Vulnerabilidades do Containers Crun

A flaw was found in crun. When the container configuration does not give /dev a dedicated mount, terminal setup can redirect /dev/console onto an attacker-controlled path, including via the read-only-rootfs bind-mount fallback. Affected versions are crun 1.29.1 and earlier. Default configurations that mount a fresh /dev are not exposed. No fixed release is available yet.

crun is an open source OCI Container Runtime fully written in C. Prior to version 1.28, crun's default device setup opens the container rootfs `/dev` directory without `O_NOFOLLOW`. If an OCI bundle contains `rootfs/dev` as a symlink and the bundle configuration does not mount `/dev`, crun follows that symlink and creates the default device nodes and stdio symlinks at the symlink target outside the container rootfs. In a local rootful crun replay, this created fixed device nodes and symlinks outside the rootfs before crun returned failure. A pre-existing file named `ptmx` in the target directory was also replaced by crun's forced `ptmx -> pts/ptmx` symlink. Version 1.28 fixes the issue.