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, 239 insertions, 0 deletions

diff --git a/drivers/hid/hid-icade.c b/drivers/hid/hid-icade.c
new file mode 100644
index 000000000..f3716cfac
--- /dev/null
+++ b/drivers/hid/hid-icade.c
@@ -0,0 +1,239 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  ION iCade input driver
+ *
+ *  Copyright (c) 2012 Bastien Nocera <hadess@hadess.net>
+ *  Copyright (c) 2012 Benjamin Tissoires <benjamin.tissoires@gmail.com>
+ */
+
+/*
+ */
+
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+/*
+ *   ↑      A C Y L
+ *  ← →
+ *   ↓      B X Z R
+ *
+ *
+ *  UP ON,OFF  = w,e
+ *  RT ON,OFF  = d,c
+ *  DN ON,OFF  = x,z
+ *  LT ON,OFF  = a,q
+ *  A  ON,OFF  = y,t
+ *  B  ON,OFF  = h,r
+ *  C  ON,OFF  = u,f
+ *  X  ON,OFF  = j,n
+ *  Y  ON,OFF  = i,m
+ *  Z  ON,OFF  = k,p
+ *  L  ON,OFF  = o,g
+ *  R  ON,OFF  = l,v
+ */
+
+/* The translation code uses HID usage instead of input layer
+ * keys. This code generates a lookup table that makes
+ * translation quick.
+ *
+ * #include <linux/input.h>
+ * #include <stdio.h>
+ * #include <assert.h>
+ *
+ * #define unk     KEY_UNKNOWN
+ *
+ * < copy of hid_keyboard[] from hid-input.c >
+ *
+ * struct icade_key_translation {
+ *     int         from;
+ *     const char *to;
+ *     int         press;
+ * };
+ *
+ * static const struct icade_key_translation icade_keys[] = {
+ *    { KEY_W,        "KEY_UP",         1 },
+ *    { KEY_E,        "KEY_UP",         0 },
+ *    { KEY_D,        "KEY_RIGHT",      1 },
+ *    { KEY_C,        "KEY_RIGHT",      0 },
+ *    { KEY_X,        "KEY_DOWN",       1 },
+ *    { KEY_Z,        "KEY_DOWN",       0 },
+ *    { KEY_A,        "KEY_LEFT",       1 },
+ *    { KEY_Q,        "KEY_LEFT",       0 },
+ *    { KEY_Y,        "BTN_A",          1 },
+ *    { KEY_T,        "BTN_A",          0 },
+ *    { KEY_H,        "BTN_B",          1 },
+ *    { KEY_R,        "BTN_B",          0 },
+ *    { KEY_U,        "BTN_C",          1 },
+ *    { KEY_F,        "BTN_C",          0 },
+ *    { KEY_J,        "BTN_X",          1 },
+ *    { KEY_N,        "BTN_X",          0 },
+ *    { KEY_I,        "BTN_Y",          1 },
+ *    { KEY_M,        "BTN_Y",          0 },
+ *    { KEY_K,        "BTN_Z",          1 },
+ *    { KEY_P,        "BTN_Z",          0 },
+ *    { KEY_O,        "BTN_THUMBL",     1 },
+ *    { KEY_G,        "BTN_THUMBL",     0 },
+ *    { KEY_L,        "BTN_THUMBR",     1 },
+ *    { KEY_V,        "BTN_THUMBR",     0 },
+ *
+ *    { }
+ * };
+ *
+ * static int
+ * usage_for_key (int key)
+ * {
+ *     int i;
+ *     for (i = 0; i < 256; i++) {
+ *     if (hid_keyboard[i] == key)
+ *         return i;
+ *     }
+ *     assert(0);
+ * }
+ *
+ * int main (int argc, char **argv)
+ * {
+ *     const struct icade_key_translation *trans;
+ *     int max_usage = 0;
+ *
+ *     for (trans = icade_keys; trans->from; trans++) {
+ *         int usage = usage_for_key (trans->from);
+ *         max_usage = usage > max_usage ? usage : max_usage;
+ *     }
+ *
+ *     printf ("#define ICADE_MAX_USAGE %d\n\n", max_usage);
+ *     printf ("struct icade_key {\n");
+ *     printf ("\tu16 to;\n");
+ *     printf ("\tu8 press:1;\n");
+ *     printf ("};\n\n");
+ *     printf ("static const struct icade_key "
+ *             "icade_usage_table[%d] = {\n", max_usage + 1);
+ *     for (trans = icade_keys; trans->from; trans++) {
+ *         printf ("\t[%d] = { %s, %d },\n",
+ *                 usage_for_key (trans->from), trans->to, trans->press);
+ *     }
+ *     printf ("};\n");
+ *
+ *     return 0;
+ * }
+ */
+
+#define ICADE_MAX_USAGE 29
+
+struct icade_key {
+	u16 to;
+	u8 press:1;
+};
+
+static const struct icade_key icade_usage_table[30] = {
+	[26] = { KEY_UP, 1 },
+	[8] = { KEY_UP, 0 },
+	[7] = { KEY_RIGHT, 1 },
+	[6] = { KEY_RIGHT, 0 },
+	[27] = { KEY_DOWN, 1 },
+	[29] = { KEY_DOWN, 0 },
+	[4] = { KEY_LEFT, 1 },
+	[20] = { KEY_LEFT, 0 },
+	[28] = { BTN_A, 1 },
+	[23] = { BTN_A, 0 },
+	[11] = { BTN_B, 1 },
+	[21] = { BTN_B, 0 },
+	[24] = { BTN_C, 1 },
+	[9] = { BTN_C, 0 },
+	[13] = { BTN_X, 1 },
+	[17] = { BTN_X, 0 },
+	[12] = { BTN_Y, 1 },
+	[16] = { BTN_Y, 0 },
+	[14] = { BTN_Z, 1 },
+	[19] = { BTN_Z, 0 },
+	[18] = { BTN_THUMBL, 1 },
+	[10] = { BTN_THUMBL, 0 },
+	[15] = { BTN_THUMBR, 1 },
+	[25] = { BTN_THUMBR, 0 },
+};
+
+static const struct icade_key *icade_find_translation(u16 from)
+{
+	if (from > ICADE_MAX_USAGE)
+		return NULL;
+	return &icade_usage_table[from];
+}
+
+static int icade_event(struct hid_device *hdev, struct hid_field *field,
+		struct hid_usage *usage, __s32 value)
+{
+	const struct icade_key *trans;
+
+	if (!(hdev->claimed & HID_CLAIMED_INPUT) || !field->hidinput ||
+			!usage->type)
+		return 0;
+
+	/* We ignore the fake key up, and act only on key down */
+	if (!value)
+		return 1;
+
+	trans = icade_find_translation(usage->hid & HID_USAGE);
+
+	if (!trans)
+		return 1;
+
+	input_event(field->hidinput->input, usage->type,
+			trans->to, trans->press);
+
+	return 1;
+}
+
+static int icade_input_mapping(struct hid_device *hdev, struct hid_input *hi,
+		struct hid_field *field, struct hid_usage *usage,
+		unsigned long **bit, int *max)
+{
+	const struct icade_key *trans;
+
+	if ((usage->hid & HID_USAGE_PAGE) == HID_UP_KEYBOARD) {
+		trans = icade_find_translation(usage->hid & HID_USAGE);
+
+		if (!trans)
+			return -1;
+
+		hid_map_usage(hi, usage, bit, max, EV_KEY, trans->to);
+		set_bit(trans->to, hi->input->keybit);
+
+		return 1;
+	}
+
+	/* ignore others */
+	return -1;
+
+}
+
+static int icade_input_mapped(struct hid_device *hdev, struct hid_input *hi,
+		struct hid_field *field, struct hid_usage *usage,
+		unsigned long **bit, int *max)
+{
+	if (usage->type == EV_KEY)
+		set_bit(usage->type, hi->input->evbit);
+
+	return -1;
+}
+
+static const struct hid_device_id icade_devices[] = {
+	{ HID_BLUETOOTH_DEVICE(USB_VENDOR_ID_ION, USB_DEVICE_ID_ICADE) },
+
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, icade_devices);
+
+static struct hid_driver icade_driver = {
+	.name = "icade",
+	.id_table = icade_devices,
+	.event = icade_event,
+	.input_mapped = icade_input_mapped,
+	.input_mapping = icade_input_mapping,
+};
+module_hid_driver(icade_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Bastien Nocera <hadess@hadess.net>");
+MODULE_DESCRIPTION("ION iCade input driver");