Merge branch 'tor-gitlab/mr/556' into maint-0.4.5

diff --cc src/lib/sandbox/sandbox.c
index fc90dbe0629cdf11b87c1b2cff5cde431da36d59,df676fad2f7eb3fa52457cba6b7f9135d9b2456e..e6e556eb598983659f3cb166aebf7a382e77ece2
--- 1/src/lib/sandbox/sandbox.c
--- 2/src/lib/sandbox/sandbox.c
+++ b/src/lib/sandbox/sandbox.c
@@@ -151,7 -144,9 +151,10 @@@ static int filter_nopar_gen[] = 
      SCMP_SYS(clock_gettime),
      SCMP_SYS(close),
      SCMP_SYS(clone),
 +    SCMP_SYS(dup),
+ #ifdef __NR_clone3
+     SCMP_SYS(clone3),
+ #endif
      SCMP_SYS(epoll_create),
      SCMP_SYS(epoll_wait),
  #ifdef __NR_epoll_pwait