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mbdb.c

/*
 * Copyright (c) 2001-2002 Sendmail, Inc. and its suppliers.
 *      All rights reserved.
 *
 * By using this file, you agree to the terms and conditions set
 * forth in the LICENSE file which can be found at the top level of
 * the sendmail distribution.
 */

#include <sm/gen.h>
SM_RCSID("@(#)$Id: mbdb.c,v 1.40 2003/12/10 03:19:07 gshapiro Exp $")

#include <sys/param.h>

#include <ctype.h>
#include <errno.h>
#include <pwd.h>
#include <stdlib.h>
#include <setjmp.h>
#include <unistd.h>

#include <sm/limits.h>
#include <sm/conf.h>
#include <sm/assert.h>
#include <sm/bitops.h>
#include <sm/errstring.h>
#include <sm/heap.h>
#include <sm/mbdb.h>
#include <sm/string.h>
#ifndef WIN32
# ifdef EX_OK
#  undef EX_OK                /* for SVr4.2 SMP */
# endif /* EX_OK */
#endif /* ! WIN32 */
#include <sm/sysexits.h>

#if LDAPMAP
# if _LDAP_EXAMPLE_
#  include <sm/ldap.h>
# endif /* _LDAP_EXAMPLE_ */
#endif /* LDAPMAP */

typedef struct
{
      char  *mbdb_typename;
      int   (*mbdb_initialize) __P((char *));
      int   (*mbdb_lookup) __P((char *name, SM_MBDB_T *user));
      void  (*mbdb_terminate) __P((void));
} SM_MBDB_TYPE_T;

static int  mbdb_pw_initialize __P((char *));
static int  mbdb_pw_lookup __P((char *name, SM_MBDB_T *user));
static void mbdb_pw_terminate __P((void));

#if LDAPMAP
# if _LDAP_EXAMPLE_
static struct sm_ldap_struct LDAPLMAP;
static int  mbdb_ldap_initialize __P((char *));
static int  mbdb_ldap_lookup __P((char *name, SM_MBDB_T *user));
static void mbdb_ldap_terminate __P((void));
# endif /* _LDAP_EXAMPLE_ */
#endif /* LDAPMAP */

static SM_MBDB_TYPE_T SmMbdbTypes[] =
{
      { "pw", mbdb_pw_initialize, mbdb_pw_lookup, mbdb_pw_terminate },
#if LDAPMAP
# if _LDAP_EXAMPLE_
      { "ldap", mbdb_ldap_initialize, mbdb_ldap_lookup, mbdb_ldap_terminate },
# endif /* _LDAP_EXAMPLE_ */
#endif /* LDAPMAP */
      { NULL, NULL, NULL, NULL }
};

static SM_MBDB_TYPE_T *SmMbdbType = &SmMbdbTypes[0];

/*
**  SM_MBDB_INITIALIZE -- specify which mailbox database to use
**
**    If this function is not called, then the "pw" implementation
**    is used by default; this implementation uses getpwnam().
**
**    Parameters:
**          mbdb -- Which mailbox database to use.
**                The argument has the form "name" or "name.arg".
**                "pw" means use getpwnam().
**
**    Results:
**          EX_OK on success, or an EX_* code on failure.
*/

int
sm_mbdb_initialize(mbdb)
      char *mbdb;
{
      size_t namelen;
      int err;
      char *name;
      char *arg;
      SM_MBDB_TYPE_T *t;

      SM_REQUIRE(mbdb != NULL);

      name = mbdb;
      arg = strchr(mbdb, '.');
      if (arg == NULL)
            namelen = strlen(name);
      else
      {
            namelen = arg - name;
            ++arg;
      }

      for (t = SmMbdbTypes; t->mbdb_typename != NULL; ++t)
      {
            if (strlen(t->mbdb_typename) == namelen &&
                strncmp(name, t->mbdb_typename, namelen) == 0)
            {
                  err = EX_OK;
                  if (t->mbdb_initialize != NULL)
                        err = t->mbdb_initialize(arg);
                  if (err == EX_OK)
                        SmMbdbType = t;
                  return err;
            }
      }
      return EX_UNAVAILABLE;
}

/*
**  SM_MBDB_TERMINATE -- terminate connection to the mailbox database
**
**    Because this function closes any cached file descriptors that
**    are being held open for the connection to the mailbox database,
**    it should be called for security reasons prior to dropping privileges
**    and execing another process.
**
**    Parameters:
**          none.
**
**    Results:
**          none.
*/

void
sm_mbdb_terminate()
{
      if (SmMbdbType->mbdb_terminate != NULL)
            SmMbdbType->mbdb_terminate();
}

/*
**  SM_MBDB_LOOKUP -- look up a local mail recipient, given name
**
**    Parameters:
**          name -- name of local mail recipient
**          user -- pointer to structure to fill in on success
**
**    Results:
**          On success, fill in *user and return EX_OK.
**          If the user does not exist, return EX_NOUSER.
**          If a temporary failure (eg, a network failure) occurred,
**          return EX_TEMPFAIL.  Otherwise return EX_OSERR.
*/

int
sm_mbdb_lookup(name, user)
      char *name;
      SM_MBDB_T *user;
{
      int ret = EX_NOUSER;

      if (SmMbdbType->mbdb_lookup != NULL)
            ret = SmMbdbType->mbdb_lookup(name, user);
      return ret;
}

/*
**  SM_MBDB_FROMPW -- copy from struct pw to SM_MBDB_T
**
**    Parameters:
**          user -- destination user information structure
**          pw -- source passwd structure
**
**    Results:
**          none.
*/

void
sm_mbdb_frompw(user, pw)
      SM_MBDB_T *user;
      struct passwd *pw;
{
      SM_REQUIRE(user != NULL);
      (void) sm_strlcpy(user->mbdb_name, pw->pw_name,
                    sizeof(user->mbdb_name));
      user->mbdb_uid = pw->pw_uid;
      user->mbdb_gid = pw->pw_gid;
      sm_pwfullname(pw->pw_gecos, pw->pw_name, user->mbdb_fullname,
                  sizeof(user->mbdb_fullname));
      (void) sm_strlcpy(user->mbdb_homedir, pw->pw_dir,
                    sizeof(user->mbdb_homedir));
      (void) sm_strlcpy(user->mbdb_shell, pw->pw_shell,
                    sizeof(user->mbdb_shell));
}

/*
**  SM_PWFULLNAME -- build full name of user from pw_gecos field.
**
**    This routine interprets the strange entry that would appear
**    in the GECOS field of the password file.
**
**    Parameters:
**          gecos -- name to build.
**          user -- the login name of this user (for &).
**          buf -- place to put the result.
**          buflen -- length of buf.
**
**    Returns:
**          none.
*/

#if _FFR_HANDLE_ISO8859_GECOS
static char Latin1ToASCII[128] =
{
      32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32,
      32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 33,
      99, 80, 36, 89, 124, 36, 34, 99, 97, 60, 45, 45, 114, 45, 111, 42,
      50, 51, 39, 117, 80, 46, 44, 49, 111, 62, 42, 42, 42, 63, 65, 65,
      65, 65, 65, 65, 65, 67, 69, 69, 69, 69, 73, 73, 73, 73, 68, 78, 79,
      79, 79, 79, 79, 88, 79, 85, 85, 85, 85, 89, 80, 66, 97, 97, 97, 97,
      97, 97, 97, 99, 101, 101, 101, 101, 105, 105, 105, 105, 100, 110,
      111, 111, 111, 111, 111, 47, 111, 117, 117, 117, 117, 121, 112, 121
};
#endif /* _FFR_HANDLE_ISO8859_GECOS */

void
sm_pwfullname(gecos, user, buf, buflen)
      register char *gecos;
      char *user;
      char *buf;
      size_t buflen;
{
      register char *p;
      register char *bp = buf;

      if (*gecos == '*')
            gecos++;

      /* copy gecos, interpolating & to be full name */
      for (p = gecos; *p != '\0' && *p != ',' && *p != ';' && *p != '%'; p++)
      {
            if (bp >= &buf[buflen - 1])
            {
                  /* buffer overflow -- just use login name */
                  (void) sm_strlcpy(buf, user, buflen);
                  return;
            }
            if (*p == '&')
            {
                  /* interpolate full name */
                  (void) sm_strlcpy(bp, user, buflen - (bp - buf));
                  *bp = toupper(*bp);
                  bp += strlen(bp);
            }
            else
            {
#if _FFR_HANDLE_ISO8859_GECOS
                  if ((unsigned char) *p >= 128)
                        *bp++ = Latin1ToASCII[(unsigned char) *p - 128];
                  else
#endif /* _FFR_HANDLE_ISO8859_GECOS */
                        *bp++ = *p;
            }
      }
      *bp = '\0';
}

/*
**  /etc/passwd implementation.
*/

/*
**  MBDB_PW_INITIALIZE -- initialize getpwnam() version
**
**    Parameters:
**          arg -- unused.
**
**    Results:
**          EX_OK.
*/

/* ARGSUSED0 */
static int
mbdb_pw_initialize(arg)
      char *arg;
{
      return EX_OK;
}

/*
**  MBDB_PW_LOOKUP -- look up a local mail recipient, given name
**
**    Parameters:
**          name -- name of local mail recipient
**          user -- pointer to structure to fill in on success
**
**    Results:
**          On success, fill in *user and return EX_OK.
**          Failure: EX_NOUSER.
*/

static int
mbdb_pw_lookup(name, user)
      char *name;
      SM_MBDB_T *user;
{
      struct passwd *pw;

#ifdef HESIOD
      /* DEC Hesiod getpwnam accepts numeric strings -- short circuit it */
      {
            char *p;

            for (p = name; *p != '\0'; p++)
                  if (!isascii(*p) || !isdigit(*p))
                        break;
            if (*p == '\0')
                  return EX_NOUSER;
      }
#endif /* HESIOD */

      errno = 0;
      pw = getpwnam(name);
      if (pw == NULL)
      {
#ifdef WIN32
            errno = pwd_errno();
#endif /* WIN32 */
#if 0
            /*
            **  getpwnam() isn't advertised as setting errno.
            **  In fact, under FreeBSD, non-root getpwnam() on
            **  non-existant users returns NULL with errno = EPERM.
            **  This test won't work.
            */
            switch (errno)
            {
              case 0:
                  return EX_NOUSER;
              case EIO:
                  return EX_OSERR;
              default:
                  return EX_TEMPFAIL;
            }
#endif /* 0 */
            return EX_NOUSER;
      }

      sm_mbdb_frompw(user, pw);
      return EX_OK;
}

/*
**  MBDB_PW_TERMINATE -- terminate connection to the mailbox database
**
**    Parameters:
**          none.
**
**    Results:
**          none.
*/

static void
mbdb_pw_terminate()
{
      endpwent();
}

#if LDAPMAP
# if _LDAP_EXAMPLE_
/*
**  LDAP example implementation based on RFC 2307, "An Approach for Using
**  LDAP as a Network Information Service":
**
**    ( nisSchema.1.0 NAME 'uidNumber'
**      DESC 'An integer uniquely identifying a user in an
**          administrative domain'
**      EQUALITY integerMatch SYNTAX 'INTEGER' SINGLE-VALUE )
**
**    ( nisSchema.1.1 NAME 'gidNumber'
**      DESC 'An integer uniquely identifying a group in an
**          administrative domain'
**      EQUALITY integerMatch SYNTAX 'INTEGER' SINGLE-VALUE )
**
**    ( nisSchema.1.2 NAME 'gecos'
**      DESC 'The GECOS field; the common name'
**      EQUALITY caseIgnoreIA5Match
**      SUBSTRINGS caseIgnoreIA5SubstringsMatch
**      SYNTAX 'IA5String' SINGLE-VALUE )
**
**    ( nisSchema.1.3 NAME 'homeDirectory'
**      DESC 'The absolute path to the home directory'
**      EQUALITY caseExactIA5Match
**      SYNTAX 'IA5String' SINGLE-VALUE )
**
**    ( nisSchema.1.4 NAME 'loginShell'
**      DESC 'The path to the login shell'
**      EQUALITY caseExactIA5Match
**      SYNTAX 'IA5String' SINGLE-VALUE )
**
**    ( nisSchema.2.0 NAME 'posixAccount' SUP top AUXILIARY
**      DESC 'Abstraction of an account with POSIX attributes'
**      MUST ( cn $ uid $ uidNumber $ gidNumber $ homeDirectory )
**      MAY ( userPassword $ loginShell $ gecos $ description ) )
**
*/

#  define MBDB_LDAP_LABEL           "MailboxDatabase"

#  ifndef MBDB_LDAP_FILTER
#   define MBDB_LDAP_FILTER         "(&(objectClass=posixAccount)(uid=%0))"
#  endif /* MBDB_LDAP_FILTER */

#  ifndef MBDB_DEFAULT_LDAP_BASEDN
#   define MBDB_DEFAULT_LDAP_BASEDN NULL
#  endif /* MBDB_DEFAULT_LDAP_BASEDN */

#  ifndef MBDB_DEFAULT_LDAP_SERVER
#   define MBDB_DEFAULT_LDAP_SERVER NULL
#  endif /* MBDB_DEFAULT_LDAP_SERVER */

/*
**  MBDB_LDAP_INITIALIZE -- initialize LDAP version
**
**    Parameters:
**          arg -- LDAP specification
**
**    Results:
**          EX_OK on success, or an EX_* code on failure.
*/

static int
mbdb_ldap_initialize(arg)
      char *arg;
{
      sm_ldap_clear(&LDAPLMAP);
      LDAPLMAP.ldap_base = MBDB_DEFAULT_LDAP_BASEDN;
      LDAPLMAP.ldap_host = MBDB_DEFAULT_LDAP_SERVER;
      LDAPLMAP.ldap_filter = MBDB_LDAP_FILTER;

      /* Only want one match */
      LDAPLMAP.ldap_sizelimit = 1;

      /* interpolate new ldap_base and ldap_host from arg if given */
      if (arg != NULL && *arg != '\0')
      {
            char *new;
            char *sep;
            size_t len;

            len = strlen(arg) + 1;
            new = sm_malloc(len);
            if (new == NULL)
                  return EX_TEMPFAIL;
            (void) sm_strlcpy(new, arg, len);
            sep = strrchr(new, '@');
            if (sep != NULL)
            {
                  *sep++ = '\0';
                  LDAPLMAP.ldap_host = sep;
            }
            LDAPLMAP.ldap_base = new;
      }
      return EX_OK;
}


/*
**  MBDB_LDAP_LOOKUP -- look up a local mail recipient, given name
**
**    Parameters:
**          name -- name of local mail recipient
**          user -- pointer to structure to fill in on success
**
**    Results:
**          On success, fill in *user and return EX_OK.
**          Failure: EX_NOUSER.
*/

#define NEED_FULLNAME   0x01
#define NEED_HOMEDIR    0x02
#define NEED_SHELL      0x04
#define NEED_UID  0x08
#define NEED_GID  0x10

static int
mbdb_ldap_lookup(name, user)
      char *name;
      SM_MBDB_T *user;
{
      int msgid;
      int need;
      int ret;
      int save_errno;
      LDAPMessage *entry;
      BerElement *ber;
      char *attr = NULL;

      if (strlen(name) >= sizeof(user->mbdb_name))
      {
            errno = EINVAL;
            return EX_NOUSER;
      }

      if (LDAPLMAP.ldap_filter == NULL)
      {
            /* map not initialized, but don't have arg here */
            errno = EFAULT;
            return EX_TEMPFAIL;
      }

      if (LDAPLMAP.ldap_pid != getpid())
      {
            /* re-open map in this child process */
            LDAPLMAP.ldap_ld = NULL;
      }

      if (LDAPLMAP.ldap_ld == NULL)
      {
            /* map not open, try to open now */
            if (!sm_ldap_start(MBDB_LDAP_LABEL, &LDAPLMAP))
                  return EX_TEMPFAIL;
      }

      sm_ldap_setopts(LDAPLMAP.ldap_ld, &LDAPLMAP);
      msgid = sm_ldap_search(&LDAPLMAP, name);
      if (msgid == -1)
      {
            save_errno = sm_ldap_geterrno(LDAPLMAP.ldap_ld) + E_LDAPBASE;
#  ifdef LDAP_SERVER_DOWN
            if (errno == LDAP_SERVER_DOWN)
            {
                  /* server disappeared, try reopen on next search */
                  sm_ldap_close(&LDAPLMAP);
            }
#  endif /* LDAP_SERVER_DOWN */
            errno = save_errno;
            return EX_TEMPFAIL;
      }

      /* Get results */
      ret = ldap_result(LDAPLMAP.ldap_ld, msgid, 1,
                    (LDAPLMAP.ldap_timeout.tv_sec == 0 ? NULL :
                     &(LDAPLMAP.ldap_timeout)),
                    &(LDAPLMAP.ldap_res));

      if (ret != LDAP_RES_SEARCH_RESULT &&
          ret != LDAP_RES_SEARCH_ENTRY)
      {
            if (ret == 0)
                  errno = ETIMEDOUT;
            else
                  errno = sm_ldap_geterrno(LDAPLMAP.ldap_ld);
            ret = EX_TEMPFAIL;
            goto abort;
      }

      entry = ldap_first_entry(LDAPLMAP.ldap_ld, LDAPLMAP.ldap_res);
      if (entry == NULL)
      {
            save_errno = sm_ldap_geterrno(LDAPLMAP.ldap_ld);
            if (save_errno == LDAP_SUCCESS)
            {
                  errno = ENOENT;
                  ret = EX_NOUSER;
            }
            else
            {
                  errno = save_errno;
                  ret = EX_TEMPFAIL;
            }
            goto abort;
      }

# if !defined(LDAP_VERSION_MAX) && !defined(LDAP_OPT_SIZELIMIT)
      /*
      **  Reset value to prevent lingering
      **  LDAP_DECODING_ERROR due to
      **  OpenLDAP 1.X's hack (see below)
      */

      LDAPLMAP.ldap_ld->ld_errno = LDAP_SUCCESS;
# endif /* !defined(LDAP_VERSION_MAX) !defined(LDAP_OPT_SIZELIMIT) */

      ret = EX_OK;
      need = NEED_FULLNAME|NEED_HOMEDIR|NEED_SHELL|NEED_UID|NEED_GID;
      for (attr = ldap_first_attribute(LDAPLMAP.ldap_ld, entry, &ber);
           attr != NULL;
           attr = ldap_next_attribute(LDAPLMAP.ldap_ld, entry, ber))
      {
            char **vals;

            vals = ldap_get_values(LDAPLMAP.ldap_ld, entry, attr);
            if (vals == NULL)
            {
                  errno = sm_ldap_geterrno(LDAPLMAP.ldap_ld);
                  if (errno == LDAP_SUCCESS)
                  {
                        ldap_memfree(attr);
                        continue;
                  }

                  /* Must be an error */
                  errno += E_LDAPBASE;
                  ret = EX_TEMPFAIL;
                  goto abort;
            }

# if !defined(LDAP_VERSION_MAX) && !defined(LDAP_OPT_SIZELIMIT)
            /*
            **  Reset value to prevent lingering
            **  LDAP_DECODING_ERROR due to
            **  OpenLDAP 1.X's hack (see below)
            */

            LDAPLMAP.ldap_ld->ld_errno = LDAP_SUCCESS;
# endif /* !defined(LDAP_VERSION_MAX) !defined(LDAP_OPT_SIZELIMIT) */

            if (vals[0] == NULL || vals[0][0] == '\0')
                  goto skip;

            if (strcasecmp(attr, "gecos") == 0)
            {
                  if (!bitset(NEED_FULLNAME, need) ||
                      strlen(vals[0]) >= sizeof(user->mbdb_fullname))
                        goto skip;

                  sm_pwfullname(vals[0], name, user->mbdb_fullname,
                              sizeof(user->mbdb_fullname));
                  need &= ~NEED_FULLNAME;
            }
            else if (strcasecmp(attr, "homeDirectory") == 0)
            {
                  if (!bitset(NEED_HOMEDIR, need) ||
                      strlen(vals[0]) >= sizeof(user->mbdb_homedir))
                        goto skip;

                  (void) sm_strlcpy(user->mbdb_homedir, vals[0],
                                sizeof(user->mbdb_homedir));
                  need &= ~NEED_HOMEDIR;
            }
            else if (strcasecmp(attr, "loginShell") == 0)
            {
                  if (!bitset(NEED_SHELL, need) ||
                      strlen(vals[0]) >= sizeof(user->mbdb_shell))
                        goto skip;

                  (void) sm_strlcpy(user->mbdb_shell, vals[0],
                                sizeof(user->mbdb_shell));
                  need &= ~NEED_SHELL;
            }
            else if (strcasecmp(attr, "uidNumber") == 0)
            {
                  char *p;

                  if (!bitset(NEED_UID, need))
                        goto skip;

                  for (p = vals[0]; *p != '\0'; p++)
                  {
                        /* allow negative numbers */
                        if (p == vals[0] && *p == '-')
                        {
                              /* but not simply '-' */
                              if (*(p + 1) == '\0')
                                    goto skip;
                        }
                        else if (!isascii(*p) || !isdigit(*p))
                              goto skip;
                  }
                  user->mbdb_uid = atoi(vals[0]);
                  need &= ~NEED_UID;
            }
            else if (strcasecmp(attr, "gidNumber") == 0)
            {
                  char *p;

                  if (!bitset(NEED_GID, need))
                        goto skip;

                  for (p = vals[0]; *p != '\0'; p++)
                  {
                        /* allow negative numbers */
                        if (p == vals[0] && *p == '-')
                        {
                              /* but not simply '-' */
                              if (*(p + 1) == '\0')
                                    goto skip;
                        }
                        else if (!isascii(*p) || !isdigit(*p))
                              goto skip;
                  }
                  user->mbdb_gid = atoi(vals[0]);
                  need &= ~NEED_GID;
            }

skip:
            ldap_value_free(vals);
            ldap_memfree(attr);
      }

      errno = sm_ldap_geterrno(LDAPLMAP.ldap_ld);

      /*
      **  We check errno != LDAP_DECODING_ERROR since
      **  OpenLDAP 1.X has a very ugly *undocumented*
      **  hack of returning this error code from
      **  ldap_next_attribute() if the library freed the
      **  ber attribute.  See:
      **  http://www.openldap.org/lists/openldap-devel/9901/msg00064.html
      */

      if (errno != LDAP_SUCCESS &&
          errno != LDAP_DECODING_ERROR)
      {
            /* Must be an error */
            errno += E_LDAPBASE;
            ret = EX_TEMPFAIL;
            goto abort;
      }

 abort:
      save_errno = errno;
      if (attr != NULL)
      {
            ldap_memfree(attr);
            attr = NULL;
      }
      if (LDAPLMAP.ldap_res != NULL)
      {
            ldap_msgfree(LDAPLMAP.ldap_res);
            LDAPLMAP.ldap_res = NULL;
      }
      if (ret == EX_OK)
      {
            if (need == 0)
            {
                  (void) sm_strlcpy(user->mbdb_name, name,
                                sizeof(user->mbdb_name));
                  save_errno = 0;
            }
            else
            {
                  ret = EX_NOUSER;
                  save_errno = EINVAL;
            }
      }
      errno = save_errno;
      return ret;
}

/*
**  MBDB_LDAP_TERMINATE -- terminate connection to the mailbox database
**
**    Parameters:
**          none.
**
**    Results:
**          none.
*/

static void
mbdb_ldap_terminate()
{
      sm_ldap_close(&LDAPLMAP);
}
# endif /* _LDAP_EXAMPLE_ */
#endif /* LDAPMAP */

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