linux/fs/smb/client/smb1misc.c

// SPDX-License-Identifier: LGPL-2.1
/*
 *
 *   Copyright (C) International Business Machines  Corp., 2002,2008
 *   Author(s): Steve French (sfrench@us.ibm.com)
 *
 */

#include "smb1proto.h"
#include "smberr.h"
#include "nterr.h"
#include "cifs_debug.h"

/* NB: MID can not be set if treeCon not passed in, in that
   case it is responsibility of caller to set the mid */
unsigned int
header_assemble(struct smb_hdr *buffer, char smb_command,
		const struct cifs_tcon *treeCon, int word_count
		/* length of fixed section (word count) in two byte units  */)
{
	unsigned int in_len;
	char *temp = (char *) buffer;

	memset(temp, 0, 256); /* bigger than MAX_CIFS_HDR_SIZE */

	in_len = (2 * word_count) + sizeof(struct smb_hdr) +
		2 /* for bcc field itself */;

	buffer->Protocol[0] = 0xFF;
	buffer->Protocol[1] = 'S';
	buffer->Protocol[2] = 'M';
	buffer->Protocol[3] = 'B';
	buffer->Command = smb_command;
	buffer->Flags = 0x00;	/* case sensitive */
	buffer->Flags2 = SMBFLG2_KNOWS_LONG_NAMES;
	buffer->Pid = cpu_to_le16((__u16)current->tgid);
	buffer->PidHigh = cpu_to_le16((__u16)(current->tgid >> 16));
	if (treeCon) {
		buffer->Tid = treeCon->tid;
		if (treeCon->ses) {
			if (treeCon->ses->capabilities & CAP_UNICODE)
				buffer->Flags2 |= SMBFLG2_UNICODE;
			if (treeCon->ses->capabilities & CAP_STATUS32)
				buffer->Flags2 |= SMBFLG2_ERR_STATUS;

			/* Uid is not converted */
			buffer->Uid = treeCon->ses->Suid;
			if (treeCon->ses->server)
				buffer->Mid = get_next_mid(treeCon->ses->server);
		}
		if (treeCon->Flags & SMB_SHARE_IS_IN_DFS)
			buffer->Flags2 |= SMBFLG2_DFS;
		if (treeCon->nocase)
			buffer->Flags  |= SMBFLG_CASELESS;
		if ((treeCon->ses) && (treeCon->ses->server))
			if (treeCon->ses->server->sign)
				buffer->Flags2 |= SMBFLG2_SECURITY_SIGNATURE;
	}

/*  endian conversion of flags is now done just before sending */
	buffer->WordCount = (char) word_count;
	return in_len;
}

bool
is_valid_oplock_break(char *buffer, struct TCP_Server_Info *srv)
{
	struct smb_hdr *buf = (struct smb_hdr *)buffer;
	struct smb_com_lock_req *pSMB = (struct smb_com_lock_req *)buf;
	struct TCP_Server_Info *pserver;
	struct cifs_ses *ses;
	struct cifs_tcon *tcon;
	struct cifsInodeInfo *pCifsInode;
	struct cifsFileInfo *netfile;

	cifs_dbg(FYI, "Checking for oplock break or dnotify response\n");
	if ((pSMB->hdr.Command == SMB_COM_NT_TRANSACT) &&
	   (pSMB->hdr.Flags & SMBFLG_RESPONSE)) {
		struct smb_com_transaction_change_notify_rsp *pSMBr =
			(struct smb_com_transaction_change_notify_rsp *)buf;
		struct file_notify_information *pnotify;
		__u32 data_offset = 0;
		size_t len = srv->total_read - srv->pdu_size;

		if (get_bcc(buf) > sizeof(struct file_notify_information)) {
			data_offset = le32_to_cpu(pSMBr->DataOffset);

			if (data_offset >
			    len - sizeof(struct file_notify_information)) {
				cifs_dbg(FYI, "Invalid data_offset %u\n",
					 data_offset);
				return true;
			}
			pnotify = (struct file_notify_information *)
				((char *)&pSMBr->hdr.Protocol + data_offset);
			cifs_dbg(FYI, "dnotify on %s Action: 0x%x\n",
				 pnotify->FileName, pnotify->Action);
			/*   cifs_dump_mem("Rcvd notify Data: ",buf,
				sizeof(struct smb_hdr)+60); */
			return true;
		}
		if (pSMBr->hdr.Status.CifsError) {
			cifs_dbg(FYI, "notify err 0x%x\n",
				 pSMBr->hdr.Status.CifsError);
			return true;
		}
		return false;
	}
	if (pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
		return false;
	if (pSMB->hdr.Flags & SMBFLG_RESPONSE) {
		/* no sense logging error on invalid handle on oplock
		   break - harmless race between close request and oplock
		   break response is expected from time to time writing out
		   large dirty files cached on the client */
		if ((NT_STATUS_INVALID_HANDLE) ==
		   le32_to_cpu(pSMB->hdr.Status.CifsError)) {
			cifs_dbg(FYI, "Invalid handle on oplock break\n");
			return true;
		} else if (ERRbadfid ==
		   le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
			return true;
		} else {
			return false; /* on valid oplock brk we get "request" */
		}
	}
	if (pSMB->hdr.WordCount != 8)
		return false;

	cifs_dbg(FYI, "oplock type 0x%x level 0x%x\n",
		 pSMB->LockType, pSMB->OplockLevel);
	if (!(pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE))
		return false;

	/* If server is a channel, select the primary channel */
	pserver = SERVER_IS_CHAN(srv) ? srv->primary_server : srv;

	/* look up tcon based on tid & uid */
	spin_lock(&cifs_tcp_ses_lock);
	list_for_each_entry(ses, &pserver->smb_ses_list, smb_ses_list) {
		if (cifs_ses_exiting(ses))
			continue;
		list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
			if (tcon->tid != buf->Tid)
				continue;

			cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
			spin_lock(&tcon->open_file_lock);
			list_for_each_entry(netfile, &tcon->openFileList, tlist) {
				if (pSMB->Fid != netfile->fid.netfid)
					continue;

				cifs_dbg(FYI, "file id match, oplock break\n");
				pCifsInode = CIFS_I(d_inode(netfile->dentry));

				set_bit(CIFS_INODE_PENDING_OPLOCK_BREAK,
					&pCifsInode->flags);

				netfile->oplock_epoch = 0;
				netfile->oplock_level = pSMB->OplockLevel;
				netfile->oplock_break_cancelled = false;
				cifs_queue_oplock_break(netfile);

				spin_unlock(&tcon->open_file_lock);
				spin_unlock(&cifs_tcp_ses_lock);
				return true;
			}
			spin_unlock(&tcon->open_file_lock);
			spin_unlock(&cifs_tcp_ses_lock);
			cifs_dbg(FYI, "No matching file for oplock break\n");
			return true;
		}
	}
	spin_unlock(&cifs_tcp_ses_lock);
	cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
	return true;
}

/*
 * 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
 */
unsigned int
smbCalcSize(void *buf)
{
	struct smb_hdr *ptr = buf;
	return (sizeof(struct smb_hdr) + (2 * ptr->WordCount) +
		2 /* size of the bcc field */ + get_bcc(ptr));
}