On 4/16/20 6:49 PM, Stefan Hajnoczi wrote:
All this process does is wait for its child. No capabilities are needed.Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com> --- tools/virtiofsd/passthrough_ll.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/tools/virtiofsd/passthrough_ll.c b/tools/virtiofsd/passthrough_ll.c index af97ba1c41..0c3f33b074 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -2530,6 +2530,17 @@ static void print_capabilities(void) printf("}\n"); }+/*+ * Drop all Linux capabilities because the wait parent process only needs to + * sit in waitpid(2) and terminate. + */ +static void setup_wait_parent_capabilities(void) +{ + capng_setpid(syscall(SYS_gettid));
Maybe worth a /* Drop all capabilities */ comment here. Reviewed-by: Philippe Mathieu-Daudé <phi...@redhat.com>
+ capng_clear(CAPNG_SELECT_BOTH); + capng_apply(CAPNG_SELECT_BOTH); +} + /* * Move to a new mount, net, and pid namespaces to isolate this process. */ @@ -2561,6 +2572,8 @@ static void setup_namespaces(struct lo_data *lo, struct fuse_session *se) pid_t waited; int wstatus;+ setup_wait_parent_capabilities();+ /* The parent waits for the child */ do { waited = waitpid(child, &wstatus, 0);
