// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2016 Namjae Jeon <[email protected]>
* Copyright (C) 2018 Samsung Electronics Co., Ltd.
*/
#include "glob.h"
#include "nterr.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) +
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_conn *conn,
struct smb2_hdr *hdr)
{
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);
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;
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 (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->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU) &&
smb2_validate_credit_charge(work->conn, hdr))
return 1;
return 0;
}
int smb2_negotiate_request(struct ksmbd_work *work)
{
return ksmbd_smb_negotiate_common(work, SMB2_NEGOTIATE_HE);
}
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