git.zerfleddert.de Git - proxmark3-svn/blob - client/crypto/asn1dump.c

   1 //-----------------------------------------------------------------------------
   2 // Copyright (C) 2018 Merlok
   3 //
   4 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
   5 // at your option, any later version. See the LICENSE.txt file for the text of
   6 // the license.
   7 //-----------------------------------------------------------------------------
   8 // asn.1 dumping
   9 //-----------------------------------------------------------------------------
  10
  11 #define _POSIX_C_SOURCE 200809L                 // need for strnlen()
  12
  13 #include "asn1dump.h"
  14 #include <ctype.h>
  15 #include <stdlib.h>
  16 #include <unistd.h>
  17 #include <stdio.h>
  18 #include <string.h>
  19 #include <jansson.h>
  20 #include <mbedtls/asn1.h>
  21 #include <mbedtls/oid.h>
  22 #include "emv/emv_tags.h"
  23 #include "emv/dump.h"
  24 #include "emv/emvjson.h"
  25 #include "util.h"
  26 #include "proxmark3.h"
  27
  28 #define PRINT_INDENT(level)     {for (int i = 0; i < (level); i++) fprintf(f, "   ");}
  29
  30 enum asn1_tag_t {
  31         ASN1_TAG_GENERIC,
  32         ASN1_TAG_BOOLEAN,
  33         ASN1_TAG_INTEGER,
  34         ASN1_TAG_STRING,
  35         ASN1_TAG_OCTET_STRING,
  36         ASN1_TAG_UTC_TIME,
  37         ASN1_TAG_STR_TIME,
  38         ASN1_TAG_OBJECT_ID,
  39 };
  40
  41 struct asn1_tag {
  42         tlv_tag_t tag;
  43         char *name;
  44         enum asn1_tag_t type;
  45         const void *data;
  46 };
  47
  48 static const struct asn1_tag asn1_tags[] = {
  49         // internal
  50         { 0x00  , "Unknown ???" },
  51
  52         // ASN.1
  53         { 0x01, "BOOLEAN", ASN1_TAG_BOOLEAN },
  54         { 0x02, "INTEGER", ASN1_TAG_INTEGER },
  55         { 0x03, "BIT STRING" },
  56         { 0x04, "OCTET STRING", ASN1_TAG_OCTET_STRING},
  57         { 0x05, "NULL" },
  58         { 0x06, "OBJECT IDENTIFIER", ASN1_TAG_OBJECT_ID },
  59         { 0x07, "OBJECT DESCRIPTOR" },
  60         { 0x08, "EXTERNAL" },
  61         { 0x09, "REAL" },
  62         { 0x0A, "ENUMERATED" },
  63         { 0x0B, "EMBEDDED_PDV" },
  64         { 0x0C, "UTF8String", ASN1_TAG_STRING },
  65         { 0x10, "SEQUENCE" },
  66         { 0x11, "SET" },
  67         { 0x12, "NumericString", ASN1_TAG_STRING },
  68         { 0x13, "PrintableString", ASN1_TAG_STRING },
  69         { 0x14, "T61String" },
  70         { 0x15, "VideotexString" },
  71         { 0x16, "IA5String" },
  72         { 0x17, "UTCTime", ASN1_TAG_UTC_TIME },
  73         { 0x18, "GeneralizedTime", ASN1_TAG_STR_TIME },
  74         { 0x19, "GraphicString" },
  75         { 0x1A, "VisibleString", ASN1_TAG_STRING },
  76         { 0x1B, "GeneralString", ASN1_TAG_STRING },
  77         { 0x1C, "UniversalString", ASN1_TAG_STRING },
  78         { 0x1E, "BMPString" },
  79         { 0x30, "SEQUENCE" },
  80         { 0x31, "SET" },
  81         { 0xa0, "[0]" },
  82         { 0xa1, "[1]" },
  83         { 0xa2, "[2]" },
  84         { 0xa3, "[3]" },
  85         { 0xa4, "[4]" },
  86         { 0xa5, "[5]" },
  87 };
  88
  89 static int asn1_sort_tag(tlv_tag_t tag) {
  90         return (int)(tag >= 0x100 ? tag : tag << 8);
  91 }
  92
  93 static int asn1_tlv_compare(const void *a, const void *b) {
  94         const struct tlv *tlv = a;
  95         const struct asn1_tag *tag = b;
  96
  97         return asn1_sort_tag(tlv->tag) - (asn1_sort_tag(tag->tag));
  98 }
  99
 100 static const struct asn1_tag *asn1_get_tag(const struct tlv *tlv) {
 101         struct asn1_tag *tag = bsearch(tlv, asn1_tags, sizeof(asn1_tags) / sizeof(asn1_tags[0]),
 102                         sizeof(asn1_tags[0]), asn1_tlv_compare);
 103
 104         return tag ? tag : &asn1_tags[0];
 105 }
 106
 107 static void asn1_tag_dump_str_time(const struct tlv *tlv, const struct asn1_tag *tag, FILE *f, int level, bool longyear, bool *needdump){
 108         int len = tlv->len;
 109         *needdump = false;
 110
 111         int startindx = longyear ? 4 : 2;
 112
 113         if (len > 4) {
 114                 fprintf(f, "\tvalue: '");
 115                 while (true) {
 116                         // year
 117                         if (!longyear)
 118                                 fprintf(f, "20");
 119                         fwrite(tlv->value, 1, longyear ? 4 : 2, f);
 120                         fprintf(f, "-");
 121                         if (len < startindx + 2)
 122                                 break;
 123                         // month
 124                         fwrite(&tlv->value[startindx], 1, 2, f);
 125                         fprintf(f, "-");
 126                         if (len < startindx + 4)
 127                                 break;
 128                         // day
 129                         fwrite(&tlv->value[startindx + 2], 1, 2, f);
 130                         fprintf(f, " ");
 131                         if (len < startindx + 6)
 132                                 break;
 133                         // hour
 134                         fwrite(&tlv->value[startindx + 4], 1, 2, f);
 135                         fprintf(f, ":");
 136                         if (len < startindx + 8)
 137                                 break;
 138                         // min
 139                         fwrite(&tlv->value[startindx + 6], 1, 2, f);
 140                         fprintf(f, ":");
 141                         if (len < startindx + 10)
 142                                 break;
 143                         // sec
 144                         fwrite(&tlv->value[startindx + 8], 1, 2, f);
 145                         if (len < startindx + 11)
 146                                 break;
 147                         // time zone
 148                         fprintf(f, " zone: %.*s", len - 10 - (longyear ? 4 : 2), &tlv->value[startindx + 10]);
 149
 150                         break;
 151                 }
 152                 fprintf(f, "'\n");
 153         } else {
 154                 fprintf(f, "\n");
 155                 *needdump = true;
 156         }
 157 }
 158
 159 static void asn1_tag_dump_string(const struct tlv *tlv, const struct asn1_tag *tag, FILE *f, int level){
 160         fprintf(f, "\tvalue: '");
 161         fwrite(tlv->value, 1, tlv->len, f);
 162         fprintf(f, "'\n");
 163 }
 164
 165 static void asn1_tag_dump_octet_string(const struct tlv *tlv, const struct asn1_tag *tag, FILE *f, int level, bool *needdump){
 166         *needdump = false;
 167         for (int i = 0; i < tlv->len; i++)
 168                 if (!isspace(tlv->value[i]) && !isprint(tlv->value[i])){
 169                         *needdump = true;
 170                         break;
 171                 }
 172
 173         if (*needdump) {
 174                 fprintf(f, "'\n");
 175         } else {
 176                 fprintf(f, "\t\t");
 177                 asn1_tag_dump_string(tlv, tag, f, level);
 178         }
 179 }
 180
 181 static unsigned long asn1_value_integer(const struct tlv *tlv, unsigned start, unsigned end) {
 182         unsigned long ret = 0;
 183         int i;
 184
 185         if (end > tlv->len * 2)
 186                 return ret;
 187         if (start >= end)
 188                 return ret;
 189
 190         if (start & 1) {
 191                 ret += tlv->value[start/2] & 0xf;
 192                 i = start + 1;
 193         } else
 194                 i = start;
 195
 196         for (; i < end - 1; i += 2) {
 197                 ret *= 10;
 198                 ret += tlv->value[i/2] >> 4;
 199                 ret *= 10;
 200                 ret += tlv->value[i/2] & 0xf;
 201         }
 202
 203         if (end & 1) {
 204                 ret *= 10;
 205                 ret += tlv->value[end/2] >> 4;
 206         }
 207
 208         return ret;
 209 }
 210
 211 static void asn1_tag_dump_boolean(const struct tlv *tlv, const struct asn1_tag *tag, FILE *f, int level) {
 212         PRINT_INDENT(level);
 213         if (tlv->len > 0) {
 214                 fprintf(f, "\tvalue: %s\n", tlv->value[0]?"true":"false");
 215         } else {
 216                 fprintf(f, "n/a\n");
 217         }
 218 }
 219
 220 static void asn1_tag_dump_integer(const struct tlv *tlv, const struct asn1_tag *tag, FILE *f, int level) {
 221         PRINT_INDENT(level);
 222         if (tlv->len == 4) {
 223                 int32_t val = 0;
 224                 for (int i = 0; i < tlv->len; i++)
 225                         val = (val << 8) + tlv->value[i];
 226                 fprintf(f, "\tvalue4b: %d\n", val);
 227                 return;
 228         }
 229         fprintf(f, "\tvalue: %lu\n", asn1_value_integer(tlv, 0, tlv->len * 2));
 230 }
 231
 232 static char *asn1_oid_description(const char *oid, bool with_group_desc) {
 233         json_error_t error;
 234         json_t *root = NULL;
 235         char fname[300] = {0};
 236         static char res[300];
 237         memset(res, 0x00, sizeof(res));
 238
 239         strcpy(fname, get_my_executable_directory());
 240         strcat(fname, "crypto/oids.json");
 241         if (access(fname, F_OK) < 0) {
 242                 strcpy(fname, get_my_executable_directory());
 243                 strcat(fname, "oids.json");
 244                 if (access(fname, F_OK) < 0) {
 245                         goto error; // file not found
 246                 }
 247         }
 248
 249         // load `oids.json`
 250         root = json_load_file(fname, 0, &error);
 251
 252         if (!root || !json_is_object(root)) {
 253                 goto error;
 254         }
 255
 256         json_t *elm = json_object_get(root, oid);
 257         if (!elm) {
 258                 goto error;
 259         }
 260
 261         if (JsonLoadStr(elm, "$.d", res))
 262                 goto error;
 263
 264         char strext[300] = {0};
 265         if (!JsonLoadStr(elm, "$.c", strext)) {
 266                 strcat(res, " (");
 267                 strcat(res, strext);
 268                 strcat(res, ")");
 269         }
 270
 271         json_decref(root);
 272         return res;
 273
 274 error:
 275         if (root)
 276                 json_decref(root);
 277         return NULL;
 278 }
 279
 280 static void asn1_tag_dump_object_id(const struct tlv *tlv, const struct asn1_tag *tag, FILE *f, int level) {
 281         PRINT_INDENT(level);
 282         mbedtls_asn1_buf asn1_buf;
 283         asn1_buf.len = tlv->len;
 284         asn1_buf.p = (uint8_t *)tlv->value;
 285         char pstr[300];
 286         mbedtls_oid_get_numeric_string(pstr, sizeof(pstr), &asn1_buf);
 287         fprintf(f, " %s", pstr);
 288
 289         char *jsondesc = asn1_oid_description(pstr, true);
 290         if (jsondesc) {
 291                 fprintf(f, " -  %s", jsondesc);
 292         } else {
 293                 const char *ppstr;
 294                 mbedtls_oid_get_attr_short_name(&asn1_buf, &ppstr);
 295                 if (ppstr && strnlen(ppstr, 1)) {
 296                         fprintf(f, " (%s)\n", ppstr);
 297                         return;
 298                 }
 299                 mbedtls_oid_get_sig_alg_desc(&asn1_buf, &ppstr);
 300                 if (ppstr && strnlen(ppstr, 1)) {
 301                         fprintf(f, " (%s)\n", ppstr);
 302                         return;
 303                 }
 304                 mbedtls_oid_get_extended_key_usage(&asn1_buf, &ppstr);
 305                 if (ppstr && strnlen(ppstr, 1)) {
 306                         fprintf(f, " (%s)\n", ppstr);
 307                         return;
 308                 }
 309         }
 310         fprintf(f, "\n");
 311 }
 312
 313 bool asn1_tag_dump(const struct tlv *tlv, FILE *f, int level, bool *candump) {
 314         if (!tlv) {
 315                 fprintf(f, "NULL\n");
 316                 return false;
 317         }
 318
 319         const struct asn1_tag *tag = asn1_get_tag(tlv);
 320
 321         PRINT_INDENT(level);
 322         fprintf(f, "--%2hx[%02zx] '%s':", tlv->tag, tlv->len, tag->name);
 323
 324         switch (tag->type) {
 325         case ASN1_TAG_GENERIC:
 326                 fprintf(f, "\n");
 327                 break;
 328         case ASN1_TAG_STRING:
 329                 asn1_tag_dump_string(tlv, tag, f, level);
 330                 *candump = false;
 331                 break;
 332         case ASN1_TAG_OCTET_STRING:
 333                 asn1_tag_dump_octet_string(tlv, tag, f, level, candump);
 334                 break;
 335         case ASN1_TAG_BOOLEAN:
 336                 asn1_tag_dump_boolean(tlv, tag, f, level);
 337                 *candump = false;
 338                 break;
 339         case ASN1_TAG_INTEGER:
 340                 asn1_tag_dump_integer(tlv, tag, f, level);
 341                 *candump = false;
 342                 break;
 343         case ASN1_TAG_UTC_TIME:
 344                 asn1_tag_dump_str_time(tlv, tag, f, level, false, candump);
 345                 break;
 346         case ASN1_TAG_STR_TIME:
 347                 asn1_tag_dump_str_time(tlv, tag, f, level, true, candump);
 348                 break;
 349         case ASN1_TAG_OBJECT_ID:
 350                 asn1_tag_dump_object_id(tlv, tag, f, level);
 351                 *candump = false;
 352                 break;
 353         };
 354
 355         return true;
 356 }