/* Copyright (C) 1996-2016 Free Software Foundation, Inc. This file is part of the GNU C Library. Extended from original form by Ulrich Drepper , 1996. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, see . */ /* Parts of this file are plain copies of the file `getnetnamadr.c' from the bind package and it has the following copyright. */ /* Copyright (c) 1993 Carlos Leandro and Rui Salgueiro * Dep. Matematica Universidade de Coimbra, Portugal, Europe * * 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. */ /* * Copyright (c) 1983, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include #include #include #include #include #include #include #include "nsswitch.h" #include /* Maximum number of aliases we allow. */ #define MAX_NR_ALIASES 48 #if PACKETSZ > 65536 # define MAXPACKET PACKETSZ #else # define MAXPACKET 65536 #endif typedef enum { BYADDR, BYNAME } lookup_method; /* We need this time later. */ typedef union querybuf { HEADER hdr; u_char buf[MAXPACKET]; } querybuf; /* These functions are defined in res_comp.c. */ #define NS_MAXCDNAME 255 /* maximum compressed domain name */ extern int __ns_name_ntop (const u_char *, char *, size_t) __THROW; extern int __ns_name_unpack (const u_char *, const u_char *, const u_char *, u_char *, size_t) __THROW; /* Prototypes for local functions. */ static enum nss_status getanswer_r (const querybuf *answer, int anslen, struct netent *result, char *buffer, size_t buflen, int *errnop, int *h_errnop, lookup_method net_i); enum nss_status _nss_dns_getnetbyname_r (const char *name, struct netent *result, char *buffer, size_t buflen, int *errnop, int *herrnop) { /* Return entry for network with NAME. */ union { querybuf *buf; u_char *ptr; } net_buffer; querybuf *orig_net_buffer; int anslen; enum nss_status status; if (__res_maybe_init (&_res, 0) == -1) return NSS_STATUS_UNAVAIL; net_buffer.buf = orig_net_buffer = (querybuf *) alloca (1024); anslen = __libc_res_nsearch (&_res, name, C_IN, T_PTR, net_buffer.buf->buf, 1024, &net_buffer.ptr, NULL, NULL, NULL, NULL); if (anslen < 0) { /* Nothing found. */ *errnop = errno; if (net_buffer.buf != orig_net_buffer) free (net_buffer.buf); return (errno == ECONNREFUSED || errno == EPFNOSUPPORT || errno == EAFNOSUPPORT) ? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND; } status = getanswer_r (net_buffer.buf, anslen, result, buffer, buflen, errnop, herrnop, BYNAME); if (net_buffer.buf != orig_net_buffer) free (net_buffer.buf); return status; } enum nss_status _nss_dns_getnetbyaddr_r (uint32_t net, int type, struct netent *result, char *buffer, size_t buflen, int *errnop, int *herrnop) { /* Return entry for network with NAME. */ enum nss_status status; union { querybuf *buf; u_char *ptr; } net_buffer; querybuf *orig_net_buffer; unsigned int net_bytes[4]; char qbuf[MAXDNAME]; int cnt, anslen; u_int32_t net2; int olderr = errno; /* No net address lookup for IPv6 yet. */ if (type != AF_INET) return NSS_STATUS_UNAVAIL; if (__res_maybe_init (&_res, 0) == -1) return NSS_STATUS_UNAVAIL; net2 = (u_int32_t) net; for (cnt = 4; net2 != 0; net2 >>= 8) net_bytes[--cnt] = net2 & 0xff; switch (cnt) { case 3: /* Class A network. */ sprintf (qbuf, "0.0.0.%u.in-addr.arpa", net_bytes[3]); break; case 2: /* Class B network. */ sprintf (qbuf, "0.0.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2]); break; case 1: /* Class C network. */ sprintf (qbuf, "0.%u.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2], net_bytes[1]); break; case 0: /* Class D - E network. */ sprintf (qbuf, "%u.%u.%u.%u.in-addr.arpa", net_bytes[3], net_bytes[2], net_bytes[1], net_bytes[0]); break; } net_buffer.buf = orig_net_buffer = (querybuf *) alloca (1024); anslen = __libc_res_nquery (&_res, qbuf, C_IN, T_PTR, net_buffer.buf->buf, 1024, &net_buffer.ptr, NULL, NULL, NULL, NULL); if (anslen < 0) { /* Nothing found. */ int err = errno; __set_errno (olderr); if (net_buffer.buf != orig_net_buffer) free (net_buffer.buf); return (err == ECONNREFUSED || err == EPFNOSUPPORT || err == EAFNOSUPPORT) ? NSS_STATUS_UNAVAIL : NSS_STATUS_NOTFOUND; } status = getanswer_r (net_buffer.buf, anslen, result, buffer, buflen, errnop, herrnop, BYADDR); if (net_buffer.buf != orig_net_buffer) free (net_buffer.buf); if (status == NSS_STATUS_SUCCESS) { /* Strip trailing zeros. */ unsigned int u_net = net; /* Maybe net should be unsigned? */ while ((u_net & 0xff) == 0 && u_net != 0) u_net >>= 8; result->n_net = u_net; } return status; } #undef offsetof #define offsetof(Type, Member) ((size_t) &((Type *) NULL)->Member) static enum nss_status getanswer_r (const querybuf *answer, int anslen, struct netent *result, char *buffer, size_t buflen, int *errnop, int *h_errnop, lookup_method net_i) { /* * Find first satisfactory answer * * answer --> +------------+ ( MESSAGE ) * | Header | * +------------+ * | Question | the question for the name server * +------------+ * | Answer | RRs answering the question * +------------+ * | Authority | RRs pointing toward an authority * | Additional | RRs holding additional information * +------------+ */ struct net_data { char *aliases[MAX_NR_ALIASES]; char linebuffer[0]; } *net_data; uintptr_t pad = -(uintptr_t) buffer % __alignof__ (struct net_data); buffer += pad; if (__glibc_unlikely (buflen < sizeof (*net_data) + pad)) { /* The buffer is too small. */ too_small: *errnop = ERANGE; *h_errnop = NETDB_INTERNAL; return NSS_STATUS_TRYAGAIN; } buflen -= pad; net_data = (struct net_data *) buffer; int linebuflen = buflen - offsetof (struct net_data, linebuffer); if (buflen - offsetof (struct net_data, linebuffer) != linebuflen) linebuflen = INT_MAX; const unsigned char *end_of_message = &answer->buf[anslen]; const HEADER *header_pointer = &answer->hdr; /* #/records in the answer section. */ int answer_count = ntohs (header_pointer->ancount); /* #/entries in the question section. */ int question_count = ntohs (header_pointer->qdcount); char *bp = net_data->linebuffer; const unsigned char *cp = &answer->buf[HFIXEDSZ]; char **alias_pointer; int have_answer; u_char packtmp[NS_MAXCDNAME]; if (question_count == 0) { /* FIXME: the Sun version uses for host name lookup an additional parameter for pointing to h_errno. this is missing here. OSF/1 has a per-thread h_errno variable. */ if (header_pointer->aa != 0) { __set_h_errno (HOST_NOT_FOUND); return NSS_STATUS_NOTFOUND; } else { __set_h_errno (TRY_AGAIN); return NSS_STATUS_TRYAGAIN; } } /* Skip the question part. */ while (question_count-- > 0) { int n = __dn_skipname (cp, end_of_message); if (n < 0 || end_of_message - (cp + n) < QFIXEDSZ) { __set_h_errno (NO_RECOVERY); return NSS_STATUS_UNAVAIL; } cp += n + QFIXEDSZ; } alias_pointer = result->n_aliases = &net_data->aliases[0]; *alias_pointer = NULL; have_answer = 0; while (--answer_count >= 0 && cp < end_of_message) { int n = dn_expand (answer->buf, end_of_message, cp, bp, linebuflen); int type, class; n = __ns_name_unpack (answer->buf, end_of_message, cp, packtmp, sizeof packtmp); if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1) { if (errno == EMSGSIZE) goto too_small; n = -1; } if (n > 0 && bp[0] == '.') bp[0] = '\0'; if (n < 0 || res_dnok (bp) == 0) break; cp += n; GETSHORT (type, cp); GETSHORT (class, cp); cp += INT32SZ; /* TTL */ GETSHORT (n, cp); if (class == C_IN && type == T_PTR) { n = __ns_name_unpack (answer->buf, end_of_message, cp, packtmp, sizeof packtmp); if (n != -1 && __ns_name_ntop (packtmp, bp, linebuflen) == -1) { if (errno == EMSGSIZE) goto too_small; n = -1; } if (n < 0 || !res_hnok (bp)) { /* XXX What does this mean? The original form from bind returns NULL. Incrementing cp has no effect in any case. What should I return here. ??? */ cp += n; return NSS_STATUS_UNAVAIL; } cp += n; if (alias_pointer + 2 < &net_data->aliases[MAX_NR_ALIASES]) { *alias_pointer++ = bp; n = strlen (bp) + 1; bp += n; linebuflen -= n; result->n_addrtype = class == C_IN ? AF_INET : AF_UNSPEC; ++have_answer; } } } if (have_answer) { *alias_pointer = NULL; switch (net_i) { case BYADDR: result->n_name = *result->n_aliases++; result->n_net = 0L; return NSS_STATUS_SUCCESS; case BYNAME: { char **ap; for (ap = result->n_aliases; *ap != NULL; ++ap) { /* Check each alias name for being of the forms: 4.3.2.1.in-addr.arpa = net 1.2.3.4 3.2.1.in-addr.arpa = net 0.1.2.3 2.1.in-addr.arpa = net 0.0.1.2 1.in-addr.arpa = net 0.0.0.1 */ uint32_t val = 0; /* Accumulator for n_net value. */ unsigned int shift = 0; /* Which part we are parsing now. */ const char *p = *ap; /* Consuming the string. */ do { /* Match the leading 0 or 0[xX] base indicator. */ unsigned int base = 10; if (*p == '0' && p[1] != '.') { base = 8; ++p; if (*p == 'x' || *p == 'X') { base = 16; ++p; if (*p == '.') break; /* No digit here. Give up on alias. */ } if (*p == '\0') break; } uint32_t part = 0; /* Accumulates this part's number. */ do { if (isdigit (*p) && (*p - '0' < base)) part = (part * base) + (*p - '0'); else if (base == 16 && isxdigit (*p)) part = (part << 4) + 10 + (tolower (*p) - 'a'); ++p; } while (*p != '\0' && *p != '.'); if (*p != '.') break; /* Bad form. Give up on this name. */ /* Install this as the next more significant byte. */ val |= part << shift; shift += 8; ++p; /* If we are out of digits now, there are two cases: 1. We are done with digits and now see "in-addr.arpa". 2. This is not the droid we are looking for. */ if (!isdigit (*p) && !strcasecmp (p, "in-addr.arpa")) { result->n_net = val; return NSS_STATUS_SUCCESS; } /* Keep going when we have seen fewer than 4 parts. */ } while (shift < 32); } } break; } } __set_h_errno (TRY_AGAIN); return NSS_STATUS_TRYAGAIN; }