virtfs-proxy: Fix possible overflow

It's detected by coverity. The socket name specified
should fit in the sockadd_un.sun_path. If not abort.

Signed-off-by: Shannon Zhao <zhaoshenglong@huawei.com>
Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

fsdev/virtfs-proxy-helper.c

@@ -738,6 +738,7 @@ static int proxy_socket(const char *path, uid_t uid, gid_t gid)
         return -1;
     }
 
+    g_assert(strlen(path) < sizeof(proxy.sun_path));
     sock = socket(AF_UNIX, SOCK_STREAM, 0);
     if (sock < 0) {
         do_perror("socket");

hw/9pfs/virtio-9p-proxy.c

@@ -1100,6 +1100,10 @@ static int connect_namedsocket(const char *path)
     int sockfd, size;
     struct sockaddr_un helper;
 
+    if (strlen(path) >= sizeof(helper.sun_path)) {
+        fprintf(stderr, "Socket name too large\n");
+        return -1;
+    }
     sockfd = socket(AF_UNIX, SOCK_STREAM, 0);
     if (sockfd < 0) {
         fprintf(stderr, "failed to create socket: %s\n", strerror(errno));