Return NULL if we fail to create a BIO in the demos/quicserver

Strictly speaking the previous code was still correct since BIO_set_fd
is tolerant of a NULL BIO. But this way is more clear.

Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Hugo Landau <hlandau@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/21950)

2 files changed, 8 insertions, 4 deletions

diff --git a/doc/man7/ossl-guide-quic-client-block.pod b/doc/man7/ossl-guide-quic-client-block.pod
index 4cf8bdd3b8..fc8912086d 100644
--- a/doc/man7/ossl-guide-quic-client-block.pod
+++ b/doc/man7/ossl-guide-quic-client-block.pod
@@ -165,10 +165,12 @@ associate it with a BIO object:
 
     BIO *bio;
 
-    /* Create a BIO to wrap the socket*/
+    /* Create a BIO to wrap the socket */
     bio = BIO_new(BIO_s_datagram());
-    if (bio == NULL)
+    if (bio == NULL) {
         BIO_closesocket(sock);
+        return NULL;
+    }
 
     /*
      * Associate the newly created BIO with the underlying socket. By
diff --git a/doc/man7/ossl-guide-tls-client-block.pod b/doc/man7/ossl-guide-tls-client-block.pod
index 236553fafd..865a5353b3 100644
--- a/doc/man7/ossl-guide-tls-client-block.pod
+++ b/doc/man7/ossl-guide-tls-client-block.pod
@@ -222,10 +222,12 @@ BIO object:
 
     BIO *bio;
 
-    /* Create a BIO to wrap the socket*/
+    /* Create a BIO to wrap the socket */
     bio = BIO_new(BIO_s_socket());
-    if (bio == NULL)
+    if (bio == NULL) {
         BIO_closesocket(sock);
+        return NULL;
+    }
 
     /*
      * Associate the newly created BIO with the underlying socket. By