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