/*

 * SPDX-License-Identifier: ISC

 *

 * Copyright (c) 1996, 1998-2005, 2007-2023, 2025

 *  Todd C. Miller <Todd.Miller@sudo.ws>

 *

 * Permission to use, copy, modify, and distribute this software for any

 * purpose with or without fee is hereby granted, provided that the above

 * copyright notice and this permission notice appear in all copies.

 *

 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR

 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

 *

 * Sponsored in part by the Defense Advanced Research Projects

 * Agency (DARPA) and Air Force Research Laboratory, Air Force

 * Materiel Command, USAF, under agreement number F39502-99-1-0512.

 */

/*

 * This is an open source non-commercial project. Dear PVS-Studio, please check it.

 * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com

 */

#include <config.h>

#include <sys/stat.h>

#ifdef HAVE_SYS_SYSTEMINFO_H

# include <sys/systeminfo.h>

#endif

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#ifdef HAVE_STRINGS_H

# include <strings.h>

#endif /* HAVE_STRINGS_H */

#include <unistd.h>

#ifdef HAVE_NETGROUP_H

# include <netgroup.h>

#else

# include <netdb.h>

#endif /* HAVE_NETGROUP_H */

#include <dirent.h>

#include <fcntl.h>

#include <pwd.h>

#include <grp.h>

#include <errno.h>

#ifdef HAVE_FNMATCH

# include <fnmatch.h>

#else

# include <compat/fnmatch.h>

#endif /* HAVE_FNMATCH */

#include <sudoers.h>

#include <gram.h>

/*

 * Check whether user described by pw matches member.

 * Returns ALLOW, DENY or UNSPEC.

 */

int

user_matches(const struct sudoers_parse_tree *parse_tree,

    const struct passwd *pw, const struct member *m)

{

    const struct sudoers_context *ctx = parse_tree->ctx;

    const char *lhost = parse_tree->lhost ? parse_tree->lhost : ctx->runas.host;

    const char *shost = parse_tree->shost ? parse_tree->shost : ctx->runas.shost;

    int matched = UNSPEC;

    struct alias *a;

    debug_decl(user_matches, SUDOERS_DEBUG_MATCH);

    switch (m->type) {

  case ALL:

      matched = m->negated ? DENY : ALLOW;

      break;

  case NETGROUP:

      if (netgr_matches(parse_tree->nss, m->name,

    def_netgroup_tuple ? lhost : NULL,

    def_netgroup_tuple ? shost : NULL, pw->pw_name) == ALLOW)

    matched = m->negated ? DENY : ALLOW;

      break;

  case USERGROUP:

      if (usergr_matches(m->name, pw->pw_name, pw) == ALLOW)

    matched = m->negated ? DENY : ALLOW;

      break;

  case ALIAS:

      if ((a = alias_get(parse_tree, m->name, USERALIAS)) != NULL) {

    /* XXX */

    const int rc = userlist_matches(parse_tree, pw, &a->members);

    if (SPECIFIED(rc)) {

        if (m->negated) {

      matched = rc == ALLOW ? DENY : ALLOW;

        } else {

      matched = rc;

        }

    }

    alias_put(a);

    break;

      }

      FALLTHROUGH;

  case WORD:

      if (userpw_matches(m->name, pw->pw_name, pw) == ALLOW)

    matched = m->negated ? DENY : ALLOW;

      break;

    }

    debug_return_int(matched);

}

/*

 * Check for user described by pw in a list of members.

 * Returns ALLOW, DENY or UNSPEC.

 */

int

userlist_matches(const struct sudoers_parse_tree *parse_tree,

    const struct passwd *pw, const struct member_list *list)

{

    struct member *m;

    int matched = UNSPEC;

    debug_decl(userlist_matches, SUDOERS_DEBUG_MATCH);

    TAILQ_FOREACH_REVERSE(m, list, member_list, entries) {

  matched = user_matches(parse_tree, pw, m);

  if (SPECIFIED(matched))

      break;

    }

    debug_return_int(matched);

}

struct gid_list *

runas_getgroups(const struct sudoers_context *ctx)

{

    const struct passwd *pw;

    debug_decl(runas_getgroups, SUDOERS_DEBUG_MATCH);

    if (def_preserve_groups) {

  sudo_gidlist_addref(ctx->user.gid_list);

  debug_return_ptr(ctx->user.gid_list);

    }

    /* Only use results from a group db query, not the front end. */

    pw = ctx->runas.pw ? ctx->runas.pw : ctx->user.pw;

    debug_return_ptr(sudo_get_gidlist(pw, ENTRY_TYPE_QUERIED));

}

/*

 * Check whether the requested runas user matches user_list, the

 * user portion of a sudoers runaslist.  If user_list is NULL, a

 * list containing runas_default is used.

 * Returns ALLOW, DENY or UNSPEC.

 */

static int

runas_userlist_matches(const struct sudoers_parse_tree *parse_tree,

    const struct member_list *user_list)

{

    const struct sudoers_context *ctx = parse_tree->ctx;

    const char *lhost = parse_tree->lhost ? parse_tree->lhost : ctx->runas.host;

    const char *shost = parse_tree->shost ? parse_tree->shost : ctx->runas.shost;

    int user_matched = UNSPEC;

    struct member *m;

    struct alias *a;

    debug_decl(runas_userlist_matches, SUDOERS_DEBUG_MATCH);

    TAILQ_FOREACH_REVERSE(m, user_list, member_list, entries) {

  switch (m->type) {

      case ALL:

    user_matched = m->negated ? DENY : ALLOW;

    break;

      case NETGROUP:

    if (netgr_matches(parse_tree->nss, m->name,

        def_netgroup_tuple ? lhost : NULL,

        def_netgroup_tuple ? shost : NULL,

        ctx->runas.pw->pw_name) == ALLOW)

        user_matched = m->negated ? DENY : ALLOW;

    break;

      case USERGROUP:

    if (usergr_matches(m->name, ctx->runas.pw->pw_name, ctx->runas.pw) == ALLOW)

        user_matched = m->negated ? DENY : ALLOW;

    break;

      case ALIAS:

    a = alias_get(parse_tree, m->name, RUNASALIAS);

    if (a != NULL) {

        const int rc = runas_userlist_matches(parse_tree,

      &a->members);

        if (SPECIFIED(rc)) {

      if (m->negated) {

          user_matched = rc == ALLOW ? DENY : ALLOW;

      } else {

          user_matched = rc;

      }

        }

        alias_put(a);

        break;

    }

    FALLTHROUGH;

      case WORD:

    if (userpw_matches(m->name, ctx->runas.pw->pw_name, ctx->runas.pw) == ALLOW)

        user_matched = m->negated ? DENY : ALLOW;

    break;

      case MYSELF:

    /*

     * Only match a rule with an empty runas user if a group

     * was specified on the command line without a user _or_

     * the user specified their own name on the command line.

     */

    if ((!ISSET(ctx->settings.flags, RUNAS_USER_SPECIFIED) &&

      ISSET(ctx->settings.flags, RUNAS_GROUP_SPECIFIED)) ||

      strcmp(ctx->user.name, ctx->runas.pw->pw_name) == 0)

        user_matched = m->negated ? DENY : ALLOW;

    break;

  }

    }

    debug_return_int(user_matched);

}

/*

 * Check whether the requested runas group matches group_list, the

 * group portion of a sudoers runaslist, or the runas user's groups.

 * Returns ALLOW, DENY or UNSPEC.

 */

static int

runas_grouplist_matches(const struct sudoers_parse_tree *parse_tree,

    const struct member_list *group_list, int user_matched)

{

    const struct sudoers_context *ctx = parse_tree->ctx;

    int group_matched = UNSPEC;

    struct member *m;

    struct alias *a;

    debug_decl(runas_grouplist_matches, SUDOERS_DEBUG_MATCH);

    if (group_list != NULL) {

  TAILQ_FOREACH_REVERSE(m, group_list, member_list, entries) {

      switch (m->type) {

    case ALL:

        group_matched = m->negated ? DENY : ALLOW;

        break;

    case ALIAS:

        a = alias_get(parse_tree, m->name, RUNASALIAS);

        if (a != NULL) {

      const int rc = runas_grouplist_matches(parse_tree,

          &a->members, user_matched);

      if (SPECIFIED(rc)) {

          if (m->negated) {

        group_matched = rc == ALLOW ? DENY : ALLOW;

          } else {

        group_matched = rc;

          }

      }

      alias_put(a);

      break;

        }

        FALLTHROUGH;

    case WORD:

        if (group_matches(m->name, ctx->runas.gr) == ALLOW)

      group_matched = m->negated ? DENY : ALLOW;

        break;

      }

  }

    }

    if (!SPECIFIED(group_matched) && user_matched == ALLOW) {

  struct gid_list *runas_groups;

  /*

   * The runas group was not explicitly allowed by sudoers.

   * If the runas user matched, check its group list too.

   */

  if (ctx->runas.pw->pw_gid == ctx->runas.gr->gr_gid) {

      group_matched = ALLOW; /* runas group matches passwd db */

  } else if ((runas_groups = runas_getgroups(ctx)) != NULL) {

      int i;

      for (i = 0; i < runas_groups->ngids; i++) {

    if (runas_groups->gids[i] == ctx->runas.gr->gr_gid) {

        group_matched = ALLOW; /* matched aux group vector */

        break;

    }

      }

      sudo_gidlist_delref(runas_groups);

  }

    }

    debug_return_int(group_matched);

}

/*

 * Check whether the sudoers runaslist, composed of user_list and

 * group_list, matches the runas user/group requested by the user.

 * Either (or both) user_list and group_list may be NULL.

 * If user_list is NULL, a list containing runas_default is used.

 * Returns ALLOW, DENY or UNSPEC.

 */

int

runaslist_matches(const struct sudoers_parse_tree *parse_tree,

    const struct member_list *user_list, const struct member_list *group_list)

{

    const struct sudoers_context *ctx = parse_tree->ctx;

    struct member_list _user_list = TAILQ_HEAD_INITIALIZER(_user_list);

    int user_matched, group_matched = UNSPEC;

    struct member m_user;

    debug_decl(runaslist_matches, SUDOERS_DEBUG_MATCH);

    /* If no runas user listed in sudoers, use the default value.  */

    if (user_list == NULL) {

  m_user.name = def_runas_default;

  m_user.type = WORD;

  m_user.negated = false;

  TAILQ_INSERT_HEAD(&_user_list, &m_user, entries);

  user_list = &_user_list;

    }

    user_matched = runas_userlist_matches(parse_tree, user_list);

    if (ISSET(ctx->settings.flags, RUNAS_GROUP_SPECIFIED)) {

  group_matched = runas_grouplist_matches(parse_tree, group_list,

      user_matched);

  /*

   * Allow "sudo -g group" or "sudo -u myname -g group"

   * if the runas group matches.

   */

  if (group_matched == ALLOW && user_matched == UNSPEC) {

      if (strcmp(ctx->user.name, ctx->runas.pw->pw_name) == 0)

    user_matched = ALLOW;

  }

    }

    if (user_matched == DENY || group_matched == DENY)

  debug_return_int(DENY);

    if (user_matched == group_matched || ctx->runas.gr == NULL)

  debug_return_int(user_matched);

    debug_return_int(UNSPEC);

}

/*

 * Check for lhost and shost in a list of members.

 * Returns ALLOW, DENY or UNSPEC.

 */

static int

hostlist_matches_int(const struct sudoers_parse_tree *parse_tree,

    const struct passwd *pw, const char *lhost, const char *shost,

    const struct member_list *list)

{

    struct member *m;

    int matched = UNSPEC;

    debug_decl(hostlist_matches, SUDOERS_DEBUG_MATCH);

    TAILQ_FOREACH_REVERSE(m, list, member_list, entries) {

  matched = host_matches(parse_tree, pw, lhost, shost, m);

  if (SPECIFIED(matched))

      break;

    }

    debug_return_int(matched);

}

/*

 * Check for ctx->runas.host and ctx->runas.shost in a list of members.

 * Returns ALLOW, DENY or UNSPEC.

 */

int

hostlist_matches(const struct sudoers_parse_tree *parse_tree,

    const struct passwd *pw, const struct member_list *list)

{

    const struct sudoers_context *ctx = parse_tree->ctx;

    const char *lhost = parse_tree->lhost ? parse_tree->lhost : ctx->runas.host;

    const char *shost = parse_tree->shost ? parse_tree->shost : ctx->runas.shost;

    return hostlist_matches_int(parse_tree, pw, lhost, shost, list);

}

/*

 * Check whether host or shost matches member.

 * Returns ALLOW, DENY or UNSPEC.

 */

int

host_matches(const struct sudoers_parse_tree *parse_tree,

    const struct passwd *pw, const char *lhost, const char *shost,

    const struct member *m)

{

    struct alias *a;

    int ret = UNSPEC;

    debug_decl(host_matches, SUDOERS_DEBUG_MATCH);

    switch (m->type) {

  case ALL:

      ret = m->negated ? DENY : ALLOW;

      break;

  case NETGROUP:

      if (netgr_matches(parse_tree->nss, m->name, lhost, shost,

    def_netgroup_tuple ? pw->pw_name : NULL) == ALLOW)

    ret = m->negated ? DENY : ALLOW;

      break;

  case NTWKADDR:

      if (addr_matches(m->name) == ALLOW)

    ret = m->negated ? DENY : ALLOW;

      break;

  case ALIAS:

      a = alias_get(parse_tree, m->name, HOSTALIAS);

      if (a != NULL) {

    /* XXX */

    const int rc = hostlist_matches_int(parse_tree, pw, lhost,

        shost, &a->members);

    if (SPECIFIED(rc)) {

        if (m->negated) {

      ret = rc == ALLOW ? DENY : ALLOW;

        } else {

      ret = rc;

        }

    }

    alias_put(a);

    break;

      }

      FALLTHROUGH;

  case WORD:

      if (hostname_matches(shost, lhost, m->name) == ALLOW)

    ret = m->negated ? DENY : ALLOW;

      break;

    }

    sudo_debug_printf(SUDO_DEBUG_DEBUG,

  "host %s (%s) matches sudoers host %s%s: %s", lhost, shost,

  m->negated ? "!" : "", m->name ? m->name : "ALL",

  ret == ALLOW ? "ALLOW" : "DENY");

    debug_return_int(ret);

}

/*

 * Check for cmnd and args in a list of members.

 * Returns ALLOW, DENY or UNSPEC.

 */

int

cmndlist_matches(const struct sudoers_parse_tree *parse_tree,

    const struct member_list *list, const char *runchroot,

    struct cmnd_info *info)

{

    struct member *m;

    int matched;

    debug_decl(cmndlist_matches, SUDOERS_DEBUG_MATCH);

    TAILQ_FOREACH_REVERSE(m, list, member_list, entries) {

  matched = cmnd_matches(parse_tree, m, runchroot, info);

  if (SPECIFIED(matched))

      debug_return_int(matched);

    }

    debug_return_int(UNSPEC);

}

/*

 * Check cmnd and args.

 * Returns ALLOW, DENY or UNSPEC.

 */

int

cmnd_matches(const struct sudoers_parse_tree *parse_tree,

    const struct member *m, const char *runchroot, struct cmnd_info *info)

{

    struct alias *a;

    struct sudo_command *c;

    int rc, matched = UNSPEC;

    debug_decl(cmnd_matches, SUDOERS_DEBUG_MATCH);

    switch (m->type) {

  case ALL:

  case COMMAND:

      c = (struct sudo_command *)m->name;

      if (command_matches(parse_tree->ctx, c->cmnd, c->args, runchroot,

        info, &c->digests) == ALLOW)

    matched = m->negated ? DENY : ALLOW;

      break;

  case ALIAS:

      a = alias_get(parse_tree, m->name, CMNDALIAS);

      if (a != NULL) {

    rc = cmndlist_matches(parse_tree, &a->members, runchroot, info);

    if (SPECIFIED(rc)) {

        if (m->negated) {

      matched = rc == ALLOW ? DENY : ALLOW;

        } else {

      matched = rc;

        }

    }

    alias_put(a);

      }

      break;

    }

    debug_return_int(matched);

}

/*

 * Like cmnd_matches() but only matches against the ALL command.

 * Returns ALLOW, DENY or UNSPEC.

 */

int

cmnd_matches_all(const struct sudoers_parse_tree *parse_tree,

    const struct member *m, const char *runchroot, struct cmnd_info *info)

{

    const bool negated = m->negated;

    struct sudo_command *c;

    int matched = UNSPEC;

    struct alias *a;

    debug_decl(cmnd_matches_all, SUDOERS_DEBUG_MATCH);

    switch (m->type) {

  case ALL:

      c = (struct sudo_command *)m->name;

      if (command_matches(parse_tree->ctx, c->cmnd, c->args, runchroot,

        info, &c->digests) == ALLOW)

    matched = negated ? DENY : ALLOW;

      break;

  case ALIAS:

      a = alias_get(parse_tree, m->name, CMNDALIAS);

      if (a != NULL) {

    TAILQ_FOREACH_REVERSE(m, &a->members, member_list, entries) {

        matched = cmnd_matches_all(parse_tree, m, runchroot, info);

        if (SPECIFIED(matched)) {

      if (negated)

          matched = matched == ALLOW ? DENY : ALLOW;

      break;

        }

    }

    alias_put(a);

      }

      break;

    }

    debug_return_int(matched);

}

/*

 * Returns ALLOW if the hostname matches the pattern, else DENY

 */

int

hostname_matches(const char *shost, const char *lhost, const char *pattern)

{

    const char *host;

    int ret;

    debug_decl(hostname_matches, SUDOERS_DEBUG_MATCH);

    host = strchr(pattern, '.') != NULL ? lhost : shost;

    ret = DENY;

    if (has_meta(pattern)) {

  if (fnmatch(pattern, host, FNM_CASEFOLD) == 0)

      ret = ALLOW;

    } else {

  if (strcasecmp(host, pattern) == 0)

      ret = ALLOW;

    }

    debug_return_int(ret);

}

/*

 * Returns ALLOW if the user/uid from sudoers matches the specified user/uid,

 * else returns DENY.

 */

int

userpw_matches(const char *sudoers_user, const char *user, const struct passwd *pw)

{

    const char *errstr;

    int ret = DENY;

    uid_t uid;

    debug_decl(userpw_matches, SUDOERS_DEBUG_MATCH);

    if (pw != NULL && *sudoers_user == '#') {

  uid = (uid_t) sudo_strtoid(sudoers_user + 1, &errstr);

  if (errstr == NULL && uid == pw->pw_uid) {

      ret = ALLOW;

      goto done;

  }

    }

    if (def_case_insensitive_user) {

  if (strcasecmp(sudoers_user, user) == 0)

      ret = ALLOW;

    } else {

  if (strcmp(sudoers_user, user) == 0)

      ret = ALLOW;

    }

done:

    sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,

  "user %s matches sudoers user %s: %s",

  user, sudoers_user, ret == ALLOW ? "ALLOW" : "DENY");

    debug_return_int(ret);

}

/*

 * Returns ALLOW if the group/gid from sudoers matches the specified group/gid,

 * else returns DENY.

 */

int

group_matches(const char *sudoers_group, const struct group *gr)

{

    const char *errstr;

    int ret = DENY;

    gid_t gid;

    debug_decl(group_matches, SUDOERS_DEBUG_MATCH);

    if (*sudoers_group == '#') {

  gid = (gid_t) sudo_strtoid(sudoers_group + 1, &errstr);

  if (errstr == NULL && gid == gr->gr_gid) {

      ret = ALLOW;

      goto done;

  }

    }

    if (def_case_insensitive_group) {

  if (strcasecmp(sudoers_group, gr->gr_name) == 0)

      ret = ALLOW;

    } else {

  if (strcmp(sudoers_group, gr->gr_name) == 0)

      ret = ALLOW;

    }

done:

    sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,

  "group %s matches sudoers group %s: %s",

  gr->gr_name, sudoers_group, ret == ALLOW ? "ALLOW" : "DENY");

    debug_return_int(ret);

}

/*

 * Returns true if the given user belongs to the named group,

 * else returns false.

 */

int

usergr_matches(const char *group, const char *user, const struct passwd *pw)

{

    struct passwd *pw0 = NULL;

    int ret = DENY;

    debug_decl(usergr_matches, SUDOERS_DEBUG_MATCH);

    /* Make sure we have a valid usergroup, sudo style */

    if (*group++ != '%') {

  sudo_debug_printf(SUDO_DEBUG_DIAG, "user group %s has no leading '%%'",

      group);

  goto done;

    }

    /* Query group plugin for %:name groups. */

    if (*group == ':' && def_group_plugin) {

  if (group_plugin_query(user, group + 1, pw) == true)

      ret = ALLOW;

  goto done;

    }

    /* Look up user's primary gid in the passwd file. */

    if (pw == NULL) {

  if ((pw0 = sudo_getpwnam(user)) == NULL) {

      sudo_debug_printf(SUDO_DEBUG_DIAG, "unable to find %s in passwd db",

    user);

      goto done;

  }

  pw = pw0;

    }

    if (user_in_group(pw, group)) {

  ret = ALLOW;

  goto done;

    }

    /* Query the group plugin for Unix groups too? */

    if (def_group_plugin && def_always_query_group_plugin) {

  if (group_plugin_query(user, group, pw) == true) {

      ret = ALLOW;

      goto done;

  }

    }

done:

    if (pw0 != NULL)

  sudo_pw_delref(pw0);

    sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,

  "user %s matches group %s: %s", user, group,

  ret == ALLOW ? "ALLOW" : "DENY");

    debug_return_int(ret);

}

#if defined(HAVE_GETDOMAINNAME) || defined(SI_SRPC_DOMAIN)

/*

 * Check the domain for invalid characters.

 * Linux getdomainname(2) returns (none) if no domain is set.

 */

static bool

valid_domain(const char *domain)

{

    const char *cp;

    debug_decl(valid_domain, SUDOERS_DEBUG_MATCH);

    for (cp = domain; *cp != '\0'; cp++) {

  /* Check for illegal characters, Linux may use "(none)". */

  if (*cp == '(' || *cp == ')' || *cp == ',' || *cp == ' ')

      break;

    }

    if (cp == domain || *cp != '\0')

  debug_return_bool(false);

    debug_return_bool(true);

}

/*

 * Get NIS-style domain name and copy from static storage or NULL if none.

 */

const char *

sudo_getdomainname(void)

{

    static char *domain;

    static bool initialized;

    debug_decl(sudo_getdomainname, SUDOERS_DEBUG_MATCH);

    if (!initialized) {

  const size_t host_name_max = sudo_host_name_max();

  int rc;

  domain = malloc(host_name_max + 1);

  if (domain != NULL) {

      domain[0] = '\0';

# ifdef SI_SRPC_DOMAIN

      rc = sysinfo(SI_SRPC_DOMAIN, domain, host_name_max + 1);

# else

      rc = getdomainname(domain, host_name_max + 1);

# endif

      if (rc == -1 || !valid_domain(domain)) {

    /* Error or invalid domain name. */

    free(domain);

    domain = NULL;

      }

  } else {

      /* XXX - want to pass error back to caller */

      sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,

    "unable to allocate memory");

  }

  initialized = true;

    }

    debug_return_str(domain);

}

#else

const char *

sudo_getdomainname(void)

{

    debug_decl(sudo_getdomainname, SUDOERS_DEBUG_MATCH);

    debug_return_ptr(NULL);

}

#endif /* HAVE_GETDOMAINNAME || SI_SRPC_DOMAIN */

/*

 * Returns ALLOW if "host" and "user" belong to the netgroup "netgr",

 * else return DENY.  Either of "lhost", "shost" or "user" may be NULL

 * in which case that argument is not checked...

 */

int

netgr_matches(const struct sudo_nss *nss, const char *netgr,

    const char *lhost, const char *shost, const char *user)

{

    const char *domain;

    int ret = DENY;

    debug_decl(netgr_matches, SUDOERS_DEBUG_MATCH);

    if (!def_use_netgroups) {

  sudo_debug_printf(SUDO_DEBUG_INFO, "netgroups are disabled");

  debug_return_int(DENY);

    }

    /* make sure we have a valid netgroup, sudo style */

    if (*netgr++ != '+') {

  sudo_debug_printf(SUDO_DEBUG_DIAG, "netgroup %s has no leading '+'",

      netgr);

  debug_return_int(DENY);

    }

    /* get the domain name (if any) */

    domain = sudo_getdomainname();

    /* Use nss-specific innetgr() function if available. */

    if (nss != NULL && nss->innetgr != NULL) {

  switch (nss->innetgr(nss, netgr, lhost, user, domain)) {

  case 0:

      if (lhost != shost) {

    if (nss->innetgr(nss, netgr, shost, user, domain) == 1)

        ret = ALLOW;

      }

      goto done;

  case 1:

      ret = ALLOW;

      goto done;

  default:

      /* Not supported, use system innetgr(3). */

      break;

  }

    }

#ifdef HAVE_INNETGR

    /* Use system innetgr() function. */

    if (innetgr(netgr, lhost, user, domain) == 1) {

  ret = ALLOW;

    } else if (lhost != shost) {

  if (innetgr(netgr, shost, user, domain) == 1)

      ret = ALLOW;

    }

#else

    sudo_debug_printf(SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO,

  "%s: no system netgroup support", __func__);

#endif /* HAVE_INNETGR */

done:

    sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,

  "netgroup %s matches (%s|%s, %s, %s): %s", netgr, lhost ? lhost : "",

  shost ? shost : "", user ? user : "", domain ? domain : "",

  ret == ALLOW ? "ALLOW" : "DENY");

    debug_return_int(ret);

}