fix: ignore invalid unix permissions and setuid bits from zip

src/archive/zip.rs

@@ -315,7 +315,15 @@ fn unix_set_permissions<R: Read>(file_path: &Path, file: &ZipFile<'_, R>) -> Res
     use std::fs::Permissions;
 
     if let Some(mode) = file.unix_mode() {
-        fs::set_permissions(file_path, Permissions::from_mode(mode))?;
+        // Zip crate may return invalid Unix modes derived from MS-DOS attributes.
+        // Valid Unix modes contain the file type bits (S_IFMT, 0o170000).
+        // If these bits are missing, the mode is likely invalid and should be ignored.
+        // Also, we mask out the setuid, setgid, and sticky bits (0o7777 -> 0o0777)
+        // for security reasons when decompressing.
+        if mode & 0o170000 != 0 {
+            let safe_mode = mode & 0o777;
+            fs::set_permissions(file_path, Permissions::from_mode(safe_mode))?;
+        }
     }
 
     Ok(())

tests/integration.rs

@@ -1569,3 +1569,52 @@ fn decompress_concatenated_lz4_frames() {
         encoder.finish().unwrap()
     });
 }
+
+/// Ensure extracting zip archives lacking correct UNIX file type bits (e.g. MS-DOS attributes mapped poorly)
+/// won't wrongly apply setuid/setgid bits.
+#[test]
+fn missing_file_type_unix_permissions() {
+    let (_tempdir, test_dir) = testdir().unwrap();
+
+    let bad_perms_zip = test_dir.join("bad_perms.zip");
+
+    {
+        use zip::write::SimpleFileOptions;
+
+        let file = std::fs::File::create(&bad_perms_zip).unwrap();
+        let mut zip = zip::ZipWriter::new(file);
+
+        // Use an invalid mode: 0o7700 (missing S_IFMT)
+        let options = SimpleFileOptions::default().unix_permissions(0o7700);
+        zip.start_file("test_file.txt", options).unwrap();
+        zip.write_all(b"hello world").unwrap();
+        zip.finish().unwrap();
+    }
+
+    let out_dir = test_dir.join("out");
+
+    let mut cmd = crate::utils::cargo_bin();
+    cmd.arg("d")
+        .arg(&bad_perms_zip)
+        .arg("-d")
+        .arg(&out_dir)
+        .assert()
+        .success();
+
+    #[cfg(unix)]
+    {
+        use std::os::unix::fs::PermissionsExt;
+        let file_path = out_dir.join("test_file.txt");
+        let metadata = std::fs::metadata(&file_path).unwrap();
+        let mode = metadata.permissions().mode();
+
+        // Default permission should be applied since 0o7700 does not have file type bits.
+        // It definitely shouldn't be 0o7700 or have sticky/setuid bits.
+        assert_ne!(
+            mode & 0o7777,
+            0o7700,
+            "Should have fallen back to default file permissions"
+        );
+        assert_eq!(mode & 0o7000, 0, "Should not have sticky, setuid, or setgid bits");
+    }
+}