d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
d677d4be0c
freebsd-dev/sys/net80211/ieee80211_input.c
Mathy Vanhoef f024bdf115 net80211: mitigation against A-MSDU design flaw 
Mitigate A-MSDU injection attacks by detecting if the destination address
of a subframe equals an RFC1042 (i.e., LLC/SNAP) header, and if so
dropping the complete A-MSDU frame.  This mitigates known attacks,
although new (unknown) aggregation-based attacks may remain possible.

This defense works because in A-MSDU aggregation injection attacks, a
normal encrypted Wi-Fi frame is turned into an A-MSDU frame. This means
the first 6 bytes of the first A-MSDU subframe correspond to an RFC1042
header. In other words, the destination MAC address of the first A-MSDU
subframe contains the start of an RFC1042 header during an aggregation
attack. We can detect this and thereby prevent this specific attack.

This relates to section 7.2 in the 2021 Usenix "FragAttacks" (Fragment
and Forge: Breaking Wi-Fi Through Frame Aggregation and Fragmentation)
paper.

Submitted by:	Mathy Vanhoef (Mathy.Vanhoef kuleuven.be)
Security:	CVE-2020-24588
PR:		256119
Differential Revision: https://reviews.freebsd.org/D30664
2021-09-30 14:50:45 +00:00

1032 lines
28 KiB
C
Raw Blame History

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2001 Atsushi Onoe
* Copyright (c) 2002-2009 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_wlan.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/endian.h>
#include <sys/kernel.h>
#include <sys/socket.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <net/if_var.h>
#include <net/if_llc.h>
#include <net/if_media.h>
#include <net/if_vlan_var.h>
#include <net80211/ieee80211_var.h>
#include <net80211/ieee80211_input.h>
#ifdef IEEE80211_SUPPORT_MESH
#include <net80211/ieee80211_mesh.h>
#endif
#include <net/bpf.h>
#ifdef INET
#include <netinet/in.h>
#include <net/ethernet.h>
#endif
static void
ieee80211_process_mimo(struct ieee80211_node *ni, struct ieee80211_rx_stats *rx)
{
int i;
/* Verify the required MIMO bits are set */
if ((rx->r_flags & (IEEE80211_R_C_CHAIN | IEEE80211_R_C_NF | IEEE80211_R_C_RSSI)) !=
(IEEE80211_R_C_CHAIN | IEEE80211_R_C_NF | IEEE80211_R_C_RSSI))
return;
/* XXX This assumes the MIMO radios have both ctl and ext chains */
for (i = 0; i < MIN(rx->c_chain, IEEE80211_MAX_CHAINS); i++) {
IEEE80211_RSSI_LPF(ni->ni_mimo_rssi_ctl[i], rx->c_rssi_ctl[i]);
IEEE80211_RSSI_LPF(ni->ni_mimo_rssi_ext[i], rx->c_rssi_ext[i]);
}
/* XXX This also assumes the MIMO radios have both ctl and ext chains */
for(i = 0; i < MIN(rx->c_chain, IEEE80211_MAX_CHAINS); i++) {
ni->ni_mimo_noise_ctl[i] = rx->c_nf_ctl[i];
ni->ni_mimo_noise_ext[i] = rx->c_nf_ext[i];
}
ni->ni_mimo_chains = rx->c_chain;
}
int
ieee80211_input_mimo(struct ieee80211_node *ni, struct mbuf *m)
{
struct ieee80211_rx_stats rxs;
/* try to read stats from mbuf */
bzero(&rxs, sizeof(rxs));
if (ieee80211_get_rx_params(m, &rxs) != 0)
return (-1);
/* XXX should assert IEEE80211_R_NF and IEEE80211_R_RSSI are set */
ieee80211_process_mimo(ni, &rxs);
//return ieee80211_input(ni, m, rx->rssi, rx->nf);
return ni->ni_vap->iv_input(ni, m, &rxs, rxs.c_rssi, rxs.c_nf);
}
int
ieee80211_input_all(struct ieee80211com *ic, struct mbuf *m, int rssi, int nf)
{
struct ieee80211_rx_stats rx;
rx.r_flags = IEEE80211_R_NF | IEEE80211_R_RSSI;
rx.c_nf = nf;
rx.c_rssi = rssi;
if (!ieee80211_add_rx_params(m, &rx))
return (-1);
return ieee80211_input_mimo_all(ic, m);
}
int
ieee80211_input_mimo_all(struct ieee80211com *ic, struct mbuf *m)
{
struct ieee80211vap *vap;
int type = -1;
m->m_flags |= M_BCAST; /* NB: mark for bpf tap'ing */
/* XXX locking */
TAILQ_FOREACH(vap, &ic->ic_vaps, iv_next) {
struct ieee80211_node *ni;
struct mbuf *mcopy;
/* NB: could check for IFF_UP but this is cheaper */
if (vap->iv_state == IEEE80211_S_INIT)
continue;
/*
* WDS vap's only receive directed traffic from the
* station at the ``far end''. That traffic should
* be passed through the AP vap the station is associated
* to--so don't spam them with mcast frames.
*/
if (vap->iv_opmode == IEEE80211_M_WDS)
continue;
if (TAILQ_NEXT(vap, iv_next) != NULL) {
/*
* Packet contents are changed by ieee80211_decap
* so do a deep copy of the packet.
* NB: tags are copied too.
*/
mcopy = m_dup(m, M_NOWAIT);
if (mcopy == NULL) {
/* XXX stat+msg */
continue;
}
} else {
mcopy = m;
m = NULL;
}
ni = ieee80211_ref_node(vap->iv_bss);
type = ieee80211_input_mimo(ni, mcopy);
ieee80211_free_node(ni);
}
if (m != NULL) /* no vaps, reclaim mbuf */
m_freem(m);
return type;
}
/*
* This function reassembles fragments.
*
* XXX should handle 3 concurrent reassemblies per-spec.
*/
struct mbuf *
ieee80211_defrag(struct ieee80211_node *ni, struct mbuf *m, int hdrspace,
int has_decrypted)
{
struct ieee80211vap *vap = ni->ni_vap;
struct ieee80211_frame *wh = mtod(m, struct ieee80211_frame *);
struct ieee80211_frame *lwh;
uint16_t rxseq;
uint8_t fragno;
uint8_t more_frag = wh->i_fc[1] & IEEE80211_FC1_MORE_FRAG;
struct mbuf *mfrag;
KASSERT(!IEEE80211_IS_MULTICAST(wh->i_addr1), ("multicast fragm?"));
rxseq = le16toh(*(uint16_t *)wh->i_seq);
fragno = rxseq & IEEE80211_SEQ_FRAG_MASK;
/* Quick way out, if there's nothing to defragment */
if (!more_frag && fragno == 0 && ni->ni_rxfrag[0] == NULL)
return m;
/* Temporarily set flag to remember if fragment was encrypted. */
/* XXX use a non-packet altering storage for this in the future. */
if (has_decrypted)
wh->i_fc[1] |= IEEE80211_FC1_PROTECTED;
/*
* Remove frag to insure it doesn't get reaped by timer.
*/
if (ni->ni_table == NULL) {
/*
* Should never happen. If the node is orphaned (not in
* the table) then input packets should not reach here.
* Otherwise, a concurrent request that yanks the table
* should be blocked by other interlocking and/or by first
* shutting the driver down. Regardless, be defensive
* here and just bail
*/
/* XXX need msg+stat */
m_freem(m);
return NULL;
}
IEEE80211_NODE_LOCK(ni->ni_table);
mfrag = ni->ni_rxfrag[0];
ni->ni_rxfrag[0] = NULL;
IEEE80211_NODE_UNLOCK(ni->ni_table);
/*
* Validate new fragment is in order and
* related to the previous ones.
*/
if (mfrag != NULL) {
uint16_t last_rxseq;
lwh = mtod(mfrag, struct ieee80211_frame *);
last_rxseq = le16toh(*(uint16_t *)lwh->i_seq);
/*
* NB: check seq # and frag together. Also check that both
* fragments are plaintext or that both are encrypted.
*/
if (rxseq == last_rxseq+1 &&
IEEE80211_ADDR_EQ(wh->i_addr1, lwh->i_addr1) &&
IEEE80211_ADDR_EQ(wh->i_addr2, lwh->i_addr2) &&
!((wh->i_fc[1] ^ lwh->i_fc[1]) & IEEE80211_FC1_PROTECTED)) {
/* XXX clear MORE_FRAG bit? */
/* track last seqnum and fragno */
*(uint16_t *) lwh->i_seq = *(uint16_t *) wh->i_seq;
m_adj(m, hdrspace); /* strip header */
m_catpkt(mfrag, m); /* concatenate */
} else {
/*
* Unrelated fragment or no space for it,
* clear current fragments.
*/
m_freem(mfrag);
mfrag = NULL;
}
}
if (mfrag == NULL) {
if (fragno != 0) { /* !first fragment, discard */
vap->iv_stats.is_rx_defrag++;
IEEE80211_NODE_STAT(ni, rx_defrag);
m_freem(m);
return NULL;
}
mfrag = m;
}
if (more_frag) { /* more to come, save */
ni->ni_rxfragstamp = ticks;
ni->ni_rxfrag[0] = mfrag;
mfrag = NULL;
}
/* Remember to clear protected flag that was temporarily set. */
if (mfrag != NULL) {
wh = mtod(mfrag, struct ieee80211_frame *);
wh->i_fc[1] &= ~IEEE80211_FC1_PROTECTED;
}
return mfrag;
}
void
ieee80211_deliver_data(struct ieee80211vap *vap,
struct ieee80211_node *ni, struct mbuf *m)
{
struct ether_header *eh = mtod(m, struct ether_header *);
struct ifnet *ifp = vap->iv_ifp;
/* clear driver/net80211 flags before passing up */
m->m_flags &= ~(M_MCAST | M_BCAST);
m_clrprotoflags(m);
/* NB: see hostap_deliver_data, this path doesn't handle hostap */
KASSERT(vap->iv_opmode != IEEE80211_M_HOSTAP, ("gack, hostap"));
/*
* Do accounting.
*/
if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
IEEE80211_NODE_STAT(ni, rx_data);
IEEE80211_NODE_STAT_ADD(ni, rx_bytes, m->m_pkthdr.len);
if (ETHER_IS_MULTICAST(eh->ether_dhost)) {
if (ETHER_IS_BROADCAST(eh->ether_dhost))
m->m_flags |= M_BCAST;
else
m->m_flags |= M_MCAST;
IEEE80211_NODE_STAT(ni, rx_mcast);
} else
IEEE80211_NODE_STAT(ni, rx_ucast);
m->m_pkthdr.rcvif = ifp;
if (ni->ni_vlan != 0) {
/* attach vlan tag */
m->m_pkthdr.ether_vtag = ni->ni_vlan;
m->m_flags |= M_VLANTAG;
}
ifp->if_input(ifp, m);
}
struct mbuf *
ieee80211_decap(struct ieee80211vap *vap, struct mbuf *m, int hdrlen,
uint8_t qos)
{
struct ieee80211_qosframe_addr4 wh;
struct ether_header *eh;
struct llc *llc;
KASSERT(hdrlen <= sizeof(wh),
("hdrlen %d > max %zd", hdrlen, sizeof(wh)));
if (m->m_len < hdrlen + sizeof(*llc) &&
(m = m_pullup(m, hdrlen + sizeof(*llc))) == NULL) {
vap->iv_stats.is_rx_tooshort++;
/* XXX msg */
return NULL;
}
memcpy(&wh, mtod(m, caddr_t), hdrlen);
llc = (struct llc *)(mtod(m, caddr_t) + hdrlen);
if (llc->llc_dsap == LLC_SNAP_LSAP && llc->llc_ssap == LLC_SNAP_LSAP &&
llc->llc_control == LLC_UI && llc->llc_snap.org_code[0] == 0 &&
llc->llc_snap.org_code[1] == 0 && llc->llc_snap.org_code[2] == 0 &&
/* NB: preserve AppleTalk frames that have a native SNAP hdr */
!(llc->llc_snap.ether_type == htons(ETHERTYPE_AARP) ||
llc->llc_snap.ether_type == htons(ETHERTYPE_IPX)) &&
/* Do not want to touch A-MSDU frames. */
!(qos & IEEE80211_QOS_AMSDU)) {
m_adj(m, hdrlen + sizeof(struct llc) - sizeof(*eh));
llc = NULL;
} else {
m_adj(m, hdrlen - sizeof(*eh));
}
eh = mtod(m, struct ether_header *);
switch (wh.i_fc[1] & IEEE80211_FC1_DIR_MASK) {
case IEEE80211_FC1_DIR_NODS:
IEEE80211_ADDR_COPY(eh->ether_dhost, wh.i_addr1);
IEEE80211_ADDR_COPY(eh->ether_shost, wh.i_addr2);
break;
case IEEE80211_FC1_DIR_TODS:
IEEE80211_ADDR_COPY(eh->ether_dhost, wh.i_addr3);
IEEE80211_ADDR_COPY(eh->ether_shost, wh.i_addr2);
break;
case IEEE80211_FC1_DIR_FROMDS:
IEEE80211_ADDR_COPY(eh->ether_dhost, wh.i_addr1);
IEEE80211_ADDR_COPY(eh->ether_shost, wh.i_addr3);
break;
case IEEE80211_FC1_DIR_DSTODS:
IEEE80211_ADDR_COPY(eh->ether_dhost, wh.i_addr3);
IEEE80211_ADDR_COPY(eh->ether_shost, wh.i_addr4);
break;
}
#ifndef __NO_STRICT_ALIGNMENT
if (!ALIGNED_POINTER(mtod(m, caddr_t) + sizeof(*eh), uint32_t)) {
m = ieee80211_realign(vap, m, sizeof(*eh));
if (m == NULL)
return NULL;
}
#endif /* !__NO_STRICT_ALIGNMENT */
if (llc != NULL) {
eh = mtod(m, struct ether_header *);
eh->ether_type = htons(m->m_pkthdr.len - sizeof(*eh));
}
return m;
}
/*
* Decap a frame encapsulated in a fast-frame/A-MSDU.
*/
struct mbuf *
ieee80211_decap1(struct mbuf *m, int *framelen)
{
#define FF_LLC_SIZE (sizeof(struct ether_header) + sizeof(struct llc))
struct ether_header *eh;
struct llc *llc;
const uint8_t llc_hdr_mac[ETHER_ADDR_LEN] = {
/* MAC address matching the 802.2 LLC header */
LLC_SNAP_LSAP, LLC_SNAP_LSAP, LLC_UI, 0, 0, 0
};
/*
* The frame has an 802.3 header followed by an 802.2
* LLC header. The encapsulated frame length is in the
* first header type field; save that and overwrite it
* with the true type field found in the second. Then
* copy the 802.3 header up to where it belongs and
* adjust the mbuf contents to remove the void.
*/
if (m->m_len < FF_LLC_SIZE && (m = m_pullup(m, FF_LLC_SIZE)) == NULL)
return NULL;
eh = mtod(m, struct ether_header *); /* 802.3 header is first */
/*
* Detect possible attack where a single 802.11 frame is processed
* as an A-MSDU frame due to an adversary setting the A-MSDU present
* bit in the 802.11 QoS header. [FragAttacks]
*/
if (memcmp(eh->ether_dhost, llc_hdr_mac, ETHER_ADDR_LEN) == 0)
return NULL;
llc = (struct llc *)&eh[1]; /* 802.2 header follows */
*framelen = ntohs(eh->ether_type) /* encap'd frame size */
+ sizeof(struct ether_header) - sizeof(struct llc);
eh->ether_type = llc->llc_un.type_snap.ether_type;
ovbcopy(eh, mtod(m, uint8_t *) + sizeof(struct llc),
sizeof(struct ether_header));
m_adj(m, sizeof(struct llc));
return m;
#undef FF_LLC_SIZE
}
/*
* Install received rate set information in the node's state block.
*/
int
ieee80211_setup_rates(struct ieee80211_node *ni,
const uint8_t *rates, const uint8_t *xrates, int flags)
{
struct ieee80211vap *vap = ni->ni_vap;
struct ieee80211_rateset *rs = &ni->ni_rates;
memset(rs, 0, sizeof(*rs));
rs->rs_nrates = rates[1];
memcpy(rs->rs_rates, rates + 2, rs->rs_nrates);
if (xrates != NULL) {
uint8_t nxrates;
/*
* Tack on 11g extended supported rate element.
*/
nxrates = xrates[1];
if (rs->rs_nrates + nxrates > IEEE80211_RATE_MAXSIZE) {
nxrates = IEEE80211_RATE_MAXSIZE - rs->rs_nrates;
IEEE80211_NOTE(vap, IEEE80211_MSG_XRATE, ni,
"extended rate set too large; only using "
"%u of %u rates", nxrates, xrates[1]);
vap->iv_stats.is_rx_rstoobig++;
}
memcpy(rs->rs_rates + rs->rs_nrates, xrates+2, nxrates);
rs->rs_nrates += nxrates;
}
return ieee80211_fix_rate(ni, rs, flags);
}
/*
* Send a management frame error response to the specified
* station. If ni is associated with the station then use
* it; otherwise allocate a temporary node suitable for
* transmitting the frame and then free the reference so
* it will go away as soon as the frame has been transmitted.
*/
void
ieee80211_send_error(struct ieee80211_node *ni,
const uint8_t mac[IEEE80211_ADDR_LEN], int subtype, int arg)
{
struct ieee80211vap *vap = ni->ni_vap;
int istmp;
if (ni == vap->iv_bss) {
if (vap->iv_state != IEEE80211_S_RUN) {
/*
* XXX hack until we get rid of this routine.
* We can be called prior to the vap reaching
* run state under certain conditions in which
* case iv_bss->ni_chan will not be setup.
* Check for this explicitly and and just ignore
* the request.
*/
return;
}
ni = ieee80211_tmp_node(vap, mac);
if (ni == NULL) {
/* XXX msg */
return;
}
istmp = 1;
} else
istmp = 0;
IEEE80211_SEND_MGMT(ni, subtype, arg);
if (istmp)
ieee80211_free_node(ni);
}
int
ieee80211_alloc_challenge(struct ieee80211_node *ni)
{
if (ni->ni_challenge == NULL)
ni->ni_challenge = (uint32_t *)
IEEE80211_MALLOC(IEEE80211_CHALLENGE_LEN,
M_80211_NODE, IEEE80211_M_NOWAIT);
if (ni->ni_challenge == NULL) {
IEEE80211_NOTE(ni->ni_vap,
IEEE80211_MSG_DEBUG | IEEE80211_MSG_AUTH, ni,
"%s", "shared key challenge alloc failed");
/* XXX statistic */
}
return (ni->ni_challenge != NULL);
}
/*
* Parse a Beacon or ProbeResponse frame and return the
* useful information in an ieee80211_scanparams structure.
* Status is set to 0 if no problems were found; otherwise
* a bitmask of IEEE80211_BPARSE_* items is returned that
* describes the problems detected.
*/
int
ieee80211_parse_beacon(struct ieee80211_node *ni, struct mbuf *m,
struct ieee80211_channel *rxchan, struct ieee80211_scanparams *scan)
{
struct ieee80211vap *vap = ni->ni_vap;
struct ieee80211com *ic = ni->ni_ic;
struct ieee80211_frame *wh;
uint8_t *frm, *efrm;
wh = mtod(m, struct ieee80211_frame *);
frm = (uint8_t *)&wh[1];
efrm = mtod(m, uint8_t *) + m->m_len;
scan->status = 0;
/*
* beacon/probe response frame format
*
* XXX Update from 802.11-2012 - eg where HT is
* [8] time stamp
* [2] beacon interval
* [2] capability information
* [tlv] ssid
* [tlv] supported rates
* [tlv] country information
* [tlv] channel switch announcement (CSA)
* [tlv] parameter set (FH/DS)
* [tlv] erp information
* [tlv] extended supported rates
* [tlv] WME
* [tlv] WPA or RSN
* [tlv] HT capabilities
* [tlv] HT information
* [tlv] VHT capabilities
* [tlv] VHT information
* [tlv] Atheros capabilities
* [tlv] Mesh ID
* [tlv] Mesh Configuration
*/
IEEE80211_VERIFY_LENGTH(efrm - frm, 12,
return (scan->status = IEEE80211_BPARSE_BADIELEN));
memset(scan, 0, sizeof(*scan));
scan->tstamp = frm; frm += 8;
scan->bintval = le16toh(*(uint16_t *)frm); frm += 2;
scan->capinfo = le16toh(*(uint16_t *)frm); frm += 2;
scan->bchan = ieee80211_chan2ieee(ic, rxchan);
scan->chan = scan->bchan;
scan->ies = frm;
scan->ies_len = efrm - frm;
while (efrm - frm > 1) {
IEEE80211_VERIFY_LENGTH(efrm - frm, frm[1] + 2,
return (scan->status = IEEE80211_BPARSE_BADIELEN));
switch (*frm) {
case IEEE80211_ELEMID_SSID:
scan->ssid = frm;
break;
case IEEE80211_ELEMID_RATES:
scan->rates = frm;
break;
case IEEE80211_ELEMID_COUNTRY:
scan->country = frm;
break;
case IEEE80211_ELEMID_CSA:
scan->csa = frm;
break;
case IEEE80211_ELEMID_QUIET:
scan->quiet = frm;
break;
case IEEE80211_ELEMID_FHPARMS:
if (ic->ic_phytype == IEEE80211_T_FH) {
scan->fhdwell = le16dec(&frm[2]);
scan->chan = IEEE80211_FH_CHAN(frm[4], frm[5]);
scan->fhindex = frm[6];
}
break;
case IEEE80211_ELEMID_DSPARMS:
/*
* XXX hack this since depending on phytype
* is problematic for multi-mode devices.
*/
if (ic->ic_phytype != IEEE80211_T_FH)
scan->chan = frm[2];
break;
case IEEE80211_ELEMID_TIM:
/* XXX ATIM? */
scan->tim = frm;
scan->timoff = frm - mtod(m, uint8_t *);
break;
case IEEE80211_ELEMID_IBSSPARMS:
case IEEE80211_ELEMID_CFPARMS:
case IEEE80211_ELEMID_PWRCNSTR:
case IEEE80211_ELEMID_BSSLOAD:
case IEEE80211_ELEMID_APCHANREP:
/* NB: avoid debugging complaints */
break;
case IEEE80211_ELEMID_XRATES:
scan->xrates = frm;
break;
case IEEE80211_ELEMID_ERP:
if (frm[1] != 1) {
IEEE80211_DISCARD_IE(vap,
IEEE80211_MSG_ELEMID, wh, "ERP",
"bad len %u", frm[1]);
vap->iv_stats.is_rx_elem_toobig++;
break;
}
scan->erp = frm[2] | 0x100;
break;
case IEEE80211_ELEMID_HTCAP:
scan->htcap = frm;
break;
case IEEE80211_ELEMID_VHT_CAP:
scan->vhtcap = frm;
break;
case IEEE80211_ELEMID_VHT_OPMODE:
scan->vhtopmode = frm;
break;
case IEEE80211_ELEMID_RSN:
scan->rsn = frm;
break;
case IEEE80211_ELEMID_HTINFO:
scan->htinfo = frm;
break;
#ifdef IEEE80211_SUPPORT_MESH
case IEEE80211_ELEMID_MESHID:
scan->meshid = frm;
break;
case IEEE80211_ELEMID_MESHCONF:
scan->meshconf = frm;
break;
#endif
/* Extended capabilities; nothing handles it for now */
case IEEE80211_ELEMID_EXTCAP:
break;
case IEEE80211_ELEMID_VENDOR:
if (iswpaoui(frm))
scan->wpa = frm;
else if (iswmeparam(frm) || iswmeinfo(frm))
scan->wme = frm;
#ifdef IEEE80211_SUPPORT_SUPERG
else if (isatherosoui(frm))
scan->ath = frm;
#endif
#ifdef IEEE80211_SUPPORT_TDMA
else if (istdmaoui(frm))
scan->tdma = frm;
#endif
else if (vap->iv_flags_ht & IEEE80211_FHT_HTCOMPAT) {
/*
* Accept pre-draft HT ie's if the
* standard ones have not been seen.
*/
if (ishtcapoui(frm)) {
if (scan->htcap == NULL)
scan->htcap = frm;
} else if (ishtinfooui(frm)) {
if (scan->htinfo == NULL)
scan->htcap = frm;
}
}
break;
default:
IEEE80211_DISCARD_IE(vap, IEEE80211_MSG_ELEMID,
wh, "unhandled",
"id %u, len %u", *frm, frm[1]);
vap->iv_stats.is_rx_elem_unknown++;
break;
}
frm += frm[1] + 2;
}
IEEE80211_VERIFY_ELEMENT(scan->rates, IEEE80211_RATE_MAXSIZE,
scan->status |= IEEE80211_BPARSE_RATES_INVALID);
if (scan->rates != NULL && scan->xrates != NULL) {
/*
* NB: don't process XRATES if RATES is missing. This
* avoids a potential null ptr deref and should be ok
* as the return code will already note RATES is missing
* (so callers shouldn't otherwise process the frame).
*/
IEEE80211_VERIFY_ELEMENT(scan->xrates,
IEEE80211_RATE_MAXSIZE - scan->rates[1],
scan->status |= IEEE80211_BPARSE_XRATES_INVALID);
}
IEEE80211_VERIFY_ELEMENT(scan->ssid, IEEE80211_NWID_LEN,
scan->status |= IEEE80211_BPARSE_SSID_INVALID);
if (scan->chan != scan->bchan && ic->ic_phytype != IEEE80211_T_FH) {
/*
* Frame was received on a channel different from the
* one indicated in the DS params element id;
* silently discard it.
*
* NB: this can happen due to signal leakage.
* But we should take it for FH phy because
* the rssi value should be correct even for
* different hop pattern in FH.
*/
IEEE80211_DISCARD(vap,
IEEE80211_MSG_ELEMID | IEEE80211_MSG_INPUT,
wh, NULL, "for off-channel %u (bchan=%u)",
scan->chan, scan->bchan);
vap->iv_stats.is_rx_chanmismatch++;
scan->status |= IEEE80211_BPARSE_OFFCHAN;
}
if (!(IEEE80211_BINTVAL_MIN <= scan->bintval &&
scan->bintval <= IEEE80211_BINTVAL_MAX)) {
IEEE80211_DISCARD(vap,
IEEE80211_MSG_ELEMID | IEEE80211_MSG_INPUT,
wh, NULL, "bogus beacon interval (%d TU)",
(int) scan->bintval);
vap->iv_stats.is_rx_badbintval++;
scan->status |= IEEE80211_BPARSE_BINTVAL_INVALID;
}
if (scan->country != NULL) {
/*
* Validate we have at least enough data to extract
* the country code. Not sure if we should return an
* error instead of discarding the IE; consider this
* being lenient as we don't depend on the data for
* correct operation.
*/
IEEE80211_VERIFY_LENGTH(scan->country[1], 3 * sizeof(uint8_t),
scan->country = NULL);
}
if (scan->csa != NULL) {
/*
* Validate Channel Switch Announcement; this must
* be the correct length or we toss the frame.
*/
IEEE80211_VERIFY_LENGTH(scan->csa[1], 3 * sizeof(uint8_t),
scan->status |= IEEE80211_BPARSE_CSA_INVALID);
}
/*
* Process HT ie's. This is complicated by our
* accepting both the standard ie's and the pre-draft
* vendor OUI ie's that some vendors still use/require.
*/
if (scan->htcap != NULL) {
IEEE80211_VERIFY_LENGTH(scan->htcap[1],
scan->htcap[0] == IEEE80211_ELEMID_VENDOR ?
4 + sizeof(struct ieee80211_ie_htcap)-2 :
sizeof(struct ieee80211_ie_htcap)-2,
scan->htcap = NULL);
}
if (scan->htinfo != NULL) {
IEEE80211_VERIFY_LENGTH(scan->htinfo[1],
scan->htinfo[0] == IEEE80211_ELEMID_VENDOR ?
4 + sizeof(struct ieee80211_ie_htinfo)-2 :
sizeof(struct ieee80211_ie_htinfo)-2,
scan->htinfo = NULL);
}
/* Process VHT IEs */
if (scan->vhtcap != NULL) {
IEEE80211_VERIFY_LENGTH(scan->vhtcap[1],
sizeof(struct ieee80211_ie_vhtcap) - 2,
scan->vhtcap = NULL);
}
if (scan->vhtopmode != NULL) {
IEEE80211_VERIFY_LENGTH(scan->vhtopmode[1],
sizeof(struct ieee80211_ie_vht_operation) - 2,
scan->vhtopmode = NULL);
}
return scan->status;
}
/*
* Parse an Action frame. Return 0 on success, non-zero on failure.
*/
int
ieee80211_parse_action(struct ieee80211_node *ni, struct mbuf *m)
{
struct ieee80211vap *vap = ni->ni_vap;
const struct ieee80211_action *ia;
struct ieee80211_frame *wh;
uint8_t *frm, *efrm;
/*
* action frame format:
* [1] category
* [1] action
* [tlv] parameters
*/
wh = mtod(m, struct ieee80211_frame *);
frm = (u_int8_t *)&wh[1];
efrm = mtod(m, u_int8_t *) + m->m_len;
IEEE80211_VERIFY_LENGTH(efrm - frm,
sizeof(struct ieee80211_action), return EINVAL);
ia = (const struct ieee80211_action *) frm;
vap->iv_stats.is_rx_action++;
IEEE80211_NODE_STAT(ni, rx_action);
/* verify frame payloads but defer processing */
switch (ia->ia_category) {
case IEEE80211_ACTION_CAT_BA:
switch (ia->ia_action) {
case IEEE80211_ACTION_BA_ADDBA_REQUEST:
IEEE80211_VERIFY_LENGTH(efrm - frm,
sizeof(struct ieee80211_action_ba_addbarequest),
return EINVAL);
break;
case IEEE80211_ACTION_BA_ADDBA_RESPONSE:
IEEE80211_VERIFY_LENGTH(efrm - frm,
sizeof(struct ieee80211_action_ba_addbaresponse),
return EINVAL);
break;
case IEEE80211_ACTION_BA_DELBA:
IEEE80211_VERIFY_LENGTH(efrm - frm,
sizeof(struct ieee80211_action_ba_delba),
return EINVAL);
break;
}
break;
case IEEE80211_ACTION_CAT_HT:
switch (ia->ia_action) {
case IEEE80211_ACTION_HT_TXCHWIDTH:
IEEE80211_VERIFY_LENGTH(efrm - frm,
sizeof(struct ieee80211_action_ht_txchwidth),
return EINVAL);
break;
case IEEE80211_ACTION_HT_MIMOPWRSAVE:
IEEE80211_VERIFY_LENGTH(efrm - frm,
sizeof(struct ieee80211_action_ht_mimopowersave),
return EINVAL);
break;
}
break;
#ifdef IEEE80211_SUPPORT_MESH
case IEEE80211_ACTION_CAT_MESH:
switch (ia->ia_action) {
case IEEE80211_ACTION_MESH_LMETRIC:
/*
* XXX: verification is true only if we are using
* Airtime link metric (default)
*/
IEEE80211_VERIFY_LENGTH(efrm - frm,
sizeof(struct ieee80211_meshlmetric_ie),
return EINVAL);
break;
case IEEE80211_ACTION_MESH_HWMP:
/* verify something */
break;
case IEEE80211_ACTION_MESH_GANN:
IEEE80211_VERIFY_LENGTH(efrm - frm,
sizeof(struct ieee80211_meshgann_ie),
return EINVAL);
break;
case IEEE80211_ACTION_MESH_CC:
case IEEE80211_ACTION_MESH_MCCA_SREQ:
case IEEE80211_ACTION_MESH_MCCA_SREP:
case IEEE80211_ACTION_MESH_MCCA_AREQ:
case IEEE80211_ACTION_MESH_MCCA_ADVER:
case IEEE80211_ACTION_MESH_MCCA_TRDOWN:
case IEEE80211_ACTION_MESH_TBTT_REQ:
case IEEE80211_ACTION_MESH_TBTT_RES:
/* reject these early on, not implemented */
IEEE80211_DISCARD(vap,
IEEE80211_MSG_ELEMID | IEEE80211_MSG_INPUT,
wh, NULL, "not implemented yet, act=0x%02X",
ia->ia_action);
return EINVAL;
}
break;
case IEEE80211_ACTION_CAT_SELF_PROT:
/* If TA or RA group address discard silently */
if (IEEE80211_IS_MULTICAST(wh->i_addr1) ||
IEEE80211_IS_MULTICAST(wh->i_addr2))
return EINVAL;
/*
* XXX: Should we verify complete length now or it is
* to varying in sizes?
*/
switch (ia->ia_action) {
case IEEE80211_ACTION_MESHPEERING_CONFIRM:
case IEEE80211_ACTION_MESHPEERING_CLOSE:
/* is not a peering candidate (yet) */
if (ni == vap->iv_bss)
return EINVAL;
break;
}
break;
#endif
case IEEE80211_ACTION_CAT_VHT:
printf("%s: TODO: VHT handling!\n", __func__);
break;
}
return 0;
}
#ifdef IEEE80211_DEBUG
/*
* Debugging support.
*/
void
ieee80211_ssid_mismatch(struct ieee80211vap *vap, const char *tag,
uint8_t mac[IEEE80211_ADDR_LEN], uint8_t *ssid)
{
printf("[%s] discard %s frame, ssid mismatch: ",
ether_sprintf(mac), tag);
ieee80211_print_essid(ssid + 2, ssid[1]);
printf("\n");
}
/*
* Return the bssid of a frame.
*/
static const uint8_t *
ieee80211_getbssid(const struct ieee80211vap *vap,
const struct ieee80211_frame *wh)
{
if (vap->iv_opmode == IEEE80211_M_STA)
return wh->i_addr2;
if ((wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) != IEEE80211_FC1_DIR_NODS)
return wh->i_addr1;
if ((wh->i_fc[0] & IEEE80211_FC0_SUBTYPE_MASK) == IEEE80211_FC0_SUBTYPE_PS_POLL)
return wh->i_addr1;
return wh->i_addr3;
}
#include <machine/stdarg.h>
void
ieee80211_note(const struct ieee80211vap *vap, const char *fmt, ...)
{
char buf[128]; /* XXX */
va_list ap;
va_start(ap, fmt);
vsnprintf(buf, sizeof(buf), fmt, ap);
va_end(ap);
if_printf(vap->iv_ifp, "%s", buf); /* NB: no \n */
}
void
ieee80211_note_frame(const struct ieee80211vap *vap,
const struct ieee80211_frame *wh,
const char *fmt, ...)
{
char buf[128]; /* XXX */
va_list ap;
va_start(ap, fmt);
vsnprintf(buf, sizeof(buf), fmt, ap);
va_end(ap);
if_printf(vap->iv_ifp, "[%s] %s\n",
ether_sprintf(ieee80211_getbssid(vap, wh)), buf);
}
void
ieee80211_note_mac(const struct ieee80211vap *vap,
const uint8_t mac[IEEE80211_ADDR_LEN],
const char *fmt, ...)
{
char buf[128]; /* XXX */
va_list ap;
va_start(ap, fmt);
vsnprintf(buf, sizeof(buf), fmt, ap);
va_end(ap);
if_printf(vap->iv_ifp, "[%s] %s\n", ether_sprintf(mac), buf);
}
void
ieee80211_discard_frame(const struct ieee80211vap *vap,
const struct ieee80211_frame *wh,
const char *type, const char *fmt, ...)
{
va_list ap;
if_printf(vap->iv_ifp, "[%s] discard ",
ether_sprintf(ieee80211_getbssid(vap, wh)));
printf("%s frame, ", type != NULL ? type :
ieee80211_mgt_subtype_name(wh->i_fc[0]));
va_start(ap, fmt);
vprintf(fmt, ap);
va_end(ap);
printf("\n");
}
void
ieee80211_discard_ie(const struct ieee80211vap *vap,
const struct ieee80211_frame *wh,
const char *type, const char *fmt, ...)
{
va_list ap;
if_printf(vap->iv_ifp, "[%s] discard ",
ether_sprintf(ieee80211_getbssid(vap, wh)));
if (type != NULL)
printf("%s information element, ", type);
else
printf("information element, ");
va_start(ap, fmt);
vprintf(fmt, ap);
va_end(ap);
printf("\n");
}
void
ieee80211_discard_mac(const struct ieee80211vap *vap,
const uint8_t mac[IEEE80211_ADDR_LEN],
const char *type, const char *fmt, ...)
{
va_list ap;
if_printf(vap->iv_ifp, "[%s] discard ", ether_sprintf(mac));
if (type != NULL)
printf("%s frame, ", type);
else
printf("frame, ");
va_start(ap, fmt);
vprintf(fmt, ap);
va_end(ap);
printf("\n");
}
#endif /* IEEE80211_DEBUG */
Reference in New Issue View Git Blame Copy Permalink