stat? */
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Locate the key. If unicast and there is no unicast
|
|
* key then we fall back to the key id in the header.
|
|
* This assumes unicast keys are only configured when
|
|
* the key id in the header is meaningless (typically 0).
|
|
*/
|
|
wh = mtod(m, struct ieee80211_frame *);
|
|
ivp = mtod(m, const u_int8_t *) + hdrlen; /* XXX contig */
|
|
keyid = ivp[IEEE80211_WEP_IVLEN];
|
|
if (IEEE80211_IS_MULTICAST(wh->i_addr1) ||
|
|
IEEE80211_KEY_UNDEFINED(&ni->ni_ucastkey))
|
|
k = &ic->ic_nw_keys[keyid >> 6];
|
|
else
|
|
k = &ni->ni_ucastkey;
|
|
|
|
/*
|
|
* Insure crypto header is contiguous for all decap work.
|
|
*/
|
|
cip = k->wk_cipher;
|
|
if (m->m_len < hdrlen + cip->ic_header &&
|
|
(m = m_pullup(m, hdrlen + cip->ic_header)) == NULL) {
|
|
IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
|
|
"[%s] unable to pullup %s header\n",
|
|
ether_sprintf(wh->i_addr2), cip->ic_name);
|
|
ic->ic_stats.is_rx_wepfail++; /* XXX */
|
|
return 0;
|
|
}
|
|
|
|
return (cip->ic_decap(k, m, hdrlen) ? k : NULL);
|
|
#undef IEEE80211_WEP_MINLEN
|
|
#undef IEEE80211_WEP_HDRLEN
|
|
}
|