2017-02-28 10:40 GMT-08:00 Aurelien Aptel <aaptel@xxxxxxxx>:
> 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: Aurelien Aptel <aaptel@xxxxxxxx>
> ---
> fs/cifs/smb2pdu.c | 93 +++++++++++++++++++++++++++++++++++++++++++++----------
> 1 file changed, 77 insertions(+), 16 deletions(-)
>
> diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
> index 2fd93ee..059da05 100644
> --- a/fs/cifs/smb2pdu.c
> +++ b/fs/cifs/smb2pdu.c
> @@ -1528,6 +1528,48 @@ 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;
> + 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;
> +
> + cifs_strtoUTF16(*out_path, treename, treename_len, load_nls_default());
> + UniStrcat(*out_path, sep);
> + UniStrcat(*out_path, path);
> +
> + return 0;
> +}
> +
> int
> SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
> __u8 *oplock, struct smb2_file_all_info *buf,
> @@ -1576,30 +1618,49 @@ 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;
> -
> - /* 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_path = kzalloc(copy_size, GFP_KERNEL);
> - if (!copy_path)
> - return -ENOMEM;
> - memcpy((char *)copy_path, (const char *)path,
> - uni_path_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(©_path, ©_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);
> + if (uni_path_len % 8 != 0) {
> + copy_size = roundup(uni_path_len, 8);
> + copy_path = kzalloc(copy_size, GFP_KERNEL);
> + if (!copy_path)
> + return -ENOMEM;
> + memcpy((char *)copy_path, (const char *)path,
> + uni_path_len);
> + uni_path_len = copy_size;
> + path = copy_path;
> + }
> }
>
> iov[1].iov_len = uni_path_len;
> --
> 2.10.2
>
> --
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Acked-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>
--
Best regards,
Pavel Shilovsky
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