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, 476 insertions, 0 deletions

diff --git a/drivers/usb/misc/lvstest.c b/drivers/usb/misc/lvstest.c
new file mode 100644
index 000000000..9b6e10177
--- /dev/null
+++ b/drivers/usb/misc/lvstest.c
@@ -0,0 +1,476 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * drivers/usb/misc/lvstest.c
+ *
+ * Test pattern generation for Link Layer Validation System Tests
+ *
+ * Copyright (C) 2014 ST Microelectronics
+ * Pratyush Anand <pratyush.anand@gmail.com>
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/usb/ch11.h>
+#include <linux/usb/hcd.h>
+#include <linux/usb/phy.h>
+
+struct lvs_rh {
+	/* root hub interface */
+	struct usb_interface *intf;
+	/* if lvs device connected */
+	bool present;
+	/* port no at which lvs device is present */
+	int portnum;
+	/* urb buffer */
+	u8 buffer[8];
+	/* class descriptor */
+	struct usb_hub_descriptor descriptor;
+	/* urb for polling interrupt pipe */
+	struct urb *urb;
+	/* LVH RH work */
+	struct work_struct	rh_work;
+	/* RH port status */
+	struct usb_port_status port_status;
+};
+
+static struct usb_device *create_lvs_device(struct usb_interface *intf)
+{
+	struct usb_device *udev, *hdev;
+	struct usb_hcd *hcd;
+	struct lvs_rh *lvs = usb_get_intfdata(intf);
+
+	if (!lvs->present) {
+		dev_err(&intf->dev, "No LVS device is present\n");
+		return NULL;
+	}
+
+	hdev = interface_to_usbdev(intf);
+	hcd = bus_to_hcd(hdev->bus);
+
+	udev = usb_alloc_dev(hdev, hdev->bus, lvs->portnum);
+	if (!udev) {
+		dev_err(&intf->dev, "Could not allocate lvs udev\n");
+		return NULL;
+	}
+	udev->speed = USB_SPEED_SUPER;
+	udev->ep0.desc.wMaxPacketSize = cpu_to_le16(512);
+	usb_set_device_state(udev, USB_STATE_DEFAULT);
+
+	if (hcd->driver->enable_device) {
+		if (hcd->driver->enable_device(hcd, udev) < 0) {
+			dev_err(&intf->dev, "Failed to enable\n");
+			usb_put_dev(udev);
+			return NULL;
+		}
+	}
+
+	return udev;
+}
+
+static void destroy_lvs_device(struct usb_device *udev)
+{
+	struct usb_device *hdev = udev->parent;
+	struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
+
+	if (hcd->driver->free_dev)
+		hcd->driver->free_dev(hcd, udev);
+
+	usb_put_dev(udev);
+}
+
+static int lvs_rh_clear_port_feature(struct usb_device *hdev,
+		int port1, int feature)
+{
+	return usb_control_msg(hdev, usb_sndctrlpipe(hdev, 0),
+		USB_REQ_CLEAR_FEATURE, USB_RT_PORT, feature, port1,
+		NULL, 0, 1000);
+}
+
+static int lvs_rh_set_port_feature(struct usb_device *hdev,
+		int port1, int feature)
+{
+	return usb_control_msg(hdev, usb_sndctrlpipe(hdev, 0),
+		USB_REQ_SET_FEATURE, USB_RT_PORT, feature, port1,
+		NULL, 0, 1000);
+}
+
+static ssize_t u3_entry_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct usb_device *hdev = interface_to_usbdev(intf);
+	struct lvs_rh *lvs = usb_get_intfdata(intf);
+	struct usb_device *udev;
+	int ret;
+
+	udev = create_lvs_device(intf);
+	if (!udev) {
+		dev_err(dev, "failed to create lvs device\n");
+		return -ENOMEM;
+	}
+
+	ret = lvs_rh_set_port_feature(hdev, lvs->portnum,
+			USB_PORT_FEAT_SUSPEND);
+	if (ret < 0)
+		dev_err(dev, "can't issue U3 entry %d\n", ret);
+
+	destroy_lvs_device(udev);
+
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+static DEVICE_ATTR_WO(u3_entry);
+
+static ssize_t u3_exit_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct usb_device *hdev = interface_to_usbdev(intf);
+	struct lvs_rh *lvs = usb_get_intfdata(intf);
+	struct usb_device *udev;
+	int ret;
+
+	udev = create_lvs_device(intf);
+	if (!udev) {
+		dev_err(dev, "failed to create lvs device\n");
+		return -ENOMEM;
+	}
+
+	ret = lvs_rh_clear_port_feature(hdev, lvs->portnum,
+			USB_PORT_FEAT_SUSPEND);
+	if (ret < 0)
+		dev_err(dev, "can't issue U3 exit %d\n", ret);
+
+	destroy_lvs_device(udev);
+
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+static DEVICE_ATTR_WO(u3_exit);
+
+static ssize_t hot_reset_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct usb_device *hdev = interface_to_usbdev(intf);
+	struct lvs_rh *lvs = usb_get_intfdata(intf);
+	int ret;
+
+	ret = lvs_rh_set_port_feature(hdev, lvs->portnum,
+			USB_PORT_FEAT_RESET);
+	if (ret < 0) {
+		dev_err(dev, "can't issue hot reset %d\n", ret);
+		return ret;
+	}
+
+	return count;
+}
+static DEVICE_ATTR_WO(hot_reset);
+
+static ssize_t warm_reset_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct usb_device *hdev = interface_to_usbdev(intf);
+	struct lvs_rh *lvs = usb_get_intfdata(intf);
+	int ret;
+
+	ret = lvs_rh_set_port_feature(hdev, lvs->portnum,
+			USB_PORT_FEAT_BH_PORT_RESET);
+	if (ret < 0) {
+		dev_err(dev, "can't issue warm reset %d\n", ret);
+		return ret;
+	}
+
+	return count;
+}
+static DEVICE_ATTR_WO(warm_reset);
+
+static ssize_t u2_timeout_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct usb_device *hdev = interface_to_usbdev(intf);
+	struct lvs_rh *lvs = usb_get_intfdata(intf);
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &val);
+	if (ret < 0) {
+		dev_err(dev, "couldn't parse string %d\n", ret);
+		return ret;
+	}
+
+	if (val > 127)
+		return -EINVAL;
+
+	ret = lvs_rh_set_port_feature(hdev, lvs->portnum | (val << 8),
+			USB_PORT_FEAT_U2_TIMEOUT);
+	if (ret < 0) {
+		dev_err(dev, "Error %d while setting U2 timeout %ld\n", ret, val);
+		return ret;
+	}
+
+	return count;
+}
+static DEVICE_ATTR_WO(u2_timeout);
+
+static ssize_t u1_timeout_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct usb_device *hdev = interface_to_usbdev(intf);
+	struct lvs_rh *lvs = usb_get_intfdata(intf);
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul(buf, 10, &val);
+	if (ret < 0) {
+		dev_err(dev, "couldn't parse string %d\n", ret);
+		return ret;
+	}
+
+	if (val > 127)
+		return -EINVAL;
+
+	ret = lvs_rh_set_port_feature(hdev, lvs->portnum | (val << 8),
+			USB_PORT_FEAT_U1_TIMEOUT);
+	if (ret < 0) {
+		dev_err(dev, "Error %d while setting U1 timeout %ld\n", ret, val);
+		return ret;
+	}
+
+	return count;
+}
+static DEVICE_ATTR_WO(u1_timeout);
+
+static ssize_t get_dev_desc_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct usb_device *udev;
+	struct usb_device_descriptor *descriptor;
+	int ret;
+
+	descriptor = kmalloc_obj(*descriptor);
+	if (!descriptor)
+		return -ENOMEM;
+
+	udev = create_lvs_device(intf);
+	if (!udev) {
+		dev_err(dev, "failed to create lvs device\n");
+		ret = -ENOMEM;
+		goto free_desc;
+	}
+
+	ret = usb_control_msg(udev, (PIPE_CONTROL << 30) | USB_DIR_IN,
+			USB_REQ_GET_DESCRIPTOR, USB_DIR_IN, USB_DT_DEVICE << 8,
+			0, descriptor, sizeof(*descriptor),
+			USB_CTRL_GET_TIMEOUT);
+	if (ret < 0)
+		dev_err(dev, "can't read device descriptor %d\n", ret);
+
+	destroy_lvs_device(udev);
+
+free_desc:
+	kfree(descriptor);
+
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+static DEVICE_ATTR_WO(get_dev_desc);
+
+static ssize_t enable_compliance_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct usb_interface *intf = to_usb_interface(dev);
+	struct usb_device *hdev = interface_to_usbdev(intf);
+	struct lvs_rh *lvs = usb_get_intfdata(intf);
+	int ret;
+
+	ret = lvs_rh_set_port_feature(hdev,
+			lvs->portnum | USB_SS_PORT_LS_COMP_MOD << 3,
+			USB_PORT_FEAT_LINK_STATE);
+	if (ret < 0) {
+		dev_err(dev, "can't enable compliance mode %d\n", ret);
+		return ret;
+	}
+
+	return count;
+}
+static DEVICE_ATTR_WO(enable_compliance);
+
+static struct attribute *lvs_attrs[] = {
+	&dev_attr_get_dev_desc.attr,
+	&dev_attr_u1_timeout.attr,
+	&dev_attr_u2_timeout.attr,
+	&dev_attr_hot_reset.attr,
+	&dev_attr_warm_reset.attr,
+	&dev_attr_u3_entry.attr,
+	&dev_attr_u3_exit.attr,
+	&dev_attr_enable_compliance.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(lvs);
+
+static void lvs_rh_work(struct work_struct *work)
+{
+	struct lvs_rh *lvs = container_of(work, struct lvs_rh, rh_work);
+	struct usb_interface *intf = lvs->intf;
+	struct usb_device *hdev = interface_to_usbdev(intf);
+	struct usb_hcd *hcd = bus_to_hcd(hdev->bus);
+	struct usb_hub_descriptor *descriptor = &lvs->descriptor;
+	struct usb_port_status *port_status = &lvs->port_status;
+	int i, ret = 0;
+	u16 portchange;
+
+	/* Examine each root port */
+	for (i = 1; i <= descriptor->bNbrPorts; i++) {
+		ret = usb_control_msg(hdev, usb_rcvctrlpipe(hdev, 0),
+			USB_REQ_GET_STATUS, USB_DIR_IN | USB_RT_PORT, 0, i,
+			port_status, sizeof(*port_status), 1000);
+		if (ret < 4)
+			continue;
+
+		portchange = le16_to_cpu(port_status->wPortChange);
+
+		if (portchange & USB_PORT_STAT_C_LINK_STATE)
+			lvs_rh_clear_port_feature(hdev, i,
+					USB_PORT_FEAT_C_PORT_LINK_STATE);
+		if (portchange & USB_PORT_STAT_C_ENABLE)
+			lvs_rh_clear_port_feature(hdev, i,
+					USB_PORT_FEAT_C_ENABLE);
+		if (portchange & USB_PORT_STAT_C_RESET)
+			lvs_rh_clear_port_feature(hdev, i,
+					USB_PORT_FEAT_C_RESET);
+		if (portchange & USB_PORT_STAT_C_BH_RESET)
+			lvs_rh_clear_port_feature(hdev, i,
+					USB_PORT_FEAT_C_BH_PORT_RESET);
+		if (portchange & USB_PORT_STAT_C_CONNECTION) {
+			lvs_rh_clear_port_feature(hdev, i,
+					USB_PORT_FEAT_C_CONNECTION);
+
+			if (le16_to_cpu(port_status->wPortStatus) &
+					USB_PORT_STAT_CONNECTION) {
+				lvs->present = true;
+				lvs->portnum = i;
+				if (hcd->usb_phy)
+					usb_phy_notify_connect(hcd->usb_phy,
+							USB_SPEED_SUPER);
+			} else {
+				lvs->present = false;
+				if (hcd->usb_phy)
+					usb_phy_notify_disconnect(hcd->usb_phy,
+							USB_SPEED_SUPER);
+			}
+			break;
+		}
+	}
+
+	ret = usb_submit_urb(lvs->urb, GFP_KERNEL);
+	if (ret != 0 && ret != -ENODEV && ret != -EPERM)
+		dev_err(&intf->dev, "urb resubmit error %d\n", ret);
+}
+
+static void lvs_rh_irq(struct urb *urb)
+{
+	struct lvs_rh *lvs = urb->context;
+
+	schedule_work(&lvs->rh_work);
+}
+
+static int lvs_rh_probe(struct usb_interface *intf,
+		const struct usb_device_id *id)
+{
+	struct usb_device *hdev;
+	struct usb_host_interface *desc;
+	struct usb_endpoint_descriptor *endpoint;
+	struct lvs_rh *lvs;
+	unsigned int pipe;
+	int ret, maxp;
+
+	hdev = interface_to_usbdev(intf);
+	desc = intf->cur_altsetting;
+
+	ret = usb_find_int_in_endpoint(desc, &endpoint);
+	if (ret)
+		return ret;
+
+	/* valid only for SS root hub */
+	if (hdev->descriptor.bDeviceProtocol != USB_HUB_PR_SS || hdev->parent) {
+		dev_err(&intf->dev, "Bind LVS driver with SS root Hub only\n");
+		return -EINVAL;
+	}
+
+	lvs = devm_kzalloc(&intf->dev, sizeof(*lvs), GFP_KERNEL);
+	if (!lvs)
+		return -ENOMEM;
+
+	lvs->intf = intf;
+	usb_set_intfdata(intf, lvs);
+
+	/* how many number of ports this root hub has */
+	ret = usb_control_msg(hdev, usb_rcvctrlpipe(hdev, 0),
+			USB_REQ_GET_DESCRIPTOR, USB_DIR_IN | USB_RT_HUB,
+			USB_DT_SS_HUB << 8, 0, &lvs->descriptor,
+			USB_DT_SS_HUB_SIZE, USB_CTRL_GET_TIMEOUT);
+	if (ret < (USB_DT_HUB_NONVAR_SIZE + 2)) {
+		dev_err(&hdev->dev, "wrong root hub descriptor read %d\n", ret);
+		return ret < 0 ? ret : -EINVAL;
+	}
+
+	/* submit urb to poll interrupt endpoint */
+	lvs->urb = usb_alloc_urb(0, GFP_KERNEL);
+	if (!lvs->urb)
+		return -ENOMEM;
+
+	INIT_WORK(&lvs->rh_work, lvs_rh_work);
+
+	pipe = usb_rcvintpipe(hdev, endpoint->bEndpointAddress);
+	maxp = usb_maxpacket(hdev, pipe);
+	usb_fill_int_urb(lvs->urb, hdev, pipe, &lvs->buffer[0], maxp,
+			lvs_rh_irq, lvs, endpoint->bInterval);
+
+	ret = usb_submit_urb(lvs->urb, GFP_KERNEL);
+	if (ret < 0) {
+		dev_err(&intf->dev, "couldn't submit lvs urb %d\n", ret);
+		goto free_urb;
+	}
+
+	return ret;
+
+free_urb:
+	usb_free_urb(lvs->urb);
+	return ret;
+}
+
+static void lvs_rh_disconnect(struct usb_interface *intf)
+{
+	struct lvs_rh *lvs = usb_get_intfdata(intf);
+
+	usb_poison_urb(lvs->urb); /* used in scheduled work */
+	flush_work(&lvs->rh_work);
+	usb_free_urb(lvs->urb);
+}
+
+static struct usb_driver lvs_driver = {
+	.name =		"lvs",
+	.probe =	lvs_rh_probe,
+	.disconnect =	lvs_rh_disconnect,
+	.dev_groups =	lvs_groups,
+};
+
+module_usb_driver(lvs_driver);
+
+MODULE_DESCRIPTION("Link Layer Validation System Driver");
+MODULE_LICENSE("GPL");