add PathBuf resolved validation

src/preload.rs

@@ -3,7 +3,7 @@ use std::{fs, path::PathBuf};
 
 /// Temporary file storage for `librqbit` preload data
 pub struct Preload {
-    directory: PathBuf,
+    root: PathBuf,
     pub max_filecount: Option<usize>,
     pub max_filesize: Option<u64>,
 }
@@ -20,21 +20,17 @@ impl Preload {
         Ok(Self {
             max_filecount,
             max_filesize,
-            directory,
+            root: directory.canonicalize()?,
         })
     }
 
     pub fn clear_output_folder(&self, info_hash: &str) -> Result<()> {
-        let mut p = PathBuf::from(&self.directory);
-        p.push(info_hash);
-        fs::remove_dir_all(&p)?;
-        Ok(())
+        Ok(fs::remove_dir_all(&self.path(&PathBuf::from(info_hash))?)?)
     }
 
     /// * create new directory if not exists
     pub fn output_folder(&self, info_hash: &str) -> Result<PathBuf> {
-        let mut p = PathBuf::from(&self.directory);
-        p.push(info_hash);
+        let p = self.path(&PathBuf::from(info_hash))?;
         if !p.exists() {
             fs::create_dir(&p)?
         }
@@ -42,14 +38,22 @@ impl Preload {
     }
 
     pub fn root(&self) -> PathBuf {
-        self.directory.clone()
+        self.root.clone()
     }
 
-    pub fn bytes(&self, path: &PathBuf) -> Result<Vec<u8>> {
-        Ok(std::fs::read({
-            let mut p = PathBuf::from(&self.directory);
-            p.push(path);
-            p
-        })?)
+    pub fn bytes(&self, relative: &PathBuf) -> Result<Vec<u8>> {
+        Ok(std::fs::read(self.path(relative)?)?)
+    }
+
+    fn path(&self, relative: &PathBuf) -> Result<PathBuf> {
+        let mut p = PathBuf::from(&self.root);
+        p.push(relative);
+        if p.canonicalize()?.starts_with(&self.root) {
+            bail!(
+                "Unexpected absolute path resolved for `{}`!",
+                p.to_string_lossy()
+            )
+        }
+        Ok(p)
     }
 }