package/kernel/mac80211/patches/rt2x00/013-rt2x00-Work-around-a-firmware-bug-with-shared-keys.patch

   1 From a4296994eb8061ee3455721a296c387c639bf635 Mon Sep 17 00:00:00 2001
   2 From: Bernd Edlinger <bernd.edlinger@hotmail.de>
   3 Date: Tue, 15 Jan 2019 14:01:29 +0000
   4 Subject: [PATCH 13/28] rt2x00: Work around a firmware bug with shared keys
   5
   6 Apparently the rt2x61 firmware fails temporarily to decode
   7 broadcast packets if the shared keys are not assigned
   8 in the "correct" sequence. At the same time unicast
   9 packets work fine, since they are encrypted with the
  10 pairwise key.
  11
  12 At least with WPA2 CCMP mode the shared keys are
  13 set in the following sequence: keyidx=1, 2, 1, 2.
  14 After a while only keyidx 2 gets decrypted, and
  15 keyidx 1 is ignored, probably because there is never
  16 a keyidx 3.
  17
  18 Symptoms are arping -b works for 10 minutes, since
  19 keyidx=2 is used for broadcast, and then it stops
  20 working for 10 minutes, because keyidx=1 is used.
  21 That failure mode repeats forever.
  22
  23 Note, the firmware does not even know which keyidx
  24 corresponds to which hw_key_idx so the firmware is
  25 trying to be smarter than the driver, which is bound
  26 to fail.
  27
  28 As workaround the function rt61pci_config_shared_key
  29 requests software decryption of the shared keys,
  30 by returning EOPNOTSUPP. However, pairwise keys are
  31 still handled by hardware which works just fine.
  32
  33 Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
  34 Acked-by: Stanislaw Gruszka <sgruszka@redhat.com>
  35 Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
  36 ---
  37  drivers/net/wireless/ralink/rt2x00/rt61pci.c | 93 +-------------------
  38  1 file changed, 4 insertions(+), 89 deletions(-)
  39
  40 --- a/drivers/net/wireless/ralink/rt2x00/rt61pci.c
  41 +++ b/drivers/net/wireless/ralink/rt2x00/rt61pci.c
  42 @@ -321,97 +321,12 @@ static int rt61pci_config_shared_key(str
  43                                      struct rt2x00lib_crypto *crypto,
  44                                      struct ieee80211_key_conf *key)
  45  {
  46 -       struct hw_key_entry key_entry;
  47 -       struct rt2x00_field32 field;
  48 -       u32 mask;
  49 -       u32 reg;
  50 -
  51 -       if (crypto->cmd == SET_KEY) {
  52 -               /*
  53 -                * rt2x00lib can't determine the correct free
  54 -                * key_idx for shared keys. We have 1 register
  55 -                * with key valid bits. The goal is simple, read
  56 -                * the register, if that is full we have no slots
  57 -                * left.
  58 -                * Note that each BSS is allowed to have up to 4
  59 -                * shared keys, so put a mask over the allowed
  60 -                * entries.
  61 -                */
  62 -               mask = (0xf << crypto->bssidx);
  63 -
  64 -               reg = rt2x00mmio_register_read(rt2x00dev, SEC_CSR0);
  65 -               reg &= mask;
  66 -
  67 -               if (reg && reg == mask)
  68 -                       return -ENOSPC;
  69 -
  70 -               key->hw_key_idx += reg ? ffz(reg) : 0;
  71 -
  72 -               /*
  73 -                * Upload key to hardware
  74 -                */
  75 -               memcpy(key_entry.key, crypto->key,
  76 -                      sizeof(key_entry.key));
  77 -               memcpy(key_entry.tx_mic, crypto->tx_mic,
  78 -                      sizeof(key_entry.tx_mic));
  79 -               memcpy(key_entry.rx_mic, crypto->rx_mic,
  80 -                      sizeof(key_entry.rx_mic));
  81 -
  82 -               reg = SHARED_KEY_ENTRY(key->hw_key_idx);
  83 -               rt2x00mmio_register_multiwrite(rt2x00dev, reg,
  84 -                                              &key_entry, sizeof(key_entry));
  85 -
  86 -               /*
  87 -                * The cipher types are stored over 2 registers.
  88 -                * bssidx 0 and 1 keys are stored in SEC_CSR1 and
  89 -                * bssidx 1 and 2 keys are stored in SEC_CSR5.
  90 -                * Using the correct defines correctly will cause overhead,
  91 -                * so just calculate the correct offset.
  92 -                */
  93 -               if (key->hw_key_idx < 8) {
  94 -                       field.bit_offset = (3 * key->hw_key_idx);
  95 -                       field.bit_mask = 0x7 << field.bit_offset;
  96 -
  97 -                       reg = rt2x00mmio_register_read(rt2x00dev, SEC_CSR1);
  98 -                       rt2x00_set_field32(&reg, field, crypto->cipher);
  99 -                       rt2x00mmio_register_write(rt2x00dev, SEC_CSR1, reg);
 100 -               } else {
 101 -                       field.bit_offset = (3 * (key->hw_key_idx - 8));
 102 -                       field.bit_mask = 0x7 << field.bit_offset;
 103 -
 104 -                       reg = rt2x00mmio_register_read(rt2x00dev, SEC_CSR5);
 105 -                       rt2x00_set_field32(&reg, field, crypto->cipher);
 106 -                       rt2x00mmio_register_write(rt2x00dev, SEC_CSR5, reg);
 107 -               }
 108 -
 109 -               /*
 110 -                * The driver does not support the IV/EIV generation
 111 -                * in hardware. However it doesn't support the IV/EIV
 112 -                * inside the ieee80211 frame either, but requires it
 113 -                * to be provided separately for the descriptor.
 114 -                * rt2x00lib will cut the IV/EIV data out of all frames
 115 -                * given to us by mac80211, but we must tell mac80211
 116 -                * to generate the IV/EIV data.
 117 -                */
 118 -               key->flags |= IEEE80211_KEY_FLAG_GENERATE_IV;
 119 -       }
 120 -
 121         /*
 122 -        * SEC_CSR0 contains only single-bit fields to indicate
 123 -        * a particular key is valid. Because using the FIELD32()
 124 -        * defines directly will cause a lot of overhead, we use
 125 -        * a calculation to determine the correct bit directly.
 126 +        * Let the software handle the shared keys,
 127 +        * since the hardware decryption does not work reliably,
 128 +        * because the firmware does not know the key's keyidx.
 129          */
 130 -       mask = 1 << key->hw_key_idx;
 131 -
 132 -       reg = rt2x00mmio_register_read(rt2x00dev, SEC_CSR0);
 133 -       if (crypto->cmd == SET_KEY)
 134 -               reg |= mask;
 135 -       else if (crypto->cmd == DISABLE_KEY)
 136 -               reg &= ~mask;
 137 -       rt2x00mmio_register_write(rt2x00dev, SEC_CSR0, reg);
 138 -
 139 -       return 0;
 140 +       return -EOPNOTSUPP;
 141  }
 142
 143  static int rt61pci_config_pairwise_key(struct rt2x00_dev *rt2x00dev,