mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-08-30 14:33:24 -04:00
d64ba78b74
fsopen() records the caller's user namespace in fc->user_ns and hands back an ordinary file descriptor, so the task that issues FSCONFIG_CMD_CREATE need not be the one that created the context. mount_capable() authorizes that for a caller holding CAP_SYS_ADMIN in an ancestor of fc->user_ns, which any unprivileged user has over a user namespace it just created. binfmt_misc and overlayfs used to WARN_ON() the mismatch. Add a test for both. Also cover the handover within one user namespace. That is a supported thing to do and has to keep working. Link: https://patch.msgid.link/20260802-work-fill_super-warn-v1-3-4e987911a39a@kernel.org Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>