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-rw-r--r--fs/smb/server/smb2misc.c461
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 000000000..03dded29a
--- /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);
+}
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