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, 175 insertions, 0 deletions

diff --git a/drivers/hid/hid-roccat-common.c b/drivers/hid/hid-roccat-common.c
new file mode 100644
index 000000000..4465ef95d
--- /dev/null
+++ b/drivers/hid/hid-roccat-common.c
@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Roccat common functions for device specific drivers
+ *
+ * Copyright (c) 2011 Stefan Achatz <erazor_de@users.sourceforge.net>
+ */
+
+/*
+ */
+
+#include <linux/hid.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include "hid-roccat-common.h"
+
+static inline uint16_t roccat_common2_feature_report(uint8_t report_id)
+{
+	return 0x300 | report_id;
+}
+
+int roccat_common2_receive(struct usb_device *usb_dev, uint report_id,
+		void *data, uint size)
+{
+	char *buf;
+	int len;
+
+	buf = kmalloc(size, GFP_KERNEL);
+	if (buf == NULL)
+		return -ENOMEM;
+
+	len = usb_control_msg(usb_dev, usb_rcvctrlpipe(usb_dev, 0),
+			HID_REQ_GET_REPORT,
+			USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_IN,
+			roccat_common2_feature_report(report_id),
+			0, buf, size, USB_CTRL_SET_TIMEOUT);
+
+	memcpy(data, buf, size);
+	kfree(buf);
+	return ((len < 0) ? len : ((len != size) ? -EIO : 0));
+}
+EXPORT_SYMBOL_GPL(roccat_common2_receive);
+
+int roccat_common2_send(struct usb_device *usb_dev, uint report_id,
+		void const *data, uint size)
+{
+	char *buf;
+	int len;
+
+	buf = kmemdup(data, size, GFP_KERNEL);
+	if (buf == NULL)
+		return -ENOMEM;
+
+	len = usb_control_msg(usb_dev, usb_sndctrlpipe(usb_dev, 0),
+			HID_REQ_SET_REPORT,
+			USB_TYPE_CLASS | USB_RECIP_INTERFACE | USB_DIR_OUT,
+			roccat_common2_feature_report(report_id),
+			0, buf, size, USB_CTRL_SET_TIMEOUT);
+
+	kfree(buf);
+	return ((len < 0) ? len : ((len != size) ? -EIO : 0));
+}
+EXPORT_SYMBOL_GPL(roccat_common2_send);
+
+enum roccat_common2_control_states {
+	ROCCAT_COMMON_CONTROL_STATUS_CRITICAL = 0,
+	ROCCAT_COMMON_CONTROL_STATUS_OK = 1,
+	ROCCAT_COMMON_CONTROL_STATUS_INVALID = 2,
+	ROCCAT_COMMON_CONTROL_STATUS_BUSY = 3,
+	ROCCAT_COMMON_CONTROL_STATUS_CRITICAL_NEW = 4,
+};
+
+static int roccat_common2_receive_control_status(struct usb_device *usb_dev)
+{
+	int retval;
+	struct roccat_common2_control control;
+
+	do {
+		msleep(50);
+		retval = roccat_common2_receive(usb_dev,
+				ROCCAT_COMMON_COMMAND_CONTROL,
+				&control, sizeof(struct roccat_common2_control));
+
+		if (retval)
+			return retval;
+
+		switch (control.value) {
+		case ROCCAT_COMMON_CONTROL_STATUS_OK:
+			return 0;
+		case ROCCAT_COMMON_CONTROL_STATUS_BUSY:
+			msleep(500);
+			continue;
+		case ROCCAT_COMMON_CONTROL_STATUS_INVALID:
+		case ROCCAT_COMMON_CONTROL_STATUS_CRITICAL:
+		case ROCCAT_COMMON_CONTROL_STATUS_CRITICAL_NEW:
+			return -EINVAL;
+		default:
+			dev_err(&usb_dev->dev,
+					"roccat_common2_receive_control_status: "
+					"unknown response value 0x%x\n",
+					control.value);
+			return -EINVAL;
+		}
+
+	} while (1);
+}
+
+int roccat_common2_send_with_status(struct usb_device *usb_dev,
+		uint command, void const *buf, uint size)
+{
+	int retval;
+
+	retval = roccat_common2_send(usb_dev, command, buf, size);
+	if (retval)
+		return retval;
+
+	msleep(100);
+
+	return roccat_common2_receive_control_status(usb_dev);
+}
+EXPORT_SYMBOL_GPL(roccat_common2_send_with_status);
+
+int roccat_common2_device_init_struct(struct usb_device *usb_dev,
+		struct roccat_common2_device *dev)
+{
+	mutex_init(&dev->lock);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(roccat_common2_device_init_struct);
+
+ssize_t roccat_common2_sysfs_read(struct file *fp, struct kobject *kobj,
+		char *buf, loff_t off, size_t count,
+		size_t real_size, uint command)
+{
+	struct device *dev = kobj_to_dev(kobj)->parent->parent;
+	struct roccat_common2_device *roccat_dev = hid_get_drvdata(dev_get_drvdata(dev));
+	struct usb_device *usb_dev = interface_to_usbdev(to_usb_interface(dev));
+	int retval;
+
+	if (off >= real_size)
+		return 0;
+
+	if (off != 0 || count != real_size)
+		return -EINVAL;
+
+	mutex_lock(&roccat_dev->lock);
+	retval = roccat_common2_receive(usb_dev, command, buf, real_size);
+	mutex_unlock(&roccat_dev->lock);
+
+	return retval ? retval : real_size;
+}
+EXPORT_SYMBOL_GPL(roccat_common2_sysfs_read);
+
+ssize_t roccat_common2_sysfs_write(struct file *fp, struct kobject *kobj,
+		void const *buf, loff_t off, size_t count,
+		size_t real_size, uint command)
+{
+	struct device *dev = kobj_to_dev(kobj)->parent->parent;
+	struct roccat_common2_device *roccat_dev = hid_get_drvdata(dev_get_drvdata(dev));
+	struct usb_device *usb_dev = interface_to_usbdev(to_usb_interface(dev));
+	int retval;
+
+	if (off != 0 || count != real_size)
+		return -EINVAL;
+
+	mutex_lock(&roccat_dev->lock);
+	retval = roccat_common2_send_with_status(usb_dev, command, buf, real_size);
+	mutex_unlock(&roccat_dev->lock);
+
+	return retval ? retval : real_size;
+}
+EXPORT_SYMBOL_GPL(roccat_common2_sysfs_write);
+
+MODULE_AUTHOR("Stefan Achatz");
+MODULE_DESCRIPTION("USB Roccat common driver");
+MODULE_LICENSE("GPL v2");