dir: Use fd-relative operations for files/etc during runtime deploy

Browse Source

The runtime deploy path used GFile operations to manipulate files
inside files/etc (passwd, group, machine-id, resolv.conf). While
the "files" directory is validated with glnx_chaseat using
GLNX_CHASE_RESOLVE_NO_SYMLINKS, "etc" inside it is not checked.
A malicious runtime with files/etc as a symlink causes the GFile
operations (g_file_delete, g_file_replace_contents,
g_file_make_symbolic_link) to follow it and modify files at the
symlink target. On system installs (running as root), this modifies
arbitrary files — e.g. replacing /etc/resolv.conf.

This commit uses fd-based operations to prevent to prevent the symlink
attack.

Resolves: CVE-2026-97024
Resolves: https://github.com/flatpak/flatpak/security/advisories/GHSA-8xgq-v545-vgvf

...

This commit is contained in:

500 Internal Server Error

Gitea Version: 1.28.0+dev-477-g8b6ad49a5f