CVE-2015-5180: resolv: Fix crash with internal QTYPE [BZ #18784]
Also rename T_UNSPEC because an upcoming public header file update will use that name.
This commit is contained in:
Florian Weimer
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14
ChangeLog
14
ChangeLog
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@ -1,3 +1,17 @@
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2016-12-31 Florian Weimer <fweimer@redhat.com>
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[BZ #18784]
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CVE-2015-5180
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* include/arpa/nameser_compat.h (T_QUERY_A_AND_AAAA): Rename from
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T_UNSPEC. Adjust value.
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* resolv/nss_dns/dns-host.c (_nss_dns_gethostbyname4_r): Use it.
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* resolv/res_query.c (__libc_res_nquery): Likewise.
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* resolv/res_mkquery.c (res_nmkquery): Check for out-of-range
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QTYPEs.
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* resolv/tst-resolv-qtypes.c: New file.
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* resolv/Makefile (xtests): Add tst-resolv-qtypes.
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(tst-resolv-qtypes): Link against libresolv and libpthread.
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2016-12-31 Florian Weimer <fweimer@redhat.com>
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* elf/dl-tunables.h (__tunables_init): Fix unused attribute.
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8
NEWS
8
NEWS
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@ -191,12 +191,18 @@ Version 2.25
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Security related changes:
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On ARM EABI (32-bit), generating a backtrace for execution contexts which
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* On ARM EABI (32-bit), generating a backtrace for execution contexts which
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have been created with makecontext could fail to terminate due to a
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missing .cantunwind annotation. This has been observed to lead to a hang
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(denial of service) in some Go applications compiled with gccgo. Reported
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by Andreas Schwab. (CVE-2016-6323)
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* The DNS stub resolver functions would crash due to a NULL pointer
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dereference when processing a query with a valid DNS question type which
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was used internally in the implementation. The stub resolver now uses a
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question type which is outside the range of valid question type values.
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(CVE-2015-5180)
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The following bugs are resolved with this release:
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[The release manager will add the list generated by
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@ -3,9 +3,9 @@
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# ifndef _ISOMAC
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/* Picksome unused number to represent lookups of IPv4 and IPv6 (i.e.,
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T_A and T_AAAA). */
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#define T_UNSPEC 62321
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/* The number is outside the 16-bit RR type range and is used
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internally by the implementation. */
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#define T_QUERY_A_AND_AAAA 439963904
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# endif /* !_ISOMAC */
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#endif
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@ -49,6 +49,8 @@ tests += \
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tst-resolv-network \
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tst-resolv-search \
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# This test sends millions of packets and is rather slow.
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xtests += tst-resolv-qtypes
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endif
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extra-libs-others = $(extra-libs)
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libresolv-routines := res_comp res_debug \
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@ -123,6 +125,7 @@ $(objpfx)tst-bug18665: $(objpfx)libresolv.so $(shared-thread-library)
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$(objpfx)tst-res_use_inet6: $(objpfx)libresolv.so $(shared-thread-library)
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$(objpfx)tst-resolv-basic: $(objpfx)libresolv.so $(shared-thread-library)
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$(objpfx)tst-resolv-network: $(objpfx)libresolv.so $(shared-thread-library)
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$(objpfx)tst-resolv-qtypes: $(objpfx)libresolv.so $(shared-thread-library)
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$(objpfx)tst-resolv-search: $(objpfx)libresolv.so $(shared-thread-library)
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# This test case uses the deprecated RES_USE_INET6 resolver option.
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@ -324,7 +324,7 @@ _nss_dns_gethostbyname4_r (const char *name, struct gaih_addrtuple **pat,
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int olderr = errno;
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enum nss_status status;
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int n = __libc_res_nsearch (&_res, name, C_IN, T_UNSPEC,
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int n = __libc_res_nsearch (&_res, name, C_IN, T_QUERY_A_AND_AAAA,
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host_buffer.buf->buf, 2048, &host_buffer.ptr,
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&ans2p, &nans2p, &resplen2, &ans2p_malloced);
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if (n >= 0)
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@ -103,6 +103,10 @@ res_nmkquery(res_state statp,
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int n;
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u_char *dnptrs[20], **dpp, **lastdnptr;
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if (class < 0 || class > 65535
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|| type < 0 || type > 65535)
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return -1;
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#ifdef DEBUG
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if (statp->options & RES_DEBUG)
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printf(";; res_nmkquery(%s, %s, %s, %s)\n",
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@ -122,7 +122,7 @@ __libc_res_nquery(res_state statp,
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int n, use_malloc = 0;
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u_int oflags = statp->_flags;
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size_t bufsize = (type == T_UNSPEC ? 2 : 1) * QUERYSIZE;
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size_t bufsize = (type == T_QUERY_A_AND_AAAA ? 2 : 1) * QUERYSIZE;
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u_char *buf = alloca (bufsize);
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u_char *query1 = buf;
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int nquery1 = -1;
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@ -137,7 +137,7 @@ __libc_res_nquery(res_state statp,
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printf(";; res_query(%s, %d, %d)\n", name, class, type);
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#endif
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if (type == T_UNSPEC)
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if (type == T_QUERY_A_AND_AAAA)
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{
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n = res_nmkquery(statp, QUERY, name, class, T_A, NULL, 0, NULL,
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query1, bufsize);
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@ -190,7 +190,7 @@ __libc_res_nquery(res_state statp,
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if (__builtin_expect (n <= 0, 0) && !use_malloc) {
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/* Retry just in case res_nmkquery failed because of too
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short buffer. Shouldn't happen. */
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bufsize = (type == T_UNSPEC ? 2 : 1) * MAXPACKET;
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bufsize = (type == T_QUERY_A_AND_AAAA ? 2 : 1) * MAXPACKET;
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buf = malloc (bufsize);
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if (buf != NULL) {
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query1 = buf;
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@ -0,0 +1,185 @@
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/* Exercise low-level query functions with different QTYPEs.
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Copyright (C) 2016 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <resolv.h>
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#include <string.h>
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#include <support/check.h>
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#include <support/check_nss.h>
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#include <support/resolv_test.h>
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#include <support/support.h>
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#include <support/test-driver.h>
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#include <support/xmemstream.h>
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/* If ture, the response function will send the actual response packet
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over TCP instead of UDP. */
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static volatile bool force_tcp;
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/* Send back a fake resource record matching the QTYPE. */
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static void
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response (const struct resolv_response_context *ctx,
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struct resolv_response_builder *b,
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const char *qname, uint16_t qclass, uint16_t qtype)
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{
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if (force_tcp && ctx->tcp)
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{
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resolv_response_init (b, (struct resolv_response_flags) { .tc = 1 });
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resolv_response_add_question (b, qname, qclass, qtype);
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return;
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}
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resolv_response_init (b, (struct resolv_response_flags) { });
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resolv_response_add_question (b, qname, qclass, qtype);
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resolv_response_section (b, ns_s_an);
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resolv_response_open_record (b, qname, qclass, qtype, 0);
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resolv_response_add_data (b, &qtype, sizeof (qtype));
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resolv_response_close_record (b);
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}
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static const const char *domain = "www.example.com";
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static int
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wrap_res_query (int type, unsigned char *answer, int answer_length)
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{
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return res_query (domain, C_IN, type, answer, answer_length);
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}
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static int
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wrap_res_search (int type, unsigned char *answer, int answer_length)
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{
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return res_query (domain, C_IN, type, answer, answer_length);
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}
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static int
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wrap_res_querydomain (int type, unsigned char *answer, int answer_length)
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{
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return res_querydomain ("www", "example.com", C_IN, type,
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answer, answer_length);
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}
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static int
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wrap_res_send (int type, unsigned char *answer, int answer_length)
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{
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unsigned char buf[512];
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int ret = res_mkquery (QUERY, domain, C_IN, type,
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(const unsigned char *) "", 0, NULL,
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buf, sizeof (buf));
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if (type < 0 || type >= 65536)
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{
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/* res_mkquery fails for out-of-range record types. */
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TEST_VERIFY_EXIT (ret == -1);
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return -1;
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}
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TEST_VERIFY_EXIT (ret > 12); /* DNS header length. */
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return res_send (buf, ret, answer, answer_length);
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}
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static int
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wrap_res_nquery (int type, unsigned char *answer, int answer_length)
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{
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return res_nquery (&_res, domain, C_IN, type, answer, answer_length);
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}
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static int
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wrap_res_nsearch (int type, unsigned char *answer, int answer_length)
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{
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return res_nquery (&_res, domain, C_IN, type, answer, answer_length);
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}
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static int
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wrap_res_nquerydomain (int type, unsigned char *answer, int answer_length)
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{
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return res_nquerydomain (&_res, "www", "example.com", C_IN, type,
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answer, answer_length);
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}
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static int
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wrap_res_nsend (int type, unsigned char *answer, int answer_length)
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{
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unsigned char buf[512];
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int ret = res_nmkquery (&_res, QUERY, domain, C_IN, type,
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(const unsigned char *) "", 0, NULL,
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buf, sizeof (buf));
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if (type < 0 || type >= 65536)
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{
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/* res_mkquery fails for out-of-range record types. */
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TEST_VERIFY_EXIT (ret == -1);
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return -1;
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}
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TEST_VERIFY_EXIT (ret > 12); /* DNS header length. */
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return res_nsend (&_res, buf, ret, answer, answer_length);
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}
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static void
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test_function (const char *fname,
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int (*func) (int type,
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unsigned char *answer, int answer_length))
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{
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unsigned char buf[512];
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for (int tcp = 0; tcp < 2; ++tcp)
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{
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force_tcp = tcp;
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for (unsigned int type = 1; type <= 65535; ++type)
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{
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if (test_verbose)
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printf ("info: sending QTYPE %d with %s (tcp=%d)\n",
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type, fname, tcp);
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int ret = func (type, buf, sizeof (buf));
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if (ret != 47)
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FAIL_EXIT1 ("%s tcp=%d qtype=%d return value %d",
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fname,tcp, type, ret);
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/* One question, one answer record. */
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TEST_VERIFY (memcmp (buf + 4, "\0\1\0\1\0\0\0\0", 8) == 0);
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/* Question section. */
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static const char qname[] = "\3www\7example\3com";
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size_t qname_length = sizeof (qname);
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TEST_VERIFY (memcmp (buf + 12, qname, qname_length) == 0);
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/* RDATA part of answer. */
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uint16_t type16 = type;
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TEST_VERIFY (memcmp (buf + ret - 2, &type16, sizeof (type16)) == 0);
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}
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}
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TEST_VERIFY (func (-1, buf, sizeof (buf) == -1));
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TEST_VERIFY (func (65536, buf, sizeof (buf) == -1));
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}
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static int
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do_test (void)
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{
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struct resolv_redirect_config config =
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{
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.response_callback = response,
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};
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struct resolv_test *obj = resolv_test_start (config);
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test_function ("res_query", &wrap_res_query);
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test_function ("res_search", &wrap_res_search);
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test_function ("res_querydomain", &wrap_res_querydomain);
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test_function ("res_send", &wrap_res_send);
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test_function ("res_nquery", &wrap_res_nquery);
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test_function ("res_nsearch", &wrap_res_nsearch);
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test_function ("res_nquerydomain", &wrap_res_nquerydomain);
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test_function ("res_nsend", &wrap_res_nsend);
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resolv_test_end (obj);
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return 0;
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}
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#define TIMEOUT 300
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#include <support/test-driver.c>
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