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Relearn how WPA keying is supposed to work and fix WPA+WME while

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we're at it:
o WPA/802.11i has a unicast key and a group key; in station mode
  everything is sent with the unicast key--we were consulting the
  destination mac address and incorrectly using the group key
o (perpetuate fallback use of the default tx key to maintain
  compatibility with the way wpa_supplicant works)
o correct EAPOL encryption logic to check unicast key instead
  of assuming other state implies this
o move QoS encapsulation up to before enmic work so TKIP has the
  information required to calculate the pseudo-header
o do not do QoS-encapsulation of EAPOL frames as some ap's do the
  wrong thing with such frames (may need to revisit this if ap's
  start dropping non-QoS frames from stations assoc'd with QoS)
o move ieee80211_mbuf_adjust closer to its caller
This commit is contained in:
sam 2004-12-31 21:54:53 +00:00
parent 5a21ccb974
commit 7c448457f6
2 changed files with 129 additions and 111 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
sys/net80211/ieee80211_ioctl.h
View File

@ -167,6 +167,7 @@ struct ieee80211_stats {
u_int32_t is_crypto_attachfail; /* cipher attach failed */
u_int32_t is_crypto_swfallback; /* cipher fallback to s/w */
u_int32_t is_crypto_keyfail; /* driver key alloc failed */
u_int32_t is_crypto_enmicfail; /* en-MIC failed */
u_int32_t is_ibss_capmismatch; /* merge failed-cap mismatch */
u_int32_t is_ibss_norate; /* merge failed-rate mismatch */
u_int32_t is_ps_unassoc; /* ps-poll for unassoc. sta */

239
sys/net80211/ieee80211_output.c
View File

@ -203,73 +203,6 @@ ieee80211_send_nulldata(struct ieee80211com *ic, struct ieee80211_node *ni)
return 0;
}
/*
* Insure there is sufficient contiguous space to encapsulate the
* 802.11 data frame. If room isn't already there, arrange for it.
* Drivers and cipher modules assume we have done the necessary work
* and fail rudely if they don't find the space they need.
*/
static struct mbuf *
ieee80211_mbuf_adjust(struct ieee80211com *ic, int hdrsize,
struct ieee80211_key *key, struct mbuf *m)
{
#define TO_BE_RECLAIMED (sizeof(struct ether_header) - sizeof(struct llc))
int needed_space = hdrsize;
if (key != NULL) {
/* XXX belongs in crypto code? */
needed_space += key->wk_cipher->ic_header;
/* XXX frags */
}
/*
* We know we are called just before stripping an Ethernet
* header and prepending an LLC header. This means we know
* there will be
* sizeof(struct ether_header) - sizeof(struct llc)
* bytes recovered to which we need additional space for the
* 802.11 header and any crypto header.
*/
if (M_LEADINGSPACE(m) < needed_space - TO_BE_RECLAIMED) {
struct mbuf *n = m_gethdr(M_NOWAIT, m->m_type);
if (n == NULL) {
IEEE80211_DPRINTF(ic, IEEE80211_MSG_OUTPUT,
"%s: cannot expand storage\n", __func__);
ic->ic_stats.is_tx_nobuf++;
m_freem(m);
return NULL;
}
KASSERT(needed_space <= MHLEN,
("not enough room, need %u got %zu\n", needed_space, MHLEN));
/*
* Setup new mbuf to have leading space to prepend the
* 802.11 header and any crypto header bits that are
* required (the latter are added when the driver calls
* back to ieee80211_crypto_encap to do crypto encapsulation).
*/
/* NB: must be first 'cuz it clobbers m_data */
m_move_pkthdr(n, m);
n->m_len = 0; /* NB: m_gethdr does not set */
n->m_data += needed_space;
/*
* Pull up Ethernet header to create the expected layout.
* We could use m_pullup but that's overkill (i.e. we don't
* need the actual data) and it cannot fail so do it inline
* for speed.
*/
/* NB: struct ether_header is known to be contiguous */
n->m_len += sizeof(struct ether_header);
m->m_len -= sizeof(struct ether_header);
m->m_data += sizeof(struct ether_header);
/*
* Replace the head of the chain.
*/
n->m_next = m;
m = n;
}
return m;
#undef TO_BE_RECLAIMED
}
/*
* Assign priority to a frame based on any vlan tag assigned
* to the station and/or any Diffserv setting in an IP header.
@ -387,34 +320,104 @@ ieee80211_classify(struct ieee80211com *ic, struct mbuf *m, struct ieee80211_nod
}
/*
* Return the transmit key to use in sending a frame to the specified
* destination. Multicast traffic always uses the group key which is
* installed the default tx key. Otherwise if a unicast key is set
* we use that. When no unicast key is set we fall back to the default
* transmit key unless WPA is enabled in which case there should be
* a unicast frame so we don't want to use a default key (which in
* this case is the group/multicast key).
* Insure there is sufficient contiguous space to encapsulate the
* 802.11 data frame. If room isn't already there, arrange for it.
* Drivers and cipher modules assume we have done the necessary work
* and fail rudely if they don't find the space they need.
*/
static struct mbuf *
ieee80211_mbuf_adjust(struct ieee80211com *ic, int hdrsize,
struct ieee80211_key *key, struct mbuf *m)
{
#define TO_BE_RECLAIMED (sizeof(struct ether_header) - sizeof(struct llc))
int needed_space = hdrsize;
if (key != NULL) {
/* XXX belongs in crypto code? */
needed_space += key->wk_cipher->ic_header;
/* XXX frags */
}
/*
* We know we are called just before stripping an Ethernet
* header and prepending an LLC header. This means we know
* there will be
* sizeof(struct ether_header) - sizeof(struct llc)
* bytes recovered to which we need additional space for the
* 802.11 header and any crypto header.
*/
/* XXX check trailing space and copy instead? */
if (M_LEADINGSPACE(m) < needed_space - TO_BE_RECLAIMED) {
struct mbuf *n = m_gethdr(M_NOWAIT, m->m_type);
if (n == NULL) {
IEEE80211_DPRINTF(ic, IEEE80211_MSG_OUTPUT,
"%s: cannot expand storage\n", __func__);
ic->ic_stats.is_tx_nobuf++;
m_freem(m);
return NULL;
}
KASSERT(needed_space <= MHLEN,
("not enough room, need %u got %zu\n", needed_space, MHLEN));
/*
* Setup new mbuf to have leading space to prepend the
* 802.11 header and any crypto header bits that are
* required (the latter are added when the driver calls
* back to ieee80211_crypto_encap to do crypto encapsulation).
*/
/* NB: must be first 'cuz it clobbers m_data */
m_move_pkthdr(n, m);
n->m_len = 0; /* NB: m_gethdr does not set */
n->m_data += needed_space;
/*
* Pull up Ethernet header to create the expected layout.
* We could use m_pullup but that's overkill (i.e. we don't
* need the actual data) and it cannot fail so do it inline
* for speed.
*/
/* NB: struct ether_header is known to be contiguous */
n->m_len += sizeof(struct ether_header);
m->m_len -= sizeof(struct ether_header);
m->m_data += sizeof(struct ether_header);
/*
* Replace the head of the chain.
*/
n->m_next = m;
m = n;
}
return m;
#undef TO_BE_RECLAIMED
}
#define KEY_UNDEFINED(k) ((k).wk_cipher == &ieee80211_cipher_none)
/*
* Return the transmit key to use in sending a unicast frame.
* If a unicast key is set we use that. When no unicast key is set
* we fall back to the default transmit key.
*/
static __inline struct ieee80211_key *
ieee80211_crypto_getkey(struct ieee80211com *ic,
const u_int8_t mac[IEEE80211_ADDR_LEN], struct ieee80211_node *ni)
ieee80211_crypto_getucastkey(struct ieee80211com *ic, struct ieee80211_node *ni)
{
#define KEY_UNDEFINED(k) ((k).wk_cipher == &ieee80211_cipher_none)
if (IEEE80211_IS_MULTICAST(mac)) {
if (KEY_UNDEFINED(ni->ni_ucastkey)) {
if (ic->ic_def_txkey == IEEE80211_KEYIX_NONE ||
KEY_UNDEFINED(ic->ic_nw_keys[ic->ic_def_txkey]))
return NULL;
return &ic->ic_nw_keys[ic->ic_def_txkey];
} else if (KEY_UNDEFINED(ni->ni_ucastkey)) {
if ((ic->ic_flags & IEEE80211_F_WPA) ||
ic->ic_def_txkey == IEEE80211_KEYIX_NONE ||
KEY_UNDEFINED(ic->ic_nw_keys[ic->ic_def_txkey]))
return NULL;
return &ic->ic_nw_keys[ic->ic_def_txkey];
} else {
return &ni->ni_ucastkey;
}
#undef KEY_UNDEFINED
}
/*
* Return the transmit key to use in sending a multicast frame.
* Multicast traffic always uses the group key which is installed as
* the default tx key.
*/
static __inline struct ieee80211_key *
ieee80211_crypto_getmcastkey(struct ieee80211com *ic, struct ieee80211_node *ni)
{
if (ic->ic_def_txkey == IEEE80211_KEYIX_NONE ||
KEY_UNDEFINED(ic->ic_nw_keys[ic->ic_def_txkey]))
return NULL;
return &ic->ic_nw_keys[ic->ic_def_txkey];
}
/*
@ -431,7 +434,7 @@ ieee80211_encap(struct ieee80211com *ic, struct mbuf *m,
struct ieee80211_frame *wh;
struct ieee80211_key *key;
struct llc *llc;
int hdrsize, datalen;
int hdrsize, datalen, addqos;
KASSERT(m->m_len >= sizeof(eh), ("no ethernet header!"));
memcpy(&eh, mtod(m, caddr_t), sizeof(struct ether_header));
@ -449,17 +452,31 @@ ieee80211_encap(struct ieee80211com *ic, struct mbuf *m,
* routines, but they will/should discard it.
*/
if (ic->ic_flags & IEEE80211_F_PRIVACY) {
key = ieee80211_crypto_getkey(ic, eh.ether_dhost, ni);
if (ic->ic_opmode == IEEE80211_M_STA ||
!IEEE80211_IS_MULTICAST(eh.ether_dhost))
key = ieee80211_crypto_getucastkey(ic, ni);
else
key = ieee80211_crypto_getmcastkey(ic, ni);
if (key == NULL && eh.ether_type != htons(ETHERTYPE_PAE)) {
IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
"[%s] no default transmit key\n",
ether_sprintf(ni->ni_macaddr));
/* XXX statistic */
"[%s] no default transmit key (%s) deftxkey %u\n",
ether_sprintf(eh.ether_dhost), __func__,
ic->ic_def_txkey);
ic->ic_stats.is_tx_nodefkey++;
}
} else
key = NULL;
/* XXX 4-address format */
if (ni->ni_flags & IEEE80211_NODE_QOS)
/*
* XXX Some ap's don't handle QoS-encapsulated EAPOL
* frames so suppress use. This may be an issue if other
* ap's require all data frames to be QoS-encapsulated
* once negotiated in which case we'll need to make this
* configurable.
*/
addqos = (ni->ni_flags & IEEE80211_NODE_QOS) &&
eh.ether_type != htons(ETHERTYPE_PAE);
if (addqos)
hdrsize = sizeof(struct ieee80211_qosframe);
else
hdrsize = sizeof(struct ieee80211_frame);
@ -513,26 +530,7 @@ ieee80211_encap(struct ieee80211com *ic, struct mbuf *m,
case IEEE80211_M_MONITOR:
goto bad;
}
if (eh.ether_type != htons(ETHERTYPE_PAE) ||
(key != NULL && (ic->ic_flags & IEEE80211_F_WPA))) {
/*
* IEEE 802.1X: send EAPOL frames always in the clear.
* WPA/WPA2: encrypt EAPOL keys when pairwise keys are set.
*/
if (key != NULL) {
wh->i_fc[1] |= IEEE80211_FC1_WEP;
/* XXX do fragmentation */
if (!ieee80211_crypto_enmic(ic, key, m)) {
IEEE80211_DPRINTF(ic, IEEE80211_MSG_OUTPUT,
"[%s] enmic failed, discard frame\n",
ether_sprintf(eh.ether_dhost));
/* XXX statistic */
goto bad;
}
}
}
if (ni->ni_flags & IEEE80211_NODE_QOS) {
if (addqos) {
struct ieee80211_qosframe *qwh =
(struct ieee80211_qosframe *) wh;
int ac, tid;
@ -554,6 +552,25 @@ ieee80211_encap(struct ieee80211com *ic, struct mbuf *m,
htole16(ni->ni_txseqs[0] << IEEE80211_SEQ_SEQ_SHIFT);
ni->ni_txseqs[0]++;
}
if (key != NULL) {
/*
* IEEE 802.1X: send EAPOL frames always in the clear.
* WPA/WPA2: encrypt EAPOL keys when pairwise keys are set.
*/
if (eh.ether_type != htons(ETHERTYPE_PAE) ||
((ic->ic_flags & IEEE80211_F_WPA) &&
!KEY_UNDEFINED(ni->ni_ucastkey))) {
wh->i_fc[1] |= IEEE80211_FC1_WEP;
/* XXX do fragmentation */
if (!ieee80211_crypto_enmic(ic, key, m)) {
IEEE80211_DPRINTF(ic, IEEE80211_MSG_OUTPUT,
"[%s] enmic failed, discard frame\n",
ether_sprintf(eh.ether_dhost));
ic->ic_stats.is_crypto_enmicfail++;
goto bad;
}
}
}
IEEE80211_NODE_STAT(ni, tx_data);
IEEE80211_NODE_STAT_ADD(ni, tx_bytes, datalen);