/* * nonlocal-group.c * group database for nss_nonlocal proxy * * Copyright © 2007 Anders Kaseorg and Tim Abbott * * * Permission is hereby granted, free of charge, to any person * obtaining a copy of this software and associated documentation * files (the "Software"), to deal in the Software without * restriction, including without limitation the rights to use, copy, * modify, merge, publish, distribute, sublicense, and/or sell copies * of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include #include #include "nsswitch-internal.h" #include "nonlocal.h" #define MAGIC_LOCAL_GR_BUFLEN (sysconf(_SC_GETGR_R_SIZE_MAX) + 7) #define MAGIC_NONLOCAL_GROUPNAME "nss-nonlocal-users" #define MAGIC_LOCAL_GROUPNAME "nss-local-users" static service_user * nss_group_nonlocal_database(void) { static service_user *nip = NULL; if (nip == NULL) __nss_database_lookup("group_nonlocal", NULL, "", &nip); return nip; } enum nss_status check_nonlocal_gid(const char *user, gid_t gid, int *errnop) { enum nss_status status = NSS_STATUS_SUCCESS; struct group gbuf; struct group *gbufp = &gbuf; int ret; int old_errno = errno; int buflen = MAGIC_LOCAL_GR_BUFLEN; char *buf = malloc(buflen); if (buf == NULL) { *errnop = ENOMEM; errno = old_errno; return NSS_STATUS_TRYAGAIN; } errno = 0; ret = getgrgid_r(gid, gbufp, buf, buflen, &gbufp); if (ret != 0) { *errnop = old_errno; status = NSS_STATUS_TRYAGAIN; } else if (gbufp != NULL) { syslog(LOG_WARNING, "nss_nonlocal: removing local group %u (%s) from non-local user %s\n", gbuf.gr_gid, gbuf.gr_name, user); status = NSS_STATUS_NOTFOUND; } free(buf); errno = old_errno; return status; } enum nss_status get_local_group(const char *name, struct group *grp, char *buffer, size_t buflen, int *errnop) { enum nss_status status = NSS_STATUS_NOTFOUND; struct group gbuf; struct group *gbufp = &gbuf; int ret; int old_errno = errno; int len = MAGIC_LOCAL_GR_BUFLEN; char *buf = malloc(len); if (buf == NULL) { *errnop = ENOMEM; errno = old_errno; return NSS_STATUS_TRYAGAIN; } errno = 0; ret = getgrnam_r(name, gbufp, buf, len, &gbufp); if (ret != 0) { *errnop = old_errno; status = NSS_STATUS_TRYAGAIN; } else if (gbufp != NULL) { status = NSS_STATUS_SUCCESS; grp->gr_name = strncpy(buffer, gbufp->gr_name, buflen); buffer = buffer + strlen(grp->gr_name); buflen = buflen - strlen(grp->gr_name); grp->gr_passwd = strncpy(buffer, gbufp->gr_passwd, buflen); buffer = buffer + strlen(grp->gr_passwd); buflen = buflen - strlen(grp->gr_passwd); grp->gr_gid = gbufp->gr_gid; if (buflen < sizeof(void *)) { *errnop = ERANGE; status = NSS_STATUS_TRYAGAIN; } else { grp->gr_mem = memset(buffer, 0, sizeof(void *)); } } free(buf); errno = old_errno; return status; } static service_user *grent_nip = NULL; static void *grent_fct_start; static union { enum nss_status (*l)(struct group *grp, char *buffer, size_t buflen, int *errnop); void *ptr; } grent_fct; static const char *grent_fct_name = "getgrent_r"; enum nss_status _nss_nonlocal_setgrent(int stayopen) { static const char *fct_name = "setgrent"; static void *fct_start = NULL; enum nss_status status; service_user *nip; union { enum nss_status (*l)(int stayopen); void *ptr; } fct; nip = nss_group_nonlocal_database(); if (nip == NULL) return NSS_STATUS_UNAVAIL; if (fct_start == NULL) fct_start = __nss_lookup_function(nip, fct_name); fct.ptr = fct_start; do { if (fct.ptr == NULL) status = NSS_STATUS_UNAVAIL; else status = DL_CALL_FCT(fct.l, (stayopen)); } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); if (status != NSS_STATUS_SUCCESS) return status; grent_nip = nip; if (grent_fct_start == NULL) grent_fct_start = __nss_lookup_function(nip, grent_fct_name); grent_fct.ptr = grent_fct_start; return NSS_STATUS_SUCCESS; } enum nss_status _nss_nonlocal_endgrent(void) { static const char *fct_name = "endgrent"; static void *fct_start = NULL; enum nss_status status; service_user *nip; union { enum nss_status (*l)(void); void *ptr; } fct; grent_nip = NULL; nip = nss_group_nonlocal_database(); if (nip == NULL) return NSS_STATUS_UNAVAIL; if (fct_start == NULL) fct_start = __nss_lookup_function(nip, fct_name); fct.ptr = fct_start; do { if (fct.ptr == NULL) status = NSS_STATUS_UNAVAIL; else status = DL_CALL_FCT(fct.l, ()); } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); return status; } enum nss_status _nss_nonlocal_getgrent_r(struct group *grp, char *buffer, size_t buflen, int *errnop) { enum nss_status status; if (grent_nip == NULL) { status = _nss_nonlocal_setgrent(0); if (status != NSS_STATUS_SUCCESS) return status; } do { if (grent_fct.ptr == NULL) status = NSS_STATUS_UNAVAIL; else { int nonlocal_errno; do status = DL_CALL_FCT(grent_fct.l, (grp, buffer, buflen, errnop)); while (status == NSS_STATUS_SUCCESS && check_nonlocal_gid("(unknown)", grp->gr_gid, &nonlocal_errno) != NSS_STATUS_SUCCESS); } if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) return status; if (status == NSS_STATUS_SUCCESS) return NSS_STATUS_SUCCESS; } while (__nss_next(&grent_nip, grent_fct_name, &grent_fct.ptr, status, 0) == 0); grent_nip = NULL; return NSS_STATUS_NOTFOUND; } enum nss_status _nss_nonlocal_getgrnam_r(const char *name, struct group *grp, char *buffer, size_t buflen, int *errnop) { static const char *fct_name = "getgrnam_r"; static void *fct_start = NULL; enum nss_status status; service_user *nip; union { enum nss_status (*l)(const char *name, struct group *grp, char *buffer, size_t buflen, int *errnop); void *ptr; } fct; if (buflen == MAGIC_LOCAL_GR_BUFLEN) return NSS_STATUS_UNAVAIL; nip = nss_group_nonlocal_database(); if (nip == NULL) return NSS_STATUS_UNAVAIL; if (fct_start == NULL) fct_start = __nss_lookup_function(nip, fct_name); fct.ptr = fct_start; do { if (fct.ptr == NULL) status = NSS_STATUS_UNAVAIL; else status = DL_CALL_FCT(fct.l, (name, grp, buffer, buflen, errnop)); if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) break; } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); if (status != NSS_STATUS_SUCCESS) return status; return check_nonlocal_gid(name, grp->gr_gid, errnop); } enum nss_status _nss_nonlocal_getgrgid_r(gid_t gid, struct group *grp, char *buffer, size_t buflen, int *errnop) { static const char *fct_name = "getgrgid_r"; static void *fct_start = NULL; enum nss_status status; service_user *nip; union { enum nss_status (*l)(gid_t gid, struct group *grp, char *buffer, size_t buflen, int *errnop); void *ptr; } fct; if (buflen == MAGIC_LOCAL_GR_BUFLEN) return NSS_STATUS_UNAVAIL; nip = nss_group_nonlocal_database(); if (nip == NULL) return NSS_STATUS_UNAVAIL; if (fct_start == NULL) fct_start = __nss_lookup_function(nip, fct_name); fct.ptr = fct_start; do { if (fct.ptr == NULL) status = NSS_STATUS_UNAVAIL; else status = DL_CALL_FCT(fct.l, (gid, grp, buffer, buflen, errnop)); if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) break; } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); if (status != NSS_STATUS_SUCCESS) return status; return check_nonlocal_gid(grp->gr_name, grp->gr_gid, errnop); } enum nss_status _nss_nonlocal_initgroups_dyn(const char *user, gid_t group, long int *start, long int *size, gid_t **groupsp, long int limit, int *errnop) { static const char *fct_name = "initgroups_dyn"; static void *fct_start = NULL; enum nss_status status; service_user *nip; union { enum nss_status (*l)(const char *user, gid_t group, long int *start, long int *size, gid_t **groupsp, long int limit, int *errnop); void *ptr; } fct; int in = *start, out = *start, i; gid_t local_users_gid; int is_local = 0; // Check that the user is a nonlocal user before adding any groups status = check_nonlocal_user(user, errnop); if (status == NSS_STATUS_NOTFOUND) { is_local = 1; } else if (status != NSS_STATUS_SUCCESS) { return status; } int buflen = sysconf(_SC_GETGR_R_SIZE_MAX); char *buffer = malloc(buflen); if (buffer == NULL) { *errnop = ENOMEM; return NSS_STATUS_TRYAGAIN; } struct group local_users_group; status = get_local_group(MAGIC_LOCAL_GROUPNAME, &local_users_group, buffer, buflen, errnop); free(buffer); if (status == NSS_STATUS_NOTFOUND) { syslog(LOG_WARNING, "nss_nonlocal: Group %s does not exist locally!", MAGIC_LOCAL_GROUPNAME); local_users_gid = 0; } else if (status == NSS_STATUS_SUCCESS) { if (is_local == 1) { // add the (local) user to the magic local users group, and finish (*groupsp)[out++] = local_users_group.gr_gid; syslog(LOG_DEBUG, "nss_nonlocal: Added %s to special group %s", user, MAGIC_LOCAL_GROUPNAME); *start = out; return NSS_STATUS_SUCCESS; } else { local_users_gid = local_users_group.gr_gid; } } else { return status; } nip = nss_group_nonlocal_database(); if (nip == NULL) return NSS_STATUS_UNAVAIL; if (fct_start == NULL) fct_start = __nss_lookup_function(nip, fct_name); fct.ptr = fct_start; do { if (fct.ptr == NULL) status = NSS_STATUS_UNAVAIL; else status = DL_CALL_FCT(fct.l, (user, group, start, size, groupsp, limit, errnop)); if (status == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) break; } while (__nss_next(&nip, fct_name, &fct.ptr, status, 0) == 0); if (status != NSS_STATUS_SUCCESS) return status; for (; in < *start; ++in) { int nonlocal_errno = *errnop; for (i = 0; i < out; ++i) if ((*groupsp)[i] == (*groupsp)[in]) break; if (i < out) continue; status = check_nonlocal_gid(user, (*groupsp)[in], &nonlocal_errno); if (status == NSS_STATUS_SUCCESS) { // Don't let users get into MAGIC_LOCAL_GROUPNAME from nonlocal reasons. if ((*groupsp)[in] == local_users_gid) { syslog(LOG_WARNING, "nss_nonlocal: Nonlocal user %s removed from special local users group %s", user, MAGIC_LOCAL_GROUPNAME); } else { (*groupsp)[out++] = (*groupsp)[in]; } } else if (status != NSS_STATUS_NOTFOUND) { *start = out; *errnop = nonlocal_errno; return status; } } // add the (nonlocal) user to the magic nonlocal users group buflen = sysconf(_SC_GETGR_R_SIZE_MAX); buffer = malloc(buflen); if (buffer == NULL) { *errnop = ENOMEM; return NSS_STATUS_TRYAGAIN; } struct group nonlocal_users_group; status = get_local_group(MAGIC_NONLOCAL_GROUPNAME, &nonlocal_users_group, buffer, buflen, errnop); if (status == NSS_STATUS_NOTFOUND) { syslog(LOG_WARNING, "nss_nonlocal: (local) group %s does not exist!", MAGIC_NONLOCAL_GROUPNAME); } else if (status == NSS_STATUS_SUCCESS) { (*groupsp)[out++] = nonlocal_users_group.gr_gid; syslog(LOG_DEBUG, "nss_nonlocal: Added %s to special group %s", user, MAGIC_NONLOCAL_GROUPNAME); } free(buffer); *start = out; return NSS_STATUS_SUCCESS; }