node: Run git fetch without any user config

radicle-node/src/runtime.rs

@@ -235,6 +235,7 @@ pub mod daemon {
         let child = Command::new("git")
             .env_clear()
             .envs(env::vars().filter(|(k, _)| k == "PATH" || k.starts_with("GIT")))
+            .envs(radicle::git::env::GIT_RESET)
             .env("GIT_PROTOCOL", "version=2")
             .current_dir(storage)
             .arg("daemon")

radicle-node/src/worker.rs

@@ -153,6 +153,7 @@ impl<G: Signer + EcSign + 'static> Worker<G> {
         cmd.current_dir(repo.path())
             .env_clear()
             .envs(env::vars().filter(|(k, _)| k == "PATH" || k.starts_with("GIT_TRACE")))
+            .envs(git::env::GIT_RESET)
             .args(["-c", "protocol.version=2"])
             .arg("fetch")
             .arg("--verbose");

radicle/src/git.rs

@@ -507,6 +507,16 @@ pub mod url {
     }
 }
 
+/// Git environment variables.
+pub mod env {
+    /// Set of environment vars to reset git's configuration to default.
+    pub const GIT_RESET: [(&str, &str); 3] = [
+        ("GIT_CONFIG", "/dev/null"),
+        ("GIT_CONFIG_GLOBAL", "/dev/null"),
+        ("GIT_CONFIG_NOSYSTEM", "1"),
+    ];
+}
+
 #[cfg(test)]
 mod test {
     use super::*;