From a5f7a5bb3b7f28ba7e4fa246775b29a0e5537255 Mon Sep 17 00:00:00 2001 From: Jinke Han Date: Tue, 8 Sep 2026 15:37:42 +0800 Subject: x86/kprobes: Fix crash when probing CS CALL instructions When using eBPF to probe CS CALL instructions within a function, a crash can be triggered. The eBPF tool probes offset 257 of the __hrtimer_run_queues() function: <__hrtimer_run_queues+249>: nopl 0x0(%rax,%rax,1) <__hrtimer_run_queues+254>: mov %r14,%rdi <__hrtimer_run_queues+257>: cs call <__x86_indirect_thunk_r12> <__hrtimer_run_queues+263>: mov %eax,%r12d <__hrtimer_run_queues+266>: xchg %ax,%ax <__hrtimer_run_queues+268>: mov %r13,%rdi Which triggers this crash: BUG: unable to handle page fault for address: 00000000000f41c9 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP NOPTI CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P RIP: 0010:__hrtimer_run_queues+0x106/0x230 Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is at the 6th byte of the above CS CALL instruction. Since the CS CALL instruction occupies 6 bytes, the exception occurred in the middle of that call instruction. The root cause is that when using eBPF tools to probe in the middle of a function, a kprobe with INT3 is used as the underlying implementation. During single-step emulation of the original CALL instruction, int3_emulate_call() assumes that the probed CALL instruction is 5 bytes long. However, the actual CS-prefixed CALL instruction occupies 6 bytes, so it constructs an incorrect exception return address. When the CPU returns from the kprobe handler, the next instruction to be executed is at the address of the last byte of that CS CALL instruction. Coincidentally, starting from that address, the CPU fetches and decodes a completely different instruction, which ultimately triggers a kernel crash. Fix the issue by using the actual instruction length obtained from the instruction decoder when constructing the exception return address, rather than relying on the hardcoded CALL_INSN_SIZE macro. [ mingo: Refined the changelog ] Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step") Suggested-by: Masami Hiramatsu (Google) Signed-off-by: Jinke Han Signed-off-by: Ingo Molnar Reviewed-by: Masami Hiramatsu (Google) Acked-by: Yafang Shao Acked-by: Borislav Petkov Cc: Peter Zijlstra Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000 --- drivers/bluetooth/bfusb.c | 755 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 755 insertions(+) create mode 100644 drivers/bluetooth/bfusb.c (limited to 'drivers/bluetooth/bfusb.c') diff --git a/drivers/bluetooth/bfusb.c b/drivers/bluetooth/bfusb.c new file mode 100644 index 000000000..d31d79763 --- /dev/null +++ b/drivers/bluetooth/bfusb.c @@ -0,0 +1,755 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * + * AVM BlueFRITZ! USB driver + * + * Copyright (C) 2003-2006 Marcel Holtmann + */ + +#include + +#include +#include +#include +#include +#include +#include + +#include +#include + +#include + +#include +#include + +#define VERSION "1.2" + +static struct usb_driver bfusb_driver; + +static const struct usb_device_id bfusb_table[] = { + /* AVM BlueFRITZ! USB */ + { USB_DEVICE(0x057c, 0x2200) }, + + { } /* Terminating entry */ +}; + +MODULE_DEVICE_TABLE(usb, bfusb_table); + +#define BFUSB_MAX_BLOCK_SIZE 256 + +#define BFUSB_BLOCK_TIMEOUT 3000 + +#define BFUSB_TX_PROCESS 1 +#define BFUSB_TX_WAKEUP 2 + +#define BFUSB_MAX_BULK_TX 2 +#define BFUSB_MAX_BULK_RX 2 + +struct bfusb_data { + struct hci_dev *hdev; + + unsigned long state; + + struct usb_device *udev; + + unsigned int bulk_in_ep; + unsigned int bulk_out_ep; + unsigned int bulk_pkt_size; + + rwlock_t lock; + + struct sk_buff_head transmit_q; + + struct sk_buff *reassembly; + + atomic_t pending_tx; + struct sk_buff_head pending_q; + struct sk_buff_head completed_q; +}; + +struct bfusb_data_scb { + struct urb *urb; +}; + +static void bfusb_tx_complete(struct urb *urb); +static void bfusb_rx_complete(struct urb *urb); + +static struct urb *bfusb_get_completed(struct bfusb_data *data) +{ + struct sk_buff *skb; + struct urb *urb = NULL; + + BT_DBG("bfusb %p", data); + + skb = skb_dequeue(&data->completed_q); + if (skb) { + urb = ((struct bfusb_data_scb *) skb->cb)->urb; + kfree_skb(skb); + } + + return urb; +} + +static void bfusb_unlink_urbs(struct bfusb_data *data) +{ + struct sk_buff *skb; + struct urb *urb; + + BT_DBG("bfusb %p", data); + + while ((skb = skb_dequeue(&data->pending_q))) { + urb = ((struct bfusb_data_scb *) skb->cb)->urb; + usb_kill_urb(urb); + skb_queue_tail(&data->completed_q, skb); + } + + while ((urb = bfusb_get_completed(data))) + usb_free_urb(urb); +} + +static int bfusb_send_bulk(struct bfusb_data *data, struct sk_buff *skb) +{ + struct bfusb_data_scb *scb = (void *) skb->cb; + struct urb *urb = bfusb_get_completed(data); + int err, pipe; + + BT_DBG("bfusb %p skb %p len %d", data, skb, skb->len); + + if (!urb) { + urb = usb_alloc_urb(0, GFP_ATOMIC); + if (!urb) + return -ENOMEM; + } + + pipe = usb_sndbulkpipe(data->udev, data->bulk_out_ep); + + usb_fill_bulk_urb(urb, data->udev, pipe, skb->data, skb->len, + bfusb_tx_complete, skb); + + scb->urb = urb; + + skb_queue_tail(&data->pending_q, skb); + + err = usb_submit_urb(urb, GFP_ATOMIC); + if (err) { + bt_dev_err(data->hdev, "bulk tx submit failed urb %p err %d", + urb, err); + skb_unlink(skb, &data->pending_q); + usb_free_urb(urb); + } else + atomic_inc(&data->pending_tx); + + return err; +} + +static void bfusb_tx_wakeup(struct bfusb_data *data) +{ + struct sk_buff *skb; + + BT_DBG("bfusb %p", data); + + if (test_and_set_bit(BFUSB_TX_PROCESS, &data->state)) { + set_bit(BFUSB_TX_WAKEUP, &data->state); + return; + } + + do { + clear_bit(BFUSB_TX_WAKEUP, &data->state); + + while ((atomic_read(&data->pending_tx) < BFUSB_MAX_BULK_TX) && + (skb = skb_dequeue(&data->transmit_q))) { + if (bfusb_send_bulk(data, skb) < 0) { + skb_queue_head(&data->transmit_q, skb); + break; + } + } + + } while (test_bit(BFUSB_TX_WAKEUP, &data->state)); + + clear_bit(BFUSB_TX_PROCESS, &data->state); +} + +static void bfusb_tx_complete(struct urb *urb) +{ + struct sk_buff *skb = (struct sk_buff *) urb->context; + struct bfusb_data *data = (struct bfusb_data *) skb->dev; + + BT_DBG("bfusb %p urb %p skb %p len %d", data, urb, skb, skb->len); + + atomic_dec(&data->pending_tx); + + if (!test_bit(HCI_RUNNING, &data->hdev->flags)) + return; + + if (!urb->status) + data->hdev->stat.byte_tx += skb->len; + else + data->hdev->stat.err_tx++; + + read_lock(&data->lock); + + skb_unlink(skb, &data->pending_q); + skb_queue_tail(&data->completed_q, skb); + + bfusb_tx_wakeup(data); + + read_unlock(&data->lock); +} + + +static int bfusb_rx_submit(struct bfusb_data *data, struct urb *urb) +{ + struct bfusb_data_scb *scb; + struct sk_buff *skb; + int err, pipe, size = HCI_MAX_FRAME_SIZE + 32; + + BT_DBG("bfusb %p urb %p", data, urb); + + if (!urb) { + urb = usb_alloc_urb(0, GFP_ATOMIC); + if (!urb) + return -ENOMEM; + } + + skb = bt_skb_alloc(size, GFP_ATOMIC); + if (!skb) { + usb_free_urb(urb); + return -ENOMEM; + } + + skb->dev = (void *) data; + + scb = (struct bfusb_data_scb *) skb->cb; + scb->urb = urb; + + pipe = usb_rcvbulkpipe(data->udev, data->bulk_in_ep); + + usb_fill_bulk_urb(urb, data->udev, pipe, skb->data, size, + bfusb_rx_complete, skb); + + skb_queue_tail(&data->pending_q, skb); + + err = usb_submit_urb(urb, GFP_ATOMIC); + if (err) { + bt_dev_err(data->hdev, "bulk rx submit failed urb %p err %d", + urb, err); + skb_unlink(skb, &data->pending_q); + kfree_skb(skb); + usb_free_urb(urb); + } + + return err; +} + +static inline int bfusb_recv_block(struct bfusb_data *data, int hdr, unsigned char *buf, int len) +{ + BT_DBG("bfusb %p hdr 0x%02x data %p len %d", data, hdr, buf, len); + + if (hdr & 0x10) { + bt_dev_err(data->hdev, "error in block"); + kfree_skb(data->reassembly); + data->reassembly = NULL; + return -EIO; + } + + if (hdr & 0x04) { + struct sk_buff *skb; + unsigned char pkt_type; + int pkt_len = 0; + + if (data->reassembly) { + bt_dev_err(data->hdev, "unexpected start block"); + kfree_skb(data->reassembly); + data->reassembly = NULL; + } + + if (len < 1) { + bt_dev_err(data->hdev, "no packet type found"); + return -EPROTO; + } + + pkt_type = *buf++; len--; + + switch (pkt_type) { + case HCI_EVENT_PKT: + if (len >= HCI_EVENT_HDR_SIZE) { + struct hci_event_hdr *hdr = (struct hci_event_hdr *) buf; + pkt_len = HCI_EVENT_HDR_SIZE + hdr->plen; + } else { + bt_dev_err(data->hdev, "event block is too short"); + return -EILSEQ; + } + break; + + case HCI_ACLDATA_PKT: + if (len >= HCI_ACL_HDR_SIZE) { + struct hci_acl_hdr *hdr = (struct hci_acl_hdr *) buf; + pkt_len = HCI_ACL_HDR_SIZE + __le16_to_cpu(hdr->dlen); + } else { + bt_dev_err(data->hdev, "data block is too short"); + return -EILSEQ; + } + break; + + case HCI_SCODATA_PKT: + if (len >= HCI_SCO_HDR_SIZE) { + struct hci_sco_hdr *hdr = (struct hci_sco_hdr *) buf; + pkt_len = HCI_SCO_HDR_SIZE + hdr->dlen; + } else { + bt_dev_err(data->hdev, "audio block is too short"); + return -EILSEQ; + } + break; + + default: + bt_dev_err(data->hdev, "unknown packet type 0x%02x", + pkt_type); + return -EILSEQ; + } + + skb = bt_skb_alloc(pkt_len, GFP_ATOMIC); + if (!skb) { + bt_dev_err(data->hdev, "no memory for the packet"); + return -ENOMEM; + } + + hci_skb_pkt_type(skb) = pkt_type; + + data->reassembly = skb; + } else { + if (!data->reassembly) { + bt_dev_err(data->hdev, "unexpected continuation block"); + return -EIO; + } + } + + if (len > skb_tailroom(data->reassembly)) { + bt_dev_err(data->hdev, "block exceeds packet length"); + kfree_skb(data->reassembly); + data->reassembly = NULL; + return -EILSEQ; + } + + if (len > 0) + skb_put_data(data->reassembly, buf, len); + + if (hdr & 0x08) { + hci_recv_frame(data->hdev, data->reassembly); + data->reassembly = NULL; + } + + return 0; +} + +static void bfusb_rx_complete(struct urb *urb) +{ + struct sk_buff *skb = (struct sk_buff *) urb->context; + struct bfusb_data *data = (struct bfusb_data *) skb->dev; + unsigned char *buf = urb->transfer_buffer; + int count = urb->actual_length; + int err, hdr, len; + + BT_DBG("bfusb %p urb %p skb %p len %d", data, urb, skb, skb->len); + + read_lock(&data->lock); + + if (!test_bit(HCI_RUNNING, &data->hdev->flags)) + goto unlock; + + if (urb->status || !count) + goto resubmit; + + data->hdev->stat.byte_rx += count; + + skb_put(skb, count); + + while (count) { + if (count < 2) { + bt_dev_err(data->hdev, "short block header"); + kfree_skb(data->reassembly); + data->reassembly = NULL; + break; + } + + hdr = buf[0] | (buf[1] << 8); + + if (hdr & 0x4000) { + len = 0; + count -= 2; + buf += 2; + } else { + if (count < 3) { + bt_dev_err(data->hdev, "short block header"); + kfree_skb(data->reassembly); + data->reassembly = NULL; + break; + } + + len = (buf[2] == 0) ? 256 : buf[2]; + count -= 3; + buf += 3; + } + + if (count < len) { + bt_dev_err(data->hdev, "block extends over URB buffer ranges"); + kfree_skb(data->reassembly); + data->reassembly = NULL; + break; + } + + if ((hdr & 0xe1) == 0xc1 && + bfusb_recv_block(data, hdr, buf, len) < 0) + data->hdev->stat.err_rx++; + + count -= len; + buf += len; + } + + skb_unlink(skb, &data->pending_q); + kfree_skb(skb); + + bfusb_rx_submit(data, urb); + + read_unlock(&data->lock); + + return; + +resubmit: + urb->dev = data->udev; + + err = usb_submit_urb(urb, GFP_ATOMIC); + if (err) { + bt_dev_err(data->hdev, "bulk resubmit failed urb %p err %d", + urb, err); + } + +unlock: + read_unlock(&data->lock); +} + +static int bfusb_open(struct hci_dev *hdev) +{ + struct bfusb_data *data = hci_get_drvdata(hdev); + unsigned long flags; + int i, err; + + BT_DBG("hdev %p bfusb %p", hdev, data); + + write_lock_irqsave(&data->lock, flags); + + err = bfusb_rx_submit(data, NULL); + if (!err) { + for (i = 1; i < BFUSB_MAX_BULK_RX; i++) + bfusb_rx_submit(data, NULL); + } + + write_unlock_irqrestore(&data->lock, flags); + + return err; +} + +static int bfusb_flush(struct hci_dev *hdev) +{ + struct bfusb_data *data = hci_get_drvdata(hdev); + + BT_DBG("hdev %p bfusb %p", hdev, data); + + skb_queue_purge(&data->transmit_q); + + return 0; +} + +static int bfusb_close(struct hci_dev *hdev) +{ + struct bfusb_data *data = hci_get_drvdata(hdev); + unsigned long flags; + + BT_DBG("hdev %p bfusb %p", hdev, data); + + write_lock_irqsave(&data->lock, flags); + write_unlock_irqrestore(&data->lock, flags); + + bfusb_unlink_urbs(data); + bfusb_flush(hdev); + + return 0; +} + +static int bfusb_send_frame(struct hci_dev *hdev, struct sk_buff *skb) +{ + struct bfusb_data *data = hci_get_drvdata(hdev); + struct sk_buff *nskb; + unsigned char buf[3]; + int sent = 0, size, count; + + BT_DBG("hdev %p skb %p type %d len %d", hdev, skb, + hci_skb_pkt_type(skb), skb->len); + + switch (hci_skb_pkt_type(skb)) { + case HCI_COMMAND_PKT: + hdev->stat.cmd_tx++; + break; + case HCI_ACLDATA_PKT: + hdev->stat.acl_tx++; + break; + case HCI_SCODATA_PKT: + hdev->stat.sco_tx++; + break; + } + + /* Prepend skb with frame type */ + memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1); + + count = skb->len; + + /* Max HCI frame size seems to be 1511 + 1 */ + nskb = bt_skb_alloc(count + 32, GFP_KERNEL); + if (!nskb) { + bt_dev_err(hdev, "Can't allocate memory for new packet"); + return -ENOMEM; + } + + nskb->dev = (void *) data; + + while (count) { + size = min_t(uint, count, BFUSB_MAX_BLOCK_SIZE); + + buf[0] = 0xc1 | ((sent == 0) ? 0x04 : 0) | ((count == size) ? 0x08 : 0); + buf[1] = 0x00; + buf[2] = (size == BFUSB_MAX_BLOCK_SIZE) ? 0 : size; + + skb_put_data(nskb, buf, 3); + skb_copy_from_linear_data_offset(skb, sent, skb_put(nskb, size), size); + + sent += size; + count -= size; + } + + /* Don't send frame with multiple size of bulk max packet */ + if ((nskb->len % data->bulk_pkt_size) == 0) { + buf[0] = 0xdd; + buf[1] = 0x00; + skb_put_data(nskb, buf, 2); + } + + read_lock(&data->lock); + + skb_queue_tail(&data->transmit_q, nskb); + bfusb_tx_wakeup(data); + + read_unlock(&data->lock); + + kfree_skb(skb); + + return 0; +} + +static int bfusb_load_firmware(struct bfusb_data *data, + const unsigned char *firmware, int count) +{ + unsigned char *buf; + int err, pipe, len, size, sent = 0; + + BT_DBG("bfusb %p udev %p", data, data->udev); + + BT_INFO("BlueFRITZ! USB loading firmware"); + + buf = kmalloc(BFUSB_MAX_BLOCK_SIZE + 3, GFP_KERNEL); + if (!buf) { + BT_ERR("Can't allocate memory chunk for firmware"); + return -ENOMEM; + } + + pipe = usb_sndctrlpipe(data->udev, 0); + + if (usb_control_msg(data->udev, pipe, USB_REQ_SET_CONFIGURATION, + 0, 1, 0, NULL, 0, USB_CTRL_SET_TIMEOUT) < 0) { + BT_ERR("Can't change to loading configuration"); + kfree(buf); + return -EBUSY; + } + + data->udev->toggle[0] = data->udev->toggle[1] = 0; + + pipe = usb_sndbulkpipe(data->udev, data->bulk_out_ep); + + while (count) { + size = min_t(uint, count, BFUSB_MAX_BLOCK_SIZE + 3); + + memcpy(buf, firmware + sent, size); + + err = usb_bulk_msg(data->udev, pipe, buf, size, + &len, BFUSB_BLOCK_TIMEOUT); + + if (err || (len != size)) { + BT_ERR("Error in firmware loading"); + goto error; + } + + sent += size; + count -= size; + } + + err = usb_bulk_msg(data->udev, pipe, NULL, 0, + &len, BFUSB_BLOCK_TIMEOUT); + if (err < 0) { + BT_ERR("Error in null packet request"); + goto error; + } + + pipe = usb_sndctrlpipe(data->udev, 0); + + err = usb_control_msg(data->udev, pipe, USB_REQ_SET_CONFIGURATION, + 0, 2, 0, NULL, 0, USB_CTRL_SET_TIMEOUT); + if (err < 0) { + BT_ERR("Can't change to running configuration"); + goto error; + } + + data->udev->toggle[0] = data->udev->toggle[1] = 0; + + BT_INFO("BlueFRITZ! USB device ready"); + + kfree(buf); + return 0; + +error: + kfree(buf); + + pipe = usb_sndctrlpipe(data->udev, 0); + + usb_control_msg(data->udev, pipe, USB_REQ_SET_CONFIGURATION, + 0, 0, 0, NULL, 0, USB_CTRL_SET_TIMEOUT); + + return err; +} + +static int bfusb_probe(struct usb_interface *intf, const struct usb_device_id *id) +{ + const struct firmware *firmware; + struct usb_device *udev = interface_to_usbdev(intf); + struct usb_host_endpoint *bulk_out_ep; + struct usb_host_endpoint *bulk_in_ep; + struct hci_dev *hdev; + struct bfusb_data *data; + + BT_DBG("intf %p id %p", intf, id); + + /* Check number of endpoints */ + if (intf->cur_altsetting->desc.bNumEndpoints < 2) + return -EIO; + + bulk_out_ep = &intf->cur_altsetting->endpoint[0]; + bulk_in_ep = &intf->cur_altsetting->endpoint[1]; + + if (!bulk_out_ep || !bulk_in_ep) { + BT_ERR("Bulk endpoints not found"); + goto done; + } + + /* Initialize control structure and load firmware */ + data = devm_kzalloc(&intf->dev, sizeof(struct bfusb_data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->udev = udev; + data->bulk_in_ep = bulk_in_ep->desc.bEndpointAddress; + data->bulk_out_ep = bulk_out_ep->desc.bEndpointAddress; + data->bulk_pkt_size = le16_to_cpu(bulk_out_ep->desc.wMaxPacketSize); + + if (!data->bulk_pkt_size) + goto done; + + rwlock_init(&data->lock); + + data->reassembly = NULL; + + skb_queue_head_init(&data->transmit_q); + skb_queue_head_init(&data->pending_q); + skb_queue_head_init(&data->completed_q); + + if (request_firmware(&firmware, "bfubase.frm", &udev->dev) < 0) { + BT_ERR("Firmware request failed"); + goto done; + } + + BT_DBG("firmware data %p size %zu", firmware->data, firmware->size); + + if (bfusb_load_firmware(data, firmware->data, firmware->size) < 0) { + BT_ERR("Firmware loading failed"); + goto release; + } + + release_firmware(firmware); + + /* Initialize and register HCI device */ + hdev = hci_alloc_dev(); + if (!hdev) { + BT_ERR("Can't allocate HCI device"); + goto done; + } + + data->hdev = hdev; + + hdev->bus = HCI_USB; + hci_set_drvdata(hdev, data); + SET_HCIDEV_DEV(hdev, &intf->dev); + + hdev->open = bfusb_open; + hdev->close = bfusb_close; + hdev->flush = bfusb_flush; + hdev->send = bfusb_send_frame; + + hci_set_quirk(hdev, HCI_QUIRK_BROKEN_LOCAL_COMMANDS); + + if (hci_register_dev(hdev) < 0) { + BT_ERR("Can't register HCI device"); + hci_free_dev(hdev); + goto done; + } + + usb_set_intfdata(intf, data); + + return 0; + +release: + release_firmware(firmware); + +done: + return -EIO; +} + +static void bfusb_disconnect(struct usb_interface *intf) +{ + struct bfusb_data *data = usb_get_intfdata(intf); + struct hci_dev *hdev = data->hdev; + + BT_DBG("intf %p", intf); + + if (!hdev) + return; + + usb_set_intfdata(intf, NULL); + + bfusb_close(hdev); + + hci_unregister_dev(hdev); + hci_free_dev(hdev); +} + +static struct usb_driver bfusb_driver = { + .name = "bfusb", + .probe = bfusb_probe, + .disconnect = bfusb_disconnect, + .id_table = bfusb_table, + .disable_hub_initiated_lpm = 1, +}; + +module_usb_driver(bfusb_driver); + +MODULE_AUTHOR("Marcel Holtmann "); +MODULE_DESCRIPTION("BlueFRITZ! USB driver ver " VERSION); +MODULE_VERSION(VERSION); +MODULE_LICENSE("GPL"); +MODULE_FIRMWARE("bfubase.frm"); -- cgit v1.3.1