xref: /titanic_41/usr/src/uts/common/fs/smbsrv/smb_negotiate.c (revision f0325ac466f51612f2c496cdf286e41597ee9b43)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 /*
27  * Notes on the virtual circuit (VC) values in the SMB Negotiate
28  * response and SessionSetupAndx request.
29  *
30  * A virtual circuit (VC) represents a connection between a client and a
31  * server using a reliable, session oriented transport protocol, such as
32  * NetBIOS or TCP/IP. Originally, each SMB session was restricted to a
33  * single underlying transport connection, i.e. a single NetBIOS session,
34  * which limited performance for raw data transfers.
35  *
36  * The intention behind multiple VCs was to improve performance by
37  * allowing parallelism over each NetBIOS session. For example, raw data
38  * could be transmitted using a different VC from other types of SMB
39  * requests to remove the interleaving restriction while a raw transfer
40  * is in progress. So the MaxNumberVcs field was added to the negotiate
41  * response to make the number of VCs configurable and to allow servers
42  * to specify how many they were prepared to support per session
43  * connection. This turned out to be difficult to manage and, with
44  * technology improvements, it has become obsolete.
45  *
46  * Servers should set the MaxNumberVcs value in the Negotiate response
47  * to 1. Clients should probably ignore it. If a server receives a
48  * SessionSetupAndx with a VC value of 0, it should close all other
49  * VCs to that client. If it receives a non-zero VC, it should leave
50  * other VCs in tact.
51  *
52  */
53 
54 /*
55  * SMB: negotiate
56  *
57  * Client Request                Description
58  * ============================  =======================================
59  *
60  * UCHAR WordCount;              Count of parameter words = 0
61  * USHORT ByteCount;             Count of data bytes; min = 2
62  * struct {
63  *    UCHAR BufferFormat;        0x02 -- Dialect
64  *    UCHAR DialectName[];       ASCII null-terminated string
65  * } Dialects[];
66  *
67  * The Client sends a list of dialects that it can communicate with.  The
68  * response is a selection of one of those dialects (numbered 0 through n)
69  * or -1 (hex FFFF) indicating that none of the dialects were acceptable.
70  * The negotiate message is binding on the virtual circuit and must be
71  * sent.  One and only one negotiate message may be sent, subsequent
72  * negotiate requests will be rejected with an error response and no action
73  * will be taken.
74  *
75  * The protocol does not impose any particular structure to the dialect
76  * strings.  Implementors of particular protocols may choose to include,
77  * for example, version numbers in the string.
78  *
79  * If the server does not understand any of the dialect strings, or if PC
80  * NETWORK PROGRAM 1.0 is the chosen dialect, the response format is
81  *
82  * Server Response               Description
83  * ============================  =======================================
84  *
85  * UCHAR WordCount;              Count of parameter words = 1
86  * USHORT DialectIndex;          Index of selected dialect
87  * USHORT ByteCount;             Count of data bytes = 0
88  *
89  * If the chosen dialect is greater than core up to and including
90  * LANMAN2.1, the protocol response format is
91  *
92  * Server Response               Description
93  * ============================  =======================================
94  *
95  * UCHAR WordCount;              Count of parameter words = 13
96  * USHORT  DialectIndex;         Index of selected dialect
97  * USHORT  SecurityMode;         Security mode:
98  *                               bit 0: 0 = share, 1 = user
99  *                               bit 1: 1 = use challenge/response
100  *                               authentication
101  * USHORT  MaxBufferSize;        Max transmit buffer size (>= 1024)
102  * USHORT  MaxMpxCount;          Max pending multiplexed requests
103  * USHORT  MaxNumberVcs;         Max VCs between client and server
104  * USHORT  RawMode;              Raw modes supported:
105  *                                bit 0: 1 = Read Raw supported
106  *                                bit 1: 1 = Write Raw supported
107  * ULONG SessionKey;             Unique token identifying this session
108  * SMB_TIME ServerTime;          Current time at server
109  * SMB_DATE ServerDate;          Current date at server
110  * USHORT ServerTimeZone;        Current time zone at server
111  * USHORT  EncryptionKeyLength;  MBZ if this is not LM2.1
112  * USHORT  Reserved;             MBZ
113  * USHORT  ByteCount             Count of data bytes
114  * UCHAR EncryptionKey[];        The challenge encryption key
115  * STRING PrimaryDomain[];       The server's primary domain
116  *
117  * MaxBufferSize is the size of the largest message which the client can
118  * legitimately send to the server
119  *
120  * If  bit0 of the Flags field is set in the negotiate response, this
121  * indicates the server supports the SMB_COM_LOCK_AND_READ and
122  * SMB_COM_WRITE_AND_UNLOCK client requests.
123  *
124  * If the SecurityMode field indicates the server is running in user mode,
125  * the client must send appropriate SMB_COM_SESSION_SETUP_ANDX requests
126  * before the server will allow the client to access resources.   If the
127  * SecurityMode fields indicates the client should use challenge/response
128  * authentication, the client should use the authentication mechanism
129  * specified in section 2.10.
130  *
131  * Clients should submit no more than MaxMpxCount distinct unanswered SMBs
132  * to the server when using multiplexed reads or writes (see sections 5.13
133  * and 5.25)
134  *
135  * Clients using the  "MICROSOFT NETWORKS 1.03" dialect use a different
136  * form of raw reads than documented here, and servers are better off
137  * setting RawMode in this response to 0 for such sessions.
138  *
139  * If the negotiated dialect is "DOS LANMAN2.1" or "LANMAN2.1", then
140  * PrimaryDomain string should be included in this response.
141  *
142  * If the negotiated dialect is NT LM 0.12, the response format is
143  *
144  * Server Response            Description
145  * ========================== =========================================
146  *
147  * UCHAR WordCount;           Count of parameter words = 17
148  * USHORT DialectIndex;       Index of selected dialect
149  * UCHAR SecurityMode;        Security mode:
150  *                             bit 0: 0 = share, 1 = user
151  *                             bit 1: 1 = encrypt passwords
152  * USHORT MaxMpxCount;        Max pending multiplexed requests
153  * USHORT MaxNumberVcs;       Max VCs between client and server
154  * ULONG MaxBufferSize;       Max transmit buffer size
155  * ULONG MaxRawSize;          Maximum raw buffer size
156  * ULONG SessionKey;          Unique token identifying this session
157  * ULONG Capabilities;        Server capabilities
158  * ULONG SystemTimeLow;       System (UTC) time of the server (low).
159  * ULONG SystemTimeHigh;      System (UTC) time of the server (high).
160  * USHORT ServerTimeZone;     Time zone of server (min from UTC)
161  * UCHAR EncryptionKeyLength; Length of encryption key.
162  * USHORT ByteCount;          Count of data bytes
163  * UCHAR EncryptionKey[];     The challenge encryption key
164  * UCHAR OemDomainName[];     The name of the domain (in OEM chars)
165  *
166  * In addition to the definitions above, MaxBufferSize is the size of the
167  * largest message which the client can legitimately send to the server.
168  * If the client is using a connectionless protocol,  MaxBufferSize must be
169  * set to the smaller of the server's internal buffer size and the amount
170  * of data which can be placed in a response packet.
171  *
172  * MaxRawSize specifies the maximum message size the server can send or
173  * receive for SMB_COM_WRITE_RAW or SMB_COM_READ_RAW.
174  *
175  * Connectionless clients must set Sid to 0 in the SMB request header.
176  *
177  * Capabilities allows the server to tell the client what it supports.
178  * The bit definitions defined in cifs.h. Bit 0x2000 used to be set in
179  * the negotiate response capabilities but it caused problems with
180  * Windows 2000. It is probably not valid, it doesn't appear in the
181  * CIFS spec.
182  *
183  * 4.1.1.1   Errors
184  *
185  * SUCCESS/SUCCESS
186  * ERRSRV/ERRerror
187  */
188 #include <sys/types.h>
189 #include <sys/strsubr.h>
190 #include <sys/socketvar.h>
191 #include <sys/socket.h>
192 #include <sys/random.h>
193 #include <netinet/in.h>
194 #include <smbsrv/smb_incl.h>
195 #include <smbsrv/smbinfo.h>
196 #include <smbsrv/smb_i18n.h>
197 
198 /*
199  * Maximum buffer size for DOS: chosen to be the same as NT.
200  * Do not change this value, DOS is very sensitive to it.
201  */
202 #define	SMB_DOS_MAXBUF			0x1104
203 
204 /*
205  * The DOS TCP rcvbuf is set to 8700 because DOS 6.1 seems to have problems
206  * with other values. DOS 6.1 seems to depend on a window value of 8700 to
207  * send the next set of data. If we return a window value of 40KB, after
208  * sending 8700 bytes of data, it will start the next set of data from 40KB
209  * instead of 8.7k. Why 8.7k? We have no idea; it is the value that NT uses.
210  * September 2000.
211  *
212  * IR104720 Increased smb_nt_tcp_rcvbuf from 40KB to just under 1MB to allow
213  * for a larger TCP window sizei based on observations of Windows 2000 and
214  * performance testing. March 2003.
215  */
216 static uint32_t	smb_dos_tcp_rcvbuf = 8700;
217 static uint32_t	smb_nt_tcp_rcvbuf = 1048560;	/* scale factor of 4 */
218 
219 static void smb_get_security_info(smb_request_t *, unsigned short *,
220     unsigned char *, unsigned char *, uint32_t *);
221 
222 /*
223  * Function: int smb_com_negotiate(struct smb_request *)
224  */
225 smb_sdrc_t
226 smb_pre_negotiate(smb_request_t *sr)
227 {
228 	DTRACE_SMB_1(op__Negotiate__start, smb_request_t *, sr);
229 	return (SDRC_SUCCESS);
230 }
231 
232 void
233 smb_post_negotiate(smb_request_t *sr)
234 {
235 	DTRACE_SMB_1(op__Negotiate__done, smb_request_t *, sr);
236 }
237 
238 smb_sdrc_t
239 smb_com_negotiate(smb_request_t *sr)
240 {
241 	int			dialect = 0;
242 	int			this_dialect;
243 	unsigned char		keylen;
244 	int			sel_pos = -1;
245 	int			pos;
246 	char 			key[32];
247 	char			*p;
248 	timestruc_t		time_val;
249 	unsigned short		secmode;
250 	uint32_t		sesskey;
251 	uint32_t		capabilities = 0;
252 	int			rc;
253 	unsigned short		max_mpx_count;
254 	int16_t			tz_correction;
255 	char			ipaddr_buf[INET6_ADDRSTRLEN];
256 	char			*tmpbuf;
257 	int			buflen;
258 	smb_msgbuf_t		mb;
259 
260 	if (sr->session->s_state != SMB_SESSION_STATE_ESTABLISHED) {
261 		/* The protocol has already been negotiated. */
262 		smbsr_error(sr, 0, ERRSRV, ERRerror);
263 		return (SDRC_ERROR);
264 	}
265 
266 	for (pos = 0;
267 	    sr->smb_data.chain_offset < sr->smb_data.max_bytes;
268 	    pos++) {
269 		if (smb_mbc_decodef(&sr->smb_data, "%L", sr, &p) != 0) {
270 			smbsr_error(sr, 0, ERRSRV, ERRerror);
271 			return (SDRC_ERROR);
272 		}
273 
274 		this_dialect = smb_xlate_dialect_str_to_cd(p);
275 
276 		if (this_dialect < 0)
277 			continue;
278 
279 		if (dialect < this_dialect) {
280 			dialect = this_dialect;
281 			sel_pos = pos;
282 		}
283 	}
284 
285 	smb_get_security_info(sr, &secmode, (unsigned char *)key,
286 	    &keylen, &sesskey);
287 
288 	(void) microtime(&time_val);
289 	tz_correction = sr->sr_gmtoff / 60;
290 
291 	switch (dialect) {
292 	case PC_NETWORK_PROGRAM_1_0:	/* core */
293 		(void) ksocket_setsockopt(sr->session->sock, SOL_SOCKET,
294 		    SO_RCVBUF, (const void *)&smb_dos_tcp_rcvbuf,
295 		    sizeof (smb_dos_tcp_rcvbuf), CRED());
296 		rc = smbsr_encode_result(sr, 1, 0, "bww", 1, sel_pos, 0);
297 		break;
298 
299 	case Windows_for_Workgroups_3_1a:
300 	case PCLAN1_0:
301 	case MICROSOFT_NETWORKS_1_03:
302 	case MICROSOFT_NETWORKS_3_0:
303 	case LANMAN1_0:
304 	case LM1_2X002:
305 	case DOS_LM1_2X002:
306 		(void) ksocket_setsockopt(sr->session->sock, SOL_SOCKET,
307 		    SO_RCVBUF, (const void *)&smb_dos_tcp_rcvbuf,
308 		    sizeof (smb_dos_tcp_rcvbuf), CRED());
309 		sr->smb_flg |= SMB_FLAGS_LOCK_AND_READ_OK;
310 		rc = smbsr_encode_result(sr, 13, VAR_BCC,
311 		    "bwwwwwwlYww2.w#c",
312 		    13,		/* wct */
313 		    sel_pos,	/* dialect index */
314 		    secmode,		/* security mode */
315 		    SMB_DOS_MAXBUF,	/* max buffer size */
316 		    1,		/* max MPX (temporary) */
317 		    1,		/* max VCs (temporary, ambiguous) */
318 		    3,		/* raw mode (s/b 3) */
319 		    sesskey,	/* session key */
320 		    time_val.tv_sec, /* server time/date */
321 		    tz_correction,
322 		    (short)keylen,	/* Encryption Key Length */
323 				/* reserved field handled 2. */
324 		    VAR_BCC,
325 		    (int)keylen,
326 		    key);		/* encryption key */
327 		break;
328 
329 	case DOS_LANMAN2_1:
330 	case LANMAN2_1:
331 		(void) ksocket_setsockopt(sr->session->sock, SOL_SOCKET,
332 		    SO_RCVBUF, (const void *)&smb_dos_tcp_rcvbuf,
333 		    sizeof (smb_dos_tcp_rcvbuf), CRED());
334 		sr->smb_flg |= SMB_FLAGS_LOCK_AND_READ_OK;
335 		rc = smbsr_encode_result(sr, 13, VAR_BCC,
336 		    "bwwwwwwlYww2.w#cs",
337 		    13,		/* wct */
338 		    sel_pos,	/* dialect index */
339 		    secmode,		/* security mode */
340 		    SMB_DOS_MAXBUF,	/* max buffer size */
341 		    1,		/* max MPX (temporary) */
342 		    1,		/* max VCs (temporary, ambiguous) */
343 		    3,		/* raw mode (s/b 3) */
344 		    sesskey,	/* session key */
345 		    time_val.tv_sec, /* server time/date */
346 		    tz_correction,
347 		    (short)keylen,	/* Encryption Key Length */
348 				/* reserved field handled 2. */
349 		    VAR_BCC,
350 		    (int)keylen,
351 		    key,		/* encryption key */
352 		    sr->sr_cfg->skc_nbdomain);
353 		break;
354 
355 	case NT_LM_0_12:
356 		(void) ksocket_setsockopt(sr->session->sock, SOL_SOCKET,
357 		    SO_RCVBUF, (const void *)&smb_nt_tcp_rcvbuf,
358 		    sizeof (smb_nt_tcp_rcvbuf), CRED());
359 		/*
360 		 * UNICODE support is required for long share names,
361 		 * long file names and streams.
362 		 */
363 		capabilities = CAP_LARGE_FILES
364 		    | CAP_UNICODE
365 		    | CAP_NT_SMBS
366 		    | CAP_STATUS32
367 		    | CAP_NT_FIND
368 		    | CAP_RAW_MODE
369 		    | CAP_LEVEL_II_OPLOCKS
370 		    | CAP_LOCK_AND_READ
371 		    | CAP_RPC_REMOTE_APIS
372 		    | CAP_LARGE_READX
373 		    | CAP_LARGE_WRITEX;
374 
375 		/*
376 		 * Turn off Extended Security Negotiation
377 		 */
378 		sr->smb_flg2 &= ~SMB_FLAGS2_EXT_SEC;
379 
380 		/*
381 		 * Allow SMB signatures if security challenge response enabled
382 		 */
383 		if ((secmode & NEGOTIATE_SECURITY_CHALLENGE_RESPONSE) &&
384 		    sr->sr_cfg->skc_signing_enable) {
385 			secmode |= NEGOTIATE_SECURITY_SIGNATURES_ENABLED;
386 			if (sr->sr_cfg->skc_signing_required)
387 				secmode |=
388 				    NEGOTIATE_SECURITY_SIGNATURES_REQUIRED;
389 
390 			sr->session->secmode = secmode;
391 		}
392 		(void) smb_inet_ntop(&sr->session->ipaddr, ipaddr_buf,
393 		    SMB_IPSTRLEN(sr->session->ipaddr.a_family));
394 
395 		max_mpx_count = sr->sr_cfg->skc_maxworkers;
396 
397 		/*
398 		 * skc_nbdomain is not expected to be aligned.
399 		 * Use temporary buffer to avoid alignment padding
400 		 */
401 		buflen = mts_wcequiv_strlen(sr->sr_cfg->skc_nbdomain) +
402 		    sizeof (mts_wchar_t);
403 		tmpbuf = kmem_zalloc(buflen, KM_SLEEP);
404 		smb_msgbuf_init(&mb, (uint8_t *)tmpbuf, buflen,
405 		    SMB_MSGBUF_UNICODE);
406 		if (smb_msgbuf_encode(&mb, "U",
407 		    sr->sr_cfg->skc_nbdomain) < 0) {
408 			smb_msgbuf_term(&mb);
409 			kmem_free(tmpbuf, buflen);
410 			smbsr_error(sr, 0, ERRSRV, ERRerror);
411 			return (SDRC_ERROR);
412 		}
413 
414 		rc = smbsr_encode_result(sr, 17, VAR_BCC,
415 		    "bwbwwllllTwbw#c#c",
416 		    17,		/* wct */
417 		    sel_pos,	/* dialect index */
418 		    secmode,	/* security mode */
419 		    max_mpx_count,		/* max MPX (temporary) */
420 		    1,		/* max VCs (temporary, ambiguous) */
421 		    (DWORD)smb_maxbufsize,	/* max buffer size */
422 		    0xFFFF,	/* max raw size */
423 		    sesskey,	/* session key */
424 		    capabilities,
425 		    &time_val,	/* system time */
426 		    tz_correction,
427 		    keylen,	/* Encryption Key Length */
428 		    VAR_BCC,
429 		    (int)keylen,
430 		    key,	/* encryption key */
431 		    buflen,
432 		    tmpbuf);	/* skc_nbdomain */
433 
434 		smb_msgbuf_term(&mb);
435 		kmem_free(tmpbuf, buflen);
436 		break;
437 
438 	default:
439 		sel_pos = -1;
440 		rc = smbsr_encode_result(sr, 1, 0, "bww", 1, sel_pos, 0);
441 		return ((rc == 0) ? SDRC_SUCCESS : SDRC_ERROR);
442 	}
443 
444 	if (rc != 0)
445 		return (SDRC_ERROR);
446 
447 	/*
448 	 * Save the agreed dialect. Note that this value is also
449 	 * used to detect and reject attempts to re-negotiate.
450 	 */
451 	sr->session->dialect = dialect;
452 	sr->session->s_state = SMB_SESSION_STATE_NEGOTIATED;
453 	return (SDRC_SUCCESS);
454 }
455 
456 static void
457 smb_get_security_info(
458     struct smb_request *sr,
459     unsigned short *secmode,
460     unsigned char *key,
461     unsigned char *keylen,
462     uint32_t *sesskey)
463 {
464 	uchar_t tmp_key[8];
465 
466 	(void) random_get_pseudo_bytes(tmp_key, 8);
467 	bcopy(tmp_key, &sr->session->challenge_key, 8);
468 	sr->session->challenge_len = 8;
469 	*keylen = 8;
470 	bcopy(tmp_key, key, 8);
471 
472 	sr->session->secmode = NEGOTIATE_SECURITY_CHALLENGE_RESPONSE|
473 	    NEGOTIATE_SECURITY_USER_LEVEL;
474 
475 	(void) random_get_pseudo_bytes(tmp_key, 4);
476 	sr->session->sesskey = tmp_key[0] | tmp_key[1] << 8 |
477 	    tmp_key[2] << 16 | tmp_key[3] << 24;
478 
479 	*secmode = sr->session->secmode;
480 	*sesskey = sr->session->sesskey;
481 }
482