epan/dissectors/packet-banana.c

   1 /* packet-bananna.c
   2  * Routines for the Twisted Banana serialization protocol dissection
   3  * Copyright 2009, Gerald Combs <gerald@wireshark.org>
   4  *
   5  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 1998 Gerald Combs
   8  *
   9  * SPDX-License-Identifier: GPL-2.0-or-later
  10  */
  11
  12 /*
  13  * Based on "Banana Protocol Specifications"
  14  * https://twisted.org/documents/16.1.1/core/specifications/banana.html
  15  */
  16
  17 #include "config.h"
  18
  19 #include <epan/packet.h>
  20 #include <epan/expert.h>
  21
  22 void proto_register_banana(void);
  23 void proto_reg_handoff_banana(void);
  24
  25 /* Initialize the protocol and registered fields */
  26 static int proto_banana;
  27 static int hf_banana_list;
  28 static int hf_banana_int;
  29 static int hf_banana_string;
  30 static int hf_banana_neg_int;
  31 static int hf_banana_float;
  32 static int hf_banana_lg_int;
  33 static int hf_banana_lg_neg_int;
  34 static int hf_banana_pb;
  35
  36 /* Initialize the subtree pointers */
  37 static int ett_banana;
  38 static int ett_list;
  39
  40 static expert_field ei_banana_unknown_type;
  41 static expert_field ei_banana_too_many_value_bytes;
  42 static expert_field ei_banana_length_too_long;
  43 static expert_field ei_banana_value_too_large;
  44 static expert_field ei_banana_pb_error;
  45
  46 static dissector_handle_t banana_handle;
  47
  48 #define BE_LIST         0x80
  49 #define BE_INT          0x81
  50 #define BE_STRING       0x82
  51 #define BE_NEG_INT      0x83
  52 #define BE_FLOAT        0x84
  53 #define BE_LG_INT       0x85
  54 #define BE_LG_NEG_INT   0x86
  55 #define BE_PB           0x87
  56
  57 #define is_element(b) (b >= BE_LIST && b <= BE_PB)
  58
  59 static const value_string type_vals[] = {
  60     { BE_LIST,          "List" },
  61     { BE_INT,           "Integer" },
  62     { BE_STRING,        "String" },
  63     { BE_NEG_INT,       "Negative Integer" },
  64     { BE_FLOAT,         "Float" },
  65     { BE_LG_INT,        "Large Integer" },
  66     { BE_LG_NEG_INT,    "Large Negative Integer" },
  67     { BE_PB,            "pb Profile"},
  68     { 0, NULL }
  69 };
  70
  71 static const value_string pb_vals[] = {
  72     { 0x01, "None" },
  73     { 0x02, "class" },
  74     { 0x03, "dereference" },
  75     { 0x04, "reference" },
  76     { 0x05, "dictionary" },
  77     { 0x06, "function" },
  78     { 0x07, "instance" },
  79     { 0x08, "list" },
  80     { 0x09, "module" },
  81     { 0x0a, "persistent" },
  82     { 0x0b, "tuple" },
  83     { 0x0c, "unpersistable" },
  84     { 0x0d, "copy" },
  85     { 0x0e, "cache" },
  86     { 0x0f, "cached" },
  87     { 0x10, "remote" },
  88     { 0x11, "local" },
  89     { 0x12, "lcache" },
  90     { 0x13, "version" },
  91     { 0x14, "login" },
  92     { 0x15, "password" },
  93     { 0x16, "challenge" },
  94     { 0x17, "logged_in" },
  95     { 0x18, "not_logged_in" },
  96     { 0x19, "cachemessage" },
  97     { 0x1a, "message" },
  98     { 0x1b, "answer" },
  99     { 0x1c, "error" },
 100     { 0x1d, "decref" },
 101     { 0x1e, "decache" },
 102     { 0x1f, "uncache" },
 103     { 0,    NULL }
 104 };
 105
 106 #define MAX_ELEMENT_VAL 2147483647 /* Max TE value */
 107 #define MAX_ELEMENT_INT_LEN 4
 108 #define MAX_ELEMENT_VAL_LEN 8
 109
 110 /* Dissect the packets */
 111
 112 static int
 113 // NOLINTNEXTLINE(misc-no-recursion)
 114 dissect_banana_element(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int offset) {
 115     proto_item *ti;
 116     proto_tree *list_tree;
 117     uint8_t byte = 0;
 118     int64_t val = 0;
 119     int val_len = 0;
 120     int start_offset = offset;
 121     int old_offset;
 122     int i;
 123
 124     /* Accumulate our value/length 'til we hit a valid type */
 125     while (tvb_reported_length_remaining(tvb, offset) > 0) {
 126         byte = tvb_get_uint8(tvb, offset);
 127         offset++;
 128
 129         if (byte & 0x80) {
 130             if (is_element(byte)) {
 131                 break;
 132             } else {
 133                 expert_add_info_format(pinfo, NULL, &ei_banana_unknown_type, "Unknown type %u", byte);
 134             }
 135         } else {
 136             val_len++;
 137             if (val_len > MAX_ELEMENT_VAL_LEN) {
 138                 expert_add_info(pinfo, NULL, &ei_banana_too_many_value_bytes);
 139             }
 140             val += byte + (val << 7);
 141         }
 142     }
 143
 144     /* Type */
 145     switch (byte) {
 146         case BE_LIST:
 147             if (val > MAX_ELEMENT_VAL) {
 148                 expert_add_info_format(pinfo, NULL, &ei_banana_length_too_long, "List length %" PRId64 " longer than we can handle", val);
 149             }
 150             ti = proto_tree_add_uint_format_value(tree, hf_banana_list, tvb, start_offset, offset - start_offset - 1, (uint32_t) val, "(%d items)", (int) val);
 151             list_tree = proto_item_add_subtree(ti, ett_list);
 152             for (i = 0; i < val; i++) {
 153                 old_offset = offset;
 154                 increment_dissection_depth(pinfo);
 155                 offset += dissect_banana_element(tvb, pinfo, list_tree, offset);
 156                 decrement_dissection_depth(pinfo);
 157                 if (offset <= old_offset) {
 158                     return offset - start_offset;
 159                 }
 160             }
 161             break;
 162         case BE_INT:
 163             if (val > MAX_ELEMENT_VAL) {
 164                 expert_add_info_format(pinfo, NULL, &ei_banana_value_too_large, "Integer value %" PRId64 " too large", val);
 165             }
 166             proto_tree_add_uint(tree, hf_banana_int, tvb, start_offset, offset - start_offset, (uint32_t) val);
 167             break;
 168         case BE_STRING:
 169             if (val > MAX_ELEMENT_VAL) {
 170                 expert_add_info_format(pinfo, NULL, &ei_banana_length_too_long, "String length %" PRId64 " longer than we can handle", val);
 171             }
 172             proto_tree_add_item(tree, hf_banana_string, tvb, offset, (uint32_t) val, ENC_ASCII);
 173             offset += (int) val;
 174             break;
 175         case BE_NEG_INT:
 176             if (val > MAX_ELEMENT_VAL) {
 177                 expert_add_info_format(pinfo, NULL, &ei_banana_value_too_large, "Integer value -%" PRId64 " too large", val);
 178             }
 179             proto_tree_add_int(tree, hf_banana_neg_int, tvb, start_offset, offset - start_offset, (int32_t) val * -1);
 180             break;
 181         case BE_FLOAT:
 182             proto_tree_add_item(tree, hf_banana_float, tvb, offset, 8, ENC_BIG_ENDIAN);
 183             offset += 8;
 184             break;
 185         case BE_LG_INT:
 186             proto_tree_add_item(tree, hf_banana_lg_int, tvb, start_offset, offset - start_offset, ENC_NA);
 187             break;
 188         case BE_LG_NEG_INT:
 189             proto_tree_add_item(tree, hf_banana_lg_neg_int, tvb, start_offset, offset - start_offset, ENC_NA);
 190             break;
 191         case BE_PB:
 192             if (val_len > 1) {
 193                 expert_add_info(pinfo, NULL, &ei_banana_pb_error);
 194             }
 195             /*
 196              * The spec says the pb dictionary value comes after the tag.
 197              * In real-world captures it comes before.
 198              */
 199             proto_tree_add_item(tree, hf_banana_pb, tvb, offset - 2, 1, ENC_BIG_ENDIAN);
 200             break;
 201         default:
 202             return 0;
 203     }
 204     return offset - start_offset;
 205 }
 206
 207 static int
 208 dissect_banana(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) {
 209     uint8_t byte = 0;
 210     int offset = 0, old_offset;
 211     proto_item *ti;
 212     proto_tree *banana_tree;
 213
 214     /* Check that there's enough data */
 215     if (tvb_reported_length(tvb) < 2)
 216         return 0;
 217
 218     /* Fill in our protocol and info columns */
 219     col_set_str(pinfo->cinfo, COL_PROTOCOL, "Banana");
 220
 221     while (tvb_reported_length_remaining(tvb, offset) > 0 && offset < MAX_ELEMENT_VAL_LEN) {
 222         byte = tvb_get_uint8(tvb, offset);
 223         if (is_element(byte))
 224             break;
 225         offset++;
 226     }
 227     col_add_fstr(pinfo->cinfo, COL_INFO, "First element: %s",
 228         val_to_str(byte, type_vals, "Unknown type: %u"));
 229
 230     /* Create display subtree for the protocol */
 231     ti = proto_tree_add_item(tree, proto_banana, tvb, 0, -1, ENC_NA);
 232     banana_tree = proto_item_add_subtree(ti, ett_banana);
 233
 234     offset = 0;
 235     old_offset = -1;
 236     while (offset > old_offset) {
 237         old_offset = offset;
 238         offset += dissect_banana_element(tvb, pinfo, banana_tree, offset);
 239     }
 240
 241     /* Return the amount of data this dissector was able to dissect */
 242     return tvb_reported_length(tvb);
 243 }
 244
 245 /* Register the protocol with Wireshark */
 246
 247 void
 248 proto_register_banana(void)
 249 {
 250     static hf_register_info hf[] = {
 251         { &hf_banana_list,
 252             { "List Length", "banana.list",
 253                 FT_UINT32, BASE_DEC, NULL, 0,
 254                 "Banana list", HFILL }
 255         },
 256         { &hf_banana_int,
 257             { "Integer", "banana.int",
 258                 FT_UINT32, BASE_DEC, NULL, 0,
 259                 "Banana integer", HFILL }
 260         },
 261         { &hf_banana_string,
 262             { "String", "banana.string",
 263                 FT_STRING, BASE_NONE, NULL, 0,
 264                 "Banana string", HFILL }
 265         },
 266         { &hf_banana_neg_int,
 267             { "Negative Integer", "banana.neg_int",
 268                 FT_INT32, BASE_DEC, NULL, 0,
 269                 "Banana negative integer", HFILL }
 270         },
 271         { &hf_banana_float,
 272             { "Float", "banana.float",
 273                 FT_DOUBLE, BASE_NONE, NULL, 0,
 274                 "Banana float", HFILL }
 275         },
 276         { &hf_banana_lg_int,
 277             { "Float", "banana.lg_int",
 278                 FT_BYTES, BASE_NONE, NULL, 0,
 279                 "Banana large integer", HFILL }
 280         },
 281         { &hf_banana_lg_neg_int,
 282             { "Float", "banana.lg_neg_int",
 283                 FT_BYTES, BASE_NONE, NULL, 0,
 284                 "Banana large negative integer", HFILL }
 285         },
 286         { &hf_banana_pb,
 287             { "pb Profile Value", "banana.pb",
 288                 FT_UINT8, BASE_HEX, VALS(pb_vals), 0,
 289                 "Banana Perspective Broker Profile Value", HFILL }
 290         }
 291     };
 292
 293     expert_module_t* expert_banana;
 294
 295     /* Setup protocol subtree array */
 296     static int *ett[] = {
 297         &ett_banana,
 298         &ett_list
 299     };
 300
 301     static ei_register_info ei[] = {
 302         { &ei_banana_unknown_type, { "banana.unknown_type", PI_UNDECODED, PI_ERROR, "Unknown type", EXPFILL }},
 303         { &ei_banana_too_many_value_bytes, { "banana.too_many_value_bytes", PI_UNDECODED, PI_ERROR, "Too many value/length bytes", EXPFILL }},
 304         { &ei_banana_length_too_long, { "banana.length_too_long", PI_UNDECODED, PI_ERROR, "Length too long", EXPFILL }},
 305         { &ei_banana_value_too_large, { "banana.value_too_large", PI_MALFORMED, PI_ERROR, "Value too large", EXPFILL }},
 306         { &ei_banana_pb_error, { "banana.pb_error", PI_MALFORMED, PI_ERROR, "More than 1 byte before pb", EXPFILL }},
 307     };
 308
 309     /* Register the protocol name and description */
 310     proto_banana = proto_register_protocol("Twisted Banana", "Banana", "banana");
 311
 312     /* Required function calls to register the header fields and subtrees used */
 313     proto_register_field_array(proto_banana, hf, array_length(hf));
 314     proto_register_subtree_array(ett, array_length(ett));
 315     expert_banana = expert_register_protocol(proto_banana);
 316     expert_register_field_array(expert_banana, ei, array_length(ei));
 317
 318     banana_handle = register_dissector("banana", dissect_banana, proto_banana);
 319 }
 320
 321 void
 322 proto_reg_handoff_banana(void)
 323 {
 324     dissector_add_uint_range_with_preference("tcp.port", "", banana_handle);
 325 }
 326
 327 /*
 328  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 329  *
 330  * Local variables:
 331  * c-basic-offset: 4
 332  * tab-width: 8
 333  * indent-tabs-mode: nil
 334  * End:
 335  *
 336  * ex: set shiftwidth=4 tabstop=8 expandtab:
 337  * :indentSize=4:tabSize=8:noTabs=true:
 338  */
 339
 340