xref: /illumos-gate/usr/src/uts/common/fs/smbsrv/smb_negotiate.c (revision 98cadd320d4521e7438bc624f89adef498589add)
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 (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
23  * Copyright 2012 Nexenta Systems, Inc.  All rights reserved.
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 smb.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 <netinet/in.h>
193 #include <smbsrv/smb_kproto.h>
194 #include <smbsrv/smbinfo.h>
195 
196 static smb_xlate_t smb_dialect[] = {
197 	{ DIALECT_UNKNOWN,		"DIALECT_UNKNOWN" },
198 	{ PC_NETWORK_PROGRAM_1_0,	"PC NETWORK PROGRAM 1.0" },
199 	{ PCLAN1_0,			"PCLAN1.0" },
200 	{ MICROSOFT_NETWORKS_1_03,	"MICROSOFT NETWORKS 1.03" },
201 	{ MICROSOFT_NETWORKS_3_0,	"MICROSOFT NETWORKS 3.0" },
202 	{ LANMAN1_0,			"LANMAN1.0" },
203 	{ LM1_2X002,			"LM1.2X002" },
204 	{ DOS_LM1_2X002,		"DOS LM1.2X002" },
205 	{ DOS_LANMAN2_1,		"DOS LANMAN2.1" },
206 	{ LANMAN2_1,			"LANMAN2.1" },
207 	{ Windows_for_Workgroups_3_1a,	"Windows for Workgroups 3.1a" },
208 	{ NT_LM_0_12,			"NT LM 0.12" }
209 };
210 
211 /*
212  * Maximum buffer size for DOS: chosen to be the same as NT.
213  * Do not change this value, DOS is very sensitive to it.
214  */
215 #define	SMB_DOS_MAXBUF			0x1104
216 
217 /*
218  * The DOS TCP rcvbuf is set to 8700 because DOS 6.1 seems to have problems
219  * with other values. DOS 6.1 seems to depend on a window value of 8700 to
220  * send the next set of data. If we return a window value of 40KB, after
221  * sending 8700 bytes of data, it will start the next set of data from 40KB
222  * instead of 8.7k. Why 8.7k? We have no idea; it is the value that NT uses.
223  * September 2000.
224  *
225  * IR104720 Increased smb_nt_tcp_rcvbuf from 40KB to just under 1MB to allow
226  * for a larger TCP window sizei based on observations of Windows 2000 and
227  * performance testing. March 2003.
228  */
229 static uint32_t	smb_dos_tcp_rcvbuf = 8700;
230 static uint32_t	smb_nt_tcp_rcvbuf = 1048560;	/* scale factor of 4 */
231 
232 static int smb_xlate_dialect(const char *);
233 
234 int smb_cap_passthru = 1;
235 
236 smb_sdrc_t
237 smb_pre_negotiate(smb_request_t *sr)
238 {
239 	smb_arg_negotiate_t	*negprot;
240 	int			dialect;
241 	int			pos;
242 	int			rc = 0;
243 
244 	negprot = smb_srm_zalloc(sr, sizeof (smb_arg_negotiate_t));
245 	negprot->ni_index = -1;
246 	sr->sr_negprot = negprot;
247 
248 	for (pos = 0; smbsr_decode_data_avail(sr); pos++) {
249 		if (smbsr_decode_data(sr, "%L", sr, &negprot->ni_name) != 0) {
250 			smbsr_error(sr, 0, ERRSRV, ERRerror);
251 			rc = -1;
252 			break;
253 		}
254 
255 		if ((dialect = smb_xlate_dialect(negprot->ni_name)) < 0)
256 			continue;
257 
258 		if (negprot->ni_dialect < dialect) {
259 			negprot->ni_dialect = dialect;
260 			negprot->ni_index = pos;
261 		}
262 	}
263 
264 	DTRACE_SMB_2(op__Negotiate__start, smb_request_t *, sr,
265 	    smb_arg_negotiate_t, negprot);
266 	smb_rwx_rwenter(&sr->session->s_lock, RW_WRITER);
267 	return ((rc == 0) ? SDRC_SUCCESS : SDRC_ERROR);
268 }
269 
270 void
271 smb_post_negotiate(smb_request_t *sr)
272 {
273 	smb_arg_negotiate_t	*negprot = sr->sr_negprot;
274 
275 	DTRACE_SMB_2(op__Negotiate__done, smb_request_t *, sr,
276 	    smb_arg_negotiate_t, negprot);
277 	smb_rwx_rwexit(&sr->session->s_lock);
278 
279 	bzero(negprot, sizeof (smb_arg_negotiate_t));
280 }
281 
282 smb_sdrc_t
283 smb_com_negotiate(smb_request_t *sr)
284 {
285 	smb_arg_negotiate_t	*negprot = sr->sr_negprot;
286 	uint16_t		secmode;
287 	uint16_t		rawmode = 0;
288 	uint32_t		sesskey;
289 	char			ipaddr_buf[INET6_ADDRSTRLEN];
290 	char			*nbdomain;
291 	uint8_t			*wcbuf;
292 	int			wclen;
293 	smb_msgbuf_t		mb;
294 	int			rc;
295 
296 	if (sr->session->s_state != SMB_SESSION_STATE_ESTABLISHED) {
297 		/* The protocol has already been negotiated. */
298 		smbsr_error(sr, 0, ERRSRV, ERRerror);
299 		return (SDRC_ERROR);
300 	}
301 
302 	sr->session->secmode = NEGOTIATE_SECURITY_CHALLENGE_RESPONSE |
303 	    NEGOTIATE_SECURITY_USER_LEVEL;
304 	secmode = sr->session->secmode;
305 	sesskey = sr->session->sesskey;
306 
307 	(void) microtime(&negprot->ni_servertime);
308 	negprot->ni_tzcorrection = sr->sr_gmtoff / 60;
309 	negprot->ni_maxmpxcount = sr->sr_cfg->skc_maxworkers;
310 	negprot->ni_keylen = SMB_CHALLENGE_SZ;
311 	bcopy(&sr->session->challenge_key, negprot->ni_key, SMB_CHALLENGE_SZ);
312 	nbdomain = sr->sr_cfg->skc_nbdomain;
313 
314 	/*
315 	 * UNICODE support is required for long share names,
316 	 * long file names and streams.
317 	 */
318 	negprot->ni_capabilities = CAP_LARGE_FILES
319 	    | CAP_UNICODE
320 	    | CAP_NT_SMBS
321 	    | CAP_STATUS32
322 	    | CAP_NT_FIND
323 	    | CAP_LEVEL_II_OPLOCKS
324 	    | CAP_LOCK_AND_READ
325 	    | CAP_RPC_REMOTE_APIS
326 	    | CAP_LARGE_READX
327 	    | CAP_LARGE_WRITEX
328 	    | CAP_DFS;
329 
330 	if (smb_raw_mode) {
331 		negprot->ni_capabilities |= CAP_RAW_MODE;
332 		rawmode = 3;
333 	}
334 
335 	if (smb_cap_passthru)
336 		negprot->ni_capabilities |= CAP_INFOLEVEL_PASSTHRU;
337 	else
338 		cmn_err(CE_NOTE, "smbsrv: cap passthru is %s",
339 		    (negprot->ni_capabilities & CAP_INFOLEVEL_PASSTHRU) ?
340 		    "enabled" : "disabled");
341 
342 	(void) smb_inet_ntop(&sr->session->ipaddr, ipaddr_buf,
343 	    SMB_IPSTRLEN(sr->session->ipaddr.a_family));
344 
345 	switch (negprot->ni_dialect) {
346 	case PC_NETWORK_PROGRAM_1_0:	/* core */
347 		(void) ksocket_setsockopt(sr->session->sock, SOL_SOCKET,
348 		    SO_RCVBUF, (const void *)&smb_dos_tcp_rcvbuf,
349 		    sizeof (smb_dos_tcp_rcvbuf), CRED());
350 		rc = smbsr_encode_result(sr, 1, 0, "bww", 1,
351 		    negprot->ni_index, 0);
352 		break;
353 
354 	case Windows_for_Workgroups_3_1a:
355 	case PCLAN1_0:
356 	case MICROSOFT_NETWORKS_1_03:
357 	case MICROSOFT_NETWORKS_3_0:
358 	case LANMAN1_0:
359 	case LM1_2X002:
360 	case DOS_LM1_2X002:
361 		(void) ksocket_setsockopt(sr->session->sock, SOL_SOCKET,
362 		    SO_RCVBUF, (const void *)&smb_dos_tcp_rcvbuf,
363 		    sizeof (smb_dos_tcp_rcvbuf), CRED());
364 		sr->smb_flg |= SMB_FLAGS_LOCK_AND_READ_OK;
365 		rc = smbsr_encode_result(sr, 13, VAR_BCC,
366 		    "bwwwwwwlYww2.w#c",
367 		    13,				/* wct */
368 		    negprot->ni_index,		/* dialect index */
369 		    secmode,			/* security mode */
370 		    SMB_DOS_MAXBUF,		/* max buffer size */
371 		    1,				/* max MPX */
372 		    1,				/* max VCs */
373 		    rawmode,			/* read/write raw (s/b 3) */
374 		    sesskey,			/* session key */
375 		    negprot->ni_servertime.tv_sec, /* server date/time */
376 		    negprot->ni_tzcorrection,
377 		    (uint16_t)negprot->ni_keylen, /* encryption key length */
378 						/* reserved field handled 2. */
379 		    VAR_BCC,
380 		    (int)negprot->ni_keylen,
381 		    negprot->ni_key);		/* encryption key */
382 		break;
383 
384 	case DOS_LANMAN2_1:
385 	case LANMAN2_1:
386 		(void) ksocket_setsockopt(sr->session->sock, SOL_SOCKET,
387 		    SO_RCVBUF, (const void *)&smb_dos_tcp_rcvbuf,
388 		    sizeof (smb_dos_tcp_rcvbuf), CRED());
389 		sr->smb_flg |= SMB_FLAGS_LOCK_AND_READ_OK;
390 		rc = smbsr_encode_result(sr, 13, VAR_BCC,
391 		    "bwwwwwwlYww2.w#cs",
392 		    13,				/* wct */
393 		    negprot->ni_index,		/* dialect index */
394 		    secmode,			/* security mode */
395 		    SMB_DOS_MAXBUF,		/* max buffer size */
396 		    1,				/* max MPX */
397 		    1,				/* max VCs */
398 		    rawmode,			/* read/write raw (s/b 3) */
399 		    sesskey,			/* session key */
400 		    negprot->ni_servertime.tv_sec, /* server date/time */
401 		    negprot->ni_tzcorrection,
402 		    (uint16_t)negprot->ni_keylen, /* encryption key length */
403 						/* reserved field handled 2. */
404 		    VAR_BCC,
405 		    (int)negprot->ni_keylen,
406 		    negprot->ni_key,		/* encryption key */
407 		    nbdomain);
408 		break;
409 
410 	case NT_LM_0_12:
411 		(void) ksocket_setsockopt(sr->session->sock, SOL_SOCKET,
412 		    SO_RCVBUF, (const void *)&smb_nt_tcp_rcvbuf,
413 		    sizeof (smb_nt_tcp_rcvbuf), CRED());
414 
415 		/*
416 		 * Turn off Extended Security Negotiation
417 		 */
418 		sr->smb_flg2 &= ~SMB_FLAGS2_EXT_SEC;
419 
420 		/*
421 		 * Allow SMB signatures if security challenge response enabled
422 		 */
423 		if ((secmode & NEGOTIATE_SECURITY_CHALLENGE_RESPONSE) &&
424 		    sr->sr_cfg->skc_signing_enable) {
425 			secmode |= NEGOTIATE_SECURITY_SIGNATURES_ENABLED;
426 			if (sr->sr_cfg->skc_signing_required)
427 				secmode |=
428 				    NEGOTIATE_SECURITY_SIGNATURES_REQUIRED;
429 
430 			sr->session->secmode = secmode;
431 		}
432 
433 		/*
434 		 * nbdomain is not expected to be aligned.
435 		 * Use temporary buffer to avoid alignment padding
436 		 */
437 		wclen = smb_wcequiv_strlen(nbdomain) + sizeof (smb_wchar_t);
438 		wcbuf = smb_srm_zalloc(sr, wclen);
439 		smb_msgbuf_init(&mb, wcbuf, wclen, SMB_MSGBUF_UNICODE);
440 		if (smb_msgbuf_encode(&mb, "U", nbdomain) < 0) {
441 			smb_msgbuf_term(&mb);
442 			smbsr_error(sr, 0, ERRSRV, ERRerror);
443 			return (SDRC_ERROR);
444 		}
445 
446 		rc = smbsr_encode_result(sr, 17, VAR_BCC,
447 		    "bwbwwllllTwbw#c#c",
448 		    17,				/* wct */
449 		    negprot->ni_index,		/* dialect index */
450 		    secmode,			/* security mode */
451 		    negprot->ni_maxmpxcount,	/* max MPX */
452 		    1,				/* max VCs */
453 		    (DWORD)smb_maxbufsize,	/* max buffer size */
454 		    0xFFFF,			/* max raw size */
455 		    sesskey,			/* session key */
456 		    negprot->ni_capabilities,
457 		    &negprot->ni_servertime,	/* system time */
458 		    negprot->ni_tzcorrection,
459 		    negprot->ni_keylen,		/* encryption key length */
460 		    VAR_BCC,
461 		    (int)negprot->ni_keylen,
462 		    negprot->ni_key,		/* encryption key */
463 		    wclen,
464 		    wcbuf);			/* nbdomain (unicode) */
465 
466 		smb_msgbuf_term(&mb);
467 		break;
468 
469 	default:
470 		rc = smbsr_encode_result(sr, 1, 0, "bww", 1, -1, 0);
471 		return ((rc == 0) ? SDRC_SUCCESS : SDRC_ERROR);
472 	}
473 
474 	if (rc != 0)
475 		return (SDRC_ERROR);
476 
477 	/*
478 	 * Save the agreed dialect. Note that this value is also
479 	 * used to detect and reject attempts to re-negotiate.
480 	 */
481 	sr->session->dialect = negprot->ni_dialect;
482 	sr->session->s_state = SMB_SESSION_STATE_NEGOTIATED;
483 	return (SDRC_SUCCESS);
484 }
485 
486 static int
487 smb_xlate_dialect(const char *dialect)
488 {
489 	smb_xlate_t	*dp;
490 	int		i;
491 
492 	for (i = 0; i < sizeof (smb_dialect) / sizeof (smb_dialect[0]); ++i) {
493 		dp = &smb_dialect[i];
494 
495 		if (strcmp(dp->str, dialect) == 0)
496 			return (dp->code);
497 	}
498 
499 	return (-1);
500 }
501