mdw@git.distorted.org.uk Git - yaid/blob - policy.c

   1 /* -*-c-*-
   2  *
   3  * Policy parsing and implementation
   4  *
   5  * (c) 2012 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Yet Another Ident Daemon (YAID).
  11  *
  12  * YAID is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * YAID is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with YAID; if not, write to the Free Software Foundation,
  24  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  25  */
  26
  27 /*----- Header files ------------------------------------------------------*/
  28
  29 #include "yaid.h"
  30
  31 /*----- Main code ---------------------------------------------------------*/
  32
  33 /* syntax: addrpat portpat addrpar portpat policy
  34  *
  35  * local address/port first, then remote
  36  * addrpat ::= addr [/ len]
  37  * portpat ::= num | num - num | *
  38  * policy ::= user policy* | token | name | deny | hide |
  39  */
  40
  41 void init_policy(struct policy *p) { p->act.act = A_LIMIT; }
  42
  43 static void free_action(struct action *a)
  44 {
  45   switch (a->act) {
  46     case A_LIE:
  47       xfree(a->u.lie);
  48       break;
  49   }
  50   a->act = A_LIMIT;
  51 }
  52
  53 void free_policy(struct policy *p)
  54   { free_action(&p->act); }
  55
  56 static void print_addrpat(const struct addrops *ao, const struct addrpat *ap)
  57 {
  58   char buf[ADDRLEN];
  59
  60   if (ap->len == 0)
  61     putchar('*');
  62   else {
  63     printf("%s/%u",
  64            inet_ntop(ao->af, &ap->addr, buf, sizeof(buf)),
  65            ap->len);
  66   }
  67 }
  68
  69 static void print_portpat(const struct portpat *pp)
  70 {
  71   if (pp->lo == 0 && pp->hi == 65535) putchar('*');
  72   else if (pp->lo == pp->hi) printf("%u", pp->lo);
  73   else printf("%u-%u", pp->lo, pp->hi);
  74 }
  75
  76 static void print_sockpat(const struct addrops *ao, const struct sockpat *sp)
  77   { print_addrpat(ao, &sp->addr); putchar(' '); print_portpat(&sp->port); }
  78
  79 static const char *const acttab[] = {
  80 #define DEFACT(tag, name) name,
  81   ACTIONS(DEFACT)
  82 #undef DEFACT
  83   0
  84 };
  85
  86 static void print_action(const struct action *act)
  87 {
  88   assert(act->act < A_LIMIT);
  89   printf("%s", acttab[act->act]);
  90   switch (act->act) {
  91     case A_USER: {
  92       int i;
  93       unsigned m;
  94       for (i = 0, m = 1; i < A_LIMIT; i++, m <<= 1)
  95         if (act->u.user & m) printf(" %s", acttab[i]);
  96     } break;
  97     case A_LIE:
  98       printf(" %s", act->u.lie);
  99       break;
 100   }
 101 }
 102
 103 void print_policy(const struct policy *p)
 104 {
 105   print_sockpat(p->ao, &p->sp[L]); putchar(' ');
 106   print_sockpat(p->ao, &p->sp[R]); putchar(' ');
 107   print_action(&p->act); putchar('\n');
 108 }
 109
 110 static int match_portpat(const struct portpat *pp, unsigned port)
 111   { return (pp->lo <= port && port <= pp->hi); }
 112
 113 static int match_sockpat(const struct addrops *ao,
 114                          const struct sockpat *sp, const struct socket *s)
 115 {
 116   return (ao->match_addrpat(&sp->addr, &s->addr) &&
 117           match_portpat(&sp->port, s->port));
 118 }
 119
 120 int match_policy(const struct policy *p, const struct query *q)
 121 {
 122   return ((!p->ao || p->ao == q->ao) &&
 123           match_sockpat(q->ao, &p->sp[L], &q->s[L]) &&
 124           match_sockpat(q->ao, &p->sp[R], &q->s[R]));
 125 }
 126
 127 static void nextline(FILE *fp)
 128 {
 129   for (;;) {
 130     int ch = getc(fp);
 131     if (ch == '\n' || ch == EOF) break;
 132   }
 133 }
 134
 135 static int scan(FILE *fp, char *buf, size_t sz)
 136 {
 137   int ch;
 138
 139 skip_ws:
 140   ch = getc(fp);
 141   switch (ch) {
 142     case '\n':
 143     newline:
 144       ungetc(ch, fp);
 145       return (T_EOL);
 146     case EOF:
 147     eof:
 148       return (ferror(fp) ? T_ERROR : T_EOF);
 149     case '#':
 150       for (;;) {
 151         ch = getc(fp);
 152         if (ch == '\n') goto newline;
 153         else if (ch == EOF) goto eof;
 154       }
 155     default:
 156       if (isspace(ch)) goto skip_ws;
 157       break;
 158   }
 159
 160   for (;;) {
 161     if (sz) { *buf++ = ch; sz--; }
 162     ch = getc(fp);
 163     switch (ch) {
 164       case '\n':
 165         ungetc(ch, fp);
 166         goto done;
 167       case EOF:
 168         goto done;
 169       default:
 170         if (isspace(ch)) goto done;
 171         break;
 172     }
 173   }
 174
 175 done:
 176   if (!sz)
 177     return (T_ERROR);
 178   else {
 179     *buf++ = 0; sz--;
 180     return (T_OK);
 181   }
 182 }
 183
 184 static int parse_actname(FILE *fp, unsigned *act)
 185 {
 186   char buf[32];
 187   int t;
 188   const char *const *p;
 189
 190   if ((t = scan(fp, buf, sizeof(buf))) != 0) return (t);
 191   for (p = acttab; *p; p++)
 192     if (strcmp(buf, *p) == 0) { *act = p - acttab; return (0); }
 193   return (T_ERROR);
 194 }
 195
 196 static int parse_action(FILE *fp, struct action *act)
 197 {
 198   char buf[32];
 199   int t;
 200   unsigned a;
 201   unsigned long m;
 202
 203   if ((t = parse_actname(fp, &a)) != 0) return (t);
 204   switch (a) {
 205     case A_USER:
 206       m = 0;
 207       for (;;) {
 208         if ((t = parse_actname(fp, &a)) != 0) break;
 209         m |= (1 << a);
 210       }
 211       if (t != T_EOL && t != T_EOF) return (t);
 212       act->act = A_USER;
 213       act->u.user = m;
 214       break;
 215     case A_TOKEN:
 216     case A_NAME:
 217     case A_DENY:
 218     case A_HIDE:
 219       act->act = a;
 220       break;
 221     case A_LIE:
 222       if ((t = scan(fp, buf, sizeof(buf))) != 0) return (t);
 223       act->act = a;
 224       act->u.lie = xstrdup(buf);
 225       break;
 226   }
 227   t = scan(fp, buf, sizeof(buf));
 228   if (t != T_EOF && t != T_EOL) {
 229     free_action(act);
 230     return (T_ERROR);
 231   }
 232   return (0);
 233 }
 234
 235 static int parse_sockpat(FILE *fp, const struct addrops **aop,
 236                          struct sockpat *sp)
 237 {
 238   char buf[64];
 239   int t;
 240   const struct addrops *ao;
 241   long n;
 242   char *delim;
 243
 244   if ((t = scan(fp, buf, sizeof(buf))) != 0) return (t);
 245   if (strcmp(buf, "*") == 0)
 246     sp->addr.len = 0;
 247   else {
 248     if (strchr(buf, ':'))
 249       ao = &addroptab[ADDR_IPV6];
 250     else
 251       ao = &addroptab[ADDR_IPV4];
 252     if (!*aop) *aop = ao;
 253     else if (*aop != ao) return (T_ERROR);
 254     delim = strchr(buf, '/');
 255     if (delim) *delim++ = 0;
 256     if (!inet_pton(ao->af, buf, &sp->addr.addr)) return (T_ERROR);
 257     if (!delim) n = ao->len;
 258     else n = strtol(delim, 0, 10);
 259     if (n < 0 || n > ao->len) return (T_ERROR);
 260     sp->addr.len = n;
 261   }
 262
 263   if ((t = scan(fp, buf, sizeof(buf))) != 0) return (T_ERROR);
 264   if (strcmp(buf, "*") == 0) {
 265     sp->port.lo = 0;
 266     sp->port.hi = 65535;
 267   } else {
 268     delim = strchr(buf, '-');
 269     if (delim) *delim++ = 0;
 270     n = strtol(buf, 0, 0);
 271     if (n < 0 || n > 65535) return (T_ERROR);
 272     sp->port.lo = n;
 273     if (!delim)
 274       sp->port.hi = n;
 275     else {
 276       n = strtol(delim, 0, 0);
 277       if (n < 0 || n > 65535) return (T_ERROR);
 278       sp->port.hi = n;
 279     }
 280   }
 281   return (0);
 282 }
 283
 284 int parse_policy(FILE *fp, struct policy *p)
 285 {
 286   int t;
 287
 288   p->ao = 0;
 289   free_policy(p);
 290
 291   if ((t = parse_sockpat(fp, &p->ao, &p->sp[L])) != 0) goto fail;
 292   if ((t = parse_sockpat(fp, &p->ao, &p->sp[R])) != 0) goto err;
 293   if ((t = parse_action(fp, &p->act)) != 0) goto err;
 294   return (0);
 295
 296 err:
 297   t = T_ERROR;
 298 fail:
 299   free_policy(p);
 300   return (t);
 301 }
 302
 303 int open_policy_file(struct policy_file *pf, const char *name,
 304                      const char *what, const struct query *q)
 305 {
 306   if ((pf->fp = fopen(name, "r")) == 0) {
 307     logmsg(q, LOG_ERR, "failed to open %s `%s': %s",
 308            what, name, strerror(errno));
 309     return (-1);
 310   }
 311
 312   pf->name = name;
 313   pf->what = what;
 314   pf->q = q;
 315   pf->err = 0;
 316   pf->lno = 0;
 317   init_policy(&pf->p);
 318   return (0);
 319 }
 320
 321 int read_policy_file(struct policy_file *pf)
 322 {
 323   int t;
 324
 325   for (;;) {
 326     pf->lno++;
 327     t = parse_policy(pf->fp, &pf->p);
 328     switch (t) {
 329       case T_OK:
 330         nextline(pf->fp);
 331         return (0);
 332       case T_ERROR:
 333         logmsg(pf->q, LOG_ERR, "%s:%d: parse error in %s",
 334                pf->name, pf->lno, pf->what);
 335         pf->err = 1;
 336         break;
 337       case T_EOF:
 338         if (ferror(pf->fp)) {
 339           logmsg(pf->q, LOG_ERR, "failed to read %s `%s': %s",
 340                  pf->what, pf->name, strerror(errno));
 341         }
 342         return (-1);
 343       case T_EOL:
 344         nextline(pf->fp);
 345         break;
 346       default:
 347         abort();
 348     }
 349   }
 350 }
 351
 352 void close_policy_file(struct policy_file *pf)
 353 {
 354   fclose(pf->fp);
 355   free_policy(&pf->p);
 356 }
 357
 358 int load_policy_file(const char *file, policy_v *pv)
 359 {
 360   struct policy_file pf;
 361   policy_v v = DA_INIT;
 362
 363   if (open_policy_file(&pf, file, "policy file", 0))
 364     return (-1);
 365   while (!read_policy_file(&pf)) {
 366     DA_PUSH(&v, pf.p);
 367     init_policy(&pf.p);
 368   }
 369   close_policy_file(&pf);
 370   if (!pf.err) {
 371     DA_DESTROY(pv);
 372     *pv = v;
 373     return (0);
 374   } else {
 375     DA_DESTROY(&v);
 376     return (-1);
 377   }
 378 }
 379
 380 /*----- That's all, folks -------------------------------------------------*/