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, 192 insertions, 0 deletions

diff --git a/drivers/hid/hid-cypress.c b/drivers/hid/hid-cypress.c
new file mode 100644
index 000000000..f18fddc17
--- /dev/null
+++ b/drivers/hid/hid-cypress.c
@@ -0,0 +1,192 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  HID driver for some cypress "special" devices
+ *
+ *  Copyright (c) 1999 Andreas Gal
+ *  Copyright (c) 2000-2005 Vojtech Pavlik <vojtech@suse.cz>
+ *  Copyright (c) 2005 Michael Haboustak <mike-@cinci.rr.com> for Concept2, Inc
+ *  Copyright (c) 2006-2007 Jiri Kosina
+ *  Copyright (c) 2008 Jiri Slaby
+ */
+
+/*
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/input.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+#define CP_RDESC_SWAPPED_MIN_MAX	0x01
+#define CP_2WHEEL_MOUSE_HACK		0x02
+#define CP_2WHEEL_MOUSE_HACK_ON		0x04
+
+#define VA_INVAL_LOGICAL_BOUNDARY	0x08
+
+struct cp_device {
+	unsigned long quirks;
+};
+
+/*
+ * Some USB barcode readers from cypress have usage min and usage max in
+ * the wrong order
+ */
+static __u8 *cp_rdesc_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
+{
+	unsigned int i;
+
+	if (*rsize < 4)
+		return rdesc;
+
+	for (i = 0; i < *rsize - 4; i++)
+		if (rdesc[i] == 0x29 && rdesc[i + 2] == 0x19) {
+			rdesc[i] = 0x19;
+			rdesc[i + 2] = 0x29;
+			swap(rdesc[i + 3], rdesc[i + 1]);
+		}
+	return rdesc;
+}
+
+static __u8 *va_logical_boundary_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
+{
+	/*
+	 * Varmilo VA104M (with VID Cypress and device ID 07B1) incorrectly
+	 * reports Logical Minimum of its Consumer Control device as 572
+	 * (0x02 0x3c). Fix this by setting its Logical Minimum to zero.
+	 */
+	if (*rsize == 25 &&
+			rdesc[0] == 0x05 && rdesc[1] == 0x0c &&
+			rdesc[2] == 0x09 && rdesc[3] == 0x01 &&
+			rdesc[6] == 0x19 && rdesc[7] == 0x00 &&
+			rdesc[11] == 0x16 && rdesc[12] == 0x3c && rdesc[13] == 0x02) {
+		hid_info(hdev,
+			 "fixing up varmilo VA104M consumer control report descriptor\n");
+		rdesc[12] = 0x00;
+		rdesc[13] = 0x00;
+	}
+	return rdesc;
+}
+
+static const __u8 *cp_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
+{
+	const struct cp_device *cp_device = hid_get_drvdata(hdev);
+	unsigned long quirks = cp_device->quirks;
+
+	if (quirks & CP_RDESC_SWAPPED_MIN_MAX)
+		rdesc = cp_rdesc_fixup(hdev, rdesc, rsize);
+	if (quirks & VA_INVAL_LOGICAL_BOUNDARY)
+		rdesc = va_logical_boundary_fixup(hdev, rdesc, rsize);
+
+	return rdesc;
+}
+
+static int cp_input_mapped(struct hid_device *hdev, struct hid_input *hi,
+		struct hid_field *field, struct hid_usage *usage,
+		unsigned long **bit, int *max)
+{
+	const struct cp_device *cp_device = hid_get_drvdata(hdev);
+	unsigned long quirks = cp_device->quirks;
+
+	if (!(quirks & CP_2WHEEL_MOUSE_HACK))
+		return 0;
+
+	if (usage->type == EV_REL && usage->code == REL_WHEEL)
+		set_bit(REL_HWHEEL, *bit);
+	if (usage->hid == 0x00090005)
+		return -1;
+
+	return 0;
+}
+
+static int cp_event(struct hid_device *hdev, struct hid_field *field,
+		struct hid_usage *usage, __s32 value)
+{
+	struct cp_device *cp_device = hid_get_drvdata(hdev);
+
+	if (!(hdev->claimed & HID_CLAIMED_INPUT) || !field->hidinput ||
+			!usage->type || !(cp_device->quirks & CP_2WHEEL_MOUSE_HACK))
+		return 0;
+
+	if (usage->hid == 0x00090005) {
+		if (value)
+			cp_device->quirks |= CP_2WHEEL_MOUSE_HACK_ON;
+		else
+			cp_device->quirks &= ~CP_2WHEEL_MOUSE_HACK_ON;
+		return 1;
+	}
+
+	if (usage->code == REL_WHEEL && (cp_device->quirks & CP_2WHEEL_MOUSE_HACK_ON)) {
+		struct input_dev *input = field->hidinput->input;
+
+		input_event(input, usage->type, REL_HWHEEL, value);
+		return 1;
+	}
+
+	return 0;
+}
+
+static int cp_probe(struct hid_device *hdev, const struct hid_device_id *id)
+{
+	int ret;
+	struct cp_device *cp_device;
+
+	cp_device = devm_kzalloc(&hdev->dev, sizeof(*cp_device), GFP_KERNEL);
+
+	if (!cp_device)
+		return -ENOMEM;
+
+	cp_device->quirks = id->driver_data;
+
+	hid_set_drvdata(hdev, cp_device);
+
+	ret = hid_parse(hdev);
+	if (ret) {
+		hid_err(hdev, "parse failed\n");
+		goto err_free;
+	}
+
+	ret = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+	if (ret) {
+		hid_err(hdev, "hw start failed\n");
+		goto err_free;
+	}
+
+	return 0;
+err_free:
+	return ret;
+}
+
+static const struct hid_device_id cp_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_BARCODE_1),
+		.driver_data = CP_RDESC_SWAPPED_MIN_MAX },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_BARCODE_2),
+		.driver_data = CP_RDESC_SWAPPED_MIN_MAX },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_BARCODE_3),
+		.driver_data = CP_RDESC_SWAPPED_MIN_MAX },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_BARCODE_4),
+		.driver_data = CP_RDESC_SWAPPED_MIN_MAX },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_MOUSE),
+		.driver_data = CP_2WHEEL_MOUSE_HACK },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_CYPRESS, USB_DEVICE_ID_CYPRESS_VARMILO_VA104M_07B1),
+		.driver_data = VA_INVAL_LOGICAL_BOUNDARY },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, cp_devices);
+
+static struct hid_driver cp_driver = {
+	.name = "cypress",
+	.id_table = cp_devices,
+	.report_fixup = cp_report_fixup,
+	.input_mapped = cp_input_mapped,
+	.event = cp_event,
+	.probe = cp_probe,
+};
+module_hid_driver(cp_driver);
+
+MODULE_DESCRIPTION("HID driver for some cypress \"special\" devices");
+MODULE_LICENSE("GPL");