addrcheck: Optionally invoke userv service to decide address validity.

It may be that the existence of a mailbox can be best determined
programmatically, rather than by the existence of a .qmail-BLAH file for
it.  For example, imagine a remailer which uses encrypted email
addresses: it'd be better to check the authentication on an address than
to have a .qmail file for each one.

If a user's .qmail-FOO-default file has a first line of the form
`#?ANYTHING then that user's userv service `addrcheck:USER-FOO-default'
is invoked, with these arguments:

  * the remainder of the destination email address (including the domain
    part);

  * the envelope sender (which may be useful);

  * the entire destination email address; and

  * the key `USER-FOO-default' which the address matched.

The service should output a `+' or `-' sign to indicate acceptance or
rejection.  Failure to do this, or exiting with a nonzero status, causes
a temporary error to be reported to the SMTP client.

diff --git a/addrcheck.c b/addrcheck.c
index 2ff9d13..08d29b9 100644 (file)
--- a/addrcheck.c
+++ b/addrcheck.c
@@ -4,13 +4,13 @@
 #include "str.h"
 #include "addrcheck.h"
 #include <errno.h>
+#include <unistd.h>
 
 /* #define DEBUG */
 #ifdef DEBUG
 #  define D(x) x
 #  include <stdio.h>
 #  include <sys/types.h>
-#  include <unistd.h>
 #else
 #  define D(x)
 #endif
@@ -18,7 +18,7 @@
 #define STRALLOC_INIT { 0 }
 
 static int probe(int cdb, int prefix, const char *key, int len,
-                const char *suffix, uint32 *dlen)
+                const char *suffix, const char **kp, uint32 *dlen)
 {
   static stralloc k = STRALLOC_INIT;
   char ch = prefix;
@@ -27,10 +27,12 @@ static int probe(int cdb, int prefix, const char *key, int len,
   k.len = 0;
   if (!stralloc_append(&k, &ch) ||
       !stralloc_catb(&k, key, len) ||
-      (suffix && !stralloc_cats(&k, suffix)))
+      (suffix && !stralloc_cats(&k, suffix)) ||
+      !stralloc_0(&k))
     return (-1);
+  if (kp) *kp = k.s;
   D( fprintf(stderr, "*** `%.*s' -> ", k.len, k.s); )
-  rc = cdb_seek(cdb, k.s, k.len, dlen);
+  rc = cdb_seek(cdb, k.s, k.len - 1, dlen);
   D( if (rc == -1)
        fprintf(stderr, "error: %s\n", strerror(errno));
      else if (rc == 0)
@@ -55,34 +57,86 @@ static int probe(int cdb, int prefix, const char *key, int len,
   return (rc);
 }
 
-static int localprobe(int cdb, const char *key, int len,
-                     const char *suffix, int *rc)
+static int localprobe(int cdb, const char *sender,
+                     const char *key, int len,
+                     const char *suffix, const char *tail, int *rc)
 {
   int err;
   uint32 dlen;
   char ch;
-
-  if ((err = probe(cdb, 'L', key, len, suffix, &dlen)) < 0)
+  const char *k;
+  static stralloc u =  STRALLOC_INIT;
+  static stralloc serv = STRALLOC_INIT;
+  int kid;
+  int n;
+  int wstat;
+  int p[2];
+
+  if ((err = probe(cdb, 'L', key, len, suffix, &k, &dlen)) < 0)
     return (-1);
   if (!err) { *rc = 0; return (0); }
-  if (dlen != 1) { errno = EINVAL; return (-1); }
+  if (!dlen) { errno = EINVAL; return (-1); }  
   if (read(cdb, &ch, 1) != 1) { errno = EIO; return (-1); }
+  if (ch == '?') {
+    u.len = 0;
+    if (!stralloc_ready(&u, dlen - 1)) return (-1);
+    if (read(cdb, u.s, dlen - 1) != dlen - 1) { errno = EIO; return (-1); }
+    u.len = dlen - 1;
+    serv.len = 0;
+    if (!stralloc_cats(&serv, "addrcheck:") ||
+       !stralloc_cats(&serv, k + 1) ||
+       !stralloc_0(&serv) ||
+       !stralloc_0(&u))
+      return (-1);
+    D( fprintf(stderr, "asking user:\n\
+  user = %s; service = %s\n  tail = %s; sender = %s\n\
+  address = %s; key = %s\n",
+              u.s, serv.s, tail, sender, key, k + 1); )
+              
+    if (pipe(p) || (kid = fork()) == -1)
+      return (-1);
+    if (!kid) {
+      dup2(p[1], 1);
+      close(p[0]);
+      close(p[1]);
+      execl("/usr/bin/userv", "/usr/bin/userv",
+           "-f", "stdin=/dev/null",
+           u.s, serv.s,
+           tail, sender, key, k + 1,
+           (char *)0);
+      _exit(127);
+    }
+    close(p[1]);
+    n = read(p[0], &ch, 1);
+    close(p[0]);
+    if (wait_pid(&wstat, kid) < 0) { return (-1); }
+    D( fprintf(stderr, "userv exited with status %d\n", wstat); )
+    if (n != 1 || wstat) { errno = EAGAIN; return (-1); }
+    D( fprintf(stderr, "userv answer was `%c'\n", ch); )
+  } else if (dlen != 1) {
+    errno = EIO;
+    return (-1);
+  }
   *rc = ch;
   return (1);
 }
 
-static int local(int cdb, const char *l, int len, int *rc)
+static int local(int cdb, const char *l, int len,
+                const char *sender, int *rc)
 {
   int code;
   int err = 0;
   int dash;
 
-  if ((err = localprobe(cdb, l, len, 0, &code)) != 0) goto done;
+  if ((err = localprobe(cdb, sender, l, len, 0, l + len, &code)) != 0)
+    goto done;
 
   for (;;) {
     dash = byte_rchr(l, len, '-');
     if (dash == len) break;
-    if ((err = localprobe(cdb, l, dash, "-default", &code)) != 0) goto done;
+    if ((err = localprobe(cdb, sender,
+                         l, dash, "-default", l + dash + 1, &code)) != 0)
+      goto done;
     len = dash;
   }
   *rc = 0;
@@ -100,25 +154,25 @@ done:
 }
 
 static int virt(int cdb, const char *u, int ulen,
-               const char *addr, int alen, int *rc)
+               const char *addr, int alen, const char *sender, int *rc)
 {
   static stralloc l = STRALLOC_INIT;
   uint32 dlen;
   int err;
 
-  if ((err = probe(cdb, 'V', addr, alen, 0, &dlen)) <= 0)
+  if ((err = probe(cdb, 'V', addr, alen, 0, 0, &dlen)) <= 0)
     return (err);
   if (!stralloc_ready(&l, dlen + 1)) return (-1);
   if (read(cdb, l.s, dlen) != dlen) { errno = EIO; return (-1); }
   l.s[dlen] = '-';
   l.len = dlen + 1;
-  if (!stralloc_catb(&l, u, ulen)) return (-1);
-  D( printf("*** virtual map -> `%.*s'\n", l.len, l.s); )
-  if (local(cdb, l.s, l.len, rc) < 0) return (-1);
+  if (!stralloc_catb(&l, u, ulen) || !stralloc_0(&l)) return (-1);
+  D( printf("*** virtual map -> `%s'\n", l.s); )
+  if (local(cdb, l.s, l.len - 1, sender, rc) < 0) return (-1);
   return (1);
 }
 
-int addrcheck(int cdb, const char *addr, int *rc)
+int addrcheck(int cdb, const char *addr, const char *sender, int *rc)
 {
   int at, len, dot;
   int err = 0;
@@ -127,26 +181,27 @@ int addrcheck(int cdb, const char *addr, int *rc)
   len = str_len(addr);
   at = str_chr(addr, '@');
   if (!addr[at])
-    return (local(cdb, addr, len, rc));
+    return (local(cdb, addr, len, sender, rc));
 
-  if ((err = virt(cdb, addr, at, addr, len, rc)) != 0)
+  if ((err = virt(cdb, addr, at, addr, len, sender, rc)) != 0)
     return (err);
   dot = at + 1;
   while (addr[dot]) {
-    if ((err = virt(cdb, addr, at, addr + dot, len - dot, rc)) != 0)
+    if ((err = virt(cdb, addr, at, addr + dot, len - dot, sender, rc)) != 0)
       return (err);
     dot += byte_chr(addr + dot + 1, len - dot - 1, '.') + 1;
   }
 
-  if ((err = probe(cdb, '@', addr + at + 1, len - at - 1, 0, &dlen)) < 0)
+  if ((err = probe(cdb, '@', addr + at + 1, len - at - 1, 0, 0, &dlen)) < 0)
     return (-1);
   if (!err) { *rc = 1; return (0); }
   if (dlen != 0) { errno = EINVAL; return (-1); }
 
-  return (local(cdb, addr, at, rc));
+  return (local(cdb, addr, at, sender, rc));
 }
 
 #ifdef TEST
+
 #include <sys/types.h>
 #include <unistd.h>
 #include <fcntl.h>
@@ -160,16 +215,16 @@ int main(int argc, char *argv[])
   int rc;
   int i;
 
-  if (argc < 3) {
-    fprintf(stderr, "usage: addrcheck CDB ADDR...\n");
+  if (argc < 4) {
+    fprintf(stderr, "usage: addrcheck CDB SENDER ADDR...\n");
     return (1);
   }
   if ((fd = open(argv[1], O_RDONLY)) < 0) {
     perror(argv[1]);
     return (1);
   }
-  for (i = 2; i < argc; i++) {
-    if (addrcheck(fd, argv[i], &rc) < 0) {
+  for (i = 3; i < argc; i++) {
+    if (addrcheck(fd, argv[i], argv[2], &rc) < 0) {
       perror("checking");
       return (1);
     }

diff --git a/addrcheck.h b/addrcheck.h
index 7c51909..b4bc555 100644 (file)
--- a/addrcheck.h
+++ b/addrcheck.h
@@ -1,6 +1,6 @@
 #ifndef ADDRCHECK_H
 #define ADDRCHECK_H
 
-extern int addrcheck(int, const char *, int *);
+extern int addrcheck(int, const char *, const char *, int *);
 
 #endif

diff --git a/qmail-smtpd.c b/qmail-smtpd.c
index 82ac46a..d2ad504 100644 (file)
--- a/qmail-smtpd.c
+++ b/qmail-smtpd.c
@@ -300,7 +300,7 @@ void smtp_rcpt(arg) char *arg; {
     if (!addrallowed()) { err_nogateway(); return; }
   if (ac_fd != -1) {
     int rc;
-    if (addrcheck(ac_fd, addr.s, &rc) < 0) {
+    if (addrcheck(ac_fd, addr.s, mailfrom.s, &rc) < 0) {
       if (errno == error_nomem)
        die_nomem();
       else

diff --git a/qmail-valid-addresses b/qmail-valid-addresses
index 9821394..d43cf85 100644 (file)
--- a/qmail-valid-addresses
+++ b/qmail-valid-addresses
@@ -41,7 +41,7 @@ for k in udb.keys():
 del udb
 
 map = {}
-def addlocal(p, l, forcep = False):
+def addlocal(u, p, l, forcep = False):
   l = 'L' + l
   if not os.path.exists(p):
     if forcep:
@@ -50,8 +50,13 @@ def addlocal(p, l, forcep = False):
   f = open(p)
   top = f.readline()
   f.close()
-  if len(top) > 0 and top[0] == '!':
+  if len(top) > 1 and top[0:2] == '#!':
     map[l] = '-'
+  elif len(top) > 1 and top[0:2] == '#?':
+    name = u.name
+    if name[-1] == '-':
+      name = name[:-1]
+    map[l] = '?' + name
   else:
     map[l] = '+'
 for k in sort(umap.keys()):
@@ -63,9 +68,9 @@ for k in sort(umap.keys()):
       if not p.startswith(qm):
         continue
       ext = p[qmlen:]
-      addlocal(os.path.join(u.home, p), u.name + ext)
+      addlocal(u, os.path.join(u.home, p), u.name + ext)
   else:
-    addlocal(os.path.join(u.home, qm), u.name, u.dash == '')
+    addlocal(u, os.path.join(u.home, qm), u.name, u.dash == '')
 
 me = open('control/me').readline()