virtio-devices: seccomp: Add seccomp filters for iommu thread

This patch enables the seccomp filters for the iommu worker thread.

Partially fixes: #925

Signed-off-by: Bo Chen <chen.bo@intel.com>

virtio-devices/src/iommu.rs

@@ -8,9 +8,11 @@ use super::{
     EpollHelperHandler, Queue, VirtioDevice, VirtioDeviceType, EPOLL_HELPER_EVENT_LAST,
     VIRTIO_F_VERSION_1,
 };
+use crate::seccomp_filters::{get_seccomp_filter, Thread};
 use crate::{DmaRemapping, VirtioInterrupt, VirtioInterruptType};
 use anyhow::anyhow;
 use libc::EFD_NONBLOCK;
+use seccomp::{SeccompAction, SeccompFilter};
 use std::collections::BTreeMap;
 use std::fmt::{self, Display};
 use std::io;
@@ -748,6 +750,7 @@ pub struct Iommu {
     epoll_threads: Option<Vec<thread::JoinHandle<()>>>,
     paused: Arc<AtomicBool>,
     paused_sync: Arc<Barrier>,
+    seccomp_action: SeccompAction,
 }
 
 #[derive(Serialize, Deserialize)]
@@ -759,7 +762,7 @@ struct IommuState {
 }
 
 impl Iommu {
-    pub fn new(id: String) -> io::Result<(Self, Arc<IommuMapping>)> {
+    pub fn new(id: String, seccomp_action: SeccompAction) -> io::Result<(Self, Arc<IommuMapping>)> {
         let config = VirtioIommuConfig {
             page_size_mask: VIRTIO_IOMMU_PAGE_SIZE_MASK,
             probe_size: PROBE_PROP_SIZE,
@@ -789,6 +792,7 @@ impl Iommu {
                 epoll_threads: None,
                 paused: Arc::new(AtomicBool::new(false)),
                 paused_sync: Arc::new(Barrier::new(2)),
+                seccomp_action,
             },
             mapping,
         ))
@@ -963,10 +967,16 @@ impl VirtioDevice for Iommu {
         let paused = self.paused.clone();
         let paused_sync = self.paused_sync.clone();
         let mut epoll_threads = Vec::new();
+        // Retrieve seccomp filter for virtio_iommu thread
+        let virtio_iommu_seccomp_filter =
+            get_seccomp_filter(&self.seccomp_action, Thread::VirtioIommu)
+                .map_err(ActivateError::CreateSeccompFilter)?;
         thread::Builder::new()
             .name("virtio_iommu".to_string())
             .spawn(move || {
-                if let Err(e) = handler.run(paused, paused_sync) {
+                if let Err(e) = SeccompFilter::apply(virtio_iommu_seccomp_filter) {
+                    error!("Error applying seccomp filter: {:?}", e);
+                } else if let Err(e) = handler.run(paused, paused_sync) {
                     error!("Error running worker: {:?}", e);
                 }
             })

virtio-devices/src/seccomp_filters.rs

@@ -12,6 +12,7 @@ use std::convert::TryInto;
 pub enum Thread {
     VirtioBlk,
     VirtioConsole,
+    VirtioIommu,
     VirtioNet,
     VirtioPmem,
     VirtioRng,
@@ -81,6 +82,20 @@ fn virtio_console_thread_rules() -> Result<Vec<SyscallRuleSet>, Error> {
     ])
 }
 
+fn virtio_iommu_thread_rules() -> Result<Vec<SyscallRuleSet>, Error> {
+    Ok(vec![
+        allow_syscall(libc::SYS_epoll_create1),
+        allow_syscall(libc::SYS_epoll_ctl),
+        allow_syscall(libc::SYS_dup),
+        allow_syscall(libc::SYS_epoll_pwait),
+        #[cfg(target_arch = "x86_64")]
+        allow_syscall(libc::SYS_epoll_wait),
+        allow_syscall(libc::SYS_futex),
+        allow_syscall(libc::SYS_read),
+        allow_syscall(libc::SYS_write),
+    ])
+}
+
 fn virtio_net_thread_rules() -> Result<Vec<SyscallRuleSet>, Error> {
     Ok(vec![
         allow_syscall(libc::SYS_close),
@@ -150,6 +165,7 @@ fn get_seccomp_filter_trap(thread_type: Thread) -> Result<SeccompFilter, Error>
     let rules = match thread_type {
         Thread::VirtioBlk => virtio_blk_thread_rules()?,
         Thread::VirtioConsole => virtio_console_thread_rules()?,
+        Thread::VirtioIommu => virtio_iommu_thread_rules()?,
         Thread::VirtioNet => virtio_net_thread_rules()?,
         Thread::VirtioPmem => virtio_pmem_thread_rules()?,
         Thread::VirtioRng => virtio_rng_thread_rules()?,
@@ -165,6 +181,7 @@ fn get_seccomp_filter_log(thread_type: Thread) -> Result<SeccompFilter, Error> {
     let rules = match thread_type {
         Thread::VirtioBlk => virtio_blk_thread_rules()?,
         Thread::VirtioConsole => virtio_console_thread_rules()?,
+        Thread::VirtioIommu => virtio_iommu_thread_rules()?,
         Thread::VirtioNet => virtio_net_thread_rules()?,
         Thread::VirtioPmem => virtio_pmem_thread_rules()?,
         Thread::VirtioRng => virtio_rng_thread_rules()?,

vmm/src/device_manager.rs

@@ -1009,7 +1009,8 @@ impl DeviceManager {
             let iommu_id = String::from(IOMMU_DEVICE_NAME);
 
             let (iommu_device, iommu_mapping) = if self.config.lock().unwrap().iommu {
-                let (device, mapping) = virtio_devices::Iommu::new(iommu_id.clone())
+                let (device, mapping) =
+                    virtio_devices::Iommu::new(iommu_id.clone(), self.seccomp_action.clone())
                         .map_err(DeviceManagerError::CreateVirtioIommu)?;
                 let device = Arc::new(Mutex::new(device));
                 self.iommu_device = Some(Arc::clone(&device));