mdw@git.distorted.org.uk Git - secnet/blob - util.c

   1 /*
   2  * util.c
   3  * - output and logging support
   4  * - program lifetime support
   5  * - IP address and subnet munging routines
   6  * - MPI convenience functions
   7  */
   8 /*
   9  *  This file is
  10  *    Copyright (C) 1995--2001 Stephen Early <steve@greenend.org.uk>
  11  *
  12  *  It is part of secnet, which is
  13  *    Copyright (C) 1995--2001 Stephen Early <steve@greenend.org.uk>
  14  *    Copyright (C) 1998 Ross Anderson, Eli Biham, Lars Knudsen
  15  *
  16  *  This program is free software; you can redistribute it and/or modify
  17  *  it under the terms of the GNU General Public License as published by
  18  *  the Free Software Foundation; either version 2, or (at your option)
  19  *  any later version.
  20  *
  21  *  This program is distributed in the hope that it will be useful,
  22  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  23  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24  *  GNU General Public License for more details.
  25  *
  26  *  You should have received a copy of the GNU General Public License
  27  *  along with this program; if not, write to the Free Software Foundation,
  28  *  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  29  */
  30
  31 #include "secnet.h"
  32 #include <stdio.h>
  33 #include <string.h>
  34 #include <errno.h>
  35 #include <unistd.h>
  36 #include <limits.h>
  37 #include <assert.h>
  38 #include <sys/wait.h>
  39 #include <adns.h>
  40 #include "util.h"
  41 #include "unaligned.h"
  42 #include "magic.h"
  43
  44 #define MIN_BUFFER_SIZE 64
  45 #define DEFAULT_BUFFER_SIZE 4096
  46 #define MAX_BUFFER_SIZE 131072
  47
  48 static const char *hexdigits="0123456789abcdef";
  49
  50 uint32_t current_phase=0;
  51
  52 struct phase_hook {
  53     hook_fn *fn;
  54     void *state;
  55     struct phase_hook *next;
  56 };
  57
  58 static struct phase_hook *hooks[NR_PHASES]={NULL,};
  59
  60 char *safe_strdup(const char *s, const char *message)
  61 {
  62     char *d;
  63     d=strdup(s);
  64     if (!d) {
  65         fatal_perror("%s",message);
  66     }
  67     return d;
  68 }
  69
  70 void *safe_malloc(size_t size, const char *message)
  71 {
  72     void *r;
  73     r=malloc(size);
  74     if (!r) {
  75         fatal_perror("%s",message);
  76     }
  77     return r;
  78 }
  79 void *safe_malloc_ary(size_t size, size_t count, const char *message) {
  80     if (count >= INT_MAX/size) {
  81         fatal("array allocation overflow: %s", message);
  82     }
  83     return safe_malloc(size*count, message);
  84 }
  85
  86 /* Convert a buffer into its MP_INT representation */
  87 void read_mpbin(MP_INT *a, uint8_t *bin, int binsize)
  88 {
  89     char *buff;
  90     int i;
  91
  92     buff=safe_malloc(binsize*2 + 1,"read_mpbin");
  93
  94     for (i=0; i<binsize; i++) {
  95         buff[i*2]=hexdigits[(bin[i] & 0xf0) >> 4];
  96         buff[i*2+1]=hexdigits[(bin[i] & 0xf)];
  97     }
  98     buff[binsize*2]=0;
  99
 100     mpz_set_str(a, buff, 16);
 101     free(buff);
 102 }
 103
 104 /* Convert a MP_INT into a hex string */
 105 char *write_mpstring(MP_INT *a)
 106 {
 107     char *buff;
 108
 109     buff=safe_malloc(mpz_sizeinbase(a,16)+2,"write_mpstring");
 110     mpz_get_str(buff, 16, a);
 111     return buff;
 112 }
 113
 114 static uint8_t hexval(uint8_t c)
 115 {
 116     switch (c) {
 117     case '0': return 0;
 118     case '1': return 1;
 119     case '2': return 2;
 120     case '3': return 3;
 121     case '4': return 4;
 122     case '5': return 5;
 123     case '6': return 6;
 124     case '7': return 7;
 125     case '8': return 8;
 126     case '9': return 9;
 127     case 'a': return 10;
 128     case 'A': return 10;
 129     case 'b': return 11;
 130     case 'B': return 11;
 131     case 'c': return 12;
 132     case 'C': return 12;
 133     case 'd': return 13;
 134     case 'D': return 13;
 135     case 'e': return 14;
 136     case 'E': return 14;
 137     case 'f': return 15;
 138     case 'F': return 15;
 139     }
 140     return -1;
 141 }
 142
 143 /* Convert a MP_INT into a buffer; return length; truncate if necessary */
 144 int32_t write_mpbin(MP_INT *a, uint8_t *buffer, int32_t buflen)
 145 {
 146     char *hb;
 147     int i,j,l;
 148
 149     if (buflen==0) return 0;
 150     hb=write_mpstring(a);
 151
 152     l=strlen(hb);
 153     i=0; j=0;
 154     if (l&1) {
 155         /* The number starts with a half-byte */
 156         buffer[i++]=hexval(hb[j++]);
 157     }
 158     for (; hb[j] && i<buflen; i++) {
 159         buffer[i]=(hexval(hb[j])<<4)|hexval(hb[j+1]);
 160         j+=2;
 161     }
 162     free(hb);
 163     return i;
 164 }
 165
 166 void setcloexec(int fd) {
 167     int r=fcntl(fd, F_GETFD);
 168     if (r<0) fatal_perror("fcntl(,F_GETFD) failed");
 169     r=fcntl(fd, F_SETFD, r|FD_CLOEXEC);
 170     if (r<0) fatal_perror("fcntl(,F_SETFD,|FD_CLOEXEC) failed");
 171 }
 172
 173 void pipe_cloexec(int fd[2]) {
 174     int r=pipe(fd);
 175     if (r) fatal_perror("pipe");
 176     setcloexec(fd[0]);
 177     setcloexec(fd[1]);
 178 }
 179
 180 static const char *phases[NR_PHASES]={
 181     "PHASE_INIT",
 182     "PHASE_GETOPTS",
 183     "PHASE_READCONFIG",
 184     "PHASE_SETUP",
 185     "PHASE_DAEMONIZE",
 186     "PHASE_GETRESOURCES",
 187     "PHASE_DROPPRIV",
 188     "PHASE_RUN",
 189     "PHASE_SHUTDOWN"
 190 };
 191
 192 void enter_phase(uint32_t new_phase)
 193 {
 194     struct phase_hook *i;
 195
 196     if (hooks[new_phase])
 197         Message(M_DEBUG_PHASE,"Running hooks for %s...\n", phases[new_phase]);
 198     current_phase=new_phase;
 199
 200     for (i=hooks[new_phase]; i; i=i->next)
 201         i->fn(i->state, new_phase);
 202     Message(M_DEBUG_PHASE,"Now in %s\n",phases[new_phase]);
 203 }
 204
 205 bool_t add_hook(uint32_t phase, hook_fn *fn, void *state)
 206 {
 207     struct phase_hook *h;
 208
 209     h=safe_malloc(sizeof(*h),"add_hook");
 210     h->fn=fn;
 211     h->state=state;
 212     h->next=hooks[phase];
 213     hooks[phase]=h;
 214     return True;
 215 }
 216
 217 bool_t remove_hook(uint32_t phase, hook_fn *fn, void *state)
 218 {
 219     fatal("remove_hook: not implemented");
 220
 221     return False;
 222 }
 223
 224 void vslilog(struct log_if *lf, int priority, const char *message, va_list ap)
 225 {
 226     lf->vlogfn(lf->st,priority,message,ap);
 227 }
 228
 229 void slilog(struct log_if *lf, int priority, const char *message, ...)
 230 {
 231     va_list ap;
 232
 233     va_start(ap,message);
 234     vslilog(lf,priority,message,ap);
 235     va_end(ap);
 236 }
 237
 238 struct buffer {
 239     closure_t cl;
 240     struct buffer_if ops;
 241 };
 242
 243 void buffer_assert_free(struct buffer_if *buffer, cstring_t file,
 244                         int line)
 245 {
 246     if (!buffer->free) {
 247         fprintf(stderr,"secnet: BUF_ASSERT_FREE, %s line %d, owned by %s",
 248                 file,line,buffer->owner);
 249         assert(!"buffer_assert_free failure");
 250     }
 251 }
 252
 253 void buffer_assert_used(struct buffer_if *buffer, cstring_t file,
 254                         int line)
 255 {
 256     if (buffer->free) {
 257         fprintf(stderr,"secnet: BUF_ASSERT_USED, %s line %d, last owned by %s",
 258                 file,line,buffer->owner);
 259         assert(!"buffer_assert_used failure");
 260     }
 261 }
 262
 263 void buffer_init(struct buffer_if *buffer, int32_t max_start_pad)
 264 {
 265     assert(max_start_pad<=buffer->alloclen);
 266     buffer->start=buffer->base+max_start_pad;
 267     buffer->size=0;
 268 }
 269
 270 void *buf_append(struct buffer_if *buf, int32_t amount) {
 271     void *p;
 272     assert(amount <= buf_remaining_space(buf));
 273     p=buf->start + buf->size;
 274     buf->size+=amount;
 275     return p;
 276 }
 277
 278 void *buf_prepend(struct buffer_if *buf, int32_t amount) {
 279     assert(amount <= buf->start - buf->base);
 280     buf->size+=amount;
 281     return buf->start-=amount;
 282 }
 283
 284 void *buf_unappend(struct buffer_if *buf, int32_t amount) {
 285     if (buf->size < amount) return 0;
 286     return buf->start+(buf->size-=amount);
 287 }
 288
 289 void *buf_unprepend(struct buffer_if *buf, int32_t amount) {
 290     void *p;
 291     if (buf->size < amount) return 0;
 292     p=buf->start;
 293     buf->start+=amount;
 294     buf->size-=amount;
 295     return p;
 296 }
 297
 298 /* Append a two-byte length and the string to the buffer. Length is in
 299    network byte order. */
 300 void buf_append_string(struct buffer_if *buf, cstring_t s)
 301 {
 302     size_t len;
 303
 304     len=strlen(s);
 305     /* fixme: if string is longer than 65535, result is a corrupted packet */
 306     buf_append_uint16(buf,len);
 307     BUF_ADD_BYTES(append,buf,s,len);
 308 }
 309
 310 void buffer_new(struct buffer_if *buf, int32_t len)
 311 {
 312     buf->free=True;
 313     buf->owner=NULL;
 314     buf->flags=0;
 315     buf->loc.file=NULL;
 316     buf->loc.line=0;
 317     buf->size=0;
 318     buf->alloclen=len;
 319     buf->start=NULL;
 320     buf->base=safe_malloc(len,"buffer_new");
 321 }
 322
 323 void buffer_readonly_view(struct buffer_if *buf, const void *data, int32_t len)
 324 {
 325     buf->free=False;
 326     buf->owner="READONLY";
 327     buf->flags=0;
 328     buf->loc.file=NULL;
 329     buf->loc.line=0;
 330     buf->size=buf->alloclen=len;
 331     buf->base=buf->start=(uint8_t*)data;
 332 }
 333
 334 void buffer_readonly_clone(struct buffer_if *out, const struct buffer_if *in)
 335 {
 336     buffer_readonly_view(out,in->start,in->size);
 337 }
 338
 339 void buffer_copy(struct buffer_if *dst, const struct buffer_if *src)
 340 {
 341     if (dst->alloclen < src->alloclen) {
 342         dst->base=realloc(dst->base,src->alloclen);
 343         if (!dst->base) fatal_perror("buffer_copy");
 344         dst->alloclen = src->alloclen;
 345     }
 346     dst->start = dst->base + (src->start - src->base);
 347     dst->size = src->size;
 348     memcpy(dst->start, src->start, dst->size);
 349 }
 350
 351 static list_t *buffer_apply(closure_t *self, struct cloc loc, dict_t *context,
 352                             list_t *args)
 353 {
 354     struct buffer *st;
 355     item_t *item;
 356     dict_t *dict;
 357     bool_t lockdown=False;
 358     uint32_t len=DEFAULT_BUFFER_SIZE;
 359
 360     st=safe_malloc(sizeof(*st),"buffer_apply");
 361     st->cl.description="buffer";
 362     st->cl.type=CL_BUFFER;
 363     st->cl.apply=NULL;
 364     st->cl.interface=&st->ops;
 365
 366     /* First argument, if present, is buffer length */
 367     item=list_elem(args,0);
 368     if (item) {
 369         if (item->type!=t_number) {
 370             cfgfatal(st->ops.loc,"buffer","first parameter must be a "
 371                      "number (buffer size)\n");
 372         }
 373         len=item->data.number;
 374         if (len<MIN_BUFFER_SIZE) {
 375             cfgfatal(st->ops.loc,"buffer","ludicrously small buffer size\n");
 376         }
 377         if (len>MAX_BUFFER_SIZE) {
 378             cfgfatal(st->ops.loc,"buffer","ludicrously large buffer size\n");
 379         }
 380     }
 381     /* Second argument, if present, is a dictionary */
 382     item=list_elem(args,1);
 383     if (item) {
 384         if (item->type!=t_dict) {
 385             cfgfatal(st->ops.loc,"buffer","second parameter must be a "
 386                      "dictionary\n");
 387         }
 388         dict=item->data.dict;
 389         lockdown=dict_read_bool(dict,"lockdown",False,"buffer",st->ops.loc,
 390                                 False);
 391     }
 392
 393     buffer_new(&st->ops,len);
 394     if (lockdown) {
 395         /* XXX mlock the buffer if possible */
 396     }
 397
 398     return new_closure(&st->cl);
 399 }
 400
 401 void send_nak(const struct comm_addr *dest, uint32_t our_index,
 402               uint32_t their_index, uint32_t msgtype,
 403               struct buffer_if *buf, const char *logwhy)
 404 {
 405     buffer_init(buf,calculate_max_start_pad());
 406     buf_append_uint32(buf,their_index);
 407     buf_append_uint32(buf,our_index);
 408     buf_append_uint32(buf,LABEL_NAK);
 409     if (logwhy)
 410         Message(M_INFO,"%s: %08"PRIx32"<-%08"PRIx32": %08"PRIx32":"
 411                 " %s; sending NAK\n",
 412                 comm_addr_to_string(dest),
 413                 our_index, their_index, msgtype, logwhy);
 414     dest->comm->sendmsg(dest->comm->st, buf, dest);
 415 }
 416
 417 int consttime_memeq(const void *s1in, const void *s2in, size_t n)
 418 {
 419     const uint8_t *s1=s1in, *s2=s2in;
 420     register volatile uint8_t accumulator=0;
 421
 422     while (n-- > 0) {
 423         accumulator |= (*s1++ ^ *s2++);
 424     }
 425     accumulator |= accumulator >> 4; /* constant-time             */
 426     accumulator |= accumulator >> 2; /*  boolean canonicalisation */
 427     accumulator |= accumulator >> 1;
 428     accumulator &= 1;
 429     accumulator ^= 1;
 430     return accumulator;
 431 }
 432
 433 void util_module(dict_t *dict)
 434 {
 435     add_closure(dict,"sysbuffer",buffer_apply);
 436 }
 437
 438 void update_max_start_pad(int32_t *our_module_global, int32_t our_instance)
 439 {
 440     if (*our_module_global < our_instance)
 441         *our_module_global=our_instance;
 442 }
 443
 444 int32_t transform_max_start_pad, comm_max_start_pad;
 445
 446 int32_t calculate_max_start_pad(void)
 447 {
 448     return
 449         site_max_start_pad +
 450         transform_max_start_pad +
 451         comm_max_start_pad;
 452 }
 453
 454 void vslilog_part(struct log_if *lf, int priority, const char *message, va_list ap)
 455 {
 456     char *buff=lf->buff;
 457     size_t bp;
 458     char *nlp;
 459
 460     bp=strlen(buff);
 461     assert(bp < LOG_MESSAGE_BUFLEN);
 462     vsnprintf(buff+bp,LOG_MESSAGE_BUFLEN-bp,message,ap);
 463     buff[LOG_MESSAGE_BUFLEN-1] = '\n';
 464     buff[LOG_MESSAGE_BUFLEN] = '\0';
 465     /* Each line is sent separately */
 466     while ((nlp=strchr(buff,'\n'))) {
 467         *nlp=0;
 468         slilog(lf,priority,"%s",buff);
 469         memmove(buff,nlp+1,strlen(nlp+1)+1);
 470     }
 471 }
 472
 473 extern void slilog_part(struct log_if *lf, int priority, const char *message, ...)
 474 {
 475     va_list ap;
 476     va_start(ap,message);
 477     vslilog_part(lf,priority,message,ap);
 478     va_end(ap);
 479 }
 480
 481 #define IADDR_NBUFS_SHIFT 3
 482 #define IADDR_NBUFS (1 << IADDR_NBUFS_SHIFT)
 483
 484 const char *iaddr_to_string(const union iaddr *ia)
 485 {
 486     static int b;
 487
 488     b++;
 489     b &= IADDR_NBUFS-1;
 490
 491 #ifndef CONFIG_IPV6
 492
 493     static char bufs[IADDR_NBUFS][100];
 494
 495     assert(ia->sa.sa_family == AF_INET);
 496
 497     snprintf(bufs[b], sizeof(bufs[b]), "[%s]:%d",
 498              inet_ntoa(ia->sin.sin_addr),
 499              ntohs(ia->sin.sin_port));
 500
 501 #else /* CONFIG_IPV6 => we have adns_addr2text */
 502
 503     static char bufs[IADDR_NBUFS][1+ADNS_ADDR2TEXT_BUFLEN+20];
 504
 505     int port;
 506
 507     char *addrbuf = bufs[b];
 508     *addrbuf++ = '[';
 509     int addrbuflen = ADNS_ADDR2TEXT_BUFLEN;
 510
 511     int r = adns_addr2text(&ia->sa, 0, addrbuf, &addrbuflen, &port);
 512     if (r) {
 513         const char fmt[]= "scoped IPv6 addr, error: %.*s";
 514         sprintf(addrbuf, fmt,
 515                 ADNS_ADDR2TEXT_BUFLEN - sizeof(fmt) /* underestimate */,
 516                 strerror(r));
 517     }
 518
 519     char *portbuf = addrbuf;
 520     int addrl = strlen(addrbuf);
 521     portbuf += addrl;
 522
 523     snprintf(portbuf, sizeof(bufs[b])-addrl, "]:%d", port);
 524
 525 #endif /* CONFIG_IPV6 */
 526
 527     return bufs[b];
 528 }
 529
 530 bool_t iaddr_equal(const union iaddr *ia, const union iaddr *ib)
 531 {
 532     if (ia->sa.sa_family != ib->sa.sa_family)
 533         return 0;
 534     switch (ia->sa.sa_family) {
 535     case AF_INET:
 536         return ia->sin.sin_addr.s_addr == ib->sin.sin_addr.s_addr
 537             && ia->sin.sin_port        == ib->sin.sin_port;
 538 #ifdef CONFIG_IPV6
 539     case AF_INET6:
 540         return !memcmp(&ia->sin6.sin6_addr, &ib->sin6.sin6_addr, 16)
 541             && ia->sin6.sin6_scope_id  == ib->sin6.sin6_scope_id
 542             && ia->sin6.sin6_port      == ib->sin6.sin6_port
 543             /* we ignore the flowinfo field */;
 544 #endif /* CONFIG_IPV6 */
 545     default:
 546         abort();
 547     }
 548 }
 549
 550 int iaddr_socklen(const union iaddr *ia)
 551 {
 552     switch (ia->sa.sa_family) {
 553     case AF_INET:  return sizeof(ia->sin);
 554 #ifdef CONFIG_IPV6
 555     case AF_INET6: return sizeof(ia->sin6);
 556 #endif /* CONFIG_IPV6 */
 557     default:       abort();
 558     }
 559 }