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
  42 #define MIN_BUFFER_SIZE 64
  43 #define DEFAULT_BUFFER_SIZE 4096
  44 #define MAX_BUFFER_SIZE 131072
  45
  46 static const char *hexdigits="0123456789abcdef";
  47
  48 uint32_t current_phase=0;
  49
  50 struct phase_hook {
  51     hook_fn *fn;
  52     void *state;
  53     struct phase_hook *next;
  54 };
  55
  56 static struct phase_hook *hooks[NR_PHASES]={NULL,};
  57
  58 char *safe_strdup(const char *s, const char *message)
  59 {
  60     char *d;
  61     d=strdup(s);
  62     if (!d) {
  63         fatal_perror(message);
  64     }
  65     return d;
  66 }
  67
  68 void *safe_malloc(size_t size, const char *message)
  69 {
  70     void *r;
  71     r=malloc(size);
  72     if (!r) {
  73         fatal_perror(message);
  74     }
  75     return r;
  76 }
  77 void *safe_malloc_ary(size_t size, size_t count, const char *message) {
  78     if (count >= INT_MAX/size) {
  79         fatal("array allocation overflow: %s", message);
  80     }
  81     return safe_malloc(size*count, message);
  82 }
  83
  84 /* Convert a buffer into its MP_INT representation */
  85 void read_mpbin(MP_INT *a, uint8_t *bin, int binsize)
  86 {
  87     char *buff;
  88     int i;
  89
  90     buff=safe_malloc(binsize*2 + 1,"read_mpbin");
  91
  92     for (i=0; i<binsize; i++) {
  93         buff[i*2]=hexdigits[(bin[i] & 0xf0) >> 4];
  94         buff[i*2+1]=hexdigits[(bin[i] & 0xf)];
  95     }
  96     buff[binsize*2]=0;
  97
  98     mpz_set_str(a, buff, 16);
  99     free(buff);
 100 }
 101
 102 /* Convert a MP_INT into a hex string */
 103 char *write_mpstring(MP_INT *a)
 104 {
 105     char *buff;
 106
 107     buff=safe_malloc(mpz_sizeinbase(a,16)+2,"write_mpstring");
 108     mpz_get_str(buff, 16, a);
 109     return buff;
 110 }
 111
 112 static uint8_t hexval(uint8_t c)
 113 {
 114     switch (c) {
 115     case '0': return 0;
 116     case '1': return 1;
 117     case '2': return 2;
 118     case '3': return 3;
 119     case '4': return 4;
 120     case '5': return 5;
 121     case '6': return 6;
 122     case '7': return 7;
 123     case '8': return 8;
 124     case '9': return 9;
 125     case 'a': return 10;
 126     case 'A': return 10;
 127     case 'b': return 11;
 128     case 'B': return 11;
 129     case 'c': return 12;
 130     case 'C': return 12;
 131     case 'd': return 13;
 132     case 'D': return 13;
 133     case 'e': return 14;
 134     case 'E': return 14;
 135     case 'f': return 15;
 136     case 'F': return 15;
 137     }
 138     return -1;
 139 }
 140
 141 /* Convert a MP_INT into a buffer; return length; truncate if necessary */
 142 uint32_t write_mpbin(MP_INT *a, uint8_t *buffer, uint32_t buflen)
 143 {
 144     char *hb;
 145     int i,j,l;
 146
 147     if (buflen==0) return 0;
 148     hb=write_mpstring(a);
 149
 150     l=strlen(hb);
 151     i=0; j=0;
 152     if (l&1) {
 153         /* The number starts with a half-byte */
 154         buffer[i++]=hexval(hb[j++]);
 155     }
 156     for (; hb[j] && i<buflen; i++) {
 157         buffer[i]=(hexval(hb[j])<<4)|hexval(hb[j+1]);
 158         j+=2;
 159     }
 160     free(hb);
 161     return i;
 162 }
 163
 164 static const char *phases[NR_PHASES]={
 165     "PHASE_INIT",
 166     "PHASE_GETOPTS",
 167     "PHASE_READCONFIG",
 168     "PHASE_SETUP",
 169     "PHASE_GETRESOURCES",
 170     "PHASE_DROPPRIV",
 171     "PHASE_RUN",
 172     "PHASE_SHUTDOWN"
 173 };
 174
 175 void enter_phase(uint32_t new_phase)
 176 {
 177     struct phase_hook *i;
 178
 179     if (hooks[new_phase])
 180         Message(M_DEBUG_PHASE,"Running hooks for %s...\n", phases[new_phase]);
 181     current_phase=new_phase;
 182
 183     for (i=hooks[new_phase]; i; i=i->next)
 184         i->fn(i->state, new_phase);
 185     Message(M_DEBUG_PHASE,"Now in %s\n",phases[new_phase]);
 186 }
 187
 188 bool_t add_hook(uint32_t phase, hook_fn *fn, void *state)
 189 {
 190     struct phase_hook *h;
 191
 192     h=safe_malloc(sizeof(*h),"add_hook");
 193     h->fn=fn;
 194     h->state=state;
 195     h->next=hooks[phase];
 196     hooks[phase]=h;
 197     return True;
 198 }
 199
 200 bool_t remove_hook(uint32_t phase, hook_fn *fn, void *state)
 201 {
 202     fatal("remove_hook: not implemented");
 203
 204     return False;
 205 }
 206
 207 void vslilog(struct log_if *lf, int priority, const char *message, va_list ap)
 208 {
 209     lf->vlog(lf->st,priority,message,ap);
 210 }
 211
 212 void slilog(struct log_if *lf, int priority, const char *message, ...)
 213 {
 214     va_list ap;
 215
 216     va_start(ap,message);
 217     vslilog(lf,priority,message,ap);
 218     va_end(ap);
 219 }
 220
 221 struct buffer {
 222     closure_t cl;
 223     struct buffer_if ops;
 224 };
 225
 226 void buffer_assert_free(struct buffer_if *buffer, cstring_t file,
 227                         uint32_t line)
 228 {
 229     if (!buffer->free) {
 230         fatal("BUF_ASSERT_FREE, %s line %d, owned by %s",
 231               file,line,buffer->owner);
 232     }
 233 }
 234
 235 void buffer_assert_used(struct buffer_if *buffer, cstring_t file,
 236                         uint32_t line)
 237 {
 238     if (buffer->free) {
 239         fatal("BUF_ASSERT_USED, %s line %d, last owned by %s",
 240               file,line,buffer->owner);
 241     }
 242 }
 243
 244 void buffer_init(struct buffer_if *buffer, uint32_t max_start_pad)
 245 {
 246     buffer->start=buffer->base+max_start_pad;
 247     buffer->size=0;
 248 }
 249
 250 void *buf_append(struct buffer_if *buf, uint32_t amount) {
 251     void *p;
 252     assert(buf->size <= buf->len - amount);
 253     p=buf->start + buf->size;
 254     buf->size+=amount;
 255     return p;
 256 }
 257
 258 void *buf_prepend(struct buffer_if *buf, uint32_t amount) {
 259     assert(amount <= buf->start - buf->base);
 260     buf->size+=amount;
 261     return buf->start-=amount;
 262 }
 263
 264 void *buf_unappend(struct buffer_if *buf, uint32_t amount) {
 265     if (buf->size < amount) return 0;
 266     return buf->start+(buf->size-=amount);
 267 }
 268
 269 void *buf_unprepend(struct buffer_if *buf, uint32_t amount) {
 270     void *p;
 271     p=buf->start;
 272     buf->start+=amount;
 273     buf->size-=amount;
 274     return p;
 275 }
 276
 277 /* Append a two-byte length and the string to the buffer. Length is in
 278    network byte order. */
 279 void buf_append_string(struct buffer_if *buf, cstring_t s)
 280 {
 281     uint16_t len;
 282
 283     len=strlen(s);
 284     /* fixme: if string is longer than 65535, result is a corrupted packet */
 285     buf_append_uint16(buf,len);
 286     memcpy(buf_append(buf,len),s,len);
 287 }
 288
 289 void buffer_new(struct buffer_if *buf, uint32_t len)
 290 {
 291     buf->free=True;
 292     buf->owner=NULL;
 293     buf->flags=0;
 294     buf->loc.file=NULL;
 295     buf->loc.line=0;
 296     buf->size=0;
 297     buf->len=len;
 298     buf->start=NULL;
 299     buf->base=safe_malloc(len,"buffer_new");
 300 }
 301
 302 static list_t *buffer_apply(closure_t *self, struct cloc loc, dict_t *context,
 303                             list_t *args)
 304 {
 305     struct buffer *st;
 306     item_t *item;
 307     dict_t *dict;
 308     bool_t lockdown=False;
 309     uint32_t len=DEFAULT_BUFFER_SIZE;
 310
 311     st=safe_malloc(sizeof(*st),"buffer_apply");
 312     st->cl.description="buffer";
 313     st->cl.type=CL_BUFFER;
 314     st->cl.apply=NULL;
 315     st->cl.interface=&st->ops;
 316
 317     /* First argument, if present, is buffer length */
 318     item=list_elem(args,0);
 319     if (item) {
 320         if (item->type!=t_number) {
 321             cfgfatal(st->ops.loc,"buffer","first parameter must be a "
 322                      "number (buffer size)\n");
 323         }
 324         len=item->data.number;
 325         if (len<MIN_BUFFER_SIZE) {
 326             cfgfatal(st->ops.loc,"buffer","ludicrously small buffer size\n");
 327         }
 328         if (len>MAX_BUFFER_SIZE) {
 329             cfgfatal(st->ops.loc,"buffer","ludicrously large buffer size\n");
 330         }
 331     }
 332     /* Second argument, if present, is a dictionary */
 333     item=list_elem(args,1);
 334     if (item) {
 335         if (item->type!=t_dict) {
 336             cfgfatal(st->ops.loc,"buffer","second parameter must be a "
 337                      "dictionary\n");
 338         }
 339         dict=item->data.dict;
 340         lockdown=dict_read_bool(dict,"lockdown",False,"buffer",st->ops.loc,
 341                                 False);
 342     }
 343
 344     buffer_new(&st->ops,len);
 345     if (lockdown) {
 346         /* XXX mlock the buffer if possible */
 347     }
 348
 349     return new_closure(&st->cl);
 350 }
 351
 352 void util_module(dict_t *dict)
 353 {
 354     add_closure(dict,"sysbuffer",buffer_apply);
 355 }