Newlines in virtiofs tags are awkward for users and potential vectors
for string injection attacks.
Signed-off-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx>
---
fs/fuse/virtio_fs.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c
index 5f1be1da92ce..d84dacbdce2c 100644
--- a/fs/fuse/virtio_fs.c
+++ b/fs/fuse/virtio_fs.c
@@ -323,6 +323,16 @@ static int virtio_fs_read_tag(struct virtio_device *vdev, struct virtio_fs *fs)
return -ENOMEM;
memcpy(fs->tag, tag_buf, len);
fs->tag[len] = '\0';
+
+ /* While the VIRTIO specification allows any character, newlines are
+ * awkward on mount(8) command-lines and cause problems in the sysfs
+ * "tag" attr and uevent TAG= properties. Forbid them.
+ */
+ if (strchr(fs->tag, '\n')) {
+ dev_dbg(&vdev->dev, "refusing virtiofs tag with newline character\n");
+ return -EINVAL;
+ }
+
return 0;
}
--
2.43.0
