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 * Copyright 2014 Nexenta Systems, Inc.  All rights reserved.
26 */
27
28#if defined(_KERNEL) || defined(_FAKE_KERNEL)
29#include <sys/types.h>
30#include <sys/sunddi.h>
31#else
32#include <string.h>
33#endif
34#include <smbsrv/string.h>
35#include <smbsrv/netbios.h>
36
37/*
38 * Routines than support name compression.
39 *
40 *   The NetBIOS name representation in all NetBIOS packets (for NAME,
41 *   SESSION, and DATAGRAM services) is defined in the Domain Name
42 *   Service RFC 883[3] as "compressed" name messages.  This format is
43 *   called "second-level encoding" in the section entitled
44 *   "Representation of NetBIOS Names" in the Concepts and Methods
45 *   document.
46 *
47 *   For ease of description, the first two paragraphs from page 31,
48 *   the section titled "Domain name representation and compression",
49 *   of RFC 883 are replicated here:
50 *
51 *        Domain names messages are expressed in terms of a sequence
52 *        of labels.  Each label is represented as a one octet length
53 *        field followed by that number of octets.  Since every domain
54 *        name ends with the null label of the root, a compressed
55 *        domain name is terminated by a length byte of zero.  The
56 *        high order two bits of the length field must be zero, and
57 *        the remaining six bits of the length field limit the label
58 *        to 63 octets or less.
59 *
60 *        To simplify implementations, the total length of label
61 *        octets and label length octets that make up a domain name is
62 *        restricted to 255 octets or less.
63 *
64 *   The following is the uncompressed representation of the NetBIOS name
65 *   "FRED ", which is the 4 ASCII characters, F, R, E, D, followed by 12
66 *   space characters (0x20).  This name has the SCOPE_ID: "NETBIOS.COM"
67 *
68 *           EGFCEFEECACACACACACACACACACACACA.NETBIOS.COM
69 *
70 *   This uncompressed representation of names is called "first-level
71 *   encoding" in the section entitled "Representation of NetBIOS Names"
72 *   in the Concepts and Methods document.
73 *
74 *   The following is a pictographic representation of the compressed
75 *   representation of the previous uncompressed Domain Name
76 *   representation.
77 *
78 *                        1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
79 *    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
80 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
81 *   |      0x20     |    E (0x45)   |    G (0x47)   |    F (0x46)   |
82 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
83 *   |    C (0x43)   |    E (0x45)   |    F (0x46)   |    E (0x45)   |
84 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
85 *   |    E (0x45)   |    C (0x43)   |    A (0x41)   |    C (0x43)   |
86 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
87 *   |    A (0x41)   |    C (0x43)   |    A (0x41)   |    C (0x43)   |
88 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
89 *   |    A (0x41)   |    C (0x43)   |    A (0x41)   |    C (0x43)   |
90 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
91 *   |    A (0x41)   |    C (0x43)   |    A (0x41)   |    C (0x43)   |
92 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
93 *   |    A (0x41)   |    C (0x43)   |    A (0x41)   |    C (0x43)   |
94 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
95 *   |    A (0x41)   |    C (0x43)   |    A (0x41)   |    C (0x43)   |
96 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
97 *   |    A (0X41)   |      0x07     |    N (0x4E)   |    E (0x45)   |
98 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
99 *   |    T (0x54)   |    B (0x42)   |    I (0x49)   |    O (0x4F)   |
100 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
101 *   |    S (0x53)   |      0x03     |    C (0x43)   |    O (0x4F)   |
102 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
103 *   |    M (0x4D)   |      0x00     |
104 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
105 *
106 *   Each section of a domain name is called a label [7 (page 31)].  A
107 *   label can be a maximum of 63 bytes.  The first byte of a label in
108 *   compressed representation is the number of bytes in the label.  For
109 *   the above example, the first 0x20 is the number of bytes in the
110 *   left-most label, EGFCEFEECACACACACACACACACACACACA, of the domain
111 *   name.  The bytes following the label length count are the characters
112 *   of the label.  The following labels are in sequence after the first
113 *   label, which is the encoded NetBIOS name, until a zero (0x00) length
114 *   count.  The zero length count represents the root label, which is
115 *   always null.
116 *
117 *   A label length count is actually a 6-bit field in the label length
118 *   field.  The most significant 2 bits of the field, bits 7 and 6, are
119 *   flags allowing an escape from the above compressed representation.
120 *   If bits 7 and 6 are both set (11), the following 14 bits are an
121 *   offset pointer into the full message to the actual label string from
122 *   another domain name that belongs in this name.  This label pointer
123 *   allows for a further compression of a domain name in a packet.
124 *
125 *   NetBIOS implementations can only use label string pointers in Name
126 *   Service packets.  They cannot be used in Session or Datagram Service
127 *   packets.
128 *
129 *   The other two possible values for bits 7 and 6 (01 and 10) of a label
130 *   length field are reserved for future use by RFC 883[2 (page 32)].
131 *
132 *   Note that the first octet of a compressed name must contain one of
133 *   the following bit patterns.  (An "x" indicates a bit whose value may
134 *   be either 0 or 1.):
135 *
136 *           00100000 -  Netbios name, length must be 32 (decimal)
137 *           11xxxxxx -  Label string pointer
138 *           10xxxxxx -  Reserved
139 *           01xxxxxx -  Reserved
140 */
141
142/*
143 * netbios_first_level_name_encode
144 *
145 * Put test description here.
146 *
147 * Inputs:
148 *	char *	in	-> Name to encode
149 *	char *	out	-> Buffer to encode into.
150 *	int	length	-> # of bytes to encode.
151 *
152 * Returns:
153 *	Nothing
154 */
155int
156netbios_first_level_name_encode(unsigned char *name, unsigned char *scope,
157    unsigned char *out, int max_out)
158{
159	unsigned char	ch, len;
160	unsigned char	 *in;
161	unsigned char	 *lp;
162	unsigned char	 *op = out;
163
164	if (max_out < 0x21)
165		return (-1);
166
167	in = name;
168	*op++ = 0x20;
169	for (len = 0; len < NETBIOS_NAME_SZ; len++) {
170		ch = *in++;
171		*op++ = 'A' + ((ch >> 4) & 0xF);
172		*op++ = 'A' + ((ch) & 0xF);
173	}
174
175	max_out -= 0x21;
176
177	in = scope;
178	len = 0;
179	lp = op++;
180	while (((ch = *in++) != 0) && (max_out-- > 1)) {
181		if (ch == 0) {
182			if ((*lp = len) != 0)
183				*op++ = 0;
184			break;
185		}
186		if (ch == '.') {
187			*lp = len;
188			lp = op++;
189			len = 0;
190		} else {
191			*op++ = ch;
192			len++;
193		}
194	}
195	*lp = len;
196	if (len != 0)
197		*op = 0;
198
199	/*LINTED E_PTRDIFF_OVERFLOW*/
200	return (op - out);
201}
202
203/*
204 * smb_first_level_name_decode
205 *
206 * The null terminated string "in" is the name to decode. The output
207 * is placed in the name_entry structure "name".
208 *
209 * The scope field is a series of length designated labels as described
210 * in the "Domain name representation and compression" section of RFC883.
211 * The two high order two bits of the length field must be zero, the
212 * remaining six bits contain the field length. The total length of the
213 * domain name is restricted to 255 octets but note that the trailing
214 * root label and its dot are not printed. When converting the labels,
215 * the length fields are replaced by dots.
216 *
217 * Returns the number of bytes scanned or -1 to indicate an error.
218 */
219int
220netbios_first_level_name_decode(char *in, char *name, char *scope)
221{
222	unsigned int	length;
223	char		c1, c2;
224	char		*cp;
225	char		*out;
226
227	cp = in;
228
229	if ((length = *cp++) != 0x20) {
230		return (-1);
231	}
232
233	out = name;
234	while (length > 0) {
235		c1 = *cp++;
236		c2 = *cp++;
237
238		if ('A' <= c1 && c1 <= 'P' && 'A' <= c2 && c2 <= 'P') {
239			c1 -= 'A';
240			c2 -= 'A';
241			*out++ = (c1 << 4) | (c2);
242		} else {
243			return (-1);		/* conversion error */
244		}
245		length -= 2;
246	}
247
248	/*
249	 * Don't bother decoding the scope.  Not supported.
250	 */
251	if ((length = *cp++) != 0)
252		return (-1);
253	scope[0] = '\0';
254
255	/*LINTED E_PTRDIFF_OVERFLOW*/
256	return (cp - in);
257}
258
259/*
260 * smb_netbios_name_isvalid
261 *
262 * This function is provided to be used by session service
263 * which runs in kernel in order to hide name_entry definition.
264 *
265 * It returns the decoded name in the provided buffer as 'out'
266 * if it's not null.
267 *
268 * Returns 0 if decode fails, 1 if it succeeds.
269 */
270int
271netbios_name_isvalid(char *in, char *out)
272{
273	char name[NETBIOS_NAME_SZ];
274	char scope[NETBIOS_DOMAIN_NAME_MAX];
275
276	if (netbios_first_level_name_decode(in, name, scope) < 0)
277		return (0);
278
279	if (out)
280		(void) strlcpy(out, name, NETBIOS_NAME_SZ);
281
282	return (1);
283}
284