usr/src/common/smbsrv/smb_netbios_util.c

   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)
  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  */
 155 int
 156 netbios_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  */
 219 int
 220 netbios_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  */
 270 int
 271 netbios_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 }