package/iptables/patches/002-layer7_2.22.patch

   1 --- /dev/null
   2 +++ b/extensions/libxt_layer7.c
   3 @@ -0,0 +1,368 @@
   4 +/*
   5 +   Shared library add-on to iptables for layer 7 matching support.
   6 +
   7 +   By Matthew Strait <quadong@users.sf.net>, Oct 2003-Aug 2008.
   8 +
   9 +   http://l7-filter.sf.net
  10 +
  11 +   This program is free software; you can redistribute it and/or
  12 +   modify it under the terms of the GNU General Public License
  13 +   as published by the Free Software Foundation; either version
  14 +   2 of the License, or (at your option) any later version.
  15 +   http://www.gnu.org/licenses/gpl.txt
  16 +*/
  17 +
  18 +#define _GNU_SOURCE
  19 +#include <stdio.h>
  20 +#include <netdb.h>
  21 +#include <string.h>
  22 +#include <stdlib.h>
  23 +#include <getopt.h>
  24 +#include <ctype.h>
  25 +#include <dirent.h>
  26 +
  27 +#include <xtables.h>
  28 +#include <linux/netfilter/xt_layer7.h>
  29 +
  30 +#define MAX_FN_LEN 256
  31 +
  32 +static char l7dir[MAX_FN_LEN] = "\0";
  33 +
  34 +/* Function which prints out usage message. */
  35 +static void help(void)
  36 +{
  37 +       printf(
  38 +       "layer7 match options:\n"
  39 +       "    --l7dir <directory> : Look for patterns here instead of /etc/l7-protocols/\n"
  40 +       "                          (--l7dir must be specified before --l7proto if used)\n"
  41 +       "[!] --l7proto <name>: Match named protocol using /etc/l7-protocols/.../name.pat\n");
  42 +}
  43 +
  44 +static const struct option opts[] = {
  45 +       { .name = "l7proto", .has_arg = 1, .val = 'p' },
  46 +       { .name = "l7dir",   .has_arg = 1, .val = 'd' },
  47 +       { .name = NULL }
  48 +};
  49 +
  50 +/* reads filename, puts protocol info into layer7_protocol_info, number of protocols to numprotos */
  51 +static int parse_protocol_file(char * filename, const char * protoname, struct xt_layer7_info *info)
  52 +{
  53 +       FILE * f;
  54 +       char * line = NULL;
  55 +       size_t len = 0;
  56 +
  57 +       enum { protocol, pattern, done } datatype = protocol;
  58 +
  59 +       f = fopen(filename, "r");
  60 +
  61 +       if(!f)
  62 +               return 0;
  63 +
  64 +       while(getline(&line, &len, f) != -1)
  65 +       {
  66 +               if(strlen(line) < 2 || line[0] == '#')
  67 +                       continue;
  68 +
  69 +               /* strip the pesky newline... */
  70 +               if(line[strlen(line) - 1] == '\n')
  71 +                       line[strlen(line) - 1] = '\0';
  72 +
  73 +               if(datatype == protocol)
  74 +               {
  75 +                       /* Ignore everything on the line beginning with the
  76 +                       first space or tab . For instance, this allows the
  77 +                       protocol line in http.pat to be "http " (or
  78 +                       "http I am so cool") instead of just "http". */
  79 +                       if(strchr(line, ' ')){
  80 +                               char * space = strchr(line, ' ');
  81 +                               space[0] = '\0';
  82 +                       }
  83 +                       if(strchr(line, '\t')){
  84 +                               char * space = strchr(line, '\t');
  85 +                               space[0] = '\0';
  86 +                       }
  87 +
  88 +                       /* sanity check.  First non-comment non-blank
  89 +                       line must be the same as the file name. */
  90 +                       if(strcmp(line, protoname))
  91 +                               xtables_error(OTHER_PROBLEM,
  92 +                                       "Protocol name (%s) doesn't match file name (%s).  Bailing out\n",
  93 +                                       line, filename);
  94 +
  95 +                       if(strlen(line) >= MAX_PROTOCOL_LEN)
  96 +                                xtables_error(PARAMETER_PROBLEM,
  97 +                                       "Protocol name in %s too long!", filename);
  98 +                       strncpy(info->protocol, line, MAX_PROTOCOL_LEN);
  99 +
 100 +                       datatype = pattern;
 101 +               }
 102 +               else if(datatype == pattern)
 103 +               {
 104 +                       if(strlen(line) >= MAX_PATTERN_LEN)
 105 +                                xtables_error(PARAMETER_PROBLEM, "Pattern in %s too long!", filename);
 106 +                       strncpy(info->pattern, line, MAX_PATTERN_LEN);
 107 +
 108 +                       datatype = done;
 109 +                       break;
 110 +               }
 111 +               else
 112 +                       xtables_error(OTHER_PROBLEM, "Internal error");
 113 +       }
 114 +
 115 +       if(datatype != done)
 116 +               xtables_error(OTHER_PROBLEM, "Failed to get all needed data from %s", filename);
 117 +
 118 +       if(line) free(line);
 119 +       fclose(f);
 120 +
 121 +       return 1;
 122 +}
 123 +
 124 +static int hex2dec(char c)
 125 +{
 126 +        switch (c)
 127 +        {
 128 +                case '0' ... '9':
 129 +                        return c - '0';
 130 +                case 'a' ... 'f':
 131 +                        return c - 'a' + 10;
 132 +                case 'A' ... 'F':
 133 +                        return c - 'A' + 10;
 134 +                default:
 135 +                        xtables_error(OTHER_PROBLEM, "hex2dec: bad value!\n");
 136 +                        return 0;
 137 +        }
 138 +}
 139 +
 140 +/* takes a string with \xHH escapes and returns one with the characters
 141 +they stand for */
 142 +static char * pre_process(char * s)
 143 +{
 144 +       char * result = malloc(strlen(s) + 1);
 145 +       int sindex = 0, rrindex = 0;
 146 +        while( sindex < strlen(s) )
 147 +        {
 148 +            if( sindex + 3 < strlen(s) &&
 149 +                s[sindex] == '\\' && s[sindex+1] == 'x' &&
 150 +                isxdigit(s[sindex + 2]) && isxdigit(s[sindex + 3]) )
 151 +                {
 152 +                        /* carefully remember to call tolower here... */
 153 +                        result[rrindex] = tolower( hex2dec(s[sindex + 2])*16 +
 154 +                                                  hex2dec(s[sindex + 3] ) );
 155 +
 156 +                       switch ( result[rrindex] )
 157 +                       {
 158 +                       case 0x24:
 159 +                       case 0x28:
 160 +                       case 0x29:
 161 +                       case 0x2a:
 162 +                       case 0x2b:
 163 +                       case 0x2e:
 164 +                       case 0x3f:
 165 +                       case 0x5b:
 166 +                       case 0x5c:
 167 +                       case 0x5d:
 168 +                       case 0x5e:
 169 +                       case 0x7c:
 170 +                               fprintf(stderr,
 171 +                                       "Warning: layer7 regexp contains a control character, %c, in hex (\\x%c%c).\n"
 172 +                                       "I recommend that you write this as %c or \\%c, depending on what you meant.\n",
 173 +                                       result[rrindex], s[sindex + 2], s[sindex + 3], result[rrindex], result[rrindex]);
 174 +                               break;
 175 +                       case 0x00:
 176 +                               fprintf(stderr,
 177 +                                       "Warning: null (\\x00) in layer7 regexp.  A null terminates the regexp string!\n");
 178 +                               break;
 179 +                       default:
 180 +                               break;
 181 +                       }
 182 +
 183 +
 184 +                        sindex += 3; /* 4 total */
 185 +                }
 186 +                else
 187 +                        result[rrindex] = tolower(s[sindex]);
 188 +
 189 +               sindex++;
 190 +               rrindex++;
 191 +        }
 192 +       result[rrindex] = '\0';
 193 +
 194 +       return result;
 195 +}
 196 +
 197 +#define MAX_SUBDIRS 128
 198 +static char ** readl7dir(char * dirname)
 199 +{
 200 +        DIR             * scratchdir;
 201 +        struct dirent   ** namelist;
 202 +       char ** subdirs = malloc(MAX_SUBDIRS * sizeof(char *));
 203 +
 204 +        int n, d = 1;
 205 +       subdirs[0] = "";
 206 +
 207 +        n = scandir(dirname, &namelist, 0, alphasort);
 208 +
 209 +       if (n < 0)
 210 +       {
 211 +            perror("scandir");
 212 +           xtables_error(OTHER_PROBLEM, "Couldn't open %s\n", dirname);
 213 +       }
 214 +        else
 215 +       {
 216 +               while(n--)
 217 +               {
 218 +                       char fulldirname[MAX_FN_LEN];
 219 +
 220 +                       snprintf(fulldirname, MAX_FN_LEN, "%s/%s", dirname, namelist[n]->d_name);
 221 +
 222 +                       if((scratchdir = opendir(fulldirname)) != NULL)
 223 +                       {
 224 +                               closedir(scratchdir);
 225 +
 226 +                               if(!strcmp(namelist[n]->d_name, ".") ||
 227 +                                  !strcmp(namelist[n]->d_name, ".."))
 228 +                                       /* do nothing */ ;
 229 +                               else
 230 +                               {
 231 +                                       subdirs[d] = malloc(strlen(namelist[n]->d_name) + 1);
 232 +                                       strcpy(subdirs[d], namelist[n]->d_name);
 233 +                                       d++;
 234 +                                       if(d >= MAX_SUBDIRS - 1)
 235 +                                       {
 236 +                                               fprintf(stderr,
 237 +                                                 "Too many subdirectories, skipping the rest!\n");
 238 +                                               break;
 239 +                                       }
 240 +                               }
 241 +                       }
 242 +                       free(namelist[n]);
 243 +               }
 244 +               free(namelist);
 245 +        }
 246 +
 247 +       subdirs[d] = NULL;
 248 +
 249 +       return subdirs;
 250 +}
 251 +
 252 +static void parse_layer7_protocol(const char *s, struct xt_layer7_info *info)
 253 +{
 254 +       char filename[MAX_FN_LEN];
 255 +       char * dir = NULL;
 256 +       char ** subdirs;
 257 +       int n = 0, done = 0;
 258 +
 259 +       if(strlen(l7dir) > 0) dir = l7dir;
 260 +       else                  dir = "/etc/l7-protocols";
 261 +
 262 +       subdirs = readl7dir(dir);
 263 +
 264 +       while(subdirs[n] != NULL)
 265 +       {
 266 +               int c = snprintf(filename, MAX_FN_LEN, "%s/%s/%s.pat", dir, subdirs[n], s);
 267 +
 268 +               if(c > MAX_FN_LEN)
 269 +                       xtables_error(OTHER_PROBLEM,
 270 +                               "Filename beginning with %s is too long!\n", filename);
 271 +
 272 +               /* read in the pattern from the file */
 273 +               if(parse_protocol_file(filename, s, info)){
 274 +                       done = 1;
 275 +                       break;
 276 +               }
 277 +
 278 +               n++;
 279 +       }
 280 +
 281 +       if(!done)
 282 +               xtables_error(OTHER_PROBLEM,
 283 +                       "Couldn't find a pattern definition file for %s.\n", s);
 284 +
 285 +       /* process \xHH escapes and tolower everything. (our regex lib has no
 286 +       case insensitivity option.) */
 287 +       strncpy(info->pattern, pre_process(info->pattern), MAX_PATTERN_LEN);
 288 +}
 289 +
 290 +/* Function which parses command options; returns true if it ate an option */
 291 +static int parse(int c, char **argv, int invert, unsigned int *flags,
 292 +      const void *entry, struct xt_entry_match **match)
 293 +{
 294 +       struct xt_layer7_info *layer7info =
 295 +               (struct xt_layer7_info *)(*match)->data;
 296 +
 297 +       switch (c) {
 298 +       case 'p':
 299 +               parse_layer7_protocol(argv[optind-1], layer7info);
 300 +               if (invert)
 301 +                       layer7info->invert = true;
 302 +               *flags = 1;
 303 +               break;
 304 +
 305 +       case 'd':
 306 +               if(strlen(argv[optind-1]) >= MAX_FN_LEN)
 307 +                       xtables_error(PARAMETER_PROBLEM, "directory name too long\n");
 308 +
 309 +               strncpy(l7dir, argv[optind-1], MAX_FN_LEN);
 310 +
 311 +               *flags = 1;
 312 +               break;
 313 +
 314 +       default:
 315 +               return 0;
 316 +       }
 317 +
 318 +       return 1;
 319 +}
 320 +
 321 +/* Final check; must have specified --l7proto */
 322 +static void final_check(unsigned int flags)
 323 +{
 324 +       if (!flags)
 325 +               xtables_error(PARAMETER_PROBLEM,
 326 +                          "LAYER7 match: You must specify `--l7proto'");
 327 +}
 328 +
 329 +static void print_protocol(char s[], int invert, int numeric)
 330 +{
 331 +       fputs("l7proto ", stdout);
 332 +       if (invert) fputc('!', stdout);
 333 +       printf("%s ", s);
 334 +}
 335 +
 336 +/* Prints out the matchinfo. */
 337 +static void print(const void *ip,
 338 +      const struct xt_entry_match *match,
 339 +      int numeric)
 340 +{
 341 +       printf("LAYER7 ");
 342 +       print_protocol(((struct xt_layer7_info *)match->data)->protocol,
 343 +                 ((struct xt_layer7_info *)match->data)->invert, numeric);
 344 +}
 345 +/* Saves the union ipt_matchinfo in parsable form to stdout. */
 346 +static void save(const void *ip, const struct xt_entry_match *match)
 347 +{
 348 +        const struct xt_layer7_info *info =
 349 +            (const struct xt_layer7_info*) match->data;
 350 +
 351 +        printf("--l7proto %s%s ", (info->invert)? "! ":"", info->protocol);
 352 +}
 353 +
 354 +static struct xtables_match layer7 = {
 355 +    .family        = AF_INET,
 356 +    .name          = "layer7",
 357 +    .version       = XTABLES_VERSION,
 358 +    .size          = XT_ALIGN(sizeof(struct xt_layer7_info)),
 359 +    .userspacesize = XT_ALIGN(sizeof(struct xt_layer7_info)),
 360 +    .help          = &help,
 361 +    .parse         = &parse,
 362 +    .final_check   = &final_check,
 363 +    .print         = &print,
 364 +    .save          = &save,
 365 +    .extra_opts    = opts
 366 +};
 367 +
 368 +void _init(void)
 369 +{
 370 +       xtables_register_match(&layer7);
 371 +}