Pass SSH public keys through to cloud-init (#974)

nexus/src/cidata.rs

@@ -9,12 +9,15 @@ use uuid::Uuid;
 pub const MAX_USER_DATA_BYTES: usize = 32 * 1024; // 32 KiB
 
 impl Instance {
-    pub fn generate_cidata(&self) -> Result<Vec<u8>, Error> {
+    pub fn generate_cidata(
+        &self,
+        public_keys: &[String],
+    ) -> Result<Vec<u8>, Error> {
         // cloud-init meta-data is YAML, but YAML is a strict superset of JSON.
         let meta_data = serde_json::to_vec(&MetaData {
             instance_id: self.id(),
             local_hostname: &self.runtime().hostname,
-            public_keys: &[], // TODO
+            public_keys,
         })
         .map_err(|_| Error::internal_error("failed to serialize meta-data"))?;
         let cidata =
@@ -67,10 +70,10 @@ fn build_vfat(meta_data: &[u8], user_data: &[u8]) -> io::Result<Vec<u8>> {
         let root_dir = fs.root_dir();
         for (file, data) in [("meta-data", meta_data), ("user-data", user_data)]
         {
-            if !data.is_empty() {
-                let mut file = root_dir.create_file(file)?;
-                file.write_all(data)?;
-            }
+            // Cloud-init requires the files `meta-data` and `user-data`
+            // to be present, even if empty.
+            let mut file = root_dir.create_file(file)?;
+            file.write_all(data)?;
         }
     }
 

nexus/src/nexus.rs

@@ -124,6 +124,8 @@ pub(crate) const MAX_DISKS_PER_INSTANCE: u32 = 8;
 
 pub(crate) const MAX_NICS_PER_INSTANCE: u32 = 8;
 
+pub(crate) const MAX_KEYS_PER_INSTANCE: u32 = 8;
+
 /// Manages an Oxide fleet -- the heart of the control plane
 pub struct Nexus {
     /// uuid for this nexus instance.
@@ -1852,6 +1854,32 @@ impl Nexus {
             .derive_guest_network_interface_info(&opctx, &authz_instance)
             .await?;
 
+        // Gather the SSH public keys of the actor make the request so
+        // that they may be injected into the new image via cloud-init.
+        // TODO-security: this should be replaced with a lookup based on
+        // on `SiloUser` role assignments once those are in place.
+        let actor = opctx.authn.actor_required()?;
+        let (.., authz_user) = LookupPath::new(opctx, &self.db_datastore)
+            .silo_user_id(actor.actor_id())
+            .lookup_for(authz::Action::ListChildren)
+            .await?;
+        let public_keys = self
+            .db_datastore
+            .ssh_keys_list(
+                opctx,
+                &authz_user,
+                &DataPageParams {
+                    marker: None,
+                    direction: dropshot::PaginationOrder::Ascending,
+                    limit: std::num::NonZeroU32::new(MAX_KEYS_PER_INSTANCE)
+                        .unwrap(),
+                },
+            )
+            .await?
+            .into_iter()
+            .map(|ssh_key| ssh_key.public_key)
+            .collect::<Vec<String>>();
+
         // Ask the sled agent to begin the state change.  Then update the
         // database to reflect the new intermediate state.  If this update is
         // not the newest one, that's fine.  That might just mean the sled agent
@@ -1864,7 +1892,7 @@ impl Nexus {
             nics,
             disks: disk_reqs,
             cloud_init_bytes: Some(base64::encode(
-                db_instance.generate_cidata()?,
+                db_instance.generate_cidata(&public_keys)?,
             )),
         };