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v1.9.14
plugins/sudoers/match.c
763 строки
20 KB
Todd C. Miller
runaslist_matches: split out user_list and group_list matching.
14 июн 2023, 05:13
14 июн 2023, 05:13
78e65e1
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/* * SPDX-License-Identifier: ISC * * Copyright (c) 1996, 1998-2005, 2007-2023 * 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 char *lhost = parse_tree->lhost ? parse_tree->lhost : user_runhost; const char *shost = parse_tree->shost ? parse_tree->shost : user_srunhost; int matched = UNSPEC; struct alias *a; debug_decl(user_matches, SUDOERS_DEBUG_MATCH); switch (m->type) { case ALL: matched = !m->negated; break; case NETGROUP: if (netgr_matches(parse_tree->nss, m->name, def_netgroup_tuple ? lhost : NULL, def_netgroup_tuple ? shost : NULL, pw->pw_name)) matched = !m->negated; break; case USERGROUP: if (usergr_matches(m->name, pw->pw_name, pw)) matched = !m->negated; break; case ALIAS: if ((a = alias_get(parse_tree, m->name, USERALIAS)) != NULL) { /* XXX */ int rc = userlist_matches(parse_tree, pw, &a->members); if (rc != UNSPEC) matched = m->negated ? !rc : rc; alias_put(a); break; } FALLTHROUGH; case WORD: if (userpw_matches(m->name, pw->pw_name, pw)) matched = !m->negated; 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) { if ((matched = user_matches(parse_tree, pw, m)) != UNSPEC) break; } debug_return_int(matched); } struct gid_list * runas_getgroups(void) { const struct passwd *pw; debug_decl(runas_getgroups, SUDOERS_DEBUG_MATCH); if (def_preserve_groups) { sudo_gidlist_addref(user_gid_list); debug_return_ptr(user_gid_list); } /* Only use results from a group db query, not the front end. */ pw = runas_pw ? runas_pw : sudo_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, struct member **matching_user) { const char *lhost = parse_tree->lhost ? parse_tree->lhost : user_runhost; const char *shost = parse_tree->shost ? parse_tree->shost : user_srunhost; 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; break; case NETGROUP: if (netgr_matches(parse_tree->nss, m->name, def_netgroup_tuple ? lhost : NULL, def_netgroup_tuple ? shost : NULL, runas_pw->pw_name)) user_matched = !m->negated; break; case USERGROUP: if (usergr_matches(m->name, runas_pw->pw_name, runas_pw)) user_matched = !m->negated; break; case ALIAS: a = alias_get(parse_tree, m->name, RUNASALIAS); if (a != NULL) { const int rc = runas_userlist_matches(parse_tree, &a->members, matching_user); if (rc != UNSPEC) user_matched = m->negated ? !rc : rc; alias_put(a); break; } FALLTHROUGH; case WORD: if (userpw_matches(m->name, runas_pw->pw_name, runas_pw)) user_matched = !m->negated; break; case MYSELF: if (!ISSET(sudo_user.flags, RUNAS_USER_SPECIFIED) || strcmp(user_name, runas_pw->pw_name) == 0) user_matched = !m->negated; break; } if (user_matched != UNSPEC) { if (matching_user != NULL && m->type != ALIAS) *matching_user = m; 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, struct member **matching_group) { 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; break; case ALIAS: a = alias_get(parse_tree, m->name, RUNASALIAS); if (a != NULL) { const int rc = runas_grouplist_matches(parse_tree, &a->members, matching_group); if (rc != UNSPEC) group_matched = m->negated ? !rc : rc; alias_put(a); break; } FALLTHROUGH; case WORD: if (group_matches(m->name, runas_gr)) group_matched = !m->negated; break; } if (group_matched != UNSPEC) { if (matching_group != NULL && m->type != ALIAS) *matching_group = m; break; } } } if (group_matched == UNSPEC) { struct gid_list *runas_groups; /* * The runas group was not explicitly allowed by sudoers. * Check whether it is one of the target user's groups. */ if (runas_pw->pw_gid == runas_gr->gr_gid) { group_matched = ALLOW; /* runas group matches passwd db */ } else if ((runas_groups = runas_getgroups()) != NULL) { int i; for (i = 0; i < runas_groups->ngids; i++) { if (runas_groups->gids[i] == 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, struct member **matching_user, struct member **matching_group) { 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; matching_user = NULL; } user_matched = runas_userlist_matches(parse_tree, user_list, matching_user); if (ISSET(sudo_user.flags, RUNAS_GROUP_SPECIFIED)) { group_matched = runas_grouplist_matches(parse_tree, group_list, matching_group); } if (user_matched == DENY || group_matched == DENY) debug_return_int(DENY); if (user_matched == group_matched || 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 (matched != UNSPEC) break; } debug_return_int(matched); } /* * Check for user_runhost and user_srunhost 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 char *lhost = parse_tree->lhost ? parse_tree->lhost : user_runhost; const char *shost = parse_tree->shost ? parse_tree->shost : user_srunhost; 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 matched = UNSPEC; debug_decl(host_matches, SUDOERS_DEBUG_MATCH); switch (m->type) { case ALL: matched = !m->negated; break; case NETGROUP: if (netgr_matches(parse_tree->nss, m->name, lhost, shost, def_netgroup_tuple ? pw->pw_name : NULL)) matched = !m->negated; break; case NTWKADDR: if (addr_matches(m->name)) matched = !m->negated; break; case ALIAS: a = alias_get(parse_tree, m->name, HOSTALIAS); if (a != NULL) { /* XXX */ int rc = hostlist_matches_int(parse_tree, pw, lhost, shost, &a->members); if (rc != UNSPEC) matched = m->negated ? !rc : rc; alias_put(a); break; } FALLTHROUGH; case WORD: if (hostname_matches(shost, lhost, m->name)) matched = !m->negated; 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", matched == true ? "true" : "false"); debug_return_int(matched); } /* * 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 = UNSPEC; debug_decl(cmndlist_matches, SUDOERS_DEBUG_MATCH); TAILQ_FOREACH_REVERSE(m, list, member_list, entries) { matched = cmnd_matches(parse_tree, m, runchroot, info); if (matched != UNSPEC) break; } debug_return_int(matched); } /* * 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(c->cmnd, c->args, runchroot, info, &c->digests)) matched = !m->negated; break; case ALIAS: a = alias_get(parse_tree, m->name, CMNDALIAS); if (a != NULL) { rc = cmndlist_matches(parse_tree, &a->members, runchroot, info); if (rc != UNSPEC) matched = m->negated ? !rc : 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(c->cmnd, c->args, runchroot, info, &c->digests)) matched = !negated; 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 (matched != UNSPEC) { if (negated) matched = !matched; break; } } alias_put(a); } break; } debug_return_int(matched); } /* * Returns true if the hostname matches the pattern, else false */ bool hostname_matches(const char *shost, const char *lhost, const char *pattern) { const char *host; bool rc; debug_decl(hostname_matches, SUDOERS_DEBUG_MATCH); host = strchr(pattern, '.') != NULL ? lhost : shost; if (has_meta(pattern)) { rc = !fnmatch(pattern, host, FNM_CASEFOLD); } else { rc = !strcasecmp(host, pattern); } debug_return_bool(rc); } /* * Returns true if the user/uid from sudoers matches the specified user/uid, * else returns false. */ bool userpw_matches(const char *sudoers_user, const char *user, const struct passwd *pw) { const char *errstr; uid_t uid; bool rc; 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) { rc = true; goto done; } } if (def_case_insensitive_user) rc = strcasecmp(sudoers_user, user) == 0; else rc = strcmp(sudoers_user, user) == 0; done: sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO, "user %s matches sudoers user %s: %s", user, sudoers_user, rc ? "true" : "false"); debug_return_bool(rc); } /* * Returns true if the group/gid from sudoers matches the specified group/gid, * else returns false. */ bool group_matches(const char *sudoers_group, const struct group *gr) { const char *errstr; gid_t gid; bool rc; 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) { rc = true; goto done; } } if (def_case_insensitive_group) rc = strcasecmp(sudoers_group, gr->gr_name) == 0; else rc = strcmp(sudoers_group, gr->gr_name) == 0; done: sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO, "group %s matches sudoers group %s: %s", gr->gr_name, sudoers_group, rc ? "true" : "false"); debug_return_bool(rc); } /* * Returns true if the given user belongs to the named group, * else returns false. */ bool usergr_matches(const char *group, const char *user, const struct passwd *pw) { bool matched = false; struct passwd *pw0 = NULL; 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) matched = true; 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)) { matched = true; 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) { matched = true; 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, matched ? "true" : "false"); debug_return_bool(matched); } #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) { size_t host_name_max; int rc; # ifdef _SC_HOST_NAME_MAX host_name_max = (size_t)sysconf(_SC_HOST_NAME_MAX); if (host_name_max == (size_t)-1) # endif host_name_max = 255; /* POSIX and historic BSD */ 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 true if "host" and "user" belong to the netgroup "netgr", * else return false. Either of "lhost", "shost" or "user" may be NULL * in which case that argument is not checked... */ bool netgr_matches(const struct sudo_nss *nss, const char *netgr, const char *lhost, const char *shost, const char *user) { const char *domain; bool rc = false; debug_decl(netgr_matches, SUDOERS_DEBUG_MATCH); if (!def_use_netgroups) { sudo_debug_printf(SUDO_DEBUG_INFO, "netgroups are disabled"); debug_return_bool(false); } /* 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_bool(false); } /* 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) rc = true; } goto done; case 1: rc = true; goto done; default: /* Not supported, use system innetgr(3). */ break; } } #ifdef HAVE_INNETGR /* Use system innetgr() function. */ if (innetgr(netgr, lhost, user, domain) == 1) { rc = true; } else if (lhost != shost) { if (innetgr(netgr, shost, user, domain) == 1) rc = true; } #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 : "", rc ? "true" : "false"); debug_return_bool(rc); }