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, 367 insertions, 0 deletions

diff --git a/net/bluetooth/mgmt_config.c b/net/bluetooth/mgmt_config.c
new file mode 100644
index 000000000..fdcc752c6
--- /dev/null
+++ b/net/bluetooth/mgmt_config.c
@@ -0,0 +1,367 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * Copyright (C) 2020 Google Corporation
+ */
+
+#include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci_core.h>
+#include <net/bluetooth/mgmt.h>
+
+#include "mgmt_util.h"
+#include "mgmt_config.h"
+
+#define HDEV_PARAM_U32(_param_name_) \
+	struct {\
+		struct mgmt_tlv_hdr entry; \
+		__le32 value; \
+	} __packed _param_name_
+
+#define HDEV_PARAM_U16(_param_name_) \
+	struct {\
+		struct mgmt_tlv_hdr entry; \
+		__le16 value; \
+	} __packed _param_name_
+
+#define HDEV_PARAM_U8(_param_name_) \
+	struct {\
+		struct mgmt_tlv_hdr entry; \
+		__u8 value; \
+	} __packed _param_name_
+
+#define TLV_SET_U16(_param_code_, _param_name_) \
+	{ \
+		{ cpu_to_le16(_param_code_), sizeof(__u16) }, \
+		cpu_to_le16(hdev->_param_name_) \
+	}
+
+#define TLV_SET_U32(_param_code_, _param_name_) \
+	{ \
+		{ cpu_to_le16(_param_code_), sizeof(__u32) }, \
+		cpu_to_le32(hdev->_param_name_) \
+	}
+
+#define TLV_SET_U8(_param_code_, _param_name_) \
+	{ \
+		{ cpu_to_le16(_param_code_), sizeof(__u8) }, \
+		hdev->_param_name_ \
+	}
+
+#define TLV_SET_U16_JIFFIES_TO_MSECS(_param_code_, _param_name_) \
+	{ \
+		{ cpu_to_le16(_param_code_), sizeof(__u16) }, \
+		cpu_to_le16(jiffies_to_msecs(hdev->_param_name_)) \
+	}
+
+int read_def_system_config(struct sock *sk, struct hci_dev *hdev, void *data,
+			   u16 data_len)
+{
+	int ret;
+	struct mgmt_rp_read_def_system_config {
+		/* Please see mgmt-api.txt for documentation of these values */
+		HDEV_PARAM_U16(def_page_scan_type);
+		HDEV_PARAM_U16(def_page_scan_int);
+		HDEV_PARAM_U16(def_page_scan_window);
+		HDEV_PARAM_U16(def_inq_scan_type);
+		HDEV_PARAM_U16(def_inq_scan_int);
+		HDEV_PARAM_U16(def_inq_scan_window);
+		HDEV_PARAM_U16(def_br_lsto);
+		HDEV_PARAM_U16(def_page_timeout);
+		HDEV_PARAM_U16(sniff_min_interval);
+		HDEV_PARAM_U16(sniff_max_interval);
+		HDEV_PARAM_U16(le_adv_min_interval);
+		HDEV_PARAM_U16(le_adv_max_interval);
+		HDEV_PARAM_U16(def_multi_adv_rotation_duration);
+		HDEV_PARAM_U16(le_scan_interval);
+		HDEV_PARAM_U16(le_scan_window);
+		HDEV_PARAM_U16(le_scan_int_suspend);
+		HDEV_PARAM_U16(le_scan_window_suspend);
+		HDEV_PARAM_U16(le_scan_int_discovery);
+		HDEV_PARAM_U16(le_scan_window_discovery);
+		HDEV_PARAM_U16(le_scan_int_adv_monitor);
+		HDEV_PARAM_U16(le_scan_window_adv_monitor);
+		HDEV_PARAM_U16(le_scan_int_connect);
+		HDEV_PARAM_U16(le_scan_window_connect);
+		HDEV_PARAM_U16(le_conn_min_interval);
+		HDEV_PARAM_U16(le_conn_max_interval);
+		HDEV_PARAM_U16(le_conn_latency);
+		HDEV_PARAM_U16(le_supv_timeout);
+		HDEV_PARAM_U16(def_le_autoconnect_timeout);
+		HDEV_PARAM_U16(advmon_allowlist_duration);
+		HDEV_PARAM_U16(advmon_no_filter_duration);
+		HDEV_PARAM_U8(enable_advmon_interleave_scan);
+		HDEV_PARAM_U32(idle_timeout);
+	} __packed rp = {
+		TLV_SET_U16(0x0000, def_page_scan_type),
+		TLV_SET_U16(0x0001, def_page_scan_int),
+		TLV_SET_U16(0x0002, def_page_scan_window),
+		TLV_SET_U16(0x0003, def_inq_scan_type),
+		TLV_SET_U16(0x0004, def_inq_scan_int),
+		TLV_SET_U16(0x0005, def_inq_scan_window),
+		TLV_SET_U16(0x0006, def_br_lsto),
+		TLV_SET_U16(0x0007, def_page_timeout),
+		TLV_SET_U16(0x0008, sniff_min_interval),
+		TLV_SET_U16(0x0009, sniff_max_interval),
+		TLV_SET_U16(0x000a, le_adv_min_interval),
+		TLV_SET_U16(0x000b, le_adv_max_interval),
+		TLV_SET_U16(0x000c, def_multi_adv_rotation_duration),
+		TLV_SET_U16(0x000d, le_scan_interval),
+		TLV_SET_U16(0x000e, le_scan_window),
+		TLV_SET_U16(0x000f, le_scan_int_suspend),
+		TLV_SET_U16(0x0010, le_scan_window_suspend),
+		TLV_SET_U16(0x0011, le_scan_int_discovery),
+		TLV_SET_U16(0x0012, le_scan_window_discovery),
+		TLV_SET_U16(0x0013, le_scan_int_adv_monitor),
+		TLV_SET_U16(0x0014, le_scan_window_adv_monitor),
+		TLV_SET_U16(0x0015, le_scan_int_connect),
+		TLV_SET_U16(0x0016, le_scan_window_connect),
+		TLV_SET_U16(0x0017, le_conn_min_interval),
+		TLV_SET_U16(0x0018, le_conn_max_interval),
+		TLV_SET_U16(0x0019, le_conn_latency),
+		TLV_SET_U16(0x001a, le_supv_timeout),
+		TLV_SET_U16_JIFFIES_TO_MSECS(0x001b,
+					     def_le_autoconnect_timeout),
+		TLV_SET_U16(0x001d, advmon_allowlist_duration),
+		TLV_SET_U16(0x001e, advmon_no_filter_duration),
+		TLV_SET_U8(0x001f, enable_advmon_interleave_scan),
+		TLV_SET_U32(0x0020, idle_timeout),
+	};
+
+	bt_dev_dbg(hdev, "sock %p", sk);
+
+	ret = mgmt_cmd_complete(sk, hdev->id,
+				MGMT_OP_READ_DEF_SYSTEM_CONFIG,
+				0, &rp, sizeof(rp));
+	return ret;
+}
+
+#define TO_TLV(x)		((struct mgmt_tlv *)(x))
+#define TLV_GET_LE32(tlv)	le32_to_cpu(*((__le32 *)(TO_TLV(tlv)->value)))
+#define TLV_GET_LE16(tlv)	le16_to_cpu(*((__le16 *)(TO_TLV(tlv)->value)))
+#define TLV_GET_U8(tlv)		(*((__u8 *)(TO_TLV(tlv)->value)))
+
+int set_def_system_config(struct sock *sk, struct hci_dev *hdev, void *data,
+			  u16 data_len)
+{
+	u16 buffer_left = data_len;
+	u8 *buffer = data;
+
+	if (buffer_left < sizeof(struct mgmt_tlv)) {
+		return mgmt_cmd_status(sk, hdev->id,
+				       MGMT_OP_SET_DEF_SYSTEM_CONFIG,
+				       MGMT_STATUS_INVALID_PARAMS);
+	}
+
+	/* First pass to validate the tlv */
+	while (buffer_left >= sizeof(struct mgmt_tlv)) {
+		const u8 len = TO_TLV(buffer)->length;
+		size_t exp_type_len;
+		const u16 exp_len = sizeof(struct mgmt_tlv) +
+				    len;
+		const u16 type = le16_to_cpu(TO_TLV(buffer)->type);
+
+		if (buffer_left < exp_len) {
+			bt_dev_warn(hdev, "invalid len left %u, exp >= %u",
+				    buffer_left, exp_len);
+
+			return mgmt_cmd_status(sk, hdev->id,
+					MGMT_OP_SET_DEF_SYSTEM_CONFIG,
+					MGMT_STATUS_INVALID_PARAMS);
+		}
+
+		/* Please see mgmt-api.txt for documentation of these values */
+		switch (type) {
+		case 0x0000:
+		case 0x0001:
+		case 0x0002:
+		case 0x0003:
+		case 0x0004:
+		case 0x0005:
+		case 0x0006:
+		case 0x0007:
+		case 0x0008:
+		case 0x0009:
+		case 0x000a:
+		case 0x000b:
+		case 0x000c:
+		case 0x000d:
+		case 0x000e:
+		case 0x000f:
+		case 0x0010:
+		case 0x0011:
+		case 0x0012:
+		case 0x0013:
+		case 0x0014:
+		case 0x0015:
+		case 0x0016:
+		case 0x0017:
+		case 0x0018:
+		case 0x0019:
+		case 0x001a:
+		case 0x001b:
+		case 0x001d:
+		case 0x001e:
+			exp_type_len = sizeof(u16);
+			break;
+		case 0x001f:
+			exp_type_len = sizeof(u8);
+			break;
+		case 0x0020:
+			exp_type_len = sizeof(u32);
+			break;
+		default:
+			exp_type_len = 0;
+			bt_dev_warn(hdev, "unsupported parameter %u", type);
+			break;
+		}
+
+		if (exp_type_len && len != exp_type_len) {
+			bt_dev_warn(hdev, "invalid length %d, exp %zu for type %u",
+				    len, exp_type_len, type);
+
+			return mgmt_cmd_status(sk, hdev->id,
+				MGMT_OP_SET_DEF_SYSTEM_CONFIG,
+				MGMT_STATUS_INVALID_PARAMS);
+		}
+
+		buffer_left -= exp_len;
+		buffer += exp_len;
+	}
+
+	buffer_left = data_len;
+	buffer = data;
+	while (buffer_left >= sizeof(struct mgmt_tlv)) {
+		const u8 len = TO_TLV(buffer)->length;
+		const u16 exp_len = sizeof(struct mgmt_tlv) +
+				    len;
+		const u16 type = le16_to_cpu(TO_TLV(buffer)->type);
+
+		switch (type) {
+		case 0x0000:
+			hdev->def_page_scan_type = TLV_GET_LE16(buffer);
+			break;
+		case 0x0001:
+			hdev->def_page_scan_int = TLV_GET_LE16(buffer);
+			break;
+		case 0x0002:
+			hdev->def_page_scan_window = TLV_GET_LE16(buffer);
+			break;
+		case 0x0003:
+			hdev->def_inq_scan_type = TLV_GET_LE16(buffer);
+			break;
+		case 0x0004:
+			hdev->def_inq_scan_int = TLV_GET_LE16(buffer);
+			break;
+		case 0x0005:
+			hdev->def_inq_scan_window = TLV_GET_LE16(buffer);
+			break;
+		case 0x0006:
+			hdev->def_br_lsto = TLV_GET_LE16(buffer);
+			break;
+		case 0x0007:
+			hdev->def_page_timeout = TLV_GET_LE16(buffer);
+			break;
+		case 0x0008:
+			hdev->sniff_min_interval = TLV_GET_LE16(buffer);
+			break;
+		case 0x0009:
+			hdev->sniff_max_interval = TLV_GET_LE16(buffer);
+			break;
+		case 0x000a:
+			hdev->le_adv_min_interval = TLV_GET_LE16(buffer);
+			break;
+		case 0x000b:
+			hdev->le_adv_max_interval = TLV_GET_LE16(buffer);
+			break;
+		case 0x000c:
+			hdev->def_multi_adv_rotation_duration =
+							   TLV_GET_LE16(buffer);
+			break;
+		case 0x000d:
+			hdev->le_scan_interval = TLV_GET_LE16(buffer);
+			break;
+		case 0x000e:
+			hdev->le_scan_window = TLV_GET_LE16(buffer);
+			break;
+		case 0x000f:
+			hdev->le_scan_int_suspend = TLV_GET_LE16(buffer);
+			break;
+		case 0x0010:
+			hdev->le_scan_window_suspend = TLV_GET_LE16(buffer);
+			break;
+		case 0x0011:
+			hdev->le_scan_int_discovery = TLV_GET_LE16(buffer);
+			break;
+		case 0x00012:
+			hdev->le_scan_window_discovery = TLV_GET_LE16(buffer);
+			break;
+		case 0x00013:
+			hdev->le_scan_int_adv_monitor = TLV_GET_LE16(buffer);
+			break;
+		case 0x00014:
+			hdev->le_scan_window_adv_monitor = TLV_GET_LE16(buffer);
+			break;
+		case 0x00015:
+			hdev->le_scan_int_connect = TLV_GET_LE16(buffer);
+			break;
+		case 0x00016:
+			hdev->le_scan_window_connect = TLV_GET_LE16(buffer);
+			break;
+		case 0x00017:
+			hdev->le_conn_min_interval = TLV_GET_LE16(buffer);
+			break;
+		case 0x00018:
+			hdev->le_conn_max_interval = TLV_GET_LE16(buffer);
+			break;
+		case 0x00019:
+			hdev->le_conn_latency = TLV_GET_LE16(buffer);
+			break;
+		case 0x0001a:
+			hdev->le_supv_timeout = TLV_GET_LE16(buffer);
+			break;
+		case 0x0001b:
+			hdev->def_le_autoconnect_timeout =
+					msecs_to_jiffies(TLV_GET_LE16(buffer));
+			break;
+		case 0x0001d:
+			hdev->advmon_allowlist_duration = TLV_GET_LE16(buffer);
+			break;
+		case 0x0001e:
+			hdev->advmon_no_filter_duration = TLV_GET_LE16(buffer);
+			break;
+		case 0x0001f:
+			hdev->enable_advmon_interleave_scan = TLV_GET_U8(buffer);
+			break;
+		case 0x00020:
+			hdev->idle_timeout = TLV_GET_LE32(buffer);
+			break;
+		default:
+			bt_dev_warn(hdev, "unsupported parameter %u", type);
+			break;
+		}
+
+		buffer_left -= exp_len;
+		buffer += exp_len;
+	}
+
+	return mgmt_cmd_complete(sk, hdev->id,
+				 MGMT_OP_SET_DEF_SYSTEM_CONFIG, 0, NULL, 0);
+}
+
+int read_def_runtime_config(struct sock *sk, struct hci_dev *hdev, void *data,
+			    u16 data_len)
+{
+	bt_dev_dbg(hdev, "sock %p", sk);
+
+	return mgmt_cmd_complete(sk, hdev->id,
+				 MGMT_OP_READ_DEF_RUNTIME_CONFIG, 0, NULL, 0);
+}
+
+int set_def_runtime_config(struct sock *sk, struct hci_dev *hdev, void *data,
+			   u16 data_len)
+{
+	bt_dev_dbg(hdev, "sock %p", sk);
+
+	return mgmt_cmd_status(sk, hdev->id, MGMT_OP_SET_DEF_SYSTEM_CONFIG,
+			       MGMT_STATUS_INVALID_PARAMS);
+}