From 78152453940967f9ece9fe3ffc5017c669d6ec28 Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Tue, 5 May 2020 16:36:00 +0100 Subject: [PATCH 9/9] virtiofsd: drop all capabilities in the wait parent process MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Dr. David Alan Gilbert Message-id: <20200505163600.22956-8-dgilbert@redhat.com> Patchwork-id: 96274 O-Subject: [RHEL-AV-8.2.1 qemu-kvm PATCH 7/7] virtiofsd: drop all capabilities in the wait parent process Bugzilla: 1817445 RH-Acked-by: Stefan Hajnoczi RH-Acked-by: Max Reitz RH-Acked-by: Philippe Mathieu-Daudé RH-Acked-by: Michael S. Tsirkin From: Stefan Hajnoczi All this process does is wait for its child. No capabilities are needed. Signed-off-by: Stefan Hajnoczi Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Dr. David Alan Gilbert (cherry picked from commit 66502bbca37ca7a3bfa57e82cfc03b89a7a11eae) Signed-off-by: Danilo C. L. de Paula --- 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 6358874..f41a6b0 100644 --- a/tools/virtiofsd/passthrough_ll.c +++ b/tools/virtiofsd/passthrough_ll.c @@ -2535,6 +2535,17 @@ static void print_capabilities(void) } /* + * 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)); + capng_clear(CAPNG_SELECT_BOTH); + capng_apply(CAPNG_SELECT_BOTH); +} + +/* * Move to a new mount, net, and pid namespaces to isolate this process. */ static void setup_namespaces(struct lo_data *lo, struct fuse_session *se) @@ -2567,6 +2578,8 @@ 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); -- 1.8.3.1