git.openwrt.org Git - openwrt/staging/ldir.git/blob

   1 From: Sriram R <srirrama@codeaurora.org>
   2 Date: Tue, 11 May 2021 20:02:57 +0200
   3 Subject: [PATCH] ath10k: Validate first subframe of A-MSDU before
   4  processing the list
   5
   6 In certain scenarios a normal MSDU can be received as an A-MSDU when
   7 the A-MSDU present bit of a QoS header gets flipped during reception.
   8 Since this bit is unauthenticated, the hardware crypto engine can pass
   9 the frame to the driver without any error indication.
  10
  11 This could result in processing unintended subframes collected in the
  12 A-MSDU list. Hence, validate A-MSDU list by checking if the first frame
  13 has a valid subframe header.
  14
  15 Comparing the non-aggregated MSDU and an A-MSDU, the fields of the first
  16 subframe DA matches the LLC/SNAP header fields of a normal MSDU.
  17 In order to avoid processing such frames, add a validation to
  18 filter such A-MSDU frames where the first subframe header DA matches
  19 with the LLC/SNAP header pattern.
  20
  21 Tested-on: QCA9984 hw1.0 PCI 10.4-3.10-00047
  22
  23 Cc: stable@vger.kernel.org
  24 Signed-off-by: Sriram R <srirrama@codeaurora.org>
  25 Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
  26 Signed-off-by: Johannes Berg <johannes.berg@intel.com>
  27 ---
  28
  29 --- a/drivers/net/wireless/ath/ath10k/htt_rx.c
  30 +++ b/drivers/net/wireless/ath/ath10k/htt_rx.c
  31 @@ -2108,14 +2108,62 @@ static void ath10k_htt_rx_h_unchain(stru
  32         ath10k_unchain_msdu(amsdu, unchain_cnt);
  33  }
  34
  35 +static bool ath10k_htt_rx_validate_amsdu(struct ath10k *ar,
  36 +                                        struct sk_buff_head *amsdu)
  37 +{
  38 +       u8 *subframe_hdr;
  39 +       struct sk_buff *first;
  40 +       bool is_first, is_last;
  41 +       struct htt_rx_desc *rxd;
  42 +       struct ieee80211_hdr *hdr;
  43 +       size_t hdr_len, crypto_len;
  44 +       enum htt_rx_mpdu_encrypt_type enctype;
  45 +       int bytes_aligned = ar->hw_params.decap_align_bytes;
  46 +
  47 +       first = skb_peek(amsdu);
  48 +
  49 +       rxd = (void *)first->data - sizeof(*rxd);
  50 +       hdr = (void *)rxd->rx_hdr_status;
  51 +
  52 +       is_first = !!(rxd->msdu_end.common.info0 &
  53 +                     __cpu_to_le32(RX_MSDU_END_INFO0_FIRST_MSDU));
  54 +       is_last = !!(rxd->msdu_end.common.info0 &
  55 +                    __cpu_to_le32(RX_MSDU_END_INFO0_LAST_MSDU));
  56 +
  57 +       /* Return in case of non-aggregated msdu */
  58 +       if (is_first && is_last)
  59 +               return true;
  60 +
  61 +       /* First msdu flag is not set for the first msdu of the list */
  62 +       if (!is_first)
  63 +               return false;
  64 +
  65 +       enctype = MS(__le32_to_cpu(rxd->mpdu_start.info0),
  66 +                    RX_MPDU_START_INFO0_ENCRYPT_TYPE);
  67 +
  68 +       hdr_len = ieee80211_hdrlen(hdr->frame_control);
  69 +       crypto_len = ath10k_htt_rx_crypto_param_len(ar, enctype);
  70 +
  71 +       subframe_hdr = (u8 *)hdr + round_up(hdr_len, bytes_aligned) +
  72 +                      crypto_len;
  73 +
  74 +       /* Validate if the amsdu has a proper first subframe.
  75 +        * There are chances a single msdu can be received as amsdu when
  76 +        * the unauthenticated amsdu flag of a QoS header
  77 +        * gets flipped in non-SPP AMSDU's, in such cases the first
  78 +        * subframe has llc/snap header in place of a valid da.
  79 +        * return false if the da matches rfc1042 pattern
  80 +        */
  81 +       if (ether_addr_equal(subframe_hdr, rfc1042_header))
  82 +               return false;
  83 +
  84 +       return true;
  85 +}
  86 +
  87  static bool ath10k_htt_rx_amsdu_allowed(struct ath10k *ar,
  88                                         struct sk_buff_head *amsdu,
  89                                         struct ieee80211_rx_status *rx_status)
  90  {
  91 -       /* FIXME: It might be a good idea to do some fuzzy-testing to drop
  92 -        * invalid/dangerous frames.
  93 -        */
  94 -
  95         if (!rx_status->freq) {
  96                 ath10k_dbg(ar, ATH10K_DBG_HTT, "no channel configured; ignoring frame(s)!\n");
  97                 return false;
  98 @@ -2126,6 +2174,11 @@ static bool ath10k_htt_rx_amsdu_allowed(
  99                 return false;
 100         }
 101
 102 +       if (!ath10k_htt_rx_validate_amsdu(ar, amsdu)) {
 103 +               ath10k_dbg(ar, ATH10K_DBG_HTT, "invalid amsdu received\n");
 104 +               return false;
 105 +       }
 106 +
 107         return true;
 108  }
 109