Re: [PATCH][BZ 21295] getaddrinfo: do not overwrite IPv6 IPs with IPv4 when using AF_UNSPEC

[Florian Weimer <fweimer at redhat dot com>]

On 07/06/2017 11:02 AM, Stefan Liebler wrote:
> I've recognized the test-fail resolv/tst-resolv-basic on some but not
> all machines of mine on different architectures s390, intel, power and
> according to 2.26 release page, Joseph also recognized it on his arm,
> mips, power32 machines:
> warning: could not become root outside namespace (Operation not permitted)
> warning: unshare (CLONE_NEWUTS) failed: Operation not permitted
> warning: could not enter network namespace
> error: addrinfo comparison failure
> query: www.example:80 [10]/0x18
> --- expected
> +++ actual
> @@ -1,3 +1,3 @@
>  flags: AI_V4MAPPED AI_ALL
> -address: STREAM/TCP 2001:db8::1 80
>  address: STREAM/TCP ::ffff:192.0.2.17 80
> +address: STREAM/TCP 2001:db8::1 80
> error: addrinfo comparison failure
> query: t.www.example:80 [10]/0x18

I saw this as well, but have not figured out whether it's due to UDP
response ordering or system configuration if (network) namespaces are
not in effect.

Would you please try the attached patch?  Thanks.

Florian

resolv: Deal with non-deterministic address order in tst-resolv-basic

2017-07-06  Florian Weimer  <fw@deneb.enyo.de>

	* resolv/tst-resolv-basic.c (test_bug_21295): New function.
	(do_test): Call it.

diff --git a/resolv/tst-resolv-basic.c b/resolv/tst-resolv-basic.c
index 3dfa165..64eedbb 100644
--- a/resolv/tst-resolv-basic.c
+++ b/resolv/tst-resolv-basic.c
@@ -22,6 +22,7 @@
 #include <string.h>
 #include <support/check.h>
 #include <support/check_nss.h>
+#include <support/format_nss.h>
 #include <support/resolv_test.h>
 #include <support/support.h>
 
@@ -204,6 +205,68 @@ check_ai (const char *name, const char *service,
                          expected);
 }
 
+/* Test for bug 21295: getaddrinfo used to discard address information
+   instead of merging it.  */
+static void
+test_bug_21295 (void)
+{
+  /* The address order is unpredictable.  There are two factors which
+     contribute to that: The stub resolver does not perform proper
+     response matching for A/AAAA queries (an A response could be
+     associated with an AAAA query and vice versa), and without
+     namespaces, system configuration could affect address
+     ordering.  */
+  for (int do_tcp = 0; do_tcp < 2; ++do_tcp)
+    {
+      const struct addrinfo hints =
+        {
+          .ai_family = AF_INET6,
+          .ai_socktype = SOCK_STREAM,
+          .ai_flags = AI_V4MAPPED | AI_ALL,
+        };
+      const char *qname;
+      if (do_tcp)
+        qname = "t.www.example";
+      else
+        qname = "www.example";
+      struct addrinfo *ai = NULL;
+      int ret = getaddrinfo (qname, "80", &hints, &ai);
+      TEST_VERIFY_EXIT (ret == 0);
+
+      const char *expected_a;
+      const char *expected_b;
+      if (do_tcp)
+        {
+          expected_a = "flags: AI_V4MAPPED AI_ALL\n"
+            "address: STREAM/TCP 2001:db8::3 80\n"
+            "address: STREAM/TCP ::ffff:192.0.2.19 80\n";
+          expected_b = "flags: AI_V4MAPPED AI_ALL\n"
+            "address: STREAM/TCP ::ffff:192.0.2.19 80\n"
+            "address: STREAM/TCP 2001:db8::3 80\n";
+        }
+      else
+        {
+          expected_a = "flags: AI_V4MAPPED AI_ALL\n"
+            "address: STREAM/TCP 2001:db8::1 80\n"
+            "address: STREAM/TCP ::ffff:192.0.2.17 80\n";
+          expected_b = "flags: AI_V4MAPPED AI_ALL\n"
+            "address: STREAM/TCP ::ffff:192.0.2.17 80\n"
+            "address: STREAM/TCP 2001:db8::1 80\n";
+        }
+
+      char *actual = support_format_addrinfo (ai, ret);
+      if (!(strcmp (actual, expected_a) == 0
+            || strcmp (actual, expected_b) == 0))
+        {
+          support_record_failure ();
+          printf ("error: %s: unexpected response (TCP: %d):\n%s\n",
+                  __func__, do_tcp, actual);
+        }
+      free (actual);
+      freeaddrinfo (ai);
+    }
+}
+
 static int
 do_test (void)
 {
@@ -398,21 +461,7 @@ do_test (void)
   check_ai ("t.nxdomain.example", "80", AF_INET6,
             "error: Name or service not known\n");
 
-  /* Test for bug 21295.  */
-  check_ai_hints ("www.example", "80",
-                  (struct addrinfo) { .ai_family = AF_INET6,
-                      .ai_socktype = SOCK_STREAM,
-                      .ai_flags = AI_V4MAPPED | AI_ALL, },
-                  "flags: AI_V4MAPPED AI_ALL\n"
-                  "address: STREAM/TCP 2001:db8::1 80\n"
-                  "address: STREAM/TCP ::ffff:192.0.2.17 80\n");
-  check_ai_hints ("t.www.example", "80",
-                  (struct addrinfo) { .ai_family = AF_INET6,
-                      .ai_socktype = SOCK_STREAM,
-                      .ai_flags = AI_V4MAPPED | AI_ALL, },
-                  "flags: AI_V4MAPPED AI_ALL\n"
-                  "address: STREAM/TCP 2001:db8::3 80\n"
-                  "address: STREAM/TCP ::ffff:192.0.2.19 80\n");
+  test_bug_21295 ();
 
   resolv_test_end (aux);