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madwifi/net80211/ieee80211_crypto.c

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/*-
* Copyright (c) 2001 Atsushi Onoe
* Copyright (c) 2002-2005 Sam Leffler, Errno Consulting
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $Id$
*/
#ifndef EXPORT_SYMTAB
#define EXPORT_SYMTAB
#endif
/*
* IEEE 802.11 generic crypto support.
*/
#ifndef AUTOCONF_INCLUDED
#include <linux/config.h>
#endif
#include <linux/version.h>
#include <linux/module.h>
#include <linux/kmod.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/random.h>
#include "if_ethersubr.h" /* for ETHER_HDR_LEN */
#include "if_media.h"
#include <net80211/ieee80211_var.h>
/*
* Table of registered cipher modules.
*/
static const struct ieee80211_cipher *ciphers[IEEE80211_CIPHER_MAX];
static int ieee80211_crypto_delkey_locked(struct ieee80211vap *,
struct ieee80211_key *, struct ieee80211_node *);
/*
* Default "null" key management routines.
*/
static ieee80211_keyix_t
null_key_alloc(struct ieee80211vap *vap, const struct ieee80211_key *k)
{
return IEEE80211_KEYIX_NONE;
}
static int
null_key_delete(struct ieee80211vap *vap, const struct ieee80211_key *k,
struct ieee80211_node *ni)
{
return 1;
}
static int
null_key_set(struct ieee80211vap *vap, const struct ieee80211_key *k,
const u_int8_t mac[IEEE80211_ADDR_LEN])
{
return 1;
}
static void null_key_update(struct ieee80211vap *vap)
{
}
#ifdef ATH_SUPERG_COMP
static void
null_comp_set(struct ieee80211vap *vap, struct ieee80211_node *ni,
int en)
{
}
#endif
/*
* Write-arounds for common operations.
*/
static __inline void
cipher_detach(struct ieee80211_key *key)
{
key->wk_cipher->ic_detach(key);
}
static __inline void *
cipher_attach(struct ieee80211vap *vap, struct ieee80211_key *key)
{
return key->wk_cipher->ic_attach(vap, key);
}
/*
* Wrappers for driver key management methods.
*/
static __inline ieee80211_keyix_t
dev_key_alloc(struct ieee80211vap *vap, const struct ieee80211_key *key)
{
return vap->iv_key_alloc(vap, key);
}
static __inline int
dev_key_delete(struct ieee80211vap *vap, const struct ieee80211_key *key,
struct ieee80211_node *ni)
{
return vap->iv_key_delete(vap, key, ni);
}
static __inline int
dev_key_set(struct ieee80211vap *vap, const struct ieee80211_key *key,
const u_int8_t mac[IEEE80211_ADDR_LEN])
{
return vap->iv_key_set(vap, key, mac);
}
#ifdef ATH_SUPERG_COMP
static __inline void
dev_comp_set(struct ieee80211vap *vap, struct ieee80211_node *ni, int en)
{
return vap->iv_comp_set(vap, ni, en);
}
#endif
/*
* Setup crypto support for a device/shared instance.
*/
void
ieee80211_crypto_attach(struct ieee80211com *ic)
{
/* NB: we assume everything is pre-zero'd */
ciphers[IEEE80211_CIPHER_NONE] = &ieee80211_cipher_none;
}
EXPORT_SYMBOL(ieee80211_crypto_attach);
/*
* Teardown crypto support.
*/
void
ieee80211_crypto_detach(struct ieee80211com *ic)
{
}
EXPORT_SYMBOL(ieee80211_crypto_detach);
/*
* Setup crypto support for a VAP.
*/
void
ieee80211_crypto_vattach(struct ieee80211vap *vap)
{
int i;
/* NB: We assume everything is pre-zeroed */
vap->iv_def_txkey = IEEE80211_KEYIX_NONE;
for (i = 0; i < IEEE80211_WEP_NKID; i++)
ieee80211_crypto_resetkey(vap, &vap->iv_nw_keys[i],
IEEE80211_KEYIX_NONE);
/*
* Initialize the driver key support routines to noop entries.
* This is useful especially for the cipher test modules.
*/
vap->iv_key_alloc = null_key_alloc;
vap->iv_key_set = null_key_set;
vap->iv_key_delete = null_key_delete;
vap->iv_key_update_begin = null_key_update;
vap->iv_key_update_end = null_key_update;
#ifdef ATH_SUPERG_COMP
vap->iv_comp_set = null_comp_set;
#endif
}
EXPORT_SYMBOL(ieee80211_crypto_vattach);
/*
* Teardown crypto support for a vap.
*/
void
ieee80211_crypto_vdetach(struct ieee80211vap *vap)
{
ieee80211_crypto_delglobalkeys(vap);
}
EXPORT_SYMBOL(ieee80211_crypto_vdetach);
/*
* Register a crypto cipher module.
*/
void
ieee80211_crypto_register(const struct ieee80211_cipher *cip)
{
if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
printk(KERN_ERR "%s: cipher %s has an invalid cipher index %u\n",
__func__, cip->ic_name, cip->ic_cipher);
return;
}
if ((ciphers[cip->ic_cipher] != NULL) && (ciphers[cip->ic_cipher] != cip)) {
printk(KERN_ERR "%s: cipher %s registered with a different template\n",
__func__, cip->ic_name);
return;
}
ciphers[cip->ic_cipher] = cip;
}
EXPORT_SYMBOL(ieee80211_crypto_register);
/*
* Unregister a crypto cipher module.
*/
void
ieee80211_crypto_unregister(const struct ieee80211_cipher *cip)
{
if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
printk(KERN_ERR "%s: cipher %s has an invalid cipher index %u\n",
__func__, cip->ic_name, cip->ic_cipher);
return;
}
if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) {
printk(KERN_ERR "%s: cipher %s registered with a different template\n",
__func__, cip->ic_name);
return;
}
/* NB: don't complain about not being registered */
/* XXX: disallow if referenced */
ciphers[cip->ic_cipher] = NULL;
}
EXPORT_SYMBOL(ieee80211_crypto_unregister);
/* XXX: well-known names! */
static const char *cipher_modnames[] = {
"wlan_wep", /* IEEE80211_CIPHER_WEP */
"wlan_tkip", /* IEEE80211_CIPHER_TKIP */
"wlan_aes_ocb", /* IEEE80211_CIPHER_AES_OCB */
"wlan_ccmp", /* IEEE80211_CIPHER_AES_CCM */
"wlan_ckip", /* IEEE80211_CIPHER_CKIP */
};
int
ieee80211_crypto_available(struct ieee80211vap *vap, u_int cipher)
{
unsigned int status = 0;
if (cipher < IEEE80211_CIPHER_MAX) {
if (ciphers[cipher] == NULL) {
/*
* Auto-load cipher module if we have a well-known name
* for it. It might be better to use string names rather
* than numbers and craft a module name based on the cipher
* name; e.g. wlan_cipher_<cipher-name>.
*/
if (cipher < ARRAY_SIZE(cipher_modnames)) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
"%s: unregistered cipher %u, load module %s\n",
__func__, cipher, cipher_modnames[cipher]);
ieee80211_load_module(cipher_modnames[cipher]);
/*
* If cipher module loaded it should immediately
* call ieee80211_crypto_register which will fill
* in the entry in the ciphers array.
*/
if (ciphers[cipher] == NULL) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
"%s: unable to load cipher %u, module %s\n",
__func__, cipher,
cipher < ARRAY_SIZE(cipher_modnames) ?
cipher_modnames[cipher] : "<unknown>");
vap->iv_stats.is_crypto_nocipher++;
} else
status = 1;
}
} else
status = 1;
}
return status;
}
EXPORT_SYMBOL(ieee80211_crypto_available);
/*
* Establish a relationship between the specified key and cipher
* and, if necessary, allocate a hardware index from the driver.
* Note that when a fixed key index is required it must be specified
* and we blindly assign it w/o consulting the driver (XXX).
*
* This must be the first call applied to a key; all the other key
* routines assume wk_cipher is setup.
*
* Locking must be handled by the caller using:
* ieee80211_key_update_begin(vap);
* ieee80211_key_update_end(vap);
*/
int
ieee80211_crypto_newkey(struct ieee80211vap *vap,
int cipher, int flags, struct ieee80211_key *key)
{
const struct ieee80211_cipher *cip;
void *keyctx;
int oflags;
/*
* Validate cipher and set reference to cipher routines.
*/
if (cipher >= IEEE80211_CIPHER_MAX) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
"%s: invalid cipher %u\n", __func__, cipher);
vap->iv_stats.is_crypto_badcipher++;
return 0;
}
cip = ciphers[cipher];
if (cip == NULL)
return 0;
oflags = key->wk_flags;
flags &= IEEE80211_KEY_COMMON;
/*
* If the hardware does not support the cipher then
* fallback to a host-based implementation.
*/
if (!(vap->iv_caps & (1 << cipher))) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
"%s: no h/w support for cipher %s, falling back to s/w\n",
__func__, cip->ic_name);
flags |= IEEE80211_KEY_SWCRYPT;
}
/*
* Hardware TKIP with software MIC is an important
* combination; we handle it by flagging each key,
* the cipher modules honor it.
*/
if (cipher == IEEE80211_CIPHER_TKIP) {
if (!(vap->iv_caps & IEEE80211_C_TKIPMIC)) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
"%s: no h/w support for TKIP MIC, falling back to s/w\n",
__func__);
flags |= IEEE80211_KEY_SWMIC;
} else if (!((vap->iv_caps & IEEE80211_C_WME_TKIPMIC)) &&
(vap->iv_flags & IEEE80211_F_WME)) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
"%s: no h/w support for TKIP MIC when WMM is turned on,"
" falling back to s/w\n",
__func__);
flags |= IEEE80211_KEY_SWMIC;
}
}
/*
* Bind cipher to key instance. Note we do this
* after checking the device capabilities so the
* cipher module can optimize space usage based on
* whether or not it needs to do the cipher work.
*/
if ((key->wk_cipher != cip) || (key->wk_flags != flags)) {
again:
/*
* Fill in the flags so cipher modules can see s/w
* crypto requirements and potentially allocate
* different state and/or attach different method
* pointers.
*
* XXX: This is not right when s/w crypto fallback
* fails and we try to restore previous state.
*/
key->wk_flags = flags;
keyctx = cip->ic_attach(vap, key);
if (keyctx == NULL) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
"%s: unable to attach cipher %s\n",
__func__, cip->ic_name);
key->wk_flags = oflags; /* restore old flags */
vap->iv_stats.is_crypto_attachfail++;
return 0;
}
cipher_detach(key);
key->wk_cipher = cip; /* XXX: refcnt? */
key->wk_private = keyctx;
}
/*
* Commit to requested usage so driver can see the flags.
*/
key->wk_flags = flags;
/*
* Ask the driver for a key index if we don't have one.
* Note that entries in the global key table always have
* an index; this means it's safe to call this routine
* for these entries just to setup the reference to the
* cipher template. Note also that when using software
* crypto we also call the driver to give us a key index.
*/
if (key->wk_keyix == IEEE80211_KEYIX_NONE) {
key->wk_keyix = dev_key_alloc(vap, key);
if (key->wk_keyix == IEEE80211_KEYIX_NONE) {
/*
* Driver has no room; fallback to doing crypto
* in the host. We change the flags and start the
* procedure over. If we get back here then there's
* no hope and we bail. Note that this can leave
* the key in a inconsistent state if the caller
* continues to use it.
*/
if ((key->wk_flags & IEEE80211_KEY_SWCRYPT) == 0) {
vap->iv_stats.is_crypto_swfallback++;
IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
"%s: no h/w resources for cipher %s, "
"falling back to s/w\n",
__func__, cip->ic_name);
oflags = key->wk_flags;
flags |= IEEE80211_KEY_SWCRYPT;
if (cipher == IEEE80211_CIPHER_TKIP)
flags |= IEEE80211_KEY_SWMIC;
goto again;
}
vap->iv_stats.is_crypto_keyfail++;
IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
"%s: unable to setup cipher %s\n",
__func__, cip->ic_name);
return 0;
}
}
return 1;
}
EXPORT_SYMBOL(ieee80211_crypto_newkey);
/*
* Remove the key (no locking, for internal use).
*/
static int
ieee80211_crypto_delkey_locked(struct ieee80211vap *vap, struct ieee80211_key *key,
struct ieee80211_node *ni)
{
ieee80211_keyix_t keyix;
KASSERT(key->wk_cipher != NULL, ("No cipher!"));
IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
"%s: %s keyix %u flags 0x%x tsc %llu len %u\n", __func__,
key->wk_cipher->ic_name, key->wk_keyix, key->wk_flags,
(unsigned long long)key->wk_keytsc, key->wk_keylen);
keyix = key->wk_keyix;
if (keyix != IEEE80211_KEYIX_NONE) {
/* Remove hardware entry. */
/* XXX: key cache */
if (!dev_key_delete(vap, key, ni)) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
"%s: driver did not delete key index %u\n",
__func__, keyix);
vap->iv_stats.is_crypto_delkey++;
/* XXX: recovery? */
}
}
cipher_detach(key);
memset(key, 0, sizeof(*key));
ieee80211_crypto_resetkey(vap, key, IEEE80211_KEYIX_NONE);
return 1;
}
/*
* Remove the specified key.
*/
int
ieee80211_crypto_delkey(struct ieee80211vap *vap, struct ieee80211_key *key,
struct ieee80211_node *ni)
{
int status;
#ifdef ATH_SUPERG_COMP
/* If valid node entry is present cleanup the compression state */
if (ni)
dev_comp_set(vap, ni, 0);
#endif
ieee80211_key_update_begin(vap);
status = ieee80211_crypto_delkey_locked(vap, key, ni);
ieee80211_key_update_end(vap);
return status;
}
EXPORT_SYMBOL(ieee80211_crypto_delkey);
/*
* Clear the global key table.
*/
void
ieee80211_crypto_delglobalkeys(struct ieee80211vap *vap)
{
int i;
ieee80211_key_update_begin(vap);
for (i = 0; i < IEEE80211_WEP_NKID; i++)
(void) ieee80211_crypto_delkey_locked(vap, &vap->iv_nw_keys[i], NULL);
ieee80211_key_update_end(vap);
}
EXPORT_SYMBOL(ieee80211_crypto_delglobalkeys);
/*
* Set the contents of the specified key.
*
* Locking must be handled by the caller using:
* ieee80211_key_update_begin(vap);
* ieee80211_key_update_end(vap);
*/
int
ieee80211_crypto_setkey(struct ieee80211vap *vap, struct ieee80211_key *key,
const u_int8_t macaddr[IEEE80211_ADDR_LEN],
struct ieee80211_node *ni)
{
const struct ieee80211_cipher *cip = key->wk_cipher;
int ret;
KASSERT(cip != NULL, ("No cipher!"));
IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
"%s: %s keyix %u flags 0x%x mac " MAC_FMT " tsc %llu len %u\n", __func__,
cip->ic_name, key->wk_keyix, key->wk_flags,
MAC_ADDR(macaddr), (unsigned long long)key->wk_keytsc,
key->wk_keylen);
/*
* Give cipher a chance to validate key contents.
* XXX: Should happen before modifying state.
*/
if (!cip->ic_setkey(key)) {
IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
"%s: cipher %s rejected key index %u len %u flags 0x%x\n",
__func__, cip->ic_name, key->wk_keyix,
key->wk_keylen, key->wk_flags);
vap->iv_stats.is_crypto_setkey_cipher++;
return 0;
}
if (key->wk_keyix == IEEE80211_KEYIX_NONE) {
/* NB: Nothing allocated, should not happen */
IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
"%s: no key index; should not happen!\n", __func__);
vap->iv_stats.is_crypto_setkey_nokey++;
return 0;
}
ret = dev_key_set(vap, key, macaddr);
#ifdef ATH_SUPERG_COMP
if (ret && ni) {
/* Enable decompression only on receive key entries */
if (key->wk_flags & IEEE80211_KEY_RECV)
dev_comp_set(vap, ni, 1);
}
#endif
return ret;
}
EXPORT_SYMBOL(ieee80211_crypto_setkey);
/*
* Add privacy headers appropriate for the specified key.
*/
struct ieee80211_key *
ieee80211_crypto_encap(struct ieee80211_node *ni, struct sk_buff *skb)
{
struct ieee80211vap *vap = ni->ni_vap;
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 = (struct ieee80211_frame *)skb->data;
if (IEEE80211_IS_MULTICAST(wh->i_addr1) ||
ni->ni_ucastkey.wk_cipher == &ieee80211_cipher_none) {
if (vap->iv_def_txkey == IEEE80211_KEYIX_NONE) {
IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO,
wh->i_addr1,
"no default transmit key (%s) deftxkey %u",
__func__, vap->iv_def_txkey);
vap->iv_stats.is_tx_nodefkey++;
return NULL;
}
keyid = vap->iv_def_txkey;
k = &vap->iv_nw_keys[vap->iv_def_txkey];
} else {
keyid = 0;
k = &ni->ni_ucastkey;
}
cip = k->wk_cipher;
if (skb_headroom(skb) < cip->ic_header) {
/*
* Should not happen; ieee80211_skbhdr_adjust should
* have allocated enough space for all headers.
*/
IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr1,
"%s: malformed packet for cipher %s; headroom %u",
__func__, cip->ic_name, skb_headroom(skb));
vap->iv_stats.is_tx_noheadroom++;
return NULL;
}
return (cip->ic_encap(k, skb, keyid << 6) ? k : NULL);
}
EXPORT_SYMBOL(ieee80211_crypto_encap);
/*
* Validate and strip privacy headers (and trailer) for a
* received frame that has the Protected Frame bit set.
*/
struct ieee80211_key *
ieee80211_crypto_decap(struct ieee80211_node *ni, struct sk_buff *skb, 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 ieee80211vap *vap = ni->ni_vap;
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 (skb->len < IEEE80211_WEP_MINLEN) {
IEEE80211_NOTE(vap, IEEE80211_MSG_ANY, ni,
"%s: WEP data frame too short, len %u",
__func__, skb->len);
vap->iv_stats.is_rx_tooshort++; /* XXX: 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 = (struct ieee80211_frame *)skb->data;
ivp = skb->data + hdrlen;
keyid = ivp[IEEE80211_WEP_IVLEN];
if (IEEE80211_IS_MULTICAST(wh->i_addr1) ||
ni->ni_ucastkey.wk_cipher == &ieee80211_cipher_none)
k = &vap->iv_nw_keys[keyid >> 6];
else
k = &ni->ni_ucastkey;
cip = k->wk_cipher;
return (cip->ic_decap(k, skb, hdrlen) ? k : NULL);
#undef IEEE80211_WEP_MINLEN
#undef IEEE80211_WEP_HDRLEN
}
EXPORT_SYMBOL(ieee80211_crypto_decap);
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