From 96fc6efb9ad9d0cd8cbb4462f0eb2a07092649e6 Mon Sep 17 00:00:00 2001 From: Alexander Wetzel Date: Tue, 19 Mar 2019 21:34:08 +0100 Subject: mac80211: IEEE 802.11 Extended Key ID support Add support for Extended Key ID as defined in IEEE 802.11-2016. - Implement the nl80211 API for Extended Key ID - Extend mac80211 API to allow drivers to support Extended Key ID - Enable Extended Key ID by default for drivers only supporting SW crypto (e.g. mac80211_hwsim) - Allow unicast Tx usage to be supressed (IEEE80211_KEY_FLAG_NO_AUTO_TX) - Select the decryption key based on the MPDU keyid - Enforce existing assumptions in the code that rekeys don't change the cipher Signed-off-by: Alexander Wetzel [remove module parameter] Signed-off-by: Johannes Berg --- net/mac80211/rx.c | 74 +++++++++++++++++++++++++++++-------------------------- 1 file changed, 39 insertions(+), 35 deletions(-) (limited to 'net/mac80211/rx.c') diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index 7f8d93401ce0..4a03c18b39a8 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -1005,23 +1005,43 @@ static int ieee80211_get_mmie_keyidx(struct sk_buff *skb) return -1; } -static int ieee80211_get_cs_keyid(const struct ieee80211_cipher_scheme *cs, - struct sk_buff *skb) +static int ieee80211_get_keyid(struct sk_buff *skb, + const struct ieee80211_cipher_scheme *cs) { struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; __le16 fc; int hdrlen; + int minlen; + u8 key_idx_off; + u8 key_idx_shift; u8 keyid; fc = hdr->frame_control; hdrlen = ieee80211_hdrlen(fc); - if (skb->len < hdrlen + cs->hdr_len) + if (cs) { + minlen = hdrlen + cs->hdr_len; + key_idx_off = hdrlen + cs->key_idx_off; + key_idx_shift = cs->key_idx_shift; + } else { + /* WEP, TKIP, CCMP and GCMP */ + minlen = hdrlen + IEEE80211_WEP_IV_LEN; + key_idx_off = hdrlen + 3; + key_idx_shift = 6; + } + + if (unlikely(skb->len < minlen)) return -EINVAL; - skb_copy_bits(skb, hdrlen + cs->key_idx_off, &keyid, 1); - keyid &= cs->key_idx_mask; - keyid >>= cs->key_idx_shift; + skb_copy_bits(skb, key_idx_off, &keyid, 1); + + if (cs) + keyid &= cs->key_idx_mask; + keyid >>= key_idx_shift; + + /* cs could use more than the usual two bits for the keyid */ + if (unlikely(keyid >= NUM_DEFAULT_KEYS)) + return -EINVAL; return keyid; } @@ -1852,9 +1872,9 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx) struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb); struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data; int keyidx; - int hdrlen; ieee80211_rx_result result = RX_DROP_UNUSABLE; struct ieee80211_key *sta_ptk = NULL; + struct ieee80211_key *ptk_idx = NULL; int mmie_keyidx = -1; __le16 fc; const struct ieee80211_cipher_scheme *cs = NULL; @@ -1892,21 +1912,24 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx) if (rx->sta) { int keyid = rx->sta->ptk_idx; + sta_ptk = rcu_dereference(rx->sta->ptk[keyid]); - if (ieee80211_has_protected(fc) && rx->sta->cipher_scheme) { + if (ieee80211_has_protected(fc)) { cs = rx->sta->cipher_scheme; - keyid = ieee80211_get_cs_keyid(cs, rx->skb); + keyid = ieee80211_get_keyid(rx->skb, cs); + if (unlikely(keyid < 0)) return RX_DROP_UNUSABLE; + + ptk_idx = rcu_dereference(rx->sta->ptk[keyid]); } - sta_ptk = rcu_dereference(rx->sta->ptk[keyid]); } if (!ieee80211_has_protected(fc)) mmie_keyidx = ieee80211_get_mmie_keyidx(rx->skb); if (!is_multicast_ether_addr(hdr->addr1) && sta_ptk) { - rx->key = sta_ptk; + rx->key = ptk_idx ? ptk_idx : sta_ptk; if ((status->flag & RX_FLAG_DECRYPTED) && (status->flag & RX_FLAG_IV_STRIPPED)) return RX_CONTINUE; @@ -1966,8 +1989,6 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx) } return RX_CONTINUE; } else { - u8 keyid; - /* * The device doesn't give us the IV so we won't be * able to look up the key. That's ok though, we @@ -1981,23 +2002,10 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx) (status->flag & RX_FLAG_IV_STRIPPED)) return RX_CONTINUE; - hdrlen = ieee80211_hdrlen(fc); - - if (cs) { - keyidx = ieee80211_get_cs_keyid(cs, rx->skb); + keyidx = ieee80211_get_keyid(rx->skb, cs); - if (unlikely(keyidx < 0)) - return RX_DROP_UNUSABLE; - } else { - if (rx->skb->len < 8 + hdrlen) - return RX_DROP_UNUSABLE; /* TODO: count this? */ - /* - * no need to call ieee80211_wep_get_keyidx, - * it verifies a bunch of things we've done already - */ - skb_copy_bits(rx->skb, hdrlen + 3, &keyid, 1); - keyidx = keyid >> 6; - } + if (unlikely(keyidx < 0)) + return RX_DROP_UNUSABLE; /* check per-station GTK first, if multicast packet */ if (is_multicast_ether_addr(hdr->addr1) && rx->sta) @@ -4042,12 +4050,8 @@ void ieee80211_check_fast_rx(struct sta_info *sta) case WLAN_CIPHER_SUITE_GCMP_256: break; default: - /* we also don't want to deal with WEP or cipher scheme - * since those require looking up the key idx in the - * frame, rather than assuming the PTK is used - * (we need to revisit this once we implement the real - * PTK index, which is now valid in the spec, but we - * haven't implemented that part yet) + /* We also don't want to deal with + * WEP or cipher scheme. */ goto clear_rcu; } -- cgit v1.2.3