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CIFS: implement get_dfs_refer for SMB2+

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in SMB2+ the get_dfs_refer operation uses a FSCTL. The request can be
made on any Tree Connection according to the specs. Since Samba only
accepted it on an IPC connection until recently, try that first.

https://lists.samba.org/archive/samba-technical/2017-February/118859.html

3.2.4.20.3 Application Requests DFS Referral Information:
> The client MUST search for an existing Session and TreeConnect to any
> share on the server identified by ServerName for the user identified by
> UserCredentials. If no Session and TreeConnect are found, the client
> MUST establish a new Session and TreeConnect to IPC$ on the target
> server as described in section 3.2.4.2 using the supplied ServerName and
> UserCredentials.

Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Steve French <smfrench@gmail.com>
This commit is contained in:
Aurelien Aptel 2017-02-13 16:16:49 +01:00 committed by Steve French
parent f0712928be
commit 9d49640a21
2 changed files with 109 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

101
fs/cifs/smb2ops.c
View file

@ -1104,6 +1104,103 @@ smb2_new_lease_key(struct cifs_fid *fid)
generate_random_uuid(fid->lease_key);
}
static int
smb2_get_dfs_refer(const unsigned int xid, struct cifs_ses *ses,
const char *search_name,
struct dfs_info3_param **target_nodes,
unsigned int *num_of_nodes,
const struct nls_table *nls_codepage, int remap)
{
int rc;
__le16 *utf16_path = NULL;
int utf16_path_len = 0;
struct cifs_tcon *tcon;
struct fsctl_get_dfs_referral_req *dfs_req = NULL;
struct get_dfs_referral_rsp *dfs_rsp = NULL;
u32 dfs_req_size = 0, dfs_rsp_size = 0;
cifs_dbg(FYI, "smb2_get_dfs_refer path <%s>\n", search_name);
/*
* Use any tcon from the current session. Here, the first one.
*/
spin_lock(&cifs_tcp_ses_lock);
tcon = list_first_entry_or_null(&ses->tcon_list, struct cifs_tcon,
tcon_list);
if (tcon)
tcon->tc_count++;
spin_unlock(&cifs_tcp_ses_lock);
if (!tcon) {
cifs_dbg(VFS, "session %p has no tcon available for a dfs referral request\n",
ses);
rc = -ENOTCONN;
goto out;
}
utf16_path = cifs_strndup_to_utf16(search_name, PATH_MAX,
&utf16_path_len,
nls_codepage, remap);
if (!utf16_path) {
rc = -ENOMEM;
goto out;
}
dfs_req_size = sizeof(*dfs_req) + utf16_path_len;
dfs_req = kzalloc(dfs_req_size, GFP_KERNEL);
if (!dfs_req) {
rc = -ENOMEM;
goto out;
}
/* Highest DFS referral version understood */
dfs_req->MaxReferralLevel = DFS_VERSION;
/* Path to resolve in an UTF-16 null-terminated string */
memcpy(dfs_req->RequestFileName, utf16_path, utf16_path_len);
do {
/* try first with IPC */
rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
FSCTL_DFS_GET_REFERRALS,
true /* is_fsctl */, true /* use_ipc */,
(char *)dfs_req, dfs_req_size,
(char **)&dfs_rsp, &dfs_rsp_size);
if (rc == -ENOTCONN) {
/* try with normal tcon */
rc = SMB2_ioctl(xid, tcon, NO_FILE_ID, NO_FILE_ID,
FSCTL_DFS_GET_REFERRALS,
true /* is_fsctl */, false /*use_ipc*/,
(char *)dfs_req, dfs_req_size,
(char **)&dfs_rsp, &dfs_rsp_size);
}
} while (rc == -EAGAIN);
if (rc) {
cifs_dbg(VFS, "ioctl error in smb2_get_dfs_refer rc=%d\n", rc);
goto out;
}
rc = parse_dfs_referrals(dfs_rsp, dfs_rsp_size,
num_of_nodes, target_nodes,
nls_codepage, remap, search_name,
true /* is_unicode */);
if (rc) {
cifs_dbg(VFS, "parse error in smb2_get_dfs_refer rc=%d\n", rc);
goto out;
}
out:
if (tcon) {
spin_lock(&cifs_tcp_ses_lock);
tcon->tc_count--;
spin_unlock(&cifs_tcp_ses_lock);
}
kfree(utf16_path);
kfree(dfs_req);
kfree(dfs_rsp);
return rc;
}
#define SMB2_SYMLINK_STRUCT_SIZE \
(sizeof(struct smb2_err_rsp) - 1 + sizeof(struct smb2_symlink_err_rsp))
@ -2283,6 +2380,7 @@ struct smb_version_operations smb20_operations = {
.clone_range = smb2_clone_range,
.wp_retry_size = smb2_wp_retry_size,
.dir_needs_close = smb2_dir_needs_close,
.get_dfs_refer = smb2_get_dfs_refer,
};
struct smb_version_operations smb21_operations = {
@ -2364,6 +2462,7 @@ struct smb_version_operations smb21_operations = {
.wp_retry_size = smb2_wp_retry_size,
.dir_needs_close = smb2_dir_needs_close,
.enum_snapshots = smb3_enum_snapshots,
.get_dfs_refer = smb2_get_dfs_refer,
};
struct smb_version_operations smb30_operations = {
@ -2455,6 +2554,7 @@ struct smb_version_operations smb30_operations = {
.free_transform_rq = smb3_free_transform_rq,
.is_transform_hdr = smb3_is_transform_hdr,
.receive_transform = smb3_receive_transform,
.get_dfs_refer = smb2_get_dfs_refer,
};
#ifdef CONFIG_CIFS_SMB311
@ -2547,6 +2647,7 @@ struct smb_version_operations smb311_operations = {
.free_transform_rq = smb3_free_transform_rq,
.is_transform_hdr = smb3_is_transform_hdr,
.receive_transform = smb3_receive_transform,
.get_dfs_refer = smb2_get_dfs_refer,
};
#endif /* CIFS_SMB311 */

8
fs/cifs/smb2pdu.h
View file

@ -695,6 +695,14 @@ struct fsctl_get_integrity_information_rsp {
/* Integrity flags for above */
#define FSCTL_INTEGRITY_FLAG_CHECKSUM_ENFORCEMENT_OFF 0x00000001
/* See MS-DFSC 2.2.2 */
struct fsctl_get_dfs_referral_req {
__le16 MaxReferralLevel;
__u8 RequestFileName[];
} __packed;
/* DFS response is struct get_dfs_refer_rsp */
/* See MS-SMB2 2.2.31.3 */
struct network_resiliency_req {
__le32 Timeout;