mdw@git.distorted.org.uk Git - qmail/blob - addrcheck.c

   1 #include "cdb.h"
   2 #include "stralloc.h"
   3 #include "byte.h"
   4 #include "str.h"
   5 #include "addrcheck.h"
   6 #include <errno.h>
   7 #include <unistd.h>
   8 #include <fcntl.h>
   9
  10 /* #define DEBUG */
  11 #ifdef DEBUG
  12 #  define D(x) x
  13 #  include <stdio.h>
  14 #  include <sys/types.h>
  15 #else
  16 #  define D(x)
  17 #endif
  18
  19 #define STRALLOC_INIT { 0 }
  20
  21 /* --- @probe@ --- *
  22  *
  23  * Arguments:   @int cdb@ = the CDB file descriptor
  24  *              @int prefix@ = the prefix character (e.g., @'V'@)
  25  *              @const char *key, int len@ = the key string and its length
  26  *              @const char *suffix@ = a suffix to append to the key
  27  *              @const char **kp@ = where to put the full key string
  28  *              @uint32 *dlen@ = where to put the answer's length
  29  *
  30  * Returns:     Zero if the lookup failed, @+1@ on success, or @-1@ for an
  31  *              error.
  32  *
  33  * Use:         Probes a CDB file.  The key looked up is the character
  34  *              @prefix@ followed by the first @len@ bytes of @key@, followed
  35  *              by @suffix@ (if non-null).
  36  */
  37
  38 static int probe(int cdb, int prefix, const char *key, int len,
  39                  const char *suffix, const char **kp, uint32 *dlen)
  40 {
  41   static stralloc k = STRALLOC_INIT;
  42   char ch = prefix;
  43   int rc;
  44
  45   k.len = 0;
  46   if (!stralloc_append(&k, &ch) ||
  47       !stralloc_catb(&k, key, len) ||
  48       (suffix && !stralloc_cats(&k, suffix)) ||
  49       !stralloc_0(&k))
  50     return (-1);
  51   if (kp) *kp = k.s;
  52   D( fprintf(stderr, "*** `%.*s' -> ", k.len, k.s); )
  53   rc = cdb_seek(cdb, k.s, k.len - 1, dlen);
  54   D( if (rc == -1)
  55        fprintf(stderr, "error: %s\n", strerror(errno));
  56      else if (rc == 0)
  57        fprintf(stderr, "not found\n");
  58      else if (!*dlen)
  59        fprintf(stderr, "empty\n");
  60      else {
  61        int n = *dlen;
  62        int nn;
  63        char buf[256];
  64        off_t pos = lseek(cdb, 0, SEEK_CUR);
  65        fprintf(stderr, "`");
  66        while (n) {
  67          nn = sizeof(buf); if (nn > n) nn = n;
  68          read(cdb, buf, nn);
  69          fwrite(buf, 1, nn, stderr);
  70          n -= nn;
  71        }
  72        fprintf(stderr, "'\n");
  73        lseek(cdb, pos, SEEK_SET);
  74      } )
  75   return (rc);
  76 }
  77
  78 /* --- @localprobe@ --- *
  79  *
  80  * Arguments:   @int cdb@ = the CDB file descriptor
  81  *              @const char *sender@ = the envelope-sender address
  82  *              @const char *key, int len@ = the (possibly defaulted) mailbox
  83  *                      name to look up
  84  *              @const char *suffix@ = a suffix to append to the key (e.g.,
  85  *                      @"-default"@)
  86  *              @const char *tail@ = the tail of the local address matching
  87  *                      any defaulted extension part
  88  *              @int *rc@ = where to put the answer
  89  *
  90  * Returns:     Positive if found, zero if not found, negative on error.
  91  *
  92  * Use:         Looks up a local-part in the database.  This may involve
  93  *              invoking a Userv service for the recipient's owner.
  94  */
  95
  96 static int localprobe(int cdb, const char *sender,
  97                       const char *key, int len,
  98                       const char *suffix, const char *tail, int *rc)
  99 {
 100   int err;
 101   uint32 dlen;
 102   char ch;
 103   const char *k;
 104   static stralloc u =  STRALLOC_INIT;
 105   static stralloc serv = STRALLOC_INIT;
 106   int kid;
 107   int n;
 108   int wstat;
 109   int p[2];
 110
 111   if ((err = probe(cdb, 'L', key, len, suffix, &k, &dlen)) < 0)
 112     return (-1);
 113   if (!err) { *rc = 0; return (0); }
 114   if (!dlen) { errno = EINVAL; return (-1); }
 115   if (read(cdb, &ch, 1) != 1) { errno = EIO; return (-1); }
 116   if (ch == '?') {
 117     u.len = 0;
 118     if (!stralloc_ready(&u, dlen - 1)) return (-1);
 119     if (read(cdb, u.s, dlen - 1) != dlen - 1) { errno = EIO; return (-1); }
 120     u.len = dlen - 1;
 121     serv.len = 0;
 122     if (!stralloc_cats(&serv, "addrcheck:") ||
 123         !stralloc_cats(&serv, k + 1) ||
 124         !stralloc_0(&serv) ||
 125         !stralloc_0(&u))
 126       return (-1);
 127     D( fprintf(stderr, "asking user:\n\
 128   user = %s; service = %s\n  tail = %s; sender = %s\n\
 129   address = %s; key = %s\n",
 130                u.s, serv.s, tail, sender, key, k + 1); )
 131
 132     if (pipe(p) || (kid = fork()) == -1)
 133       return (-1);
 134     if (!kid) {
 135       close(0); open("/dev/null", O_RDONLY);
 136       dup2(p[1], 1);
 137       close(2); open("/dev/null", O_WRONLY);
 138       close(p[0]); close(p[1]);
 139       execl("/usr/bin/userv", "/usr/bin/userv",
 140             "-f", "stdin=/dev/null",
 141             u.s, serv.s,
 142             tail, sender, key, k + 1,
 143             (char *)0);
 144       _exit(127);
 145     }
 146     close(p[1]);
 147     n = read(p[0], &ch, 1);
 148     close(p[0]);
 149     if (wait_pid(&wstat, kid) < 0) { return (-1); }
 150     D( fprintf(stderr, "userv exited with status %d\n", wstat); )
 151     if (n != 1 || wstat) { errno = EAGAIN; return (-1); }
 152     D( fprintf(stderr, "userv answer was `%c'\n", ch); )
 153   } else if (dlen != 1) {
 154     errno = EIO;
 155     return (-1);
 156   }
 157   *rc = ch;
 158   return (1);
 159 }
 160
 161 /* --- @local@ --- *
 162  *
 163  * Arguments:   @int cdb@ = file descriptor for the CDB
 164  *              @const char *l@ = pointer to local-part to look up
 165  *              @int len@ = length of the local-part
 166  *              @const char *sender@ = envelope sender address
 167  *              @int *rc@ = where to put the answer
 168  *
 169  * Returns:     Positive if answered, zero if lookup failed, negative on
 170  *              error.
 171  *
 172  * Use:         Finds out whether @l@ is a valid local-part for a non-virtual
 173  *              mailbox name.  Handles defaulting of extension addresses and
 174  *              suchlike.
 175  */
 176
 177 static int local(int cdb, const char *l, int len,
 178                  const char *sender, int *rc)
 179 {
 180   int code;
 181   int err = 0;
 182   int dash;
 183
 184   if ((err = localprobe(cdb, sender, l, len, 0, l + len, &code)) != 0)
 185     goto done;
 186
 187   for (;;) {
 188     dash = byte_rchr(l, len, '-');
 189     if (dash == len) break;
 190     if ((err = localprobe(cdb, sender,
 191                           l, dash, "-default", l + dash + 1, &code)) != 0)
 192       goto done;
 193     len = dash;
 194   }
 195   *rc = 0;
 196   return (0);
 197
 198 done:
 199   if (err >= 0) {
 200     switch (code) {
 201       case '+': *rc = 1; break;
 202       case '-': *rc = 0; break;
 203       default: errno = EINVAL; err = -1; break;
 204     }
 205   }
 206   return (err);
 207 }
 208
 209 /* --- @virt@ --- *
 210  *
 211  * Arguments:   @int cdb@ = file descriptor for CDB
 212  *              @const char *u@ = the local-part of the recipient mailbox
 213  *              @int ulen@ = length of the local-part
 214  *              @const char *addr@ = the virtual domain to look up
 215  *              @int alen@ = length of the virtual domain
 216  *              @const char *sender@ = the envelope sender address
 217  *              @int *rc@ = where to put the answer
 218  *
 219  * Returns:     Positive if found, zero if not found, negative on error.
 220  *
 221  * Use:         Looks up the address as a virtual domain.  If found, the
 222  *              local-part is appended to the local mailbox handling the
 223  *              virtual domain and passed to @local@.
 224  */
 225
 226 static int virt(int cdb, const char *u, int ulen,
 227                 const char *addr, int alen, const char *sender, int *rc)
 228 {
 229   static stralloc l = STRALLOC_INIT;
 230   uint32 dlen;
 231   int err;
 232
 233   if ((err = probe(cdb, 'V', addr, alen, 0, 0, &dlen)) <= 0)
 234     return (err);
 235   if (!stralloc_ready(&l, dlen + 1)) return (-1);
 236   if (read(cdb, l.s, dlen) != dlen) { errno = EIO; return (-1); }
 237   l.s[dlen] = '-';
 238   l.len = dlen + 1;
 239   if (!stralloc_catb(&l, u, ulen) || !stralloc_0(&l)) return (-1);
 240   D( printf("*** virtual map -> `%s'\n", l.s); )
 241   if (local(cdb, l.s, l.len - 1, sender, rc) < 0) return (-1);
 242   return (1);
 243 }
 244
 245 /* --- @addrcheck@ --- *
 246  *
 247  * Arguments:   @int cdb@ = file descriptor for CDB to look things up in
 248  *              @const char *addr@ = the (full) recipient mailbox to look up
 249  *              @const char *sender@ = the (full) envelope sender address
 250  *              @int *rc@ = where to put the answer.
 251  *
 252  * Returns:     Nonnegative on success, or @-1@ on failure.
 253  *
 254  * Use:         Determines whether @addr@ is a valid mailbox on this system,
 255  *              by examining the given CDB file.  On exit, @*rc@ is set to
 256  *              @'+'@ if the mailbox is valid, or @'-'@ if not.
 257  */
 258
 259 int addrcheck(int cdb, const char *addr, const char *sender, int *rc)
 260 {
 261   int at, len, dot;
 262   int err = 0;
 263   uint32 dlen;
 264   static stralloc l = STRALLOC_INIT;
 265
 266   len = str_len(addr);
 267   at = str_chr(addr, '@');
 268   if (!addr[at])
 269     return (local(cdb, addr, len, sender, rc));
 270
 271   if ((err = virt(cdb, addr, at, addr, len, sender, rc)) != 0)
 272     return (err);
 273   dot = at + 1;
 274   while (addr[dot]) {
 275     if ((err = virt(cdb, addr, at, addr + dot, len - dot, sender, rc)) != 0)
 276       return (err);
 277     dot += byte_chr(addr + dot + 1, len - dot - 1, '.') + 1;
 278   }
 279
 280   if ((err = probe(cdb, '@', addr + at + 1, len - at - 1, 0, 0, &dlen)) < 0)
 281     return (-1);
 282   if (!err) { *rc = 1; return (0); }
 283   if (dlen != 0) { errno = EINVAL; return (-1); }
 284   l.len = 0;
 285   if (!stralloc_catb(&l, addr, at) ||
 286       !stralloc_0(&l))
 287     return (-1);
 288   return (local(cdb, l.s, l.len - 1, sender, rc));
 289 }
 290
 291 #ifdef TEST
 292
 293 #include <sys/types.h>
 294 #include <unistd.h>
 295 #include <fcntl.h>
 296 #include <stdio.h>
 297 #include <errno.h>
 298 #include <unistd.h>
 299
 300 int main(int argc, char *argv[])
 301 {
 302   int fd;
 303   int rc;
 304   int i;
 305
 306   if (argc < 4) {
 307     fprintf(stderr, "usage: addrcheck CDB SENDER ADDR...\n");
 308     return (1);
 309   }
 310   if ((fd = open(argv[1], O_RDONLY)) < 0) {
 311     perror(argv[1]);
 312     return (1);
 313   }
 314   for (i = 3; i < argc; i++) {
 315     if (addrcheck(fd, argv[i], argv[2], &rc) < 0) {
 316       perror("checking");
 317       return (1);
 318     }
 319     printf("%s: %s\n", argv[i], rc ? "ok" : "bad");
 320   }
 321   return (0);
 322 }
 323
 324 #endif