[Virtio-fs] [PATCH] virtiofsd: Add clock_gettime() to seccomp white list

[Masayoshi Mizuma]

From: Masayoshi Mizuma <m.mizuma at jp.fujitsu.com>

virtiofsd receives SIGSYS signal while qemu is shutting down.

  ]# ./virtiofsd -d -o vhost_user_socket=/tmp/vhostqemu0 \
     -o source=/tmp/share0 -o cache=auto
  ...
  virtio_send_msg: elem 0: with 1 in desc of length 16
  virtio_loop: Got VU event
  fv_queue_set_started: qidx=0 started=0
  fv_queue_thread: kill event on queue 0 - quitting
  fv_remove_watch: TODO! fd=9
  virtio_loop: Waiting for VU event
  Bad system call (core dumped)
  ]#

That is because virtiofsd calls clock_gettime() via glib
function and clock_gettime() isn't in seccomp white list,
so virtiofsd receives SIGSYS.
The glib function is called to manage the pool thread.
The calltrace is like as:

  #0  clock_gettime ()
  #1  g_get_monotonic_time ()
  #2  g_async_queue_timeout_pop ()
  #3  g_thread_pool_wait_for_new_pool ()
  #4  g_thread_pool_thread_proxy ()
  #5  g_thread_proxy ()
  #6  start_thread ()
  #7  clone ()

Add clock_gettime() to seccomp white list.

Signed-off-by: Masayoshi Mizuma <m.mizuma at jp.fujitsu.com>
---
 contrib/virtiofsd/seccomp.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/contrib/virtiofsd/seccomp.c b/contrib/virtiofsd/seccomp.c
index f815ea5bf9..b78056b13f 100644
--- a/contrib/virtiofsd/seccomp.c
+++ b/contrib/virtiofsd/seccomp.c
@@ -19,6 +19,7 @@ static const int syscall_whitelist[] = {
     SCMP_SYS(brk),
     SCMP_SYS(capget), /* For CAP_FSETID */
     SCMP_SYS(capset),
+    SCMP_SYS(clock_gettime),
     SCMP_SYS(clone),
     SCMP_SYS(close),
     SCMP_SYS(copy_file_range),
-- 
2.18.1