• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /*
2  *   fs/cifs/smb2transport.c
3  *
4  *   Copyright (C) International Business Machines  Corp., 2002, 2011
5  *                 Etersoft, 2012
6  *   Author(s): Steve French (sfrench@us.ibm.com)
7  *              Jeremy Allison (jra@samba.org) 2006
8  *              Pavel Shilovsky (pshilovsky@samba.org) 2012
9  *
10  *   This library is free software; you can redistribute it and/or modify
11  *   it under the terms of the GNU Lesser General Public License as published
12  *   by the Free Software Foundation; either version 2.1 of the License, or
13  *   (at your option) any later version.
14  *
15  *   This library is distributed in the hope that it will be useful,
16  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
17  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
18  *   the GNU Lesser General Public License for more details.
19  *
20  *   You should have received a copy of the GNU Lesser General Public License
21  *   along with this library; if not, write to the Free Software
22  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23  */
24 
25 #include <linux/fs.h>
26 #include <linux/list.h>
27 #include <linux/wait.h>
28 #include <linux/net.h>
29 #include <linux/delay.h>
30 #include <linux/uaccess.h>
31 #include <asm/processor.h>
32 #include <linux/mempool.h>
33 #include <linux/highmem.h>
34 #include "smb2pdu.h"
35 #include "cifsglob.h"
36 #include "cifsproto.h"
37 #include "smb2proto.h"
38 #include "cifs_debug.h"
39 #include "smb2status.h"
40 #include "smb2glob.h"
41 
42 int
smb2_calc_signature(struct smb_rqst * rqst,struct TCP_Server_Info * server)43 smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
44 {
45 	int i, rc;
46 	unsigned char smb2_signature[SMB2_HMACSHA256_SIZE];
47 	unsigned char *sigptr = smb2_signature;
48 	struct kvec *iov = rqst->rq_iov;
49 	int n_vec = rqst->rq_nvec;
50 	struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
51 
52 	memset(smb2_signature, 0x0, SMB2_HMACSHA256_SIZE);
53 	memset(smb2_pdu->Signature, 0x0, SMB2_SIGNATURE_SIZE);
54 
55 	rc = crypto_shash_setkey(server->secmech.hmacsha256,
56 		server->session_key.response, SMB2_NTLMV2_SESSKEY_SIZE);
57 	if (rc) {
58 		cifs_dbg(VFS, "%s: Could not update with response\n", __func__);
59 		return rc;
60 	}
61 
62 	rc = crypto_shash_init(&server->secmech.sdeschmacsha256->shash);
63 	if (rc) {
64 		cifs_dbg(VFS, "%s: Could not init md5\n", __func__);
65 		return rc;
66 	}
67 
68 	for (i = 0; i < n_vec; i++) {
69 		if (iov[i].iov_len == 0)
70 			continue;
71 		if (iov[i].iov_base == NULL) {
72 			cifs_dbg(VFS, "null iovec entry\n");
73 			return -EIO;
74 		}
75 		/*
76 		 * The first entry includes a length field (which does not get
77 		 * signed that occupies the first 4 bytes before the header).
78 		 */
79 		if (i == 0) {
80 			if (iov[0].iov_len <= 8) /* cmd field at offset 9 */
81 				break; /* nothing to sign or corrupt header */
82 			rc =
83 			crypto_shash_update(
84 				&server->secmech.sdeschmacsha256->shash,
85 				iov[i].iov_base + 4, iov[i].iov_len - 4);
86 		} else {
87 			rc =
88 			crypto_shash_update(
89 				&server->secmech.sdeschmacsha256->shash,
90 				iov[i].iov_base, iov[i].iov_len);
91 		}
92 		if (rc) {
93 			cifs_dbg(VFS, "%s: Could not update with payload\n",
94 				 __func__);
95 			return rc;
96 		}
97 	}
98 
99 	/* now hash over the rq_pages array */
100 	for (i = 0; i < rqst->rq_npages; i++) {
101 		struct kvec p_iov;
102 
103 		cifs_rqst_page_to_kvec(rqst, i, &p_iov);
104 		crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
105 					p_iov.iov_base, p_iov.iov_len);
106 		kunmap(rqst->rq_pages[i]);
107 	}
108 
109 	rc = crypto_shash_final(&server->secmech.sdeschmacsha256->shash,
110 				sigptr);
111 	if (rc)
112 		cifs_dbg(VFS, "%s: Could not generate sha256 hash\n", __func__);
113 
114 	memcpy(smb2_pdu->Signature, sigptr, SMB2_SIGNATURE_SIZE);
115 
116 	return rc;
117 }
118 
119 int
smb3_calc_signature(struct smb_rqst * rqst,struct TCP_Server_Info * server)120 smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
121 {
122 	cifs_dbg(FYI, "smb3 signatures not supported yet\n");
123 	return -EOPNOTSUPP;
124 }
125 
126 /* must be called with server->srv_mutex held */
127 static int
smb2_sign_rqst(struct smb_rqst * rqst,struct TCP_Server_Info * server)128 smb2_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server)
129 {
130 	int rc = 0;
131 	struct smb2_hdr *smb2_pdu = rqst->rq_iov[0].iov_base;
132 
133 	if (!(smb2_pdu->Flags & SMB2_FLAGS_SIGNED) ||
134 	    server->tcpStatus == CifsNeedNegotiate)
135 		return rc;
136 
137 	if (!server->session_estab) {
138 		strncpy(smb2_pdu->Signature, "BSRSPYL", 8);
139 		return rc;
140 	}
141 
142 	rc = server->ops->calc_signature(rqst, server);
143 
144 	return rc;
145 }
146 
147 int
smb2_verify_signature(struct smb_rqst * rqst,struct TCP_Server_Info * server)148 smb2_verify_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
149 {
150 	unsigned int rc;
151 	char server_response_sig[16];
152 	struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
153 
154 	if ((smb2_pdu->Command == SMB2_NEGOTIATE) ||
155 	    (smb2_pdu->Command == SMB2_OPLOCK_BREAK) ||
156 	    (!server->session_estab))
157 		return 0;
158 
159 	/*
160 	 * BB what if signatures are supposed to be on for session but
161 	 * server does not send one? BB
162 	 */
163 
164 	/* Do not need to verify session setups with signature "BSRSPYL " */
165 	if (memcmp(smb2_pdu->Signature, "BSRSPYL ", 8) == 0)
166 		cifs_dbg(FYI, "dummy signature received for smb command 0x%x\n",
167 			 smb2_pdu->Command);
168 
169 	/*
170 	 * Save off the origiginal signature so we can modify the smb and check
171 	 * our calculated signature against what the server sent.
172 	 */
173 	memcpy(server_response_sig, smb2_pdu->Signature, SMB2_SIGNATURE_SIZE);
174 
175 	memset(smb2_pdu->Signature, 0, SMB2_SIGNATURE_SIZE);
176 
177 	mutex_lock(&server->srv_mutex);
178 	rc = server->ops->calc_signature(rqst, server);
179 	mutex_unlock(&server->srv_mutex);
180 
181 	if (rc)
182 		return rc;
183 
184 	if (memcmp(server_response_sig, smb2_pdu->Signature,
185 		   SMB2_SIGNATURE_SIZE))
186 		return -EACCES;
187 	else
188 		return 0;
189 }
190 
191 /*
192  * Set message id for the request. Should be called after wait_for_free_request
193  * and when srv_mutex is held.
194  */
195 static inline void
smb2_seq_num_into_buf(struct TCP_Server_Info * server,struct smb2_hdr * hdr)196 smb2_seq_num_into_buf(struct TCP_Server_Info *server, struct smb2_hdr *hdr)
197 {
198 	hdr->MessageId = get_next_mid(server);
199 }
200 
201 static struct mid_q_entry *
smb2_mid_entry_alloc(const struct smb2_hdr * smb_buffer,struct TCP_Server_Info * server)202 smb2_mid_entry_alloc(const struct smb2_hdr *smb_buffer,
203 		     struct TCP_Server_Info *server)
204 {
205 	struct mid_q_entry *temp;
206 
207 	if (server == NULL) {
208 		cifs_dbg(VFS, "Null TCP session in smb2_mid_entry_alloc\n");
209 		return NULL;
210 	}
211 
212 	temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
213 	if (temp == NULL)
214 		return temp;
215 	else {
216 		memset(temp, 0, sizeof(struct mid_q_entry));
217 		temp->mid = smb_buffer->MessageId;	/* always LE */
218 		temp->pid = current->pid;
219 		temp->command = smb_buffer->Command;	/* Always LE */
220 		temp->when_alloc = jiffies;
221 		temp->server = server;
222 
223 		/*
224 		 * The default is for the mid to be synchronous, so the
225 		 * default callback just wakes up the current task.
226 		 */
227 		temp->callback = cifs_wake_up_task;
228 		temp->callback_data = current;
229 	}
230 
231 	atomic_inc(&midCount);
232 	temp->mid_state = MID_REQUEST_ALLOCATED;
233 	return temp;
234 }
235 
236 static int
smb2_get_mid_entry(struct cifs_ses * ses,struct smb2_hdr * buf,struct mid_q_entry ** mid)237 smb2_get_mid_entry(struct cifs_ses *ses, struct smb2_hdr *buf,
238 		   struct mid_q_entry **mid)
239 {
240 	if (ses->server->tcpStatus == CifsExiting)
241 		return -ENOENT;
242 
243 	if (ses->server->tcpStatus == CifsNeedReconnect) {
244 		cifs_dbg(FYI, "tcp session dead - return to caller to retry\n");
245 		return -EAGAIN;
246 	}
247 
248 	if (ses->status != CifsGood) {
249 		/* check if SMB2 session is bad because we are setting it up */
250 		if ((buf->Command != SMB2_SESSION_SETUP) &&
251 		    (buf->Command != SMB2_NEGOTIATE))
252 			return -EAGAIN;
253 		/* else ok - we are setting up session */
254 	}
255 	*mid = smb2_mid_entry_alloc(buf, ses->server);
256 	if (*mid == NULL)
257 		return -ENOMEM;
258 	spin_lock(&GlobalMid_Lock);
259 	list_add_tail(&(*mid)->qhead, &ses->server->pending_mid_q);
260 	spin_unlock(&GlobalMid_Lock);
261 	return 0;
262 }
263 
264 int
smb2_check_receive(struct mid_q_entry * mid,struct TCP_Server_Info * server,bool log_error)265 smb2_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
266 		   bool log_error)
267 {
268 	unsigned int len = get_rfc1002_length(mid->resp_buf);
269 	struct kvec iov;
270 	struct smb_rqst rqst = { .rq_iov = &iov,
271 				 .rq_nvec = 1 };
272 
273 	iov.iov_base = (char *)mid->resp_buf;
274 	iov.iov_len = get_rfc1002_length(mid->resp_buf) + 4;
275 
276 	dump_smb(mid->resp_buf, min_t(u32, 80, len));
277 	/* convert the length into a more usable form */
278 	if ((len > 24) &&
279 	    (server->sec_mode & (SECMODE_SIGN_REQUIRED|SECMODE_SIGN_ENABLED))) {
280 		int rc;
281 
282 		rc = smb2_verify_signature(&rqst, server);
283 		if (rc)
284 			cifs_dbg(VFS, "SMB signature verification returned error = %d\n",
285 				 rc);
286 	}
287 
288 	return map_smb2_to_linux_error(mid->resp_buf, log_error);
289 }
290 
291 struct mid_q_entry *
smb2_setup_request(struct cifs_ses * ses,struct smb_rqst * rqst)292 smb2_setup_request(struct cifs_ses *ses, struct smb_rqst *rqst)
293 {
294 	int rc;
295 	struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
296 	struct mid_q_entry *mid;
297 
298 	smb2_seq_num_into_buf(ses->server, hdr);
299 
300 	rc = smb2_get_mid_entry(ses, hdr, &mid);
301 	if (rc)
302 		return ERR_PTR(rc);
303 	rc = smb2_sign_rqst(rqst, ses->server);
304 	if (rc) {
305 		cifs_delete_mid(mid);
306 		return ERR_PTR(rc);
307 	}
308 	return mid;
309 }
310 
311 struct mid_q_entry *
smb2_setup_async_request(struct TCP_Server_Info * server,struct smb_rqst * rqst)312 smb2_setup_async_request(struct TCP_Server_Info *server, struct smb_rqst *rqst)
313 {
314 	int rc;
315 	struct smb2_hdr *hdr = (struct smb2_hdr *)rqst->rq_iov[0].iov_base;
316 	struct mid_q_entry *mid;
317 
318 	smb2_seq_num_into_buf(server, hdr);
319 
320 	mid = smb2_mid_entry_alloc(hdr, server);
321 	if (mid == NULL)
322 		return ERR_PTR(-ENOMEM);
323 
324 	rc = smb2_sign_rqst(rqst, server);
325 	if (rc) {
326 		DeleteMidQEntry(mid);
327 		return ERR_PTR(rc);
328 	}
329 
330 	return mid;
331 }
332