1/*
  2 *   fs/cifs/cifs_spnego.c -- SPNEGO upcall management for CIFS
  3 *
  4 *   Copyright (c) 2007 Red Hat, Inc.
  5 *   Author(s): Jeff Layton (jlayton@redhat.com)
  6 *
  7 *   This library is free software; you can redistribute it and/or modify
  8 *   it under the terms of the GNU Lesser General Public License as published
  9 *   by the Free Software Foundation; either version 2.1 of the License, or
 10 *   (at your option) any later version.
 11 *
 12 *   This library is distributed in the hope that it will be useful,
 13 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 14 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 15 *   the GNU Lesser General Public License for more details.
 16 *
 17 *   You should have received a copy of the GNU Lesser General Public License
 18 *   along with this library; if not, write to the Free Software
 19 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 20 */
 21
 22#include <linux/list.h>
 23#include <linux/slab.h>
 24#include <linux/string.h>
 25#include <keys/user-type.h>
 26#include <linux/key-type.h>
 27#include <linux/inet.h>
 28#include "cifsglob.h"
 29#include "cifs_spnego.h"
 30#include "cifs_debug.h"
 31
 32/* create a new cifs key */
 33static int
 34cifs_spnego_key_instantiate(struct key *key, const void *data, size_t datalen)
 35{
 36	char *payload;
 37	int ret;
 38
 39	ret = -ENOMEM;
 40	payload = kmalloc(datalen, GFP_KERNEL);
 41	if (!payload)
 42		goto error;
 43
 44	/* attach the data */
 45	memcpy(payload, data, datalen);
 46	key->payload.data = payload;
 47	ret = 0;
 48
 49error:
 50	return ret;
 51}
 52
 53static void
 54cifs_spnego_key_destroy(struct key *key)
 55{
 56	kfree(key->payload.data);
 57}
 58
 59
 60/*
 61 * keytype for CIFS spnego keys
 62 */
 63struct key_type cifs_spnego_key_type = {
 64	.name		= "cifs.spnego",
 65	.instantiate	= cifs_spnego_key_instantiate,
 66	.match		= user_match,
 67	.destroy	= cifs_spnego_key_destroy,
 68	.describe	= user_describe,
 69};
 70
 71/* length of longest version string e.g.  strlen("ver=0xFF") */
 72#define MAX_VER_STR_LEN		8
 73
 74/* length of longest security mechanism name, eg in future could have
 75 * strlen(";sec=ntlmsspi") */
 76#define MAX_MECH_STR_LEN	13
 77
 78/* strlen of "host=" */
 79#define HOST_KEY_LEN		5
 80
 81/* strlen of ";ip4=" or ";ip6=" */
 82#define IP_KEY_LEN		5
 83
 84/* strlen of ";uid=0x" */
 85#define UID_KEY_LEN		7
 86
 87/* strlen of ";creduid=0x" */
 88#define CREDUID_KEY_LEN		11
 89
 90/* strlen of ";user=" */
 91#define USER_KEY_LEN		6
 92
 93/* strlen of ";pid=0x" */
 94#define PID_KEY_LEN		7
 95
 96/* get a key struct with a SPNEGO security blob, suitable for session setup */
 97struct key *
 98cifs_get_spnego_key(struct cifs_ses *sesInfo)
 99{
100	struct TCP_Server_Info *server = sesInfo->server;
101	struct sockaddr_in *sa = (struct sockaddr_in *) &server->dstaddr;
102	struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *) &server->dstaddr;
103	char *description, *dp;
104	size_t desc_len;
105	struct key *spnego_key;
106	const char *hostname = server->hostname;
107
108	/* length of fields (with semicolons): ver=0xyz ip4=ipaddress
109	   host=hostname sec=mechanism uid=0xFF user=username */
110	desc_len = MAX_VER_STR_LEN +
111		   HOST_KEY_LEN + strlen(hostname) +
112		   IP_KEY_LEN + INET6_ADDRSTRLEN +
113		   MAX_MECH_STR_LEN +
114		   UID_KEY_LEN + (sizeof(uid_t) * 2) +
115		   CREDUID_KEY_LEN + (sizeof(uid_t) * 2) +
116		   USER_KEY_LEN + strlen(sesInfo->user_name) +
117		   PID_KEY_LEN + (sizeof(pid_t) * 2) + 1;
118
119	spnego_key = ERR_PTR(-ENOMEM);
120	description = kzalloc(desc_len, GFP_KERNEL);
121	if (description == NULL)
122		goto out;
123
124	dp = description;
125	/* start with version and hostname portion of UNC string */
126	spnego_key = ERR_PTR(-EINVAL);
127	sprintf(dp, "ver=0x%x;host=%s;", CIFS_SPNEGO_UPCALL_VERSION,
128		hostname);
129	dp = description + strlen(description);
130
131	/* add the server address */
132	if (server->dstaddr.ss_family == AF_INET)
133		sprintf(dp, "ip4=%pI4", &sa->sin_addr);
134	else if (server->dstaddr.ss_family == AF_INET6)
135		sprintf(dp, "ip6=%pI6", &sa6->sin6_addr);
136	else
137		goto out;
138
139	dp = description + strlen(description);
140
141	/* for now, only sec=krb5 and sec=mskrb5 are valid */
142	if (server->sec_kerberos)
143		sprintf(dp, ";sec=krb5");
144	else if (server->sec_mskerberos)
145		sprintf(dp, ";sec=mskrb5");
146	else
147		goto out;
148
149	dp = description + strlen(description);
150	sprintf(dp, ";uid=0x%x", sesInfo->linux_uid);
151
152	dp = description + strlen(description);
153	sprintf(dp, ";creduid=0x%x", sesInfo->cred_uid);
154
155	dp = description + strlen(description);
156	sprintf(dp, ";user=%s", sesInfo->user_name);
157
158	dp = description + strlen(description);
159	sprintf(dp, ";pid=0x%x", current->pid);
160
161	cFYI(1, "key description = %s", description);
162	spnego_key = request_key(&cifs_spnego_key_type, description, "");
163
164#ifdef CONFIG_CIFS_DEBUG2
165	if (cifsFYI && !IS_ERR(spnego_key)) {
166		struct cifs_spnego_msg *msg = spnego_key->payload.data;
167		cifs_dump_mem("SPNEGO reply blob:", msg->data, min(1024U,
168				msg->secblob_len + msg->sesskey_len));
169	}
170#endif /* CONFIG_CIFS_DEBUG2 */
171
172out:
173	kfree(description);
174	return spnego_key;
175}