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, 369 insertions, 0 deletions

diff --git a/drivers/hid/hid-appleir.c b/drivers/hid/hid-appleir.c
new file mode 100644
index 000000000..adaa44a85
--- /dev/null
+++ b/drivers/hid/hid-appleir.c
@@ -0,0 +1,369 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * HID driver for the apple ir device
+ *
+ * Original driver written by James McKenzie
+ * Ported to recent 2.6 kernel versions by Greg Kroah-Hartman <gregkh@suse.de>
+ * Updated to support newer remotes by Bastien Nocera <hadess@hadess.net>
+ * Ported to HID subsystem by Benjamin Tissoires <benjamin.tissoires@gmail.com>
+ *
+ * Copyright (C) 2006 James McKenzie
+ * Copyright (C) 2008 Greg Kroah-Hartman <greg@kroah.com>
+ * Copyright (C) 2008 Novell Inc.
+ * Copyright (C) 2010, 2012 Bastien Nocera <hadess@hadess.net>
+ * Copyright (C) 2013 Benjamin Tissoires <benjamin.tissoires@gmail.com>
+ * Copyright (C) 2013 Red Hat Inc. All Rights Reserved
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+#include "hid-ids.h"
+
+MODULE_AUTHOR("James McKenzie");
+MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@redhat.com>");
+MODULE_DESCRIPTION("HID Apple IR remote controls");
+MODULE_LICENSE("GPL");
+
+#define KEY_MASK		0x0F
+#define TWO_PACKETS_MASK	0x40
+
+/*
+ * James McKenzie has two devices both of which report the following
+ * 25 87 ee 83 0a	+
+ * 25 87 ee 83 0c	-
+ * 25 87 ee 83 09	<<
+ * 25 87 ee 83 06	>>
+ * 25 87 ee 83 05	>"
+ * 25 87 ee 83 03	menu
+ * 26 00 00 00 00	for key repeat
+ */
+
+/*
+ * Thomas Glanzmann reports the following responses
+ * 25 87 ee ca 0b	+
+ * 25 87 ee ca 0d	-
+ * 25 87 ee ca 08	<<
+ * 25 87 ee ca 07	>>
+ * 25 87 ee ca 04	>"
+ * 25 87 ee ca 02	menu
+ * 26 00 00 00 00       for key repeat
+ *
+ * He also observes the following event sometimes
+ * sent after a key is release, which I interpret
+ * as a flat battery message
+ * 25 87 e0 ca 06	flat battery
+ */
+
+/*
+ * Alexandre Karpenko reports the following responses for Device ID 0x8242
+ * 25 87 ee 47 0b	+
+ * 25 87 ee 47 0d	-
+ * 25 87 ee 47 08	<<
+ * 25 87 ee 47 07	>>
+ * 25 87 ee 47 04	>"
+ * 25 87 ee 47 02	menu
+ * 26 87 ee 47 **	for key repeat (** is the code of the key being held)
+ */
+
+/*
+ * Bastien Nocera's remote
+ * 25 87 ee 91 5f	followed by
+ * 25 87 ee 91 05	gives you >"
+ *
+ * 25 87 ee 91 5c	followed by
+ * 25 87 ee 91 05	gives you the middle button
+ */
+
+/*
+ * Fabien Andre's remote
+ * 25 87 ee a3 5e	followed by
+ * 25 87 ee a3 04	gives you >"
+ *
+ * 25 87 ee a3 5d	followed by
+ * 25 87 ee a3 04	gives you the middle button
+ */
+
+static const unsigned short appleir_key_table[] = {
+	KEY_RESERVED,
+	KEY_MENU,
+	KEY_PLAYPAUSE,
+	KEY_FORWARD,
+	KEY_BACK,
+	KEY_VOLUMEUP,
+	KEY_VOLUMEDOWN,
+	KEY_RESERVED,
+	KEY_RESERVED,
+	KEY_RESERVED,
+	KEY_RESERVED,
+	KEY_RESERVED,
+	KEY_RESERVED,
+	KEY_RESERVED,
+	KEY_ENTER,
+	KEY_PLAYPAUSE,
+	KEY_RESERVED,
+};
+
+struct appleir {
+	struct input_dev *input_dev;
+	struct hid_device *hid;
+	unsigned short keymap[ARRAY_SIZE(appleir_key_table)];
+	struct timer_list key_up_timer;	/* timer for key up */
+	spinlock_t lock;		/* protects .current_key, .removing */
+	int current_key;		/* the currently pressed key */
+	int prev_key_idx;		/* key index in a 2 packets message */
+	bool removing;			/* set during teardown; gates input_dev access */
+};
+
+static int get_key(int data)
+{
+	/*
+	 * The key is coded accross bits 2..9:
+	 *
+	 * 0x00 or 0x01 (        )	key:  0		-> KEY_RESERVED
+	 * 0x02 or 0x03 (  menu  )	key:  1		-> KEY_MENU
+	 * 0x04 or 0x05 (   >"   )	key:  2		-> KEY_PLAYPAUSE
+	 * 0x06 or 0x07 (   >>   )	key:  3		-> KEY_FORWARD
+	 * 0x08 or 0x09 (   <<   )	key:  4		-> KEY_BACK
+	 * 0x0a or 0x0b (    +   )	key:  5		-> KEY_VOLUMEUP
+	 * 0x0c or 0x0d (    -   )	key:  6		-> KEY_VOLUMEDOWN
+	 * 0x0e or 0x0f (        )	key:  7		-> KEY_RESERVED
+	 * 0x50 or 0x51 (        )	key:  8		-> KEY_RESERVED
+	 * 0x52 or 0x53 (        )	key:  9		-> KEY_RESERVED
+	 * 0x54 or 0x55 (        )	key: 10		-> KEY_RESERVED
+	 * 0x56 or 0x57 (        )	key: 11		-> KEY_RESERVED
+	 * 0x58 or 0x59 (        )	key: 12		-> KEY_RESERVED
+	 * 0x5a or 0x5b (        )	key: 13		-> KEY_RESERVED
+	 * 0x5c or 0x5d ( middle )	key: 14		-> KEY_ENTER
+	 * 0x5e or 0x5f (   >"   )	key: 15		-> KEY_PLAYPAUSE
+	 *
+	 * Packets starting with 0x5 are part of a two-packets message,
+	 * we notify the caller by sending a negative value.
+	 */
+	int key = (data >> 1) & KEY_MASK;
+
+	if ((data & TWO_PACKETS_MASK))
+		/* Part of a 2 packets-command */
+		key = -key;
+
+	return key;
+}
+
+static void key_up(struct hid_device *hid, struct appleir *appleir, int key)
+{
+	input_report_key(appleir->input_dev, key, 0);
+	input_sync(appleir->input_dev);
+}
+
+static void key_down(struct hid_device *hid, struct appleir *appleir, int key)
+{
+	input_report_key(appleir->input_dev, key, 1);
+	input_sync(appleir->input_dev);
+}
+
+static void battery_flat(struct appleir *appleir)
+{
+	dev_err(&appleir->input_dev->dev, "possible flat battery?\n");
+}
+
+static void key_up_tick(struct timer_list *t)
+{
+	struct appleir *appleir = timer_container_of(appleir, t, key_up_timer);
+	struct hid_device *hid = appleir->hid;
+	unsigned long flags;
+
+	spin_lock_irqsave(&appleir->lock, flags);
+	if (!appleir->removing && appleir->current_key) {
+		key_up(hid, appleir, appleir->current_key);
+		appleir->current_key = 0;
+	}
+	spin_unlock_irqrestore(&appleir->lock, flags);
+}
+
+static int appleir_raw_event(struct hid_device *hid, struct hid_report *report,
+	 u8 *data, int len)
+{
+	struct appleir *appleir = hid_get_drvdata(hid);
+	static const u8 keydown[] = { 0x25, 0x87, 0xee };
+	static const u8 keyrepeat[] = { 0x26, };
+	static const u8 flatbattery[] = { 0x25, 0x87, 0xe0 };
+	unsigned long flags;
+
+	if (len != 5 || !(hid->claimed & HID_CLAIMED_INPUT))
+		goto out;
+
+	if (!memcmp(data, keydown, sizeof(keydown))) {
+		int index;
+
+		spin_lock_irqsave(&appleir->lock, flags);
+		if (appleir->removing) {
+			spin_unlock_irqrestore(&appleir->lock, flags);
+			goto out;
+		}
+		/*
+		 * If we already have a key down, take it up before marking
+		 * this one down
+		 */
+		if (appleir->current_key)
+			key_up(hid, appleir, appleir->current_key);
+
+		/* Handle dual packet commands */
+		if (appleir->prev_key_idx > 0)
+			index = appleir->prev_key_idx;
+		else
+			index = get_key(data[4]);
+
+		if (index >= 0) {
+			appleir->current_key = appleir->keymap[index];
+
+			key_down(hid, appleir, appleir->current_key);
+			/*
+			 * Remote doesn't do key up, either pull them up, in
+			 * the test above, or here set a timer which pulls
+			 * them up after 1/8 s
+			 */
+			mod_timer(&appleir->key_up_timer, jiffies + HZ / 8);
+			appleir->prev_key_idx = 0;
+		} else
+			/* Remember key for next packet */
+			appleir->prev_key_idx = -index;
+		spin_unlock_irqrestore(&appleir->lock, flags);
+		goto out;
+	}
+
+	appleir->prev_key_idx = 0;
+
+	if (!memcmp(data, keyrepeat, sizeof(keyrepeat))) {
+		spin_lock_irqsave(&appleir->lock, flags);
+		if (!appleir->removing) {
+			key_down(hid, appleir, appleir->current_key);
+			/*
+			 * Remote doesn't do key up, either pull them up, in
+			 * the test above, or here set a timer which pulls them
+			 * up after 1/8 s
+			 */
+			mod_timer(&appleir->key_up_timer, jiffies + HZ / 8);
+		}
+		spin_unlock_irqrestore(&appleir->lock, flags);
+		goto out;
+	}
+
+	if (!memcmp(data, flatbattery, sizeof(flatbattery))) {
+		spin_lock_irqsave(&appleir->lock, flags);
+		if (!appleir->removing)
+			battery_flat(appleir);
+		spin_unlock_irqrestore(&appleir->lock, flags);
+		/* Fall through */
+	}
+
+out:
+	/* let hidraw and hiddev handle the report */
+	return 0;
+}
+
+static int appleir_input_configured(struct hid_device *hid,
+		struct hid_input *hidinput)
+{
+	struct input_dev *input_dev = hidinput->input;
+	struct appleir *appleir = hid_get_drvdata(hid);
+	int i;
+
+	appleir->input_dev = input_dev;
+
+	input_dev->keycode = appleir->keymap;
+	input_dev->keycodesize = sizeof(unsigned short);
+	input_dev->keycodemax = ARRAY_SIZE(appleir->keymap);
+
+	input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_REP);
+
+	memcpy(appleir->keymap, appleir_key_table, sizeof(appleir->keymap));
+	for (i = 0; i < ARRAY_SIZE(appleir_key_table); i++)
+		set_bit(appleir->keymap[i], input_dev->keybit);
+	clear_bit(KEY_RESERVED, input_dev->keybit);
+
+	return 0;
+}
+
+static int appleir_input_mapping(struct hid_device *hid,
+		struct hid_input *hi, struct hid_field *field,
+		struct hid_usage *usage, unsigned long **bit, int *max)
+{
+	return -1;
+}
+
+static int appleir_probe(struct hid_device *hid, const struct hid_device_id *id)
+{
+	int ret;
+	struct appleir *appleir;
+
+	appleir = devm_kzalloc(&hid->dev, sizeof(struct appleir), GFP_KERNEL);
+	if (!appleir)
+		return -ENOMEM;
+
+	appleir->hid = hid;
+
+	/* force input as some remotes bypass the input registration */
+	hid->quirks |= HID_QUIRK_HIDINPUT_FORCE;
+
+	spin_lock_init(&appleir->lock);
+	timer_setup(&appleir->key_up_timer, key_up_tick, 0);
+
+	hid_set_drvdata(hid, appleir);
+
+	ret = hid_parse(hid);
+	if (ret) {
+		hid_err(hid, "parse failed\n");
+		goto fail;
+	}
+
+	ret = hid_hw_start(hid, HID_CONNECT_DEFAULT | HID_CONNECT_HIDDEV_FORCE);
+	if (ret) {
+		hid_err(hid, "hw start failed\n");
+		goto fail;
+	}
+
+	return 0;
+fail:
+	devm_kfree(&hid->dev, appleir);
+	return ret;
+}
+
+static void appleir_remove(struct hid_device *hid)
+{
+	struct appleir *appleir = hid_get_drvdata(hid);
+	unsigned long flags;
+
+	/*
+	 * Mark the driver as tearing down so that any concurrent raw_event
+	 * (e.g. from a USB URB completion that hid_hw_stop() has not yet
+	 * killed) and the key_up_timer softirq stop touching input_dev
+	 * before hid_hw_stop() frees it via hidinput_disconnect().
+	 */
+	spin_lock_irqsave(&appleir->lock, flags);
+	appleir->removing = true;
+	spin_unlock_irqrestore(&appleir->lock, flags);
+
+	timer_shutdown_sync(&appleir->key_up_timer);
+	hid_hw_stop(hid);
+}
+
+static const struct hid_device_id appleir_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_IRCONTROL) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_IRCONTROL2) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_IRCONTROL3) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_IRCONTROL4) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_APPLE, USB_DEVICE_ID_APPLE_IRCONTROL5) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, appleir_devices);
+
+static struct hid_driver appleir_driver = {
+	.name = "appleir",
+	.id_table = appleir_devices,
+	.raw_event = appleir_raw_event,
+	.input_configured = appleir_input_configured,
+	.probe = appleir_probe,
+	.remove = appleir_remove,
+	.input_mapping = appleir_input_mapping,
+};
+module_hid_driver(appleir_driver);