knsupdate: fix segfault due to NULL pointer access when sending an update

diff --git a/src/utils/common/netio.c b/src/utils/common/netio.c
index 2fdb142b4ad37ac92b5684c4c03efdeffd9428ad..56017b1b95ab8425cdc9a97bbb044b0e5a496b38 100644 (file)
--- a/src/utils/common/netio.c
+++ b/src/utils/common/netio.c
@@ -222,6 +222,12 @@ int net_init(const srv_info_t      *local,
        net->proxy.src = proxy_src;
        net->proxy.dst = proxy_dst;
 
+       if ((bool)(proxy_src == NULL) != (bool)(proxy_dst == NULL) ||
+           (proxy_src != NULL && proxy_src->sa_family != proxy_dst->sa_family)) {
+               net_clean(net);
+               return KNOT_EINVAL;
+       }
+
        // Prepare for TLS.
        if (tls_params != NULL && tls_params->enable) {
                int ret = 0;
@@ -584,7 +590,7 @@ int net_send(const net_t *net, const uint8_t *buf, const size_t buf_len)
                        .msg_iovlen = 1
                };
 
-               if (net->proxy.src->sa_family && net->proxy.dst->sa_family) {
+               if (net->proxy.src != NULL && net->proxy.src->sa_family != 0) {
                        int ret = proxyv2_write_header(proxy_buf, sizeof(proxy_buf),
                                                       SOCK_DGRAM, net->proxy.src,
                                                       net->proxy.dst);
@@ -638,7 +644,7 @@ int net_send(const net_t *net, const uint8_t *buf, const size_t buf_len)
                        .msg_iovlen = 2
                };
 
-               if (net->proxy.src->sa_family && net->proxy.dst->sa_family) {
+               if (net->proxy.src != NULL && net->proxy.src->sa_family != 0) {
                        int ret = proxyv2_write_header(proxy_buf, sizeof(proxy_buf),
                                                       SOCK_STREAM, net->proxy.src,
                                                       net->proxy.dst);