CVE-2022-46171: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') (CWE-22)
value: Tauri is a framework for building binaries for all major desktop platforms. The filesystem glob pattern wildcards `*`, `?`, and `[...]` match file path literals and leading dots by default, which unintentionally exposes sub folder content of allowed paths. Scopes without the wildcards are not affected. As `**` allows for sub directories the behavior there is also as expected. The issue has been patched in the latest release and was backported into the currently supported 1.x branches. There are no known workarounds at the time of publication.
CWE description: The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
CVSS v3 base score: 7.7
Published: 2022-12-23T14:15Z
Repository: https://github.com/tauri-apps/tauri
Language: Rust
Files changed: .changes/glob-match-require_literal_separator.md, core/tauri/src/scope/fs.rs
Commit date: 2022-12-22 15:53:46 +0200
Commit message: Merge pull request from GHSA-6mv3-wm7j-h4w5

* fix(core): use `require_literal_separator` when matching paths

* document the need for `require_literal_separator`

* use `require_literal_leading_dot`
Diff: diff --git a/.changes/glob-match-require_literal_separator.md b/.changes/glob-match-require_literal_separator.md
new file mode 100644
index 00000000..482a8102
--- /dev/null
+++ b/.changes/glob-match-require_literal_separator.md
@@ -0,0 +1,5 @@
+---
+"tauri": "patch"
+---
+
+Fix the filesystem scope allowing sub-directories of the directory picked by the dialog when `recursive` option was `false`.
diff --git a/core/tauri/src/scope/fs.rs b/core/tauri/src/scope/fs.rs
index 32d92652..8979eb8f 100644
--- a/core/tauri/src/scope/fs.rs
+++ b/core/tauri/src/scope/fs.rs
@@ -139,11 +139,11 @@ impl Scope {
   }
 
   /// Extend the allowed patterns with the given directory.
   ///
   /// After this function has been called, the frontend will be able to use the Tauri API to read
-  /// the directory and all of its files and subdirectories.
+  /// the directory and all of its files. If `recursive` is `true`, subdirectories will be accessible too.
   pub fn allow_directory<P: AsRef<Path>>(&self, path: P, recursive: bool) -> crate::Result<()> {
     let path = path.as_ref();
     {
       let mut list = self.allowed_patterns.lock().unwrap();
 
@@ -214,27 +214,36 @@ impl Scope {
       std::fs::canonicalize(path).map_err(Into::into)
     };
 
     if let Ok(path) = path {
       let path: PathBuf = path.components().collect();
+      let options = glob::MatchOptions {
+        // this is needed so `/dir/*` doesn't match files within subdirectories such as `/dir/subdir/file.txt`
+        // see: https://github.com/tauri-apps/tauri/security/advisories/GHSA-6mv3-wm7j-h4w5
+        require_literal_separator: true,
+        // dotfiles are not supposed to be exposed by default
+        #[cfg(unix)]
+        require_literal_leading_dot: true,
+        ..Default::default()
+      };
 
       let forbidden = self
         .forbidden_patterns
         .lock()
         .unwrap()
         .iter()
-        .any(|p| p.matches_path(&path));
+        .any(|p| p.matches_path_with(&path, options));
 
       if forbidden {
         false
       } else {
         let allowed = self
           .allowed_patterns
           .lock()
           .unwrap()
           .iter()
-          .any(|p| p.matches_path(&path));
+          .any(|p| p.matches_path_with(&path, options));
         allowed
       }
     } else {
       false
     }
@@ -267,34 +276,99 @@ mod tests {
   }
 
   #[test]
   fn path_is_escaped() {
     let scope = new_scope();
-    scope.allow_directory("/home/tauri/**", false).unwrap();
-    assert!(scope.is_allowed("/home/tauri/**"));
-    assert!(scope.is_allowed("/home/tauri/**/file"));
-    assert!(!scope.is_allowed("/home/tauri/anyfile"));
+    #[cfg(unix)]
+    {
+      scope.allow_directory("/home/tauri/**", false).unwrap();
+      assert!(scope.is_allowed("/home/tauri/**"));
+      assert!(scope.is_allowed("/home/tauri/**/file"));
+      assert!(!scope.is_allowed("/home/tauri/anyfile"));
+    }
+    #[cfg(windows)]
+    {
+      scope.allow_directory("C:\\home\\tauri\\**", false).unwrap();
+      assert!(scope.is_allowed("C:\\home\\tauri\\**"));
+      assert!(scope.is_allowed("C:\\home\\tauri\\**\\file"));
+      assert!(!scope.is_allowed("C:\\home\\tauri\\anyfile"));
+    }
 
     let scope = new_scope();
-    scope.allow_file("/home/tauri/**").unwrap();
-    assert!(scope.is_allowed("/home/tauri/**"));
-    assert!(!scope.is_allowed("/home/tauri/**/file"));
-    assert!(!scope.is_allowed("/home/tauri/anyfile"));
+    #[cfg(unix)]
+    {
+      scope.allow_file("/home/tauri/**").unwrap();
+      assert!(scope.is_allowed("/home/tauri/**"));
+      assert!(!scope.is_allowed("/home/tauri/**/file"));
+      assert!(!scope.is_allowed("/home/tauri/anyfile"));
+    }
+    #[cfg(windows)]
+    {
+      scope.allow_file("C:\\home\\tauri\\**").unwrap();
+      assert!(scope.is_allowed("C:\\home\\tauri\\**"));
+      assert!(!scope.is_allowed("C:\\home\\tauri\\**\\file"));
+      assert!(!scope.is_allowed("C:\\home\\tauri\\anyfile"));
+    }
+
+    let scope = new_scope();
+    #[cfg(unix)]
+    {
+      scope.allow_directory("/home/tauri", true).unwrap();
+      scope.forbid_directory("/home/tauri/**", false).unwrap();
+      assert!(!scope.is_allowed("/home/tauri/**"));
+      assert!(!scope.is_allowed("/home/tauri/**/file"));
+      assert!(scope.is_allowed("/home/tauri/**/inner/file"));
+      assert!(scope.is_allowed("/home/tauri/inner/folder/anyfile"));
+      assert!(scope.is_allowed("/home/tauri/anyfile"));
+    }
+    #[cfg(windows)]
+    {
+      scope.allow_directory("C:\\home\\tauri", true).unwrap();
+      scope
+        .forbid_directory("C:\\home\\tauri\\**", false)
+        .unwrap();
+      assert!(!scope.is_allowed("C:\\home\\tauri\\**"));
+      assert!(!scope.is_allowed("C:\\home\\tauri\\**\\file"));
+      assert!(scope.is_allowed("C:\\home\\tauri\\**\\inner\\file"));
+      assert!(scope.is_allowed("C:\\home\\tauri\\inner\\folder\\anyfile"));
+      assert!(scope.is_allowed("C:\\home\\tauri\\anyfile"));
+    }
 
     let scope = new_scope();
-    scope.allow_directory("/home/tauri", true).unwrap();
-    scope.forbid_directory("/home/tauri/**", false).unwrap();
-    assert!(!scope.is_allowed("/home/tauri/**"));
-    assert!(!scope.is_allowed("/home/tauri/**/file"));
-    assert!(!scope.is_allowed("/home/tauri/**/inner/file"));
-    assert!(scope.is_allowed("/home/tauri/inner/folder/anyfile"));
-    assert!(scope.is_allowed("/home/tauri/anyfile"));
+    #[cfg(unix)]
+    {
+      scope.allow_directory("/home/tauri", true).unwrap();
+      scope.forbid_file("/home/tauri/**").unwrap();
+      assert!(!scope.is_allowed("/home/tauri/**"));
+      assert!(scope.is_allowed("/home/tauri/**/file"));
+      assert!(scope.is_allowed("/home/tauri/**/inner/file"));
+      assert!(scope.is_allowed("/home/tauri/anyfile"));
+    }
+    #[cfg(windows)]
+    {
+      scope.allow_directory("C:\\home\\tauri", true).unwrap();
+      scope.forbid_file("C:\\home\\tauri\\**").unwrap();
+      assert!(!scope.is_allowed("C:\\home\\tauri\\**"));
+      assert!(scope.is_allowed("C:\\home\\tauri\\**\\file"));
+      assert!(scope.is_allowed("C:\\home\\tauri\\**\\inner\\file"));
+      assert!(scope.is_allowed("C:\\home\\tauri\\anyfile"));
+    }
 
     let scope = new_scope();
-    scope.allow_directory("/home/tauri", true).unwrap();
-    scope.forbid_file("/home/tauri/**").unwrap();
-    assert!(!scope.is_allowed("/home/tauri/**"));
-    assert!(scope.is_allowed("/home/tauri/**/file"));
-    assert!(scope.is_allowed("/home/tauri/**/inner/file"));
-    assert!(scope.is_allowed("/home/tauri/anyfile"));
+    #[cfg(unix)]
+    {
+      scope.allow_directory("/home/tauri", false).unwrap();
+      assert!(scope.is_allowed("/home/tauri/**"));
+      assert!(!scope.is_allowed("/home/tauri/**/file"));
+      assert!(!scope.is_allowed("/home/tauri/**/inner/file"));
+      assert!(scope.is_allowed("/home/tauri/anyfile"));
+    }
+    #[cfg(windows)]
+    {
+      scope.allow_directory("C:\\home\\tauri", false).unwrap();
+      assert!(scope.is_allowed("C:\\home\\tauri\\**"));
+      assert!(!scope.is_allowed("C:\\home\\tauri\\**\\file"));
+      assert!(!scope.is_allowed("C:\\home\\tauri\\**\\inner\\file"));
+      assert!(scope.is_allowed("C:\\home\\tauri\\anyfile"));
+    }
   }
 }

Vulnerable code:   /// the directory and all of its files and subdirectories.
        .any(|p| p.matches_path(&path));
          .any(|p| p.matches_path(&path));
    scope.allow_directory("/home/tauri/**", false).unwrap();
    assert!(scope.is_allowed("/home/tauri/**"));
    assert!(scope.is_allowed("/home/tauri/**/file"));
    assert!(!scope.is_allowed("/home/tauri/anyfile"));
    scope.allow_file("/home/tauri/**").unwrap();
    assert!(scope.is_allowed("/home/tauri/**"));
    assert!(!scope.is_allowed("/home/tauri/**/file"));
    assert!(!scope.is_allowed("/home/tauri/anyfile"));
    scope.allow_directory("/home/tauri", true).unwrap();
    scope.forbid_directory("/home/tauri/**", false).unwrap();
    assert!(!scope.is_allowed("/home/tauri/**"));
    assert!(!scope.is_allowed("/home/tauri/**/file"));
    assert!(!scope.is_allowed("/home/tauri/**/inner/file"));
    assert!(scope.is_allowed("/home/tauri/inner/folder/anyfile"));
    assert!(scope.is_allowed("/home/tauri/anyfile"));
    scope.allow_directory("/home/tauri", true).unwrap();
    scope.forbid_file("/home/tauri/**").unwrap();
    assert!(!scope.is_allowed("/home/tauri/**"));
    assert!(scope.is_allowed("/home/tauri/**/file"));
    assert!(scope.is_allowed("/home/tauri/**/inner/file"));
    assert!(scope.is_allowed("/home/tauri/anyfile"));
Fixed code: ---
"tauri": "patch"
---

Fix the filesystem scope allowing sub-directories of the directory picked by the dialog when `recursive` option was `false`.
  /// the directory and all of its files. If `recursive` is `true`, subdirectories will be accessible too.
      let options = glob::MatchOptions {
        // this is needed so `/dir/*` doesn't match files within subdirectories such as `/dir/subdir/file.txt`
        // see: https://github.com/tauri-apps/tauri/security/advisories/GHSA-6mv3-wm7j-h4w5
        require_literal_separator: true,
        // dotfiles are not supposed to be exposed by default
        #[cfg(unix)]
        require_literal_leading_dot: true,
        ..Default::default()
      };
        .any(|p| p.matches_path_with(&path, options));
          .any(|p| p.matches_path_with(&path, options));
    #[cfg(unix)]
    {
      scope.allow_directory("/home/tauri/**", false).unwrap();
      assert!(scope.is_allowed("/home/tauri/**"));
      assert!(scope.is_allowed("/home/tauri/**/file"));
      assert!(!scope.is_allowed("/home/tauri/anyfile"));
    }
    #[cfg(windows)]
    {
      scope.allow_directory("C:\\home\\tauri\\**", false).unwrap();
      assert!(scope.is_allowed("C:\\home\\tauri\\**"));
      assert!(scope.is_allowed("C:\\home\\tauri\\**\\file"));
      assert!(!scope.is_allowed("C:\\home\\tauri\\anyfile"));
    }
    #[cfg(unix)]
    {
      scope.allow_file("/home/tauri/**").unwrap();
      assert!(scope.is_allowed("/home/tauri/**"));
      assert!(!scope.is_allowed("/home/tauri/**/file"));
      assert!(!scope.is_allowed("/home/tauri/anyfile"));
    }
    #[cfg(windows)]
    {
      scope.allow_file("C:\\home\\tauri\\**").unwrap();
      assert!(scope.is_allowed("C:\\home\\tauri\\**"));
      assert!(!scope.is_allowed("C:\\home\\tauri\\**\\file"));
      assert!(!scope.is_allowed("C:\\home\\tauri\\anyfile"));
    }

    let scope = new_scope();
    #[cfg(unix)]
    {
      scope.allow_directory("/home/tauri", true).unwrap();
      scope.forbid_directory("/home/tauri/**", false).unwrap();
      assert!(!scope.is_allowed("/home/tauri/**"));
      assert!(!scope.is_allowed("/home/tauri/**/file"));
      assert!(scope.is_allowed("/home/tauri/**/inner/file"));
      assert!(scope.is_allowed("/home/tauri/inner/folder/anyfile"));
      assert!(scope.is_allowed("/home/tauri/anyfile"));
    }
    #[cfg(windows)]
    {
      scope.allow_directory("C:\\home\\tauri", true).unwrap();
      scope
        .forbid_directory("C:\\home\\tauri\\**", false)
        .unwrap();
      assert!(!scope.is_allowed("C:\\home\\tauri\\**"));
      assert!(!scope.is_allowed("C:\\home\\tauri\\**\\file"));
      assert!(scope.is_allowed("C:\\home\\tauri\\**\\inner\\file"));
      assert!(scope.is_allowed("C:\\home\\tauri\\inner\\folder\\anyfile"));
      assert!(scope.is_allowed("C:\\home\\tauri\\anyfile"));
    }
    #[cfg(unix)]
    {
      scope.allow_directory("/home/tauri", true).unwrap();
      scope.forbid_file("/home/tauri/**").unwrap();
      assert!(!scope.is_allowed("/home/tauri/**"));
      assert!(scope.is_allowed("/home/tauri/**/file"));
      assert!(scope.is_allowed("/home/tauri/**/inner/file"));
      assert!(scope.is_allowed("/home/tauri/anyfile"));
    }
    #[cfg(windows)]
    {
      scope.allow_directory("C:\\home\\tauri", true).unwrap();
      scope.forbid_file("C:\\home\\tauri\\**").unwrap();
      assert!(!scope.is_allowed("C:\\home\\tauri\\**"));
      assert!(scope.is_allowed("C:\\home\\tauri\\**\\file"));
      assert!(scope.is_allowed("C:\\home\\tauri\\**\\inner\\file"));
      assert!(scope.is_allowed("C:\\home\\tauri\\anyfile"));
    }
    #[cfg(unix)]
    {
      scope.allow_directory("/home/tauri", false).unwrap();
      assert!(scope.is_allowed("/home/tauri/**"));
      assert!(!scope.is_allowed("/home/tauri/**/file"));
      assert!(!scope.is_allowed("/home/tauri/**/inner/file"));
      assert!(scope.is_allowed("/home/tauri/anyfile"));
    }
    #[cfg(windows)]
    {
      scope.allow_directory("C:\\home\\tauri", false).unwrap();
      assert!(scope.is_allowed("C:\\home\\tauri\\**"));
      assert!(!scope.is_allowed("C:\\home\\tauri\\**\\file"));
      assert!(!scope.is_allowed("C:\\home\\tauri\\**\\inner\\file"));
      assert!(scope.is_allowed("C:\\home\\tauri\\anyfile"));
    }