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* [glibc] resolv: Add tst-resolv-byaddr for testing reverse lookup
@ 2022-08-30 8:03 Florian Weimer
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From: Florian Weimer @ 2022-08-30 8:03 UTC (permalink / raw)
To: glibc-cvs
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=0b99828d54e5d1fc8f5ad3edf5ba262ad2e9c5b0
commit 0b99828d54e5d1fc8f5ad3edf5ba262ad2e9c5b0
Author: Florian Weimer <fweimer@redhat.com>
Date: Tue Aug 30 10:02:49 2022 +0200
resolv: Add tst-resolv-byaddr for testing reverse lookup
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Diff:
---
resolv/Makefile | 2 +
resolv/tst-resolv-byaddr.c | 326 +++++++++++++++++++++++++++++++++++
resolv/tst-resolv-maybe_insert_sig.h | 32 ++++
3 files changed, 360 insertions(+)
diff --git a/resolv/Makefile b/resolv/Makefile
index 5b15321f9b..98b10d97a0 100644
--- a/resolv/Makefile
+++ b/resolv/Makefile
@@ -91,6 +91,7 @@ tests += \
tst-res_hnok \
tst-resolv-basic \
tst-resolv-binary \
+ tst-resolv-byaddr \
tst-resolv-edns \
tst-resolv-network \
tst-resolv-noaaaa \
@@ -260,6 +261,7 @@ $(objpfx)tst-resolv-ai_idn-nolibidn2.out: \
$(gen-locales) $(objpfx)tst-no-libidn2.so
$(objpfx)tst-resolv-basic: $(objpfx)libresolv.so $(shared-thread-library)
$(objpfx)tst-resolv-binary: $(objpfx)libresolv.so $(shared-thread-library)
+$(objpfx)tst-resolv-byaddr: $(objpfx)libresolv.so $(shared-thread-library)
$(objpfx)tst-resolv-edns: $(objpfx)libresolv.so $(shared-thread-library)
$(objpfx)tst-resolv-network: $(objpfx)libresolv.so $(shared-thread-library)
$(objpfx)tst-resolv-res_init: $(objpfx)libresolv.so
diff --git a/resolv/tst-resolv-byaddr.c b/resolv/tst-resolv-byaddr.c
new file mode 100644
index 0000000000..6299e89837
--- /dev/null
+++ b/resolv/tst-resolv-byaddr.c
@@ -0,0 +1,326 @@
+/* Test reverse DNS lookup.
+ Copyright (C) 2022 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ 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
+ <https://www.gnu.org/licenses/>. */
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <netdb.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <support/check.h>
+#include <support/check_nss.h>
+#include <support/next_to_fault.h>
+#include <support/resolv_test.h>
+#include <support/support.h>
+
+#include "tst-resolv-maybe_insert_sig.h"
+
+/* QNAME format:
+
+ ADDRESSES.CNAMES...(lots of 0s)...8.b.d.0.1.0.0.2.ip6.arpa.
+ CNAMES|ADDRESSES.2.0.192.in-addr-arpa.
+
+ For the IPv4 reverse lookup, the address count is in the lower
+ bits.
+
+ CNAMES is the length of the CNAME chain, ADDRESSES is the number of
+ addresses in the response. The special value 15 means that there
+ are no addresses, and the RCODE is NXDOMAIN. */
+static void
+response (const struct resolv_response_context *ctx,
+ struct resolv_response_builder *b,
+ const char *qname, uint16_t qclass, uint16_t qtype)
+{
+ TEST_COMPARE (qclass, C_IN);
+ TEST_COMPARE (qtype, T_PTR);
+
+ unsigned int addresses, cnames, bits;
+ char *tail;
+ if (strstr (qname, "ip6.arpa") != NULL
+ && sscanf (qname, "%x.%x.%ms", &addresses, &cnames, &tail) == 3)
+ TEST_COMPARE_STRING (tail, "\
+0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa");
+ else if (sscanf (qname, "%u.%ms", &bits, &tail) == 2)
+ {
+ TEST_COMPARE_STRING (tail, "2.0.192.in-addr.arpa");
+ addresses = bits & 0x0f;
+ cnames = bits >> 4;
+ }
+ else
+ FAIL_EXIT1 ("invalid QNAME: %s", qname);
+ free (tail);
+
+ int rcode;
+ if (addresses == 15)
+ {
+ /* Special case: Use no addresses with NXDOMAIN response. */
+ rcode = ns_r_nxdomain;
+ addresses = 0;
+ }
+ else
+ rcode = 0;
+
+ struct resolv_response_flags flags = { .rcode = rcode };
+ resolv_response_init (b, flags);
+ resolv_response_add_question (b, qname, qclass, qtype);
+ resolv_response_section (b, ns_s_an);
+ maybe_insert_sig (b, qname);
+
+ /* Provide the requested number of CNAME records. */
+ char *previous_name = (char *) qname;
+ for (int unique = 0; unique < cnames; ++unique)
+ {
+ resolv_response_open_record (b, previous_name, qclass, T_CNAME, 60);
+ char *new_name = xasprintf ("%d.alias.example", unique);
+ resolv_response_add_name (b, new_name);
+ resolv_response_close_record (b);
+
+ maybe_insert_sig (b, qname);
+
+ if (previous_name != qname)
+ free (previous_name);
+ previous_name = new_name;
+ }
+
+ for (int unique = 0; unique < addresses; ++unique)
+ {
+ resolv_response_open_record (b, previous_name, qclass, T_PTR, 60);
+ char *ptr = xasprintf ("unique-%d.cnames-%u.addresses-%u.example",
+ unique, cnames, addresses);
+ resolv_response_add_name (b, ptr);
+ free (ptr);
+ resolv_response_close_record (b);
+ }
+
+ if (previous_name != qname)
+ free (previous_name);
+}
+
+/* Used to check that gethostbyaddr_r does not write past the buffer
+ end. */
+static struct support_next_to_fault ntf;
+
+/* Perform a gethostbyaddr call and check the result. */
+static void
+check_gethostbyaddr (const char *address, const char *expected)
+{
+ unsigned char bytes[16];
+ unsigned int byteslen;
+ int family;
+ if (strchr (address, ':') != NULL)
+ {
+ family = AF_INET6;
+ byteslen = 16;
+ }
+ else
+ {
+ family = AF_INET;
+ byteslen = 4;
+ }
+ TEST_COMPARE (inet_pton (family, address, bytes), 1);
+
+ struct hostent *e = gethostbyaddr (bytes, byteslen, family);
+ check_hostent (address, e, expected);
+
+ if (e == NULL)
+ return;
+
+ /* Try gethostbyaddr_r with increasing sizes until success. First
+ compute a reasonable minimum buffer size, to avoid many pointless
+ attempts. */
+ size_t minimum_size = strlen (e->h_name);
+ for (int i = 0; e->h_addr_list[i] != NULL; ++i)
+ minimum_size += e->h_length + sizeof (char *);
+ for (int i = 0; e->h_aliases[i] != NULL; ++i)
+ minimum_size += strlen (e->h_aliases[i]) + 1 + sizeof (char *);
+
+ /* Gradually increase the size until success. */
+ for (size_t size = minimum_size; size < ntf.length; ++size)
+ {
+ struct hostent result;
+ int herrno;
+ int ret = gethostbyaddr_r (bytes, byteslen, family, &result,
+ ntf.buffer + ntf.length - size, size,
+ &e, &herrno);
+ if (ret == ERANGE)
+ /* Retry with larger size. */
+ TEST_COMPARE (herrno, NETDB_INTERNAL);
+ else if (ret == 0)
+ {
+ TEST_VERIFY (size > minimum_size);
+ check_hostent (address, e, expected);
+ return;
+ }
+ else
+ FAIL_EXIT1 ("Unexpected gethostbyaddr_r failure: %d", ret);
+ }
+
+ FAIL_EXIT1 ("gethostbyaddr_r always failed for: %s", address);
+}
+
+/* Perform a getnameinfo call and check the result. */
+static void
+check_getnameinfo (const char *address, const char *expected)
+{
+ struct sockaddr_in sin = { };
+ struct sockaddr_in6 sin6 = { };
+ void *sa;
+ socklen_t salen;
+ if (strchr (address, ':') != NULL)
+ {
+ sin6.sin6_family = AF_INET6;
+ TEST_COMPARE (inet_pton (AF_INET6, address, &sin6.sin6_addr), 1);
+ sin6.sin6_port = htons (80);
+ sa = &sin6;
+ salen = sizeof (sin6);
+ }
+ else
+ {
+ sin.sin_family = AF_INET;
+ TEST_COMPARE (inet_pton (AF_INET, address, &sin.sin_addr), 1);
+ sin.sin_port = htons (80);
+ sa = &sin;
+ salen = sizeof (sin);
+ }
+
+ char host[64];
+ char service[64];
+ int ret = getnameinfo (sa, salen, host,
+ sizeof (host), service, sizeof (service),
+ NI_NAMEREQD | NI_NUMERICSERV);
+ switch (ret)
+ {
+ case 0:
+ TEST_COMPARE_STRING (host, expected);
+ TEST_COMPARE_STRING (service, "80");
+ break;
+ case EAI_SYSTEM:
+ TEST_COMPARE_STRING (strerror (errno), expected);
+ break;
+ default:
+ TEST_COMPARE_STRING (gai_strerror (ret), expected);
+ }
+}
+
+static int
+do_test (void)
+{
+ /* Some reasonably upper bound for the maximum response size. */
+ ntf = support_next_to_fault_allocate (4096);
+
+ struct resolv_test *obj = resolv_test_start
+ ((struct resolv_redirect_config)
+ {
+ .response_callback = response
+ });
+
+ for (int do_insert_sig = 0; do_insert_sig < 2; ++do_insert_sig)
+ {
+ insert_sig = do_insert_sig;
+
+ /* No PTR record, RCODE=0. */
+ check_gethostbyaddr ("192.0.2.0", "error: NO_RECOVERY\n");
+ check_getnameinfo ("192.0.2.0", "Name or service not known");
+ check_gethostbyaddr ("192.0.2.16", "error: NO_RECOVERY\n");
+ check_getnameinfo ("192.0.2.16", "Name or service not known");
+ check_gethostbyaddr ("192.0.2.32", "error: NO_RECOVERY\n");
+ check_getnameinfo ("192.0.2.32", "Name or service not known");
+ check_gethostbyaddr ("2001:db8::", "error: NO_RECOVERY\n");
+ check_getnameinfo ("2001:db8::", "Name or service not known");
+ check_gethostbyaddr ("2001:db8::10", "error: NO_RECOVERY\n");
+ check_getnameinfo ("2001:db8::10", "Name or service not known");
+ check_gethostbyaddr ("2001:db8::20", "error: NO_RECOVERY\n");
+ check_getnameinfo ("2001:db8::20", "Name or service not known");
+
+ /* No PTR record, NXDOMAIN. */
+ check_gethostbyaddr ("192.0.2.15", "error: HOST_NOT_FOUND\n");
+ check_getnameinfo ("192.0.2.15", "Name or service not known");
+ check_gethostbyaddr ("192.0.2.31", "error: HOST_NOT_FOUND\n");
+ check_getnameinfo ("192.0.2.31", "Name or service not known");
+ check_gethostbyaddr ("192.0.2.47", "error: HOST_NOT_FOUND\n");
+ check_getnameinfo ("192.0.2.47", "Name or service not known");
+ check_gethostbyaddr ("2001:db8::f", "error: HOST_NOT_FOUND\n");
+ check_getnameinfo ("2001:db8::f", "Name or service not known");
+ check_gethostbyaddr ("2001:db8::1f", "error: HOST_NOT_FOUND\n");
+ check_getnameinfo ("2001:db8::1f", "Name or service not known");
+ check_gethostbyaddr ("2001:db8::2f", "error: HOST_NOT_FOUND\n");
+ check_getnameinfo ("2001:db8::2f", "Name or service not known");
+
+ /* Actual response data. Only the first PTR record is returned. */
+ check_gethostbyaddr ("192.0.2.1",
+ "name: unique-0.cnames-0.addresses-1.example\n"
+ "address: 192.0.2.1\n");
+ check_getnameinfo ("192.0.2.1",
+ "unique-0.cnames-0.addresses-1.example");
+ check_gethostbyaddr ("192.0.2.17",
+ "name: unique-0.cnames-1.addresses-1.example\n"
+ "address: 192.0.2.17\n");
+ check_getnameinfo ("192.0.2.17",
+ "unique-0.cnames-1.addresses-1.example");
+ check_gethostbyaddr ("192.0.2.18",
+ "name: unique-0.cnames-1.addresses-2.example\n"
+ "address: 192.0.2.18\n");
+ check_getnameinfo ("192.0.2.18",
+ "unique-0.cnames-1.addresses-2.example");
+ check_gethostbyaddr ("192.0.2.33",
+ "name: unique-0.cnames-2.addresses-1.example\n"
+ "address: 192.0.2.33\n");
+ check_getnameinfo ("192.0.2.33",
+ "unique-0.cnames-2.addresses-1.example");
+ check_gethostbyaddr ("192.0.2.34",
+ "name: unique-0.cnames-2.addresses-2.example\n"
+ "address: 192.0.2.34\n");
+ check_getnameinfo ("192.0.2.34",
+ "unique-0.cnames-2.addresses-2.example");
+
+ /* Same for IPv6 addresses. */
+ check_gethostbyaddr ("2001:db8::1",
+ "name: unique-0.cnames-0.addresses-1.example\n"
+ "address: 2001:db8::1\n");
+ check_getnameinfo ("2001:db8::1",
+ "unique-0.cnames-0.addresses-1.example");
+ check_gethostbyaddr ("2001:db8::11",
+ "name: unique-0.cnames-1.addresses-1.example\n"
+ "address: 2001:db8::11\n");
+ check_getnameinfo ("2001:db8::11",
+ "unique-0.cnames-1.addresses-1.example");
+ check_gethostbyaddr ("2001:db8::12",
+ "name: unique-0.cnames-1.addresses-2.example\n"
+ "address: 2001:db8::12\n");
+ check_getnameinfo ("2001:db8::12",
+ "unique-0.cnames-1.addresses-2.example");
+ check_gethostbyaddr ("2001:db8::21",
+ "name: unique-0.cnames-2.addresses-1.example\n"
+ "address: 2001:db8::21\n");
+ check_getnameinfo ("2001:db8::21",
+ "unique-0.cnames-2.addresses-1.example");
+ check_gethostbyaddr ("2001:db8::22",
+ "name: unique-0.cnames-2.addresses-2.example\n"
+ "address: 2001:db8::22\n");
+ check_getnameinfo ("2001:db8::22",
+ "unique-0.cnames-2.addresses-2.example");
+ }
+
+ resolv_test_end (obj);
+
+ support_next_to_fault_free (&ntf);
+ return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/resolv/tst-resolv-maybe_insert_sig.h b/resolv/tst-resolv-maybe_insert_sig.h
new file mode 100644
index 0000000000..05725225af
--- /dev/null
+++ b/resolv/tst-resolv-maybe_insert_sig.h
@@ -0,0 +1,32 @@
+/* Code snippet for optionally inserting ignored SIG records in resolver tests.
+ Copyright (C) 2022 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ 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
+ <https://www.gnu.org/licenses/>. */
+
+/* Set to true for an alternative pass that inserts (ignored) SIG
+ records. This does not alter the response, so this property is not
+ encoded in the QNAME. The variable needs to be volatile because
+ leaf attributes tell GCC that the response function is not
+ called. */
+static volatile bool insert_sig;
+
+static void
+maybe_insert_sig (struct resolv_response_builder *b, const char *owner)
+{
+ resolv_response_open_record (b, owner, C_IN, T_SIG, 60);
+ resolv_response_add_data (b, "", 1);
+ resolv_response_close_record (b);
+}
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