wifi: brcmfmac: fix crash while sending Action Frames in standalone AP Mode

commit 3776c685ebe5f43e9060af06872661de55e80b9a upstream.

Currently, whenever there is a need to transmit an Action frame,
the brcmfmac driver always uses the P2P vif to send the "actframe" IOVAR to
firmware. The P2P interfaces were available when wpa_supplicant is managing
the wlan interface.

However, the P2P interfaces are not created/initialized when only hostapd
is managing the wlan interface. And if hostapd receives an ANQP Query REQ
Action frame even from an un-associated STA, the brcmfmac driver tries
to use an uninitialized P2P vif pointer for sending the IOVAR to firmware.
This NULL pointer dereferencing triggers a driver crash.

 [ 1417.074538] Unable to handle kernel NULL pointer dereference at virtual
 address 0000000000000000
 [...]
 [ 1417.075188] Hardware name: Raspberry Pi 4 Model B Rev 1.5 (DT)
 [...]
 [ 1417.075653] Call trace:
 [ 1417.075662]  brcmf_p2p_send_action_frame+0x23c/0xc58 [brcmfmac]
 [ 1417.075738]  brcmf_cfg80211_mgmt_tx+0x304/0x5c0 [brcmfmac]
 [ 1417.075810]  cfg80211_mlme_mgmt_tx+0x1b0/0x428 [cfg80211]
 [ 1417.076067]  nl80211_tx_mgmt+0x238/0x388 [cfg80211]
 [ 1417.076281]  genl_family_rcv_msg_doit+0xe0/0x158
 [ 1417.076302]  genl_rcv_msg+0x220/0x2a0
 [ 1417.076317]  netlink_rcv_skb+0x68/0x140
 [ 1417.076330]  genl_rcv+0x40/0x60
 [ 1417.076343]  netlink_unicast+0x330/0x3b8
 [ 1417.076357]  netlink_sendmsg+0x19c/0x3f8
 [ 1417.076370]  __sock_sendmsg+0x64/0xc0
 [ 1417.076391]  ____sys_sendmsg+0x268/0x2a0
 [ 1417.076408]  ___sys_sendmsg+0xb8/0x118
 [ 1417.076427]  __sys_sendmsg+0x90/0xf8
 [ 1417.076445]  __arm64_sys_sendmsg+0x2c/0x40
 [ 1417.076465]  invoke_syscall+0x50/0x120
 [ 1417.076486]  el0_svc_common.constprop.0+0x48/0xf0
 [ 1417.076506]  do_el0_svc+0x24/0x38
 [ 1417.076525]  el0_svc+0x30/0x100
 [ 1417.076548]  el0t_64_sync_handler+0x100/0x130
 [ 1417.076569]  el0t_64_sync+0x190/0x198
 [ 1417.076589] Code: f9401e80 aa1603e2 f9403be1 5280e483 (f9400000)

Fix this, by always using the vif corresponding to the wdev on which the
Action frame Transmission request was initiated by the userspace. This way,
even if P2P vif is not available, the IOVAR is sent to firmware on AP vif
and the ANQP Query RESP Action frame is transmitted without crashing the
driver.

Move init_completion() for "send_af_done" from brcmf_p2p_create_p2pdev()
to brcmf_p2p_attach(). Because the former function would not get executed
when only hostapd is managing wlan interface, and it is not safe to do
reinit_completion() later in brcmf_p2p_tx_action_frame(), without any prior
init_completion().

And in the brcmf_p2p_tx_action_frame() function, the condition check for
P2P Presence response frame is not needed, since the wpa_supplicant is
properly sending the P2P Presense Response frame on the P2P-GO vif instead
of the P2P-Device vif.

Cc: [email protected]
Fixes: 18e2f61 ("brcmfmac: P2P action frame tx")
Signed-off-by: Gokul Sivakumar <[email protected]>
Acked-by: Arend van Spriel <[email protected]>
Link: https://patch.msgid.link/[email protected]
[Cc stable]
Signed-off-by: Johannes Berg <[email protected]>

Author: gokulkumar-ifx

drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c

@@ -5643,8 +5643,7 @@ brcmf_cfg80211_mgmt_tx(struct wiphy *wiphy, struct wireless_dev *wdev,
 			  *cookie, le16_to_cpu(action_frame->len),
 			  le32_to_cpu(af_params->channel));
 
-		ack = brcmf_p2p_send_action_frame(cfg, cfg_to_ndev(cfg),
-						  af_params);
+		ack = brcmf_p2p_send_action_frame(vif->ifp, af_params);
 
 		cfg80211_mgmt_tx_status(wdev, *cookie, buf, len, ack,
 					GFP_KERNEL);

drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c

@@ -1533,6 +1533,7 @@ int brcmf_p2p_notify_action_tx_complete(struct brcmf_if *ifp,
 /**
  * brcmf_p2p_tx_action_frame() - send action frame over fil.
  *
+ * @ifp: interface to transmit on.
  * @p2p: p2p info struct for vif.
  * @af_params: action frame data/info.
  *
@@ -1542,12 +1543,11 @@ int brcmf_p2p_notify_action_tx_complete(struct brcmf_if *ifp,
  * The WLC_E_ACTION_FRAME_COMPLETE event will be received when the action
  * frame is transmitted.
  */
-static s32 brcmf_p2p_tx_action_frame(struct brcmf_p2p_info *p2p,
+static s32 brcmf_p2p_tx_action_frame(struct brcmf_if *ifp,
+				     struct brcmf_p2p_info *p2p,
 				     struct brcmf_fil_af_params_le *af_params)
 {
 	struct brcmf_pub *drvr = p2p->cfg->pub;
-	struct brcmf_cfg80211_vif *vif;
-	struct brcmf_p2p_action_frame *p2p_af;
 	s32 err = 0;
 
 	brcmf_dbg(TRACE, "Enter\n");
@@ -1556,14 +1556,7 @@ static s32 brcmf_p2p_tx_action_frame(struct brcmf_p2p_info *p2p,
 	clear_bit(BRCMF_P2P_STATUS_ACTION_TX_COMPLETED, &p2p->status);
 	clear_bit(BRCMF_P2P_STATUS_ACTION_TX_NOACK, &p2p->status);
 
-	/* check if it is a p2p_presence response */
-	p2p_af = (struct brcmf_p2p_action_frame *)af_params->action_frame.data;
-	if (p2p_af->subtype == P2P_AF_PRESENCE_RSP)
-		vif = p2p->bss_idx[P2PAPI_BSSCFG_CONNECTION].vif;
-	else
-		vif = p2p->bss_idx[P2PAPI_BSSCFG_DEVICE].vif;
-
-	err = brcmf_fil_bsscfg_data_set(vif->ifp, "actframe", af_params,
+	err = brcmf_fil_bsscfg_data_set(ifp, "actframe", af_params,
 					sizeof(*af_params));
 	if (err) {
 		bphy_err(drvr, " sending action frame has failed\n");
@@ -1715,16 +1708,14 @@ static bool brcmf_p2p_check_dwell_overflow(u32 requested_dwell,
 /**
  * brcmf_p2p_send_action_frame() - send action frame .
  *
- * @cfg: driver private data for cfg80211 interface.
- * @ndev: net device to transmit on.
+ * @ifp: interface to transmit on.
  * @af_params: configuration data for action frame.
  */
-bool brcmf_p2p_send_action_frame(struct brcmf_cfg80211_info *cfg,
-				 struct net_device *ndev,
+bool brcmf_p2p_send_action_frame(struct brcmf_if *ifp,
 				 struct brcmf_fil_af_params_le *af_params)
 {
+	struct brcmf_cfg80211_info *cfg = ifp->drvr->config;
 	struct brcmf_p2p_info *p2p = &cfg->p2p;
-	struct brcmf_if *ifp = netdev_priv(ndev);
 	struct brcmf_fil_action_frame_le *action_frame;
 	struct brcmf_config_af_params config_af_params;
 	struct afx_hdl *afx_hdl = &p2p->afx_hdl;
@@ -1862,7 +1853,7 @@ bool brcmf_p2p_send_action_frame(struct brcmf_cfg80211_info *cfg,
 		if (af_params->channel)
 			msleep(P2P_AF_RETRY_DELAY_TIME);
 
-		ack = !brcmf_p2p_tx_action_frame(p2p, af_params);
+		ack = !brcmf_p2p_tx_action_frame(ifp, p2p, af_params);
 		tx_retry++;
 		dwell_overflow = brcmf_p2p_check_dwell_overflow(requested_dwell,
 								dwell_jiffies);
@@ -2222,7 +2213,6 @@ static struct wireless_dev *brcmf_p2p_create_p2pdev(struct brcmf_p2p_info *p2p,
 
 	WARN_ON(p2p_ifp->bsscfgidx != bsscfgidx);
 
-	init_completion(&p2p->send_af_done);
 	INIT_WORK(&p2p->afx_hdl.afx_work, brcmf_p2p_afx_handler);
 	init_completion(&p2p->afx_hdl.act_frm_scan);
 	init_completion(&p2p->wait_next_af);
@@ -2518,6 +2508,8 @@ s32 brcmf_p2p_attach(struct brcmf_cfg80211_info *cfg, bool p2pdev_forced)
 	pri_ifp = brcmf_get_ifp(cfg->pub, 0);
 	p2p->bss_idx[P2PAPI_BSSCFG_PRIMARY].vif = pri_ifp->vif;
 
+	init_completion(&p2p->send_af_done);
+
 	if (p2pdev_forced) {
 		err_ptr = brcmf_p2p_create_p2pdev(p2p, NULL, NULL);
 		if (IS_ERR(err_ptr)) {

drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.h

@@ -168,8 +168,7 @@ int brcmf_p2p_notify_action_frame_rx(struct brcmf_if *ifp,
 int brcmf_p2p_notify_action_tx_complete(struct brcmf_if *ifp,
 					const struct brcmf_event_msg *e,
 					void *data);
-bool brcmf_p2p_send_action_frame(struct brcmf_cfg80211_info *cfg,
-				 struct net_device *ndev,
+bool brcmf_p2p_send_action_frame(struct brcmf_if *ifp,
 				 struct brcmf_fil_af_params_le *af_params);
 bool brcmf_p2p_scan_finding_common_channel(struct brcmf_cfg80211_info *cfg,
 					   struct brcmf_bss_info_le *bi);