lib/passwdutil/switch_utils.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#include <sys/types.h>
#include <nsswitch.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <syslog.h>
#include <stdlib.h>
#include <unistd.h>

#include "ns_sldap.h"
#include <nss_dbdefs.h>
#include <nsswitch.h>
#include <pwd.h>
#include <shadow.h>
#include <rpcsvc/nis.h>

#include "passwdutil.h"

/*
 * name_to_int(rep)
 *
 * Translate the repository to a bitmask.
 * if we don't recognise the repository name, we return REP_ERANGE
 */
int
name_to_int(char *rep_name)
{
    int result = REP_ERANGE;

    if (strcmp(rep_name, "files") == 0)
        result = REP_FILES;
    else if (strcmp(rep_name, "nis") == 0)
        result = REP_NIS;
    else if (strcmp(rep_name, "ldap") == 0)
        result = REP_LDAP;
    else if (strcmp(rep_name, "compat") == 0) {
        struct __nsw_switchconfig *cfg;
        enum   __nsw_parse_err pserr;

        cfg = __nsw_getconfig("passwd_compat", &pserr);
        if (cfg == NULL) {
            result = REP_FILES | REP_NIS;
        } else {
            if (strcmp(cfg->lookups->service_name, "ldap") == 0)
                result = REP_FILES | REP_LDAP;
            else
                result = REP_ERANGE;
            (void) __nsw_freeconfig(cfg);
        }
    }

    return (result);
}

/*
 * Figure out which repository we use in compat mode.
 */
int
get_compat_mode(void)
{
    struct __nsw_switchconfig *cfg;
    enum   __nsw_parse_err pserr;
    int result = REP_COMPAT_NIS;

    if ((cfg = __nsw_getconfig("passwd_compat", &pserr)) != NULL) {
        if (strcmp(cfg->lookups->service_name, "ldap") == 0)
            result = REP_COMPAT_LDAP;
    }
    (void) __nsw_freeconfig(cfg);

    return (result);
}

/*
 * get_ns(rep, accesstype)
 *
 * returns a bitmask of repositories to use based on either
 *   1. the repository that is given as argument
 *   2. the nsswitch.conf file
 *   3. the type of access requested
 *
 * "accesstype" indicates whether we are reading from or writing to the
 * repository. We need to know this since "compat" will translate into
 * REP_NSS (the nss-switch) for READ access (needed to decode
 * the black-magic '+' entries) but it translates into a bitmask
 * on WRITE access.
 *
 * If we detect read-access in compat mode, we augment the result
 * with one of REP_COMPAT_{NIS,LDAP}. We need this in order to
 * implement ATTR_REP_NAME in nss_getpwnam.
 *
 * A return value of REP_NOREP indicates an error.
 */
int
get_ns(pwu_repository_t *rep, int accesstype)
{
    struct __nsw_switchconfig *conf = NULL;
    enum __nsw_parse_err pserr;
    struct __nsw_lookup *lkp;
    struct __nsw_lookup *lkp2;
    struct __nsw_lookup *lkp3;
    struct __nsw_lookup *lkpn;
    int result = REP_NOREP;

    if (rep != PWU_DEFAULT_REP) {
        result = name_to_int(rep->type);
        return (result);
    }

    conf = __nsw_getconfig("passwd", &pserr);
    if (conf == NULL) {
        /*
         * No config found. The user didn't supply a repository,
         * so we try to change the password in the default
         * repositories (files and nis) even though we cannot
         * find the name service switch entry. (Backward compat)
         */
        syslog(LOG_ERR, "passwdutil.so: nameservice switch entry for "
            "passwd not found.");
        result = REP_FILES | REP_NIS;
        return (result);
    }

    lkp = conf->lookups;

    /*
     * Supported nsswitch.conf can have a maximum of 3 repositories.
     * If we encounter an unsupported nsswitch.conf, we return REP_NSS
     * to fall back to the nsswitch backend.
     *
     * Note that specifying 'ad' in the configuration is acceptable
     * though changing AD users' passwords through passwd(1) is not.
     * Therefore "ad" will be silently ignored.
     */
    if (conf->num_lookups == 1) {
        /* files or compat */

        if (strcmp(lkp->service_name, "files") == 0) {
            result = name_to_int(lkp->service_name);
        } else if (strcmp(lkp->service_name, "compat") == 0) {
            if (accesstype == PWU_READ)
                result = REP_NSS | get_compat_mode();
            else
                result = name_to_int(lkp->service_name);
        } else
            result = REP_NSS;

    } else if (conf->num_lookups == 2) {
        lkp2 = lkp->next;
        if (strcmp(lkp->service_name, "files") == 0) {
            result = REP_FILES;
            if (strcmp(lkp2->service_name, "ldap") == 0)
                result |= REP_LDAP;
            else if (strcmp(lkp2->service_name, "nis") == 0)
                result |= REP_NIS;
            else if (strcmp(lkp2->service_name, "ad") != 0)
                result = REP_NSS;
            /* AD is ignored */
        } else {
            result = REP_NSS;
        }
    } else if (conf->num_lookups == 3) {
        /*
         * Valid configurations with 3 repositories are:
         *   files ad [nis | ldap ] OR
         *   files [nis | ldap ] ad
         */
        lkp2 = lkp->next;
        lkp3 = lkp2->next;
        if (strcmp(lkp2->service_name, "ad") == 0)
            lkpn = lkp3;
        else if (strcmp(lkp3->service_name, "ad") == 0)
            lkpn = lkp2;
        else
            lkpn = NULL;
        if (strcmp(lkp->service_name, "files") == 0 &&
            lkpn != NULL) {
            result = REP_FILES;
            if (strcmp(lkpn->service_name, "ldap") == 0)
                result |= REP_LDAP;
            else if (strcmp(lkpn->service_name, "nis") == 0)
                result |= REP_NIS;
            else
                result = REP_NSS;
        } else {
            result = REP_NSS;
        }
    } else {
        result = REP_NSS;
    }

    (void) __nsw_freeconfig(conf);
    return (result);
}

static void
nss_ldap_passwd(p)
    nss_db_params_t *p;
{
    p->name = NSS_DBNAM_PASSWD;
    p->flags |= NSS_USE_DEFAULT_CONFIG;
    p->default_config = "ldap";
}

static void
nss_ldap_shadow(p)
    nss_db_params_t *p;
{
    p->name = NSS_DBNAM_SHADOW;
    p->config_name    = NSS_DBNAM_PASSWD;   /* Use config for "passwd" */
    p->flags |= NSS_USE_DEFAULT_CONFIG;
    p->default_config = "ldap";
}


#ifdef PAM_NIS
static void
nss_nis_passwd(p)
    nss_db_params_t *p;
{
    p->name = NSS_DBNAM_PASSWD;
    p->flags |= NSS_USE_DEFAULT_CONFIG;
    p->default_config = "nis";
}

static void
nss_nis_shadow(p)
    nss_db_params_t *p;
{
    p->name = NSS_DBNAM_SHADOW;
    p->config_name    = NSS_DBNAM_PASSWD;   /* Use config for "passwd" */
    p->flags |= NSS_USE_DEFAULT_CONFIG;
    p->default_config = "nis";
}
#endif /* PAM_NIS */

static char *
gettok(nextpp)
    char    **nextpp;
{
    char    *p = *nextpp;
    char    *q = p;
    char    c;

    if (p == 0) {
        return (0);
    }
    while ((c = *q) != '\0' && c != ':') {
        q++;
    }
    if (c == '\0') {
        *nextpp = 0;
    } else {
        *q++ = '\0';
        *nextpp = q;
    }
    return (p);
}

/*
 * Return values: 0 = success, 1 = parse error, 2 = erange ...
 * The structure pointer passed in is a structure in the caller's space
 * wherein the field pointers would be set to areas in the buffer if
 * need be. instring and buffer should be separate areas.
 */
static int
str2passwd(const char *instr, int lenstr, void *ent, char *buffer, int buflen)
{
    struct passwd   *passwd = (struct passwd *)ent;
    char        *p, *next;
    int     black_magic;    /* "+" or "-" entry */

    if (lenstr + 1 > buflen) {
        return (NSS_STR_PARSE_ERANGE);
    }
    /*
     * We copy the input string into the output buffer and
     * operate on it in place.
     */
    (void) memcpy(buffer, instr, lenstr);
    buffer[lenstr] = '\0';

    next = buffer;

    passwd->pw_name = p = gettok(&next);        /* username */
    if (*p == '\0') {
        /* Empty username;  not allowed */
        return (NSS_STR_PARSE_PARSE);
    }
    black_magic = (*p == '+' || *p == '-');
    if (black_magic) {
        passwd->pw_uid  = UID_NOBODY;
        passwd->pw_gid  = GID_NOBODY;
        /*
         * pwconv tests pw_passwd and pw_age == NULL
         */
        passwd->pw_passwd = "";
        passwd->pw_age  = "";
        /*
         * the rest of the passwd entry is "optional"
         */
        passwd->pw_comment = "";
        passwd->pw_gecos = "";
        passwd->pw_dir  = "";
        passwd->pw_shell = "";
    }

    passwd->pw_passwd = p = gettok(&next);      /* password */
    if (p == 0) {
        if (black_magic)
            return (NSS_STR_PARSE_SUCCESS);
        else
            return (NSS_STR_PARSE_PARSE);
    }
    for (; *p != '\0'; p++) {           /* age */
        if (*p == ',') {
            *p++ = '\0';
            break;
        }
    }
    passwd->pw_age = p;

    p = next;                   /* uid */
    if (p == 0 || *p == '\0') {
        if (black_magic)
            return (NSS_STR_PARSE_SUCCESS);
        else
            return (NSS_STR_PARSE_PARSE);
    }
    if (!black_magic) {
        passwd->pw_uid = strtol(p, &next, 10);
        if (next == p) {
            /* uid field should be nonempty */
            return (NSS_STR_PARSE_PARSE);
        }
        /*
         * The old code (in 2.0 thru 2.5) would check
         * for the uid being negative, or being greater
         * than 60001 (the rfs limit).  If it met either of
         * these conditions, the uid was translated to 60001.
         *
         * Now we just check for ephemeral uids; anything else
         * is administrative policy
         */
        if (passwd->pw_uid > MAXUID)
            passwd->pw_uid = UID_NOBODY;
    }
    if (*next++ != ':') {
        if (black_magic)
            p = gettok(&next);
        else
            return (NSS_STR_PARSE_PARSE);
    }
    p = next;                   /* gid */
    if (p == 0 || *p == '\0') {
        if (black_magic)
            return (NSS_STR_PARSE_SUCCESS);
        else
            return (NSS_STR_PARSE_PARSE);
    }
    if (!black_magic) {
        passwd->pw_gid = strtol(p, &next, 10);
        if (next == p) {
            /* gid field should be nonempty */
            return (NSS_STR_PARSE_PARSE);
        }
        /*
         * gid should be non-negative; anything else
         * is administrative policy.
         */
        if (passwd->pw_gid > MAXUID)
            passwd->pw_gid = GID_NOBODY;
    }
    if (*next++ != ':') {
        if (black_magic)
            p = gettok(&next);
        else
            return (NSS_STR_PARSE_PARSE);
    }

    passwd->pw_gecos = passwd->pw_comment = p = gettok(&next);
    if (p == 0) {
        if (black_magic)
            return (NSS_STR_PARSE_SUCCESS);
        else
            return (NSS_STR_PARSE_PARSE);
    }

    passwd->pw_dir = p = gettok(&next);
    if (p == 0) {
        if (black_magic)
            return (NSS_STR_PARSE_SUCCESS);
        else
            return (NSS_STR_PARSE_PARSE);
    }

    passwd->pw_shell = p = gettok(&next);
    if (p == 0) {
        if (black_magic)
            return (NSS_STR_PARSE_SUCCESS);
        else
            return (NSS_STR_PARSE_PARSE);
    }

    /* Better not be any more fields... */
    if (next == 0) {
        /* Successfully parsed and stored */
        return (NSS_STR_PARSE_SUCCESS);
    }
    return (NSS_STR_PARSE_PARSE);
}

typedef const char *constp;

/*
 * Return value 1 means success and more input, 0 means error or no more
 */
static int
getfield(nextp, limit, uns, valp)
    constp      *nextp;
    constp      limit;
    int     uns;
    void        *valp;
{
    constp      p = *nextp;
    char        *endfield;
    char        numbuf[12];  /* Holds -2^31 and trailing ':' */
    int     len;
    long        x;
    unsigned long   ux;

    if (p == 0 || p >= limit) {
        return (0);
    }
    if (*p == ':') {
        p++;
        *nextp = p;
        return (p < limit);
    }
    if ((len = limit - p) > sizeof (numbuf) - 1) {
        len = sizeof (numbuf) - 1;
    }
    /*
     * We want to use strtol() and we have a readonly non-zero-terminated
     *   string, so first we copy and terminate the interesting bit.
     *   Ugh.  (It's convenient to terminate with a colon rather than \0).
     */
    if ((endfield = memccpy(numbuf, p, ':', len)) == 0) {
        if (len != limit - p) {
            /* Error -- field is too big to be a legit number */
            return (0);
        }
        numbuf[len] = ':';
        p = limit;
    } else {
        p += (endfield - numbuf);
    }
    if (uns) {
        ux = strtoul(numbuf, &endfield, 10);
        if (*endfield != ':') {
            /* Error -- expected <integer><colon> */
            return (0);
        }
        *((unsigned int *)valp) = (unsigned int)ux;
    } else {
        x = strtol(numbuf, &endfield, 10);
        if (*endfield != ':') {
            /* Error -- expected <integer><colon> */
            return (0);
        }
        *((int *)valp) = (int)x;
    }
    *nextp = p;
    return (p < limit);
}

/*
 *  str2spwd() -- convert a string to a shadow passwd entry.  The parser is
 *  more liberal than the passwd or group parsers;  since it's legitimate
 *  for almost all the fields here to be blank, the parser lets one omit
 *  any number of blank fields at the end of the entry.  The acceptable
 *  forms for '+' and '-' entries are the same as those for normal entries.
 *  === Is this likely to do more harm than good?
 *
 * Return values: 0 = success, 1 = parse error, 2 = erange ...
 * The structure pointer passed in is a structure in the caller's space
 * wherein the field pointers would be set to areas in the buffer if
 * need be. instring and buffer should be separate areas.
 */
int
str2spwd(instr, lenstr, ent, buffer, buflen)
    const char  *instr;
    int     lenstr;
    void    *ent; /* really (struct spwd *) */
    char    *buffer;
    int buflen;
{
    struct spwd *shadow = (struct spwd *)ent;
    const char  *p = instr, *limit;
    char        *bufp;
    int lencopy, black_magic;

    limit = p + lenstr;
    if ((p = memchr(instr, ':', lenstr)) == 0 ||
        ++p >= limit ||
        (p = memchr(p, ':', limit - p)) == 0) {
        lencopy = lenstr;
        p = 0;
    } else {
        lencopy = p - instr;
        p++;
    }
    if (lencopy + 1 > buflen) {
        return (NSS_STR_PARSE_ERANGE);
    }
    (void) memcpy(buffer, instr, lencopy);
    buffer[lencopy] = 0;

    black_magic = (*instr == '+' || *instr == '-');
    shadow->sp_namp = bufp = buffer;
    shadow->sp_pwdp = 0;
    shadow->sp_lstchg = -1;
    shadow->sp_min  = -1;
    shadow->sp_max  = -1;
    shadow->sp_warn = -1;
    shadow->sp_inact = -1;
    shadow->sp_expire = -1;
    shadow->sp_flag = 0;

    if ((bufp = strchr(bufp, ':')) == 0) {
        if (black_magic)
            return (NSS_STR_PARSE_SUCCESS);
        else
            return (NSS_STR_PARSE_PARSE);
    }
    *bufp++ = '\0';

    shadow->sp_pwdp = bufp;
    if (instr == 0) {
        if ((bufp = strchr(bufp, ':')) == 0) {
            if (black_magic)
                return (NSS_STR_PARSE_SUCCESS);
            else
                return (NSS_STR_PARSE_PARSE);
        }
        *bufp++ = '\0';
        p = bufp;
    } /* else p was set when we copied name and passwd into the buffer */

    if (!getfield(&p, limit, 0, &shadow->sp_lstchg))
            return (NSS_STR_PARSE_SUCCESS);
    if (!getfield(&p, limit, 0, &shadow->sp_min))
            return (NSS_STR_PARSE_SUCCESS);
    if (!getfield(&p, limit, 0, &shadow->sp_max))
            return (NSS_STR_PARSE_SUCCESS);
    if (!getfield(&p, limit, 0, &shadow->sp_warn))
            return (NSS_STR_PARSE_SUCCESS);
    if (!getfield(&p, limit, 0, &shadow->sp_inact))
            return (NSS_STR_PARSE_SUCCESS);
    if (!getfield(&p, limit, 0, &shadow->sp_expire))
            return (NSS_STR_PARSE_SUCCESS);
    if (!getfield(&p, limit, 1, &shadow->sp_flag))
            return (NSS_STR_PARSE_SUCCESS);
    if (p != limit) {
        /* Syntax error -- garbage at end of line */
        return (NSS_STR_PARSE_PARSE);
    }
    return (NSS_STR_PARSE_SUCCESS);
}

static nss_XbyY_buf_t *buffer;
static DEFINE_NSS_DB_ROOT(db_root);

#define GETBUF()    \
    NSS_XbyY_ALLOC(&buffer, sizeof (struct passwd), NSS_BUFLEN_PASSWD)

#pragma fini(endutilpwent)

static void
endutilpwent(void)
{
    NSS_XbyY_FREE(&buffer);
    nss_delete(&db_root);
}

/*ARGSUSED*/
struct passwd *
getpwnam_from(const char *name, pwu_repository_t *rep, int reptype)
{
    nss_XbyY_buf_t  *b = GETBUF();
    nss_XbyY_args_t arg;

    if (b == 0)
        return (0);

    NSS_XbyY_INIT(&arg, b->result, b->buffer, b->buflen, str2passwd);
    arg.key.name = name;

    switch (reptype) {
    case REP_LDAP:
        (void) nss_search(&db_root, nss_ldap_passwd,
            NSS_DBOP_PASSWD_BYNAME, &arg);
        break;
#ifdef PAM_NIS
    case REP_NIS:
        (void) nss_search(&db_root, nss_nis_passwd,
            NSS_DBOP_PASSWD_BYNAME, &arg);
        break;
#endif
    default:
        return (NULL);
    }

    return (struct passwd *)NSS_XbyY_FINI(&arg);
}

/*ARGSUSED*/
struct passwd *
getpwuid_from(uid_t uid, pwu_repository_t *rep, int reptype)
{
    nss_XbyY_buf_t  *b = GETBUF();
    nss_XbyY_args_t arg;

    if (b == 0)
        return (0);

    NSS_XbyY_INIT(&arg, b->result, b->buffer, b->buflen, str2passwd);
    arg.key.uid = uid;

    switch (reptype) {
    case REP_LDAP:
        (void) nss_search(&db_root, nss_ldap_passwd,
            NSS_DBOP_PASSWD_BYUID, &arg);
        break;
#ifdef PAM_NIS
    case REP_NIS:
        (void) nss_search(&db_root, nss_nis_passwd,
            NSS_DBOP_PASSWD_BYUID, &arg);
        break;
#endif
    default:
        return (NULL);
    }

    return (struct passwd *)NSS_XbyY_FINI(&arg);
}

static nss_XbyY_buf_t *spbuf;
static DEFINE_NSS_DB_ROOT(spdb_root);

#define GETSPBUF()  \
    NSS_XbyY_ALLOC(&spbuf, sizeof (struct spwd), NSS_BUFLEN_SHADOW)

#pragma fini(endutilspent)

static void
endutilspent(void)
{
    NSS_XbyY_FREE(&spbuf);
    nss_delete(&spdb_root);
}

/*ARGSUSED*/
struct spwd *
getspnam_from(const char *name, pwu_repository_t *rep, int reptype)
{
    nss_XbyY_buf_t  *b = GETSPBUF();
    nss_XbyY_args_t arg;

    if (b == 0)
        return (0);

    NSS_XbyY_INIT(&arg, b->result, b->buffer, b->buflen, str2spwd);
    arg.key.name = name;
    switch (reptype) {
    case REP_LDAP:
        (void) nss_search(&spdb_root, nss_ldap_shadow,
            NSS_DBOP_SHADOW_BYNAME, &arg);
        break;
#ifdef PAM_NIS
    case REP_NIS:
        (void) nss_search(&spdb_root, nss_nis_shadow,
            NSS_DBOP_SHADOW_BYNAME, &arg);
        break;
#endif
    default:
        return (NULL);
    }
    return (struct spwd *)NSS_XbyY_FINI(&arg);
}