/*
 * 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);
}