agent: support sealed secret as file in kata

Fixes: #7555

Signed-off-by: Linda Yu <linda.yu@intel.com>

src/agent/src/cdh.rs

@@ -8,24 +8,42 @@
 // https://github.com/confidential-containers/guest-components/tree/main/confidential-data-hub
 
 use anyhow::{anyhow, Result};
+use oci::{Mount, Spec};
 use protocols::{
     sealed_secret, sealed_secret_ttrpc_async, sealed_secret_ttrpc_async::SealedSecretServiceClient,
 };
+use std::fs;
+use std::os::unix::fs::symlink;
+use std::path::Path;
 const CDH_ADDR: &str = "unix:///run/confidential-containers/cdh.sock";
+const SECRETS_DIR: &str = "/run/secrets/";
+const SEALED_SECRET_TIMEOUT: i64 = 50 * 1000 * 1000 * 1000;
+
+// Convenience function to obtain the scope logger.
+fn sl() -> slog::Logger {
+    slog_scope::logger()
+}
 
 #[derive(Clone)]
 pub struct CDHClient {
-    sealed_secret_client: SealedSecretServiceClient,
+    sealed_secret_client: Option<SealedSecretServiceClient>,
 }
 
 impl CDHClient {
     pub fn new() -> Result<Self> {
-        let c = ttrpc::asynchronous::Client::connect(CDH_ADDR)?;
-        let ssclient = sealed_secret_ttrpc_async::SealedSecretServiceClient::new(c);
+        let c = ttrpc::asynchronous::Client::connect(CDH_ADDR);
+        match c {
+            Ok(v) => {
+                let ssclient = sealed_secret_ttrpc_async::SealedSecretServiceClient::new(v);
                 Ok(CDHClient {
-            sealed_secret_client: ssclient,
+                    sealed_secret_client: Some(ssclient),
                 })
             }
+            Err(_) => Ok(CDHClient {
+                sealed_secret_client: None,
+            }),
+        }
+    }
 
     pub async fn unseal_secret_async(
         &self,
@@ -33,27 +51,25 @@ impl CDHClient {
     ) -> Result<sealed_secret::UnsealSecretOutput> {
         let secret = sealed
             .strip_prefix("sealed.")
-            .ok_or(anyhow!("strip_prefix sealed. failed"))?;
+            .ok_or(anyhow!("strip_prefix \"sealed.\" failed"))?;
         let mut input = sealed_secret::UnsealSecretInput::new();
         input.set_secret(secret.into());
         let unseal = self
             .sealed_secret_client
-            .unseal_secret(
-                ttrpc::context::with_timeout(50 * 1000 * 1000 * 1000),
-                &input,
-            )
+            .as_ref()
+            .ok_or(anyhow!("unwrap sealed_secret_client failed"))?
+            .unseal_secret(ttrpc::context::with_timeout(SEALED_SECRET_TIMEOUT), &input)
             .await?;
         Ok(unseal)
     }
 
     pub async fn unseal_env(&self, env: &str) -> Result<String> {
-        let (key, value) = env.split_once('=').unwrap();
+        let (key, value) = env.split_once('=').unwrap_or(("", ""));
         if value.starts_with("sealed.") {
             let unsealed_value = self.unseal_secret_async(value).await;
             match unsealed_value {
                 Ok(v) => {
-                    let plain_env =
-                        format!("{}={}", key, std::str::from_utf8(&v.plaintext).unwrap());
+                    let plain_env = format!("{}={}", key, std::str::from_utf8(&v.plaintext)?);
                     return Ok(plain_env);
                 }
                 Err(e) => {
@@ -63,6 +79,81 @@ impl CDHClient {
         }
         Ok((*env.to_owned()).to_string())
     }
+
+    pub async fn unseal_file(&self, sealed_source_path: &String) -> Result<()> {
+        if !Path::new(sealed_source_path).exists() {
+            info!(
+                sl(),
+                "sealed source path {:?} does not exist", sealed_source_path
+            );
+            return Ok(());
+        }
+
+        for entry in fs::read_dir(sealed_source_path)? {
+            let entry = entry?;
+
+            if !entry.file_type()?.is_symlink()
+                && !fs::metadata(entry.path())?.file_type().is_file()
+            {
+                info!(
+                    sl(),
+                    "skipping sealed source entry {:?} because its file type is {:?}",
+                    entry,
+                    entry.file_type()?
+                );
+                continue;
+            }
+
+            let target_path = fs::canonicalize(&entry.path())?;
+            info!(sl(), "sealed source entry target path: {:?}", target_path);
+            if !target_path.is_file() {
+                info!(sl(), "sealed source is not a file: {:?}", target_path);
+                continue;
+            }
+
+            let secret_name = entry.file_name();
+            let contents = fs::read_to_string(&target_path)?;
+            if contents.starts_with("sealed.") {
+                info!(sl(), "sealed source entry found: {:?}", target_path);
+                let unsealed_filename = SECRETS_DIR.to_string()
+                    + secret_name
+                        .as_os_str()
+                        .to_str()
+                        .ok_or(anyhow!("create unsealed_filename failed"))?;
+                let unsealed_value = self.unseal_secret_async(&contents).await?;
+                fs::write(&unsealed_filename, unsealed_value.plaintext)?;
+                fs::remove_file(&entry.path())?;
+                symlink(unsealed_filename, &entry.path())?;
+            }
+        }
+        Ok(())
+    }
+
+    pub fn create_sealed_secret_mounts(&self, spec: &mut Spec) -> Result<Vec<String>> {
+        let mut sealed_source_path: Vec<String> = vec![];
+        for m in spec.mounts.iter_mut() {
+            if let Some(unsealed_mount_point) = m.destination.strip_prefix("/sealed") {
+                info!(
+                    sl(),
+                    "sealed mount destination: {:?} source: {:?}", m.destination, m.source
+                );
+                sealed_source_path.push(m.source.clone());
+                m.destination = unsealed_mount_point.to_string();
+            }
+        }
+
+        if sealed_source_path.len() > 0 {
+            let sealed_mounts = Mount {
+                destination: SECRETS_DIR.to_string(),
+                r#type: "bind".to_string(),
+                source: SECRETS_DIR.to_string(),
+                options: vec!["bind".to_string()],
+            };
+            spec.mounts.push(sealed_mounts);
+        }
+        fs::create_dir_all(SECRETS_DIR)?;
+        Ok(sealed_source_path)
+    }
 } /* end of impl CDHClient */
 
 #[cfg(test)]
@@ -145,5 +236,6 @@ mod tests {
         assert_eq!(unchanged_env, String::from("key=testdata"));
 
         rt.shutdown_background();
+        std::thread::sleep(std::time::Duration::from_secs(2));
     }
 }

src/agent/src/rpc.rs

@@ -209,24 +209,27 @@ impl AgentService {
         // cannot predict everything from the caller.
         add_devices(&req.devices, &mut oci, &self.sandbox).await?;
 
-        if cfg!(feature = "sealed-secret") {
+        #[cfg(feature = "sealed-secret")]
+        let mut sealed_source_path = {
             let process = oci
                 .process
                 .as_mut()
                 .ok_or_else(|| anyhow!("Spec didn't contain process field"))?;
 
-            for env in process.env.iter_mut() {
             let client = self
                 .cdh_client
                 .as_ref()
                 .ok_or(anyhow!("get cdh_client failed"))?;
+            for env in process.env.iter_mut() {
                 let unsealed_env = client
                     .unseal_env(env)
                     .await
                     .map_err(|e| anyhow!("unseal env failed: {:?}", e))?;
                 *env = unsealed_env.to_string();
             }
-        }
+
+            client.create_sealed_secret_mounts(&mut oci)?
+        };
 
         let linux = oci
             .linux
@@ -311,6 +314,17 @@ impl AgentService {
             return Err(anyhow!(nix::Error::EINVAL));
         };
 
+        #[cfg(feature = "sealed-secret")]
+        {
+            let client = self
+                .cdh_client
+                .as_ref()
+                .ok_or(anyhow!("get cdh_client failed"))?;
+            for source_path in sealed_source_path.iter_mut() {
+                client.unseal_file(source_path).await?;
+            }
+        }
+
         // if starting container failed, we will do some rollback work
         // to ensure no resources are leaked.
         if let Err(err) = ctr.start(p).await {

src/runtime/virtcontainers/kata_agent.go

@@ -911,6 +911,10 @@ func (k *kataAgent) replaceOCIMountSource(spec *specs.Spec, guestMounts map[stri
 	for index, m := range ociMounts {
 		if guestMount, ok := guestMounts[m.Destination]; ok {
 			k.Logger().Debugf("Replacing OCI mount (%s) source %s with %s", m.Destination, m.Source, guestMount.Source)
+                        if strings.Contains(m.Source, "kubernetes.io~secret") {
+                           ociMounts[index].Destination = "/sealed" + m.Destination
+                           k.Logger().Debugf("Replacing OCI mount (%s) with new destination %s", m.Destination, ociMounts[index].Destination)
+                        }
 			ociMounts[index].Source = guestMount.Source
 		}
 	}