[PATCH] net: ath9k: fix use-after-free in ath9k_hif_usb_rx_cb

Subsystems: atheros ath generic utilities, qualcomm atheros ath9k wireless driver, the rest

STALE1767d

8 messages, 2 authors, 2021-10-02 · open the first message on its own page

[PATCH] net: ath9k: fix use-after-free in ath9k_hif_usb_rx_cb

From: Pavel Skripkin <hidden>
Date: 2021-08-04 19:49:37

Syzbot reported use-after-free Read in ath9k_hif_usb_rx_cb(). The
problem was in incorrect htc_handle->drv_priv initialization.

Probable call trace which can trigger use-after-free:

ath9k_htc_probe_device()
  /* htc_handle->drv_priv = priv; */
  ath9k_htc_wait_for_target()      <--- Failed
  ieee80211_free_hw()		   <--- priv pointer is freed

<IRQ>
...
ath9k_hif_usb_rx_cb()
  ath9k_hif_usb_rx_stream()
   RX_STAT_INC()		<--- htc_handle->drv_priv access

In order to not add fancy protection for drv_priv we can move
htc_handle->drv_priv initialization at the end of the
ath9k_htc_probe_device() and add helper macro to make
all *_STAT_* macros NULL save.

Also, I made whitespaces clean ups in *_STAT_* macros definitions
to make checkpatch.pl happy.

Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.")
Reported-and-tested-by: syzbot+03110230a11411024147@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <redacted>
---

Hi, ath9k maintainer/developers!

I know, that you do not like changes, that wasn't tested on real
hardware. I really don't access to this one, so I'd like you to test it on
real hardware piece, if you have one. At least, this patch was tested by
syzbot [1]

[1] https://syzkaller.appspot.com/bug?id=6ead44e37afb6866ac0c7dd121b4ce07cb665f60

---
 drivers/net/wireless/ath/ath9k/htc.h          | 11 ++++++-----
 drivers/net/wireless/ath/ath9k/htc_drv_init.c |  3 ++-
 2 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/drivers/net/wireless/ath/ath9k/htc.h b/drivers/net/wireless/ath/ath9k/htc.h
index 0a1634238e67..c16b2a482e83 100644
--- a/drivers/net/wireless/ath/ath9k/htc.h
+++ b/drivers/net/wireless/ath/ath9k/htc.h
@@ -326,11 +326,12 @@ static inline struct ath9k_htc_tx_ctl *HTC_SKB_CB(struct sk_buff *skb)
 
 #ifdef CONFIG_ATH9K_HTC_DEBUGFS
 
-#define TX_STAT_INC(c) (hif_dev->htc_handle->drv_priv->debug.tx_stats.c++)
-#define TX_STAT_ADD(c, a) (hif_dev->htc_handle->drv_priv->debug.tx_stats.c += a)
-#define RX_STAT_INC(c) (hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c++)
-#define RX_STAT_ADD(c, a) (hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c += a)
-#define CAB_STAT_INC   priv->debug.tx_stats.cab_queued++
+#define __STAT_SAVE(expr)	(hif_dev->htc_handle->drv_priv ? (expr) : 0)
+#define TX_STAT_INC(c)		__STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.tx_stats.c++)
+#define TX_STAT_ADD(c, a)	__STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.tx_stats.c += a)
+#define RX_STAT_INC(c)		__STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c++)
+#define RX_STAT_ADD(c, a)	__STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c += a)
+#define CAB_STAT_INC		(priv->debug.tx_stats.cab_queued++)
 
 #define TX_QSTAT_INC(q) (priv->debug.tx_stats.queue_stats[q]++)
 
diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_init.c b/drivers/net/wireless/ath/ath9k/htc_drv_init.c
index ff61ae34ecdf..07ac88fb1c57 100644
--- a/drivers/net/wireless/ath/ath9k/htc_drv_init.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_init.c
@@ -944,7 +944,6 @@ int ath9k_htc_probe_device(struct htc_target *htc_handle, struct device *dev,
 	priv->hw = hw;
 	priv->htc = htc_handle;
 	priv->dev = dev;
-	htc_handle->drv_priv = priv;
 	SET_IEEE80211_DEV(hw, priv->dev);
 
 	ret = ath9k_htc_wait_for_target(priv);
@@ -965,6 +964,8 @@ int ath9k_htc_probe_device(struct htc_target *htc_handle, struct device *dev,
 	if (ret)
 		goto err_init;
 
+	htc_handle->drv_priv = priv;
+
 	return 0;
 
 err_init:
-- 
2.32.0

Re: [PATCH] net: ath9k: fix use-after-free in ath9k_hif_usb_rx_cb

From: Pavel Skripkin <hidden>
Date: 2021-08-04 19:57:25

On 8/4/21 10:48 PM, Pavel Skripkin wrote:
quoted hunk
Syzbot reported use-after-free Read in ath9k_hif_usb_rx_cb(). The
problem was in incorrect htc_handle->drv_priv initialization.

Probable call trace which can trigger use-after-free:

ath9k_htc_probe_device()
   /* htc_handle->drv_priv = priv; */
   ath9k_htc_wait_for_target()      <--- Failed
   ieee80211_free_hw()		   <--- priv pointer is freed

<IRQ>
...
ath9k_hif_usb_rx_cb()
   ath9k_hif_usb_rx_stream()
    RX_STAT_INC()		<--- htc_handle->drv_priv access

In order to not add fancy protection for drv_priv we can move
htc_handle->drv_priv initialization at the end of the
ath9k_htc_probe_device() and add helper macro to make
all *_STAT_* macros NULL save.

Also, I made whitespaces clean ups in *_STAT_* macros definitions
to make checkpatch.pl happy.

Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.")
Reported-and-tested-by: syzbot+03110230a11411024147@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <redacted>
---

Hi, ath9k maintainer/developers!

I know, that you do not like changes, that wasn't tested on real
hardware. I really don't access to this one, so I'd like you to test it on
real hardware piece, if you have one. At least, this patch was tested by
syzbot [1]

[1] https://syzkaller.appspot.com/bug?id=6ead44e37afb6866ac0c7dd121b4ce07cb665f60

---
  drivers/net/wireless/ath/ath9k/htc.h          | 11 ++++++-----
  drivers/net/wireless/ath/ath9k/htc_drv_init.c |  3 ++-
  2 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/drivers/net/wireless/ath/ath9k/htc.h b/drivers/net/wireless/ath/ath9k/htc.h
index 0a1634238e67..c16b2a482e83 100644
--- a/drivers/net/wireless/ath/ath9k/htc.h
+++ b/drivers/net/wireless/ath/ath9k/htc.h
@@ -326,11 +326,12 @@ static inline struct ath9k_htc_tx_ctl *HTC_SKB_CB(struct sk_buff *skb)
  
  #ifdef CONFIG_ATH9K_HTC_DEBUGFS
  
-#define TX_STAT_INC(c) (hif_dev->htc_handle->drv_priv->debug.tx_stats.c++)
-#define TX_STAT_ADD(c, a) (hif_dev->htc_handle->drv_priv->debug.tx_stats.c += a)
-#define RX_STAT_INC(c) (hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c++)
-#define RX_STAT_ADD(c, a) (hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c += a)
-#define CAB_STAT_INC   priv->debug.tx_stats.cab_queued++
+#define __STAT_SAVE(expr)	(hif_dev->htc_handle->drv_priv ? (expr) : 0)
+#define TX_STAT_INC(c)		__STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.tx_stats.c++)
+#define TX_STAT_ADD(c, a)	__STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.tx_stats.c += a)
+#define RX_STAT_INC(c)		__STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c++)
+#define RX_STAT_ADD(c, a)	__STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c += a)
+#define CAB_STAT_INC		(priv->debug.tx_stats.cab_queued++)
  
  #define TX_QSTAT_INC(q) (priv->debug.tx_stats.queue_stats[q]++)
  
diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_init.c b/drivers/net/wireless/ath/ath9k/htc_drv_init.c
index ff61ae34ecdf..07ac88fb1c57 100644
--- a/drivers/net/wireless/ath/ath9k/htc_drv_init.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_init.c
@@ -944,7 +944,6 @@ int ath9k_htc_probe_device(struct htc_target *htc_handle, struct device *dev,
  	priv->hw = hw;
  	priv->htc = htc_handle;
  	priv->dev = dev;
-	htc_handle->drv_priv = priv;
  	SET_IEEE80211_DEV(hw, priv->dev);
  
  	ret = ath9k_htc_wait_for_target(priv);
@@ -965,6 +964,8 @@ int ath9k_htc_probe_device(struct htc_target *htc_handle, struct device *dev,
  	if (ret)
  		goto err_init;
  
+	htc_handle->drv_priv = priv;
+
  	return 0;
  
  err_init:
Added missing LKML in CC. Sorry for confusion.


With regards,
Pavel Skripkin

Re: [PATCH] net: ath9k: fix use-after-free in ath9k_hif_usb_rx_cb

From: Kalle Valo <hidden>
Date: 2021-08-06 09:06:36

Pavel Skripkin [off-list ref] writes:
Syzbot reported use-after-free Read in ath9k_hif_usb_rx_cb(). The
problem was in incorrect htc_handle->drv_priv initialization.

Probable call trace which can trigger use-after-free:

ath9k_htc_probe_device()
  /* htc_handle->drv_priv = priv; */
  ath9k_htc_wait_for_target()      <--- Failed
  ieee80211_free_hw()		   <--- priv pointer is freed

<IRQ>
...
ath9k_hif_usb_rx_cb()
  ath9k_hif_usb_rx_stream()
   RX_STAT_INC()		<--- htc_handle->drv_priv access

In order to not add fancy protection for drv_priv we can move
htc_handle->drv_priv initialization at the end of the
ath9k_htc_probe_device() and add helper macro to make
all *_STAT_* macros NULL save.

Also, I made whitespaces clean ups in *_STAT_* macros definitions
to make checkpatch.pl happy.
Separate patch for cleanups, please.
Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.")
Reported-and-tested-by: syzbot+03110230a11411024147@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <redacted>
---

Hi, ath9k maintainer/developers!

I know, that you do not like changes, that wasn't tested on real
hardware. I really don't access to this one, so I'd like you to test it on
real hardware piece, if you have one. At least, this patch was tested by
syzbot [1]

[1] https://syzkaller.appspot.com/bug?id=6ead44e37afb6866ac0c7dd121b4ce07cb665f60
syzbot does not equal testing on real hardware. Can someone test or
review this, please?

-- 
https://patchwork.kernel.org/project/linux-wireless/list/

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

Re: [PATCH] net: ath9k: fix use-after-free in ath9k_hif_usb_rx_cb

From: Pavel Skripkin <hidden>
Date: 2021-08-13 15:01:40

On 8/4/21 10:48 PM, Pavel Skripkin wrote:
Syzbot reported use-after-free Read in ath9k_hif_usb_rx_cb(). The
problem was in incorrect htc_handle->drv_priv initialization.

Probable call trace which can trigger use-after-free:

ath9k_htc_probe_device()
   /* htc_handle->drv_priv = priv; */
   ath9k_htc_wait_for_target()      <--- Failed
   ieee80211_free_hw()		   <--- priv pointer is freed

<IRQ>
...
ath9k_hif_usb_rx_cb()
   ath9k_hif_usb_rx_stream()
    RX_STAT_INC()		<--- htc_handle->drv_priv access

In order to not add fancy protection for drv_priv we can move
htc_handle->drv_priv initialization at the end of the
ath9k_htc_probe_device() and add helper macro to make
all *_STAT_* macros NULL save.

Also, I made whitespaces clean ups in *_STAT_* macros definitions
to make checkpatch.pl happy.

Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.")
Reported-and-tested-by: syzbot+03110230a11411024147@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <redacted>
---

Hi, ath9k maintainer/developers!

I know, that you do not like changes, that wasn't tested on real
hardware. I really don't access to this one, so I'd like you to test it on
real hardware piece, if you have one. At least, this patch was tested by
syzbot [1]

[1] https://syzkaller.appspot.com/bug?id=6ead44e37afb6866ac0c7dd121b4ce07cb665f60

---
Btw, this patch also passes this syzbot test

https://syzkaller.appspot.com/bug?id=b8101ffcec107c0567a0cd8acbbacec91e9ee8de


With regards,
Pavel Skripkin

Re: [PATCH] net: ath9k: fix use-after-free in ath9k_hif_usb_rx_cb

From: Pavel Skripkin <hidden>
Date: 2021-08-31 10:43:58

On 8/4/21 10:57 PM, Pavel Skripkin wrote:
On 8/4/21 10:48 PM, Pavel Skripkin wrote:
quoted
Syzbot reported use-after-free Read in ath9k_hif_usb_rx_cb(). The
problem was in incorrect htc_handle->drv_priv initialization.

Probable call trace which can trigger use-after-free:

ath9k_htc_probe_device()
   /* htc_handle->drv_priv = priv; */
   ath9k_htc_wait_for_target()      <--- Failed
   ieee80211_free_hw()		   <--- priv pointer is freed

<IRQ>
...
ath9k_hif_usb_rx_cb()
   ath9k_hif_usb_rx_stream()
    RX_STAT_INC()		<--- htc_handle->drv_priv access

In order to not add fancy protection for drv_priv we can move
htc_handle->drv_priv initialization at the end of the
ath9k_htc_probe_device() and add helper macro to make
all *_STAT_* macros NULL save.

Also, I made whitespaces clean ups in *_STAT_* macros definitions
to make checkpatch.pl happy.

Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.")
Reported-and-tested-by: syzbot+03110230a11411024147@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <redacted>
---

Hi, ath9k maintainer/developers!

I know, that you do not like changes, that wasn't tested on real
hardware. I really don't access to this one, so I'd like you to test it on
real hardware piece, if you have one. At least, this patch was tested by
syzbot [1]

[1] https://syzkaller.appspot.com/bug?id=6ead44e37afb6866ac0c7dd121b4ce07cb665f60

---
  drivers/net/wireless/ath/ath9k/htc.h          | 11 ++++++-----
  drivers/net/wireless/ath/ath9k/htc_drv_init.c |  3 ++-
  2 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/drivers/net/wireless/ath/ath9k/htc.h b/drivers/net/wireless/ath/ath9k/htc.h
index 0a1634238e67..c16b2a482e83 100644
--- a/drivers/net/wireless/ath/ath9k/htc.h
+++ b/drivers/net/wireless/ath/ath9k/htc.h
@@ -326,11 +326,12 @@ static inline struct ath9k_htc_tx_ctl *HTC_SKB_CB(struct sk_buff *skb)
  
  #ifdef CONFIG_ATH9K_HTC_DEBUGFS
  
-#define TX_STAT_INC(c) (hif_dev->htc_handle->drv_priv->debug.tx_stats.c++)
-#define TX_STAT_ADD(c, a) (hif_dev->htc_handle->drv_priv->debug.tx_stats.c += a)
-#define RX_STAT_INC(c) (hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c++)
-#define RX_STAT_ADD(c, a) (hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c += a)
-#define CAB_STAT_INC   priv->debug.tx_stats.cab_queued++
+#define __STAT_SAVE(expr)	(hif_dev->htc_handle->drv_priv ? (expr) : 0)
+#define TX_STAT_INC(c)		__STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.tx_stats.c++)
+#define TX_STAT_ADD(c, a)	__STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.tx_stats.c += a)
+#define RX_STAT_INC(c)		__STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c++)
+#define RX_STAT_ADD(c, a)	__STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c += a)
+#define CAB_STAT_INC		(priv->debug.tx_stats.cab_queued++)
  
  #define TX_QSTAT_INC(q) (priv->debug.tx_stats.queue_stats[q]++)
  
diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_init.c b/drivers/net/wireless/ath/ath9k/htc_drv_init.c
index ff61ae34ecdf..07ac88fb1c57 100644
--- a/drivers/net/wireless/ath/ath9k/htc_drv_init.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_init.c
@@ -944,7 +944,6 @@ int ath9k_htc_probe_device(struct htc_target *htc_handle, struct device *dev,
  	priv->hw = hw;
  	priv->htc = htc_handle;
  	priv->dev = dev;
-	htc_handle->drv_priv = priv;
  	SET_IEEE80211_DEV(hw, priv->dev);
  
  	ret = ath9k_htc_wait_for_target(priv);
@@ -965,6 +964,8 @@ int ath9k_htc_probe_device(struct htc_target *htc_handle, struct device *dev,
  	if (ret)
  		goto err_init;
  
+	htc_handle->drv_priv = priv;
+
  	return 0;
  
  err_init:
Added missing LKML in CC. Sorry for confusion.
Any chance to review this patch? Thanks




With regards,
Pavel Skripkin

Re: [PATCH] net: ath9k: fix use-after-free in ath9k_hif_usb_rx_cb

From: Pavel Skripkin <hidden>
Date: 2021-09-19 17:28:17

On 8/31/21 13:43, Pavel Skripkin wrote:
On 8/4/21 10:57 PM, Pavel Skripkin wrote:
quoted
On 8/4/21 10:48 PM, Pavel Skripkin wrote:
quoted
Syzbot reported use-after-free Read in ath9k_hif_usb_rx_cb(). The
problem was in incorrect htc_handle->drv_priv initialization.

Probable call trace which can trigger use-after-free:

ath9k_htc_probe_device()
   /* htc_handle->drv_priv = priv; */
   ath9k_htc_wait_for_target()      <--- Failed
   ieee80211_free_hw()		   <--- priv pointer is freed

<IRQ>
...
ath9k_hif_usb_rx_cb()
   ath9k_hif_usb_rx_stream()
    RX_STAT_INC()		<--- htc_handle->drv_priv access

In order to not add fancy protection for drv_priv we can move
htc_handle->drv_priv initialization at the end of the
ath9k_htc_probe_device() and add helper macro to make
all *_STAT_* macros NULL save.

Also, I made whitespaces clean ups in *_STAT_* macros definitions
to make checkpatch.pl happy.

Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.")
Reported-and-tested-by: syzbot+03110230a11411024147@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <redacted>
---

Hi, ath9k maintainer/developers!

I know, that you do not like changes, that wasn't tested on real
hardware. I really don't access to this one, so I'd like you to test it on
real hardware piece, if you have one. At least, this patch was tested by
syzbot [1]

[1] https://syzkaller.appspot.com/bug?id=6ead44e37afb6866ac0c7dd121b4ce07cb665f60

---
  drivers/net/wireless/ath/ath9k/htc.h          | 11 ++++++-----
  drivers/net/wireless/ath/ath9k/htc_drv_init.c |  3 ++-
  2 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/drivers/net/wireless/ath/ath9k/htc.h b/drivers/net/wireless/ath/ath9k/htc.h
index 0a1634238e67..c16b2a482e83 100644
--- a/drivers/net/wireless/ath/ath9k/htc.h
+++ b/drivers/net/wireless/ath/ath9k/htc.h
@@ -326,11 +326,12 @@ static inline struct ath9k_htc_tx_ctl *HTC_SKB_CB(struct sk_buff *skb)
  
  #ifdef CONFIG_ATH9K_HTC_DEBUGFS
  
-#define TX_STAT_INC(c) (hif_dev->htc_handle->drv_priv->debug.tx_stats.c++)
-#define TX_STAT_ADD(c, a) (hif_dev->htc_handle->drv_priv->debug.tx_stats.c += a)
-#define RX_STAT_INC(c) (hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c++)
-#define RX_STAT_ADD(c, a) (hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c += a)
-#define CAB_STAT_INC   priv->debug.tx_stats.cab_queued++
+#define __STAT_SAVE(expr)	(hif_dev->htc_handle->drv_priv ? (expr) : 0)
+#define TX_STAT_INC(c)		__STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.tx_stats.c++)
+#define TX_STAT_ADD(c, a)	__STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.tx_stats.c += a)
+#define RX_STAT_INC(c)		__STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c++)
+#define RX_STAT_ADD(c, a)	__STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c += a)
+#define CAB_STAT_INC		(priv->debug.tx_stats.cab_queued++)
  
  #define TX_QSTAT_INC(q) (priv->debug.tx_stats.queue_stats[q]++)
  
diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_init.c b/drivers/net/wireless/ath/ath9k/htc_drv_init.c
index ff61ae34ecdf..07ac88fb1c57 100644
--- a/drivers/net/wireless/ath/ath9k/htc_drv_init.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_init.c
@@ -944,7 +944,6 @@ int ath9k_htc_probe_device(struct htc_target *htc_handle, struct device *dev,
  	priv->hw = hw;
  	priv->htc = htc_handle;
  	priv->dev = dev;
-	htc_handle->drv_priv = priv;
  	SET_IEEE80211_DEV(hw, priv->dev);
  
  	ret = ath9k_htc_wait_for_target(priv);
@@ -965,6 +964,8 @@ int ath9k_htc_probe_device(struct htc_target *htc_handle, struct device *dev,
  	if (ret)
  		goto err_init;
  
+	htc_handle->drv_priv = priv;
+
  	return 0;
  
  err_init:
Added missing LKML in CC. Sorry for confusion.
Any chance to review this patch? Thanks
gentle ping one more time :) Thanks





With regards,
Pavel Skripkin

[PATCH RESEND] net: ath9k: fix use-after-free in ath9k_hif_usb_rx_cb

From: Pavel Skripkin <hidden>
Date: 2021-09-22 16:42:20

Syzbot reported use-after-free Read in ath9k_hif_usb_rx_cb(). The
problem was in incorrect htc_handle->drv_priv initialization.

Probable call trace which can trigger use-after-free:

ath9k_htc_probe_device()
  /* htc_handle->drv_priv = priv; */
  ath9k_htc_wait_for_target()      <--- Failed
  ieee80211_free_hw()		   <--- priv pointer is freed

<IRQ>
...
ath9k_hif_usb_rx_cb()
  ath9k_hif_usb_rx_stream()
   RX_STAT_INC()		<--- htc_handle->drv_priv access

In order to not add fancy protection for drv_priv we can move
htc_handle->drv_priv initialization at the end of the
ath9k_htc_probe_device() and add helper macro to make
all *_STAT_* macros NULL save.

Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.")
Reported-and-tested-by: syzbot+03110230a11411024147@syzkaller.appspotmail.com
Reported-and-tested-by: syzbot+c6dde1f690b60e0b9fbe@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <redacted>
---

Why resend?
	No activity on this patch since 8/6/21, Kalle Valo has asked around,
	for review and no one claimed it.

Resend changes:
	1. Rebased on top of v5.15-rc2
	2. Removed clean ups for macros
	3. Added 1 more syzbot tag, since this patch has passed 2 syzbot
	tests

---
 drivers/net/wireless/ath/ath9k/htc.h          | 10 +++++-----
 drivers/net/wireless/ath/ath9k/htc_drv_init.c |  3 ++-
 2 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/net/wireless/ath/ath9k/htc.h b/drivers/net/wireless/ath/ath9k/htc.h
index 0a1634238e67..c8cde2e05d77 100644
--- a/drivers/net/wireless/ath/ath9k/htc.h
+++ b/drivers/net/wireless/ath/ath9k/htc.h
@@ -325,11 +325,11 @@ static inline struct ath9k_htc_tx_ctl *HTC_SKB_CB(struct sk_buff *skb)
 }
 
 #ifdef CONFIG_ATH9K_HTC_DEBUGFS
-
-#define TX_STAT_INC(c) (hif_dev->htc_handle->drv_priv->debug.tx_stats.c++)
-#define TX_STAT_ADD(c, a) (hif_dev->htc_handle->drv_priv->debug.tx_stats.c += a)
-#define RX_STAT_INC(c) (hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c++)
-#define RX_STAT_ADD(c, a) (hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c += a)
+#define __STAT_SAVE(expr) (hif_dev->htc_handle->drv_priv ? (expr) : 0)
+#define TX_STAT_INC(c) __STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.tx_stats.c++)
+#define TX_STAT_ADD(c, a) __STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.tx_stats.c += a)
+#define RX_STAT_INC(c) __STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c++)
+#define RX_STAT_ADD(c, a) __STAT_SAVE(hif_dev->htc_handle->drv_priv->debug.skbrx_stats.c += a)
 #define CAB_STAT_INC   priv->debug.tx_stats.cab_queued++
 
 #define TX_QSTAT_INC(q) (priv->debug.tx_stats.queue_stats[q]++)
diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_init.c b/drivers/net/wireless/ath/ath9k/htc_drv_init.c
index ff61ae34ecdf..07ac88fb1c57 100644
--- a/drivers/net/wireless/ath/ath9k/htc_drv_init.c
+++ b/drivers/net/wireless/ath/ath9k/htc_drv_init.c
@@ -944,7 +944,6 @@ int ath9k_htc_probe_device(struct htc_target *htc_handle, struct device *dev,
 	priv->hw = hw;
 	priv->htc = htc_handle;
 	priv->dev = dev;
-	htc_handle->drv_priv = priv;
 	SET_IEEE80211_DEV(hw, priv->dev);
 
 	ret = ath9k_htc_wait_for_target(priv);
@@ -965,6 +964,8 @@ int ath9k_htc_probe_device(struct htc_target *htc_handle, struct device *dev,
 	if (ret)
 		goto err_init;
 
+	htc_handle->drv_priv = priv;
+
 	return 0;
 
 err_init:
-- 
2.33.0

Re: [PATCH RESEND] net: ath9k: fix use-after-free in ath9k_hif_usb_rx_cb

From: Pavel Skripkin <hidden>
Date: 2021-10-02 13:05:56

On 9/22/21 19:42, Pavel Skripkin wrote:
Syzbot reported use-after-free Read in ath9k_hif_usb_rx_cb(). The
problem was in incorrect htc_handle->drv_priv initialization.

Probable call trace which can trigger use-after-free:

ath9k_htc_probe_device()
   /* htc_handle->drv_priv = priv; */
   ath9k_htc_wait_for_target()      <--- Failed
   ieee80211_free_hw()		   <--- priv pointer is freed

<IRQ>
...
ath9k_hif_usb_rx_cb()
   ath9k_hif_usb_rx_stream()
    RX_STAT_INC()		<--- htc_handle->drv_priv access

In order to not add fancy protection for drv_priv we can move
htc_handle->drv_priv initialization at the end of the
ath9k_htc_probe_device() and add helper macro to make
all *_STAT_* macros NULL save.

Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.")
Reported-and-tested-by: syzbot+03110230a11411024147@syzkaller.appspotmail.com
Reported-and-tested-by: syzbot+c6dde1f690b60e0b9fbe@syzkaller.appspotmail.com
Signed-off-by: Pavel Skripkin <redacted>
---

Why resend?
	No activity on this patch since 8/6/21, Kalle Valo has asked around,
	for review and no one claimed it.

Resend changes:
	1. Rebased on top of v5.15-rc2
	2. Removed clean ups for macros
	3. Added 1 more syzbot tag, since this patch has passed 2 syzbot
	tests
Hi, ath9k maintainers!

Does this patch need any further work? I can't see any comments on it 
since 8/6/21 and I can't see it on wireless patchwork.

If this bug is already fixed and I've overlooked a fix commit, please, 
let me know. As I see syzbot hits this bug really often [1]

Thanks


[1] 
https://syzkaller.appspot.com/bug?id=6ead44e37afb6866ac0c7dd121b4ce07cb665f60




With regards,
Pavel Skripkin
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