From be92292b90bfdc31f332c962882b6d3ea0285fdf Mon Sep 17 00:00:00 2001 From: =?utf8?q?Pawe=C5=82=20Lenkow?= Date: Mon, 19 Sep 2022 17:01:35 +0200 Subject: [PATCH] wifi: mac80211: fix memory corruption in minstrel_ht_update_rates() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 After discussion on the wireless mailing list it was clarified that the issue has been introduced by: commit ee0e16ab756a ("mac80211: minstrel_ht: fill all requested rates") and fix shall be in minstrel_ht_update_rates in rc80211_minstrel_ht.c. Fixes: ee0e16ab756a ("mac80211: minstrel_ht: fill all requested rates") Link: https://lore.kernel.org/all/12e5adcd-8aed-f0f7-70cc-4fb7b656b829@camlingroup.com/ Link: https://lore.kernel.org/linux-wireless/20220915131445.30600-1-lech.perczak@camlingroup.com/ Cc: Jérôme Pouiller Cc: Johannes Berg Cc: Peter Seiderer Cc: Kalle Valo Cc: Krzysztof Drobiński , Signed-off-by: Paweł Lenkow Signed-off-by: Lech Perczak Reviewed-by: Peter Seiderer Reviewed-by: Jérôme Pouiller Acked-by: Felix Fietkau Signed-off-by: Johannes Berg --- net/mac80211/rc80211_minstrel_ht.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c index 5f27e6746762..788a82f9c74d 100644 --- a/net/mac80211/rc80211_minstrel_ht.c +++ b/net/mac80211/rc80211_minstrel_ht.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include "rate.h" #include "sta_info.h" @@ -1550,6 +1551,7 @@ minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) { struct ieee80211_sta_rates *rates; int i = 0; + int max_rates = min_t(int, mp->hw->max_rates, IEEE80211_TX_RATE_TABLE_SIZE); rates = kzalloc(sizeof(*rates), GFP_ATOMIC); if (!rates) @@ -1559,10 +1561,10 @@ 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 < (max_rates - 1); i++) minstrel_ht_set_rate(mp, mi, rates, i, mi->max_tp_rate[i]); - if (i < mp->hw->max_rates) + if (i < max_rates) minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate); if (i < IEEE80211_TX_RATE_TABLE_SIZE) -- 2.34.1