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, 548 insertions, 0 deletions

diff --git a/drivers/input/joystick/adi.c b/drivers/input/joystick/adi.c
new file mode 100644
index 000000000..e07b71978
--- /dev/null
+++ b/drivers/input/joystick/adi.c
@@ -0,0 +1,548 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Copyright (c) 1998-2005 Vojtech Pavlik
+ */
+
+/*
+ * Logitech ADI joystick family driver for Linux
+ */
+
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/input.h>
+#include <linux/gameport.h>
+#include <linux/jiffies.h>
+
+#define DRIVER_DESC	"Logitech ADI joystick family driver"
+
+MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_LICENSE("GPL");
+
+/*
+ * Times, array sizes, flags, ids.
+ */
+
+#define ADI_MAX_START		200	/* Trigger to packet timeout [200us] */
+#define ADI_MAX_STROBE		40	/* Single bit timeout [40us] */
+#define ADI_INIT_DELAY		10	/* Delay after init packet [10ms] */
+#define ADI_DATA_DELAY		4	/* Delay after data packet [4ms] */
+
+#define ADI_MAX_LENGTH		256
+#define ADI_MIN_LENGTH		8
+#define ADI_MIN_LEN_LENGTH	10
+#define ADI_MIN_ID_LENGTH	66
+#define ADI_MAX_NAME_LENGTH	64
+#define ADI_MAX_CNAME_LENGTH	16
+#define ADI_MAX_PHYS_LENGTH	64
+
+#define ADI_FLAG_HAT		0x04
+#define ADI_FLAG_10BIT		0x08
+
+#define ADI_ID_TPD		0x01
+#define ADI_ID_WGP		0x06
+#define ADI_ID_WGPE		0x08
+#define ADI_ID_MAX		0x0a
+
+/*
+ * Names, buttons, axes ...
+ */
+
+static char *adi_names[] = {	"WingMan Extreme Digital", "ThunderPad Digital", "SideCar", "CyberMan 2",
+				"WingMan Interceptor", "WingMan Formula", "WingMan GamePad",
+				"WingMan Extreme Digital 3D", "WingMan GamePad Extreme",
+				"WingMan GamePad USB", "Unknown Device %#x" };
+
+static char adi_wmgpe_abs[] =	{ ABS_X, ABS_Y, ABS_HAT0X, ABS_HAT0Y };
+static char adi_wmi_abs[] =	{ ABS_X, ABS_Y, ABS_THROTTLE, ABS_HAT0X, ABS_HAT0Y, ABS_HAT1X, ABS_HAT1Y, ABS_HAT2X, ABS_HAT2Y };
+static char adi_wmed3d_abs[] =	{ ABS_X, ABS_Y, ABS_THROTTLE, ABS_RZ, ABS_HAT0X, ABS_HAT0Y };
+static char adi_cm2_abs[] =	{ ABS_X, ABS_Y, ABS_Z, ABS_RX, ABS_RY, ABS_RZ };
+static char adi_wmf_abs[] =	{ ABS_WHEEL, ABS_GAS, ABS_BRAKE, ABS_HAT0X, ABS_HAT0Y, ABS_HAT1X, ABS_HAT1Y, ABS_HAT2X, ABS_HAT2Y };
+
+static short adi_wmgpe_key[] =	{ BTN_A, BTN_B, BTN_C, BTN_X, BTN_Y, BTN_Z,  BTN_TL, BTN_TR, BTN_START, BTN_MODE, BTN_SELECT };
+static short adi_wmi_key[] =	{ BTN_TRIGGER,  BTN_TOP, BTN_THUMB, BTN_TOP2, BTN_BASE, BTN_BASE2, BTN_BASE3, BTN_BASE4, BTN_EXTRA };
+static short adi_wmed3d_key[] =	{ BTN_TRIGGER, BTN_THUMB, BTN_THUMB2, BTN_TOP, BTN_TOP2, BTN_BASE, BTN_BASE2 };
+static short adi_cm2_key[] =	{ BTN_1, BTN_2, BTN_3, BTN_4, BTN_5, BTN_6, BTN_7, BTN_8 };
+
+static char* adi_abs[] = { adi_wmi_abs, adi_wmgpe_abs, adi_wmf_abs, adi_cm2_abs, adi_wmi_abs, adi_wmf_abs,
+			   adi_wmgpe_abs, adi_wmed3d_abs, adi_wmgpe_abs, adi_wmgpe_abs, adi_wmi_abs };
+
+static short* adi_key[] = { adi_wmi_key, adi_wmgpe_key, adi_cm2_key, adi_cm2_key, adi_wmi_key, adi_cm2_key,
+			    adi_wmgpe_key, adi_wmed3d_key, adi_wmgpe_key, adi_wmgpe_key, adi_wmi_key };
+
+/*
+ * Hat to axis conversion arrays.
+ */
+
+static struct {
+	int x;
+	int y;
+} adi_hat_to_axis[] = {{ 0, 0}, { 0,-1}, { 1,-1}, { 1, 0}, { 1, 1}, { 0, 1}, {-1, 1}, {-1, 0}, {-1,-1}};
+
+/*
+ * Per-port information.
+ */
+
+struct adi {
+	struct input_dev *dev;
+	int length;
+	int ret;
+	int idx;
+	unsigned char id;
+	char buttons;
+	char axes10;
+	char axes8;
+	signed char pad;
+	char hats;
+	char *abs;
+	short *key;
+	char name[ADI_MAX_NAME_LENGTH];
+	char cname[ADI_MAX_CNAME_LENGTH];
+	char phys[ADI_MAX_PHYS_LENGTH];
+	unsigned char data[ADI_MAX_LENGTH];
+};
+
+struct adi_port {
+	struct gameport *gameport;
+	struct adi adi[2];
+	int bad;
+	int reads;
+};
+
+/*
+ * adi_read_packet() reads a Logitech ADI packet.
+ */
+
+static void adi_read_packet(struct adi_port *port)
+{
+	struct adi *adi = port->adi;
+	struct gameport *gameport = port->gameport;
+	unsigned char u, v, w, x;
+	int t[2], s[2], i;
+	unsigned long flags;
+
+	for (i = 0; i < 2; i++) {
+		adi[i].ret = -1;
+		t[i] = gameport_time(gameport, ADI_MAX_START);
+		s[i] = 0;
+	}
+
+	local_irq_save(flags);
+
+	gameport_trigger(gameport);
+	v = gameport_read(gameport);
+
+	do {
+		u = v;
+		w = u ^ (v = x = gameport_read(gameport));
+		for (i = 0; i < 2; i++, w >>= 2, x >>= 2) {
+			t[i]--;
+			if ((w & 0x30) && s[i]) {
+				if ((w & 0x30) < 0x30 && adi[i].ret < ADI_MAX_LENGTH && t[i] > 0) {
+					adi[i].data[++adi[i].ret] = w;
+					t[i] = gameport_time(gameport, ADI_MAX_STROBE);
+				} else t[i] = 0;
+			} else if (!(x & 0x30)) s[i] = 1;
+		}
+	} while (t[0] > 0 || t[1] > 0);
+
+	local_irq_restore(flags);
+
+	return;
+}
+
+/*
+ * adi_move_bits() detects a possible 2-stream mode, and moves
+ * the bits accordingly.
+ */
+
+static void adi_move_bits(struct adi_port *port, int length)
+{
+	int i;
+	struct adi *adi = port->adi;
+
+	adi[0].idx = adi[1].idx = 0;
+
+	if (adi[0].ret <= 0 || adi[1].ret <= 0) return;
+	if (adi[0].data[0] & 0x20 || ~adi[1].data[0] & 0x20) return;
+
+	for (i = 1; i <= adi[1].ret; i++)
+		adi[0].data[((length - 1) >> 1) + i + 1] = adi[1].data[i];
+
+	adi[0].ret += adi[1].ret;
+	adi[1].ret = -1;
+}
+
+/*
+ * adi_get_bits() gathers bits from the data packet.
+ */
+
+static inline int adi_get_bits(struct adi *adi, int count)
+{
+	int bits = 0;
+	int i;
+	if ((adi->idx += count) > adi->ret) return 0;
+	for (i = 0; i < count; i++)
+		bits |= ((adi->data[adi->idx - i] >> 5) & 1) << i;
+	return bits;
+}
+
+/*
+ * adi_decode() decodes Logitech joystick data into input events.
+ */
+
+static int adi_decode(struct adi *adi)
+{
+	struct input_dev *dev = adi->dev;
+	char *abs = adi->abs;
+	short *key = adi->key;
+	int i, t;
+
+	if (adi->ret < adi->length || adi->id != (adi_get_bits(adi, 4) | (adi_get_bits(adi, 4) << 4)))
+		return -1;
+
+	for (i = 0; i < adi->axes10; i++)
+		input_report_abs(dev, *abs++, adi_get_bits(adi, 10));
+
+	for (i = 0; i < adi->axes8; i++)
+		input_report_abs(dev, *abs++, adi_get_bits(adi, 8));
+
+	for (i = 0; i < adi->buttons && i < 63; i++) {
+		if (i == adi->pad) {
+			t = adi_get_bits(adi, 4);
+			input_report_abs(dev, *abs++, ((t >> 2) & 1) - ( t       & 1));
+			input_report_abs(dev, *abs++, ((t >> 1) & 1) - ((t >> 3) & 1));
+		}
+		input_report_key(dev, *key++, adi_get_bits(adi, 1));
+	}
+
+	for (i = 0; i < adi->hats; i++) {
+		if ((t = adi_get_bits(adi, 4)) > 8) t = 0;
+		input_report_abs(dev, *abs++, adi_hat_to_axis[t].x);
+		input_report_abs(dev, *abs++, adi_hat_to_axis[t].y);
+	}
+
+	for (i = 63; i < adi->buttons; i++)
+		input_report_key(dev, *key++, adi_get_bits(adi, 1));
+
+	input_sync(dev);
+
+	return 0;
+}
+
+/*
+ * adi_read() reads the data packet and decodes it.
+ */
+
+static int adi_read(struct adi_port *port)
+{
+	int i;
+	int result = 0;
+
+	adi_read_packet(port);
+	adi_move_bits(port, port->adi[0].length);
+
+	for (i = 0; i < 2; i++)
+		if (port->adi[i].length)
+			 result |= adi_decode(port->adi + i);
+
+	return result;
+}
+
+/*
+ * adi_poll() repeatedly polls the Logitech joysticks.
+ */
+
+static void adi_poll(struct gameport *gameport)
+{
+	struct adi_port *port = gameport_get_drvdata(gameport);
+
+	port->bad -= adi_read(port);
+	port->reads++;
+}
+
+/*
+ * adi_open() is a callback from the input open routine.
+ */
+
+static int adi_open(struct input_dev *dev)
+{
+	struct adi_port *port = input_get_drvdata(dev);
+
+	gameport_start_polling(port->gameport);
+	return 0;
+}
+
+/*
+ * adi_close() is a callback from the input close routine.
+ */
+
+static void adi_close(struct input_dev *dev)
+{
+	struct adi_port *port = input_get_drvdata(dev);
+
+	gameport_stop_polling(port->gameport);
+}
+
+/*
+ * adi_init_digital() sends a trigger & delay sequence
+ * to reset and initialize a Logitech joystick into digital mode.
+ */
+
+static void adi_init_digital(struct gameport *gameport)
+{
+	static const int seq[] = { 4, -2, -3, 10, -6, -11, -7, -9, 11, 0 };
+	int i;
+
+	for (i = 0; seq[i]; i++) {
+		gameport_trigger(gameport);
+		if (seq[i] > 0)
+			msleep(seq[i]);
+		if (seq[i] < 0) {
+			mdelay(-seq[i]);
+			udelay(-seq[i]*14);	/* It looks like mdelay() is off by approx 1.4% */
+		}
+	}
+}
+
+static void adi_id_decode(struct adi *adi, struct adi_port *port)
+{
+	int i, t;
+
+	if (adi->ret < ADI_MIN_ID_LENGTH) /* Minimum ID packet length */
+		return;
+
+	if (adi->ret < (t = adi_get_bits(adi, 10))) {
+		printk(KERN_WARNING "adi: Short ID packet: reported: %d != read: %d\n", t, adi->ret);
+		return;
+	}
+
+	adi->id = adi_get_bits(adi, 4) | (adi_get_bits(adi, 4) << 4);
+
+	if ((t = adi_get_bits(adi, 4)) & ADI_FLAG_HAT) adi->hats++;
+
+	adi->length = adi_get_bits(adi, 10);
+
+	if (adi->length >= ADI_MAX_LENGTH || adi->length < ADI_MIN_LENGTH) {
+		printk(KERN_WARNING "adi: Bad data packet length (%d).\n", adi->length);
+		adi->length = 0;
+		return;
+	}
+
+	adi->axes8 = adi_get_bits(adi, 4);
+	adi->buttons = adi_get_bits(adi, 6);
+
+	if (adi_get_bits(adi, 6) != 8 && adi->hats) {
+		printk(KERN_WARNING "adi: Other than 8-dir POVs not supported yet.\n");
+		adi->length = 0;
+		return;
+	}
+
+	adi->buttons += adi_get_bits(adi, 6);
+	adi->hats += adi_get_bits(adi, 4);
+
+	i = adi_get_bits(adi, 4);
+
+	if (t & ADI_FLAG_10BIT) {
+		adi->axes10 = adi->axes8 - i;
+		adi->axes8 = i;
+	}
+
+	t = adi_get_bits(adi, 4);
+
+	for (i = 0; i < t; i++)
+		adi->cname[i] = adi_get_bits(adi, 8);
+	adi->cname[i] = 0;
+
+	t = 8 + adi->buttons + adi->axes10 * 10 + adi->axes8 * 8 + adi->hats * 4;
+	if (adi->length != t && adi->length != t + (t & 1)) {
+		printk(KERN_WARNING "adi: Expected length %d != data length %d\n", t, adi->length);
+		adi->length = 0;
+		return;
+	}
+
+	switch (adi->id) {
+		case ADI_ID_TPD:
+			adi->pad = 4;
+			adi->buttons -= 4;
+			break;
+		case ADI_ID_WGP:
+			adi->pad = 0;
+			adi->buttons -= 4;
+			break;
+		default:
+			adi->pad = -1;
+			break;
+	}
+}
+
+static int adi_init_input(struct adi *adi, struct adi_port *port, int half)
+{
+	struct input_dev *input_dev;
+	char buf[ADI_MAX_NAME_LENGTH];
+	int i, t;
+
+	adi->dev = input_dev = input_allocate_device();
+	if (!input_dev)
+		return -ENOMEM;
+
+	t = adi->id < ADI_ID_MAX ? adi->id : ADI_ID_MAX;
+
+	snprintf(buf, ADI_MAX_PHYS_LENGTH, adi_names[t], adi->id);
+	snprintf(adi->name, ADI_MAX_NAME_LENGTH, "Logitech %s [%s]", buf, adi->cname);
+	snprintf(adi->phys, ADI_MAX_PHYS_LENGTH, "%s/input%d", port->gameport->phys, half);
+
+	adi->abs = adi_abs[t];
+	adi->key = adi_key[t];
+
+	input_dev->name = adi->name;
+	input_dev->phys = adi->phys;
+	input_dev->id.bustype = BUS_GAMEPORT;
+	input_dev->id.vendor = GAMEPORT_ID_VENDOR_LOGITECH;
+	input_dev->id.product = adi->id;
+	input_dev->id.version = 0x0100;
+	input_dev->dev.parent = &port->gameport->dev;
+
+	input_set_drvdata(input_dev, port);
+
+	input_dev->open = adi_open;
+	input_dev->close = adi_close;
+
+	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
+
+	for (i = 0; i < adi->axes10 + adi->axes8 + (adi->hats + (adi->pad != -1)) * 2; i++)
+		set_bit(adi->abs[i], input_dev->absbit);
+
+	for (i = 0; i < adi->buttons; i++)
+		set_bit(adi->key[i], input_dev->keybit);
+
+	return 0;
+}
+
+static void adi_init_center(struct adi *adi)
+{
+	int i, t, x;
+
+	if (!adi->length)
+		return;
+
+	for (i = 0; i < adi->axes10 + adi->axes8 + (adi->hats + (adi->pad != -1)) * 2; i++) {
+
+		t = adi->abs[i];
+		x = input_abs_get_val(adi->dev, t);
+
+		if (t == ABS_THROTTLE || t == ABS_RUDDER || adi->id == ADI_ID_WGPE)
+			x = i < adi->axes10 ? 512 : 128;
+
+		if (i < adi->axes10)
+			input_set_abs_params(adi->dev, t, 64, x * 2 - 64, 2, 16);
+		else if (i < adi->axes10 + adi->axes8)
+			input_set_abs_params(adi->dev, t, 48, x * 2 - 48, 1, 16);
+		else
+			input_set_abs_params(adi->dev, t, -1, 1, 0, 0);
+	}
+}
+
+/*
+ * adi_connect() probes for Logitech ADI joysticks.
+ */
+
+static int adi_connect(struct gameport *gameport, struct gameport_driver *drv)
+{
+	struct adi_port *port;
+	int i;
+	int err;
+
+	port = kzalloc_obj(*port);
+	if (!port)
+		return -ENOMEM;
+
+	port->gameport = gameport;
+
+	gameport_set_drvdata(gameport, port);
+
+	err = gameport_open(gameport, drv, GAMEPORT_MODE_RAW);
+	if (err)
+		goto fail1;
+
+	adi_init_digital(gameport);
+	adi_read_packet(port);
+
+	if (port->adi[0].ret >= ADI_MIN_LEN_LENGTH)
+		adi_move_bits(port, adi_get_bits(port->adi, 10));
+
+	for (i = 0; i < 2; i++) {
+		adi_id_decode(port->adi + i, port);
+
+		if (!port->adi[i].length)
+			continue;
+
+		err = adi_init_input(port->adi + i, port, i);
+		if (err)
+			goto fail2;
+	}
+
+	if (!port->adi[0].length && !port->adi[1].length) {
+		err = -ENODEV;
+		goto fail2;
+	}
+
+	gameport_set_poll_handler(gameport, adi_poll);
+	gameport_set_poll_interval(gameport, 20);
+
+	msleep(ADI_INIT_DELAY);
+	if (adi_read(port)) {
+		msleep(ADI_DATA_DELAY);
+		adi_read(port);
+	}
+
+	for (i = 0; i < 2; i++)
+		if (port->adi[i].length > 0) {
+			adi_init_center(port->adi + i);
+			err = input_register_device(port->adi[i].dev);
+			if (err)
+				goto fail3;
+		}
+
+	return 0;
+
+ fail3: while (--i >= 0) {
+		if (port->adi[i].length > 0) {
+			input_unregister_device(port->adi[i].dev);
+			port->adi[i].dev = NULL;
+		}
+	}
+ fail2:	for (i = 0; i < 2; i++)
+		input_free_device(port->adi[i].dev);
+	gameport_close(gameport);
+ fail1:	gameport_set_drvdata(gameport, NULL);
+	kfree(port);
+	return err;
+}
+
+static void adi_disconnect(struct gameport *gameport)
+{
+	int i;
+	struct adi_port *port = gameport_get_drvdata(gameport);
+
+	for (i = 0; i < 2; i++)
+		if (port->adi[i].length > 0)
+			input_unregister_device(port->adi[i].dev);
+	gameport_close(gameport);
+	gameport_set_drvdata(gameport, NULL);
+	kfree(port);
+}
+
+static struct gameport_driver adi_drv = {
+	.driver		= {
+		.name	= "adi",
+	},
+	.description	= DRIVER_DESC,
+	.connect	= adi_connect,
+	.disconnect	= adi_disconnect,
+};
+
+module_gameport_driver(adi_drv);