resolv: Implement no-aaaa stub resolver option

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

1 files changed, 533 insertions, 0 deletions

diff --git a/resolv/tst-resolv-noaaaa.c b/resolv/tst-resolv-noaaaa.c
new file mode 100644
index 0000000000..56b25f88a5
--- /dev/null
+++ b/resolv/tst-resolv-noaaaa.c
@@ -0,0 +1,533 @@
+/* Test the RES_NOAAAA resolver option.
+   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 <errno.h>
+#include <netdb.h>
+#include <resolv.h>
+#include <stdlib.h>
+#include <support/check.h>
+#include <support/check_nss.h>
+#include <support/resolv_test.h>
+#include <support/support.h>
+
+/* Used to keep track of the number of queries.  */
+static volatile unsigned int queries;
+
+static void
+response (const struct resolv_response_context *ctx,
+          struct resolv_response_builder *b,
+          const char *qname, uint16_t qclass, uint16_t qtype)
+{
+  /* Each test should only send one query.  */
+  ++queries;
+  TEST_COMPARE (queries, 1);
+
+  /* AAAA queries are supposed to be disabled.  */
+  TEST_VERIFY (qtype != T_AAAA);
+  TEST_COMPARE (qclass, C_IN);
+
+  /* The only other query type besides A is PTR.  */
+  if (qtype != T_A)
+    TEST_COMPARE (qtype, T_PTR);
+
+  int an, ns, ar;
+  char *tail;
+  if (sscanf (qname, "an%d.ns%d.ar%d.%ms", &an, &ns, &ar, &tail) != 4)
+    FAIL_EXIT1 ("invalid QNAME: %s\n", qname);
+  TEST_COMPARE_STRING (tail, "example");
+  free (tail);
+
+  if (an < 0 || ns < 0 || ar < 0)
+    {
+      struct resolv_response_flags flags = { .rcode = NXDOMAIN, };
+      resolv_response_init (b, flags);
+      resolv_response_add_question (b, qname, qclass, qtype);
+      return;
+    }
+
+  struct resolv_response_flags flags = {};
+  resolv_response_init (b, flags);
+  resolv_response_add_question (b, qname, qclass, qtype);
+
+  resolv_response_section (b, ns_s_an);
+  for (int i = 0; i < an; ++i)
+    {
+      resolv_response_open_record (b, qname, qclass, qtype, 60);
+      switch (qtype)
+        {
+        case T_A:
+          char ipv4[4] = {192, 0, 2, i + 1};
+          resolv_response_add_data (b, &ipv4, sizeof (ipv4));
+          break;
+
+        case T_PTR:
+          char *name = xasprintf ("ptr-%d", i);
+          resolv_response_add_name (b, name);
+          free (name);
+          break;
+        }
+      resolv_response_close_record (b);
+    }
+
+  resolv_response_section (b, ns_s_ns);
+  for (int i = 0; i < ns; ++i)
+    {
+      resolv_response_open_record (b, qname, qclass, T_NS, 60);
+      char *name = xasprintf ("ns%d.example.net", i);
+      resolv_response_add_name (b, name);
+      free (name);
+      resolv_response_close_record (b);
+    }
+
+  resolv_response_section (b, ns_s_ar);
+  int addr = 1;
+  for (int i = 0; i < ns; ++i)
+    {
+      char *name = xasprintf ("ns%d.example.net", i);
+      for (int j = 0; j < ar; ++j)
+        {
+          resolv_response_open_record (b, name, qclass, T_A, 60);
+          char ipv4[4] = {192, 0, 2, addr};
+          resolv_response_add_data (b, &ipv4, sizeof (ipv4));
+          resolv_response_close_record (b);
+
+          resolv_response_open_record (b, name, qclass, T_AAAA, 60);
+          char ipv6[16]
+            = {0x20, 0x01, 0xd, 0xb8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, addr};
+          resolv_response_add_data (b, &ipv6, sizeof (ipv6));
+          resolv_response_close_record (b);
+
+          ++addr;
+        }
+      free (name);
+    }
+}
+
+/* Number of modes.  Lowest bit encodes *n* function vs implicit _res
+   argument.  The mode numbers themselves are arbitrary.  */
+enum { mode_count = 8 };
+
+/* res_send-like modes do not perform error translation.  */
+enum { first_send_mode = 6 };
+
+static int
+libresolv_query (unsigned int mode, const char *qname, uint16_t qtype,
+                 unsigned char *buf, size_t buflen)
+{
+  int saved_errno = errno;
+
+  TEST_VERIFY_EXIT (mode < mode_count);
+
+  switch (mode)
+    {
+    case 0:
+      return res_query (qname, C_IN, qtype, buf, buflen);
+    case 1:
+      return res_nquery (&_res, qname, C_IN, qtype, buf, buflen);
+    case 2:
+      return res_search (qname, C_IN, qtype, buf, buflen);
+    case 3:
+      return res_nsearch (&_res, qname, C_IN, qtype, buf, buflen);
+    case 4:
+      return res_querydomain (qname, "", C_IN, qtype, buf, buflen);
+    case 5:
+      return res_nquerydomain (&_res, qname, "", C_IN, qtype, buf, buflen);
+    case 6:
+      {
+        unsigned char querybuf[512];
+        int ret = res_mkquery (QUERY, qname, C_IN, qtype,
+                               NULL, 0, NULL, querybuf, sizeof (querybuf));
+        TEST_VERIFY_EXIT (ret > 0);
+        errno = saved_errno;
+        return res_send (querybuf, ret, buf, buflen);
+      }
+    case 7:
+      {
+        unsigned char querybuf[512];
+        int ret = res_nmkquery (&_res, QUERY, qname, C_IN, qtype,
+                                NULL, 0, NULL, querybuf, sizeof (querybuf));
+        TEST_VERIFY_EXIT (ret > 0);
+        errno = saved_errno;
+        return res_nsend (&_res, querybuf, ret, buf, buflen);
+      }
+    }
+  __builtin_unreachable ();
+}
+
+static int
+do_test (void)
+{
+  struct resolv_test *obj = resolv_test_start
+    ((struct resolv_redirect_config)
+     {
+       .response_callback = response
+     });
+
+  _res.options |= RES_NOAAAA;
+
+  check_hostent ("an1.ns2.ar1.example",
+                 gethostbyname ("an1.ns2.ar1.example"),
+                 "name: an1.ns2.ar1.example\n"
+                 "address: 192.0.2.1\n");
+  queries = 0;
+  check_hostent ("an0.ns2.ar1.example",
+                 gethostbyname ("an0.ns2.ar1.example"),
+                 "error: NO_ADDRESS\n");
+  queries = 0;
+  check_hostent ("an-1.ns2.ar1.example",
+                 gethostbyname ("an-1.ns2.ar1.example"),
+                 "error: HOST_NOT_FOUND\n");
+  queries = 0;
+
+  check_hostent ("an1.ns2.ar1.example AF_INET",
+                 gethostbyname2 ("an1.ns2.ar1.example", AF_INET),
+                 "name: an1.ns2.ar1.example\n"
+                 "address: 192.0.2.1\n");
+  queries = 0;
+  check_hostent ("an0.ns2.ar1.example AF_INET",
+                 gethostbyname2 ("an0.ns2.ar1.example", AF_INET),
+                 "error: NO_ADDRESS\n");
+  queries = 0;
+  check_hostent ("an-1.ns2.ar1.example AF_INET",
+                 gethostbyname2 ("an-1.ns2.ar1.example", AF_INET),
+                 "error: HOST_NOT_FOUND\n");
+  queries = 0;
+
+  check_hostent ("an1.ns2.ar1.example AF_INET6",
+                 gethostbyname2 ("an1.ns2.ar1.example", AF_INET6),
+                 "error: NO_ADDRESS\n");
+  queries = 0;
+  check_hostent ("an0.ns2.ar1.example AF_INET6",
+                 gethostbyname2 ("an0.ns2.ar1.example", AF_INET6),
+                 "error: NO_ADDRESS\n");
+  queries = 0;
+  check_hostent ("an-1.ns2.ar1.example AF_INET6",
+                 gethostbyname2 ("an-1.ns2.ar1.example", AF_INET6),
+                 "error: HOST_NOT_FOUND\n");
+  queries = 0;
+
+  /* Multiple addresses.  */
+  check_hostent ("an2.ns0.ar0.example",
+                 gethostbyname ("an2.ns0.ar0.example"),
+                 "name: an2.ns0.ar0.example\n"
+                 "address: 192.0.2.1\n"
+                 "address: 192.0.2.2\n");
+  queries = 0;
+  check_hostent ("an2.ns0.ar0.example AF_INET6",
+                 gethostbyname2 ("an2.ns0.ar0.example", AF_INET6),
+                 "error: NO_ADDRESS\n");
+  queries = 0;
+
+  /* getaddrinfo checks with one address.  */
+  struct addrinfo *ai;
+  int ret;
+  ret = getaddrinfo ("an1.ns2.ar1.example", "80",
+                     &(struct addrinfo)
+                     {
+                       .ai_family = AF_INET,
+                       .ai_socktype = SOCK_STREAM,
+                     }, &ai);
+  check_addrinfo ("an1.ns2.ar1.example (AF_INET)", ai, ret,
+                  "address: STREAM/TCP 192.0.2.1 80\n");
+  freeaddrinfo (ai);
+  queries = 0;
+  ret = getaddrinfo ("an1.ns2.ar1.example", "80",
+                     &(struct addrinfo)
+                     {
+                       .ai_family = AF_INET6,
+                       .ai_socktype = SOCK_STREAM,
+                     }, &ai);
+  check_addrinfo ("an1.ns2.ar1.example (AF_INET6)", ai, ret,
+                  "error: No address associated with hostname\n");
+  queries = 0;
+  ret = getaddrinfo ("an1.ns2.ar1.example", "80",
+                     &(struct addrinfo)
+                     {
+                       .ai_family = AF_UNSPEC,
+                       .ai_socktype = SOCK_STREAM,
+                     }, &ai);
+  check_addrinfo ("an1.ns2.ar1.example (AF_UNSPEC)", ai, ret,
+                  "address: STREAM/TCP 192.0.2.1 80\n");
+  freeaddrinfo (ai);
+  queries = 0;
+
+  /* getaddrinfo checks with three addresses.  */
+  ret = getaddrinfo ("an3.ns2.ar1.example", "80",
+                     &(struct addrinfo)
+                     {
+                       .ai_family = AF_INET,
+                       .ai_socktype = SOCK_STREAM,
+                     }, &ai);
+  check_addrinfo ("an3.ns2.ar1.example (AF_INET)", ai, ret,
+                  "address: STREAM/TCP 192.0.2.1 80\n"
+                  "address: STREAM/TCP 192.0.2.2 80\n"
+                  "address: STREAM/TCP 192.0.2.3 80\n");
+  freeaddrinfo (ai);
+  queries = 0;
+  ret = getaddrinfo ("an3.ns2.ar1.example", "80",
+                     &(struct addrinfo)
+                     {
+                       .ai_family = AF_INET6,
+                       .ai_socktype = SOCK_STREAM,
+                     }, &ai);
+  check_addrinfo ("an3.ns2.ar1.example (AF_INET6)", ai, ret,
+                  "error: No address associated with hostname\n");
+  queries = 0;
+  ret = getaddrinfo ("an3.ns2.ar1.example", "80",
+                     &(struct addrinfo)
+                     {
+                       .ai_family = AF_UNSPEC,
+                       .ai_socktype = SOCK_STREAM,
+                     }, &ai);
+  check_addrinfo ("an3.ns2.ar1.example (AF_UNSPEC)", ai, ret,
+                  "address: STREAM/TCP 192.0.2.1 80\n"
+                  "address: STREAM/TCP 192.0.2.2 80\n"
+                  "address: STREAM/TCP 192.0.2.3 80\n");
+  freeaddrinfo (ai);
+  queries = 0;
+
+  /* getaddrinfo checks with no address.  */
+  ret = getaddrinfo ("an0.ns2.ar1.example", "80",
+                     &(struct addrinfo)
+                     {
+                       .ai_family = AF_INET,
+                       .ai_socktype = SOCK_STREAM,
+                     }, &ai);
+  check_addrinfo ("an0.ns2.ar1.example (AF_INET)", ai, ret,
+                  "error: No address associated with hostname\n");
+  queries = 0;
+  ret = getaddrinfo ("an0.ns2.ar1.example", "80",
+                     &(struct addrinfo)
+                     {
+                       .ai_family = AF_INET6,
+                       .ai_socktype = SOCK_STREAM,
+                     }, &ai);
+  check_addrinfo ("an0.ns2.ar1.example (AF_INET6)", ai, ret,
+                  "error: No address associated with hostname\n");
+  queries = 0;
+  ret = getaddrinfo ("an0.ns2.ar1.example", "80",
+                     &(struct addrinfo)
+                     {
+                       .ai_family = AF_UNSPEC,
+                       .ai_socktype = SOCK_STREAM,
+                     }, &ai);
+  check_addrinfo ("an-1.ns2.ar1.example (AF_UNSPEC)", ai, ret,
+                  "error: No address associated with hostname\n");
+  queries = 0;
+
+  /* getaddrinfo checks with NXDOMAIN.  */
+  ret = getaddrinfo ("an-1.ns2.ar1.example", "80",
+                     &(struct addrinfo)
+                     {
+                       .ai_family = AF_INET,
+                       .ai_socktype = SOCK_STREAM,
+                     }, &ai);
+  check_addrinfo ("an-1.ns2.ar1.example (AF_INET)", ai, ret,
+                  "error: Name or service not known\n");
+  queries = 0;
+  ret = getaddrinfo ("an-1.ns2.ar1.example", "80",
+                     &(struct addrinfo)
+                     {
+                       .ai_family = AF_INET6,
+                       .ai_socktype = SOCK_STREAM,
+                     }, &ai);
+  check_addrinfo ("an-1.ns2.ar1.example (AF_INET6)", ai, ret,
+                  "error: Name or service not known\n");
+  queries = 0;
+  ret = getaddrinfo ("an-1.ns2.ar1.example", "80",
+                     &(struct addrinfo)
+                     {
+                       .ai_family = AF_UNSPEC,
+                       .ai_socktype = SOCK_STREAM,
+                     }, &ai);
+  check_addrinfo ("an-1.ns2.ar1.example (AF_UNSPEC)", ai, ret,
+                  "error: Name or service not known\n");
+  queries = 0;
+
+  for (unsigned int mode = 0; mode < mode_count; ++mode)
+    {
+      unsigned char *buf;
+      int ret;
+
+      /* Response for A.  */
+      buf = malloc (512);
+      ret = libresolv_query (mode, "an1.ns2.ar1.example", T_A, buf, 512);
+      TEST_VERIFY_EXIT (ret > 0);
+      check_dns_packet ("an1.ns2.ar1.example A", buf, ret,
+                        "name: an1.ns2.ar1.example\n"
+                        "address: 192.0.2.1\n");
+      free (buf);
+      queries = 0;
+
+      /* NODATA response for A.  */
+      buf = malloc (512);
+      errno = 0;
+      ret = libresolv_query (mode, "an0.ns2.ar1.example", T_A, buf, 512);
+      if (mode < first_send_mode)
+        {
+          TEST_COMPARE (ret, -1);
+          TEST_COMPARE (errno, 0);
+          TEST_COMPARE (h_errno, NO_ADDRESS);
+        }
+      else
+        {
+          TEST_VERIFY_EXIT (ret > 0);
+          TEST_COMPARE (((HEADER *)buf)->rcode, 0);
+          check_dns_packet ("an1.ns2.ar1.example A", buf, ret,
+                            "name: an0.ns2.ar1.example\n");
+        }
+      free (buf);
+      queries = 0;
+
+      /* NXDOMAIN response for A.  */
+      buf = malloc (512);
+      errno = 0;
+      ret = libresolv_query (mode, "an-1.ns2.ar1.example", T_A, buf, 512);
+      if (mode < first_send_mode)
+        {
+          TEST_COMPARE (ret, -1);
+          TEST_COMPARE (errno, 0);
+          TEST_COMPARE (h_errno, HOST_NOT_FOUND);
+        }
+      else
+        {
+          TEST_VERIFY_EXIT (ret > 0);
+          TEST_COMPARE (((HEADER *)buf)->rcode, NXDOMAIN);
+          check_dns_packet ("an1.ns2.ar1.example A", buf, ret,
+                            "name: an-1.ns2.ar1.example\n");
+        }
+      free (buf);
+      queries = 0;
+
+      /* Response for PTR.  */
+      buf = malloc (512);
+      ret = libresolv_query (mode, "an1.ns2.ar1.example", T_PTR, buf, 512);
+      TEST_VERIFY_EXIT (ret > 0);
+      check_dns_packet ("an1.ns2.ar1.example PTR", buf, ret,
+                        "name: an1.ns2.ar1.example\n"
+                        "data: an1.ns2.ar1.example PTR ptr-0\n");
+      free (buf);
+      queries = 0;
+
+      /* NODATA response for PTR.  */
+      buf = malloc (512);
+      errno = 0;
+      ret = libresolv_query (mode, "an0.ns2.ar1.example", T_PTR, buf, 512);
+      if (mode < first_send_mode)
+        {
+          TEST_COMPARE (ret, -1);
+          TEST_COMPARE (errno, 0);
+          TEST_COMPARE (h_errno, NO_ADDRESS);
+        }
+      else
+        {
+          TEST_VERIFY_EXIT (ret > 0);
+          TEST_COMPARE (((HEADER *)buf)->rcode, 0);
+          check_dns_packet ("an1.ns2.ar1.example PTR", buf, ret,
+                            "name: an0.ns2.ar1.example\n");
+        }
+      free (buf);
+      queries = 0;
+
+      /* NXDOMAIN response for PTR.  */
+      buf = malloc (512);
+      errno = 0;
+      ret = libresolv_query (mode, "an-1.ns2.ar1.example", T_PTR, buf, 512);
+      if (mode < first_send_mode)
+        {
+          TEST_COMPARE (ret, -1);
+          TEST_COMPARE (errno, 0);
+          TEST_COMPARE (h_errno, HOST_NOT_FOUND);
+        }
+      else
+        {
+          TEST_VERIFY_EXIT (ret > 0);
+          TEST_COMPARE (((HEADER *)buf)->rcode, NXDOMAIN);
+          check_dns_packet ("an1.ns2.ar1.example PTR", buf, ret,
+                            "name: an-1.ns2.ar1.example\n");
+        }
+      free (buf);
+      queries = 0;
+
+      /* NODATA response for AAAA.  */
+      buf = malloc (512);
+      errno = 0;
+      ret = libresolv_query (mode, "an1.ns2.ar1.example", T_AAAA, buf, 512);
+      if (mode < first_send_mode)
+        {
+          TEST_COMPARE (ret, -1);
+          TEST_COMPARE (errno, 0);
+          TEST_COMPARE (h_errno, NO_ADDRESS);
+        }
+      else
+        {
+          TEST_VERIFY_EXIT (ret > 0);
+          TEST_COMPARE (((HEADER *)buf)->rcode, 0);
+          check_dns_packet ("an1.ns2.ar1.example A", buf, ret,
+                            "name: an1.ns2.ar1.example\n");
+        }
+      free (buf);
+      queries = 0;
+
+      /* NODATA response for AAAA (original is already NODATA).  */
+      buf = malloc (512);
+      errno = 0;
+      ret = libresolv_query (mode, "an0.ns2.ar1.example", T_AAAA, buf, 512);
+      if (mode < first_send_mode)
+        {
+          TEST_COMPARE (ret, -1);
+          TEST_COMPARE (errno, 0);
+          TEST_COMPARE (h_errno, NO_ADDRESS);
+        }
+      else
+        {
+          TEST_VERIFY_EXIT (ret > 0);
+          TEST_COMPARE (((HEADER *)buf)->rcode, 0);
+          check_dns_packet ("an0.ns2.ar1.example A", buf, ret,
+                            "name: an0.ns2.ar1.example\n");
+        }
+      free (buf);
+      queries = 0;
+
+      /* NXDOMAIN response.  */
+      buf = malloc (512);
+      errno = 0;
+      ret = libresolv_query (mode, "an-1.ns2.ar1.example", T_AAAA, buf, 512);
+      if (mode < first_send_mode)
+        {
+          TEST_COMPARE (ret, -1);
+          TEST_COMPARE (errno, 0);
+          TEST_COMPARE (h_errno, HOST_NOT_FOUND);
+        }
+      else
+        {
+          TEST_VERIFY_EXIT (ret > 0);
+          TEST_COMPARE (((HEADER *)buf)->rcode, NXDOMAIN);
+          check_dns_packet ("an-1.ns2.ar1.example A", buf, ret,
+                            "name: an-1.ns2.ar1.example\n");
+        }
+      free (buf);
+      queries = 0;
+    }
+
+  resolv_test_end (obj);
+
+  return 0;
+}
+
+#include <support/test-driver.c>