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 "util.h"
  40 #include "unaligned.h"
  41 #include "magic.h"
  42
  43 #define MIN_BUFFER_SIZE 64
  44 #define DEFAULT_BUFFER_SIZE 4096
  45 #define MAX_BUFFER_SIZE 131072
  46
  47 static const char *hexdigits="0123456789abcdef";
  48
  49 uint32_t current_phase=0;
  50
  51 struct phase_hook {
  52     hook_fn *fn;
  53     void *state;
  54     struct phase_hook *next;
  55 };
  56
  57 static struct phase_hook *hooks[NR_PHASES]={NULL,};
  58
  59 char *safe_strdup(const char *s, const char *message)
  60 {
  61     char *d;
  62     d=strdup(s);
  63     if (!d) {
  64         fatal_perror(message);
  65     }
  66     return d;
  67 }
  68
  69 void *safe_malloc(size_t size, const char *message)
  70 {
  71     void *r;
  72     r=malloc(size);
  73     if (!r) {
  74         fatal_perror(message);
  75     }
  76     return r;
  77 }
  78 void *safe_malloc_ary(size_t size, size_t count, const char *message) {
  79     if (count >= INT_MAX/size) {
  80         fatal("array allocation overflow: %s", message);
  81     }
  82     return safe_malloc(size*count, message);
  83 }
  84
  85 /* Convert a buffer into its MP_INT representation */
  86 void read_mpbin(MP_INT *a, uint8_t *bin, int binsize)
  87 {
  88     char *buff;
  89     int i;
  90
  91     buff=safe_malloc(binsize*2 + 1,"read_mpbin");
  92
  93     for (i=0; i<binsize; i++) {
  94         buff[i*2]=hexdigits[(bin[i] & 0xf0) >> 4];
  95         buff[i*2+1]=hexdigits[(bin[i] & 0xf)];
  96     }
  97     buff[binsize*2]=0;
  98
  99     mpz_set_str(a, buff, 16);
 100     free(buff);
 101 }
 102
 103 /* Convert a MP_INT into a hex string */
 104 char *write_mpstring(MP_INT *a)
 105 {
 106     char *buff;
 107
 108     buff=safe_malloc(mpz_sizeinbase(a,16)+2,"write_mpstring");
 109     mpz_get_str(buff, 16, a);
 110     return buff;
 111 }
 112
 113 static uint8_t hexval(uint8_t c)
 114 {
 115     switch (c) {
 116     case '0': return 0;
 117     case '1': return 1;
 118     case '2': return 2;
 119     case '3': return 3;
 120     case '4': return 4;
 121     case '5': return 5;
 122     case '6': return 6;
 123     case '7': return 7;
 124     case '8': return 8;
 125     case '9': return 9;
 126     case 'a': return 10;
 127     case 'A': return 10;
 128     case 'b': return 11;
 129     case 'B': return 11;
 130     case 'c': return 12;
 131     case 'C': return 12;
 132     case 'd': return 13;
 133     case 'D': return 13;
 134     case 'e': return 14;
 135     case 'E': return 14;
 136     case 'f': return 15;
 137     case 'F': return 15;
 138     }
 139     return -1;
 140 }
 141
 142 /* Convert a MP_INT into a buffer; return length; truncate if necessary */
 143 int32_t write_mpbin(MP_INT *a, uint8_t *buffer, int32_t buflen)
 144 {
 145     char *hb;
 146     int i,j,l;
 147
 148     if (buflen==0) return 0;
 149     hb=write_mpstring(a);
 150
 151     l=strlen(hb);
 152     i=0; j=0;
 153     if (l&1) {
 154         /* The number starts with a half-byte */
 155         buffer[i++]=hexval(hb[j++]);
 156     }
 157     for (; hb[j] && i<buflen; i++) {
 158         buffer[i]=(hexval(hb[j])<<4)|hexval(hb[j+1]);
 159         j+=2;
 160     }
 161     free(hb);
 162     return i;
 163 }
 164
 165 static const char *phases[NR_PHASES]={
 166     "PHASE_INIT",
 167     "PHASE_GETOPTS",
 168     "PHASE_READCONFIG",
 169     "PHASE_SETUP",
 170     "PHASE_DAEMONIZE",
 171     "PHASE_GETRESOURCES",
 172     "PHASE_DROPPRIV",
 173     "PHASE_RUN",
 174     "PHASE_SHUTDOWN"
 175 };
 176
 177 void enter_phase(uint32_t new_phase)
 178 {
 179     struct phase_hook *i;
 180
 181     if (hooks[new_phase])
 182         Message(M_DEBUG_PHASE,"Running hooks for %s...\n", phases[new_phase]);
 183     current_phase=new_phase;
 184
 185     for (i=hooks[new_phase]; i; i=i->next)
 186         i->fn(i->state, new_phase);
 187     Message(M_DEBUG_PHASE,"Now in %s\n",phases[new_phase]);
 188 }
 189
 190 bool_t add_hook(uint32_t phase, hook_fn *fn, void *state)
 191 {
 192     struct phase_hook *h;
 193
 194     h=safe_malloc(sizeof(*h),"add_hook");
 195     h->fn=fn;
 196     h->state=state;
 197     h->next=hooks[phase];
 198     hooks[phase]=h;
 199     return True;
 200 }
 201
 202 bool_t remove_hook(uint32_t phase, hook_fn *fn, void *state)
 203 {
 204     fatal("remove_hook: not implemented");
 205
 206     return False;
 207 }
 208
 209 void vslilog(struct log_if *lf, int priority, const char *message, va_list ap)
 210 {
 211     lf->vlog(lf->st,priority,message,ap);
 212 }
 213
 214 void slilog(struct log_if *lf, int priority, const char *message, ...)
 215 {
 216     va_list ap;
 217
 218     va_start(ap,message);
 219     vslilog(lf,priority,message,ap);
 220     va_end(ap);
 221 }
 222
 223 struct buffer {
 224     closure_t cl;
 225     struct buffer_if ops;
 226 };
 227
 228 void buffer_assert_free(struct buffer_if *buffer, cstring_t file,
 229                         int line)
 230 {
 231     if (!buffer->free) {
 232         fprintf(stderr,"secnet: BUF_ASSERT_FREE, %s line %d, owned by %s",
 233                 file,line,buffer->owner);
 234         assert(!"buffer_assert_free failure");
 235     }
 236 }
 237
 238 void buffer_assert_used(struct buffer_if *buffer, cstring_t file,
 239                         int line)
 240 {
 241     if (buffer->free) {
 242         fprintf(stderr,"secnet: BUF_ASSERT_USED, %s line %d, last owned by %s",
 243                 file,line,buffer->owner);
 244         assert(!"buffer_assert_used failure");
 245     }
 246 }
 247
 248 void buffer_init(struct buffer_if *buffer, int32_t max_start_pad)
 249 {
 250     buffer->start=buffer->base+max_start_pad;
 251     buffer->size=0;
 252 }
 253
 254 void *buf_append(struct buffer_if *buf, int32_t amount) {
 255     void *p;
 256     assert(buf->size <= buf->len - amount);
 257     p=buf->start + buf->size;
 258     buf->size+=amount;
 259     return p;
 260 }
 261
 262 void *buf_prepend(struct buffer_if *buf, int32_t amount) {
 263     assert(amount <= buf->start - buf->base);
 264     buf->size+=amount;
 265     return buf->start-=amount;
 266 }
 267
 268 void *buf_unappend(struct buffer_if *buf, int32_t amount) {
 269     if (buf->size < amount) return 0;
 270     return buf->start+(buf->size-=amount);
 271 }
 272
 273 void *buf_unprepend(struct buffer_if *buf, int32_t amount) {
 274     void *p;
 275     if (buf->size < amount) return 0;
 276     p=buf->start;
 277     buf->start+=amount;
 278     buf->size-=amount;
 279     return p;
 280 }
 281
 282 /* Append a two-byte length and the string to the buffer. Length is in
 283    network byte order. */
 284 void buf_append_string(struct buffer_if *buf, cstring_t s)
 285 {
 286     size_t len;
 287
 288     len=strlen(s);
 289     /* fixme: if string is longer than 65535, result is a corrupted packet */
 290     buf_append_uint16(buf,len);
 291     memcpy(buf_append(buf,len),s,len);
 292 }
 293
 294 void buffer_new(struct buffer_if *buf, int32_t len)
 295 {
 296     buf->free=True;
 297     buf->owner=NULL;
 298     buf->flags=0;
 299     buf->loc.file=NULL;
 300     buf->loc.line=0;
 301     buf->size=0;
 302     buf->len=len;
 303     buf->start=NULL;
 304     buf->base=safe_malloc(len,"buffer_new");
 305 }
 306
 307 void buffer_readonly_view(struct buffer_if *buf, const void *data, int32_t len)
 308 {
 309     buf->free=False;
 310     buf->owner="READONLY";
 311     buf->flags=0;
 312     buf->loc.file=NULL;
 313     buf->loc.line=0;
 314     buf->size=buf->len=len;
 315     buf->base=buf->start=(uint8_t*)data;
 316 }
 317
 318 void buffer_readonly_clone(struct buffer_if *out, const struct buffer_if *in)
 319 {
 320     buffer_readonly_view(out,in->start,in->size);
 321 }
 322
 323 void buffer_copy(struct buffer_if *dst, const struct buffer_if *src)
 324 {
 325     if (dst->len < src->len) {
 326         dst->base=realloc(dst->base,src->len);
 327         if (!dst->base) fatal_perror("buffer_copy");
 328         dst->len = src->len;
 329     }
 330     dst->start = dst->base + (src->start - src->base);
 331     dst->size = src->size;
 332     memcpy(dst->start, src->start, dst->size);
 333 }
 334
 335 static list_t *buffer_apply(closure_t *self, struct cloc loc, dict_t *context,
 336                             list_t *args)
 337 {
 338     struct buffer *st;
 339     item_t *item;
 340     dict_t *dict;
 341     bool_t lockdown=False;
 342     uint32_t len=DEFAULT_BUFFER_SIZE;
 343
 344     st=safe_malloc(sizeof(*st),"buffer_apply");
 345     st->cl.description="buffer";
 346     st->cl.type=CL_BUFFER;
 347     st->cl.apply=NULL;
 348     st->cl.interface=&st->ops;
 349
 350     /* First argument, if present, is buffer length */
 351     item=list_elem(args,0);
 352     if (item) {
 353         if (item->type!=t_number) {
 354             cfgfatal(st->ops.loc,"buffer","first parameter must be a "
 355                      "number (buffer size)\n");
 356         }
 357         len=item->data.number;
 358         if (len<MIN_BUFFER_SIZE) {
 359             cfgfatal(st->ops.loc,"buffer","ludicrously small buffer size\n");
 360         }
 361         if (len>MAX_BUFFER_SIZE) {
 362             cfgfatal(st->ops.loc,"buffer","ludicrously large buffer size\n");
 363         }
 364     }
 365     /* Second argument, if present, is a dictionary */
 366     item=list_elem(args,1);
 367     if (item) {
 368         if (item->type!=t_dict) {
 369             cfgfatal(st->ops.loc,"buffer","second parameter must be a "
 370                      "dictionary\n");
 371         }
 372         dict=item->data.dict;
 373         lockdown=dict_read_bool(dict,"lockdown",False,"buffer",st->ops.loc,
 374                                 False);
 375     }
 376
 377     buffer_new(&st->ops,len);
 378     if (lockdown) {
 379         /* XXX mlock the buffer if possible */
 380     }
 381
 382     return new_closure(&st->cl);
 383 }
 384
 385 void send_nak(const struct comm_addr *dest, uint32_t our_index,
 386               uint32_t their_index, uint32_t msgtype,
 387               struct buffer_if *buf, const char *logwhy)
 388 {
 389     buffer_init(buf,dest->comm->min_start_pad);
 390     buf_append_uint32(buf,their_index);
 391     buf_append_uint32(buf,our_index);
 392     buf_append_uint32(buf,LABEL_NAK);
 393     if (logwhy)
 394         Message(M_INFO,"%s: %08"PRIx32"<-%08"PRIx32": %08"PRIx32":"
 395                 " %s; sending NAK\n",
 396                 dest->comm->addr_to_string(dest->comm->st,dest),
 397                 our_index, their_index, msgtype, logwhy);
 398     dest->comm->sendmsg(dest->comm->st, buf, dest);
 399 }
 400
 401 int consttime_memeq(const void *s1in, const void *s2in, size_t n)
 402 {
 403     const uint8_t *s1=s1in, *s2=s2in;
 404     register volatile uint8_t accumulator=0;
 405
 406     while (n-- > 0) {
 407         accumulator |= (*s1++ ^ *s2++);
 408     }
 409     accumulator |= accumulator >> 4; /* constant-time             */
 410     accumulator |= accumulator >> 2; /*  boolean canonicalisation */
 411     accumulator |= accumulator >> 1;
 412     accumulator &= 1;
 413     accumulator ^= 1;
 414     return accumulator;
 415 }
 416
 417 void util_module(dict_t *dict)
 418 {
 419     add_closure(dict,"sysbuffer",buffer_apply);
 420 }