/* $NetBSD: dlz_filesystem_dynamic.c,v 1.7.2.1 2023/08/11 13:43:30 martin Exp $ */ /* * Copyright (C) Internet Systems Consortium, Inc. ("ISC") * * SPDX-License-Identifier: MPL-2.0 and ISC * * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, you can obtain one at https://mozilla.org/MPL/2.0/. */ /* * Copyright (C) 2002 Stichting NLnet, Netherlands, stichting@nlnet.nl. * * The development of Dynamically Loadable Zones (DLZ) for Bind 9 was * conceived and contributed by Rob Butler. * * 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. */ /* * This provides the externally loadable filesystem DLZ module, without * update support */ #include #include #include #include #include #include #include "dir.h" #include "dlz_list.h" #include "dlz_minimal.h" typedef struct config_data { char *basedir; int basedirsize; char *datadir; int datadirsize; char *xfrdir; int xfrdirsize; int splitcnt; char separator; char pathsep; /* Helper functions from the dlz_dlopen driver */ log_t *log; dns_sdlz_putrr_t *putrr; dns_sdlz_putnamedrr_t *putnamedrr; dns_dlz_writeablezone_t *writeable_zone; } config_data_t; typedef struct dir_entry dir_entry_t; struct dir_entry { char dirpath[DIR_PATHMAX]; DLZ_LINK(dir_entry_t) link; }; typedef DLZ_LIST(dir_entry_t) dlist_t; /* forward reference */ static void b9_add_helper(struct config_data *cd, const char *helper_name, void *ptr); /* * Private methods */ static bool is_safe(const char *input) { unsigned int i; unsigned int len = strlen(input); /* check that only allowed characters are in the domain name */ for (i = 0; i < len; i++) { /* '.' is allowed, but has special requirements */ if (input[i] == '.') { /* '.' is not allowed as first char */ if (i == 0) { return (false); } /* '..', two dots together is not allowed. */ if (input[i - 1] == '.') { return (false); } /* '.' is not allowed as last char */ if (i == len - 1) { return (false); } /* only 1 dot in ok location, continue at next char */ continue; } /* '-' is allowed, continue at next char */ if (input[i] == '-') { continue; } /* 0-9 is allowed, continue at next char */ if (input[i] >= '0' && input[i] <= '9') { continue; } /* A-Z uppercase is allowed, continue at next char */ if (input[i] >= 'A' && input[i] <= 'Z') { continue; } /* a-z lowercase is allowed, continue at next char */ if (input[i] >= 'a' && input[i] <= 'z') { continue; } /* * colon needs to be allowed for IPV6 client * addresses. Not dangerous in domain names, as not a * special char. */ if (input[i] == ':') { continue; } /* * '@' needs to be allowed for in zone data. Not * dangerous in domain names, as not a special char. */ if (input[i] == '@') { continue; } /* * if we reach this point we have encountered a * disallowed char! */ return (false); } /* everything ok. */ return (true); } static isc_result_t create_path_helper(char *out, const char *in, config_data_t *cd) { char *tmpString; char *tmpPtr; int i; tmpString = strdup(in); if (tmpString == NULL) { return (ISC_R_NOMEMORY); } /* * don't forget is_safe guarantees '.' will NOT be the * first/last char */ while ((tmpPtr = strrchr(tmpString, '.')) != NULL) { i = 0; while (tmpPtr[i + 1] != '\0') { if (cd->splitcnt < 1) { strcat(out, (char *)&tmpPtr[i + 1]); } else { strncat(out, (char *)&tmpPtr[i + 1], cd->splitcnt); } strncat(out, (char *)&cd->pathsep, 1); if (cd->splitcnt == 0) { break; } if (strlen((char *)&tmpPtr[i + 1]) <= (unsigned int)cd->splitcnt) { break; } i += cd->splitcnt; } tmpPtr[0] = '\0'; } /* handle the "first" label properly */ i = 0; tmpPtr = tmpString; while (tmpPtr[i] != '\0') { if (cd->splitcnt < 1) { strcat(out, (char *)&tmpPtr[i]); } else { strncat(out, (char *)&tmpPtr[i], cd->splitcnt); } strncat(out, (char *)&cd->pathsep, 1); if (cd->splitcnt == 0) { break; } if (strlen((char *)&tmpPtr[i]) <= (unsigned int)cd->splitcnt) { break; } i += cd->splitcnt; } free(tmpString); return (ISC_R_SUCCESS); } /*% * Checks to make sure zone and host are safe. If safe, then * hashes zone and host strings to build a path. If zone / host * are not safe an error is returned. */ static isc_result_t create_path(const char *zone, const char *host, const char *client, config_data_t *cd, char **path) { char *tmpPath; int pathsize; int len; isc_result_t result; bool isroot = false; /* special case for root zone */ if (strcmp(zone, ".") == 0) { isroot = true; } /* if the requested zone is "unsafe", return error */ if (!isroot && !is_safe(zone)) { return (ISC_R_FAILURE); } /* if host was passed, verify that it is safe */ if (host != NULL && !is_safe(host)) { return (ISC_R_FAILURE); } /* if client was passed, verify that it is safe */ if (client != NULL && !is_safe(client)) { return (ISC_R_FAILURE); } /* Determine how much memory the split up string will require */ if (host != NULL) { len = strlen(zone) + strlen(host); } else if (client != NULL) { len = strlen(zone) + strlen(client); } else { len = strlen(zone); } /* * even though datadir and xfrdir will never be in the same * string we only waste a few bytes by allocating for both, * and then we are safe from buffer overruns. */ pathsize = len + cd->basedirsize + cd->datadirsize + cd->xfrdirsize + 4; /* if we are splitting names, we will need extra space. */ if (cd->splitcnt > 0) { pathsize += len / cd->splitcnt; } tmpPath = malloc(pathsize * sizeof(char)); if (tmpPath == NULL) { /* write error message */ cd->log(ISC_LOG_ERROR, "Filesystem driver unable to " "allocate memory in create_path()."); result = ISC_R_NOMEMORY; goto cleanup_mem; } /* * build path string. * start out with base directory. */ strcpy(tmpPath, cd->basedir); /* add zone name - parsed properly */ if (!isroot) { result = create_path_helper(tmpPath, zone, cd); if (result != ISC_R_SUCCESS) { goto cleanup_mem; } } /* * When neither client or host is passed we are building a * path to see if a zone is supported. We require that a zone * path have the "data dir" directory contained within it so * that we know this zone is really supported. Otherwise, * this zone may not really be supported because we are * supporting a delagated sub zone. * * Example: * * We are supporting long.domain.com and using a splitcnt of * 0. the base dir is "/base-dir/" and the data dir is * "/.datadir" We want to see if we are authoritative for * domain.com. Path /base-dir/com/domain/.datadir since * /base-dir/com/domain/.datadir does not exist, we are not * authoritative for the domain "domain.com". However we are * authoritative for the domain "long.domain.com" because the * path /base-dir/com/domain/long/.datadir does exist! */ /* if client is passed append xfr dir, otherwise append data dir */ if (client != NULL) { strcat(tmpPath, cd->xfrdir); strncat(tmpPath, (char *)&cd->pathsep, 1); strcat(tmpPath, client); } else { strcat(tmpPath, cd->datadir); } /* if host not null, add it. */ if (host != NULL) { strncat(tmpPath, (char *)&cd->pathsep, 1); result = create_path_helper(tmpPath, host, cd); if (result != ISC_R_SUCCESS) { goto cleanup_mem; } } /* return the path we built. */ *path = tmpPath; /* return success */ result = ISC_R_SUCCESS; cleanup_mem: /* cleanup memory */ /* free tmpPath memory */ if (tmpPath != NULL && result != ISC_R_SUCCESS) { free(tmpPath); } return (result); } static isc_result_t process_dir(dir_t *dir, void *passback, config_data_t *cd, dlist_t *dir_list, unsigned int basedirlen) { char tmp[DIR_PATHMAX + DIR_NAMEMAX]; int astPos; struct stat sb; isc_result_t result = ISC_R_FAILURE; char *endp; char *type; char *ttlStr; char *data; char host[DIR_NAMEMAX]; char *tmpString; char *tmpPtr; int ttl; int i; int len; dir_entry_t *direntry; bool foundHost; tmp[0] = '\0'; /* set 1st byte to '\0' so strcpy works right. */ host[0] = '\0'; foundHost = false; /* copy base directory name to tmp. */ strcpy(tmp, dir->dirname); /* dir->dirname will always have '*' as the last char. */ astPos = strlen(dir->dirname) - 1; /* if dir_list != NULL, were are performing a zone xfr */ if (dir_list != NULL) { /* if splitcnt == 0, determine host from path. */ if (cd->splitcnt == 0) { if (strlen(tmp) - 3 > basedirlen) { tmp[astPos - 1] = '\0'; tmpString = (char *)&tmp[basedirlen + 1]; /* handle filesystem's special wildcard "-" */ if (strcmp(tmpString, "-") == 0) { strcpy(host, "*"); } else { /* * not special wildcard -- normal name */ while ((tmpPtr = strrchr( tmpString, cd->pathsep)) != NULL) { if ((strlen(host) + strlen(tmpPtr + 1) + 2) > DIR_NAMEMAX) { continue; } strcat(host, tmpPtr + 1); strcat(host, "."); tmpPtr[0] = '\0'; } if ((strlen(host) + strlen(tmpString) + 1) <= DIR_NAMEMAX) { strcat(host, tmpString); } } foundHost = true; /* set tmp again for use later */ strcpy(tmp, dir->dirname); } } else { /* * if splitcnt != 0 determine host from * ".host" directory entry */ while (dir_read(dir) == ISC_R_SUCCESS) { if (strncasecmp(".host", dir->entry.name, 5) == 0) { /* * handle filesystem's special * wildcard "-" */ if (strcmp((char *)&dir->entry.name[6], "-") == 0) { strcpy(host, "*"); } else { strncpy(host, (char *)&dir->entry .name[6], sizeof(host) - 1); host[255] = '\0'; } foundHost = true; break; } } /* reset dir list for use later */ dir_reset(dir); } /* end of else */ } while (dir_read(dir) == ISC_R_SUCCESS) { cd->log(ISC_LOG_DEBUG(1), "Filesystem driver Dir name:" " '%s' Dir entry: '%s'\n", dir->dirname, dir->entry.name); /* skip any entries starting with "." */ if (dir->entry.name[0] == '.') { continue; } /* * get rid of '*', set to NULL. Effectively trims * string from previous loop to base directory only * while still leaving memory for concat to be * performed next. */ tmp[astPos] = '\0'; /* add name to base directory name. */ strcat(tmp, dir->entry.name); /* make sure we can stat entry */ if (stat(tmp, &sb) == 0) { /* if entry is a directory */ if ((sb.st_mode & S_IFDIR) != 0) { /* * if dir list is NOT NULL, add dir to * dir list */ if (dir_list != NULL) { direntry = malloc(sizeof(dir_entry_t)); if (direntry == NULL) { return (ISC_R_NOMEMORY); } strcpy(direntry->dirpath, tmp); DLZ_LINK_INIT(direntry, link); DLZ_LIST_APPEND(*dir_list, direntry, link); result = ISC_R_SUCCESS; } continue; /* * if entry is a file be sure we do * not add entry to DNS results if we * are performing a zone xfr and we * could not find a host entry. */ } else if (dir_list != NULL && !foundHost) { continue; } } else { /* if we cannot stat entry, skip it. */ continue; } type = dir->entry.name; ttlStr = strchr(type, cd->separator); if (ttlStr == NULL) { cd->log(ISC_LOG_ERROR, "Filesystem driver: " "%s could not be parsed properly", tmp); return (ISC_R_FAILURE); } /* replace separator char with NULL to split string */ ttlStr[0] = '\0'; /* start string after NULL of previous string */ ttlStr = (char *)&ttlStr[1]; data = strchr(ttlStr, cd->separator); if (data == NULL) { cd->log(ISC_LOG_ERROR, "Filesystem driver: " "%s could not be parsed properly", tmp); return (ISC_R_FAILURE); } /* replace separator char with NULL to split string */ data[0] = '\0'; /* start string after NULL of previous string */ data = (char *)&data[1]; /* replace all cd->separator chars with a space. */ len = strlen(data); for (i = 0; i < len; i++) { if (data[i] == cd->separator) { data[i] = ' '; } } /* convert text to int, make sure it worked right */ ttl = strtol(ttlStr, &endp, 10); if (*endp != '\0' || ttl < 0) { cd->log(ISC_LOG_ERROR, "Filesystem driver " "ttl must be a positive number"); } /* pass data back to Bind */ if (dir_list == NULL) { result = cd->putrr((dns_sdlzlookup_t *)passback, type, ttl, data); } else { result = cd->putnamedrr((dns_sdlzallnodes_t *)passback, (char *)host, type, ttl, data); } /* if error, return error right away */ if (result != ISC_R_SUCCESS) { return (result); } } /* end of while loop */ return (result); } /* * DLZ methods */ isc_result_t dlz_allowzonexfr(void *dbdata, const char *name, const char *client) { isc_result_t result; char *path; struct stat sb; config_data_t *cd; path = NULL; cd = (config_data_t *)dbdata; if (create_path(name, NULL, client, cd, &path) != ISC_R_SUCCESS) { return (ISC_R_NOTFOUND); } if (stat(path, &sb) != 0) { result = ISC_R_NOTFOUND; goto complete_AXFR; } if ((sb.st_mode & S_IFREG) != 0) { result = ISC_R_SUCCESS; goto complete_AXFR; } result = ISC_R_NOTFOUND; complete_AXFR: free(path); return (result); } isc_result_t dlz_allnodes(const char *zone, void *dbdata, dns_sdlzallnodes_t *allnodes) { isc_result_t result; dlist_t *dir_list; config_data_t *cd = (config_data_t *)dbdata; char *basepath; unsigned int basepathlen; struct stat sb; dir_t dir; dir_entry_t *dir_entry; dir_entry_t *next_de; basepath = NULL; /* allocate memory for list */ dir_list = malloc(sizeof(dlist_t)); if (dir_list == NULL) { result = ISC_R_NOTFOUND; goto complete_allnds; } /* initialize list */ DLZ_LIST_INIT(*dir_list); if (create_path(zone, NULL, NULL, cd, &basepath) != ISC_R_SUCCESS) { result = ISC_R_NOTFOUND; goto complete_allnds; } /* remove path separator at end of path so stat works properly */ basepathlen = strlen(basepath); if (stat(basepath, &sb) != 0) { result = ISC_R_NOTFOUND; goto complete_allnds; } if ((sb.st_mode & S_IFDIR) == 0) { result = ISC_R_NOTFOUND; goto complete_allnds; } /* initialize and open directory */ dir_init(&dir); result = dir_open(&dir, basepath); /* if directory open failed, return error. */ if (result != ISC_R_SUCCESS) { cd->log(ISC_LOG_ERROR, "Unable to open %s directory to read entries.", basepath); result = ISC_R_FAILURE; goto complete_allnds; } /* process the directory */ result = process_dir(&dir, allnodes, cd, dir_list, basepathlen); /* close the directory */ dir_close(&dir); if (result != ISC_R_SUCCESS) { goto complete_allnds; } /* get first dir entry from list. */ dir_entry = DLZ_LIST_HEAD(*dir_list); while (dir_entry != NULL) { result = dir_open(&dir, dir_entry->dirpath); /* if directory open failed, return error. */ if (result != ISC_R_SUCCESS) { cd->log(ISC_LOG_ERROR, "Unable to open %s " "directory to read entries.", basepath); result = ISC_R_FAILURE; goto complete_allnds; } /* process the directory */ result = process_dir(&dir, allnodes, cd, dir_list, basepathlen); /* close the directory */ dir_close(&dir); if (result != ISC_R_SUCCESS) { goto complete_allnds; } dir_entry = DLZ_LIST_NEXT(dir_entry, link); } /* end while */ complete_allnds: if (dir_list != NULL) { /* clean up entries from list. */ dir_entry = DLZ_LIST_HEAD(*dir_list); while (dir_entry != NULL) { next_de = DLZ_LIST_NEXT(dir_entry, link); free(dir_entry); dir_entry = next_de; } /* end while */ free(dir_list); } if (basepath != NULL) { free(basepath); } return (result); } #if DLZ_DLOPEN_VERSION < 3 isc_result_t dlz_findzonedb(void *dbdata, const char *name) #else /* if DLZ_DLOPEN_VERSION < 3 */ isc_result_t dlz_findzonedb(void *dbdata, const char *name, dns_clientinfomethods_t *methods, dns_clientinfo_t *clientinfo) #endif /* if DLZ_DLOPEN_VERSION < 3 */ { isc_result_t result; config_data_t *cd = (config_data_t *)dbdata; char *path; struct stat sb; path = NULL; #if DLZ_DLOPEN_VERSION >= 3 UNUSED(methods); UNUSED(clientinfo); #endif /* if DLZ_DLOPEN_VERSION >= 3 */ if (create_path(name, NULL, NULL, cd, &path) != ISC_R_SUCCESS) { return (ISC_R_NOTFOUND); } cd->log(ISC_LOG_DEBUG(1), "Filesystem driver Findzone() Checking for path: '%s'\n", path); if (stat(path, &sb) != 0) { result = ISC_R_NOTFOUND; goto complete_FZ; } if ((sb.st_mode & S_IFDIR) != 0) { result = ISC_R_SUCCESS; goto complete_FZ; } result = ISC_R_NOTFOUND; complete_FZ: free(path); return (result); } #if DLZ_DLOPEN_VERSION == 1 isc_result_t dlz_lookup(const char *zone, const char *name, void *dbdata, dns_sdlzlookup_t *lookup) #else /* if DLZ_DLOPEN_VERSION == 1 */ isc_result_t dlz_lookup(const char *zone, const char *name, void *dbdata, dns_sdlzlookup_t *lookup, dns_clientinfomethods_t *methods, dns_clientinfo_t *clientinfo) #endif /* if DLZ_DLOPEN_VERSION == 1 */ { isc_result_t result = ISC_R_NOTFOUND; config_data_t *cd = (config_data_t *)dbdata; char *path; struct stat sb; dir_t dir; path = NULL; UNUSED(lookup); #if DLZ_DLOPEN_VERSION >= 2 UNUSED(methods); UNUSED(clientinfo); #endif /* if DLZ_DLOPEN_VERSION >= 2 */ if (strcmp(name, "*") == 0) { /* * handle filesystem's special wildcard "-" */ result = create_path(zone, "-", NULL, cd, &path); } else { result = create_path(zone, name, NULL, cd, &path); } if (result != ISC_R_SUCCESS) { return (ISC_R_NOTFOUND); } /* remove path separator at end of path so stat works properly */ path[strlen(path) - 1] = '\0'; cd->log(ISC_LOG_DEBUG(1), "Filesystem driver lookup() Checking for path: '%s'\n", path); if (stat(path, &sb) != 0) { result = ISC_R_NOTFOUND; goto complete_lkup; } if ((sb.st_mode & S_IFDIR) == 0) { result = ISC_R_NOTFOUND; goto complete_lkup; } /* initialize and open directory */ dir_init(&dir); result = dir_open(&dir, path); /* if directory open failed, return error. */ if (result != ISC_R_SUCCESS) { cd->log(ISC_LOG_ERROR, "Unable to open %s directory to read entries.", path); result = ISC_R_FAILURE; goto complete_lkup; } /* process any records in the directory */ result = process_dir(&dir, lookup, cd, NULL, 0); /* close the directory */ dir_close(&dir); complete_lkup: free(path); return (result); } isc_result_t dlz_create(const char *dlzname, unsigned int argc, char *argv[], void **dbdata, ...) { isc_result_t result = ISC_R_NOMEMORY; config_data_t *cd; char *endp; int len; char pathsep; const char *helper_name; va_list ap; UNUSED(dlzname); /* allocate memory for our config data and helper functions */ cd = calloc(1, sizeof(config_data_t)); if (cd == NULL) { goto no_mem; } /* zero the memory */ memset(cd, 0, sizeof(config_data_t)); /* Fill in the helper functions */ va_start(ap, dbdata); while ((helper_name = va_arg(ap, const char *)) != NULL) { b9_add_helper(cd, helper_name, va_arg(ap, void *)); } va_end(ap); /* we require 5 command line args. */ if (argc != 6) { cd->log(ISC_LOG_ERROR, "Filesystem driver requires " "6 command line args."); result = ISC_R_FAILURE; goto free_cd; } if (strlen(argv[5]) > 1) { cd->log(ISC_LOG_ERROR, "Filesystem driver can only " "accept a single character for " "separator."); result = ISC_R_FAILURE; goto free_cd; } /* verify base dir ends with '/' or '\' */ len = strlen(argv[1]); if (argv[1][len - 1] != '\\' && argv[1][len - 1] != '/') { cd->log(ISC_LOG_ERROR, "Base dir parameter for filesystem driver " "should end with %s", "either '/' or '\\' "); result = ISC_R_FAILURE; goto free_cd; } /* determine and save path separator for later */ if (argv[1][len - 1] == '\\') { pathsep = '\\'; } else { pathsep = '/'; } cd->pathsep = pathsep; /* get and store our base directory */ cd->basedir = strdup(argv[1]); if (cd->basedir == NULL) { goto no_mem; } cd->basedirsize = strlen(cd->basedir); /* get and store our data sub-dir */ cd->datadir = strdup(argv[2]); if (cd->datadir == NULL) { goto no_mem; } cd->datadirsize = strlen(cd->datadir); /* get and store our zone xfr sub-dir */ cd->xfrdir = strdup(argv[3]); if (cd->xfrdir == NULL) { goto no_mem; } cd->xfrdirsize = strlen(cd->xfrdir); /* get and store our directory split count */ cd->splitcnt = strtol(argv[4], &endp, 10); if (*endp != '\0' || cd->splitcnt < 0) { cd->log(ISC_LOG_ERROR, "Directory split count must be zero (0) " "or a positive number"); } /* get and store our separator character */ cd->separator = *argv[5]; /* pass back config data */ *dbdata = cd; /* return success */ return (ISC_R_SUCCESS); /* handle no memory error */ no_mem: /* write error message */ if (cd != NULL && cd->log != NULL) { cd->log(ISC_LOG_ERROR, "filesystem_dynamic: Filesystem driver " "unable to " "allocate memory for config data."); } free_cd: /* if we allocated a config data object clean it up */ if (cd != NULL) { dlz_destroy(cd); } /* return error */ return (result); } void dlz_destroy(void *dbdata) { config_data_t *cd; cd = (config_data_t *)dbdata; /* * free memory for each section of config data that was * allocated */ if (cd->basedir != NULL) { free(cd->basedir); } if (cd->datadir != NULL) { free(cd->datadir); } if (cd->xfrdir != NULL) { free(cd->xfrdir); } /* free config data memory */ free(cd); } /* * Return the version of the API */ int dlz_version(unsigned int *flags) { UNUSED(flags); return (DLZ_DLOPEN_VERSION); } /* * Register a helper function from the bind9 dlz_dlopen driver */ static void b9_add_helper(struct config_data *cd, const char *helper_name, void *ptr) { if (strcmp(helper_name, "log") == 0) { cd->log = (log_t *)ptr; } if (strcmp(helper_name, "putrr") == 0) { cd->putrr = (dns_sdlz_putrr_t *)ptr; } if (strcmp(helper_name, "putnamedrr") == 0) { cd->putnamedrr = (dns_sdlz_putnamedrr_t *)ptr; } if (strcmp(helper_name, "writeable_zone") == 0) { cd->writeable_zone = (dns_dlz_writeablezone_t *)ptr; } }