CVE-2016-10739: getaddrinfo: Fully parse IPv4 address strings [BZ #20018]

The IPv4 address parser in the getaddrinfo function is changed so that
it does not ignore trailing whitespace and all characters after it.
For backwards compatibility, the getaddrinfo function still recognizes
legacy name syntax, such as 192.000.002.010 interpreted as 192.0.2.8
(octal).

This commit does not change the behavior of inet_addr and inet_aton.
gethostbyname already had additional sanity checks (but is switched
over to the new __inet_aton_exact function for completeness as well).

To avoid sending the problematic query names over DNS, commit
6ca53a2453598804a2559a548a08424fca96434a ("resolv: Do not send queries
for non-host-names in nss_dns [BZ #24112]") is needed.

1 files changed, 136 insertions, 0 deletions

diff --git a/resolv/tst-resolv-trailing.c b/resolv/tst-resolv-trailing.c
new file mode 100644
index 0000000000..7504bdae57
--- /dev/null
+++ b/resolv/tst-resolv-trailing.c
@@ -0,0 +1,136 @@
+/* Test name resolution behavior with trailing characters.
+   Copyright (C) 2019 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <array_length.h>
+#include <netdb.h>
+#include <support/check.h>
+#include <support/check_nss.h>
+#include <support/resolv_test.h>
+#include <support/support.h>
+
+static void
+response (const struct resolv_response_context *ctx,
+          struct resolv_response_builder *b,
+          const char *qname, uint16_t qclass, uint16_t qtype)
+{
+  /* The tests are not supposed send any DNS queries.  */
+  FAIL_EXIT1 ("unexpected DNS query for %s/%d/%d", qname, qclass, qtype);
+}
+
+static int
+do_test (void)
+{
+  struct resolv_test *aux = resolv_test_start
+    ((struct resolv_redirect_config)
+     {
+       .response_callback = response,
+     });
+
+  static const char *const queries[] =
+    {
+     "192.0.2.1 ",
+     "192.0.2.2\t",
+     "192.0.2.3\n",
+     "192.0.2.4 X",
+     "192.0.2.5\tY",
+     "192.0.2.6\nZ",
+     "192.0.2. ",
+     "192.0.2.\t",
+     "192.0.2.\n",
+     "192.0.2. X",
+     "192.0.2.\tY",
+     "192.0.2.\nZ",
+     "2001:db8::1 ",
+     "2001:db8::2\t",
+     "2001:db8::3\n",
+     "2001:db8::4 X",
+     "2001:db8::5\tY",
+     "2001:db8::6\nZ",
+    };
+  for (size_t query_idx = 0; query_idx < array_length (queries); ++query_idx)
+    {
+      const char *query = queries[query_idx];
+      struct hostent storage;
+      char buf[4096];
+      struct hostent *e;
+
+      h_errno = 0;
+      TEST_VERIFY (gethostbyname (query) == NULL);
+      TEST_COMPARE (h_errno, HOST_NOT_FOUND);
+
+      h_errno = 0;
+      e = NULL;
+      TEST_COMPARE (gethostbyname_r (query, &storage, buf, sizeof (buf),
+                                     &e, &h_errno), 0);
+      TEST_VERIFY (e == NULL);
+      TEST_COMPARE (h_errno, HOST_NOT_FOUND);
+
+      h_errno = 0;
+      TEST_VERIFY (gethostbyname2 (query, AF_INET) == NULL);
+      TEST_COMPARE (h_errno, HOST_NOT_FOUND);
+
+      h_errno = 0;
+      e = NULL;
+      TEST_COMPARE (gethostbyname2_r (query, AF_INET,
+                                      &storage, buf, sizeof (buf),
+                                     &e, &h_errno), 0);
+      TEST_VERIFY (e == NULL);
+      TEST_COMPARE (h_errno, HOST_NOT_FOUND);
+
+      h_errno = 0;
+      TEST_VERIFY (gethostbyname2 (query, AF_INET6) == NULL);
+      TEST_COMPARE (h_errno, HOST_NOT_FOUND);
+
+      h_errno = 0;
+      e = NULL;
+      TEST_COMPARE (gethostbyname2_r (query, AF_INET6,
+                                      &storage, buf, sizeof (buf),
+                                     &e, &h_errno), 0);
+      TEST_VERIFY (e == NULL);
+      TEST_COMPARE (h_errno, HOST_NOT_FOUND);
+
+      static const int gai_flags[] =
+        {
+         0,
+         AI_ADDRCONFIG,
+         AI_NUMERICHOST,
+         AI_IDN,
+         AI_IDN | AI_NUMERICHOST,
+         AI_V4MAPPED,
+         AI_V4MAPPED | AI_NUMERICHOST,
+        };
+      for (size_t gai_flags_idx; gai_flags_idx < array_length (gai_flags);
+             ++gai_flags_idx)
+        {
+          struct addrinfo hints = { .ai_flags = gai_flags[gai_flags_idx], };
+          struct addrinfo *ai;
+          hints.ai_family = AF_INET;
+          TEST_COMPARE (getaddrinfo (query, "80", &hints, &ai), EAI_NONAME);
+          hints.ai_family = AF_INET6;
+          TEST_COMPARE (getaddrinfo (query, "80", &hints, &ai), EAI_NONAME);
+          hints.ai_family = AF_UNSPEC;
+          TEST_COMPARE (getaddrinfo (query, "80", &hints, &ai), EAI_NONAME);
+        }
+    };
+
+  resolv_test_end (aux);
+
+  return 0;
+}
+
+#include <support/test-driver.c>