[PATCH] rtlwifi: Fix null-pointer dereferences in error handling code of rtl_pci_probe()

[PATCH] rtlwifi: Fix null-pointer dereferences in error handling code of rtl_pci_probe()

[Jia-Ju Bai]

*BUG 1:
In rtl_pci_probe(), when rtlpriv->cfg->ops->init_sw_vars() fails,
rtl_deinit_core() in the error handling code is executed.
rtl_deinit_core() calls rtl_free_entries_from_scan_list(), which uses
rtlpriv->scan_list.list in list_for_each_entry_safe(), but it has been
initialized. Thus a null-pointer dereference occurs.
The reason is that rtlpriv->scan_list.list is initialized by
INIT_LIST_HEAD() in rtl_init_core(), which has not been called.

To fix this bug, rtl_deinit_core() should not be called when
rtlpriv->cfg->ops->init_sw_vars() fails.

*BUG 2:
In rtl_pci_probe(), rtl_init_core() can fail when rtl_regd_init() in
this function fails, and rtlpriv->scan_list.list has not been
initialized by INIT_LIST_HEAD(). Then, rtl_deinit_core() in the error
handling code of rtl_pci_probe() is executed. Finally, a null-pointer
dereference occurs due to the same reason of the above bug.

To fix this bug, the initialization of lists in rtl_init_core() are
performed before the call to rtl_regd_init().

These bugs are found by a runtime fuzzing tool named FIZZER written by
us.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
 drivers/net/wireless/realtek/rtlwifi/base.c | 15 ++++++++-------
 drivers/net/wireless/realtek/rtlwifi/pci.c  |  4 ++--
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtlwifi/base.c b/drivers/net/wireless/realtek/rtlwifi/base.c
index 217d2a7a43c7..b3f341ec3710 100644
--- a/drivers/net/wireless/realtek/rtlwifi/base.c
+++ b/drivers/net/wireless/realtek/rtlwifi/base.c
@@ -526,8 +526,14 @@ int rtl_init_core(struct ieee80211_hw *hw)
 	/* <2> rate control register */
 	hw->rate_control_algorithm = "rtl_rc";
 
+	/* <3> init list */
+	INIT_LIST_HEAD(&rtlpriv->entry_list);
+	INIT_LIST_HEAD(&rtlpriv->scan_list.list);
+	skb_queue_head_init(&rtlpriv->tx_report.queue);
+	skb_queue_head_init(&rtlpriv->c2hcmd_queue);
+
 	/*
-	 * <3> init CRDA must come after init
+	 * <4> init CRDA must come after init
 	 * mac80211 hw  in _rtl_init_mac80211.
 	 */
 	if (rtl_regd_init(hw, rtl_reg_notifier)) {
@@ -535,7 +541,7 @@ int rtl_init_core(struct ieee80211_hw *hw)
 		return 1;
 	}
 
-	/* <4> locks */
+	/* <5> locks */
 	mutex_init(&rtlpriv->locks.conf_mutex);
 	mutex_init(&rtlpriv->locks.ips_mutex);
 	mutex_init(&rtlpriv->locks.lps_mutex);
@@ -550,11 +556,6 @@ int rtl_init_core(struct ieee80211_hw *hw)
 	spin_lock_init(&rtlpriv->locks.cck_and_rw_pagea_lock);
 	spin_lock_init(&rtlpriv->locks.fw_ps_lock);
 	spin_lock_init(&rtlpriv->locks.iqk_lock);
-	/* <5> init list */
-	INIT_LIST_HEAD(&rtlpriv->entry_list);
-	INIT_LIST_HEAD(&rtlpriv->scan_list.list);
-	skb_queue_head_init(&rtlpriv->tx_report.queue);
-	skb_queue_head_init(&rtlpriv->c2hcmd_queue);
 
 	rtlmac->link_state = MAC80211_NOLINK;
 
diff --git a/drivers/net/wireless/realtek/rtlwifi/pci.c b/drivers/net/wireless/realtek/rtlwifi/pci.c
index 48ca52102cef..864cb76230c4 100644
--- a/drivers/net/wireless/realtek/rtlwifi/pci.c
+++ b/drivers/net/wireless/realtek/rtlwifi/pci.c
@@ -2267,7 +2267,7 @@ int rtl_pci_probe(struct pci_dev *pdev,
 	if (rtlpriv->cfg->ops->init_sw_vars(hw)) {
 		pr_err("Can't init_sw_vars\n");
 		err = -ENODEV;
-		goto fail3;
+		goto fail2;
 	}
 	rtlpriv->cfg->ops->init_sw_leds(hw);
-- 
2.17.0

Re: [PATCH] rtlwifi: Fix null-pointer dereferences in error handling code of rtl_pci_probe()

[Kalle Valo]

Jia-Ju Bai <baijiaju1990@gmail.com> wrote:

> *BUG 1:
> In rtl_pci_probe(), when rtlpriv->cfg->ops->init_sw_vars() fails,
> rtl_deinit_core() in the error handling code is executed.
> rtl_deinit_core() calls rtl_free_entries_from_scan_list(), which uses
> rtlpriv->scan_list.list in list_for_each_entry_safe(), but it has been
> initialized. Thus a null-pointer dereference occurs.
> The reason is that rtlpriv->scan_list.list is initialized by
> INIT_LIST_HEAD() in rtl_init_core(), which has not been called.
> 
> To fix this bug, rtl_deinit_core() should not be called when
> rtlpriv->cfg->ops->init_sw_vars() fails.
> 
> *BUG 2:
> In rtl_pci_probe(), rtl_init_core() can fail when rtl_regd_init() in
> this function fails, and rtlpriv->scan_list.list has not been
> initialized by INIT_LIST_HEAD(). Then, rtl_deinit_core() in the error
> handling code of rtl_pci_probe() is executed. Finally, a null-pointer
> dereference occurs due to the same reason of the above bug.
> 
> To fix this bug, the initialization of lists in rtl_init_core() are
> performed before the call to rtl_regd_init().
> 
> These bugs are found by a runtime fuzzing tool named FIZZER written by
> us.
> 
> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>

Ping & Larry, is this ok to take?

-- 
https://patchwork.kernel.org/patch/10942971/

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

Re: [PATCH] rtlwifi: Fix null-pointer dereferences in error handling code of rtl_pci_probe()

[Larry Finger]

On 5/28/19 6:55 AM, Kalle Valo wrote:
> Jia-Ju Bai <baijiaju1990@gmail.com> wrote:
> 
>> *BUG 1:
>> In rtl_pci_probe(), when rtlpriv->cfg->ops->init_sw_vars() fails,
>> rtl_deinit_core() in the error handling code is executed.
>> rtl_deinit_core() calls rtl_free_entries_from_scan_list(), which uses
>> rtlpriv->scan_list.list in list_for_each_entry_safe(), but it has been
>> initialized. Thus a null-pointer dereference occurs.
>> The reason is that rtlpriv->scan_list.list is initialized by
>> INIT_LIST_HEAD() in rtl_init_core(), which has not been called.
>>
>> To fix this bug, rtl_deinit_core() should not be called when
>> rtlpriv->cfg->ops->init_sw_vars() fails.
>>
>> *BUG 2:
>> In rtl_pci_probe(), rtl_init_core() can fail when rtl_regd_init() in
>> this function fails, and rtlpriv->scan_list.list has not been
>> initialized by INIT_LIST_HEAD(). Then, rtl_deinit_core() in the error
>> handling code of rtl_pci_probe() is executed. Finally, a null-pointer
>> dereference occurs due to the same reason of the above bug.
>>
>> To fix this bug, the initialization of lists in rtl_init_core() are
>> performed before the call to rtl_regd_init().
>>
>> These bugs are found by a runtime fuzzing tool named FIZZER written by
>> us.
>>
>> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
> 
> Ping & Larry, is this ok to take?
> 

Kalle,

Not at the moment. In reviewing the code, I was unable to see how this situation 
could develop, and his backtrace did not mention any rtlwifi code. For that 
reason, I asked him to add printk stat4ements to show the last part of rtl_pci 
that executed correctly. In 
https://marc.info/?l=linux-wireless&m=155788322631134&w=2, he promised to do 
that, but I have not seen the result.

Larry

Re: [PATCH] rtlwifi: Fix null-pointer dereferences in error handling code of rtl_pci_probe()

[Kalle Valo]

Larry Finger <Larry.Finger@lwfinger.net> writes:

> On 5/28/19 6:55 AM, Kalle Valo wrote:
>> Jia-Ju Bai <baijiaju1990@gmail.com> wrote:
>>
>>> *BUG 1:
>>> In rtl_pci_probe(), when rtlpriv->cfg->ops->init_sw_vars() fails,
>>> rtl_deinit_core() in the error handling code is executed.
>>> rtl_deinit_core() calls rtl_free_entries_from_scan_list(), which uses
>>> rtlpriv->scan_list.list in list_for_each_entry_safe(), but it has been
>>> initialized. Thus a null-pointer dereference occurs.
>>> The reason is that rtlpriv->scan_list.list is initialized by
>>> INIT_LIST_HEAD() in rtl_init_core(), which has not been called.
>>>
>>> To fix this bug, rtl_deinit_core() should not be called when
>>> rtlpriv->cfg->ops->init_sw_vars() fails.
>>>
>>> *BUG 2:
>>> In rtl_pci_probe(), rtl_init_core() can fail when rtl_regd_init() in
>>> this function fails, and rtlpriv->scan_list.list has not been
>>> initialized by INIT_LIST_HEAD(). Then, rtl_deinit_core() in the error
>>> handling code of rtl_pci_probe() is executed. Finally, a null-pointer
>>> dereference occurs due to the same reason of the above bug.
>>>
>>> To fix this bug, the initialization of lists in rtl_init_core() are
>>> performed before the call to rtl_regd_init().
>>>
>>> These bugs are found by a runtime fuzzing tool named FIZZER written by
>>> us.
>>>
>>> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
>>
>> Ping & Larry, is this ok to take?
>>
>
> Kalle,
>
> Not at the moment. In reviewing the code, I was unable to see how this
> situation could develop, and his backtrace did not mention any rtlwifi
> code. For that reason, I asked him to add printk stat4ements to show
> the last part of rtl_pci that executed correctly. In
> https://marc.info/?l=linux-wireless&m=155788322631134&w=2, he promised
> to do that, but I have not seen the result.

Ok, thanks. I'll then drop this, please resubmit once everything is
understood and the patch is ready to be applied.

-- 
Kalle Valo

Re: [PATCH] rtlwifi: Fix null-pointer dereferences in error handling code of rtl_pci_probe()

[Jia-Ju Bai]

On 2019/5/28 21:00, Larry Finger wrote:
> On 5/28/19 6:55 AM, Kalle Valo wrote:
>> Jia-Ju Bai <baijiaju1990@gmail.com> wrote:
>>
>>> *BUG 1:
>>> In rtl_pci_probe(), when rtlpriv->cfg->ops->init_sw_vars() fails,
>>> rtl_deinit_core() in the error handling code is executed.
>>> rtl_deinit_core() calls rtl_free_entries_from_scan_list(), which uses
>>> rtlpriv->scan_list.list in list_for_each_entry_safe(), but it has been
>>> initialized. Thus a null-pointer dereference occurs.
>>> The reason is that rtlpriv->scan_list.list is initialized by
>>> INIT_LIST_HEAD() in rtl_init_core(), which has not been called.
>>>
>>> To fix this bug, rtl_deinit_core() should not be called when
>>> rtlpriv->cfg->ops->init_sw_vars() fails.
>>>
>>> *BUG 2:
>>> In rtl_pci_probe(), rtl_init_core() can fail when rtl_regd_init() in
>>> this function fails, and rtlpriv->scan_list.list has not been
>>> initialized by INIT_LIST_HEAD(). Then, rtl_deinit_core() in the error
>>> handling code of rtl_pci_probe() is executed. Finally, a null-pointer
>>> dereference occurs due to the same reason of the above bug.
>>>
>>> To fix this bug, the initialization of lists in rtl_init_core() are
>>> performed before the call to rtl_regd_init().
>>>
>>> These bugs are found by a runtime fuzzing tool named FIZZER written by
>>> us.
>>>
>>> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
>>
>> Ping & Larry, is this ok to take?
>>
>
> Kalle,
>
> Not at the moment. In reviewing the code, I was unable to see how this 
> situation could develop, and his backtrace did not mention any rtlwifi 
> code. For that reason, I asked him to add printk stat4ements to show 
> the last part of rtl_pci that executed correctly. In 
> https://marc.info/?l=linux-wireless&m=155788322631134&w=2, he promised 
> to do that, but I have not seen the result.
>

Hi Larry,

This patch is not related to the message you mentioned.
That message is about an occasional crash that I reported.
That crash occurred when request_irq() in rtl_pci_intr_mode_legacy() in 
rtl_pci_intr_mode_decide() fails.
I have added printk statements and try to reproduce and debug that 
crash, but that crash does not always occur, and I still do not know the 
root cause of that crash.

The null-pointer dereferences fixed by this patch are different from 
that crash, and they always occur when the related functions fail.
So please review these null-pointer dereferences, thanks :)


Best wishes,
Jia-Ju Bai

Re: [PATCH] rtlwifi: Fix null-pointer dereferences in error handling code of rtl_pci_probe()

[Larry Finger]

On 5/29/19 5:30 AM, Jia-Ju Bai wrote:
> 
> 
> On 2019/5/28 21:00, Larry Finger wrote:
>> On 5/28/19 6:55 AM, Kalle Valo wrote:
>>> Jia-Ju Bai <baijiaju1990@gmail.com> wrote:
>>>
>>>> *BUG 1:
>>>> In rtl_pci_probe(), when rtlpriv->cfg->ops->init_sw_vars() fails,
>>>> rtl_deinit_core() in the error handling code is executed.
>>>> rtl_deinit_core() calls rtl_free_entries_from_scan_list(), which uses
>>>> rtlpriv->scan_list.list in list_for_each_entry_safe(), but it has been
>>>> initialized. Thus a null-pointer dereference occurs.
>>>> The reason is that rtlpriv->scan_list.list is initialized by
>>>> INIT_LIST_HEAD() in rtl_init_core(), which has not been called.
>>>>
>>>> To fix this bug, rtl_deinit_core() should not be called when
>>>> rtlpriv->cfg->ops->init_sw_vars() fails.
>>>>
>>>> *BUG 2:
>>>> In rtl_pci_probe(), rtl_init_core() can fail when rtl_regd_init() in
>>>> this function fails, and rtlpriv->scan_list.list has not been
>>>> initialized by INIT_LIST_HEAD(). Then, rtl_deinit_core() in the error
>>>> handling code of rtl_pci_probe() is executed. Finally, a null-pointer
>>>> dereference occurs due to the same reason of the above bug.
>>>>
>>>> To fix this bug, the initialization of lists in rtl_init_core() are
>>>> performed before the call to rtl_regd_init().
>>>>
>>>> These bugs are found by a runtime fuzzing tool named FIZZER written by
>>>> us.
>>>>
>>>> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
>>>
>>> Ping & Larry, is this ok to take?
>>>
>>
>> Kalle,
>>
>> Not at the moment. In reviewing the code, I was unable to see how this 
>> situation could develop, and his backtrace did not mention any rtlwifi code. 
>> For that reason, I asked him to add printk stat4ements to show the last part 
>> of rtl_pci that executed correctly. In 
>> https://marc.info/?l=linux-wireless&m=155788322631134&w=2, he promised to do 
>> that, but I have not seen the result.
>>
> 
> Hi Larry,
> 
> This patch is not related to the message you mentioned.
> That message is about an occasional crash that I reported.
> That crash occurred when request_irq() in rtl_pci_intr_mode_legacy() in 
> rtl_pci_intr_mode_decide() fails.
> I have added printk statements and try to reproduce and debug that crash, but 
> that crash does not always occur, and I still do not know the root cause of that 
> crash.
> 
> The null-pointer dereferences fixed by this patch are different from that crash, 
> and they always occur when the related functions fail.
> So please review these null-pointer dereferences, thanks :)
> 
> 
> Best wishes,
> Jia-Ju Bai

Sorry if I got confused. Kalle has dropped this patch, thus you will need to 
submit a new version.

Larry