[Add Peter in Cc:]
On Thursday 15 September 2022 15:14:45 CEST Lech Perczak wrote:
> From: Paweł Lenkow <pawel.lenkow@xxxxxxxxxxxxxxx>
>
> During our testing of WFM200 module over SDIO on i.MX6Q-based platform,
> we discovered a memory corruption on the system, tracing back to the wfx
> driver. Using kfence, it was possible to trace it back to the root
> cause, which is hw->max_rates set to 8 in wfx_init_common,
> while the maximum defined by IEEE80211_TX_TABLE_SIZE is 4.
>
> This causes array out-of-bounds writes during updates of the rate table,
> as seen below:
>
> BUG: KFENCE: memory corruption in kfree_rcu_work+0x320/0x36c
>
> Corrupted memory at 0xe0a4ffe0 [ 0x03 0x03 0x03 0x03 0x01 0x00 0x00
> 0x02 0x02 0x02 0x09 0x00 0x21 0xbb 0xbb 0xbb ] (in kfence-#81):
> kfree_rcu_work+0x320/0x36c
> process_one_work+0x3ec/0x920
> worker_thread+0x60/0x7a4
> kthread+0x174/0x1b4
> ret_from_fork+0x14/0x2c
> 0x0
>
> kfence-#81: 0xe0a4ffc0-0xe0a4ffdf, size=32, cache=kmalloc-64
>
> allocated by task 297 on cpu 0 at 631.039555s:
> minstrel_ht_update_rates+0x38/0x2b0 [mac80211]
> rate_control_tx_status+0xb4/0x148 [mac80211]
> ieee80211_tx_status_ext+0x364/0x1030 [mac80211]
> ieee80211_tx_status+0xe0/0x118 [mac80211]
> ieee80211_tasklet_handler+0xb0/0xe0 [mac80211]
> tasklet_action_common.constprop.0+0x11c/0x148
> __do_softirq+0x1a4/0x61c
> irq_exit+0xcc/0x104
> call_with_stack+0x18/0x20
> __irq_svc+0x80/0xb0
> wq_worker_sleeping+0x10/0x100
> wq_worker_sleeping+0x10/0x100
> schedule+0x50/0xe0
> schedule_timeout+0x2e0/0x474
> wait_for_completion+0xdc/0x1ec
> mmc_wait_for_req_done+0xc4/0xf8
> mmc_io_rw_extended+0x3b4/0x4ec
> sdio_io_rw_ext_helper+0x290/0x384
> sdio_memcpy_toio+0x30/0x38
> wfx_sdio_copy_to_io+0x88/0x108 [wfx]
> wfx_data_write+0x88/0x1f0 [wfx]
> bh_work+0x1c8/0xcc0 [wfx]
> process_one_work+0x3ec/0x920
> worker_thread+0x60/0x7a4
> kthread+0x174/0x1b4
> ret_from_fork+0x14/0x2c 0x0
>
> Limit hw->max_rates to not exceed IEEE80211_TX_RATE_TABLE_SIZE (4).
>
> To bring back previous value, the global table size limit needs to be
> increased beforehand in mac80211.h, or by limiting the iteration count
> in minstrel_ht_update_rates against IEEE80211_TX_RATE_TABLE_SIZE as
> well.
>
> Fixes: e16e7f0716a6 ("staging: wfx: instantiate mac80211 data")
I think the issue has been introduced by ee0e16ab756a ("mac80211:
minstrel_ht: fill all requested rates").
> Cc: Jérôme Pouiller <jerome.pouiller@xxxxxxxxxx>
> Cc: Kalle Valo <kvalo@xxxxxxxxxx>
> Link: https://urldefense.com/v3/__https://lore.kernel.org/all/12e5adcd-8aed-f0f7-70cc-4fb7b656b829@xxxxxxxxxxxxxxx/__;!!N30Cs7Jr!ReVaYMRjWoJzG95KRgrZTGAw0bmt5lnLLpRkt574SRvIoKLD2xl53YKUiLpN4PfXpjSLIQ9KvgVy9Wi4jeJE8axP9M4Odgk$
>
> Signed-off-by: Paweł Lenkow <pawel.lenkow@xxxxxxxxxxxxxxx>
> Signed-off-by: Lech Perczak <lech.perczak@xxxxxxxxxxxxxxx>
> ---
> drivers/net/wireless/silabs/wfx/main.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/wireless/silabs/wfx/main.c b/drivers/net/wireless/silabs/wfx/main.c
> index 84d82ddded56..7463fe4b5cae 100644
> --- a/drivers/net/wireless/silabs/wfx/main.c
> +++ b/drivers/net/wireless/silabs/wfx/main.c
> @@ -273,7 +273,7 @@ struct wfx_dev *wfx_init_common(struct device *dev, const struct wfx_platform_da
> hw->vif_data_size = sizeof(struct wfx_vif);
> hw->sta_data_size = sizeof(struct wfx_sta_priv);
> hw->queues = 4;
> - hw->max_rates = 8;
> + hw->max_rates = 4;
> hw->max_rate_tries = 8;
> hw->extra_tx_headroom = sizeof(struct wfx_hif_msg) + sizeof(struct wfx_hif_req_tx) +
> 4 /* alignment */ + 8 /* TKIP IV */;
Do you think the fix should rather be:
------8<----------8<--------
--- i/net/mac80211/rc80211_minstrel_ht.c
+++ w/net/mac80211/rc80211_minstrel_ht.c
@@ -1559,7 +1559,7 @@ minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]);
/* Fill up remaining, keep one entry for max_probe_rate */
- for (; i < (mp->hw->max_rates - 1); i++)
+ for (; i < min(mp->hw->max_rates, IEEE80211_TX_RATE_TABLE_SIZE) - 1; i++)
minstrel_ht_set_rate(mp, mi, rates, i, mi->max_tp_rate[i]);
if (i < mp->hw->max_rates)
------8<----------8<--------
--
Jérôme Pouiller
