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, 98 insertions, 0 deletions

diff --git a/drivers/hid/hid-glorious.c b/drivers/hid/hid-glorious.c
new file mode 100644
index 000000000..5bbd81248
--- /dev/null
+++ b/drivers/hid/hid-glorious.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  USB HID driver for Glorious PC Gaming Race
+ *  Glorious Model O, O- and D mice.
+ *
+ *  Copyright (c) 2020 Samuel Čavoj <sammko@sammserver.com>
+ */
+
+/*
+ */
+
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+MODULE_AUTHOR("Samuel Čavoj <sammko@sammserver.com>");
+MODULE_DESCRIPTION("HID driver for Glorious PC Gaming Race mice");
+
+/*
+ * Glorious Model O and O- specify the const flag in the consumer input
+ * report descriptor, which leads to inputs being ignored. Fix this
+ * by patching the descriptor.
+ *
+ * Glorious Model I incorrectly specifes the Usage Minimum for its
+ * keyboard HID report, causing keycodes to be misinterpreted.
+ * Fix this by setting Usage Minimum to 0 in that report.
+ */
+static const __u8 *glorious_report_fixup(struct hid_device *hdev, __u8 *rdesc,
+		unsigned int *rsize)
+{
+	if (*rsize == 213 &&
+		rdesc[84] == 129 && rdesc[112] == 129 && rdesc[140] == 129 &&
+		rdesc[85] == 3   && rdesc[113] == 3   && rdesc[141] == 3) {
+		hid_info(hdev, "patching Glorious Model O consumer control report descriptor\n");
+		rdesc[85] = rdesc[113] = rdesc[141] = \
+			HID_MAIN_ITEM_VARIABLE | HID_MAIN_ITEM_RELATIVE;
+	}
+	if (*rsize == 156 && rdesc[41] == 1) {
+		hid_info(hdev, "patching Glorious Model I keyboard report descriptor\n");
+		rdesc[41] = 0;
+	}
+	return rdesc;
+}
+
+static void glorious_update_name(struct hid_device *hdev)
+{
+	const char *model = "Device";
+
+	switch (hdev->product) {
+	case USB_DEVICE_ID_GLORIOUS_MODEL_O:
+		model = "Model O"; break;
+	case USB_DEVICE_ID_GLORIOUS_MODEL_D:
+		model = "Model D"; break;
+	case USB_DEVICE_ID_GLORIOUS_MODEL_I:
+		model = "Model I"; break;
+	}
+
+	snprintf(hdev->name, sizeof(hdev->name), "%s %s", "Glorious", model);
+}
+
+static int glorious_probe(struct hid_device *hdev,
+		const struct hid_device_id *id)
+{
+	int ret;
+
+	hdev->quirks |= HID_QUIRK_INPUT_PER_APP;
+
+	ret = hid_parse(hdev);
+	if (ret)
+		return ret;
+
+	glorious_update_name(hdev);
+
+	return hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+}
+
+static const struct hid_device_id glorious_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_SINOWEALTH,
+		USB_DEVICE_ID_GLORIOUS_MODEL_O) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_SINOWEALTH,
+		USB_DEVICE_ID_GLORIOUS_MODEL_D) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_LAVIEW,
+		USB_DEVICE_ID_GLORIOUS_MODEL_I) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, glorious_devices);
+
+static struct hid_driver glorious_driver = {
+	.name = "glorious",
+	.id_table = glorious_devices,
+	.probe = glorious_probe,
+	.report_fixup = glorious_report_fixup
+};
+
+module_hid_driver(glorious_driver);
+
+MODULE_LICENSE("GPL");