2024-02-20 16:43:53

by Luiz Augusto von Dentz

[permalink] [raw]
Subject: [PATCH v2] Bluetooth: hci_sync: Fix overwriting request callback

From: Luiz Augusto von Dentz <[email protected]>

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.

Signed-off-by: Luiz Augusto von Dentz <[email protected]>
---
net/bluetooth/hci_conn.c | 2 +-
net/bluetooth/hci_core.c | 46 +++++++++++++++++++++++++++------------
net/bluetooth/hci_event.c | 18 +++++++--------
net/bluetooth/hci_sync.c | 15 +++++++++++++
4 files changed, 57 insertions(+), 24 deletions(-)

diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c
index 21e0b4064d05..1acc75a49bb0 100644
--- a/net/bluetooth/hci_conn.c
+++ b/net/bluetooth/hci_conn.c
@@ -2893,7 +2893,7 @@ int hci_abort_conn(struct hci_conn *conn, u8 reason)
* connection can be in BT_CONNECT at time.
*/
if (conn->state == BT_CONNECT && hdev->req_status == HCI_REQ_PEND) {
- switch (hci_skb_event(hdev->sent_cmd)) {
+ switch (hci_skb_event(hdev->req_skb)) {
case HCI_EV_CONN_COMPLETE:
case HCI_EV_LE_CONN_COMPLETE:
case HCI_EV_LE_ENHANCED_CONN_COMPLETE:
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 4a28aef2f01f..7306020ccda3 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);

@@ -4952,6 +4956,11 @@ 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);

@@ -5112,6 +5121,12 @@ 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



2024-02-20 19:10:56

by patchwork-bot+bluetooth

[permalink] [raw]
Subject: Re: [PATCH v2] Bluetooth: hci_sync: Fix overwriting request callback

Hello:

This patch was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <[email protected]>:

On Tue, 20 Feb 2024 11:31:41 -0500 you wrote:
> From: Luiz Augusto von Dentz <[email protected]>
>
> 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:
- [v2] Bluetooth: hci_sync: Fix overwriting request callback
https://git.kernel.org/bluetooth/bluetooth-next/c/df90bef42e65

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