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, 206 insertions, 0 deletions

diff --git a/drivers/input/misc/yealink.h b/drivers/input/misc/yealink.h
new file mode 100644
index 000000000..69f700431
--- /dev/null
+++ b/drivers/input/misc/yealink.h
@@ -0,0 +1,206 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * drivers/usb/input/yealink.h
+ *
+ * Copyright (c) 2005 Henk Vergonet <Henk.Vergonet@gmail.com>
+ */
+#ifndef INPUT_YEALINK_H
+#define INPUT_YEALINK_H
+
+/* Using the control channel on interface 3 various aspects of the phone
+ * can be controlled like LCD, LED, dialtone and the ringtone.
+ */
+
+struct yld_ctl_packet {
+	u8	cmd;		/* command code, see below */
+	u8	size;		/* 1-11, size of used data bytes. */
+	__be16	offset;		/* internal packet offset */
+	u8	data[11];
+	s8	sum;		/* negative sum of 15 preceding bytes */
+} __attribute__ ((packed));
+
+#define USB_PKT_LEN	sizeof(struct yld_ctl_packet)
+
+/* The following yld_ctl_packet's are available: */
+
+/* Init registers
+ *
+ * cmd		0x8e
+ * size		10
+ * offset	0
+ * data		0,0,0,0....
+ */
+#define CMD_INIT		0x8e
+
+/* Request key scan
+ *
+ * cmd		0x80
+ * size		1
+ * offset	0
+ * data[0]	on return returns the key number, if it changes there's a new
+ * 		key pressed.
+ */
+#define CMD_KEYPRESS		0x80
+
+/* Request scancode
+ *
+ * cmd		0x81
+ * size		1
+ * offset	key number [0-1f]
+ * data[0]	on return returns the scancode
+ */
+#define CMD_SCANCODE		0x81
+
+/* Set LCD
+ *
+ * cmd		0x04
+ * size		1-11
+ * offset	0-23
+ * data		segment bits
+ */
+#define CMD_LCD			0x04
+
+/* Set led
+ *
+ * cmd		0x05
+ * size		1
+ * offset	0
+ * data[0]	0 OFF / 1 ON
+ */
+#define CMD_LED			0x05
+
+/* Set ringtone volume
+ *
+ * cmd		0x11
+ * size		1
+ * offset	0
+ * data[0]	0-0xff  volume
+ */
+#define CMD_RING_VOLUME		0x11
+
+/* Set ringtone notes
+ *
+ * cmd		0x02
+ * size		1-11
+ * offset	0->
+ * data		binary representation LE16(-freq), LE16(duration) ....
+ */
+#define CMD_RING_NOTE		0x02
+
+/* Sound ringtone via the speaker on the back
+ *
+ * cmd		0x03
+ * size		1
+ * offset	0
+ * data[0]	0 OFF / 0x24 ON
+ */
+#define CMD_RINGTONE		0x03
+
+/* Sound dial tone via the ear speaker
+ *
+ * cmd		0x09
+ * size		1
+ * offset	0
+ * data[0]	0 OFF / 1 ON
+ */
+#define CMD_DIALTONE		0x09
+
+#endif /* INPUT_YEALINK_H */
+
+
+#if defined(_SEG) && defined(_PIC)
+/* This table maps the LCD segments onto individual bit positions in the
+ * yld_status struct.
+ */
+
+/* LCD, each segment must be driven separately.
+ *
+ * Layout:
+ *
+ *   |[]   [][]   [][]   [][]   in   |[][]
+ *   |[] M [][] D [][] : [][]   out  |[][]
+ *                             store
+ *
+ *    NEW REP         SU MO TU WE TH FR SA
+ *
+ *    [] [] [] [] [] [] [] [] [] [] [] []
+ *    [] [] [] [] [] [] [] [] [] [] [] []
+ */
+
+/* Line 1
+ *	Format		: 18.e8.M8.88...188
+ *	Icon names	: M D : IN OUT STORE
+ */
+#define LCD_LINE1_OFFSET	0
+#define LCD_LINE1_SIZE		17
+
+/* Note: first g then f =>			       !      !      */
+/* _SEG(    type    a      b      c      d      e      g      f   )  */
+	_SEG('1',  0,0 , 22,2 , 22,2 ,  0,0 ,  0,0 ,  0,0 ,  0,0	),
+	_SEG('8', 20,1 , 20,2 , 20,4 , 20,8 , 21,4 , 21,2 , 21,1	),
+	_PIC('.', 22,1 , "M"						),
+	_SEG('e', 18,1 , 18,2 , 18,4 , 18,1 , 19,2 , 18,1 , 19,1	),
+	_SEG('8', 16,1 , 16,2 , 16,4 , 16,8 , 17,4 , 17,2 , 17,1	),
+	_PIC('.', 15,8 , "D"						),
+	_SEG('M', 14,1 , 14,2 , 14,4 , 14,1 , 15,4 , 15,2 , 15,1	),
+	_SEG('8', 12,1 , 12,2 , 12,4 , 12,8 , 13,4 , 13,2 , 13,1	),
+	_PIC('.', 11,8 , ":"						),
+	_SEG('8', 10,1 , 10,2 , 10,4 , 10,8 , 11,4 , 11,2 , 11,1	),
+	_SEG('8',  8,1 ,  8,2 ,  8,4 ,  8,8 ,  9,4 ,  9,2 ,  9,1	),
+	_PIC('.',  7,1 , "IN"						),
+	_PIC('.',  7,2 , "OUT"						),
+	_PIC('.',  7,4 , "STORE"					),
+	_SEG('1',  0,0 ,  5,1 ,  5,1 ,  0,0 ,  0,0 ,  0,0 ,  0,0	),
+	_SEG('8',  4,1 ,  4,2 ,  4,4 ,  4,8 ,  5,8 ,  5,4 ,  5,2	),
+	_SEG('8',  2,1 ,  2,2 ,  2,4 ,  2,8 ,  3,4 ,  3,2 ,  3,1	),
+
+/* Line 2
+ *	Format		: .........
+ *	Pict. name	: NEW REP SU MO TU WE TH FR SA
+ */
+#define LCD_LINE2_OFFSET	LCD_LINE1_OFFSET + LCD_LINE1_SIZE
+#define LCD_LINE2_SIZE		9
+
+	_PIC('.', 23,2 , "NEW"	),
+	_PIC('.', 23,4 , "REP"	),
+	_PIC('.',  1,8 , "SU"	),
+	_PIC('.',  1,4 , "MO"	),
+	_PIC('.',  1,2 , "TU"	),
+	_PIC('.',  1,1 , "WE"	),
+	_PIC('.',  0,1 , "TH"	),
+	_PIC('.',  0,2 , "FR"	),
+	_PIC('.',  0,4 , "SA"	),
+
+/* Line 3
+ *	Format		: 888888888888
+ */
+#define LCD_LINE3_OFFSET	LCD_LINE2_OFFSET + LCD_LINE2_SIZE
+#define LCD_LINE3_SIZE		12
+
+	_SEG('8', 22,16, 22,32, 22,64, 22,128, 23,128, 23,64, 23,32  ),
+	_SEG('8', 20,16, 20,32, 20,64, 20,128, 21,128, 21,64, 21,32  ),
+	_SEG('8', 18,16, 18,32, 18,64, 18,128, 19,128, 19,64, 19,32  ),
+	_SEG('8', 16,16, 16,32, 16,64, 16,128, 17,128, 17,64, 17,32  ),
+	_SEG('8', 14,16, 14,32, 14,64, 14,128, 15,128, 15,64, 15,32  ),
+	_SEG('8', 12,16, 12,32, 12,64, 12,128, 13,128, 13,64, 13,32  ),
+	_SEG('8', 10,16, 10,32, 10,64, 10,128, 11,128, 11,64, 11,32  ),
+	_SEG('8',  8,16,  8,32,  8,64,  8,128,  9,128,  9,64,  9,32  ),
+	_SEG('8',  6,16,  6,32,  6,64,  6,128,  7,128,  7,64,  7,32  ),
+	_SEG('8',  4,16,  4,32,  4,64,  4,128,  5,128,  5,64,  5,32  ),
+	_SEG('8',  2,16,  2,32,  2,64,  2,128,  3,128,  3,64,  3,32  ),
+	_SEG('8',  0,16,  0,32,  0,64,  0,128,  1,128,  1,64,  1,32  ),
+
+/* Line 4
+ *
+ * The LED, DIALTONE and RINGTONE are implemented as icons and use the same
+ * sysfs interface.
+ */
+#define LCD_LINE4_OFFSET	LCD_LINE3_OFFSET + LCD_LINE3_SIZE
+
+	_PIC('.', offsetof(struct yld_status, led)	, 0x01, "LED" ),
+	_PIC('.', offsetof(struct yld_status, dialtone) , 0x01, "DIALTONE" ),
+	_PIC('.', offsetof(struct yld_status, ringtone) , 0x24, "RINGTONE" ),
+
+#undef _SEG
+#undef _PIC
+#endif /* _SEG && _PIC */