fix(os): pass the decrypted env to app-compose without EnvironmentFile

docs/security/cvm-boundaries.md

@@ -126,7 +126,7 @@ dstack uses encrypted environment variables to allow app developers to securely
    - CVM decrypts the ciphertext using AESGCM with the derived shared secret
    - CVM parses the JSON and only stores variables listed in allowed_envs from app-compose.json
    - CVM performs basic regex validation on values
-   - Final result is stored as /dstack/.hostshared/.decrypted-env and loaded system-wide via app-compose.service
+   - Final result is stored as /dstack/.host-shared/.decrypted-env.json and passed to app-compose.service through `dstack-util exec-with-env`
 
 This file is not measured to RTMRs. But it is highly recommended to add application-specific integrity checks on encrypted environment variables at the application layer. See [security-best-practices.md](./security-best-practices.md) for more details.
 

dstack/dstack-util/src/main.rs

@@ -104,6 +104,18 @@ enum Commands {
     Encrypt(EncryptArgs),
     /// Sample NVIDIA GPU telemetry through NVML and print it as JSON
     GpuInfo,
+    /// Exec a command with extra environment variables from a JSON object file
+    ExecWithEnv(ExecWithEnvArgs),
+}
+
+#[derive(Parser)]
+struct ExecWithEnvArgs {
+    /// JSON object mapping variable names to values
+    #[arg(long)]
+    env_file: PathBuf,
+    /// Command to exec, with its arguments
+    #[arg(last = true, required = true)]
+    command: Vec<String>,
 }
 
 #[derive(Parser)]
@@ -721,6 +733,20 @@ async fn cmd_get_keys(args: GetKeysArgs) -> Result<()> {
     Ok(())
 }
 
+fn cmd_exec_with_env(args: ExecWithEnvArgs) -> Result<()> {
+    use std::os::unix::process::CommandExt;
+
+    let envs: std::collections::BTreeMap<String, String> =
+        utils::deserialize_json_file(&args.env_file)
+            .with_context(|| format!("failed to load env from {}", args.env_file.display()))?;
+    let (program, program_args) = args.command.split_first().context("no command given")?;
+    let err = std::process::Command::new(program)
+        .args(program_args)
+        .envs(envs)
+        .exec();
+    Err(err).with_context(|| format!("failed to exec {program}"))
+}
+
 fn cmd_decrypt(args: DecryptArgs) -> Result<()> {
     use dstack_types::shared_filenames::{host_shared_dir, APP_KEYS};
 
@@ -1667,6 +1693,7 @@ async fn main() -> Result<()> {
         Commands::GpuInfo => {
             gpu_info::cmd_gpu_info()?;
         }
+        Commands::ExecWithEnv(args) => cmd_exec_with_env(args)?,
     }
 
     Ok(())

os/common/rootfs/app-compose.service

@@ -9,10 +9,9 @@ OnFailure=dstack-boot-error@%n.service
 [Service]
 Type=oneshot
 RemainAfterExit=true
-EnvironmentFile=-/dstack/.host-shared/.decrypted-env
 WorkingDirectory=/dstack
-ExecStart=/bin/app-compose.sh
-ExecStop=/bin/app-compose.sh stop
+ExecStart=/bin/dstack-util exec-with-env --env-file /dstack/.host-shared/.decrypted-env.json -- /bin/app-compose.sh
+ExecStop=/bin/dstack-util exec-with-env --env-file /dstack/.host-shared/.decrypted-env.json -- /bin/app-compose.sh stop
 StandardOutput=journal+console
 StandardError=journal+console