Commit f0712928 authored by Aurelien Aptel's avatar Aurelien Aptel Committed by Steve French
Browse files

CIFS: use DFS pathnames in SMB2+ Create requests 



When connected to a DFS capable share, the client must set the
SMB2_FLAGS_DFS_OPERATIONS flag in the SMB2 header and use
DFS path names: "<server>\<share>\<path>" *without* leading \\.

Sources:

[MS-SMB2] 3.2.5.5 Receiving an SMB2 TREE_CONNECT Response
> TreeConnect.IsDfsShare MUST be set to TRUE, if the SMB2_SHARE_CAP_DFS
> bit is set in the Capabilities field of the response.

[MS-SMB2] 3.2.4.3 Application Requests Opening a File
> If TreeConnect.IsDfsShare is TRUE, the SMB2_FLAGS_DFS_OPERATIONS flag
> is set in the Flags field.

[MS-SMB2] 2.2.13 SMB2 CREATE Request, NameOffset:
> If SMB2_FLAGS_DFS_OPERATIONS is set in the Flags field of the SMB2
> header, the file name includes a prefix that will be processed during
> DFS name normalization as specified in section 3.3.5.9. Otherwise, the
> file name is relative to the share that is identified by the TreeId in
> the SMB2 header.

Signed-off-by: default avatarAurelien Aptel <aaptel@suse.com>
Acked-by: default avatarPavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: default avatarSteve French <smfrench@gmail.com>
parent b9043cc5

fs/cifs/smb2pdu.c

+80 −16
Original line number Diff line number Diff line
@@ -1528,6 +1528,51 @@ add_durable_context(struct kvec *iov, unsigned int *num_iovec, 
	return 0;

}



static int

alloc_path_with_tree_prefix(__le16 **out_path, int *out_size, int *out_len,

			    const char *treename, const __le16 *path)

{

	int treename_len, path_len;

	struct nls_table *cp;

	const __le16 sep[] = {cpu_to_le16('\\'), cpu_to_le16(0x0000)};



	/*

	 * skip leading "\\"

	 */

	treename_len = strlen(treename);

	if (treename_len < 2 || !(treename[0] == '\\' && treename[1] == '\\'))

		return -EINVAL;



	treename += 2;

	treename_len -= 2;



	path_len = UniStrnlen((wchar_t *)path, PATH_MAX);



	/*

	 * make room for one path separator between the treename and

	 * path

	 */

	*out_len = treename_len + 1 + path_len;



	/*

	 * final path needs to be null-terminated UTF16 with a

	 * size aligned to 8

	 */



	*out_size = roundup((*out_len+1)*2, 8);

	*out_path = kzalloc(*out_size, GFP_KERNEL);

	if (!*out_path)

		return -ENOMEM;



	cp = load_nls_default();

	cifs_strtoUTF16(*out_path, treename, treename_len, cp);

	UniStrcat(*out_path, sep);

	UniStrcat(*out_path, path);

	unload_nls(cp);



	return 0;

}



int

SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,

	  __u8 *oplock, struct smb2_file_all_info *buf,
@@ -1576,23 +1621,41 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path, 
	req->ShareAccess = FILE_SHARE_ALL_LE;

	req->CreateDisposition = cpu_to_le32(oparms->disposition);

	req->CreateOptions = cpu_to_le32(oparms->create_options & CREATE_OPTIONS_MASK);

	uni_path_len = (2 * UniStrnlen((wchar_t *)path, PATH_MAX)) + 2;

	/* do not count rfc1001 len field */

	req->NameOffset = cpu_to_le16(sizeof(struct smb2_create_req) - 4);



	iov[0].iov_base = (char *)req;

	/* 4 for rfc1002 length field */

	iov[0].iov_len = get_rfc1002_length(req) + 4;

	/* -1 since last byte is buf[0] which is sent below (path) */

	iov[0].iov_len--;



	req->NameOffset = cpu_to_le16(sizeof(struct smb2_create_req) - 4);



	/* [MS-SMB2] 2.2.13 NameOffset:

	 * If SMB2_FLAGS_DFS_OPERATIONS is set in the Flags field of

	 * the SMB2 header, the file name includes a prefix that will

	 * be processed during DFS name normalization as specified in

	 * section 3.3.5.9. Otherwise, the file name is relative to

	 * the share that is identified by the TreeId in the SMB2

	 * header.

	 */

	if (tcon->share_flags & SHI1005_FLAGS_DFS) {

		int name_len;



		req->hdr.sync_hdr.Flags |= SMB2_FLAGS_DFS_OPERATIONS;

		rc = alloc_path_with_tree_prefix(&copy_path, &copy_size,

						 &name_len,

						 tcon->treeName, path);

		if (rc)

			return rc;

		req->NameLength = cpu_to_le16(name_len * 2);

		uni_path_len = copy_size;

		path = copy_path;

	} else {

		uni_path_len = (2 * UniStrnlen((wchar_t *)path, PATH_MAX)) + 2;

		/* MUST set path len (NameLength) to 0 opening root of share */

		req->NameLength = cpu_to_le16(uni_path_len - 2);

	/* -1 since last byte is buf[0] which is sent below (path) */

	iov[0].iov_len--;

		if (uni_path_len % 8 != 0) {

		copy_size = uni_path_len / 8 * 8;

		if (copy_size < uni_path_len)

			copy_size += 8;



			copy_size = roundup(uni_path_len, 8);

			copy_path = kzalloc(copy_size, GFP_KERNEL);

			if (!copy_path)

				return -ENOMEM;
@@ -1601,6 +1664,7 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path, 
			uni_path_len = copy_size;

			path = copy_path;

		}

	}



	iov[1].iov_len = uni_path_len;

	iov[1].iov_base = path;

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