[PATCH] net: wireless: intel: iwlwifi: dvm: fix tid mask

Currently the tid mask covers the first 4 bits of iwlagn_tx_resp::ra_tid,
which gives 16 possible values for tid.
This is problematic because IWL_MAX_TID_COUNT is 8, so indexing
iwl_priv::tid_data can go very wrong.

With UBSAN I can it happening while establishing the first connection
after module load.

[  272.143440] UBSAN: Undefined behaviour in drivers/net/wireless/intel/iwlwifi/dvm/tx.c:777:32
[  272.143447] index 8 is out of range for type 'iwl_tid_data [8]'
[  272.143457] CPU: 0 PID: 4605 Comm: irq/32-iwlwifi Not tainted 4.12.0-dirty #2
[  272.143460] Hardware name: Hewlett-Packard HP EliteBook 2560p/162B, BIOS 68SSU Ver. F.02 07/26/2011
[  272.143462] Call Trace:
[  272.143472]  dump_stack+0x9c/0x10b
[  272.143477]  ? _atomic_dec_and_lock+0x285/0x285
[  272.143486]  ubsan_epilogue+0xd/0x4e
[  272.143493]  __ubsan_handle_out_of_bounds+0xef/0x118
[  272.143498]  ? __ubsan_handle_shift_out_of_bounds+0x221/0x221
[  272.143519]  ? iwl_trans_pcie_reclaim+0x153/0xc90 [iwlwifi]
[  272.143539]  iwlagn_check_ratid_empty+0x337/0x410 [iwldvm]
[  272.143556]  ? iwl_hcmd_names_cmp+0x2f/0x60 [iwlwifi]
[  272.143571]  iwlagn_rx_reply_tx+0x8a4/0x1820 [iwldvm]

Signed-off-by: Seraphime Kirkovski <redacted>
---
   I'm currently running this patch on my machines and I have wifi.
   The patch presumes а cleanup patch, I sent yesterday:
      https://www.spinics.net/lists/kernel/msg2526314.html

 drivers/net/wireless/intel/iwlwifi/dvm/commands.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/dvm/commands.h b/drivers/net/wireless/intel/iwlwifi/dvm/commands.h
index 37d2ba5ae852..e5994df9ea4c 100644
--- a/drivers/net/wireless/intel/iwlwifi/dvm/commands.h
+++ b/drivers/net/wireless/intel/iwlwifi/dvm/commands.h

@@ -1448,7 +1448,7 @@ struct agg_tx_status {
  */
 /* refer to ra_tid */
 #define IWLAGN_TX_RES_TID_POS	0
-#define IWLAGN_TX_RES_TID_MSK	0x0f
+#define IWLAGN_TX_RES_TID_MSK	0x07
 #define IWLAGN_TX_RES_RA_POS	4
 #define IWLAGN_TX_RES_RA_MSK	0xf0
 

-- 
2.11.0

Hi,

Subject: [linuxwifi] [PATCH] net: wireless: intel: iwlwifi: dvm: fix tid mask

Currently the tid mask covers the first 4 bits of iwlagn_tx_resp::ra_tid,
which gives 16 possible values for tid.
This is problematic because IWL_MAX_TID_COUNT is 8, so indexing
iwl_priv::tid_data can go very wrong.

True, OTOH we need tid to be 8 sometimes. We *just* need to make sure
that we don't index tid_data with this. Hence I think the proper fix is:

diff --git a/drivers/net/wireless/intel/iwlwifi/dvm/tx.c b/drivers/net/wireless/intel/iwlwifi/dvm/tx.c
index 06ac3f1..16a8646 100644
--- a/drivers/net/wireless/intel/iwlwifi/dvm/tx.c
+++ b/drivers/net/wireless/intel/iwlwifi/dvm/tx.c

@@ -1190,11 +1190,11 @@ void iwlagn_rx_reply_tx(struct iwl_priv *priv, struct iwl_rx_cmd_buffer *rxb)
                                next_reclaimed;
                        IWL_DEBUG_TX_REPLY(priv, "Next reclaimed packet:%d\n",
                                                  next_reclaimed);
+                       iwlagn_check_ratid_empty(priv, sta_id, tid);
                }

                iwl_trans_reclaim(priv->trans, txq_id, ssn, &skbs);

-               iwlagn_check_ratid_empty(priv, sta_id, tid);
                freed = 0;

                /* process frames */

Clearly calling iwlagn_check_ratid_empty with tid = IWL_TID_NON_QOS is a bad idea.

On Thu, Jun 08, 2017 at 06:31:01AM +0000, Grumbach, Emmanuel wrote:

Hi,

Hi,

I can confirm it works. You can add my Tested-By.

Thanks,
Seraph

On Thu, Jun 08, 2017 at 06:31:01AM +0000, Grumbach, Emmanuel wrote:

quoted

Hi,

Hi,

quoted

True, OTOH we need tid to be 8 sometimes. We *just* need to make sure
that we don't index tid_data with this. Hence I think the proper fix is:

diff --git a/drivers/net/wireless/intel/iwlwifi/dvm/tx.c

b/drivers/net/wireless/intel/iwlwifi/dvm/tx.c
index 06ac3f1..16a8646 100644

--- a/drivers/net/wireless/intel/iwlwifi/dvm/tx.c
+++ b/drivers/net/wireless/intel/iwlwifi/dvm/tx.c

@@ -1190,11 +1190,11 @@ void iwlagn_rx_reply_tx(struct iwl_priv *priv,

struct iwl_rx_cmd_buffer *rxb)

quoted

                                next_reclaimed;
                        IWL_DEBUG_TX_REPLY(priv, "Next reclaimed packet:%d\n",
                                                  next_reclaimed);
+                       iwlagn_check_ratid_empty(priv, sta_id, tid);
                }

                iwl_trans_reclaim(priv->trans, txq_id, ssn, &skbs);

-               iwlagn_check_ratid_empty(priv, sta_id, tid);
                freed = 0;

                /* process frames */

I can confirm it works. You can add my Tested-By.

Patch in review in our internal tree. It'll be upstreamed through the regular process.
Thanks for your report and debug work.