From cb78527176c2c13cf6123304bcb96459414f4244 Mon Sep 17 00:00:00 2001
From: Susanne Westphal <swestphal@google.com>
Date: Wed, 18 Dec 2024 13:21:27 +0000
Subject: [PATCH] Add empty action for execute signed command

---
 crates/rrg/Cargo.toml                         |   2 +
 crates/rrg/src/action.rs                      |   7 ++
 .../rrg/src/action/execute_signed_command.rs  | 115 ++++++++++++++++++
 proto/rrg.proto                               |   2 +
 4 files changed, 126 insertions(+)
 create mode 100644 crates/rrg/src/action/execute_signed_command.rs

diff --git a/crates/rrg/Cargo.toml b/crates/rrg/Cargo.toml
index 5de54742..c0e4c582 100644
--- a/crates/rrg/Cargo.toml
+++ b/crates/rrg/Cargo.toml
@@ -22,6 +22,7 @@ default = [
     "action-list_winreg_values",
     "action-list_winreg_keys",
     "action-query_wmi",
+    "action-execute_signed_command",
 ]
 
 action-get_system_metadata = []
@@ -39,6 +40,7 @@ action-get_winreg_value = []
 action-list_winreg_values = []
 action-list_winreg_keys = []
 action-query_wmi = []
+action-execute_signed_command = []
 
 test-setfattr = []
 test-chattr = []
diff --git a/crates/rrg/src/action.rs b/crates/rrg/src/action.rs
index 23db0798..16e0fd95 100644
--- a/crates/rrg/src/action.rs
+++ b/crates/rrg/src/action.rs
@@ -51,6 +51,9 @@ pub mod list_winreg_keys;
 #[cfg(feature = "action-query_wmi")]
 pub mod query_wmi;
 
+#[cfg(feature = "action-execute_signed_command")]
+pub mod execute_signed_command;
+
 use log::info;
 
 /// Dispatches the given `request` to an appropriate action handler.
@@ -125,6 +128,10 @@ where
         QueryWmi => {
             handle(session, request, self::query_wmi::handle)
         }
+        #[cfg(feature = "action-execute_signed_command")]
+        ExecuteSignedCommand => {
+            handle(session, request, self::execute_signed_command::handle)
+        }
         // We allow `unreachable_patterns` because otherwise we get a warning if
         // we compile with all the actions enabled.
         #[allow(unreachable_patterns)]
diff --git a/crates/rrg/src/action/execute_signed_command.rs b/crates/rrg/src/action/execute_signed_command.rs
new file mode 100644
index 00000000..37bcd0e7
--- /dev/null
+++ b/crates/rrg/src/action/execute_signed_command.rs
@@ -0,0 +1,115 @@
+// Copyright 2024 Google LLC
+//
+// Use of this source code is governed by an MIT-style license that can be found
+// in the LICENSE file or at https://opensource.org/licenses/MIT.
+
+use std::{io::{Read, Write}, os::unix::process::ExitStatusExt, process::{Command, ExitStatus}};
+
+use protobuf::Message;
+
+/// Arguments of the `execute_signed_command` action.
+pub struct Args {
+    raw_command: Vec<u8>,
+    command: rrg_proto::execute_signed_command::SignedCommand,
+    stdin: Stdin,
+    ed25519_signature: ed25519_dalek::Signature,
+    timeout: std::time::Duration,
+}
+
+/// Result of the `execute_signed_command` action.
+pub struct Item {
+    /// Exit status of the command subprocess.
+    exit_status: ExitStatus,
+    /// Standard output of the command executiom.
+    stdout: Vec<u8>,
+    /// Wheather standard output is truncated.
+    truncated_stdout: bool,
+    /// Standard error of the command executiom.
+    stderr: Vec<u8>,
+    /// Wheather stderr is truncated.
+    truncated_stderr: bool,
+}
+
+enum Stdin {
+    NONE,
+    UNSIGNED(Vec<u8>),
+    SIGNED(Vec<u8>),
+}
+
+
+/// Handles invocations of the `execute_signed_command` action.
+pub fn handle<S>(session: &mut S, mut args: Args) -> crate::session::Result<()>
+where
+    S: crate::session::Session,
+{
+    // TODO(s-westphal): Add implementation.
+    Ok(())
+}
+
+impl crate::request::Args for Args {
+
+    type Proto = rrg_proto::execute_signed_command::Args;
+
+    fn from_proto(mut proto: Self::Proto) -> Result<Args, crate::request::ParseArgsError> {
+        use crate::request::ParseArgsError;
+
+        let raw_signature= proto.take_command_ed25519_signature();
+
+        let ed25519_signature = ed25519_dalek::Signature::try_from(&raw_signature[..])
+            .map_err(|error| ParseArgsError::invalid_field("command_ed25519_signature", error))?;
+
+        let raw_command = proto.take_command();
+        let mut command = rrg_proto::execute_signed_command::SignedCommand::parse_from_bytes(&raw_command)
+            .map_err(|error| ParseArgsError::invalid_field("command", error))?;
+
+
+        let stdin: Stdin;
+        if command.has_signed_stdin() {
+            stdin = Stdin::SIGNED(command.take_signed_stdin());
+        } else if command.unsigned_stdin() && !proto.unsigned_stdin.is_empty() {
+            stdin = Stdin::UNSIGNED(proto.take_unsigned_stdin());
+        } else {
+            stdin = Stdin::NONE
+        }
+
+        let timeout = std::time::Duration::try_from(proto.take_timeout())
+            .map_err(|error| ParseArgsError::invalid_field("command", error))?;
+
+        Ok(Args {
+            raw_command,
+            command,
+            ed25519_signature,
+            stdin,
+            timeout,
+        })
+    }
+}
+
+impl crate::response::Item for Item {
+
+    type Proto = rrg_proto::execute_signed_command::Result;
+
+    fn into_proto(self) -> Self::Proto {
+
+        let mut proto = rrg_proto::execute_signed_command::Result::new();
+
+        if let Some(exit_code) = self.exit_status.code() {
+            proto.set_exit_code(exit_code);
+        }
+
+        #[cfg(target_family = "unix")]
+        {
+            if let Some(exit_signal) = self.exit_status.signal() {
+                proto.set_exit_signal(exit_signal);
+            }
+        }
+
+        proto.set_stdout(self.stdout);
+        proto.set_stdout_truncated(self.truncated_stdout);
+
+        proto.set_stderr(self.stderr);
+        proto.set_stderr_truncated(self.truncated_stderr);
+
+        proto
+    }
+}
\ No newline at end of file
diff --git a/proto/rrg.proto b/proto/rrg.proto
index ded2ffde..4f40993f 100644
--- a/proto/rrg.proto
+++ b/proto/rrg.proto
@@ -48,6 +48,8 @@ enum Action {
   QUERY_WMI = 16;
   /// Grep the specified file for a pattern.
   GREP_FILE_CONTENTS = 17;
+  /// Execute a signed command.
+  EXECUTE_SIGNED_COMMAND = 18;
 
   // TODO: Define more actions that should be supported.