sendmail/libsm/mbdb.c

/*
 * Copyright (c) 2001-2003,2009 Proofpoint, 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 1.43 2014-01-08 17:03:15 ca 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>
# ifdef EX_OK
#  undef EX_OK          /* for SVr4.2 SMP */
# endif /* EX_OK */
#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)
    {
#if _FFR_USE_GETPWNAM_ERRNO
        /*
        **  Only enable this code iff
        **  user unknown <-> getpwnam() == NULL && errno == 0
        **  (i.e., errno unchanged); see the POSIX spec.
        */

        if (errno != 0)
            return EX_TEMPFAIL;
#endif /* _FFR_USE_GETPWNAM_ERRNO */
        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)
    {
        int rc;

        /*
        **  We may have gotten an LDAP_RES_SEARCH_RESULT response
        **  with an error inside it, so we have to extract that
        **  with ldap_parse_result().  This can happen when talking
        **  to an LDAP proxy whose backend has gone down.
        */

        save_errno = ldap_parse_result(LDAPLMAP.ldap_ld,
                           LDAPLMAP.ldap_res, &rc, NULL,
                           NULL, NULL, NULL, 0);
        if (save_errno == LDAP_SUCCESS)
            save_errno = rc;
        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 */