net/mbedtls_net_connect: Preventing double close problem

In the test examples and real usage scenarios, 'mbedtls_net_free' is called after 'mbedtls_net_connect' fails, which will cause the problem of double close the same fd. It is possible to close this closed fd which has been applied by other link.

Signed-off-by: makejian <[email protected]>

ChangeLog.d/replace-close-with-mbedtls_net_close.txt

@@ -0,0 +1,4 @@
+Bugfix
+   * Use 'mbedtls_net_close' instead of 'close' in 'mbedtls_net_bind'
+     and 'mbedtls_net_connect' to prevent possible double close fd
+     problems. Fixes #9711.

library/net_sockets.c

@@ -190,7 +190,7 @@ int mbedtls_net_connect(mbedtls_net_context *ctx, const char *host,
             break;
         }
 
-        close(ctx->fd);
+        mbedtls_net_close(ctx);
         ret = MBEDTLS_ERR_NET_CONNECT_FAILED;
     }
 
@@ -237,21 +237,21 @@ int mbedtls_net_bind(mbedtls_net_context *ctx, const char *bind_ip, const char *
         n = 1;
         if (setsockopt(ctx->fd, SOL_SOCKET, SO_REUSEADDR,
                        (const char *) &n, sizeof(n)) != 0) {
-            close(ctx->fd);
+            mbedtls_net_close(ctx);
             ret = MBEDTLS_ERR_NET_SOCKET_FAILED;
             continue;
         }
 
         if (bind(ctx->fd, cur->ai_addr, MSVC_INT_CAST cur->ai_addrlen) != 0) {
-            close(ctx->fd);
+            mbedtls_net_close(ctx);
             ret = MBEDTLS_ERR_NET_BIND_FAILED;
             continue;
         }
 
         /* Listen only makes sense for TCP */
         if (proto == MBEDTLS_NET_PROTO_TCP) {
             if (listen(ctx->fd, MBEDTLS_NET_LISTEN_BACKLOG) != 0) {
-                close(ctx->fd);
+                mbedtls_net_close(ctx);
                 ret = MBEDTLS_ERR_NET_LISTEN_FAILED;
                 continue;
             }