/*- * Copyright (c) 2001 Atsushi Onoe * Copyright (c) 2002-2008 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. * * 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 __FBSDID("$FreeBSD$"); /* * IEEE 802.11 generic crypto support. */ #include "opt_wlan.h" #include #include #include #include #include #include #include #include /* XXX ETHER_HDR_LEN */ #include MALLOC_DEFINE(M_80211_CRYPTO, "80211crypto", "802.11 crypto state"); static int _ieee80211_crypto_delkey(struct ieee80211vap *, struct ieee80211_key *); /* * Table of registered cipher modules. */ static const struct ieee80211_cipher *ciphers[IEEE80211_CIPHER_MAX]; /* * Default "null" key management routines. */ static int null_key_alloc(struct ieee80211vap *vap, struct ieee80211_key *k, ieee80211_keyix *keyix, ieee80211_keyix *rxkeyix) { if (!(&vap->iv_nw_keys[0] <= k && k < &vap->iv_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 - vap->iv_nw_keys; } *rxkeyix = IEEE80211_KEYIX_NONE; /* XXX maybe *keyix? */ return 1; } static int null_key_delete(struct ieee80211vap *vap, const struct ieee80211_key *k) { return 1; } static int null_key_set(struct ieee80211vap *vap, const struct ieee80211_key *k, const uint8_t mac[IEEE80211_ADDR_LEN]) { return 1; } static void null_key_update(struct ieee80211vap *vap) {} /* * 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 int dev_key_alloc(struct ieee80211vap *vap, struct ieee80211_key *key, ieee80211_keyix *keyix, ieee80211_keyix *rxkeyix) { return vap->iv_key_alloc(vap, key, keyix, rxkeyix); } static __inline int dev_key_delete(struct ieee80211vap *vap, const struct ieee80211_key *key) { return vap->iv_key_delete(vap, key); } static __inline int dev_key_set(struct ieee80211vap *vap, const struct ieee80211_key *key) { return vap->iv_key_set(vap, key, key->wk_macaddr); } /* * 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; } /* * Teardown crypto support. */ void ieee80211_crypto_detach(struct ieee80211com *ic) { } /* * Setup crypto support for a vap. */ void ieee80211_crypto_vattach(struct ieee80211vap *vap) { int i; /* NB: we assume everything is pre-zero'd */ vap->iv_max_keyix = IEEE80211_WEP_NKID; 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; } /* * Teardown crypto support for a vap. */ void ieee80211_crypto_vdetach(struct ieee80211vap *vap) { ieee80211_crypto_delglobalkeys(vap); } /* * 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[IEEE80211_CIPHER_MAX] = { [IEEE80211_CIPHER_WEP] = "wlan_wep", [IEEE80211_CIPHER_TKIP] = "wlan_tkip", [IEEE80211_CIPHER_AES_OCB] = "wlan_aes_ocb", [IEEE80211_CIPHER_AES_CCM] = "wlan_ccmp", [IEEE80211_CIPHER_TKIPMIC] = "#4", /* NB: reserved */ [IEEE80211_CIPHER_CKIP] = "wlan_ckip", [IEEE80211_CIPHER_NONE] = "wlan_none", }; /* NB: there must be no overlap between user-supplied and device-owned flags */ CTASSERT((IEEE80211_KEY_COMMON & IEEE80211_KEY_DEVICE) == 0); /* * 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. * * 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) { struct ieee80211com *ic = vap->iv_ic; const struct ieee80211_cipher *cip; ieee80211_keyix keyix, rxkeyix; void *keyctx; int oflags; IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, "%s: cipher %u flags 0x%x keyix %u\n", __func__, cipher, flags, key->wk_keyix); /* * 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) { /* * 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_. */ 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. */ cip = ciphers[cipher]; if (cip == NULL) { IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, "%s: unable to load cipher %u, module %s\n", __func__, cipher, cipher_modnames[cipher]); vap->iv_stats.is_crypto_nocipher++; return 0; } } oflags = key->wk_flags; flags &= IEEE80211_KEY_COMMON; /* NB: preserve device attributes */ flags |= (oflags & IEEE80211_KEY_DEVICE); /* * If the hardware does not support the cipher then * fallback to a host-based implementation. */ if ((ic->ic_cryptocaps & (1<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_cryptocaps & IEEE80211_CRYPTO_TKIPMIC) == 0) { 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; } /* * 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) { /* * Fillin the flags so cipher modules can see s/w * crypto requirements and potentially allocate * different state and/or attach different method * pointers. */ 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; } /* * 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_flags & IEEE80211_KEY_DEVKEY) == 0) { if (!dev_key_alloc(vap, key, &keyix, &rxkeyix)) { /* * Unable to setup driver state. */ 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; } if (key->wk_flags != flags) { /* * Driver overrode flags we setup; typically because * resources were unavailable to handle _this_ key. * Re-attach the cipher context to allow cipher * modules to handle differing requirements. */ IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, "%s: driver override for cipher %s, flags " "0x%x -> 0x%x\n", __func__, cip->ic_name, oflags, key->wk_flags); keyctx = cip->ic_attach(vap, key); if (keyctx == NULL) { IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, "%s: unable to attach cipher %s with " "flags 0x%x\n", __func__, cip->ic_name, key->wk_flags); 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; } key->wk_keyix = keyix; key->wk_rxkeyix = rxkeyix; key->wk_flags |= IEEE80211_KEY_DEVKEY; } return 1; } /* * Remove the key (no locking, for internal use). */ static int _ieee80211_crypto_delkey(struct ieee80211vap *vap, struct ieee80211_key *key) { KASSERT(key->wk_cipher != NULL, ("No cipher!")); IEEE80211_DPRINTF(vap, 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[IEEE80211_NONQOS_TID], key->wk_keytsc, key->wk_keylen); if (key->wk_flags & IEEE80211_KEY_DEVKEY) { /* * Remove hardware entry. */ /* XXX key cache */ if (!dev_key_delete(vap, key)) { IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, "%s: driver did not delete key index %u\n", __func__, key->wk_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) { int status; ieee80211_key_update_begin(vap); status = _ieee80211_crypto_delkey(vap, key); ieee80211_key_update_end(vap); return status; } /* * 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(vap, &vap->iv_nw_keys[i]); ieee80211_key_update_end(vap); } /* * 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 struct ieee80211_cipher *cip = key->wk_cipher; KASSERT(cip != NULL, ("No cipher!")); IEEE80211_DPRINTF(vap, 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(key->wk_macaddr), key->wk_keyrsc[IEEE80211_NONQOS_TID], key->wk_keytsc, key->wk_keylen); if ((key->wk_flags & IEEE80211_KEY_DEVKEY) == 0) { /* XXX nothing allocated, should not happen */ IEEE80211_DPRINTF(vap, IEEE80211_MSG_CRYPTO, "%s: no device key setup done; should not happen!\n", __func__); vap->iv_stats.is_crypto_setkey_nokey++; return 0; } /* * 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; } return dev_key_set(vap, key); } /* * Add privacy headers appropriate for the specified key. */ struct ieee80211_key * ieee80211_crypto_encap(struct ieee80211_node *ni, struct mbuf *m) { struct ieee80211vap *vap = ni->ni_vap; struct ieee80211_key *k; struct ieee80211_frame *wh; const struct ieee80211_cipher *cip; uint8_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 (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; 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 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 ieee80211vap *vap = ni->ni_vap; struct ieee80211_key *k; struct ieee80211_frame *wh; const struct ieee80211_cipher *cip; uint8_t keyid; /* NB: this minimum size data frame could be bigger */ if (m->m_pkthdr.len < IEEE80211_WEP_MINLEN) { IEEE80211_DPRINTF(vap, IEEE80211_MSG_ANY, "%s: WEP data frame too short, len %u\n", __func__, m->m_pkthdr.len); vap->iv_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 *); m_copydata(m, hdrlen + IEEE80211_WEP_IVLEN, sizeof(keyid), &keyid); if (IEEE80211_IS_MULTICAST(wh->i_addr1) || IEEE80211_KEY_UNDEFINED(&ni->ni_ucastkey)) k = &vap->iv_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_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2, "unable to pullup %s header", cip->ic_name); vap->iv_stats.is_rx_wepfail++; /* XXX */ return NULL; } return (cip->ic_decap(k, m, hdrlen) ? k : NULL); #undef IEEE80211_WEP_MINLEN #undef IEEE80211_WEP_HDRLEN } static void load_ucastkey(void *arg, struct ieee80211_node *ni) { struct ieee80211vap *vap = ni->ni_vap; struct ieee80211_key *k; if (vap->iv_state != IEEE80211_S_RUN) return; k = &ni->ni_ucastkey; if (k->wk_flags & IEEE80211_KEY_DEVKEY) dev_key_set(vap, k); } /* * Re-load all keys known to the 802.11 layer that may * have hardware state backing them. This is used by * drivers on resume to push keys down into the device. */ void ieee80211_crypto_reload_keys(struct ieee80211com *ic) { struct ieee80211vap *vap; int i; /* * Keys in the global key table of each vap. */ /* NB: used only during resume so don't lock for now */ TAILQ_FOREACH(vap, &ic->ic_vaps, iv_next) { if (vap->iv_state != IEEE80211_S_RUN) continue; for (i = 0; i < IEEE80211_WEP_NKID; i++) { const struct ieee80211_key *k = &vap->iv_nw_keys[i]; if (k->wk_flags & IEEE80211_KEY_DEVKEY) dev_key_set(vap, k); } } /* * Unicast keys. */ ieee80211_iterate_nodes(&ic->ic_sta, load_ucastkey, NULL); }