diff options
| author |   Mathy Vanhoef <Mathy.Vanhoef@kuleuven.be> | 2021-05-11 20:02:43 +0200 |
|---|---|---|
| committer |   Johannes Berg <johannes.berg@intel.com> | 2021-05-11 20:12:51 +0200 |
| commit | 94034c40ab4a3fcf581fbc7f8fdf4e29943c4a24 (patch) | |
| tree | a6319a8f6aa0c1c11131b86e5328cb4b7b0d54fd /net/mac80211/rx.c | |
| parent | mac80211: assure all fragments are encrypted (diff) | |
| download | linux-dev-94034c40ab4a3fcf581fbc7f8fdf4e29943c4a24.tar.xz linux-dev-94034c40ab4a3fcf581fbc7f8fdf4e29943c4a24.zip | |
mac80211: prevent mixed key and fragment cache attacks
Simultaneously prevent mixed key attacks (CVE-2020-24587) and fragment
cache attacks (CVE-2020-24586). This is accomplished by assigning a
unique color to every key (per interface) and using this to track which
key was used to decrypt a fragment. When reassembling frames, it is
now checked whether all fragments were decrypted using the same key.
To assure that fragment cache attacks are also prevented, the ID that is
assigned to keys is unique even over (re)associations and (re)connects.
This means fragments separated by a (re)association or (re)connect will
not be reassembled. Because mac80211 now also prevents the reassembly of
mixed encrypted and plaintext fragments, all cache attacks are prevented.
Cc: stable@vger.kernel.org
Signed-off-by: Mathy Vanhoef <Mathy.Vanhoef@kuleuven.be>
Link: https://lore.kernel.org/r/20210511200110.3f8290e59823.I622a67769ed39257327a362cfc09c812320eb979@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/mac80211/rx.c')
| -rw-r--r-- | net/mac80211/rx.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index 65fc674e27cc..531232b91bc4 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -2255,6 +2255,7 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) * next fragment has a sequential PN value. */ entry->check_sequential_pn = true; + entry->key_color = rx->key->color; memcpy(entry->last_pn, rx->key->u.ccmp.rx_pn[queue], IEEE80211_CCMP_PN_LEN); @@ -2292,6 +2293,11 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx) if (!requires_sequential_pn(rx, fc)) return RX_DROP_UNUSABLE; + + /* Prevent mixed key and fragment cache attacks */ + if (entry->key_color != rx->key->color) + return RX_DROP_UNUSABLE; + memcpy(pn, entry->last_pn, IEEE80211_CCMP_PN_LEN); for (i = IEEE80211_CCMP_PN_LEN - 1; i >= 0; i--) { pn[i]++; |