| Message ID | 20220915131445.30600-1-lech.perczak@camlingroup.com |
|---|---|
| State | New |
| Headers | show |
| Series | wifi: wfx: fix memory corruption by limiting max_rates to 4 | expand |
Hi! Thank you for your suggestions and comments. We have submitted new patch here: https://patchwork.kernel.org/project/linux-wireless/patch/20220919150135.90785-1-lech.perczak@camlingroup.com/ On 15.09.2022 20:21, Peter Seiderer wrote: > Hello *, > > On Thu, 15 Sep 2022 16:02:34 +0200, Lech Perczak <lech.perczak@camlingroup.com> wrote: > >> Hi Jérôme, >> >> Answers inline. >> [Add Krzysztof in Cc:] >> >> W dniu 15.09.2022 o 15:39, Jérôme Pouiller pisze: >>> [Add Peter in Cc:] >>> >>> On Thursday 15 September 2022 15:14:45 CEST Lech Perczak wrote: >>>> From: Paweł Lenkow <pawel.lenkow@camlingroup.com> >>>> >>>> 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"). > > Ups, sorry for creating a regression (and many thanks for investigation)... > >>> >>> >>>> Cc: Jérôme Pouiller <jerome.pouiller@silabs.com> >>>> Cc: Kalle Valo <kvalo@kernel.org> >>>> Link: https://urldefense.com/v3/__https://lore.kernel.org/all/12e5adcd-8aed-f0f7-70cc-4fb7b656b829@camlingroup.com/__;!!N30Cs7Jr!ReVaYMRjWoJzG95KRgrZTGAw0bmt5lnLLpRkt574SRvIoKLD2xl53YKUiLpN4PfXpjSLIQ9KvgVy9Wi4jeJE8axP9M4Odgk$<https://urldefense.com/v3/__https://lore.kernel.org/all/12e5adcd-8aed-f0f7-70cc-4fb7b656b829@camlingroup.com/__;!!N30Cs7Jr!ReVaYMRjWoJzG95KRgrZTGAw0bmt5lnLLpRkt574SRvIoKLD2xl53YKUiLpN4PfXpjSLIQ9KvgVy9Wi4jeJE8axP9M4Odgk$> <https://urldefense.com/v3/__https://lore.kernel.org/all/12e5adcd-8aed-f0f7-70cc-4fb7b656b829@camlingroup.com/__;!!N30Cs7Jr!ReVaYMRjWoJzG95KRgrZTGAw0bmt5lnLLpRkt574SRvIoKLD2xl53YKUiLpN4PfXpjSLIQ9KvgVy9Wi4jeJE8axP9M4Odgk$<https://urldefense.com/v3/__https://lore.kernel.org/all/12e5adcd-8aed-f0f7-70cc-4fb7b656b829@camlingroup.com/__;!!N30Cs7Jr!ReVaYMRjWoJzG95KRgrZTGAw0bmt5lnLLpRkt574SRvIoKLD2xl53YKUiLpN4PfXpjSLIQ9KvgVy9Wi4jeJE8axP9M4Odgk$>> >>>> >>>> Signed-off-by: Paweł Lenkow <pawel.lenkow@camlingroup.com> >>>> Signed-off-by: Lech Perczak <lech.perczak@camlingroup.com> >>>> --- >>>> 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; > > Quick grep for max_rates did show the same for: > > drivers/net/wireless/st/cw1200/main.c: hw->max_rates = 8; > >>>> 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 */; >>> > > Think the following suggested fix is the right way to go (and keep hw->max_rates > value according to the hardware capabilities(?) of the wifi device)... > >>> 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]); >>> > > Same change needed here: > >>> if (i < mp->hw->max_rates) > > if (i < min(mp->hw->max_rates, IEEE80211_TX_RATE_TABLE_SIZE)) > >>> ------8<----------8<-------- >>> >> We thought about this as well - or about adding assertion to the function which does the memory allocation, >> but there are more 4-element arrays in mac80211, handled under different defines, which can be confusing. >> >> carl9170 driver has BUILD_BUG_ON to guard from that precisely - see: >> https://elixir.bootlin.com/linux/latest/source/drivers/net/wireless/ath/carl9170/tx.c#L879<https://elixir.bootlin.com/linux/latest/source/drivers/net/wireless/ath/carl9170/tx.c#L879> >> I think, that the second BUILD_BUG_ON could be moved to mac80211 core, so that it is checked always, >> not only when CARL9170 is enabled. >> >> I think both changes should be applied - or, alternatively, in minstrel_ht_set_rate, we could use: >> BUG_ON(mp->hw->max_rates > IEEE80211_TX_RATE_TABLE_SIZE); >> to quickly catch misbehaving drivers in future. > > Think with the suggested changes to minstrel_ht_set_rate no further assertion > is needed... > > Regards, > Peter > >> >> Since this concerns mac80211 core, let's add Johannes to the loop as well. >>> >>> >>> -- >>> Jérôme Pouiller >>> >>> > ___ > This email originated from outside of Camlin Group. Do not click on links or open attachments unless you are confident they are secure. If in doubt, please raise a security incident via the following portal: Camlin Helpdesk – Report an Information Security Incident/Non-Conformance <https://camlin-helpdesk.atlassian.net/servicedesk/customer/portal/2/group/34/create/62> >
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 */;