From f0712928be1a66c99c35f871b4df7fa23ec1574a Mon Sep 17 00:00:00 2001 From: Aurelien Aptel Date: Wed, 22 Feb 2017 14:47:17 +0100 Subject: [PATCH] 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: "\\" *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 Acked-by: Pavel Shilovsky Signed-off-by: Steve French --- fs/cifs/smb2pdu.c | 96 +++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 80 insertions(+), 16 deletions(-) diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c index 2fd93eeed15a..2069431b32e3 100644 --- a/fs/cifs/smb2pdu.c +++ b/fs/cifs/smb2pdu.c @@ -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, @@ -1576,30 +1621,49 @@ 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; -- 2.20.1