dpdk: Allow retaining CAP_SYS_RAWIO privileges.

Open vSwitch generally tries to let the underlying operating system
managed the low level details of hardware, for example DMA mapping,
bus arbitration, etc.  However, when using DPDK, the underlying
operating system yields control of many of these details to userspace
for management.

In the case of some DPDK port drivers, configuring rte_flow or even
allocating resources may require access to iopl/ioperm calls, which
are guarded by the CAP_SYS_RAWIO privilege on linux systems.  These
calls are dangerous, and can allow a process to completely compromise
a system.  However, they are needed in the case of some userspace
driver code which manages the hardware (for example, the mlx
implementation of backend support for rte_flow).

Here, we create an opt-in flag passed to the command line to allow
this access.  We need to do this before ever accessing the database,
because we want to drop all privileges asap, and cannot wait for
a connection to the database to be established and functional before
dropping.  There may be distribution specific ways to do capability
management as well (using for example, systemd), but they are not
as universal to the vswitchd as a flag.

Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Aaron Conole <aconole@redhat.com>
Acked-by: Flavio Leitner <fbl@sysclose.org>
Acked-by: Gaetan Rivet <gaetanr@nvidia.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>

3 files changed, 3 insertions, 3 deletions

diff --git a/tests/test-netflow.c b/tests/test-netflow.c
index d2322d450..7f89cfcae 100644
--- a/tests/test-netflow.c
+++ b/tests/test-netflow.c
@@ -195,7 +195,7 @@ test_netflow_main(int argc, char *argv[])
     }
 
     daemon_save_fd(STDOUT_FILENO);
-    daemonize_start(false);
+    daemonize_start(false, false);
 
     error = unixctl_server_create(NULL, &server);
     if (error) {
diff --git a/tests/test-sflow.c b/tests/test-sflow.c
index 460d4d6c5..3c617bdd1 100644
--- a/tests/test-sflow.c
+++ b/tests/test-sflow.c
@@ -709,7 +709,7 @@ test_sflow_main(int argc, char *argv[])
     }
 
     daemon_save_fd(STDOUT_FILENO);
-    daemonize_start(false);
+    daemonize_start(false, false);
 
     error = unixctl_server_create(NULL, &server);
     if (error) {
diff --git a/tests/test-unixctl.c b/tests/test-unixctl.c
index 3eadf54cd..9e8982789 100644
--- a/tests/test-unixctl.c
+++ b/tests/test-unixctl.c
@@ -83,7 +83,7 @@ test_unixctl_main(int argc, char *argv[])
     fatal_ignore_sigpipe();
     parse_options(&argc, &argv, &unixctl_path);
 
-    daemonize_start(false);
+    daemonize_start(false, false);
     int retval = unixctl_server_create(unixctl_path, &unixctl);
     if (retval) {
         exit(EXIT_FAILURE);