From 9e0363c7f908ab0434e2c7b164b5f75639af18bd Mon Sep 17 00:00:00 2001
From: Aymeric <198801145+grappig@users.noreply.github.com>
Date: Thu, 1 Oct 2026 14:11:39 +0200
Subject: [PATCH 1/2] add proc mount point scaffold

---
 src/rootfs.rs | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/src/rootfs.rs b/src/rootfs.rs
index 7cf3fc4..54e2f1a 100644
--- a/src/rootfs.rs
+++ b/src/rootfs.rs
@@ -44,6 +44,22 @@ pub fn inspect(path: &Path) -> io::Result<Inspection> {
     })
 }
 
+pub fn proc_mount_point(path: &Path) -> io::Result<std::path::PathBuf> {
+    let mount_point = path.join("proc");
+
+    if mount_point.is_dir() {
+        return Ok(mount_point);
+    }
+
+    Err(io::Error::new(
+        io::ErrorKind::NotFound,
+        format!(
+            "rootfs proc directory does not exist: {}",
+            mount_point.display()
+        ),
+    ))
+}
+
 #[cfg(test)]
 mod tests {
     use super::{DIRECTORIES, initialize, inspect};
@@ -107,4 +123,16 @@ mod tests {
 
         assert!(inspect(&directory.0).is_err());
     }
+
+    #[test]
+    fn returns_the_proc_directory_as_a_mount_point() {
+        let directory = TestDirectory::new("test-rootfs-proc");
+
+        initialize(&directory.0).unwrap();
+
+        assert_eq!(
+            super::proc_mount_point(&directory.0).unwrap(),
+            directory.0.join("proc")
+        );
+    }
 }

From d7d23d27fecf319cf4a5e52cdf1462361fbf2ee1 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 1 Oct 2026 12:17:02 +0000
Subject: [PATCH 2/2] Reject symlinked proc mount points

Co-authored-by: grappig <198801145+grappig@users.noreply.github.com>
---
 src/rootfs.rs | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/src/rootfs.rs b/src/rootfs.rs
index 54e2f1a..e680ef7 100644
--- a/src/rootfs.rs
+++ b/src/rootfs.rs
@@ -47,7 +47,7 @@ pub fn inspect(path: &Path) -> io::Result<Inspection> {
 pub fn proc_mount_point(path: &Path) -> io::Result<std::path::PathBuf> {
     let mount_point = path.join("proc");
 
-    if mount_point.is_dir() {
+    if fs::symlink_metadata(&mount_point).is_ok_and(|metadata| metadata.file_type().is_dir()) {
         return Ok(mount_point);
     }
 
@@ -62,7 +62,7 @@ pub fn proc_mount_point(path: &Path) -> io::Result<std::path::PathBuf> {
 
 #[cfg(test)]
 mod tests {
-    use super::{DIRECTORIES, initialize, inspect};
+    use super::{DIRECTORIES, initialize, inspect, proc_mount_point};
     use std::{
         fs,
         path::{Path, PathBuf},
@@ -131,8 +131,25 @@ mod tests {
         initialize(&directory.0).unwrap();
 
         assert_eq!(
-            super::proc_mount_point(&directory.0).unwrap(),
+            proc_mount_point(&directory.0).unwrap(),
             directory.0.join("proc")
         );
     }
+
+    #[cfg(unix)]
+    #[test]
+    fn rejects_a_symlinked_proc_mount_point() {
+        use std::os::unix::fs::symlink;
+
+        let directory = TestDirectory::new("test-rootfs-proc-symlink");
+        let rootfs = directory.0.join("rootfs");
+        let outside = directory.0.join("outside");
+
+        initialize(&rootfs).unwrap();
+        fs::create_dir_all(&outside).unwrap();
+        fs::remove_dir(rootfs.join("proc")).unwrap();
+        symlink(&outside, rootfs.join("proc")).unwrap();
+
+        assert!(proc_mount_point(&rootfs).is_err());
+    }
 }