BIO_lookup_ex: use AI_ADDRCONFIG only if explicit host name is given

The flag only affects which record types are queried via DNS (A or
AAAA, or both).  When node is NULL and AF_UNSPEC is used, it prevents
getaddrinfo returning the right address associated with the loopback
interface.

Signed-off-by: Daiki Ueno <dueno@redhat.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
(Merged from https://github.com/openssl/openssl/pull/16033)

diff --git a/crypto/bio/bio_addr.c b/crypto/bio/bio_addr.c
index 0efbc3cb44a948c15ba9dd83747a559b8966cee4..d18c849ade158b41f591b5fe17560d5153c8c117 100644 (file)
--- a/crypto/bio/bio_addr.c
+++ b/crypto/bio/bio_addr.c
@@ -696,7 +696,7 @@ int BIO_lookup_ex(const char *host, const char *service, int lookup_type,
         hints.ai_protocol = protocol;
 # ifdef AI_ADDRCONFIG
 #  ifdef AF_UNSPEC
-        if (family == AF_UNSPEC)
+        if (host != NULL && family == AF_UNSPEC)
 #  endif
             hints.ai_flags |= AI_ADDRCONFIG;
 # endif