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 #include "ipaddr.h"
  44
  45 #define MIN_BUFFER_SIZE 64
  46 #define DEFAULT_BUFFER_SIZE 4096
  47 #define MAX_BUFFER_SIZE 131072
  48
  49 static const char *hexdigits="0123456789abcdef";
  50
  51 uint32_t current_phase=0;
  52
  53 struct phase_hook {
  54     hook_fn *fn;
  55     void *state;
  56     struct phase_hook *next;
  57 };
  58
  59 static struct phase_hook *hooks[NR_PHASES]={NULL,};
  60
  61 char *safe_strdup(const char *s, const char *message)
  62 {
  63     char *d;
  64     d=strdup(s);
  65     if (!d) {
  66         fatal_perror("%s",message);
  67     }
  68     return d;
  69 }
  70
  71 void *safe_malloc(size_t size, const char *message)
  72 {
  73     void *r;
  74     if (!size)
  75         return 0;
  76     r=malloc(size);
  77     if (!r) {
  78         fatal_perror("%s",message);
  79     }
  80     return r;
  81 }
  82 void *safe_realloc_ary(void *p, size_t size, size_t count,
  83                        const char *message) {
  84     if (count >= INT_MAX/size) {
  85         fatal("array allocation overflow: %s", message);
  86     }
  87     assert(size && count);
  88     p = realloc(p, size*count);
  89     if (!p)
  90         fatal_perror("%s", message);
  91     return p;
  92 }
  93
  94 void *safe_malloc_ary(size_t size, size_t count, const char *message) {
  95     if (!size || !count)
  96         return 0;
  97     return safe_realloc_ary(0,size,count,message);
  98 }
  99
 100 /* Convert a buffer into its MP_INT representation */
 101 void read_mpbin(MP_INT *a, uint8_t *bin, int binsize)
 102 {
 103     char *buff;
 104     int i;
 105
 106     buff=safe_malloc(binsize*2 + 1,"read_mpbin");
 107
 108     for (i=0; i<binsize; i++) {
 109         buff[i*2]=hexdigits[(bin[i] & 0xf0) >> 4];
 110         buff[i*2+1]=hexdigits[(bin[i] & 0xf)];
 111     }
 112     buff[binsize*2]=0;
 113
 114     mpz_set_str(a, buff, 16);
 115     free(buff);
 116 }
 117
 118 /* Convert a MP_INT into a hex string */
 119 char *write_mpstring(MP_INT *a)
 120 {
 121     char *buff;
 122
 123     buff=safe_malloc(mpz_sizeinbase(a,16)+2,"write_mpstring");
 124     mpz_get_str(buff, 16, a);
 125     return buff;
 126 }
 127
 128 static uint8_t hexval(uint8_t c)
 129 {
 130     switch (c) {
 131     case '0': return 0;
 132     case '1': return 1;
 133     case '2': return 2;
 134     case '3': return 3;
 135     case '4': return 4;
 136     case '5': return 5;
 137     case '6': return 6;
 138     case '7': return 7;
 139     case '8': return 8;
 140     case '9': return 9;
 141     case 'a': return 10;
 142     case 'A': return 10;
 143     case 'b': return 11;
 144     case 'B': return 11;
 145     case 'c': return 12;
 146     case 'C': return 12;
 147     case 'd': return 13;
 148     case 'D': return 13;
 149     case 'e': return 14;
 150     case 'E': return 14;
 151     case 'f': return 15;
 152     case 'F': return 15;
 153     }
 154     return -1;
 155 }
 156
 157 /* Convert a MP_INT into a buffer; return length; truncate if necessary */
 158 int32_t write_mpbin(MP_INT *a, uint8_t *buffer, int32_t buflen)
 159 {
 160     char *hb;
 161     int i,j,l;
 162
 163     if (buflen==0) return 0;
 164     hb=write_mpstring(a);
 165
 166     l=strlen(hb);
 167     i=0; j=0;
 168     if (l&1) {
 169         /* The number starts with a half-byte */
 170         buffer[i++]=hexval(hb[j++]);
 171     }
 172     for (; hb[j] && i<buflen; i++) {
 173         buffer[i]=(hexval(hb[j])<<4)|hexval(hb[j+1]);
 174         j+=2;
 175     }
 176     free(hb);
 177     return i;
 178 }
 179
 180 void setcloexec(int fd) {
 181     int r=fcntl(fd, F_GETFD);
 182     if (r<0) fatal_perror("fcntl(,F_GETFD) failed");
 183     r=fcntl(fd, F_SETFD, r|FD_CLOEXEC);
 184     if (r<0) fatal_perror("fcntl(,F_SETFD,|FD_CLOEXEC) failed");
 185 }
 186
 187 void pipe_cloexec(int fd[2]) {
 188     int r=pipe(fd);
 189     if (r) fatal_perror("pipe");
 190     setcloexec(fd[0]);
 191     setcloexec(fd[1]);
 192 }
 193
 194 static const char *phases[NR_PHASES]={
 195     "PHASE_INIT",
 196     "PHASE_GETOPTS",
 197     "PHASE_READCONFIG",
 198     "PHASE_SETUP",
 199     "PHASE_DAEMONIZE",
 200     "PHASE_GETRESOURCES",
 201     "PHASE_DROPPRIV",
 202     "PHASE_RUN",
 203     "PHASE_SHUTDOWN"
 204 };
 205
 206 void enter_phase(uint32_t new_phase)
 207 {
 208     struct phase_hook *i;
 209
 210     if (hooks[new_phase])
 211         Message(M_DEBUG_PHASE,"Running hooks for %s...\n", phases[new_phase]);
 212     current_phase=new_phase;
 213
 214     for (i=hooks[new_phase]; i; i=i->next)
 215         i->fn(i->state, new_phase);
 216     Message(M_DEBUG_PHASE,"Now in %s\n",phases[new_phase]);
 217 }
 218
 219 bool_t add_hook(uint32_t phase, hook_fn *fn, void *state)
 220 {
 221     struct phase_hook *h;
 222
 223     h=safe_malloc(sizeof(*h),"add_hook");
 224     h->fn=fn;
 225     h->state=state;
 226     h->next=hooks[phase];
 227     hooks[phase]=h;
 228     return True;
 229 }
 230
 231 bool_t remove_hook(uint32_t phase, hook_fn *fn, void *state)
 232 {
 233     fatal("remove_hook: not implemented");
 234
 235     return False;
 236 }
 237
 238 void vslilog(struct log_if *lf, int priority, const char *message, va_list ap)
 239 {
 240     lf->vlogfn(lf->st,priority,message,ap);
 241 }
 242
 243 void slilog(struct log_if *lf, int priority, const char *message, ...)
 244 {
 245     va_list ap;
 246
 247     va_start(ap,message);
 248     vslilog(lf,priority,message,ap);
 249     va_end(ap);
 250 }
 251
 252 struct buffer {
 253     closure_t cl;
 254     struct buffer_if ops;
 255 };
 256
 257 void buffer_assert_free(struct buffer_if *buffer, cstring_t file,
 258                         int line)
 259 {
 260     if (!buffer->free) {
 261         fprintf(stderr,"secnet: BUF_ASSERT_FREE, %s line %d, owned by %s",
 262                 file,line,buffer->owner);
 263         assert(!"buffer_assert_free failure");
 264     }
 265 }
 266
 267 void buffer_assert_used(struct buffer_if *buffer, cstring_t file,
 268                         int line)
 269 {
 270     if (buffer->free) {
 271         fprintf(stderr,"secnet: BUF_ASSERT_USED, %s line %d, last owned by %s",
 272                 file,line,buffer->owner);
 273         assert(!"buffer_assert_used failure");
 274     }
 275 }
 276
 277 void buffer_init(struct buffer_if *buffer, int32_t max_start_pad)
 278 {
 279     assert(max_start_pad<=buffer->alloclen);
 280     buffer->start=buffer->base+max_start_pad;
 281     buffer->size=0;
 282 }
 283
 284 void *buf_append(struct buffer_if *buf, int32_t amount) {
 285     void *p;
 286     assert(amount <= buf_remaining_space(buf));
 287     p=buf->start + buf->size;
 288     buf->size+=amount;
 289     return p;
 290 }
 291
 292 void *buf_prepend(struct buffer_if *buf, int32_t amount) {
 293     assert(amount <= buf->start - buf->base);
 294     buf->size+=amount;
 295     return buf->start-=amount;
 296 }
 297
 298 void *buf_unappend(struct buffer_if *buf, int32_t amount) {
 299     if (buf->size < amount) return 0;
 300     return buf->start+(buf->size-=amount);
 301 }
 302
 303 void *buf_unprepend(struct buffer_if *buf, int32_t amount) {
 304     void *p;
 305     if (buf->size < amount) return 0;
 306     p=buf->start;
 307     buf->start+=amount;
 308     buf->size-=amount;
 309     return p;
 310 }
 311
 312 /* Append a two-byte length and the string to the buffer. Length is in
 313    network byte order. */
 314 void buf_append_string(struct buffer_if *buf, cstring_t s)
 315 {
 316     size_t len;
 317
 318     len=strlen(s);
 319     /* fixme: if string is longer than 65535, result is a corrupted packet */
 320     buf_append_uint16(buf,len);
 321     BUF_ADD_BYTES(append,buf,s,len);
 322 }
 323
 324 void buffer_new(struct buffer_if *buf, int32_t len)
 325 {
 326     buf->free=True;
 327     buf->owner=NULL;
 328     buf->flags=0;
 329     buf->loc.file=NULL;
 330     buf->loc.line=0;
 331     buf->size=0;
 332     buf->alloclen=len;
 333     buf->start=NULL;
 334     buf->base=safe_malloc(len,"buffer_new");
 335 }
 336
 337 void buffer_readonly_view(struct buffer_if *buf, const void *data, int32_t len)
 338 {
 339     buf->free=False;
 340     buf->owner="READONLY";
 341     buf->flags=0;
 342     buf->loc.file=NULL;
 343     buf->loc.line=0;
 344     buf->size=buf->alloclen=len;
 345     buf->base=buf->start=(uint8_t*)data;
 346 }
 347
 348 void buffer_readonly_clone(struct buffer_if *out, const struct buffer_if *in)
 349 {
 350     buffer_readonly_view(out,in->start,in->size);
 351 }
 352
 353 void buffer_copy(struct buffer_if *dst, const struct buffer_if *src)
 354 {
 355     if (dst->alloclen < src->alloclen) {
 356         dst->base=realloc(dst->base,src->alloclen);
 357         if (!dst->base) fatal_perror("buffer_copy");
 358         dst->alloclen = src->alloclen;
 359     }
 360     dst->start = dst->base + (src->start - src->base);
 361     dst->size = src->size;
 362     memcpy(dst->start, src->start, dst->size);
 363 }
 364
 365 static list_t *buffer_apply(closure_t *self, struct cloc loc, dict_t *context,
 366                             list_t *args)
 367 {
 368     struct buffer *st;
 369     item_t *item;
 370     dict_t *dict;
 371     bool_t lockdown=False;
 372     uint32_t len=DEFAULT_BUFFER_SIZE;
 373
 374     st=safe_malloc(sizeof(*st),"buffer_apply");
 375     st->cl.description="buffer";
 376     st->cl.type=CL_BUFFER;
 377     st->cl.apply=NULL;
 378     st->cl.interface=&st->ops;
 379
 380     /* First argument, if present, is buffer length */
 381     item=list_elem(args,0);
 382     if (item) {
 383         if (item->type!=t_number) {
 384             cfgfatal(st->ops.loc,"buffer","first parameter must be a "
 385                      "number (buffer size)\n");
 386         }
 387         len=item->data.number;
 388         if (len<MIN_BUFFER_SIZE) {
 389             cfgfatal(st->ops.loc,"buffer","ludicrously small buffer size\n");
 390         }
 391         if (len>MAX_BUFFER_SIZE) {
 392             cfgfatal(st->ops.loc,"buffer","ludicrously large buffer size\n");
 393         }
 394     }
 395     /* Second argument, if present, is a dictionary */
 396     item=list_elem(args,1);
 397     if (item) {
 398         if (item->type!=t_dict) {
 399             cfgfatal(st->ops.loc,"buffer","second parameter must be a "
 400                      "dictionary\n");
 401         }
 402         dict=item->data.dict;
 403         lockdown=dict_read_bool(dict,"lockdown",False,"buffer",st->ops.loc,
 404                                 False);
 405     }
 406
 407     buffer_new(&st->ops,len);
 408     if (lockdown) {
 409         /* XXX mlock the buffer if possible */
 410     }
 411
 412     return new_closure(&st->cl);
 413 }
 414
 415 void send_nak(const struct comm_addr *dest, uint32_t our_index,
 416               uint32_t their_index, uint32_t msgtype,
 417               struct buffer_if *buf, const char *logwhy)
 418 {
 419     buffer_init(buf,calculate_max_start_pad());
 420     buf_append_uint32(buf,their_index);
 421     buf_append_uint32(buf,our_index);
 422     buf_append_uint32(buf,LABEL_NAK);
 423     if (logwhy)
 424         Message(M_INFO,"%s: %08"PRIx32"<-%08"PRIx32": %08"PRIx32":"
 425                 " %s; sending NAK\n",
 426                 comm_addr_to_string(dest),
 427                 our_index, their_index, msgtype, logwhy);
 428     dest->comm->sendmsg(dest->comm->st, buf, dest);
 429 }
 430
 431 int consttime_memeq(const void *s1in, const void *s2in, size_t n)
 432 {
 433     const uint8_t *s1=s1in, *s2=s2in;
 434     register volatile uint8_t accumulator=0;
 435
 436     while (n-- > 0) {
 437         accumulator |= (*s1++ ^ *s2++);
 438     }
 439     accumulator |= accumulator >> 4; /* constant-time             */
 440     accumulator |= accumulator >> 2; /*  boolean canonicalisation */
 441     accumulator |= accumulator >> 1;
 442     accumulator &= 1;
 443     accumulator ^= 1;
 444     return accumulator;
 445 }
 446
 447 void util_module(dict_t *dict)
 448 {
 449     add_closure(dict,"sysbuffer",buffer_apply);
 450 }
 451
 452 void update_max_start_pad(int32_t *our_module_global, int32_t our_instance)
 453 {
 454     if (*our_module_global < our_instance)
 455         *our_module_global=our_instance;
 456 }
 457
 458 int32_t transform_max_start_pad, comm_max_start_pad;
 459
 460 int32_t calculate_max_start_pad(void)
 461 {
 462     return
 463         site_max_start_pad +
 464         transform_max_start_pad +
 465         comm_max_start_pad;
 466 }
 467
 468 void vslilog_part(struct log_if *lf, int priority, const char *message, va_list ap)
 469 {
 470     char *buff=lf->buff;
 471     size_t bp;
 472     char *nlp;
 473
 474     bp=strlen(buff);
 475     assert(bp < LOG_MESSAGE_BUFLEN);
 476     vsnprintf(buff+bp,LOG_MESSAGE_BUFLEN-bp,message,ap);
 477     buff[LOG_MESSAGE_BUFLEN-1] = '\n';
 478     buff[LOG_MESSAGE_BUFLEN] = '\0';
 479     /* Each line is sent separately */
 480     while ((nlp=strchr(buff,'\n'))) {
 481         *nlp=0;
 482         slilog(lf,priority,"%s",buff);
 483         memmove(buff,nlp+1,strlen(nlp+1)+1);
 484     }
 485 }
 486
 487 extern void slilog_part(struct log_if *lf, int priority, const char *message, ...)
 488 {
 489     va_list ap;
 490     va_start(ap,message);
 491     vslilog_part(lf,priority,message,ap);
 492     va_end(ap);
 493 }
 494
 495 void string_item_to_iaddr(const item_t *item, uint16_t port, union iaddr *ia,
 496                           const char *desc)
 497 {
 498 #ifndef CONFIG_IPV6
 499
 500     ia->sin.sin_family=AF_INET;
 501     ia->sin.sin_addr.s_addr=string_item_to_ipaddr(item,desc);
 502
 503 #else /* CONFIG_IPV6 => we have adns_text2addr */
 504
 505     if (item->type!=t_string)
 506         cfgfatal(item->loc,desc,"expecting a string IP (v4 or v6) address\n");
 507     socklen_t salen=sizeof(*ia);
 508     int r=adns_text2addr(item->data.string, port,
 509                          adns_qf_addrlit_ipv4_quadonly,
 510                          &ia->sa, &salen);
 511     assert(r!=ENOSPC);
 512     if (r) cfgfatal(item->loc,desc,"invalid IP (v4 or v6) address: %s\n",
 513                     strerror(r));
 514
 515 #endif /* CONFIG_IPV6 */
 516 }
 517
 518 #define IADDR_NBUFS_SHIFT 3
 519 #define IADDR_NBUFS (1 << IADDR_NBUFS_SHIFT)
 520
 521 const char *iaddr_to_string(const union iaddr *ia)
 522 {
 523     static int b;
 524
 525     b++;
 526     b &= IADDR_NBUFS-1;
 527
 528 #ifndef CONFIG_IPV6
 529
 530     static char bufs[IADDR_NBUFS][100];
 531
 532     assert(ia->sa.sa_family == AF_INET);
 533
 534     snprintf(bufs[b], sizeof(bufs[b]), "[%s]:%d",
 535              inet_ntoa(ia->sin.sin_addr),
 536              ntohs(ia->sin.sin_port));
 537
 538 #else /* CONFIG_IPV6 => we have adns_addr2text */
 539
 540     static char bufs[IADDR_NBUFS][1+ADNS_ADDR2TEXT_BUFLEN+20];
 541
 542     int port;
 543
 544     char *addrbuf = bufs[b];
 545     *addrbuf++ = '[';
 546     int addrbuflen = ADNS_ADDR2TEXT_BUFLEN;
 547
 548     int r = adns_addr2text(&ia->sa, 0, addrbuf, &addrbuflen, &port);
 549     if (r) {
 550         const char fmt[]= "scoped IPv6 addr, error: %.*s";
 551         sprintf(addrbuf, fmt,
 552                 ADNS_ADDR2TEXT_BUFLEN - sizeof(fmt) /* underestimate */,
 553                 strerror(r));
 554     }
 555
 556     char *portbuf = addrbuf;
 557     int addrl = strlen(addrbuf);
 558     portbuf += addrl;
 559
 560     snprintf(portbuf, sizeof(bufs[b])-addrl, "]:%d", port);
 561
 562 #endif /* CONFIG_IPV6 */
 563
 564     return bufs[b];
 565 }
 566
 567 bool_t iaddr_equal(const union iaddr *ia, const union iaddr *ib)
 568 {
 569     if (ia->sa.sa_family != ib->sa.sa_family)
 570         return 0;
 571     switch (ia->sa.sa_family) {
 572     case AF_INET:
 573         return ia->sin.sin_addr.s_addr == ib->sin.sin_addr.s_addr
 574             && ia->sin.sin_port        == ib->sin.sin_port;
 575 #ifdef CONFIG_IPV6
 576     case AF_INET6:
 577         return !memcmp(&ia->sin6.sin6_addr, &ib->sin6.sin6_addr, 16)
 578             && ia->sin6.sin6_scope_id  == ib->sin6.sin6_scope_id
 579             && ia->sin6.sin6_port      == ib->sin6.sin6_port
 580             /* we ignore the flowinfo field */;
 581 #endif /* CONFIG_IPV6 */
 582     default:
 583         abort();
 584     }
 585 }
 586
 587 int iaddr_socklen(const union iaddr *ia)
 588 {
 589     switch (ia->sa.sa_family) {
 590     case AF_INET:  return sizeof(ia->sin);
 591 #ifdef CONFIG_IPV6
 592     case AF_INET6: return sizeof(ia->sin6);
 593 #endif /* CONFIG_IPV6 */
 594     default:       abort();
 595     }
 596 }