fix(windows): avoid inadvertly running exes from cwd (starship#2885)

On Windows when running commands with their name instead of the path with Command::new, executable with that name from the current working directory will be executed.

This PR replaces all instances of Command::new with a new create_command function which will first resolve any executable paths and avoid this issue.

CONTRIBUTING.md

@@ -68,6 +68,8 @@ pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
 }
 ```
 
+If using `context.exec_cmd` isn't possible, please use `crate::utils::create_command` instead of `std::process::Command::new`.
+
 ## Logging
 
 Debug logging in starship is done with our custom logger implementation.

clippy.toml

@@ -0,0 +1,2 @@
+# std::process::Command::new may inadvertly run executables from the current working directory
+disallowed-methods = ["std::process::Command::new"]

src/bug_report.rs

@@ -265,18 +265,6 @@ mod tests {
         assert!(link.contains("No+Starship+config"));
     }
 
-    #[test]
-    fn test_get_shell_info() {
-        env::remove_var("STARSHIP_SHELL");
-        let unknown_shell = get_shell_info();
-        assert_eq!(UNKNOWN_SHELL, &unknown_shell.name);
-
-        env::set_var("STARSHIP_SHELL", "fish");
-
-        let fish_shell = get_shell_info();
-        assert_eq!("fish", &fish_shell.name);
-    }
-
     #[test]
     #[cfg(not(windows))]
     fn test_get_config_path() {

src/configure.rs

@@ -2,7 +2,6 @@ use std::env;
 use std::ffi::OsString;
 use std::io::ErrorKind;
 use std::process;
-use std::process::Command;
 
 use crate::config::RootModuleConfig;
 use crate::config::StarshipConfig;
@@ -136,9 +135,9 @@ pub fn write_configuration(table: &mut Table) {
 pub fn edit_configuration() {
     let config_path = get_config_path();
     let editor_cmd = shell_words::split(&get_editor()).expect("Unmatched quotes found in $EDITOR.");
-    let editor_path = which::which(&editor_cmd[0]).expect("Unable to locate editor in $PATH.");
 
-    let command = Command::new(editor_path)
+    let command = utils::create_command(&editor_cmd[0])
+        .expect("Unable to locate editor in $PATH.")
         .args(&editor_cmd[1..])
         .arg(config_path)
         .status();

src/init/mod.rs

@@ -1,3 +1,4 @@
+use crate::utils::create_command;
 use std::ffi::OsStr;
 use std::path::{Path, PathBuf};
 use std::{env, io};
@@ -51,9 +52,7 @@ impl StarshipPath {
             return self.sprint();
         }
         let str_path = self.str_path()?;
-        let res = std::process::Command::new("cygpath.exe")
-            .arg(str_path)
-            .output();
+        let res = create_command("cygpath").and_then(|mut cmd| cmd.arg(str_path).output());
         let output = match res {
             Ok(output) => output,
             Err(e) => {

src/lib.rs

@@ -1,3 +1,5 @@
+#![warn(clippy::disallowed_method)]
+
 #[macro_use]
 extern crate shadow_rs;
 

src/main.rs

@@ -1,3 +1,5 @@
+#![warn(clippy::disallowed_method)]
+
 use clap::crate_authors;
 use std::io;
 use std::time::SystemTime;

src/modules/custom.rs

@@ -5,7 +5,7 @@ use std::time::Instant;
 
 use super::{Context, Module, RootModuleConfig};
 
-use crate::{configs::custom::CustomConfig, formatter::StringFormatter};
+use crate::{configs::custom::CustomConfig, formatter::StringFormatter, utils::create_command};
 
 /// Creates a custom module with some configuration
 ///
@@ -100,7 +100,7 @@ fn get_shell<'a, 'b>(shell_args: &'b [&'a str]) -> (std::borrow::Cow<'a, str>, &
 #[cfg(not(windows))]
 fn shell_command(cmd: &str, shell_args: &[&str]) -> Option<Output> {
     let (shell, shell_args) = get_shell(shell_args);
-    let mut command = Command::new(shell.as_ref());
+    let mut command = create_command(shell.as_ref()).ok()?;
 
     command
         .args(shell_args)
@@ -118,6 +118,7 @@ fn shell_command(cmd: &str, shell_args: &[&str]) -> Option<Output> {
                 "Could not launch command with given shell or STARSHIP_SHELL env variable, retrying with /usr/bin/env sh"
             );
 
+            #[allow(clippy::disallowed_method)]
             Command::new("/usr/bin/env")
                 .arg("sh")
                 .stdin(Stdio::piped())
@@ -141,14 +142,17 @@ fn shell_command(cmd: &str, shell_args: &[&str]) -> Option<Output> {
             Some(std::borrow::Cow::Borrowed(shell_args[0])),
             &shell_args[1..],
         )
-    } else if let Ok(env_shell) = std::env::var("STARSHIP_SHELL") {
+    } else if let Some(env_shell) = std::env::var("STARSHIP_SHELL")
+        .ok()
+        .filter(|s| !cfg!(test) && !s.is_empty())
+    {
         (Some(std::borrow::Cow::Owned(env_shell)), &[] as &[&str])
     } else {
         (None, &[] as &[&str])
     };
 
     if let Some(forced_shell) = shell {
-        let mut command = Command::new(forced_shell.as_ref());
+        let mut command = create_command(forced_shell.as_ref()).ok()?;
 
         command
             .args(shell_args)
@@ -169,7 +173,8 @@ fn shell_command(cmd: &str, shell_args: &[&str]) -> Option<Output> {
         );
     }
 
-    let command = Command::new("cmd.exe")
+    let command = create_command("cmd")
+        .ok()?
         .arg("/C")
         .arg(cmd)
         .stdin(Stdio::piped())

src/modules/directory.rs

@@ -298,14 +298,14 @@ fn to_fish_style(pwd_dir_length: usize, dir_string: String, truncated_dir_string
 mod tests {
     use super::*;
     use crate::test::ModuleRenderer;
+    use crate::utils::create_command;
     use crate::utils::home_dir;
     use ansi_term::Color;
     #[cfg(not(target_os = "windows"))]
     use std::os::unix::fs::symlink;
     #[cfg(target_os = "windows")]
     use std::os::windows::fs::symlink_dir as symlink;
     use std::path::Path;
-    use std::process::Command;
     use std::{fs, io};
     use tempfile::TempDir;
 
@@ -443,7 +443,7 @@ mod tests {
     }
 
     fn init_repo(path: &Path) -> io::Result<()> {
-        Command::new("git")
+        create_command("git")?
             .args(&["init"])
             .current_dir(path)
             .output()

src/modules/dotnet.rs

@@ -345,10 +345,10 @@ enum FileType {
 mod tests {
     use super::*;
     use crate::test::ModuleRenderer;
+    use crate::utils::create_command;
     use ansi_term::Color;
     use std::fs::{self, OpenOptions};
     use std::io::{self, Write};
-    use std::process::Command;
     use tempfile::{self, TempDir};
 
     #[test]
@@ -551,7 +551,7 @@ mod tests {
         let repo_dir = tempfile::tempdir()?;
 
         if is_repo {
-            Command::new("git")
+            create_command("git")?
                 .args(&["init", "--quiet"])
                 .current_dir(repo_dir.path())
                 .output()?;

src/modules/git_branch.rs

@@ -121,9 +121,9 @@ fn get_first_grapheme(text: &str) -> &str {
 mod tests {
     use ansi_term::Color;
     use std::io;
-    use std::process::Command;
 
     use crate::test::{fixture_repo, FixtureProvider, ModuleRenderer};
+    use crate::utils::create_command;
 
     #[test]
     fn show_nothing_on_empty_dir() -> io::Result<()> {
@@ -270,12 +270,12 @@ mod tests {
     fn test_works_with_unborn_default_branch() -> io::Result<()> {
         let repo_dir = tempfile::tempdir()?;
 
-        Command::new("git")
+        create_command("git")?
             .args(&["init"])
             .current_dir(&repo_dir)
             .output()?;
 
-        Command::new("git")
+        create_command("git")?
             .args(&["symbolic-ref", "HEAD", "refs/heads/main"])
             .current_dir(&repo_dir)
             .output()?;
@@ -297,7 +297,7 @@ mod tests {
     fn test_render_branch_only_attached_on_branch() -> io::Result<()> {
         let repo_dir = fixture_repo(FixtureProvider::Git)?;
 
-        Command::new("git")
+        create_command("git")?
             .args(&["checkout", "-b", "test_branch"])
             .current_dir(repo_dir.path())
             .output()?;
@@ -325,7 +325,7 @@ mod tests {
     fn test_render_branch_only_attached_on_detached() -> io::Result<()> {
         let repo_dir = fixture_repo(FixtureProvider::Git)?;
 
-        Command::new("git")
+        create_command("git")?
             .args(&["checkout", "@~1"])
             .current_dir(&repo_dir.path())
             .output()?;
@@ -348,12 +348,12 @@ mod tests {
     fn test_works_in_bare_repo() -> io::Result<()> {
         let repo_dir = tempfile::tempdir()?;
 
-        Command::new("git")
+        create_command("git")?
             .args(&["init", "--bare"])
             .current_dir(&repo_dir)
             .output()?;
 
-        Command::new("git")
+        create_command("git")?
             .args(&["symbolic-ref", "HEAD", "refs/heads/main"])
             .current_dir(&repo_dir)
             .output()?;
@@ -379,7 +379,7 @@ mod tests {
     // fn test_git_dir_env_variable() -> io::Result<()> {let repo_dir =
     // tempfile::tempdir()?;
 
-    //     Command::new("git")
+    //     create_command("git")?
     //         .args(&["init"])
     //         .current_dir(&repo_dir)
     //         .output()?;
@@ -424,7 +424,7 @@ mod tests {
     ) -> io::Result<()> {
         let repo_dir = fixture_repo(FixtureProvider::Git)?;
 
-        Command::new("git")
+        create_command("git")?
             .args(&["checkout", "-b", branch_name])
             .current_dir(repo_dir.path())
             .output()?;
@@ -463,7 +463,7 @@ mod tests {
     ) -> io::Result<()> {
         let repo_dir = fixture_repo(FixtureProvider::Git)?;
 
-        Command::new("git")
+        create_command("git")?
             .args(&["checkout", "-b", branch_name])
             .current_dir(repo_dir.path())
             .output()?;

src/modules/git_commit.rs

@@ -105,10 +105,10 @@ fn id_to_hex_abbrev(bytes: &[u8], len: usize) -> String {
 #[cfg(test)]
 mod tests {
     use ansi_term::Color;
-    use std::process::Command;
     use std::{io, str};
 
     use crate::test::{fixture_repo, FixtureProvider, ModuleRenderer};
+    use crate::utils::create_command;
 
     #[test]
     fn show_nothing_on_empty_dir() -> io::Result<()> {
@@ -128,7 +128,7 @@ mod tests {
     fn test_render_commit_hash() -> io::Result<()> {
         let repo_dir = fixture_repo(FixtureProvider::Git)?;
 
-        let mut git_output = Command::new("git")
+        let mut git_output = create_command("git")?
             .args(&["rev-parse", "HEAD"])
             .current_dir(&repo_dir.path())
             .output()?
@@ -160,7 +160,7 @@ mod tests {
     fn test_render_commit_hash_len_override() -> io::Result<()> {
         let repo_dir = fixture_repo(FixtureProvider::Git)?;
 
-        let mut git_output = Command::new("git")
+        let mut git_output = create_command("git")?
             .args(&["rev-parse", "HEAD"])
             .current_dir(&repo_dir.path())
             .output()?
@@ -207,12 +207,12 @@ mod tests {
     fn test_render_commit_hash_only_detached_on_detached() -> io::Result<()> {
         let repo_dir = fixture_repo(FixtureProvider::Git)?;
 
-        Command::new("git")
+        create_command("git")?
             .args(&["checkout", "@~1"])
             .current_dir(&repo_dir.path())
             .output()?;
 
-        let mut git_output = Command::new("git")
+        let mut git_output = create_command("git")?
             .args(&["rev-parse", "HEAD"])
             .current_dir(&repo_dir.path())
             .output()?
@@ -240,15 +240,15 @@ mod tests {
     fn test_render_commit_hash_with_tag_enabled() -> io::Result<()> {
         let repo_dir = fixture_repo(FixtureProvider::Git)?;
 
-        let mut git_commit = Command::new("git")
+        let mut git_commit = create_command("git")?
             .args(&["rev-parse", "HEAD"])
             .current_dir(&repo_dir.path())
             .output()?
             .stdout;
         git_commit.truncate(7);
         let commit_output = str::from_utf8(&git_commit).unwrap().trim();
 
-        let git_tag = Command::new("git")
+        let git_tag = create_command("git")?
             .args(&["describe", "--tags", "--exact-match", "HEAD"])
             .current_dir(&repo_dir.path())
             .output()?
@@ -283,25 +283,25 @@ mod tests {
     fn test_render_commit_hash_only_detached_on_detached_with_tag_enabled() -> io::Result<()> {
         let repo_dir = fixture_repo(FixtureProvider::Git)?;
 
-        Command::new("git")
+        create_command("git")?
             .args(&["checkout", "@~1"])
             .current_dir(&repo_dir.path())
             .output()?;
 
-        Command::new("git")
+        create_command("git")?
             .args(&["tag", "tagOnDetached", "-m", "Testing tags on detached"])
             .current_dir(&repo_dir.path())
             .output()?;
 
-        let mut git_commit = Command::new("git")
+        let mut git_commit = create_command("git")?
             .args(&["rev-parse", "HEAD"])
             .current_dir(&repo_dir.path())
             .output()?
             .stdout;
         git_commit.truncate(7);
         let commit_output = str::from_utf8(&git_commit).unwrap().trim();
 
-        let git_tag = Command::new("git")
+        let git_tag = create_command("git")?
             .args(&["describe", "--tags", "--exact-match", "HEAD"])
             .current_dir(&repo_dir.path())
             .output()?
@@ -337,33 +337,33 @@ mod tests {
 
         let repo_dir = fixture_repo(FixtureProvider::Git)?;
 
-        let mut git_commit = Command::new("git")
+        let mut git_commit = create_command("git")?
             .args(&["rev-parse", "HEAD"])
             .current_dir(&repo_dir.path())
             .output()?
             .stdout;
         git_commit.truncate(7);
         let commit_output = str::from_utf8(&git_commit).unwrap().trim();
 
-        Command::new("git")
+        create_command("git")?
             .args(&["tag", "v2", "-m", "Testing tags v2"])
             .current_dir(&repo_dir.path())
             .output()?;
 
         // Wait one second between tags
         thread::sleep(time::Duration::from_millis(1000));
 
-        Command::new("git")
+        create_command("git")?
             .args(&["tag", "v0", "-m", "Testing tags v0", "HEAD~1"])
             .current_dir(&repo_dir.path())
             .output()?;
 
-        Command::new("git")
+        create_command("git")?
             .args(&["tag", "v1", "-m", "Testing tags v1"])
             .current_dir(&repo_dir.path())
             .output()?;
 
-        let git_tag = Command::new("git")
+        let git_tag = create_command("git")?
             .args(&[
                 "for-each-ref",
                 "--contains",