[PATCH v3] Bluetooth: hci_sync: Fix overwriting request callback

[PATCH v3] Bluetooth: hci_sync: Fix overwriting request callback

[Luiz Augusto von Dentz]

From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

In a few cases the stack may generate commands as responses to events
which would happen to overwrite the sent_cmd, so this attempts to store
the request in req_skb so even if sent_cmd is replaced with a new
command the pending request will remain in stored in req_skb.

Fixes: 6a98e3836fa2 ("Bluetooth: Add helper for serialized HCI command execution")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
---
 include/net/bluetooth/hci_core.h |  1 +
 net/bluetooth/hci_conn.c         |  2 +-
 net/bluetooth/hci_core.c         | 46 ++++++++++++++++++++++----------
 net/bluetooth/hci_event.c        | 18 ++++++-------
 net/bluetooth/hci_sync.c         | 21 ++++++++++++---
 5 files changed, 61 insertions(+), 27 deletions(-)

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index da6aa6549b81..56fb42df44a3 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -552,6 +552,7 @@ struct hci_dev {
 	__u32			req_status;
 	__u32			req_result;
 	struct sk_buff		*req_skb;
+	struct sk_buff		*req_rsp;
 
 	void			*smp_data;
 	void			*smp_bredr_data;
diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 54d4189c198a..3ad74f76983b 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -2918,7 +2918,7 @@ int hci_abort_conn(struct hci_conn *conn, u8 reason)
 		case HCI_EV_LE_CONN_COMPLETE:
 		case HCI_EV_LE_ENHANCED_CONN_COMPLETE:
 		case HCI_EVT_LE_CIS_ESTABLISHED:
-			hci_cmd_sync_cancel(hdev, -ECANCELED);
+			hci_cmd_sync_cancel(hdev, ECANCELED);
 			break;
 		}
 	/* Cancel connect attempt if still queued/pending */
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 34c8dca2069f..6ca4c0df9f9c 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1522,8 +1522,8 @@ static void hci_cmd_timeout(struct work_struct *work)
 	struct hci_dev *hdev = container_of(work, struct hci_dev,
 					    cmd_timer.work);
 
-	if (hdev->sent_cmd) {
-		u16 opcode = hci_skb_opcode(hdev->sent_cmd);
+	if (hdev->req_skb) {
+		u16 opcode = hci_skb_opcode(hdev->req_skb);
 
 		bt_dev_err(hdev, "command 0x%4.4x tx timeout", opcode);
 
@@ -2828,6 +2828,7 @@ void hci_release_dev(struct hci_dev *hdev)
 	ida_destroy(&hdev->unset_handle_ida);
 	ida_free(&hci_index_ida, hdev->id);
 	kfree_skb(hdev->sent_cmd);
+	kfree_skb(hdev->req_skb);
 	kfree_skb(hdev->recv_event);
 	kfree(hdev);
 }
@@ -3157,21 +3158,33 @@ int __hci_cmd_send(struct hci_dev *hdev, u16 opcode, u32 plen,
 EXPORT_SYMBOL(__hci_cmd_send);
 
 /* Get data from the previously sent command */
-void *hci_sent_cmd_data(struct hci_dev *hdev, __u16 opcode)
+static void *hci_cmd_data(struct sk_buff *skb, __u16 opcode)
 {
 	struct hci_command_hdr *hdr;
 
-	if (!hdev->sent_cmd)
+	if (!skb || skb->len < HCI_COMMAND_HDR_SIZE)
 		return NULL;
 
-	hdr = (void *) hdev->sent_cmd->data;
+	hdr = (void *)skb->data;
 
 	if (hdr->opcode != cpu_to_le16(opcode))
 		return NULL;
 
-	BT_DBG("%s opcode 0x%4.4x", hdev->name, opcode);
+	return skb->data + HCI_COMMAND_HDR_SIZE;
+}
 
-	return hdev->sent_cmd->data + HCI_COMMAND_HDR_SIZE;
+/* Get data from the previously sent command */
+void *hci_sent_cmd_data(struct hci_dev *hdev, __u16 opcode)
+{
+	void *data;
+
+	/* Check if opcode matches last sent command */
+	data = hci_cmd_data(hdev->sent_cmd, opcode);
+	if (!data)
+		/* Check if opcode matches last request */
+		data = hci_cmd_data(hdev->req_skb, opcode);
+
+	return data;
 }
 
 /* Get data from last received event */
@@ -4072,17 +4085,19 @@ void hci_req_cmd_complete(struct hci_dev *hdev, u16 opcode, u8 status,
 	if (!status && !hci_req_is_complete(hdev))
 		return;
 
+	skb = hdev->req_skb;
+
 	/* If this was the last command in a request the complete
-	 * callback would be found in hdev->sent_cmd instead of the
+	 * callback would be found in hdev->req_skb instead of the
 	 * command queue (hdev->cmd_q).
 	 */
-	if (bt_cb(hdev->sent_cmd)->hci.req_flags & HCI_REQ_SKB) {
-		*req_complete_skb = bt_cb(hdev->sent_cmd)->hci.req_complete_skb;
+	if (skb && bt_cb(skb)->hci.req_flags & HCI_REQ_SKB) {
+		*req_complete_skb = bt_cb(skb)->hci.req_complete_skb;
 		return;
 	}
 
-	if (bt_cb(hdev->sent_cmd)->hci.req_complete) {
-		*req_complete = bt_cb(hdev->sent_cmd)->hci.req_complete;
+	if (skb && bt_cb(skb)->hci.req_complete) {
+		*req_complete = bt_cb(skb)->hci.req_complete;
 		return;
 	}
 
@@ -4199,8 +4214,11 @@ static void hci_send_cmd_sync(struct hci_dev *hdev, struct sk_buff *skb)
 		return;
 	}
 
-	if (hci_req_status_pend(hdev))
-		hci_dev_set_flag(hdev, HCI_CMD_PENDING);
+	if (hci_req_status_pend(hdev) &&
+	    !hci_dev_test_and_set_flag(hdev, HCI_CMD_PENDING)) {
+		kfree_skb(hdev->req_skb);
+		hdev->req_skb = skb_clone(skb, GFP_KERNEL);
+	}
 
 	atomic_dec(&hdev->cmd_cnt);
 }
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 6071a1226e1b..bffd2c7ff608 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -4368,7 +4368,7 @@ static void hci_cmd_status_evt(struct hci_dev *hdev, void *data,
 	 * (since for this kind of commands there will not be a command
 	 * complete event).
 	 */
-	if (ev->status || (hdev->sent_cmd && !hci_skb_event(hdev->sent_cmd))) {
+	if (ev->status || (hdev->req_skb && !hci_skb_event(hdev->req_skb))) {
 		hci_req_cmd_complete(hdev, *opcode, ev->status, req_complete,
 				     req_complete_skb);
 		if (hci_dev_test_flag(hdev, HCI_CMD_PENDING)) {
@@ -7170,10 +7170,10 @@ static void hci_le_meta_evt(struct hci_dev *hdev, void *data,
 	bt_dev_dbg(hdev, "subevent 0x%2.2x", ev->subevent);
 
 	/* Only match event if command OGF is for LE */
-	if (hdev->sent_cmd &&
-	    hci_opcode_ogf(hci_skb_opcode(hdev->sent_cmd)) == 0x08 &&
-	    hci_skb_event(hdev->sent_cmd) == ev->subevent) {
-		*opcode = hci_skb_opcode(hdev->sent_cmd);
+	if (hdev->req_skb &&
+	    hci_opcode_ogf(hci_skb_opcode(hdev->req_skb)) == 0x08 &&
+	    hci_skb_event(hdev->req_skb) == ev->subevent) {
+		*opcode = hci_skb_opcode(hdev->req_skb);
 		hci_req_cmd_complete(hdev, *opcode, 0x00, req_complete,
 				     req_complete_skb);
 	}
@@ -7541,10 +7541,10 @@ void hci_event_packet(struct hci_dev *hdev, struct sk_buff *skb)
 	}
 
 	/* Only match event if command OGF is not for LE */
-	if (hdev->sent_cmd &&
-	    hci_opcode_ogf(hci_skb_opcode(hdev->sent_cmd)) != 0x08 &&
-	    hci_skb_event(hdev->sent_cmd) == event) {
-		hci_req_cmd_complete(hdev, hci_skb_opcode(hdev->sent_cmd),
+	if (hdev->req_skb &&
+	    hci_opcode_ogf(hci_skb_opcode(hdev->req_skb)) != 0x08 &&
+	    hci_skb_event(hdev->req_skb) == event) {
+		hci_req_cmd_complete(hdev, hci_skb_opcode(hdev->req_skb),
 				     status, &req_complete, &req_complete_skb);
 		req_evt = event;
 	}
diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
index 10aa59da735b..8a3d0d1f7871 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c
@@ -32,6 +32,10 @@ static void hci_cmd_sync_complete(struct hci_dev *hdev, u8 result, u16 opcode,
 	hdev->req_result = result;
 	hdev->req_status = HCI_REQ_DONE;
 
+	/* Free the request command so it is not used as response */
+	kfree_skb(hdev->req_skb);
+	hdev->req_skb = NULL;
+
 	if (skb) {
 		struct sock *sk = hci_skb_sk(skb);
 
@@ -39,7 +43,7 @@ static void hci_cmd_sync_complete(struct hci_dev *hdev, u8 result, u16 opcode,
 		if (sk)
 			sock_put(sk);
 
-		hdev->req_skb = skb_get(skb);
+		hdev->req_rsp = skb_get(skb);
 	}
 
 	wake_up_interruptible(&hdev->req_wait_q);
@@ -187,8 +191,8 @@ struct sk_buff *__hci_cmd_sync_sk(struct hci_dev *hdev, u16 opcode, u32 plen,
 
 	hdev->req_status = 0;
 	hdev->req_result = 0;
-	skb = hdev->req_skb;
-	hdev->req_skb = NULL;
+	skb = hdev->req_rsp;
+	hdev->req_rsp = NULL;
 
 	bt_dev_dbg(hdev, "end: err %d", err);
 
@@ -5021,6 +5025,11 @@ int hci_dev_open_sync(struct hci_dev *hdev)
 			hdev->sent_cmd = NULL;
 		}
 
+		if (hdev->req_skb) {
+			kfree_skb(hdev->req_skb);
+			hdev->req_skb = NULL;
+		}
+
 		clear_bit(HCI_RUNNING, &hdev->flags);
 		hci_sock_dev_event(hdev, HCI_DEV_CLOSE);
 
@@ -5181,6 +5190,12 @@ int hci_dev_close_sync(struct hci_dev *hdev)
 		hdev->sent_cmd = NULL;
 	}
 
+	/* Drop last request */
+	if (hdev->req_skb) {
+		kfree_skb(hdev->req_skb);
+		hdev->req_skb = NULL;
+	}
+
 	clear_bit(HCI_RUNNING, &hdev->flags);
 	hci_sock_dev_event(hdev, HCI_DEV_CLOSE);
 
-- 
2.43.0

RE: [v3] Bluetooth: hci_sync: Fix overwriting request callback

[bluez.test.bot]

[-- Attachment #1: Type: text/plain, Size: 1824 bytes --]

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=830444

---Test result---

Test Summary:
CheckPatch                    PASS      1.26 seconds
GitLint                       PASS      0.22 seconds
SubjectPrefix                 PASS      0.07 seconds
BuildKernel                   PASS      27.56 seconds
CheckAllWarning               PASS      30.30 seconds
CheckSparse                   WARNING   35.87 seconds
CheckSmatch                   WARNING   97.82 seconds
BuildKernel32                 PASS      26.81 seconds
TestRunnerSetup               PASS      498.43 seconds
TestRunner_l2cap-tester       PASS      18.17 seconds
TestRunner_iso-tester         PASS      32.34 seconds
TestRunner_bnep-tester        PASS      4.76 seconds
TestRunner_mgmt-tester        PASS      112.17 seconds
TestRunner_rfcomm-tester      PASS      7.30 seconds
TestRunner_sco-tester         PASS      14.96 seconds
TestRunner_ioctl-tester       PASS      7.79 seconds
TestRunner_mesh-tester        PASS      5.85 seconds
TestRunner_smp-tester         PASS      6.85 seconds
TestRunner_userchan-tester    PASS      4.90 seconds
IncrementalBuild              PASS      25.51 seconds

Details
##############################
Test: CheckSparse - WARNING
Desc: Run sparse tool with linux kernel
Output:
net/bluetooth/hci_event.c: note: in included file (through include/net/bluetooth/hci_core.h):
##############################
Test: CheckSmatch - WARNING
Desc: Run smatch tool with source
Output:
net/bluetooth/hci_event.c: note: in included file (through include/net/bluetooth/hci_core.h):


---
Regards,
Linux Bluetooth

Re: [PATCH v3] Bluetooth: hci_sync: Fix overwriting request callback

[patchwork-bot+bluetooth]

Hello:

This patch was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>:

On Tue, 27 Feb 2024 17:04:28 -0500 you wrote:
> From: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
> 
> In a few cases the stack may generate commands as responses to events
> which would happen to overwrite the sent_cmd, so this attempts to store
> the request in req_skb so even if sent_cmd is replaced with a new
> command the pending request will remain in stored in req_skb.
> 
> [...]

Here is the summary with links:
  - [v3] Bluetooth: hci_sync: Fix overwriting request callback
    https://git.kernel.org/bluetooth/bluetooth-next/c/afe04d6e61dd

You are awesome, thank you!
-- 
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