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    Subject[PATCH 4.19 018/116] mac80211: prevent attacks on TKIP/WEP as well
    Date
    From: Johannes Berg <johannes.berg@intel.com>

    commit 7e44a0b597f04e67eee8cdcbe7ee706c6f5de38b upstream.

    Similar to the issues fixed in previous patches, TKIP and WEP
    should be protected even if for TKIP we have the Michael MIC
    protecting it, and WEP is broken anyway.

    However, this also somewhat protects potential other algorithms
    that drivers might implement.

    Cc: stable@vger.kernel.org
    Link: https://lore.kernel.org/r/20210511200110.430e8c202313.Ia37e4e5b6b3eaab1a5ae050e015f6c92859dbe27@changeid
    Signed-off-by: Johannes Berg <johannes.berg@intel.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    net/mac80211/rx.c | 12 ++++++++++++
    net/mac80211/sta_info.h | 3 ++-
    2 files changed, 14 insertions(+), 1 deletion(-)

    --- a/net/mac80211/rx.c
    +++ b/net/mac80211/rx.c
    @@ -2158,6 +2158,7 @@ ieee80211_rx_h_defragment(struct ieee802
    * next fragment has a sequential PN value.
    */
    entry->check_sequential_pn = true;
    + entry->is_protected = true;
    entry->key_color = rx->key->color;
    memcpy(entry->last_pn,
    rx->key->u.ccmp.rx_pn[queue],
    @@ -2170,6 +2171,9 @@ ieee80211_rx_h_defragment(struct ieee802
    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)) {
    + entry->is_protected = true;
    + entry->key_color = rx->key->color;
    }
    return RX_QUEUED;
    }
    @@ -2211,6 +2215,14 @@ ieee80211_rx_h_defragment(struct ieee802
    if (memcmp(pn, rpn, IEEE80211_CCMP_PN_LEN))
    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->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;
    }

    skb_pull(rx->skb, ieee80211_hdrlen(fc));
    --- a/net/mac80211/sta_info.h
    +++ b/net/mac80211/sta_info.h
    @@ -429,7 +429,8 @@ struct ieee80211_fragment_entry {
    u16 extra_len;
    u16 last_frag;
    u8 rx_queue;
    - bool check_sequential_pn; /* needed for CCMP/GCMP */
    + u8 check_sequential_pn:1, /* needed for CCMP/GCMP */
    + is_protected:1;
    u8 last_pn[6]; /* PN of the last fragment if CCMP was used */
    unsigned int key_color;
    };

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