2021-11-25 09:33:14

by Sriram R

Subject: [PATCH] ath11k: Avoid NULL ptr access during mgmt tx cleanup

Currently 'ar' reference is not added in skb_cb during
WMI mgmt tx. Though this is generally not used during tx completion
callbacks, on interface removal the remaining idr cleanup callback
uses the ar ptr from skb_cb from mgmt txmgmt_idr. Hence
fill them during tx call for proper usage.

Also free the skb which is missing currently in these
callbacks.

Crash_info:

[19282.489476] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[19282.489515] pgd = 91eb8000
[19282.496702] [00000000] *pgd=00000000
[19282.502524] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
[19282.783728] PC is at ath11k_mac_vif_txmgmt_idr_remove+0x28/0xd8 [ath11k]
[19282.789170] LR is at idr_for_each+0xa0/0xc8

Tested-on: IPQ8074 hw2.0 AHB WLAN.HK.2.5.0.1-00729-QCAHKSWPL_SILICONZ-3 v2
Signed-off-by: Sriram R <[email protected]>
---
drivers/net/wireless/ath/ath11k/mac.c | 35 ++++++++++++++++++++---------------
1 file changed, 20 insertions(+), 15 deletions(-)

diff --git a/drivers/net/wireless/ath/ath11k/mac.c b/drivers/net/wireless/ath/ath11k/mac.c
index 06d2065..0050e2c 100644
--- a/drivers/net/wireless/ath/ath11k/mac.c
+++ b/drivers/net/wireless/ath/ath11k/mac.c
@@ -1,6 +1,7 @@
// SPDX-License-Identifier: BSD-3-Clause-Clear
/*
* Copyright (c) 2018-2019 The Linux Foundation. All rights reserved.
+ * Copyright (c) 2021 Qualcomm Innovation Center, Inc. All rights reserved.
*/

#include <net/mac80211.h>
@@ -5224,23 +5225,32 @@ static int __ath11k_set_antenna(struct ath11k *ar, u32 tx_ant, u32 rx_ant)
return 0;
}

-int ath11k_mac_tx_mgmt_pending_free(int buf_id, void *skb, void *ctx)
+static void ath11k_mac_tx_mgmt_free(struct ath11k *ar, int buf_id)
{
- struct sk_buff *msdu = skb;
+ struct sk_buff *msdu;
struct ieee80211_tx_info *info;
- struct ath11k *ar = ctx;
- struct ath11k_base *ab = ar->ab;

spin_lock_bh(&ar->txmgmt_idr_lock);
- idr_remove(&ar->txmgmt_idr, buf_id);
+ msdu = idr_remove(&ar->txmgmt_idr, buf_id);
spin_unlock_bh(&ar->txmgmt_idr_lock);
- dma_unmap_single(ab->dev, ATH11K_SKB_CB(msdu)->paddr, msdu->len,
+
+ if (!msdu)
+ return;
+
+ dma_unmap_single(ar->ab->dev, ATH11K_SKB_CB(msdu)->paddr, msdu->len,
DMA_TO_DEVICE);

info = IEEE80211_SKB_CB(msdu);
memset(&info->status, 0, sizeof(info->status));

ieee80211_free_txskb(ar->hw, msdu);
+}
+
+int ath11k_mac_tx_mgmt_pending_free(int buf_id, void *skb, void *ctx)
+{
+ struct ath11k *ar = ctx;
+
+ ath11k_mac_tx_mgmt_free(ar, buf_id);

return 0;
}
@@ -5249,17 +5259,10 @@ static int ath11k_mac_vif_txmgmt_idr_remove(int buf_id, void *skb, void *ctx)
{
struct ieee80211_vif *vif = ctx;
struct ath11k_skb_cb *skb_cb = ATH11K_SKB_CB((struct sk_buff *)skb);
- struct sk_buff *msdu = skb;
struct ath11k *ar = skb_cb->ar;
- struct ath11k_base *ab = ar->ab;

- if (skb_cb->vif == vif) {
- spin_lock_bh(&ar->txmgmt_idr_lock);
- idr_remove(&ar->txmgmt_idr, buf_id);
- spin_unlock_bh(&ar->txmgmt_idr_lock);
- dma_unmap_single(ab->dev, skb_cb->paddr, msdu->len,
- DMA_TO_DEVICE);
- }
+ if (skb_cb->vif == vif)
+ ath11k_mac_tx_mgmt_free(ar, buf_id);

return 0;
}
@@ -5274,6 +5277,8 @@ static int ath11k_mac_mgmt_tx_wmi(struct ath11k *ar, struct ath11k_vif *arvif,
int buf_id;
int ret;

+ ATH11K_SKB_CB(skb)->ar = ar;
+
spin_lock_bh(&ar->txmgmt_idr_lock);
buf_id = idr_alloc(&ar->txmgmt_idr, skb, 0,
ATH11K_TX_MGMT_NUM_PENDING_MAX, GFP_ATOMIC);
--
2.7.4

2021-11-29 15:49:11

by Kalle Valo

Subject: Re: [PATCH] ath11k: Avoid NULL ptr access during mgmt tx cleanup

Sriram R <[email protected]> wrote:

> Currently 'ar' reference is not added in skb_cb during
> WMI mgmt tx. Though this is generally not used during tx completion
> callbacks, on interface removal the remaining idr cleanup callback
> uses the ar ptr from skb_cb from mgmt txmgmt_idr. Hence
> fill them during tx call for proper usage.
>
> Also free the skb which is missing currently in these
> callbacks.
>
> Crash_info:
>
> [19282.489476] Unable to handle kernel NULL pointer dereference at virtual address 00000000
> [19282.489515] pgd = 91eb8000
> [19282.496702] [00000000] *pgd=00000000
> [19282.502524] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
> [19282.783728] PC is at ath11k_mac_vif_txmgmt_idr_remove+0x28/0xd8 [ath11k]
> [19282.789170] LR is at idr_for_each+0xa0/0xc8
>
> Tested-on: IPQ8074 hw2.0 AHB WLAN.HK.2.5.0.1-00729-QCAHKSWPL_SILICONZ-3 v2
> Signed-off-by: Sriram R <[email protected]>
> Signed-off-by: Kalle Valo <[email protected]>

Patch applied to ath-next branch of ath.git, thanks.

a93789ae541c ath11k: Avoid NULL ptr access during mgmt tx cleanup

--
https://patchwork.kernel.org/project/linux-wireless/patch/[email protected]/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches