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freebsd-dev/sys/net80211/ieee80211_crypto.c
Sam Leffler c1225b52f6 Split crypto tx+rx key indices and add a key index -> node mapping table: 
Crypto changes:
o change driver/net80211 key_alloc api to return tx+rx key indices; a
  driver can leave the rx key index set to IEEE80211_KEYIX_NONE or set
  it to be the same as the tx key index (the former disables use of
  the key index in building the keyix->node mapping table and is the
  default setup for naive drivers by null_key_alloc)
o add cs_max_keyid to crypto state to specify the max h/w key index a
  driver will return; this is used to allocate the key index mapping
  table and to bounds check table loookups
o while here introduce ieee80211_keyix (finally) for the type of a h/w
  key index
o change crypto notifiers for rx failures to pass the rx key index up
  as appropriate (michael failure, replay, etc.)

Node table changes:
o optionally allocate a h/w key index to node mapping table for the
  station table using the max key index setting supplied by drivers
  (note the scan table does not get a map)
o defer node table allocation to lateattach so the driver has a chance
  to set the max key id to size the key index map
o while here also defer the aid bitmap allocation
o add new ieee80211_find_rxnode_withkey api to find a sta/node entry
  on frame receive with an optional h/w key index to use in checking
  mapping table; also updates the map if it does a hash lookup and the
  found node has a rx key index set in the unicast key; note this work
  is separated from the old ieee80211_find_rxnode call so drivers do
  not need to be aware of the new mechanism
o move some node table manipulation under the node table lock to close
  a race on node delete
o add ieee80211_node_delucastkey to do the dirty work of deleting
  unicast key state for a node (deletes any key and handles key map
  references)

Ath driver:
o nuke private sc_keyixmap mechansim in favor of net80211 support
o update key alloc api

These changes close several race conditions for the ath driver operating
in ap mode.  Other drivers should see no change.  Station mode operation
for ath no longer uses the key index map but performance tests show no
noticeable change and this will be fixed when the scan table is eliminated
with the new scanning support.

Tested by:	Michal Mertl, avatar, others
Reviewed by:	avatar, others
MFC after:	2 weeks
2005-08-08 18:46:36 +00:00

602 lines
17 KiB
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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* IEEE 802.11 generic crypto support.
*/
#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_media.h>
#include <net/ethernet.h> /* XXX ETHER_HDR_LEN */
#include <net80211/ieee80211_var.h>
/*
* Table of registered cipher modules.
*/
static const struct ieee80211_cipher *ciphers[IEEE80211_CIPHER_MAX];
static int _ieee80211_crypto_delkey(struct ieee80211com *,
struct ieee80211_key *);
/*
* Default "null" key management routines.
*/
static int
null_key_alloc(struct ieee80211com *ic, const struct ieee80211_key *k,
ieee80211_keyix *keyix, ieee80211_keyix *rxkeyix)
{
if (!(&ic->ic_nw_keys[0] <= k &&
k < &ic->ic_nw_keys[IEEE80211_WEP_NKID])) {
/*
* Not in the global key table, the driver should handle this
* by allocating a slot in the h/w key table/cache. In
* lieu of that return key slot 0 for any unicast key
* request. We disallow the request if this is a group key.
* This default policy does the right thing for legacy hardware
* with a 4 key table. It also handles devices that pass
* packets through untouched when marked with the WEP bit
* and key index 0.
*/
if (k->wk_flags & IEEE80211_KEY_GROUP)
return 0;
*keyix = 0; /* NB: use key index 0 for ucast key */
} else {
*keyix = k - ic->ic_nw_keys;
}
*rxkeyix = IEEE80211_KEYIX_NONE; /* XXX maybe *keyix? */
return 1;
}
static int
null_key_delete(struct ieee80211com *ic, const struct ieee80211_key *k)
{
return 1;
}
static int
null_key_set(struct ieee80211com *ic, const struct ieee80211_key *k,
const u_int8_t mac[IEEE80211_ADDR_LEN])
{
return 1;
}
static void null_key_update(struct ieee80211com *ic) {}
/*
* 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 ieee80211com *ic, struct ieee80211_key *key)
{
return key->wk_cipher->ic_attach(ic, key);
}
/*
* Wrappers for driver key management methods.
*/
static __inline int
dev_key_alloc(struct ieee80211com *ic,
const struct ieee80211_key *key,
ieee80211_keyix *keyix, ieee80211_keyix *rxkeyix)
{
return ic->ic_crypto.cs_key_alloc(ic, key, keyix, rxkeyix);
}
static __inline int
dev_key_delete(struct ieee80211com *ic,
const struct ieee80211_key *key)
{
return ic->ic_crypto.cs_key_delete(ic, key);
}
static __inline int
dev_key_set(struct ieee80211com *ic, const struct ieee80211_key *key,
const u_int8_t mac[IEEE80211_ADDR_LEN])
{
return ic->ic_crypto.cs_key_set(ic, key, mac);
}
/*
* Setup crypto support.
*/
void
ieee80211_crypto_attach(struct ieee80211com *ic)
{
struct ieee80211_crypto_state *cs = &ic->ic_crypto;
int i;
/* NB: we assume everything is pre-zero'd */
cs->cs_def_txkey = IEEE80211_KEYIX_NONE;
cs->cs_max_keyix = IEEE80211_WEP_NKID;
ciphers[IEEE80211_CIPHER_NONE] = &ieee80211_cipher_none;
for (i = 0; i < IEEE80211_WEP_NKID; i++)
ieee80211_crypto_resetkey(ic, &cs->cs_nw_keys[i],
IEEE80211_KEYIX_NONE);
/*
* Initialize the driver key support routines to noop entries.
* This is useful especially for the cipher test modules.
*/
cs->cs_key_alloc = null_key_alloc;
cs->cs_key_set = null_key_set;
cs->cs_key_delete = null_key_delete;
cs->cs_key_update_begin = null_key_update;
cs->cs_key_update_end = null_key_update;
}
/*
* Teardown crypto support.
*/
void
ieee80211_crypto_detach(struct ieee80211com *ic)
{
ieee80211_crypto_delglobalkeys(ic);
}
/*
* Register a crypto cipher module.
*/
void
ieee80211_crypto_register(const struct ieee80211_cipher *cip)
{
if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
printf("%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) {
printf("%s: cipher %s registered with a different template\n",
__func__, cip->ic_name);
return;
}
ciphers[cip->ic_cipher] = cip;
}
/*
* Unregister a crypto cipher module.
*/
void
ieee80211_crypto_unregister(const struct ieee80211_cipher *cip)
{
if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
printf("%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) {
printf("%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 references */
ciphers[cip->ic_cipher] = NULL;
}
int
ieee80211_crypto_available(u_int cipher)
{
return cipher < IEEE80211_CIPHER_MAX && ciphers[cipher] != NULL;
}
/* 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 */
};
/*
* 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(ic);
* ieee80211_key_update_end(ic);
*/
int
ieee80211_crypto_newkey(struct ieee80211com *ic,
int cipher, int flags, struct ieee80211_key *key)
{
#define N(a) (sizeof(a) / sizeof(a[0]))
const struct ieee80211_cipher *cip;
ieee80211_keyix keyix, rxkeyix;
void *keyctx;
int oflags;
/*
* Validate cipher and set reference to cipher routines.
*/
if (cipher >= IEEE80211_CIPHER_MAX) {
IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
"%s: invalid cipher %u\n", __func__, cipher);
ic->ic_stats.is_crypto_badcipher++;
return 0;
}
cip = ciphers[cipher];
if (cip == 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 < N(cipher_modnames)) {
IEEE80211_DPRINTF(ic, 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.
*/
cip = ciphers[cipher];
}
if (cip == NULL) {
IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
"%s: unable to load cipher %u, module %s\n",
__func__, cipher,
cipher < N(cipher_modnames) ?
cipher_modnames[cipher] : "<unknown>");
ic->ic_stats.is_crypto_nocipher++;
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 ((ic->ic_caps & (1<<cipher)) == 0) {
IEEE80211_DPRINTF(ic, 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 &&
(ic->ic_caps & IEEE80211_C_TKIPMIC) == 0) {
IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
"%s: no h/w support for TKIP MIC, 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:
/*
* Fillin 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(ic, key);
if (keyctx == NULL) {
IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
"%s: unable to attach cipher %s\n",
__func__, cip->ic_name);
key->wk_flags = oflags; /* restore old flags */
ic->ic_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) {
if (!dev_key_alloc(ic, key, &keyix, &rxkeyix)) {
/*
* 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) {
ic->ic_stats.is_crypto_swfallback++;
IEEE80211_DPRINTF(ic, 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;
}
ic->ic_stats.is_crypto_keyfail++;
IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
"%s: unable to setup cipher %s\n",
__func__, cip->ic_name);
return 0;
}
key->wk_keyix = keyix;
key->wk_rxkeyix = rxkeyix;
}
return 1;
#undef N
}
/*
* Remove the key (no locking, for internal use).
*/
static int
_ieee80211_crypto_delkey(struct ieee80211com *ic, struct ieee80211_key *key)
{
ieee80211_keyix keyix;
KASSERT(key->wk_cipher != NULL, ("No cipher!"));
IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
"%s: %s keyix %u flags 0x%x rsc %ju tsc %ju len %u\n",
__func__, key->wk_cipher->ic_name,
key->wk_keyix, key->wk_flags,
key->wk_keyrsc, 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(ic, key)) {
IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
"%s: driver did not delete key index %u\n",
__func__, keyix);
ic->ic_stats.is_crypto_delkey++;
/* XXX recovery? */
}
}
cipher_detach(key);
memset(key, 0, sizeof(*key));
ieee80211_crypto_resetkey(ic, key, IEEE80211_KEYIX_NONE);
return 1;
}
/*
* Remove the specified key.
*/
int
ieee80211_crypto_delkey(struct ieee80211com *ic, struct ieee80211_key *key)
{
int status;
ieee80211_key_update_begin(ic);
status = _ieee80211_crypto_delkey(ic, key);
ieee80211_key_update_end(ic);
return status;
}
/*
* Clear the global key table.
*/
void
ieee80211_crypto_delglobalkeys(struct ieee80211com *ic)
{
int i;
ieee80211_key_update_begin(ic);
for (i = 0; i < IEEE80211_WEP_NKID; i++)
(void) _ieee80211_crypto_delkey(ic, &ic->ic_nw_keys[i]);
ieee80211_key_update_end(ic);
}
/*
* Set the contents of the specified key.
*
* Locking must be handled by the caller using:
* ieee80211_key_update_begin(ic);
* ieee80211_key_update_end(ic);
*/
int
ieee80211_crypto_setkey(struct ieee80211com *ic, struct ieee80211_key *key,
const u_int8_t macaddr[IEEE80211_ADDR_LEN])
{
const struct ieee80211_cipher *cip = key->wk_cipher;
KASSERT(cip != NULL, ("No cipher!"));
IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
"%s: %s keyix %u flags 0x%x mac %s rsc %ju tsc %ju len %u\n",
__func__, cip->ic_name, key->wk_keyix,
key->wk_flags, ether_sprintf(macaddr),
key->wk_keyrsc, 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(ic, 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);
ic->ic_stats.is_crypto_setkey_cipher++;
return 0;
}
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) ||
ni->ni_ucastkey.wk_cipher == &ieee80211_cipher_none) {
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) ||
ni->ni_ucastkey.wk_cipher == &ieee80211_cipher_none)
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
}
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