The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/net80211/ieee80211_crypto.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
    3  *
    4  * Copyright (c) 2001 Atsushi Onoe
    5  * Copyright (c) 2002-2008 Sam Leffler, Errno Consulting
    6  * All rights reserved.
    7  *
    8  * Redistribution and use in source and binary forms, with or without
    9  * modification, are permitted provided that the following conditions
   10  * are met:
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   27  */
   28 
   29 #include <sys/cdefs.h>
   30 __FBSDID("$FreeBSD: releng/12.0/sys/net80211/ieee80211_crypto.c 326272 2017-11-27 15:23:17Z pfg $");
   31 
   32 /*
   33  * IEEE 802.11 generic crypto support.
   34  */
   35 #include "opt_wlan.h"
   36 
   37 #include <sys/param.h>
   38 #include <sys/kernel.h>
   39 #include <sys/malloc.h>
   40 #include <sys/mbuf.h>   
   41 
   42 #include <sys/socket.h>
   43 
   44 #include <net/if.h>
   45 #include <net/if_media.h>
   46 #include <net/ethernet.h>               /* XXX ETHER_HDR_LEN */
   47 
   48 #include <net80211/ieee80211_var.h>
   49 
   50 MALLOC_DEFINE(M_80211_CRYPTO, "80211crypto", "802.11 crypto state");
   51 
   52 static  int _ieee80211_crypto_delkey(struct ieee80211vap *,
   53                 struct ieee80211_key *);
   54 
   55 /*
   56  * Table of registered cipher modules.
   57  */
   58 static  const struct ieee80211_cipher *ciphers[IEEE80211_CIPHER_MAX];
   59 
   60 /*
   61  * Default "null" key management routines.
   62  */
   63 static int
   64 null_key_alloc(struct ieee80211vap *vap, struct ieee80211_key *k,
   65         ieee80211_keyix *keyix, ieee80211_keyix *rxkeyix)
   66 {
   67         if (!(&vap->iv_nw_keys[0] <= k &&
   68              k < &vap->iv_nw_keys[IEEE80211_WEP_NKID])) {
   69                 /*
   70                  * Not in the global key table, the driver should handle this
   71                  * by allocating a slot in the h/w key table/cache.  In
   72                  * lieu of that return key slot 0 for any unicast key
   73                  * request.  We disallow the request if this is a group key.
   74                  * This default policy does the right thing for legacy hardware
   75                  * with a 4 key table.  It also handles devices that pass
   76                  * packets through untouched when marked with the WEP bit
   77                  * and key index 0.
   78                  */
   79                 if (k->wk_flags & IEEE80211_KEY_GROUP)
   80                         return 0;
   81                 *keyix = 0;     /* NB: use key index 0 for ucast key */
   82         } else {
   83                 *keyix = ieee80211_crypto_get_key_wepidx(vap, k);
   84         }
   85         *rxkeyix = IEEE80211_KEYIX_NONE;        /* XXX maybe *keyix? */
   86         return 1;
   87 }
   88 static int
   89 null_key_delete(struct ieee80211vap *vap, const struct ieee80211_key *k)
   90 {
   91         return 1;
   92 }
   93 static  int
   94 null_key_set(struct ieee80211vap *vap, const struct ieee80211_key *k)
   95 {
   96         return 1;
   97 }
   98 static void null_key_update(struct ieee80211vap *vap) {}
   99 
  100 /*
  101  * Write-arounds for common operations.
  102  */
  103 static __inline void
  104 cipher_detach(struct ieee80211_key *key)
  105 {
  106         key->wk_cipher->ic_detach(key);
  107 }
  108 
  109 static __inline void *
  110 cipher_attach(struct ieee80211vap *vap, struct ieee80211_key *key)
  111 {
  112         return key->wk_cipher->ic_attach(vap, key);
  113 }
  114 
  115 /* 
  116  * Wrappers for driver key management methods.
  117  */
  118 static __inline int
  119 dev_key_alloc(struct ieee80211vap *vap,
  120         struct ieee80211_key *key,
  121         ieee80211_keyix *keyix, ieee80211_keyix *rxkeyix)
  122 {
  123         return vap->iv_key_alloc(vap, key, keyix, rxkeyix);
  124 }
  125 
  126 static __inline int
  127 dev_key_delete(struct ieee80211vap *vap,
  128         const struct ieee80211_key *key)
  129 {
  130         return vap->iv_key_delete(vap, key);
  131 }
  132 
  133 static __inline int
  134 dev_key_set(struct ieee80211vap *vap, const struct ieee80211_key *key)
  135 {
  136         return vap->iv_key_set(vap, key);
  137 }
  138 
  139 /*
  140  * Setup crypto support for a device/shared instance.
  141  */
  142 void
  143 ieee80211_crypto_attach(struct ieee80211com *ic)
  144 {
  145         /* NB: we assume everything is pre-zero'd */
  146         ciphers[IEEE80211_CIPHER_NONE] = &ieee80211_cipher_none;
  147 }
  148 
  149 /*
  150  * Teardown crypto support.
  151  */
  152 void
  153 ieee80211_crypto_detach(struct ieee80211com *ic)
  154 {
  155 }
  156 
  157 /*
  158  * Setup crypto support for a vap.
  159  */
  160 void
  161 ieee80211_crypto_vattach(struct ieee80211vap *vap)
  162 {
  163         int i;
  164 
  165         /* NB: we assume everything is pre-zero'd */
  166         vap->iv_max_keyix = IEEE80211_WEP_NKID;
  167         vap->iv_def_txkey = IEEE80211_KEYIX_NONE;
  168         for (i = 0; i < IEEE80211_WEP_NKID; i++)
  169                 ieee80211_crypto_resetkey(vap, &vap->iv_nw_keys[i],
  170                         IEEE80211_KEYIX_NONE);
  171         /*
  172          * Initialize the driver key support routines to noop entries.
  173          * This is useful especially for the cipher test modules.
  174          */
  175         vap->iv_key_alloc = null_key_alloc;
  176         vap->iv_key_set = null_key_set;
  177         vap->iv_key_delete = null_key_delete;
  178         vap->iv_key_update_begin = null_key_update;
  179         vap->iv_key_update_end = null_key_update;
  180 }
  181 
  182 /*
  183  * Teardown crypto support for a vap.
  184  */
  185 void
  186 ieee80211_crypto_vdetach(struct ieee80211vap *vap)
  187 {
  188         ieee80211_crypto_delglobalkeys(vap);
  189 }
  190 
  191 /*
  192  * Register a crypto cipher module.
  193  */
  194 void
  195 ieee80211_crypto_register(const struct ieee80211_cipher *cip)
  196 {
  197         if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
  198                 printf("%s: cipher %s has an invalid cipher index %u\n",
  199                         __func__, cip->ic_name, cip->ic_cipher);
  200                 return;
  201         }
  202         if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) {
  203                 printf("%s: cipher %s registered with a different template\n",
  204                         __func__, cip->ic_name);
  205                 return;
  206         }
  207         ciphers[cip->ic_cipher] = cip;
  208 }
  209 
  210 /*
  211  * Unregister a crypto cipher module.
  212  */
  213 void
  214 ieee80211_crypto_unregister(const struct ieee80211_cipher *cip)
  215 {
  216         if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) {
  217                 printf("%s: cipher %s has an invalid cipher index %u\n",
  218                         __func__, cip->ic_name, cip->ic_cipher);
  219                 return;
  220         }
  221         if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) {
  222                 printf("%s: cipher %s registered with a different template\n",
  223                         __func__, cip->ic_name);
  224                 return;
  225         }
  226         /* NB: don't complain about not being registered */
  227         /* XXX disallow if references */
  228         ciphers[cip->ic_cipher] = NULL;
  229 }
  230 
  231 int
  232 ieee80211_crypto_available(u_int cipher)
  233 {
  234         return cipher < IEEE80211_CIPHER_MAX && ciphers[cipher] != NULL;
  235 }
  236 
  237 /* XXX well-known names! */
  238 static const char *cipher_modnames[IEEE80211_CIPHER_MAX] = {
  239         [IEEE80211_CIPHER_WEP]     = "wlan_wep",
  240         [IEEE80211_CIPHER_TKIP]    = "wlan_tkip",
  241         [IEEE80211_CIPHER_AES_OCB] = "wlan_aes_ocb",
  242         [IEEE80211_CIPHER_AES_CCM] = "wlan_ccmp",
  243         [IEEE80211_CIPHER_TKIPMIC] = "#4",      /* NB: reserved */
  244         [IEEE80211_CIPHER_CKIP]    = "wlan_ckip",
  245         [IEEE80211_CIPHER_NONE]    = "wlan_none",
  246 };
  247 
  248 /* NB: there must be no overlap between user-supplied and device-owned flags */
  249 CTASSERT((IEEE80211_KEY_COMMON & IEEE80211_KEY_DEVICE) == 0);
  250 
  251 /*
  252  * Establish a relationship between the specified key and cipher
  253  * and, if necessary, allocate a hardware index from the driver.
  254  * Note that when a fixed key index is required it must be specified.
  255  *
  256  * This must be the first call applied to a key; all the other key
  257  * routines assume wk_cipher is setup.
  258  *
  259  * Locking must be handled by the caller using:
  260  *      ieee80211_key_update_begin(vap);
  261  *      ieee80211_key_update_end(vap);
  262  */
  263 int
  264 ieee80211_crypto_newkey(struct ieee80211vap *vap,
  265         int cipher, int flags, struct ieee80211_key *key)
  266 {
  267         struct ieee80211com *ic = vap->iv_ic;
  268         const struct ieee80211_cipher *cip;
  269         ieee80211_keyix keyix, rxkeyix;
  270         void *keyctx;
  271         int oflags;
  272 
  273         IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
  274             "%s: cipher %u flags 0x%x keyix %u\n",
  275             __func__, cipher, flags, key->wk_keyix);
  276 
  277         /*
  278          * Validate cipher and set reference to cipher routines.
  279          */
  280         if (cipher >= IEEE80211_CIPHER_MAX) {
  281                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
  282                     "%s: invalid cipher %u\n", __func__, cipher);
  283                 vap->iv_stats.is_crypto_badcipher++;
  284                 return 0;
  285         }
  286         cip = ciphers[cipher];
  287         if (cip == NULL) {
  288                 /*
  289                  * Auto-load cipher module if we have a well-known name
  290                  * for it.  It might be better to use string names rather
  291                  * than numbers and craft a module name based on the cipher
  292                  * name; e.g. wlan_cipher_<cipher-name>.
  293                  */
  294                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
  295                     "%s: unregistered cipher %u, load module %s\n",
  296                     __func__, cipher, cipher_modnames[cipher]);
  297                 ieee80211_load_module(cipher_modnames[cipher]);
  298                 /*
  299                  * If cipher module loaded it should immediately
  300                  * call ieee80211_crypto_register which will fill
  301                  * in the entry in the ciphers array.
  302                  */
  303                 cip = ciphers[cipher];
  304                 if (cip == NULL) {
  305                         IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
  306                             "%s: unable to load cipher %u, module %s\n",
  307                             __func__, cipher, cipher_modnames[cipher]);
  308                         vap->iv_stats.is_crypto_nocipher++;
  309                         return 0;
  310                 }
  311         }
  312 
  313         oflags = key->wk_flags;
  314         flags &= IEEE80211_KEY_COMMON;
  315         /* NB: preserve device attributes */
  316         flags |= (oflags & IEEE80211_KEY_DEVICE);
  317         /*
  318          * If the hardware does not support the cipher then
  319          * fallback to a host-based implementation.
  320          */
  321         if ((ic->ic_cryptocaps & (1<<cipher)) == 0) {
  322                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
  323                     "%s: no h/w support for cipher %s, falling back to s/w\n",
  324                     __func__, cip->ic_name);
  325                 flags |= IEEE80211_KEY_SWCRYPT;
  326         }
  327         /*
  328          * Hardware TKIP with software MIC is an important
  329          * combination; we handle it by flagging each key,
  330          * the cipher modules honor it.
  331          */
  332         if (cipher == IEEE80211_CIPHER_TKIP &&
  333             (ic->ic_cryptocaps & IEEE80211_CRYPTO_TKIPMIC) == 0) {
  334                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
  335                     "%s: no h/w support for TKIP MIC, falling back to s/w\n",
  336                     __func__);
  337                 flags |= IEEE80211_KEY_SWMIC;
  338         }
  339 
  340         /*
  341          * Bind cipher to key instance.  Note we do this
  342          * after checking the device capabilities so the
  343          * cipher module can optimize space usage based on
  344          * whether or not it needs to do the cipher work.
  345          */
  346         if (key->wk_cipher != cip || key->wk_flags != flags) {
  347                 /*
  348                  * Fillin the flags so cipher modules can see s/w
  349                  * crypto requirements and potentially allocate
  350                  * different state and/or attach different method
  351                  * pointers.
  352                  */
  353                 key->wk_flags = flags;
  354                 keyctx = cip->ic_attach(vap, key);
  355                 if (keyctx == NULL) {
  356                         IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
  357                                 "%s: unable to attach cipher %s\n",
  358                                 __func__, cip->ic_name);
  359                         key->wk_flags = oflags; /* restore old flags */
  360                         vap->iv_stats.is_crypto_attachfail++;
  361                         return 0;
  362                 }
  363                 cipher_detach(key);
  364                 key->wk_cipher = cip;           /* XXX refcnt? */
  365                 key->wk_private = keyctx;
  366         }
  367 
  368         /*
  369          * Ask the driver for a key index if we don't have one.
  370          * Note that entries in the global key table always have
  371          * an index; this means it's safe to call this routine
  372          * for these entries just to setup the reference to the
  373          * cipher template.  Note also that when using software
  374          * crypto we also call the driver to give us a key index.
  375          */
  376         if ((key->wk_flags & IEEE80211_KEY_DEVKEY) == 0) {
  377                 if (!dev_key_alloc(vap, key, &keyix, &rxkeyix)) {
  378                         /*
  379                          * Unable to setup driver state.
  380                          */
  381                         vap->iv_stats.is_crypto_keyfail++;
  382                         IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
  383                             "%s: unable to setup cipher %s\n",
  384                             __func__, cip->ic_name);
  385                         return 0;
  386                 }
  387                 if (key->wk_flags != flags) {
  388                         /*
  389                          * Driver overrode flags we setup; typically because
  390                          * resources were unavailable to handle _this_ key.
  391                          * Re-attach the cipher context to allow cipher
  392                          * modules to handle differing requirements.
  393                          */
  394                         IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
  395                             "%s: driver override for cipher %s, flags "
  396                             "0x%x -> 0x%x\n", __func__, cip->ic_name,
  397                             oflags, key->wk_flags);
  398                         keyctx = cip->ic_attach(vap, key);
  399                         if (keyctx == NULL) {
  400                                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
  401                                     "%s: unable to attach cipher %s with "
  402                                     "flags 0x%x\n", __func__, cip->ic_name,
  403                                     key->wk_flags);
  404                                 key->wk_flags = oflags; /* restore old flags */
  405                                 vap->iv_stats.is_crypto_attachfail++;
  406                                 return 0;
  407                         }
  408                         cipher_detach(key);
  409                         key->wk_cipher = cip;           /* XXX refcnt? */
  410                         key->wk_private = keyctx;
  411                 }
  412                 key->wk_keyix = keyix;
  413                 key->wk_rxkeyix = rxkeyix;
  414                 key->wk_flags |= IEEE80211_KEY_DEVKEY;
  415         }
  416         return 1;
  417 }
  418 
  419 /*
  420  * Remove the key (no locking, for internal use).
  421  */
  422 static int
  423 _ieee80211_crypto_delkey(struct ieee80211vap *vap, struct ieee80211_key *key)
  424 {
  425         KASSERT(key->wk_cipher != NULL, ("No cipher!"));
  426 
  427         IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
  428             "%s: %s keyix %u flags 0x%x rsc %ju tsc %ju len %u\n",
  429             __func__, key->wk_cipher->ic_name,
  430             key->wk_keyix, key->wk_flags,
  431             key->wk_keyrsc[IEEE80211_NONQOS_TID], key->wk_keytsc,
  432             key->wk_keylen);
  433 
  434         if (key->wk_flags & IEEE80211_KEY_DEVKEY) {
  435                 /*
  436                  * Remove hardware entry.
  437                  */
  438                 /* XXX key cache */
  439                 if (!dev_key_delete(vap, key)) {
  440                         IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
  441                             "%s: driver did not delete key index %u\n",
  442                             __func__, key->wk_keyix);
  443                         vap->iv_stats.is_crypto_delkey++;
  444                         /* XXX recovery? */
  445                 }
  446         }
  447         cipher_detach(key);
  448         memset(key, 0, sizeof(*key));
  449         ieee80211_crypto_resetkey(vap, key, IEEE80211_KEYIX_NONE);
  450         return 1;
  451 }
  452 
  453 /*
  454  * Remove the specified key.
  455  */
  456 int
  457 ieee80211_crypto_delkey(struct ieee80211vap *vap, struct ieee80211_key *key)
  458 {
  459         int status;
  460 
  461         ieee80211_key_update_begin(vap);
  462         status = _ieee80211_crypto_delkey(vap, key);
  463         ieee80211_key_update_end(vap);
  464         return status;
  465 }
  466 
  467 /*
  468  * Clear the global key table.
  469  */
  470 void
  471 ieee80211_crypto_delglobalkeys(struct ieee80211vap *vap)
  472 {
  473         int i;
  474 
  475         ieee80211_key_update_begin(vap);
  476         for (i = 0; i < IEEE80211_WEP_NKID; i++)
  477                 (void) _ieee80211_crypto_delkey(vap, &vap->iv_nw_keys[i]);
  478         ieee80211_key_update_end(vap);
  479 }
  480 
  481 /*
  482  * Set the contents of the specified key.
  483  *
  484  * Locking must be handled by the caller using:
  485  *      ieee80211_key_update_begin(vap);
  486  *      ieee80211_key_update_end(vap);
  487  */
  488 int
  489 ieee80211_crypto_setkey(struct ieee80211vap *vap, struct ieee80211_key *key)
  490 {
  491         const struct ieee80211_cipher *cip = key->wk_cipher;
  492 
  493         KASSERT(cip != NULL, ("No cipher!"));
  494 
  495         IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
  496             "%s: %s keyix %u flags 0x%x mac %s rsc %ju tsc %ju len %u\n",
  497             __func__, cip->ic_name, key->wk_keyix,
  498             key->wk_flags, ether_sprintf(key->wk_macaddr),
  499             key->wk_keyrsc[IEEE80211_NONQOS_TID], key->wk_keytsc,
  500             key->wk_keylen);
  501 
  502         if ((key->wk_flags & IEEE80211_KEY_DEVKEY)  == 0) {
  503                 /* XXX nothing allocated, should not happen */
  504                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
  505                     "%s: no device key setup done; should not happen!\n",
  506                     __func__);
  507                 vap->iv_stats.is_crypto_setkey_nokey++;
  508                 return 0;
  509         }
  510         /*
  511          * Give cipher a chance to validate key contents.
  512          * XXX should happen before modifying state.
  513          */
  514         if (!cip->ic_setkey(key)) {
  515                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO,
  516                     "%s: cipher %s rejected key index %u len %u flags 0x%x\n",
  517                     __func__, cip->ic_name, key->wk_keyix,
  518                     key->wk_keylen, key->wk_flags);
  519                 vap->iv_stats.is_crypto_setkey_cipher++;
  520                 return 0;
  521         }
  522         return dev_key_set(vap, key);
  523 }
  524 
  525 /*
  526  * Return index if the key is a WEP key (0..3); -1 otherwise.
  527  *
  528  * This is different to "get_keyid" which defaults to returning
  529  * 0 for unicast keys; it assumes that it won't be used for WEP.
  530  */
  531 int
  532 ieee80211_crypto_get_key_wepidx(const struct ieee80211vap *vap,
  533     const struct ieee80211_key *k)
  534 {
  535 
  536         if (k >= &vap->iv_nw_keys[0] &&
  537             k <  &vap->iv_nw_keys[IEEE80211_WEP_NKID])
  538                 return (k - vap->iv_nw_keys);
  539         return (-1);
  540 }
  541 
  542 /*
  543  * Note: only supports a single unicast key (0).
  544  */
  545 uint8_t
  546 ieee80211_crypto_get_keyid(struct ieee80211vap *vap, struct ieee80211_key *k)
  547 {
  548         if (k >= &vap->iv_nw_keys[0] &&
  549             k <  &vap->iv_nw_keys[IEEE80211_WEP_NKID])
  550                 return (k - vap->iv_nw_keys);
  551         else
  552                 return (0);
  553 }
  554 
  555 struct ieee80211_key *
  556 ieee80211_crypto_get_txkey(struct ieee80211_node *ni, struct mbuf *m)
  557 {
  558         struct ieee80211vap *vap = ni->ni_vap;
  559         struct ieee80211_frame *wh;
  560 
  561         /*
  562          * Multicast traffic always uses the multicast key.
  563          * Otherwise if a unicast key is set we use that and
  564          * it is always key index 0.  When no unicast key is
  565          * set we fall back to the default transmit key.
  566          */
  567         wh = mtod(m, struct ieee80211_frame *);
  568         if (IEEE80211_IS_MULTICAST(wh->i_addr1) ||
  569             IEEE80211_KEY_UNDEFINED(&ni->ni_ucastkey)) {
  570                 if (vap->iv_def_txkey == IEEE80211_KEYIX_NONE) {
  571                         IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO,
  572                             wh->i_addr1,
  573                             "no default transmit key (%s) deftxkey %u",
  574                             __func__, vap->iv_def_txkey);
  575                         vap->iv_stats.is_tx_nodefkey++;
  576                         return NULL;
  577                 }
  578                 return &vap->iv_nw_keys[vap->iv_def_txkey];
  579         }
  580 
  581         return &ni->ni_ucastkey;
  582 }
  583 
  584 /*
  585  * Add privacy headers appropriate for the specified key.
  586  */
  587 struct ieee80211_key *
  588 ieee80211_crypto_encap(struct ieee80211_node *ni, struct mbuf *m)
  589 {
  590         struct ieee80211_key *k;
  591         const struct ieee80211_cipher *cip;
  592 
  593         if ((k = ieee80211_crypto_get_txkey(ni, m)) != NULL) {
  594                 cip = k->wk_cipher;
  595                 return (cip->ic_encap(k, m) ? k : NULL);
  596         }
  597 
  598         return NULL;
  599 }
  600 
  601 /*
  602  * Validate and strip privacy headers (and trailer) for a
  603  * received frame that has the WEP/Privacy bit set.
  604  */
  605 int
  606 ieee80211_crypto_decap(struct ieee80211_node *ni, struct mbuf *m, int hdrlen,
  607     struct ieee80211_key **key)
  608 {
  609 #define IEEE80211_WEP_HDRLEN    (IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN)
  610 #define IEEE80211_WEP_MINLEN \
  611         (sizeof(struct ieee80211_frame) + \
  612         IEEE80211_WEP_HDRLEN + IEEE80211_WEP_CRCLEN)
  613         struct ieee80211vap *vap = ni->ni_vap;
  614         struct ieee80211_key *k;
  615         struct ieee80211_frame *wh;
  616         const struct ieee80211_rx_stats *rxs;
  617         const struct ieee80211_cipher *cip;
  618         uint8_t keyid;
  619 
  620         /*
  621          * Check for hardware decryption and IV stripping.
  622          * If the IV is stripped then we definitely can't find a key.
  623          * Set the key to NULL but return true; upper layers
  624          * will need to handle a NULL key for a successful
  625          * decrypt.
  626          */
  627         rxs = ieee80211_get_rx_params_ptr(m);
  628         if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_DECRYPTED)) {
  629                 if (rxs->c_pktflags & IEEE80211_RX_F_IV_STRIP) {
  630                         /*
  631                          * Hardware decrypted, IV stripped.
  632                          * We can't find a key with a stripped IV.
  633                          * Return successful.
  634                          */
  635                         *key = NULL;
  636                         return (1);
  637                 }
  638         }
  639 
  640         /* NB: this minimum size data frame could be bigger */
  641         if (m->m_pkthdr.len < IEEE80211_WEP_MINLEN) {
  642                 IEEE80211_DPRINTF(vap, IEEE80211_MSG_ANY,
  643                         "%s: WEP data frame too short, len %u\n",
  644                         __func__, m->m_pkthdr.len);
  645                 vap->iv_stats.is_rx_tooshort++; /* XXX need unique stat? */
  646                 *key = NULL;
  647                 return (0);
  648         }
  649 
  650         /*
  651          * Locate the key. If unicast and there is no unicast
  652          * key then we fall back to the key id in the header.
  653          * This assumes unicast keys are only configured when
  654          * the key id in the header is meaningless (typically 0).
  655          */
  656         wh = mtod(m, struct ieee80211_frame *);
  657         m_copydata(m, hdrlen + IEEE80211_WEP_IVLEN, sizeof(keyid), &keyid);
  658         if (IEEE80211_IS_MULTICAST(wh->i_addr1) ||
  659             IEEE80211_KEY_UNDEFINED(&ni->ni_ucastkey))
  660                 k = &vap->iv_nw_keys[keyid >> 6];
  661         else
  662                 k = &ni->ni_ucastkey;
  663 
  664         /*
  665          * Insure crypto header is contiguous for all decap work.
  666          */
  667         cip = k->wk_cipher;
  668         if (m->m_len < hdrlen + cip->ic_header &&
  669             (m = m_pullup(m, hdrlen + cip->ic_header)) == NULL) {
  670                 IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2,
  671                     "unable to pullup %s header", cip->ic_name);
  672                 vap->iv_stats.is_rx_wepfail++;  /* XXX */
  673                 *key = NULL;
  674                 return (0);
  675         }
  676 
  677         /*
  678          * Attempt decryption.
  679          *
  680          * If we fail then don't return the key - return NULL
  681          * and an error.
  682          */
  683         if (cip->ic_decap(k, m, hdrlen)) {
  684                 /* success */
  685                 *key = k;
  686                 return (1);
  687         }
  688 
  689         /* Failure */
  690         *key = NULL;
  691         return (0);
  692 #undef IEEE80211_WEP_MINLEN
  693 #undef IEEE80211_WEP_HDRLEN
  694 }
  695 
  696 /*
  697  * Check and remove any MIC.
  698  */
  699 int
  700 ieee80211_crypto_demic(struct ieee80211vap *vap, struct ieee80211_key *k,
  701     struct mbuf *m, int force)
  702 {
  703         const struct ieee80211_cipher *cip;
  704         const struct ieee80211_rx_stats *rxs;
  705         struct ieee80211_frame *wh;
  706 
  707         rxs = ieee80211_get_rx_params_ptr(m);
  708         wh = mtod(m, struct ieee80211_frame *);
  709 
  710         /*
  711          * Handle demic / mic errors from hardware-decrypted offload devices.
  712          */
  713         if ((rxs != NULL) && (rxs->c_pktflags & IEEE80211_RX_F_DECRYPTED)) {
  714                 if (rxs->c_pktflags & IEEE80211_RX_F_FAIL_MIC) {
  715                         /*
  716                          * Hardware has said MIC failed.  We don't care about
  717                          * whether it was stripped or not.
  718                          *
  719                          * Eventually - teach the demic methods in crypto
  720                          * modules to handle a NULL key and not to dereference
  721                          * it.
  722                          */
  723                         ieee80211_notify_michael_failure(vap, wh, -1);
  724                         return (0);
  725                 }
  726 
  727                 if (rxs->c_pktflags & IEEE80211_RX_F_MMIC_STRIP) {
  728                         /*
  729                          * Hardware has decrypted and not indicated a
  730                          * MIC failure and has stripped the MIC.
  731                          * We may not have a key, so for now just
  732                          * return OK.
  733                          */
  734                         return (1);
  735                 }
  736         }
  737 
  738         /*
  739          * If we don't have a key at this point then we don't
  740          * have to demic anything.
  741          */
  742         if (k == NULL)
  743                 return (1);
  744 
  745         cip = k->wk_cipher;
  746         return (cip->ic_miclen > 0 ? cip->ic_demic(k, m, force) : 1);
  747 }
  748 
  749 
  750 static void
  751 load_ucastkey(void *arg, struct ieee80211_node *ni)
  752 {
  753         struct ieee80211vap *vap = ni->ni_vap;
  754         struct ieee80211_key *k;
  755 
  756         if (vap->iv_state != IEEE80211_S_RUN)
  757                 return;
  758         k = &ni->ni_ucastkey;
  759         if (k->wk_flags & IEEE80211_KEY_DEVKEY)
  760                 dev_key_set(vap, k);
  761 }
  762 
  763 /*
  764  * Re-load all keys known to the 802.11 layer that may
  765  * have hardware state backing them.  This is used by
  766  * drivers on resume to push keys down into the device.
  767  */
  768 void
  769 ieee80211_crypto_reload_keys(struct ieee80211com *ic)
  770 {
  771         struct ieee80211vap *vap;
  772         int i;
  773 
  774         /*
  775          * Keys in the global key table of each vap.
  776          */
  777         /* NB: used only during resume so don't lock for now */
  778         TAILQ_FOREACH(vap, &ic->ic_vaps, iv_next) {
  779                 if (vap->iv_state != IEEE80211_S_RUN)
  780                         continue;
  781                 for (i = 0; i < IEEE80211_WEP_NKID; i++) {
  782                         const struct ieee80211_key *k = &vap->iv_nw_keys[i];
  783                         if (k->wk_flags & IEEE80211_KEY_DEVKEY)
  784                                 dev_key_set(vap, k);
  785                 }
  786         }
  787         /*
  788          * Unicast keys.
  789          */
  790         ieee80211_iterate_nodes(&ic->ic_sta, load_ucastkey, NULL);
  791 }
  792 
  793 /*
  794  * Set the default key index for WEP, or KEYIX_NONE for no default TX key.
  795  *
  796  * This should be done as part of a key update block (iv_key_update_begin /
  797  * iv_key_update_end.)
  798  */
  799 void
  800 ieee80211_crypto_set_deftxkey(struct ieee80211vap *vap, ieee80211_keyix kid)
  801 {
  802 
  803         /* XXX TODO: assert we're in a key update block */
  804 
  805         vap->iv_update_deftxkey(vap, kid);
  806 }

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