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, 564 insertions, 0 deletions

diff --git a/fs/smb/server/smb2misc.c b/fs/smb/server/smb2misc.c
new file mode 100644
index 000000000..532dea7be
--- /dev/null
+++ b/fs/smb/server/smb2misc.c
@@ -0,0 +1,564 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *   Copyright (C) 2016 Namjae Jeon <linkinjeon@kernel.org>
+ *   Copyright (C) 2018 Samsung Electronics Co., Ltd.
+ */
+
+#include "glob.h"
+#include "smb_common.h"
+#include "../common/smb2status.h"
+#include "mgmt/user_session.h"
+#include "connection.h"
+
+static int check_smb2_hdr(struct smb2_hdr *hdr)
+{
+	/*
+	 * Make sure that this really is an SMB, that it is a response.
+	 */
+	if (hdr->Flags & SMB2_FLAGS_SERVER_TO_REDIR)
+		return 1;
+	return 0;
+}
+
+/*
+ *  The following table defines the expected "StructureSize" of SMB2 requests
+ *  in order by SMB2 command.  This is similar to "wct" in SMB/CIFS requests.
+ *
+ *  Note that commands are defined in smb2pdu.h in le16 but the array below is
+ *  indexed by command in host byte order
+ */
+static const __le16 smb2_req_struct_sizes[NUMBER_OF_SMB2_COMMANDS] = {
+	/* SMB2_NEGOTIATE */ cpu_to_le16(36),
+	/* SMB2_SESSION_SETUP */ cpu_to_le16(25),
+	/* SMB2_LOGOFF */ cpu_to_le16(4),
+	/* SMB2_TREE_CONNECT */ cpu_to_le16(9),
+	/* SMB2_TREE_DISCONNECT */ cpu_to_le16(4),
+	/* SMB2_CREATE */ cpu_to_le16(57),
+	/* SMB2_CLOSE */ cpu_to_le16(24),
+	/* SMB2_FLUSH */ cpu_to_le16(24),
+	/* SMB2_READ */ cpu_to_le16(49),
+	/* SMB2_WRITE */ cpu_to_le16(49),
+	/* SMB2_LOCK */ cpu_to_le16(48),
+	/* SMB2_IOCTL */ cpu_to_le16(57),
+	/* SMB2_CANCEL */ cpu_to_le16(4),
+	/* SMB2_ECHO */ cpu_to_le16(4),
+	/* SMB2_QUERY_DIRECTORY */ cpu_to_le16(33),
+	/* SMB2_CHANGE_NOTIFY */ cpu_to_le16(32),
+	/* SMB2_QUERY_INFO */ cpu_to_le16(41),
+	/* SMB2_SET_INFO */ cpu_to_le16(33),
+	/* use 44 for lease break */
+	/* SMB2_OPLOCK_BREAK */ cpu_to_le16(36)
+};
+
+/*
+ * The size of the variable area depends on the offset and length fields
+ * located in different fields for various SMB2 requests. SMB2 requests
+ * with no variable length info, show an offset of zero for the offset field.
+ */
+static const bool has_smb2_data_area[NUMBER_OF_SMB2_COMMANDS] = {
+	/* SMB2_NEGOTIATE */ true,
+	/* SMB2_SESSION_SETUP */ true,
+	/* SMB2_LOGOFF */ false,
+	/* SMB2_TREE_CONNECT */	true,
+	/* SMB2_TREE_DISCONNECT */ false,
+	/* SMB2_CREATE */ true,
+	/* SMB2_CLOSE */ false,
+	/* SMB2_FLUSH */ false,
+	/* SMB2_READ */	true,
+	/* SMB2_WRITE */ true,
+	/* SMB2_LOCK */	true,
+	/* SMB2_IOCTL */ true,
+	/* SMB2_CANCEL */ false, /* BB CHECK this not listed in documentation */
+	/* SMB2_ECHO */ false,
+	/* SMB2_QUERY_DIRECTORY */ true,
+	/* SMB2_CHANGE_NOTIFY */ false,
+	/* SMB2_QUERY_INFO */ true,
+	/* SMB2_SET_INFO */ true,
+	/* SMB2_OPLOCK_BREAK */ false
+};
+
+/*
+ * Set length of the data area and the offset to arguments.
+ * if they are invalid, return error.
+ */
+static int smb2_get_data_area_len(unsigned int *off, unsigned int *len,
+				  struct smb2_hdr *hdr)
+{
+	int ret = 0;
+
+	*off = 0;
+	*len = 0;
+
+	/*
+	 * Following commands have data areas so we have to get the location
+	 * of the data buffer offset and data buffer length for the particular
+	 * command.
+	 */
+	switch (hdr->Command) {
+	case SMB2_SESSION_SETUP:
+		*off = le16_to_cpu(((struct smb2_sess_setup_req *)hdr)->SecurityBufferOffset);
+		*len = le16_to_cpu(((struct smb2_sess_setup_req *)hdr)->SecurityBufferLength);
+		break;
+	case SMB2_TREE_CONNECT:
+		*off = max_t(unsigned short int,
+			     le16_to_cpu(((struct smb2_tree_connect_req *)hdr)->PathOffset),
+			     offsetof(struct smb2_tree_connect_req, Buffer));
+		*len = le16_to_cpu(((struct smb2_tree_connect_req *)hdr)->PathLength);
+		break;
+	case SMB2_CREATE:
+	{
+		unsigned short int name_off =
+			max_t(unsigned short int,
+			      le16_to_cpu(((struct smb2_create_req *)hdr)->NameOffset),
+			      offsetof(struct smb2_create_req, Buffer));
+		unsigned short int name_len =
+			le16_to_cpu(((struct smb2_create_req *)hdr)->NameLength);
+
+		if (((struct smb2_create_req *)hdr)->CreateContextsLength) {
+			*off = le32_to_cpu(((struct smb2_create_req *)
+				hdr)->CreateContextsOffset);
+			*len = le32_to_cpu(((struct smb2_create_req *)
+				hdr)->CreateContextsLength);
+			if (!name_len)
+				break;
+
+			if (name_off + name_len < (u64)*off + *len)
+				break;
+		}
+
+		*off = name_off;
+		*len = name_len;
+		break;
+	}
+	case SMB2_QUERY_INFO:
+		*off = max_t(unsigned int,
+			     le16_to_cpu(((struct smb2_query_info_req *)hdr)->InputBufferOffset),
+			     offsetof(struct smb2_query_info_req, Buffer));
+		*len = le32_to_cpu(((struct smb2_query_info_req *)hdr)->InputBufferLength);
+		break;
+	case SMB2_SET_INFO:
+		*off = max_t(unsigned int,
+			     le16_to_cpu(((struct smb2_set_info_req *)hdr)->BufferOffset),
+			     offsetof(struct smb2_set_info_req, Buffer));
+		*len = le32_to_cpu(((struct smb2_set_info_req *)hdr)->BufferLength);
+		break;
+	case SMB2_READ:
+		*off = le16_to_cpu(((struct smb2_read_req *)hdr)->ReadChannelInfoOffset);
+		*len = le16_to_cpu(((struct smb2_read_req *)hdr)->ReadChannelInfoLength);
+		break;
+	case SMB2_WRITE:
+		if (((struct smb2_write_req *)hdr)->DataOffset ||
+		    ((struct smb2_write_req *)hdr)->Length) {
+			*off = max_t(unsigned short int,
+				     le16_to_cpu(((struct smb2_write_req *)hdr)->DataOffset),
+				     offsetof(struct smb2_write_req, Buffer));
+			*len = le32_to_cpu(((struct smb2_write_req *)hdr)->Length);
+			break;
+		}
+
+		*off = le16_to_cpu(((struct smb2_write_req *)hdr)->WriteChannelInfoOffset);
+		*len = le16_to_cpu(((struct smb2_write_req *)hdr)->WriteChannelInfoLength);
+		break;
+	case SMB2_QUERY_DIRECTORY:
+		*off = max_t(unsigned short int,
+			     le16_to_cpu(((struct smb2_query_directory_req *)hdr)->FileNameOffset),
+			     offsetof(struct smb2_query_directory_req, Buffer));
+		*len = le16_to_cpu(((struct smb2_query_directory_req *)hdr)->FileNameLength);
+		break;
+	case SMB2_LOCK:
+	{
+		unsigned short lock_count;
+
+		lock_count = le16_to_cpu(((struct smb2_lock_req *)hdr)->LockCount);
+		if (lock_count > 0) {
+			*off = offsetof(struct smb2_lock_req, locks);
+			*len = sizeof(struct smb2_lock_element) * lock_count;
+		}
+		break;
+	}
+	case SMB2_IOCTL:
+		*off = max_t(unsigned int,
+			     le32_to_cpu(((struct smb2_ioctl_req *)hdr)->InputOffset),
+			     offsetof(struct smb2_ioctl_req, Buffer));
+		*len = le32_to_cpu(((struct smb2_ioctl_req *)hdr)->InputCount);
+		break;
+	default:
+		ksmbd_debug(SMB, "no length check for command\n");
+		break;
+	}
+
+	if (*off > 4096) {
+		ksmbd_debug(SMB, "offset %d too large\n", *off);
+		ret = -EINVAL;
+	} else if ((u64)*off + *len > MAX_STREAM_PROT_LEN) {
+		ksmbd_debug(SMB, "Request is larger than maximum stream protocol length(%u): %llu\n",
+			    MAX_STREAM_PROT_LEN, (u64)*off + *len);
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+/*
+ * Calculate the size of the SMB message based on the fixed header
+ * portion, the number of word parameters and the data portion of the message.
+ */
+static int smb2_calc_size(void *buf, unsigned int *len)
+{
+	struct smb2_pdu *pdu = (struct smb2_pdu *)buf;
+	struct smb2_hdr *hdr = &pdu->hdr;
+	unsigned int offset; /* the offset from the beginning of SMB to data area */
+	unsigned int data_length; /* the length of the variable length data area */
+	int ret;
+
+	/* Structure Size has already been checked to make sure it is 64 */
+	*len = le16_to_cpu(hdr->StructureSize);
+
+	/*
+	 * StructureSize2, ie length of fixed parameter area has already
+	 * been checked to make sure it is the correct length.
+	 */
+	*len += le16_to_cpu(pdu->StructureSize2);
+	/*
+	 * StructureSize2 of smb2_lock pdu is set to 48, indicating
+	 * the size of smb2 lock request with single smb2_lock_element
+	 * regardless of number of locks. Subtract single
+	 * smb2_lock_element for correct buffer size check.
+	 */
+	if (hdr->Command == SMB2_LOCK)
+		*len -= sizeof(struct smb2_lock_element);
+
+	if (has_smb2_data_area[le16_to_cpu(hdr->Command)] == false)
+		goto calc_size_exit;
+
+	ret = smb2_get_data_area_len(&offset, &data_length, hdr);
+	if (ret)
+		return ret;
+	ksmbd_debug(SMB, "SMB2 data length %u offset %u\n", data_length,
+		    offset);
+
+	if (data_length > 0) {
+		/*
+		 * Check to make sure that data area begins after fixed area,
+		 * Note that last byte of the fixed area is part of data area
+		 * for some commands, typically those with odd StructureSize,
+		 * so we must add one to the calculation.
+		 */
+		if (offset + 1 < *len) {
+			ksmbd_debug(SMB,
+				    "data area offset %d overlaps SMB2 header %u\n",
+				    offset + 1, *len);
+			return -EINVAL;
+		}
+
+		*len = offset + data_length;
+	}
+
+calc_size_exit:
+	ksmbd_debug(SMB, "SMB2 len %u\n", *len);
+	return 0;
+}
+
+static inline int smb2_query_info_req_len(struct smb2_query_info_req *h)
+{
+	return le32_to_cpu(h->InputBufferLength);
+}
+
+static inline int smb2_query_info_resp_len(struct smb2_query_info_req *h)
+{
+	return le32_to_cpu(h->OutputBufferLength);
+}
+
+static inline int smb2_set_info_req_len(struct smb2_set_info_req *h)
+{
+	return le32_to_cpu(h->BufferLength);
+}
+
+static inline int smb2_read_req_len(struct smb2_read_req *h)
+{
+	return le32_to_cpu(h->Length);
+}
+
+static inline int smb2_write_req_len(struct smb2_write_req *h)
+{
+	return le32_to_cpu(h->Length);
+}
+
+static inline int smb2_query_dir_req_len(struct smb2_query_directory_req *h)
+{
+	return le32_to_cpu(h->OutputBufferLength);
+}
+
+static inline int smb2_ioctl_req_len(struct smb2_ioctl_req *h)
+{
+	return le32_to_cpu(h->InputCount) +
+		le32_to_cpu(h->OutputCount);
+}
+
+static inline int smb2_ioctl_resp_len(struct smb2_ioctl_req *h)
+{
+	return le32_to_cpu(h->MaxInputResponse) +
+		le32_to_cpu(h->MaxOutputResponse);
+}
+
+static int smb2_validate_credit_charge(struct ksmbd_work *work,
+				       struct smb2_hdr *hdr)
+{
+	struct ksmbd_conn *conn = work->conn;
+	unsigned int req_len = 0, expect_resp_len = 0, calc_credit_num, max_len;
+	unsigned short credit_charge = le16_to_cpu(hdr->CreditCharge);
+	void *__hdr = hdr;
+	int ret = 0;
+
+	switch (hdr->Command) {
+	case SMB2_QUERY_INFO:
+		req_len = smb2_query_info_req_len(__hdr);
+		expect_resp_len = smb2_query_info_resp_len(__hdr);
+		break;
+	case SMB2_SET_INFO:
+		req_len = smb2_set_info_req_len(__hdr);
+		break;
+	case SMB2_READ:
+		req_len = smb2_read_req_len(__hdr);
+		break;
+	case SMB2_WRITE:
+		req_len = smb2_write_req_len(__hdr);
+		break;
+	case SMB2_QUERY_DIRECTORY:
+		req_len = smb2_query_dir_req_len(__hdr);
+		break;
+	case SMB2_IOCTL:
+		req_len = smb2_ioctl_req_len(__hdr);
+		expect_resp_len = smb2_ioctl_resp_len(__hdr);
+		break;
+	case SMB2_CANCEL:
+		return 0;
+	default:
+		req_len = 1;
+		break;
+	}
+
+	credit_charge = max_t(unsigned short, credit_charge, 1);
+	max_len = max_t(unsigned int, req_len, expect_resp_len);
+	calc_credit_num = DIV_ROUND_UP(max_len, SMB2_MAX_BUFFER_SIZE);
+
+	if (credit_charge < calc_credit_num) {
+		ksmbd_debug(SMB, "Insufficient credit charge, given: %d, needed: %d\n",
+			    credit_charge, calc_credit_num);
+		return 1;
+	} else if (credit_charge > conn->vals->max_credits) {
+		ksmbd_debug(SMB, "Too large credit charge: %d\n", credit_charge);
+		return 1;
+	}
+
+	spin_lock(&conn->credits_lock);
+	if (credit_charge > conn->total_credits) {
+		ksmbd_debug(SMB, "Insufficient credits granted, given: %u, granted: %u\n",
+			    credit_charge, conn->total_credits);
+		ret = 1;
+	}
+
+	if ((u64)conn->outstanding_credits + credit_charge > conn->total_credits) {
+		ksmbd_debug(SMB, "Limits exceeding the maximum allowable outstanding requests, given : %u, pending : %u\n",
+			    credit_charge, conn->outstanding_credits);
+		ret = 1;
+	} else {
+		conn->outstanding_credits += credit_charge;
+		work->credit_charge = credit_charge;
+	}
+
+	spin_unlock(&conn->credits_lock);
+
+	return ret;
+}
+
+/*
+ * Verify that the sequence number(s) consumed by an incoming request fall
+ * within the connection's command sequence window and are not a replay, then
+ * remove them from the window. Returns 0 if the request
+ * may proceed, or 1 if it is invalid and the connection must be torn down.
+ */
+static int smb2_check_sequence_number(struct ksmbd_work *work,
+				      struct smb2_hdr *hdr)
+{
+	struct ksmbd_conn *conn = work->conn;
+	u64 mid = le64_to_cpu(hdr->MessageId);
+	unsigned short charge;
+	u64 i;
+	int ret = 0;
+
+	/* An SMB2 CANCEL consumes no sequence number. */
+	if (hdr->Command == SMB2_CANCEL)
+		return 0;
+
+	/*
+	 * A multi-credit request consumes CreditCharge consecutive sequence
+	 * numbers; every other request consumes exactly one.
+	 */
+	charge = le16_to_cpu(hdr->CreditCharge);
+	if (!(conn->vals->req_capabilities & SMB2_GLOBAL_CAP_LARGE_MTU) ||
+	    charge == 0)
+		charge = 1;
+
+	/* The 64-bit sequence number space must not wrap. */
+	if (mid + charge < mid) {
+		pr_err("SMB2 sequence number wrapped (mid %llu charge %u)\n",
+		       mid, charge);
+		return 1;
+	}
+
+	spin_lock(&conn->credits_lock);
+
+	/* The whole range must lie within the granted window... */
+	if (mid < conn->seq_low || mid + charge > conn->seq_high) {
+		ksmbd_debug(SMB,
+			    "MessageId %llu (charge %u) outside command window [%llu, %llu)\n",
+			    mid, charge, conn->seq_low, conn->seq_high);
+		ret = 1;
+		goto out;
+	}
+
+	/* ...and none of it may have been consumed already (replay). */
+	for (i = mid; i < mid + charge; i++) {
+		if (!test_bit(i & (KSMBD_CMD_SEQ_WINDOW - 1), conn->seq_bitmap)) {
+			ksmbd_debug(SMB,
+				    "replayed sequence number %llu (mid %llu charge %u)\n",
+				    i, mid, charge);
+			ret = 1;
+			goto out;
+		}
+	}
+
+	/* Consume the sequence numbers and slide the low edge forward. */
+	for (i = mid; i < mid + charge; i++)
+		__clear_bit(i & (KSMBD_CMD_SEQ_WINDOW - 1), conn->seq_bitmap);
+	while (conn->seq_low < conn->seq_high &&
+	       !test_bit(conn->seq_low & (KSMBD_CMD_SEQ_WINDOW - 1),
+			 conn->seq_bitmap))
+		conn->seq_low++;
+out:
+	spin_unlock(&conn->credits_lock);
+	return ret;
+}
+
+int ksmbd_smb2_check_message(struct ksmbd_work *work)
+{
+	struct smb2_pdu *pdu = ksmbd_req_buf_next(work);
+	struct smb2_hdr *hdr = &pdu->hdr;
+	int command;
+	__u32 clc_len;  /* calculated length */
+	__u32 len = get_rfc1002_len(work->request_buf);
+	__u32 req_struct_size, next_cmd = le32_to_cpu(hdr->NextCommand);
+
+	if ((u64)work->next_smb2_rcv_hdr_off + next_cmd > len) {
+		pr_err("next command(%u) offset exceeds smb msg size\n",
+				next_cmd);
+		return 1;
+	}
+
+	if (next_cmd > 0)
+		len = next_cmd;
+	else if (work->next_smb2_rcv_hdr_off)
+		len -= work->next_smb2_rcv_hdr_off;
+
+	if (check_smb2_hdr(hdr))
+		return 1;
+
+	if (hdr->StructureSize != SMB2_HEADER_STRUCTURE_SIZE) {
+		ksmbd_debug(SMB, "Illegal structure size %u\n",
+			    le16_to_cpu(hdr->StructureSize));
+		return 1;
+	}
+
+	command = le16_to_cpu(hdr->Command);
+	if (command >= NUMBER_OF_SMB2_COMMANDS) {
+		ksmbd_debug(SMB, "Illegal SMB2 command %d\n", command);
+		return 1;
+	}
+
+	if (len < __SMB2_HEADER_STRUCTURE_SIZE + sizeof(__le16)) {
+		ksmbd_debug(SMB, "Message is too small for StructureSize2\n");
+		return 1;
+	}
+
+	if (smb2_req_struct_sizes[command] != pdu->StructureSize2) {
+		if (!(command == SMB2_OPLOCK_BREAK_HE &&
+		    (le16_to_cpu(pdu->StructureSize2) == OP_BREAK_STRUCT_SIZE_20 ||
+		    le16_to_cpu(pdu->StructureSize2) == OP_BREAK_STRUCT_SIZE_21))) {
+			/* special case for SMB2.1 lease break message */
+			ksmbd_debug(SMB,
+				"Illegal request size %u for command %d\n",
+				le16_to_cpu(pdu->StructureSize2), command);
+			return 1;
+		}
+	}
+
+	req_struct_size = le16_to_cpu(pdu->StructureSize2) +
+		__SMB2_HEADER_STRUCTURE_SIZE;
+	if (command == SMB2_LOCK_HE)
+		req_struct_size -= sizeof(struct smb2_lock_element);
+
+	if (req_struct_size > len + 1)
+		return 1;
+
+	if (smb2_calc_size(hdr, &clc_len))
+		return 1;
+
+	if (len != clc_len) {
+		/* client can return one byte more due to implied bcc[0] */
+		if (clc_len == len + 1)
+			goto validate_credit;
+
+		/*
+		 * Some windows servers (win2016) will pad also the final
+		 * PDU in a compound to 8 bytes.
+		 */
+		if (ALIGN(clc_len, 8) == len)
+			goto validate_credit;
+
+		/*
+		 * SMB2 NEGOTIATE request will be validated when message
+		 * handling proceeds.
+		 */
+		if (command == SMB2_NEGOTIATE_HE)
+			goto validate_credit;
+
+		/*
+		 * Allow a message that padded to 8byte boundary.
+		 * Linux 4.19.217 with smb 3.0.2 are sometimes
+		 * sending messages where the cls_len is exactly
+		 * 8 bytes less than len.
+		 */
+		if (clc_len < len && (len - clc_len) <= 8)
+			goto validate_credit;
+
+		pr_err_ratelimited(
+			    "cli req too short, len %d not %d. cmd:%d mid:%llu\n",
+			    len, clc_len, command,
+			    le64_to_cpu(hdr->MessageId));
+
+		return 1;
+	}
+
+validate_credit:
+	if ((work->conn->vals->req_capabilities & SMB2_GLOBAL_CAP_LARGE_MTU) &&
+	    smb2_validate_credit_charge(work, hdr))
+		return 1;
+
+	/*
+	 * A sequence number violation (out of window or a replay) is a
+	 * protocol error. tear the connection down rather than
+	 * keep accepting requests on it.
+	 */
+	if (smb2_check_sequence_number(work, hdr)) {
+		ksmbd_conn_set_exiting(work->conn);
+		return 1;
+	}
+
+	return 0;
+}
+
+int smb2_negotiate_request(struct ksmbd_work *work)
+{
+	return ksmbd_smb_negotiate_common(work, SMB2_NEGOTIATE_HE);
+}