On Wed, Mar 08, 2023 at 05:37:11PM -0500, Aaron Conole wrote:
> 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 <[email protected]>
> Signed-off-by: Aaron Conole <[email protected]>
> ---
> v1->v2: update daemon-windows for daemon_become_new_user
>
> v2->v3: update daemon-windows for daemon_start
> change log messages to be clearer
> update the manpage to provide example of why
> one would want the flag
>
> NEWS | 4 ++++
> lib/daemon-unix.c | 29 +++++++++++++++++++++--------
> lib/daemon-windows.c | 6 ++++--
> lib/daemon.c | 2 +-
> lib/daemon.h | 4 ++--
> ovsdb/ovsdb-client.c | 6 +++---
> ovsdb/ovsdb-server.c | 4 ++--
> tests/test-netflow.c | 2 +-
> tests/test-sflow.c | 2 +-
> tests/test-unixctl.c | 2 +-
> utilities/ovs-ofctl.c | 4 ++--
> utilities/ovs-testcontroller.c | 4 ++--
> vswitchd/ovs-vswitchd.8.in | 9 +++++++++
> vswitchd/ovs-vswitchd.c | 11 ++++++++++-
> 14 files changed, 63 insertions(+), 26 deletions(-)
>
> diff --git a/NEWS b/NEWS
> index 85b3496214..65f35dcdd5 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -10,6 +10,10 @@ Post-v3.1.0
> in order to create OVSDB sockets with access mode of 0770.
> - QoS:
> * Added new configuration option 'jitter' for a linux-netem QoS type.
> + - DPDK:
> + * ovs-vswitchd will keep the CAP_SYS_RAWIO capability when started
> + with the --hw-rawio-access command line option. This allows the
> + process extra privileges when mapping physical interconnect memory.
>
>
> v3.1.0 - 16 Feb 2023
> diff --git a/lib/daemon-unix.c b/lib/daemon-unix.c
> index 1a7ba427d7..dd839015ab 100644
> --- a/lib/daemon-unix.c
> +++ b/lib/daemon-unix.c
> @@ -88,7 +88,8 @@ static bool switch_user = false;
> static uid_t uid;
> static gid_t gid;
> static char *user = NULL;
> -static void daemon_become_new_user__(bool access_datapath);
> +static void daemon_become_new_user__(bool access_datapath,
> + bool access_hardware_ports);
>
> static void check_already_running(void);
> static int lock_pidfile(FILE *, int command);
> @@ -443,13 +444,13 @@ monitor_daemon(pid_t daemon_pid)
> * daemonize_complete()) or that it failed to start up (by exiting with a
> * nonzero exit code). */
> void
> -daemonize_start(bool access_datapath)
> +daemonize_start(bool access_datapath, bool access_hardware_ports)
> {
> assert_single_threaded();
> daemonize_fd = -1;
>
> if (switch_user) {
> - daemon_become_new_user__(access_datapath);
> + daemon_become_new_user__(access_datapath, access_hardware_ports);
> switch_user = false;
> }
>
> @@ -807,7 +808,8 @@ daemon_become_new_user_unix(void)
> /* Linux specific implementation of daemon_become_new_user()
> * using libcap-ng. */
> static void
> -daemon_become_new_user_linux(bool access_datapath OVS_UNUSED)
> +daemon_become_new_user_linux(bool access_datapath OVS_UNUSED,
> + bool access_hardware_ports OVS_UNUSED)
> {
> #if defined __linux__ && HAVE_LIBCAPNG
> int ret;
> @@ -827,6 +829,16 @@ daemon_become_new_user_linux(bool access_datapath
> OVS_UNUSED)
> ret = capng_update(CAPNG_ADD, cap_sets, CAP_NET_ADMIN)
> || capng_update(CAPNG_ADD, cap_sets, CAP_NET_RAW)
> || capng_update(CAPNG_ADD, cap_sets,
> CAP_NET_BROADCAST);
> +#ifdef DPDK_NETDEV
> + if (access_hardware_ports && !ret) {
> + ret = capng_update(CAPNG_ADD, cap_sets, CAP_SYS_RAWIO);
> + VLOG_INFO("The Linux capability CAP_SYS_RAWIO enabled.");
Shouldn't it be ... CAP_SYS_RAWIO is enabled. ?
> + }
> +#else
> + if (access_hardware_ports) {
> + VLOG_WARN("No driver requires Linux capability
> CAP_SYS_RAWIO, disabling it.");
Although it is not my personal preference, log messages respects
the 79 characters limit. There is an example in this same file at
line #405: "waiting until 10 seconds since last..."
Works for me. This is how I tested:
# /usr/local/share/openvswitch/scripts/ovs-ctl \
--ovs-user='openvswitch:hugetlbfs' \
--ovs-vswitchd-options='--hw-rawio-access' start
# getpcaps $(pidof ovs-vswitchd)
26923:
cap_net_bind_service,cap_net_broadcast,cap_net_admin,cap_net_raw,cap_ipc_lock,cap_sys_rawio=ep
26922:
cap_net_bind_service,cap_net_broadcast,cap_net_admin,cap_net_raw,cap_ipc_lock,cap_sys_rawio=ep
# /usr/local/share/openvswitch/scripts/ovs-ctl stop
Exiting ovs-vswitchd (26923).
Exiting ovsdb-server (26910).
# /usr/local/share/openvswitch/scripts/ovs-ctl \
--ovs-user='openvswitch:hugetlbfs' start
# getpcaps $(pidof ovs-vswitchd)
27010:
cap_net_bind_service,cap_net_broadcast,cap_net_admin,cap_net_raw,cap_ipc_lock=ep
27009:
cap_net_bind_service,cap_net_broadcast,cap_net_admin,cap_net_raw,cap_ipc_lock=ep
Thanks,
fbl
> + }
> +#endif
> }
> } else {
> ret = -1;
> @@ -854,7 +866,7 @@ daemon_become_new_user_linux(bool access_datapath
> OVS_UNUSED)
> }
>
> static void
> -daemon_become_new_user__(bool access_datapath)
> +daemon_become_new_user__(bool access_datapath, bool access_hardware_ports)
> {
> /* If vlog file has been created, change its owner to the non-root user
> * as specifed by the --user option. */
> @@ -862,7 +874,8 @@ daemon_become_new_user__(bool access_datapath)
>
> if (LINUX) {
> if (LIBCAPNG) {
> - daemon_become_new_user_linux(access_datapath);
> + daemon_become_new_user_linux(access_datapath,
> + access_hardware_ports);
> } else {
> VLOG_FATAL("%s: fail to downgrade user using libcap-ng. "
> "(libcap-ng is not configured at compile time), "
> @@ -877,11 +890,11 @@ daemon_become_new_user__(bool access_datapath)
> * However, there in case the user switch needs to be done
> * before daemonize_start(), the following API can be used. */
> void
> -daemon_become_new_user(bool access_datapath)
> +daemon_become_new_user(bool access_datapath, bool access_hardware_ports)
> {
> assert_single_threaded();
> if (switch_user) {
> - daemon_become_new_user__(access_datapath);
> + daemon_become_new_user__(access_datapath, access_hardware_ports);
> /* daemonize_start() should not switch user again. */
> switch_user = false;
> }
> diff --git a/lib/daemon-windows.c b/lib/daemon-windows.c
> index 7e5f264f5b..4e6bbe0f04 100644
> --- a/lib/daemon-windows.c
> +++ b/lib/daemon-windows.c
> @@ -498,7 +498,8 @@ make_pidfile(void)
> }
>
> void
> -daemonize_start(bool access_datapath OVS_UNUSED)
> +daemonize_start(bool access_datapath OVS_UNUSED,
> + bool access_hardware_ports OVS_UNUSED)
> {
> if (pidfile) {
> make_pidfile();
> @@ -526,7 +527,8 @@ daemonize_complete(void)
> }
>
> void
> -daemon_become_new_user(bool access_datapath OVS_UNUSED)
> +daemon_become_new_user(bool access_datapath OVS_UNUSED,
> + bool access_hardware_ports OVS_UNUSED)
> {
> }
>
> diff --git a/lib/daemon.c b/lib/daemon.c
> index 3249c5ab4b..1e1c019eb1 100644
> --- a/lib/daemon.c
> +++ b/lib/daemon.c
> @@ -48,7 +48,7 @@ get_detach(void)
> void
> daemonize(void)
> {
> - daemonize_start(false);
> + daemonize_start(false, false);
> daemonize_complete();
> }
>
> diff --git a/lib/daemon.h b/lib/daemon.h
> index 0941574963..42372d1463 100644
> --- a/lib/daemon.h
> +++ b/lib/daemon.h
> @@ -167,10 +167,10 @@ void set_detach(void);
> bool get_detach(void);
> void daemon_save_fd(int fd);
> void daemonize(void);
> -void daemonize_start(bool access_datapath);
> +void daemonize_start(bool access_datapath, bool access_hardware_ports);
> void daemonize_complete(void);
> void daemon_set_new_user(const char * user_spec);
> -void daemon_become_new_user(bool access_datapath);
> +void daemon_become_new_user(bool access_datapath, bool
> access_hardware_ports);
> void daemon_usage(void);
> void daemon_disable_self_confinement(void);
> bool daemon_should_self_confine(void);
> diff --git a/ovsdb/ovsdb-client.c b/ovsdb/ovsdb-client.c
> index f1b8d64910..bae2c5f041 100644
> --- a/ovsdb/ovsdb-client.c
> +++ b/ovsdb/ovsdb-client.c
> @@ -250,7 +250,7 @@ main(int argc, char *argv[])
> parse_options(argc, argv);
> fatal_ignore_sigpipe();
>
> - daemon_become_new_user(false);
> + daemon_become_new_user(false, false);
> if (optind >= argc) {
> ovs_fatal(0, "missing command name; use --help for help");
> }
> @@ -1392,7 +1392,7 @@ do_monitor__(struct jsonrpc *rpc, const char *database,
>
> daemon_save_fd(STDOUT_FILENO);
> daemon_save_fd(STDERR_FILENO);
> - daemonize_start(false);
> + daemonize_start(false, false);
> if (get_detach()) {
> int error;
>
> @@ -2276,7 +2276,7 @@ do_lock(struct jsonrpc *rpc, const char *method, const
> char *lock)
> getting a reply of the previous
> request. */
> daemon_save_fd(STDOUT_FILENO);
> - daemonize_start(false);
> + daemonize_start(false, false);
> lock_req_init(&lock_req, method, lock);
>
> if (get_detach()) {
> diff --git a/ovsdb/ovsdb-server.c b/ovsdb/ovsdb-server.c
> index 33ca4910d7..4fea2dbda7 100644
> --- a/ovsdb/ovsdb-server.c
> +++ b/ovsdb/ovsdb-server.c
> @@ -341,7 +341,7 @@ main(int argc, char *argv[])
> &run_command, &sync_from, &sync_exclude, &active);
> is_backup = sync_from && !active;
>
> - daemon_become_new_user(false);
> + daemon_become_new_user(false, false);
>
> /* Create and initialize 'config_tmpfile' as a temporary file to hold
> * ovsdb-server's most basic configuration, and then save our initial
> @@ -359,7 +359,7 @@ main(int argc, char *argv[])
> save_config__(config_tmpfile, &remotes, &db_filenames, sync_from,
> sync_exclude, is_backup);
>
> - daemonize_start(false);
> + daemonize_start(false, false);
>
> /* Load the saved config. */
> load_config(config_tmpfile, &remotes, &db_filenames, &sync_from,
> diff --git a/tests/test-netflow.c b/tests/test-netflow.c
> index d2322d4509..7f89cfcae0 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 460d4d6c54..3c617bdd16 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 3eadf54cd9..9e89827895 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);
> diff --git a/utilities/ovs-ofctl.c b/utilities/ovs-ofctl.c
> index eabec18a36..f81f5f759a 100644
> --- a/utilities/ovs-ofctl.c
> +++ b/utilities/ovs-ofctl.c
> @@ -173,7 +173,7 @@ main(int argc, char *argv[])
> ctx.argc = argc - optind;
> ctx.argv = argv + optind;
>
> - daemon_become_new_user(false);
> + daemon_become_new_user(false, false);
> if (read_only) {
> ovs_cmdl_run_command_read_only(&ctx, get_all_commands());
> } else {
> @@ -2127,7 +2127,7 @@ monitor_vconn(struct vconn *vconn, bool
> reply_to_echo_requests,
> int error;
>
> daemon_save_fd(STDERR_FILENO);
> - daemonize_start(false);
> + daemonize_start(false, false);
> error = unixctl_server_create(unixctl_path, &server);
> if (error) {
> ovs_fatal(error, "failed to create unixctl server");
> diff --git a/utilities/ovs-testcontroller.c b/utilities/ovs-testcontroller.c
> index b489ff5fc7..9f2fbfdf51 100644
> --- a/utilities/ovs-testcontroller.c
> +++ b/utilities/ovs-testcontroller.c
> @@ -109,7 +109,7 @@ main(int argc, char *argv[])
> parse_options(argc, argv);
> fatal_ignore_sigpipe();
>
> - daemon_become_new_user(false);
> + daemon_become_new_user(false, false);
>
> if (argc - optind < 1) {
> ovs_fatal(0, "at least one vconn argument required; "
> @@ -148,7 +148,7 @@ main(int argc, char *argv[])
> ovs_fatal(0, "no active or passive switch connections");
> }
>
> - daemonize_start(false);
> + daemonize_start(false, false);
>
> retval = unixctl_server_create(unixctl_path, &unixctl);
> if (retval) {
> diff --git a/vswitchd/ovs-vswitchd.8.in b/vswitchd/ovs-vswitchd.8.in
> index 9569265fcb..10c6e077ba 100644
> --- a/vswitchd/ovs-vswitchd.8.in
> +++ b/vswitchd/ovs-vswitchd.8.in
> @@ -81,6 +81,15 @@ unavailable or unsuccessful.
> .SS "DPDK Options"
> For details on initializing \fBovs\-vswitchd\fR to use DPDK ports,
> refer to the documentation or \fBovs\-vswitchd.conf.db\fR(5).
> +.SS "DPDK HW Access Options"
> +.IP "\fB\-\-hw\-rawio\-access\fR"
> +Tells \fBovs\-vswitchd\fR to retain the \fBCAP_SYS_RAWIO\fR capability,
> +to allow userspace drivers access to raw hardware memory. This will
> +also allow the \fBovs\-vswitchd\fR daemon to call \fBiopl()\fR and
> +\fBioperm()\fR functions as well as access memory devices to set port
> +access. This is a \fBvery\fR powerful capability, so generally only
> +enable as needed for specific hardware (for example mlx5 with full
> +hardware offload via rte_flow).
> .SS "Daemon Options"
> .ds DD \
> \fBovs\-vswitchd\fR detaches only after it has connected to the \
> diff --git a/vswitchd/ovs-vswitchd.c b/vswitchd/ovs-vswitchd.c
> index 407bfc60eb..a244d2f709 100644
> --- a/vswitchd/ovs-vswitchd.c
> +++ b/vswitchd/ovs-vswitchd.c
> @@ -60,6 +60,9 @@ VLOG_DEFINE_THIS_MODULE(vswitchd);
> * the kernel from paging any of its memory to disk. */
> static bool want_mlockall;
>
> +/* --hw-rawio-access: If set, retains CAP_SYS_RAWIO privileges. */
> +static bool hw_rawio_access;
> +
> static unixctl_cb_func ovs_vswitchd_exit;
>
> static char *parse_options(int argc, char *argv[], char **unixctl_path);
> @@ -89,7 +92,7 @@ main(int argc, char *argv[])
> remote = parse_options(argc, argv, &unixctl_path);
> fatal_ignore_sigpipe();
>
> - daemonize_start(true);
> + daemonize_start(true, hw_rawio_access);
>
> if (want_mlockall) {
> #ifdef HAVE_MLOCKALL
> @@ -169,6 +172,7 @@ parse_options(int argc, char *argv[], char
> **unixctl_pathp)
> OPT_DPDK,
> SSL_OPTION_ENUMS,
> OPT_DUMMY_NUMA,
> + OPT_HW_RAWIO_ACCESS,
> };
> static const struct option long_options[] = {
> {"help", no_argument, NULL, 'h'},
> @@ -185,6 +189,7 @@ parse_options(int argc, char *argv[], char
> **unixctl_pathp)
> {"disable-system-route", no_argument, NULL,
> OPT_DISABLE_SYSTEM_ROUTE},
> {"dpdk", optional_argument, NULL, OPT_DPDK},
> {"dummy-numa", required_argument, NULL, OPT_DUMMY_NUMA},
> + {"hw-rawio-access", no_argument, NULL, OPT_HW_RAWIO_ACCESS},
> {NULL, 0, NULL, 0},
> };
> char *short_options =
> ovs_cmdl_long_options_to_short_options(long_options);
> @@ -249,6 +254,10 @@ parse_options(int argc, char *argv[], char
> **unixctl_pathp)
> ovs_numa_set_dummy(optarg);
> break;
>
> + case OPT_HW_RAWIO_ACCESS:
> + hw_rawio_access = true;
> + break;
> +
> default:
> abort();
> }
> --
> 2.39.2
>
> _______________________________________________
> dev mailing list
> [email protected]
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
--
fbl
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