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