ssh: Fix shell escaping

The previous `sh -c` invocation was incorrect and just happened
to work on hosts with a Bourne-compatible shell set as the login
shell. Commands in the deploy script were being executed in the
login shell.

Cargo.lock

@@ -131,6 +131,7 @@ dependencies = [
  "regex",
  "serde",
  "serde_json",
+ "shell-escape",
  "snafu",
  "sys-info",
  "tempfile",
@@ -680,6 +681,12 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "shell-escape"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "45bb67a18fa91266cc7807181f62f9178a6873bfad7dc788c42e6430db40184f"
+
 [[package]]
 name = "signal-hook-registry"
 version = "1.2.2"

Cargo.toml

@@ -22,6 +22,7 @@ quit = "1.1.2"
 regex = "1"
 serde = { version = "1.0.118", features = ["derive"] }
 serde_json = "1.0"
+shell-escape = "0.1.5"
 sys-info = "0.7.0"
 snafu = "0.6.10"
 tempfile = "3.1.0"

default.nix

@@ -14,7 +14,7 @@ in rustPlatform.buildRustPackage {
       src = ./.;
     };
   };
-  cargoSha256 = "0rkpv9afkg33i1d0yjlq34zrdqy3i6ldbdag0hgsvxi3v3jfg4qv";
+  cargoSha256 = "1yjaqhv9gd86jq56vsrhv6qv3k5qh2pnc4zyxbi2fm2hdrvy0440";
 
   # Recursive Nix is not stable yet
   doCheck = false;

src/nix/host/ssh.rs

@@ -5,6 +5,7 @@ use std::process::Stdio;
 
 use async_trait::async_trait;
 use futures::future::join3;
+use shell_escape::unix::escape;
 use tokio::process::Command;
 use tokio::io::{AsyncWriteExt, BufReader};
 
@@ -199,13 +200,14 @@ impl Ssh {
 
         let dest_path = key.dest_dir().join(name);
 
-        let remote_command = DEPLOY_KEY_TEMPLATE.to_string()
+        let key_script = DEPLOY_KEY_TEMPLATE.to_string()
             .replace("%DESTINATION%", dest_path.to_str().unwrap())
-            .replace("%USER%", &key.user())
-            .replace("%GROUP%", &key.group())
-            .replace("%PERMISSIONS%", &key.permissions());
+            .replace("%USER%", &escape(key.user().into()))
+            .replace("%GROUP%", &escape(key.group().into()))
+            .replace("%PERMISSIONS%", &escape(key.permissions().into()));
+        let key_script = escape(key_script.into());
 
-        let mut command = self.ssh(&["sh", "-c", &remote_command]);
+        let mut command = self.ssh(&["sh", "-c", &key_script]);
 
         command.stdin(Stdio::piped());
         command.stderr(Stdio::piped());