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CIFS: use DFS pathnames in SMB2+ Create requests

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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@suse.com>
Acked-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
This commit is contained in:
Aurelien Aptel 2017-02-22 14:47:17 +01:00 committed by Steve French
parent b9043cc5b9
commit f0712928be
1 changed files with 79 additions and 15 deletions
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94
fs/cifs/smb2pdu.c
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@ -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(&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);
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;