x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

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) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

1 files changed, 443 insertions, 0 deletions

diff --git a/drivers/input/tablet/hanwang.c b/drivers/input/tablet/hanwang.c
new file mode 100644
index 000000000..fd5a7e761
--- /dev/null
+++ b/drivers/input/tablet/hanwang.c
@@ -0,0 +1,443 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  USB Hanwang tablet support
+ *
+ *  Copyright (c) 2010 Xing Wei <weixing@hanwang.com.cn>
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/usb/input.h>
+
+MODULE_AUTHOR("Xing Wei <weixing@hanwang.com.cn>");
+MODULE_DESCRIPTION("USB Hanwang tablet driver");
+MODULE_LICENSE("GPL");
+
+#define USB_VENDOR_ID_HANWANG		0x0b57
+#define HANWANG_TABLET_INT_CLASS	0x0003
+#define HANWANG_TABLET_INT_SUB_CLASS	0x0001
+#define HANWANG_TABLET_INT_PROTOCOL	0x0002
+
+#define ART_MASTER_PKGLEN_MAX	10
+
+/* device IDs */
+#define STYLUS_DEVICE_ID	0x02
+#define TOUCH_DEVICE_ID		0x03
+#define CURSOR_DEVICE_ID	0x06
+#define ERASER_DEVICE_ID	0x0A
+#define PAD_DEVICE_ID		0x0F
+
+/* match vendor and interface info  */
+#define HANWANG_TABLET_DEVICE(vend, cl, sc, pr) \
+	.match_flags = USB_DEVICE_ID_MATCH_VENDOR \
+		| USB_DEVICE_ID_MATCH_INT_INFO, \
+	.idVendor = (vend), \
+	.bInterfaceClass = (cl), \
+	.bInterfaceSubClass = (sc), \
+	.bInterfaceProtocol = (pr)
+
+enum hanwang_tablet_type {
+	HANWANG_ART_MASTER_III,
+	HANWANG_ART_MASTER_HD,
+	HANWANG_ART_MASTER_II,
+};
+
+struct hanwang {
+	unsigned char *data;
+	dma_addr_t data_dma;
+	struct input_dev *dev;
+	struct usb_device *usbdev;
+	struct urb *irq;
+	const struct hanwang_features *features;
+	unsigned int current_tool;
+	unsigned int current_id;
+	char name[64];
+	char phys[32];
+};
+
+struct hanwang_features {
+	unsigned short pid;
+	char *name;
+	enum hanwang_tablet_type type;
+	int pkg_len;
+	int max_x;
+	int max_y;
+	int max_tilt_x;
+	int max_tilt_y;
+	int max_pressure;
+};
+
+static const struct hanwang_features features_array[] = {
+	{ 0x8528, "Hanwang Art Master III 0906", HANWANG_ART_MASTER_III,
+	  ART_MASTER_PKGLEN_MAX, 0x5757, 0x3692, 0x3f, 0x7f, 2048 },
+	{ 0x8529, "Hanwang Art Master III 0604", HANWANG_ART_MASTER_III,
+	  ART_MASTER_PKGLEN_MAX, 0x3d84, 0x2672, 0x3f, 0x7f, 2048 },
+	{ 0x852a, "Hanwang Art Master III 1308", HANWANG_ART_MASTER_III,
+	  ART_MASTER_PKGLEN_MAX, 0x7f00, 0x4f60, 0x3f, 0x7f, 2048 },
+	{ 0x8401, "Hanwang Art Master HD 5012", HANWANG_ART_MASTER_HD,
+	  ART_MASTER_PKGLEN_MAX, 0x678e, 0x4150, 0x3f, 0x7f, 1024 },
+	{ 0x8503, "Hanwang Art Master II", HANWANG_ART_MASTER_II,
+	  ART_MASTER_PKGLEN_MAX, 0x27de, 0x1cfe, 0x3f, 0x7f, 1024 },
+};
+
+static const int hw_eventtypes[] = {
+	EV_KEY, EV_ABS, EV_MSC,
+};
+
+static const int hw_absevents[] = {
+	ABS_X, ABS_Y, ABS_TILT_X, ABS_TILT_Y, ABS_WHEEL,
+	ABS_RX, ABS_RY, ABS_PRESSURE, ABS_MISC,
+};
+
+static const int hw_btnevents[] = {
+	BTN_STYLUS, BTN_STYLUS2, BTN_TOOL_PEN, BTN_TOOL_RUBBER,
+	BTN_TOOL_MOUSE, BTN_TOOL_FINGER,
+	BTN_0, BTN_1, BTN_2, BTN_3, BTN_4, BTN_5, BTN_6, BTN_7, BTN_8,
+};
+
+static const int hw_mscevents[] = {
+	MSC_SERIAL,
+};
+
+static void hanwang_parse_packet(struct hanwang *hanwang)
+{
+	unsigned char *data = hanwang->data;
+	struct input_dev *input_dev = hanwang->dev;
+	struct usb_device *dev = hanwang->usbdev;
+	enum hanwang_tablet_type type = hanwang->features->type;
+	int i;
+	u16 p;
+
+	if (type == HANWANG_ART_MASTER_II) {
+		hanwang->current_tool = BTN_TOOL_PEN;
+		hanwang->current_id = STYLUS_DEVICE_ID;
+	}
+
+	switch (data[0]) {
+	case 0x02:	/* data packet */
+		switch (data[1]) {
+		case 0x80:	/* tool prox out */
+			if (type != HANWANG_ART_MASTER_II) {
+				hanwang->current_id = 0;
+				input_report_key(input_dev,
+						 hanwang->current_tool, 0);
+			}
+			break;
+
+		case 0x00:	/* artmaster ii pen leave */
+			if (type == HANWANG_ART_MASTER_II) {
+				hanwang->current_id = 0;
+				input_report_key(input_dev,
+						 hanwang->current_tool, 0);
+			}
+			break;
+
+		case 0xc2:	/* first time tool prox in */
+			switch (data[3] & 0xf0) {
+			case 0x20:	/* art_master III */
+			case 0x30:	/* art_master_HD */
+				hanwang->current_id = STYLUS_DEVICE_ID;
+				hanwang->current_tool = BTN_TOOL_PEN;
+				input_report_key(input_dev, BTN_TOOL_PEN, 1);
+				break;
+			case 0xa0:	/* art_master III */
+			case 0xb0:	/* art_master_HD */
+				hanwang->current_id = ERASER_DEVICE_ID;
+				hanwang->current_tool = BTN_TOOL_RUBBER;
+				input_report_key(input_dev, BTN_TOOL_RUBBER, 1);
+				break;
+			default:
+				hanwang->current_id = 0;
+				dev_dbg(&dev->dev,
+					"unknown tablet tool %02x\n", data[0]);
+				break;
+			}
+			break;
+
+		default:	/* tool data packet */
+			switch (type) {
+			case HANWANG_ART_MASTER_III:
+				p = (data[6] << 3) |
+				    ((data[7] & 0xc0) >> 5) |
+				    (data[1] & 0x01);
+				break;
+
+			case HANWANG_ART_MASTER_HD:
+			case HANWANG_ART_MASTER_II:
+				p = (data[7] >> 6) | (data[6] << 2);
+				break;
+
+			default:
+				p = 0;
+				break;
+			}
+
+			input_report_abs(input_dev, ABS_X,
+					 be16_to_cpup((__be16 *)&data[2]));
+			input_report_abs(input_dev, ABS_Y,
+					 be16_to_cpup((__be16 *)&data[4]));
+			input_report_abs(input_dev, ABS_PRESSURE, p);
+			input_report_abs(input_dev, ABS_TILT_X, data[7] & 0x3f);
+			input_report_abs(input_dev, ABS_TILT_Y, data[8] & 0x7f);
+			input_report_key(input_dev, BTN_STYLUS, data[1] & 0x02);
+
+			if (type != HANWANG_ART_MASTER_II)
+				input_report_key(input_dev, BTN_STYLUS2,
+						 data[1] & 0x04);
+			else
+				input_report_key(input_dev, BTN_TOOL_PEN, 1);
+
+			break;
+		}
+
+		input_report_abs(input_dev, ABS_MISC, hanwang->current_id);
+		input_event(input_dev, EV_MSC, MSC_SERIAL,
+				hanwang->features->pid);
+		break;
+
+	case 0x0c:
+		/* roll wheel */
+		hanwang->current_id = PAD_DEVICE_ID;
+
+		switch (type) {
+		case HANWANG_ART_MASTER_III:
+			input_report_key(input_dev, BTN_TOOL_FINGER,
+					 data[1] || data[2] || data[3]);
+			input_report_abs(input_dev, ABS_WHEEL, data[1]);
+			input_report_key(input_dev, BTN_0, data[2]);
+			for (i = 0; i < 8; i++)
+				input_report_key(input_dev,
+					 BTN_1 + i, data[3] & (1 << i));
+			break;
+
+		case HANWANG_ART_MASTER_HD:
+			input_report_key(input_dev, BTN_TOOL_FINGER, data[1] ||
+					data[2] || data[3] || data[4] ||
+					data[5] || data[6]);
+			input_report_abs(input_dev, ABS_RX,
+					((data[1] & 0x1f) << 8) | data[2]);
+			input_report_abs(input_dev, ABS_RY,
+					((data[3] & 0x1f) << 8) | data[4]);
+			input_report_key(input_dev, BTN_0, data[5] & 0x01);
+			for (i = 0; i < 4; i++) {
+				input_report_key(input_dev,
+					 BTN_1 + i, data[5] & (1 << i));
+				input_report_key(input_dev,
+					 BTN_5 + i, data[6] & (1 << i));
+			}
+			break;
+
+		case HANWANG_ART_MASTER_II:
+			dev_dbg(&dev->dev, "error packet  %02x\n", data[0]);
+			return;
+		}
+
+		input_report_abs(input_dev, ABS_MISC, hanwang->current_id);
+		input_event(input_dev, EV_MSC, MSC_SERIAL, 0xffffffff);
+		break;
+
+	default:
+		dev_dbg(&dev->dev, "error packet  %02x\n", data[0]);
+		break;
+	}
+
+	input_sync(input_dev);
+}
+
+static void hanwang_irq(struct urb *urb)
+{
+	struct hanwang *hanwang = urb->context;
+	struct usb_device *dev = hanwang->usbdev;
+	int retval;
+
+	switch (urb->status) {
+	case 0:
+		/* success */;
+		hanwang_parse_packet(hanwang);
+		break;
+	case -ECONNRESET:
+	case -ENOENT:
+	case -ESHUTDOWN:
+		/* this urb is terminated, clean up */
+		dev_err(&dev->dev, "%s - urb shutting down with status: %d",
+			__func__, urb->status);
+		return;
+	default:
+		dev_err(&dev->dev, "%s - nonzero urb status received: %d",
+			__func__, urb->status);
+		break;
+	}
+
+	retval = usb_submit_urb(urb, GFP_ATOMIC);
+	if (retval)
+		dev_err(&dev->dev, "%s - usb_submit_urb failed with result %d",
+			__func__, retval);
+}
+
+static int hanwang_open(struct input_dev *dev)
+{
+	struct hanwang *hanwang = input_get_drvdata(dev);
+
+	hanwang->irq->dev = hanwang->usbdev;
+	if (usb_submit_urb(hanwang->irq, GFP_KERNEL))
+		return -EIO;
+
+	return 0;
+}
+
+static void hanwang_close(struct input_dev *dev)
+{
+	struct hanwang *hanwang = input_get_drvdata(dev);
+
+	usb_kill_urb(hanwang->irq);
+}
+
+static bool get_features(struct usb_device *dev, struct hanwang *hanwang)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(features_array); i++) {
+		if (le16_to_cpu(dev->descriptor.idProduct) ==
+				features_array[i].pid) {
+			hanwang->features = &features_array[i];
+			return true;
+		}
+	}
+
+	return false;
+}
+
+
+static int hanwang_probe(struct usb_interface *intf, const struct usb_device_id *id)
+{
+	struct usb_device *dev = interface_to_usbdev(intf);
+	struct usb_endpoint_descriptor *endpoint;
+	struct hanwang *hanwang;
+	struct input_dev *input_dev;
+	int error;
+	int i;
+
+	if (intf->cur_altsetting->desc.bNumEndpoints < 1)
+		return -ENODEV;
+
+	hanwang = kzalloc_obj(*hanwang);
+	input_dev = input_allocate_device();
+	if (!hanwang || !input_dev) {
+		error = -ENOMEM;
+		goto fail1;
+	}
+
+	if (!get_features(dev, hanwang)) {
+		error = -ENXIO;
+		goto fail1;
+	}
+
+	hanwang->data = usb_alloc_coherent(dev, hanwang->features->pkg_len,
+					GFP_KERNEL, &hanwang->data_dma);
+	if (!hanwang->data) {
+		error = -ENOMEM;
+		goto fail1;
+	}
+
+	hanwang->irq = usb_alloc_urb(0, GFP_KERNEL);
+	if (!hanwang->irq) {
+		error = -ENOMEM;
+		goto fail2;
+	}
+
+	hanwang->usbdev = dev;
+	hanwang->dev = input_dev;
+
+	usb_make_path(dev, hanwang->phys, sizeof(hanwang->phys));
+	strlcat(hanwang->phys, "/input0", sizeof(hanwang->phys));
+
+	strscpy(hanwang->name, hanwang->features->name, sizeof(hanwang->name));
+	input_dev->name = hanwang->name;
+	input_dev->phys = hanwang->phys;
+	usb_to_input_id(dev, &input_dev->id);
+	input_dev->dev.parent = &intf->dev;
+
+	input_set_drvdata(input_dev, hanwang);
+
+	input_dev->open = hanwang_open;
+	input_dev->close = hanwang_close;
+
+	for (i = 0; i < ARRAY_SIZE(hw_eventtypes); ++i)
+		__set_bit(hw_eventtypes[i], input_dev->evbit);
+
+	for (i = 0; i < ARRAY_SIZE(hw_absevents); ++i)
+		__set_bit(hw_absevents[i], input_dev->absbit);
+
+	for (i = 0; i < ARRAY_SIZE(hw_btnevents); ++i)
+		__set_bit(hw_btnevents[i], input_dev->keybit);
+
+	for (i = 0; i < ARRAY_SIZE(hw_mscevents); ++i)
+		__set_bit(hw_mscevents[i], input_dev->mscbit);
+
+	input_set_abs_params(input_dev, ABS_X,
+			     0, hanwang->features->max_x, 4, 0);
+	input_set_abs_params(input_dev, ABS_Y,
+			     0, hanwang->features->max_y, 4, 0);
+	input_set_abs_params(input_dev, ABS_TILT_X,
+			     0, hanwang->features->max_tilt_x, 0, 0);
+	input_set_abs_params(input_dev, ABS_TILT_Y,
+			     0, hanwang->features->max_tilt_y, 0, 0);
+	input_set_abs_params(input_dev, ABS_PRESSURE,
+			     0, hanwang->features->max_pressure, 0, 0);
+
+	endpoint = &intf->cur_altsetting->endpoint[0].desc;
+	usb_fill_int_urb(hanwang->irq, dev,
+			usb_rcvintpipe(dev, endpoint->bEndpointAddress),
+			hanwang->data, hanwang->features->pkg_len,
+			hanwang_irq, hanwang, endpoint->bInterval);
+	hanwang->irq->transfer_dma = hanwang->data_dma;
+	hanwang->irq->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+
+	error = input_register_device(hanwang->dev);
+	if (error)
+		goto fail3;
+
+	usb_set_intfdata(intf, hanwang);
+
+	return 0;
+
+ fail3:	usb_free_urb(hanwang->irq);
+ fail2:	usb_free_coherent(dev, hanwang->features->pkg_len,
+			hanwang->data, hanwang->data_dma);
+ fail1:	input_free_device(input_dev);
+	kfree(hanwang);
+	return error;
+
+}
+
+static void hanwang_disconnect(struct usb_interface *intf)
+{
+	struct hanwang *hanwang = usb_get_intfdata(intf);
+
+	input_unregister_device(hanwang->dev);
+	usb_free_urb(hanwang->irq);
+	usb_free_coherent(interface_to_usbdev(intf),
+			hanwang->features->pkg_len, hanwang->data,
+			hanwang->data_dma);
+	kfree(hanwang);
+	usb_set_intfdata(intf, NULL);
+}
+
+static const struct usb_device_id hanwang_ids[] = {
+	{ HANWANG_TABLET_DEVICE(USB_VENDOR_ID_HANWANG, HANWANG_TABLET_INT_CLASS,
+		HANWANG_TABLET_INT_SUB_CLASS, HANWANG_TABLET_INT_PROTOCOL) },
+	{}
+};
+
+MODULE_DEVICE_TABLE(usb, hanwang_ids);
+
+static struct usb_driver hanwang_driver = {
+	.name		= "hanwang",
+	.probe		= hanwang_probe,
+	.disconnect	= hanwang_disconnect,
+	.id_table	= hanwang_ids,
+};
+
+module_usb_driver(hanwang_driver);