path resolution (hopefully without path traversal!)

Signed-off-by: metamuffin <metamuffin@disroot.org>

2 files changed, 17 insertions, 3 deletions

diff --git a/src/error.rs b/src/error.rs
index 59f4443..83a1ffa 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -18,6 +18,8 @@ pub enum ServiceError {
     BadRange,
     #[error("bad utf8")]
     BadUtf8(#[from] std::str::Utf8Error),
+    #[error("bad path")]
+    BadPath,
     #[error("ohh. i didn't expect that this error can be generated.")]
     Other,
 }
diff --git a/src/files.rs b/src/files.rs
index 2ba9a9f..68a3807 100644
--- a/src/files.rs
+++ b/src/files.rs
@@ -27,12 +27,24 @@ pub async fn serve_files(
     let rpath = req.uri().path();
 
     let mut path = config.root.clone();
+    let mut user_path_depth = 0;
     for seg in rpath.split("/") {
         let seg = percent_decode_str(seg).decode_utf8()?;
-        if seg == "" || seg == ".." {
-            continue; // not ideal
+
+        if seg == "" || seg == "." {
+            continue;
+        }
+
+        if seg == ".." {
+            if user_path_depth <= 0 {
+                return Err(ServiceError::BadPath);
+            }
+            path.pop();
+            user_path_depth -= 1;
+        } else {
+            path.push(seg.as_ref());
+            user_path_depth += 1;
         }
-        path.push(seg.as_ref())
     }
     if !path.exists() {
         return Err(ServiceError::NotFound);