mac80211: check defrag PN against current frame

commit bf30ca922a upstream.

As pointed out by Mathy Vanhoef, we implement the RX PN check
on fragmented frames incorrectly - we check against the last
received PN prior to the new frame, rather than to the one in
this frame itself.

Prior patches addressed the security issue here, but in order
to be able to reason better about the code, fix it to really
compare against the current frame's PN, not the last stored
one.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210511200110.bfbc340ff071.Id0b690e581da7d03d76df90bb0e3fd55930bc8a0@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johannes Berg 2021-05-31 22:31:32 +02:00 committed by Greg Kroah-Hartman
parent df3ca9d4ed
commit a9b57952fe
3 changed files with 19 additions and 9 deletions

View file

@ -223,8 +223,15 @@ struct ieee80211_rx_data {
*/
int security_idx;
u32 tkip_iv32;
u16 tkip_iv16;
union {
struct {
u32 iv32;
u16 iv16;
} tkip;
struct {
u8 pn[IEEE80211_CCMP_PN_LEN];
} ccm_gcm;
};
};
struct ieee80211_csa_settings {

View file

@ -2082,7 +2082,6 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
if (entry->check_sequential_pn) {
int i;
u8 pn[IEEE80211_CCMP_PN_LEN], *rpn;
int queue;
if (!requires_sequential_pn(rx, fc))
return RX_DROP_UNUSABLE;
@ -2097,8 +2096,8 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
if (pn[i])
break;
}
queue = rx->security_idx;
rpn = rx->key->u.ccmp.rx_pn[queue];
rpn = rx->ccm_gcm.pn;
if (memcmp(pn, rpn, IEEE80211_CCMP_PN_LEN))
return RX_DROP_UNUSABLE;
memcpy(entry->last_pn, pn, IEEE80211_CCMP_PN_LEN);

View file

@ -162,8 +162,8 @@ ieee80211_rx_h_michael_mic_verify(struct ieee80211_rx_data *rx)
update_iv:
/* update IV in key information to be able to detect replays */
rx->key->u.tkip.rx[rx->security_idx].iv32 = rx->tkip_iv32;
rx->key->u.tkip.rx[rx->security_idx].iv16 = rx->tkip_iv16;
rx->key->u.tkip.rx[rx->security_idx].iv32 = rx->tkip.iv32;
rx->key->u.tkip.rx[rx->security_idx].iv16 = rx->tkip.iv16;
return RX_CONTINUE;
@ -289,8 +289,8 @@ ieee80211_crypto_tkip_decrypt(struct ieee80211_rx_data *rx)
key, skb->data + hdrlen,
skb->len - hdrlen, rx->sta->sta.addr,
hdr->addr1, hwaccel, rx->security_idx,
&rx->tkip_iv32,
&rx->tkip_iv16);
&rx->tkip.iv32,
&rx->tkip.iv16);
if (res != TKIP_DECRYPT_OK)
return RX_DROP_UNUSABLE;
@ -548,6 +548,8 @@ ieee80211_crypto_ccmp_decrypt(struct ieee80211_rx_data *rx,
}
memcpy(key->u.ccmp.rx_pn[queue], pn, IEEE80211_CCMP_PN_LEN);
if (unlikely(ieee80211_is_frag(hdr)))
memcpy(rx->ccm_gcm.pn, pn, IEEE80211_CCMP_PN_LEN);
}
/* Remove CCMP header and MIC */
@ -777,6 +779,8 @@ ieee80211_crypto_gcmp_decrypt(struct ieee80211_rx_data *rx)
}
memcpy(key->u.gcmp.rx_pn[queue], pn, IEEE80211_GCMP_PN_LEN);
if (unlikely(ieee80211_is_frag(hdr)))
memcpy(rx->ccm_gcm.pn, pn, IEEE80211_CCMP_PN_LEN);
}
/* Remove GCMP header and MIC */