Improper Input Validation

Summary

A vulnerability exists in the "bind-propagation" option of the Dockerfile "RUN --mount" instruction. The system does not properly validate the input passed to this option, allowing users to pass arbitrary parameters to the mount instruction. This issue can be exploited to mount sensitive directories from the host into a container during the build process and, in some cases, modify the contents of those mounted files. Even if "SELinux" is used, this vulnerability can bypass its protection by allowing the source directory to be relabeled, giving the container access to host files. This issue affects github.com/containers/podman package versions prior to 5.2.4, and github.com/containers/buildah package versions prior to 1.37.4.