In a previous commit 69403bad97aa ("wifi: mac80211: sdata can be NULL
during AMPDU start"), sta->sdata can be NULL, and thus it should be
checked before being used.
However, in the same call stack, sta->sdata is also used in the
following functions:
ieee80211_ba_session_work()
___ieee80211_stop_rx_ba_session(sta)
ht_dbg(sta->sdata, ...); -> No check
sdata_info(sta->sdata, ...); -> No check
ieee80211_send_delba(sta->sdata, ...) -> No check
___ieee80211_start_rx_ba_session(sta)
ht_dbg(sta->sdata, ...); -> No check
ht_dbg_ratelimited(sta->sdata, ...); -> No check
ieee80211_tx_ba_session_handle_start(sta)
sdata = sta->sdata; if (!sdata) -> Add check by previous commit
___ieee80211_stop_tx_ba_session(sdata)
ht_dbg(sta->sdata, ...); -> No check
ieee80211_start_tx_ba_cb(sdata)
sdata = sta->sdata; local = sdata->local -> No check
ieee80211_stop_tx_ba_cb(sdata)
ht_dbg(sta->sdata, ...); -> No check
Thus, to avoid possible null-pointer dereferences, the related checks
should be added.
These bugs are reported by a static analysis tool implemented by myself,
and they are found by extending a known bug fixed in the previous commit.
Thus, they could be theoretical bugs.
Signed-off-by: Jia-Ju Bai <[email protected]>
---
v2:
* Fix an error reported by checkpatch.pl, and make the bug finding
process more clear in the description. Thanks for Simon's advice.
---
net/mac80211/agg-rx.c | 68 ++++++++++++++++++++++++++-----------------
net/mac80211/agg-tx.c | 16 ++++++++--
2 files changed, 55 insertions(+), 29 deletions(-)
diff --git a/net/mac80211/agg-rx.c b/net/mac80211/agg-rx.c
index c6fa53230450..6616970785a2 100644
--- a/net/mac80211/agg-rx.c
+++ b/net/mac80211/agg-rx.c
@@ -80,19 +80,21 @@ void ___ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
RCU_INIT_POINTER(sta->ampdu_mlme.tid_rx[tid], NULL);
__clear_bit(tid, sta->ampdu_mlme.agg_session_valid);
- ht_dbg(sta->sdata,
- "Rx BA session stop requested for %pM tid %u %s reason: %d\n",
- sta->sta.addr, tid,
- initiator == WLAN_BACK_RECIPIENT ? "recipient" : "initiator",
- (int)reason);
+ if (sta->sdata) {
+ ht_dbg(sta->sdata,
+ "Rx BA session stop requested for %pM tid %u %s reason: %d\n",
+ sta->sta.addr, tid,
+ initiator == WLAN_BACK_RECIPIENT ? "recipient" : "initiator",
+ (int)reason);
+ }
- if (drv_ampdu_action(local, sta->sdata, ¶ms))
+ if (sta->sdata && drv_ampdu_action(local, sta->sdata, ¶ms))
sdata_info(sta->sdata,
"HW problem - can not stop rx aggregation for %pM tid %d\n",
sta->sta.addr, tid);
/* check if this is a self generated aggregation halt */
- if (initiator == WLAN_BACK_RECIPIENT && tx)
+ if (initiator == WLAN_BACK_RECIPIENT && tx && sta->sdata)
ieee80211_send_delba(sta->sdata, sta->sta.addr,
tid, WLAN_BACK_RECIPIENT, reason);
@@ -279,17 +281,21 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
if (!sta->sta.deflink.ht_cap.ht_supported &&
!sta->sta.deflink.he_cap.has_he) {
- ht_dbg(sta->sdata,
- "STA %pM erroneously requests BA session on tid %d w/o HT\n",
- sta->sta.addr, tid);
+ if (sta->sdata) {
+ ht_dbg(sta->sdata,
+ "STA %pM erroneously requests BA session on tid %d w/o HT\n",
+ sta->sta.addr, tid);
+ }
/* send a response anyway, it's an error case if we get here */
goto end;
}
if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
- ht_dbg(sta->sdata,
- "Suspend in progress - Denying ADDBA request (%pM tid %d)\n",
- sta->sta.addr, tid);
+ if (sta->sdata) {
+ ht_dbg(sta->sdata,
+ "Suspend in progress - Denying ADDBA request (%pM tid %d)\n",
+ sta->sta.addr, tid);
+ }
goto end;
}
@@ -322,8 +328,10 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
buf_size = sta->sta.max_rx_aggregation_subframes;
params.buf_size = buf_size;
- ht_dbg(sta->sdata, "AddBA Req buf_size=%d for %pM\n",
- buf_size, sta->sta.addr);
+ if (sta->sdata) {
+ ht_dbg(sta->sdata, "AddBA Req buf_size=%d for %pM\n",
+ buf_size, sta->sta.addr);
+ }
/* examine state machine */
lockdep_assert_held(&sta->ampdu_mlme.mtx);
@@ -332,9 +340,11 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
if (sta->ampdu_mlme.tid_rx_token[tid] == dialog_token) {
struct tid_ampdu_rx *tid_rx;
- ht_dbg_ratelimited(sta->sdata,
- "updated AddBA Req from %pM on tid %u\n",
- sta->sta.addr, tid);
+ if (sta->sdata) {
+ ht_dbg_ratelimited(sta->sdata,
+ "updated AddBA Req from %pM on tid %u\n",
+ sta->sta.addr, tid);
+ }
/* We have no API to update the timeout value in the
* driver so reject the timeout update if the timeout
* changed. If it did not change, i.e., no real update,
@@ -350,9 +360,11 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
goto end;
}
- ht_dbg_ratelimited(sta->sdata,
- "unexpected AddBA Req from %pM on tid %u\n",
- sta->sta.addr, tid);
+ if (sta->sdata) {
+ ht_dbg_ratelimited(sta->sdata,
+ "unexpected AddBA Req from %pM on tid %u\n",
+ sta->sta.addr, tid);
+ }
/* delete existing Rx BA session on the same tid */
___ieee80211_stop_rx_ba_session(sta, tid, WLAN_BACK_RECIPIENT,
@@ -362,9 +374,11 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
if (ieee80211_hw_check(&local->hw, SUPPORTS_REORDERING_BUFFER)) {
ret = drv_ampdu_action(local, sta->sdata, ¶ms);
- ht_dbg(sta->sdata,
- "Rx A-MPDU request on %pM tid %d result %d\n",
- sta->sta.addr, tid, ret);
+ if (sta->sdata) {
+ ht_dbg(sta->sdata,
+ "Rx A-MPDU request on %pM tid %d result %d\n",
+ sta->sta.addr, tid, ret);
+ }
if (!ret)
status = WLAN_STATUS_SUCCESS;
goto end;
@@ -401,8 +415,10 @@ void ___ieee80211_start_rx_ba_session(struct sta_info *sta,
__skb_queue_head_init(&tid_agg_rx->reorder_buf[i]);
ret = drv_ampdu_action(local, sta->sdata, ¶ms);
- ht_dbg(sta->sdata, "Rx A-MPDU request on %pM tid %d result %d\n",
- sta->sta.addr, tid, ret);
+ if (sta->sdata) {
+ ht_dbg(sta->sdata, "Rx A-MPDU request on %pM tid %d result %d\n",
+ sta->sta.addr, tid, ret);
+ }
if (ret) {
kfree(tid_agg_rx->reorder_buf);
kfree(tid_agg_rx->reorder_time);
diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
index f9514bacbd4a..03b31b6e7ac7 100644
--- a/net/mac80211/agg-tx.c
+++ b/net/mac80211/agg-tx.c
@@ -368,8 +368,10 @@ int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
spin_unlock_bh(&sta->lock);
- ht_dbg(sta->sdata, "Tx BA session stop requested for %pM tid %u\n",
- sta->sta.addr, tid);
+ if (sta->sdata) {
+ ht_dbg(sta->sdata, "Tx BA session stop requested for %pM tid %u\n",
+ sta->sta.addr, tid);
+ }
del_timer_sync(&tid_tx->addba_resp_timer);
del_timer_sync(&tid_tx->session_timer);
@@ -776,7 +778,12 @@ void ieee80211_start_tx_ba_cb(struct sta_info *sta, int tid,
struct tid_ampdu_tx *tid_tx)
{
struct ieee80211_sub_if_data *sdata = sta->sdata;
- struct ieee80211_local *local = sdata->local;
+ struct ieee80211_local *local;
+
+ if (!sdata)
+ return;
+
+ local = sdata->local;
if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
return;
@@ -902,6 +909,9 @@ void ieee80211_stop_tx_ba_cb(struct sta_info *sta, int tid,
bool send_delba = false;
bool start_txq = false;
+ if (!sdata)
+ return;
+
ht_dbg(sdata, "Stopping Tx BA session for %pM tid %d\n",
sta->sta.addr, tid);
--
2.34.1
On Tue, Mar 21, 2023 at 05:31:22PM +0800, Jia-Ju Bai wrote:
> In a previous commit 69403bad97aa ("wifi: mac80211: sdata can be NULL
> during AMPDU start"), sta->sdata can be NULL, and thus it should be
> checked before being used.
>
> However, in the same call stack, sta->sdata is also used in the
> following functions:
>
> ieee80211_ba_session_work()
> ___ieee80211_stop_rx_ba_session(sta)
> ht_dbg(sta->sdata, ...); -> No check
> sdata_info(sta->sdata, ...); -> No check
> ieee80211_send_delba(sta->sdata, ...) -> No check
> ___ieee80211_start_rx_ba_session(sta)
> ht_dbg(sta->sdata, ...); -> No check
> ht_dbg_ratelimited(sta->sdata, ...); -> No check
> ieee80211_tx_ba_session_handle_start(sta)
> sdata = sta->sdata; if (!sdata) -> Add check by previous commit
> ___ieee80211_stop_tx_ba_session(sdata)
> ht_dbg(sta->sdata, ...); -> No check
> ieee80211_start_tx_ba_cb(sdata)
> sdata = sta->sdata; local = sdata->local -> No check
> ieee80211_stop_tx_ba_cb(sdata)
> ht_dbg(sta->sdata, ...); -> No check
>
> Thus, to avoid possible null-pointer dereferences, the related checks
> should be added.
>
> These bugs are reported by a static analysis tool implemented by myself,
> and they are found by extending a known bug fixed in the previous commit.
> Thus, they could be theoretical bugs.
>
> Signed-off-by: Jia-Ju Bai <[email protected]>
> ---
> v2:
> * Fix an error reported by checkpatch.pl, and make the bug finding
> process more clear in the description. Thanks for Simon's advice.
> ---
> net/mac80211/agg-rx.c | 68 ++++++++++++++++++++++++++-----------------
> net/mac80211/agg-tx.c | 16 ++++++++--
> 2 files changed, 55 insertions(+), 29 deletions(-)
>
> diff --git a/net/mac80211/agg-rx.c b/net/mac80211/agg-rx.c
> index c6fa53230450..6616970785a2 100644
> --- a/net/mac80211/agg-rx.c
> +++ b/net/mac80211/agg-rx.c
> @@ -80,19 +80,21 @@ void ___ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
> RCU_INIT_POINTER(sta->ampdu_mlme.tid_rx[tid], NULL);
> __clear_bit(tid, sta->ampdu_mlme.agg_session_valid);
>
> - ht_dbg(sta->sdata,
> - "Rx BA session stop requested for %pM tid %u %s reason: %d\n", > - sta->sta.addr, tid,
> - initiator == WLAN_BACK_RECIPIENT ? "recipient" : "initiator",
> - (int)reason);
> + if (sta->sdata) {
> + ht_dbg(sta->sdata,
> + "Rx BA session stop requested for %pM tid %u %s reason: %d\n",
> + sta->sta.addr, tid,
> + initiator == WLAN_BACK_RECIPIENT ? "recipient" : "initiator",
> + (int)reason);
> + }
The first line of the body of ___ieee80211_stop_rx_ba_session() is:
struct ieee80211_local *local = sta->sdata->local;
So a NULL pointer dereference will have occurred before
the checks this change adds to that function.
>
> - if (drv_ampdu_action(local, sta->sdata, ¶ms))
> + if (sta->sdata && drv_ampdu_action(local, sta->sdata, ¶ms))
> sdata_info(sta->sdata,
> "HW problem - can not stop rx aggregation for %pM tid %d\n",
> sta->sta.addr, tid);
>
...
> diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
> index f9514bacbd4a..03b31b6e7ac7 100644
> --- a/net/mac80211/agg-tx.c
> +++ b/net/mac80211/agg-tx.c
> @@ -368,8 +368,10 @@ int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
>
> spin_unlock_bh(&sta->lock);
>
> - ht_dbg(sta->sdata, "Tx BA session stop requested for %pM tid %u\n",
> - sta->sta.addr, tid);
> + if (sta->sdata) {
> + ht_dbg(sta->sdata, "Tx BA session stop requested for %pM tid %u\n",
> + sta->sta.addr, tid);
> + }
This seems clean :)
> del_timer_sync(&tid_tx->addba_resp_timer);
> del_timer_sync(&tid_tx->session_timer);
> @@ -776,7 +778,12 @@ void ieee80211_start_tx_ba_cb(struct sta_info *sta, int tid,
> struct tid_ampdu_tx *tid_tx)
> {
> struct ieee80211_sub_if_data *sdata = sta->sdata;
> - struct ieee80211_local *local = sdata->local;
> + struct ieee80211_local *local;
> +
> + if (!sdata)
> + return;
I'm not sure that silently ignoring non-existent sdata is the right approach.
Perhaps a WARN_ON or WARN_ONCE is appropriate?
> +
> + local = sdata->local;
>
> if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
> return;
> @@ -902,6 +909,9 @@ void ieee80211_stop_tx_ba_cb(struct sta_info *sta, int tid,
> bool send_delba = false;
> bool start_txq = false;
>
> + if (!sdata)
> + return;
> +
Ditto.
> ht_dbg(sdata, "Stopping Tx BA session for %pM tid %d\n",
> sta->sta.addr, tid);
>
Hi Simon,
Thanks for your reply, and sorry for the delay.
On 2023/3/26 23:05, Simon Horman wrote:
> On Tue, Mar 21, 2023 at 05:31:22PM +0800, Jia-Ju Bai wrote:
>> In a previous commit 69403bad97aa ("wifi: mac80211: sdata can be NULL
>> during AMPDU start"), sta->sdata can be NULL, and thus it should be
>> checked before being used.
>>
>> However, in the same call stack, sta->sdata is also used in the
>> following functions:
>>
>> ieee80211_ba_session_work()
>> ___ieee80211_stop_rx_ba_session(sta)
>> ht_dbg(sta->sdata, ...); -> No check
>> sdata_info(sta->sdata, ...); -> No check
>> ieee80211_send_delba(sta->sdata, ...) -> No check
>> ___ieee80211_start_rx_ba_session(sta)
>> ht_dbg(sta->sdata, ...); -> No check
>> ht_dbg_ratelimited(sta->sdata, ...); -> No check
>> ieee80211_tx_ba_session_handle_start(sta)
>> sdata = sta->sdata; if (!sdata) -> Add check by previous commit
>> ___ieee80211_stop_tx_ba_session(sdata)
>> ht_dbg(sta->sdata, ...); -> No check
>> ieee80211_start_tx_ba_cb(sdata)
>> sdata = sta->sdata; local = sdata->local -> No check
>> ieee80211_stop_tx_ba_cb(sdata)
>> ht_dbg(sta->sdata, ...); -> No check
>>
>> Thus, to avoid possible null-pointer dereferences, the related checks
>> should be added.
>>
>> These bugs are reported by a static analysis tool implemented by myself,
>> and they are found by extending a known bug fixed in the previous commit.
>> Thus, they could be theoretical bugs.
>>
>> Signed-off-by: Jia-Ju Bai <[email protected]>
>> ---
>> v2:
>> * Fix an error reported by checkpatch.pl, and make the bug finding
>> process more clear in the description. Thanks for Simon's advice.
>> ---
>> net/mac80211/agg-rx.c | 68 ++++++++++++++++++++++++++-----------------
>> net/mac80211/agg-tx.c | 16 ++++++++--
>> 2 files changed, 55 insertions(+), 29 deletions(-)
>>
>> diff --git a/net/mac80211/agg-rx.c b/net/mac80211/agg-rx.c
>> index c6fa53230450..6616970785a2 100644
>> --- a/net/mac80211/agg-rx.c
>> +++ b/net/mac80211/agg-rx.c
>> @@ -80,19 +80,21 @@ void ___ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid,
>> RCU_INIT_POINTER(sta->ampdu_mlme.tid_rx[tid], NULL);
>> __clear_bit(tid, sta->ampdu_mlme.agg_session_valid);
>>
>> - ht_dbg(sta->sdata,
>> - "Rx BA session stop requested for %pM tid %u %s reason: %d\n", > - sta->sta.addr, tid,
>> - initiator == WLAN_BACK_RECIPIENT ? "recipient" : "initiator",
>> - (int)reason);
>> + if (sta->sdata) {
>> + ht_dbg(sta->sdata,
>> + "Rx BA session stop requested for %pM tid %u %s reason: %d\n",
>> + sta->sta.addr, tid,
>> + initiator == WLAN_BACK_RECIPIENT ? "recipient" : "initiator",
>> + (int)reason);
>> + }
> The first line of the body of ___ieee80211_stop_rx_ba_session() is:
>
> struct ieee80211_local *local = sta->sdata->local;
>
> So a NULL pointer dereference will have occurred before
> the checks this change adds to that function.
I checked the source code again (including the latest version 6.3-rc5).
The first line of the body of ___ieee80211_stop_rx_ba_session() is:
struct ieee80211_local *local = sta->local;
Thus, there is no dereference of sta->sdata.
In a different function, namely ___ieee80211_start_rx_ba_session(), the
first line is:
struct ieee80211_local *local = sta->sdata->local;
Thus, there should be a NULL check for sta->sdata in this function.
I will add this in my patch v3.
>
>
>>
>> - if (drv_ampdu_action(local, sta->sdata, ¶ms))
>> + if (sta->sdata && drv_ampdu_action(local, sta->sdata, ¶ms))
>> sdata_info(sta->sdata,
>> "HW problem - can not stop rx aggregation for %pM tid %d\n",
>> sta->sta.addr, tid);
>>
> ...
>
>> diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
>> index f9514bacbd4a..03b31b6e7ac7 100644
>> --- a/net/mac80211/agg-tx.c
>> +++ b/net/mac80211/agg-tx.c
>> @@ -368,8 +368,10 @@ int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
>>
>> spin_unlock_bh(&sta->lock);
>>
>> - ht_dbg(sta->sdata, "Tx BA session stop requested for %pM tid %u\n",
>> - sta->sta.addr, tid);
>> + if (sta->sdata) {
>> + ht_dbg(sta->sdata, "Tx BA session stop requested for %pM tid %u\n",
>> + sta->sta.addr, tid);
>> + }
> This seems clean :)
>
>> del_timer_sync(&tid_tx->addba_resp_timer);
>> del_timer_sync(&tid_tx->session_timer);
>> @@ -776,7 +778,12 @@ void ieee80211_start_tx_ba_cb(struct sta_info *sta, int tid,
>> struct tid_ampdu_tx *tid_tx)
>> {
>> struct ieee80211_sub_if_data *sdata = sta->sdata;
>> - struct ieee80211_local *local = sdata->local;
>> + struct ieee80211_local *local;
>> +
>> + if (!sdata)
>> + return;
> I'm not sure that silently ignoring non-existent sdata is the right approach.
> Perhaps a WARN_ON or WARN_ONCE is appropriate?
Okay, I will use WARN_ON in my patch v3.
>
>> +
>> + local = sdata->local;
>>
>> if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
>> return;
>> @@ -902,6 +909,9 @@ void ieee80211_stop_tx_ba_cb(struct sta_info *sta, int tid,
>> bool send_delba = false;
>> bool start_txq = false;
>>
>> + if (!sdata)
>> + return;
>> +
> Ditto.
Okay, I will use WARN_ON in my patch v3.
>
>> ht_dbg(sdata, "Stopping Tx BA session for %pM tid %d\n",
>> sta->sta.addr, tid);
>>
Best wishes,
Jia-Ju Bai