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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 07:24:22 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 07:24:22 +0000 |
commit | 45d6379135504814ab723b57f0eb8be23393a51d (patch) | |
tree | d4f2ec4acca824a8446387a758b0ce4238a4dffa /lib/irs/resconf.c | |
parent | Initial commit. (diff) | |
download | bind9-45d6379135504814ab723b57f0eb8be23393a51d.tar.xz bind9-45d6379135504814ab723b57f0eb8be23393a51d.zip |
Adding upstream version 1:9.16.44.upstream/1%9.16.44upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | lib/irs/resconf.c | 689 |
1 files changed, 689 insertions, 0 deletions
diff --git a/lib/irs/resconf.c b/lib/irs/resconf.c new file mode 100644 index 0000000..f3b7be5 --- /dev/null +++ b/lib/irs/resconf.c @@ -0,0 +1,689 @@ +/* + * Copyright (C) Internet Systems Consortium, Inc. ("ISC") + * + * SPDX-License-Identifier: MPL-2.0 + * + * 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/. + * + * See the COPYRIGHT file distributed with this work for additional + * information regarding copyright ownership. + */ + +/*! \file resconf.c */ + +/** + * Module for parsing resolv.conf files (largely derived from lwconfig.c). + * + * irs_resconf_load() opens the file filename and parses it to initialize + * the configuration structure. + * + * \section lwconfig_return Return Values + * + * irs_resconf_load() returns #IRS_R_SUCCESS if it successfully read and + * parsed filename. It returns a non-0 error code if filename could not be + * opened or contained incorrect resolver statements. + * + * \section lwconfig_see See Also + * + * stdio(3), \link resolver resolver \endlink + * + * \section files Files + * + * /etc/resolv.conf + */ + +#ifndef WIN32 +#include <netdb.h> +#include <sys/socket.h> +#include <sys/types.h> +#endif /* ifndef WIN32 */ + +#include <ctype.h> +#include <errno.h> +#include <inttypes.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include <isc/magic.h> +#include <isc/mem.h> +#include <isc/netaddr.h> +#include <isc/sockaddr.h> +#include <isc/util.h> + +#include <irs/netdb.h> +#include <irs/resconf.h> + +#define IRS_RESCONF_MAGIC ISC_MAGIC('R', 'E', 'S', 'c') +#define IRS_RESCONF_VALID(c) ISC_MAGIC_VALID(c, IRS_RESCONF_MAGIC) + +/*! + * protocol constants + */ + +#if !defined(NS_INADDRSZ) +#define NS_INADDRSZ 4 +#endif /* if !defined(NS_INADDRSZ) */ + +#if !defined(NS_IN6ADDRSZ) +#define NS_IN6ADDRSZ 16 +#endif /* if !defined(NS_IN6ADDRSZ) */ + +/*! + * resolv.conf parameters + */ + +#define RESCONFMAXNAMESERVERS 3U /*%< max 3 "nameserver" entries */ +#define RESCONFMAXSEARCH 8U /*%< max 8 domains in "search" entry */ +#define RESCONFMAXLINELEN 256U /*%< max size of a line */ +#define RESCONFMAXSORTLIST 10U /*%< max 10 */ + +/*! + * configuration data structure + */ + +struct irs_resconf { + /* + * The configuration data is a thread-specific object, and does not + * need to be locked. + */ + unsigned int magic; + isc_mem_t *mctx; + + isc_sockaddrlist_t nameservers; + unsigned int numns; /*%< number of configured servers + * */ + + char *domainname; + char *search[RESCONFMAXSEARCH]; + uint8_t searchnxt; /*%< index for next free slot + * */ + + irs_resconf_searchlist_t searchlist; + + struct { + isc_netaddr_t addr; + /*% mask has a non-zero 'family' if set */ + isc_netaddr_t mask; + } sortlist[RESCONFMAXSORTLIST]; + uint8_t sortlistnxt; + + /*%< non-zero if 'options debug' set */ + uint8_t resdebug; + /*%< set to n in 'options ndots:n' */ + uint8_t ndots; +}; + +static isc_result_t +resconf_parsenameserver(irs_resconf_t *conf, FILE *fp); +static isc_result_t +resconf_parsedomain(irs_resconf_t *conf, FILE *fp); +static isc_result_t +resconf_parsesearch(irs_resconf_t *conf, FILE *fp); +static isc_result_t +resconf_parsesortlist(irs_resconf_t *conf, FILE *fp); +static isc_result_t +resconf_parseoption(irs_resconf_t *ctx, FILE *fp); + +#if HAVE_GET_WIN32_NAMESERVERS +static isc_result_t +get_win32_nameservers(irs_resconf_t *conf); +#endif /* if HAVE_GET_WIN32_NAMESERVERS */ + +/*! + * Eat characters from FP until EOL or EOF. Returns EOF or '\n' + */ +static int +eatline(FILE *fp) { + int ch; + + ch = fgetc(fp); + while (ch != '\n' && ch != EOF) { + ch = fgetc(fp); + } + + return (ch); +} + +/*! + * Eats white space up to next newline or non-whitespace character (of + * EOF). Returns the last character read. Comments are considered white + * space. + */ +static int +eatwhite(FILE *fp) { + int ch; + + ch = fgetc(fp); + while (ch != '\n' && ch != EOF && isspace((unsigned char)ch)) { + ch = fgetc(fp); + } + + if (ch == ';' || ch == '#') { + ch = eatline(fp); + } + + return (ch); +} + +/*! + * Skip over any leading whitespace and then read in the next sequence of + * non-whitespace characters. In this context newline is not considered + * whitespace. Returns EOF on end-of-file, or the character + * that caused the reading to stop. + */ +static int +getword(FILE *fp, char *buffer, size_t size) { + int ch; + char *p; + + REQUIRE(buffer != NULL); + REQUIRE(size > 0U); + + p = buffer; + *p = '\0'; + + ch = eatwhite(fp); + + if (ch == EOF) { + return (EOF); + } + + do { + *p = '\0'; + + if (ch == EOF || isspace((unsigned char)ch)) { + break; + } else if ((size_t)(p - buffer) == size - 1) { + return (EOF); /* Not enough space. */ + } + + *p++ = (char)ch; + ch = fgetc(fp); + } while (1); + + return (ch); +} + +static isc_result_t +add_server(isc_mem_t *mctx, const char *address_str, + isc_sockaddrlist_t *nameservers) { + int error; + isc_sockaddr_t *address = NULL; + struct addrinfo hints, *res; + isc_result_t result = ISC_R_SUCCESS; + + res = NULL; + memset(&hints, 0, sizeof(hints)); + hints.ai_family = AF_UNSPEC; + hints.ai_socktype = SOCK_DGRAM; + hints.ai_protocol = IPPROTO_UDP; + hints.ai_flags = AI_NUMERICHOST; + error = getaddrinfo(address_str, "53", &hints, &res); + if (error != 0) { + return (ISC_R_BADADDRESSFORM); + } + + /* XXX: special case: treat all-0 IPv4 address as loopback */ + if (res->ai_family == AF_INET) { + struct in_addr *v4; + unsigned char zeroaddress[] = { 0, 0, 0, 0 }; + unsigned char loopaddress[] = { 127, 0, 0, 1 }; + + v4 = &((struct sockaddr_in *)res->ai_addr)->sin_addr; + if (memcmp(v4, zeroaddress, 4) == 0) { + memmove(v4, loopaddress, 4); + } + } + + address = isc_mem_get(mctx, sizeof(*address)); + if (res->ai_addrlen > sizeof(address->type)) { + isc_mem_put(mctx, address, sizeof(*address)); + result = ISC_R_RANGE; + goto cleanup; + } + address->length = (unsigned int)res->ai_addrlen; + memmove(&address->type.ss, res->ai_addr, res->ai_addrlen); + ISC_LINK_INIT(address, link); + ISC_LIST_APPEND(*nameservers, address, link); + +cleanup: + freeaddrinfo(res); + + return (result); +} + +static isc_result_t +create_addr(const char *buffer, isc_netaddr_t *addr, int convert_zero) { + struct in_addr v4; + struct in6_addr v6; + + if (inet_pton(AF_INET, buffer, &v4) == 1) { + if (convert_zero) { + unsigned char zeroaddress[] = { 0, 0, 0, 0 }; + unsigned char loopaddress[] = { 127, 0, 0, 1 }; + if (memcmp(&v4, zeroaddress, 4) == 0) { + memmove(&v4, loopaddress, 4); + } + } + addr->family = AF_INET; + memmove(&addr->type.in, &v4, NS_INADDRSZ); + addr->zone = 0; + } else if (inet_pton(AF_INET6, buffer, &v6) == 1) { + addr->family = AF_INET6; + memmove(&addr->type.in6, &v6, NS_IN6ADDRSZ); + addr->zone = 0; + } else { + return (ISC_R_BADADDRESSFORM); /* Unrecognised format. */ + } + + return (ISC_R_SUCCESS); +} + +static isc_result_t +resconf_parsenameserver(irs_resconf_t *conf, FILE *fp) { + char word[RESCONFMAXLINELEN]; + int cp; + isc_result_t result; + + cp = getword(fp, word, sizeof(word)); + if (strlen(word) == 0U) { + return (ISC_R_UNEXPECTEDEND); /* Nothing on line. */ + } else if (cp == ' ' || cp == '\t') { + cp = eatwhite(fp); + } + + if (cp != EOF && cp != '\n') { + return (ISC_R_UNEXPECTEDTOKEN); /* Extra junk on line. */ + } + + if (conf->numns == RESCONFMAXNAMESERVERS) { + return (ISC_R_SUCCESS); + } + + result = add_server(conf->mctx, word, &conf->nameservers); + if (result != ISC_R_SUCCESS) { + return (result); + } + conf->numns++; + + return (ISC_R_SUCCESS); +} + +static isc_result_t +resconf_parsedomain(irs_resconf_t *conf, FILE *fp) { + char word[RESCONFMAXLINELEN]; + int res; + unsigned int i; + + res = getword(fp, word, sizeof(word)); + if (strlen(word) == 0U) { + return (ISC_R_UNEXPECTEDEND); /* Nothing else on line. */ + } else if (res == ' ' || res == '\t') { + res = eatwhite(fp); + } + + if (res != EOF && res != '\n') { + return (ISC_R_UNEXPECTEDTOKEN); /* Extra junk on line. */ + } + + if (conf->domainname != NULL) { + isc_mem_free(conf->mctx, conf->domainname); + } + + /* + * Search and domain are mutually exclusive. + */ + for (i = 0; i < RESCONFMAXSEARCH; i++) { + if (conf->search[i] != NULL) { + isc_mem_free(conf->mctx, conf->search[i]); + conf->search[i] = NULL; + } + } + conf->searchnxt = 0; + + conf->domainname = isc_mem_strdup(conf->mctx, word); + + return (ISC_R_SUCCESS); +} + +static isc_result_t +resconf_parsesearch(irs_resconf_t *conf, FILE *fp) { + int delim; + unsigned int idx; + char word[RESCONFMAXLINELEN]; + + if (conf->domainname != NULL) { + /* + * Search and domain are mutually exclusive. + */ + isc_mem_free(conf->mctx, conf->domainname); + conf->domainname = NULL; + } + + /* + * Remove any previous search definitions. + */ + for (idx = 0; idx < RESCONFMAXSEARCH; idx++) { + if (conf->search[idx] != NULL) { + isc_mem_free(conf->mctx, conf->search[idx]); + conf->search[idx] = NULL; + } + } + conf->searchnxt = 0; + + delim = getword(fp, word, sizeof(word)); + if (strlen(word) == 0U) { + return (ISC_R_UNEXPECTEDEND); /* Nothing else on line. */ + } + + idx = 0; + while (strlen(word) > 0U) { + if (conf->searchnxt == RESCONFMAXSEARCH) { + goto ignore; /* Too many domains. */ + } + + INSIST(idx < sizeof(conf->search) / sizeof(conf->search[0])); + conf->search[idx] = isc_mem_strdup(conf->mctx, word); + idx++; + conf->searchnxt++; + + ignore: + if (delim == EOF || delim == '\n') { + break; + } else { + delim = getword(fp, word, sizeof(word)); + } + } + + return (ISC_R_SUCCESS); +} + +static isc_result_t +resconf_parsesortlist(irs_resconf_t *conf, FILE *fp) { + int delim, res; + unsigned int idx; + char word[RESCONFMAXLINELEN]; + char *p; + + delim = getword(fp, word, sizeof(word)); + if (strlen(word) == 0U) { + return (ISC_R_UNEXPECTEDEND); /* Empty line after keyword. */ + } + + while (strlen(word) > 0U) { + if (conf->sortlistnxt == RESCONFMAXSORTLIST) { + return (ISC_R_QUOTA); /* Too many values. */ + } + + p = strchr(word, '/'); + if (p != NULL) { + *p++ = '\0'; + } + + idx = conf->sortlistnxt; + INSIST(idx < + sizeof(conf->sortlist) / sizeof(conf->sortlist[0])); + res = create_addr(word, &conf->sortlist[idx].addr, 1); + if (res != ISC_R_SUCCESS) { + return (res); + } + + if (p != NULL) { + res = create_addr(p, &conf->sortlist[idx].mask, 0); + if (res != ISC_R_SUCCESS) { + return (res); + } + } else { + /* + * Make up a mask. (XXX: is this correct?) + */ + conf->sortlist[idx].mask = conf->sortlist[idx].addr; + memset(&conf->sortlist[idx].mask.type, 0xff, + sizeof(conf->sortlist[idx].mask.type)); + } + + conf->sortlistnxt++; + + if (delim == EOF || delim == '\n') { + break; + } else { + delim = getword(fp, word, sizeof(word)); + } + } + + return (ISC_R_SUCCESS); +} + +static isc_result_t +resconf_parseoption(irs_resconf_t *conf, FILE *fp) { + int delim; + long ndots; + char *p; + char word[RESCONFMAXLINELEN]; + + delim = getword(fp, word, sizeof(word)); + if (strlen(word) == 0U) { + return (ISC_R_UNEXPECTEDEND); /* Empty line after keyword. */ + } + + while (strlen(word) > 0U) { + if (strcmp("debug", word) == 0) { + conf->resdebug = 1; + } else if (strncmp("ndots:", word, 6) == 0) { + ndots = strtol(word + 6, &p, 10); + if (*p != '\0') { /* Bad string. */ + return (ISC_R_UNEXPECTEDTOKEN); + } + if (ndots < 0 || ndots > 0xff) { /* Out of range. */ + return (ISC_R_RANGE); + } + conf->ndots = (uint8_t)ndots; + } + + if (delim == EOF || delim == '\n') { + break; + } else { + delim = getword(fp, word, sizeof(word)); + } + } + + return (ISC_R_SUCCESS); +} + +static isc_result_t +add_search(irs_resconf_t *conf, char *domain) { + irs_resconf_search_t *entry; + + entry = isc_mem_get(conf->mctx, sizeof(*entry)); + + entry->domain = domain; + ISC_LINK_INIT(entry, link); + ISC_LIST_APPEND(conf->searchlist, entry, link); + + return (ISC_R_SUCCESS); +} + +/*% parses a file and fills in the data structure. */ +isc_result_t +irs_resconf_load(isc_mem_t *mctx, const char *filename, irs_resconf_t **confp) { + FILE *fp = NULL; + char word[256]; + isc_result_t rval, ret = ISC_R_SUCCESS; + irs_resconf_t *conf; + unsigned int i; + int stopchar; + + REQUIRE(mctx != NULL); + REQUIRE(filename != NULL); + REQUIRE(strlen(filename) > 0U); + REQUIRE(confp != NULL && *confp == NULL); + + conf = isc_mem_get(mctx, sizeof(*conf)); + + conf->mctx = mctx; + ISC_LIST_INIT(conf->nameservers); + ISC_LIST_INIT(conf->searchlist); + conf->numns = 0; + conf->domainname = NULL; + conf->searchnxt = 0; + conf->sortlistnxt = 0; + conf->resdebug = 0; + conf->ndots = 1; + for (i = 0; i < RESCONFMAXSEARCH; i++) { + conf->search[i] = NULL; + } + + errno = 0; + if ((fp = fopen(filename, "r")) != NULL) { + do { + stopchar = getword(fp, word, sizeof(word)); + if (stopchar == EOF) { + rval = ISC_R_SUCCESS; + POST(rval); + break; + } + + if (strlen(word) == 0U) { + rval = ISC_R_SUCCESS; + } else if (strcmp(word, "nameserver") == 0) { + rval = resconf_parsenameserver(conf, fp); + } else if (strcmp(word, "domain") == 0) { + rval = resconf_parsedomain(conf, fp); + } else if (strcmp(word, "search") == 0) { + rval = resconf_parsesearch(conf, fp); + } else if (strcmp(word, "sortlist") == 0) { + rval = resconf_parsesortlist(conf, fp); + } else if (strcmp(word, "options") == 0) { + rval = resconf_parseoption(conf, fp); + } else { + /* unrecognised word. Ignore entire line */ + rval = ISC_R_SUCCESS; + stopchar = eatline(fp); + if (stopchar == EOF) { + break; + } + } + if (ret == ISC_R_SUCCESS && rval != ISC_R_SUCCESS) { + ret = rval; + } + } while (1); + + fclose(fp); + } else { + switch (errno) { + case ENOENT: + break; + default: + isc_mem_put(mctx, conf, sizeof(*conf)); + return (ISC_R_INVALIDFILE); + } + } + + if (ret != ISC_R_SUCCESS) { + goto error; + } + + /* + * Construct unified search list from domain or configured + * search list + */ + if (conf->domainname != NULL) { + ret = add_search(conf, conf->domainname); + } else if (conf->searchnxt > 0) { + for (i = 0; i < conf->searchnxt; i++) { + ret = add_search(conf, conf->search[i]); + if (ret != ISC_R_SUCCESS) { + break; + } + } + } + +#if HAVE_GET_WIN32_NAMESERVERS + ret = get_win32_nameservers(conf); + if (ret != ISC_R_SUCCESS) { + goto error; + } +#endif /* if HAVE_GET_WIN32_NAMESERVERS */ + + /* If we don't find a nameserver fall back to localhost */ + if (conf->numns == 0U) { + INSIST(ISC_LIST_EMPTY(conf->nameservers)); + + /* XXX: should we catch errors? */ + (void)add_server(conf->mctx, "::1", &conf->nameservers); + (void)add_server(conf->mctx, "127.0.0.1", &conf->nameservers); + } + +error: + conf->magic = IRS_RESCONF_MAGIC; + + if (ret != ISC_R_SUCCESS) { + irs_resconf_destroy(&conf); + } else { + if (fp == NULL) { + ret = ISC_R_FILENOTFOUND; + } + *confp = conf; + } + + return (ret); +} + +void +irs_resconf_destroy(irs_resconf_t **confp) { + irs_resconf_t *conf; + isc_sockaddr_t *address; + irs_resconf_search_t *searchentry; + unsigned int i; + + REQUIRE(confp != NULL); + conf = *confp; + *confp = NULL; + REQUIRE(IRS_RESCONF_VALID(conf)); + + while ((searchentry = ISC_LIST_HEAD(conf->searchlist)) != NULL) { + ISC_LIST_UNLINK(conf->searchlist, searchentry, link); + isc_mem_put(conf->mctx, searchentry, sizeof(*searchentry)); + } + + while ((address = ISC_LIST_HEAD(conf->nameservers)) != NULL) { + ISC_LIST_UNLINK(conf->nameservers, address, link); + isc_mem_put(conf->mctx, address, sizeof(*address)); + } + + if (conf->domainname != NULL) { + isc_mem_free(conf->mctx, conf->domainname); + } + + for (i = 0; i < RESCONFMAXSEARCH; i++) { + if (conf->search[i] != NULL) { + isc_mem_free(conf->mctx, conf->search[i]); + } + } + + isc_mem_put(conf->mctx, conf, sizeof(*conf)); +} + +isc_sockaddrlist_t * +irs_resconf_getnameservers(irs_resconf_t *conf) { + REQUIRE(IRS_RESCONF_VALID(conf)); + + return (&conf->nameservers); +} + +irs_resconf_searchlist_t * +irs_resconf_getsearchlist(irs_resconf_t *conf) { + REQUIRE(IRS_RESCONF_VALID(conf)); + + return (&conf->searchlist); +} + +unsigned int +irs_resconf_getndots(irs_resconf_t *conf) { + REQUIRE(IRS_RESCONF_VALID(conf)); + + return ((unsigned int)conf->ndots); +} |