From: Wen Gong wgong@codeaurora.org
For some chips/drivers, e.g., QCA6174 with ath10k, the decryption is done by the hardware, and the Protected bit in the Frame Control field is cleared in the lower level driver before the frame is passed to mac80211. In such cases, the condition for ieee80211_has_protected() is not met in ieee80211_rx_h_defragment() of mac80211 and the new security validation steps are not executed.
Extend mac80211 to cover the case where the Protected bit has been cleared, but the frame is indicated as having been decrypted by the hardware. This extends protection against mixed key and fragment cache attack for additional drivers/chips. This fixes CVE-2020-24586 and CVE-2020-24587 for such cases.
Tested-on: QCA6174 hw3.2 PCI WLAN.RM.4.4.1-00110-QCARMSWP-1
Cc: stable@vger.kernel.org Signed-off-by: Wen Gong wgong@codeaurora.org Signed-off-by: Jouni Malinen jouni@codeaurora.org Signed-off-by: Johannes Berg johannes.berg@intel.com --- net/mac80211/rx.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index 22a925899a9e..1bb43edd47b6 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -2229,6 +2229,7 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) unsigned int frag, seq; struct ieee80211_fragment_entry *entry; struct sk_buff *skb; + struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
hdr = (struct ieee80211_hdr *)rx->skb->data; fc = hdr->frame_control; @@ -2287,7 +2288,9 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) sizeof(rx->key->u.gcmp.rx_pn[queue])); BUILD_BUG_ON(IEEE80211_CCMP_PN_LEN != IEEE80211_GCMP_PN_LEN); - } else if (rx->key && ieee80211_has_protected(fc)) { + } else if (rx->key && + (ieee80211_has_protected(fc) || + (status->flag & RX_FLAG_DECRYPTED))) { entry->is_protected = true; entry->key_color = rx->key->color; } @@ -2332,13 +2335,19 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) return RX_DROP_UNUSABLE; memcpy(entry->last_pn, pn, IEEE80211_CCMP_PN_LEN); } else if (entry->is_protected && - (!rx->key || !ieee80211_has_protected(fc) || + (!rx->key || + (!ieee80211_has_protected(fc) && + !(status->flag & RX_FLAG_DECRYPTED)) || rx->key->color != entry->key_color)) { /* Drop this as a mixed key or fragment cache attack, even * if for TKIP Michael MIC should protect us, and WEP is a * lost cause anyway. */ return RX_DROP_UNUSABLE; + } else if (entry->is_protected && rx->key && + entry->key_color != rx->key->color && + (status->flag & RX_FLAG_DECRYPTED)) { + return RX_DROP_UNUSABLE; }
skb_pull(rx->skb, ieee80211_hdrlen(fc));