diff options
Diffstat (limited to 'fs/smb/server/smb2misc.c')
-rw-r--r-- | fs/smb/server/smb2misc.c | 461 |
1 files changed, 461 insertions, 0 deletions
diff --git a/fs/smb/server/smb2misc.c b/fs/smb/server/smb2misc.c new file mode 100644 index 0000000000..03dded29a9 --- /dev/null +++ b/fs/smb/server/smb2misc.c @@ -0,0 +1,461 @@ +// 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 "nterr.h" +#include "smb_common.h" +#include "smbstatus.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 = le16_to_cpu(((struct smb2_tree_connect_req *)hdr)->PathOffset); + *len = le16_to_cpu(((struct smb2_tree_connect_req *)hdr)->PathLength); + break; + case SMB2_CREATE: + { + unsigned short int name_off = + le16_to_cpu(((struct smb2_create_req *)hdr)->NameOffset); + 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 = le16_to_cpu(((struct smb2_query_info_req *)hdr)->InputBufferOffset); + *len = le32_to_cpu(((struct smb2_query_info_req *)hdr)->InputBufferLength); + break; + case SMB2_SET_INFO: + *off = le16_to_cpu(((struct smb2_set_info_req *)hdr)->BufferOffset); + *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 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 = le16_to_cpu(((struct smb2_query_directory_req *)hdr)->FileNameOffset); + *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 = le32_to_cpu(((struct smb2_ioctl_req *)hdr)->InputOffset); + *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); +} |