linux_dsm_epyc7002/init
Eric W. Biederman 499dcf2024 userns: Support fuse interacting with multiple user namespaces
Use kuid_t and kgid_t in struct fuse_conn and struct fuse_mount_data.

The connection between between a fuse filesystem and a fuse daemon is
established when a fuse filesystem is mounted and provided with a file
descriptor the fuse daemon created by opening /dev/fuse.

For now restrict the communication of uids and gids between the fuse
filesystem and the fuse daemon to the initial user namespace.  Enforce
this by verifying the file descriptor passed to the mount of fuse was
opened in the initial user namespace.  Ensuring the mount happens in
the initial user namespace is not necessary as mounts from non-initial
user namespaces are not yet allowed.

In fuse_req_init_context convert the currrent fsuid and fsgid into the
initial user namespace for the request that will be sent to the fuse
daemon.

In fuse_fill_attr convert the uid and gid passed from the fuse daemon
from the initial user namespace into kuids and kgids.

In iattr_to_fattr called from fuse_setattr convert kuids and kgids
into the uids and gids in the initial user namespace before passing
them to the fuse filesystem.

In fuse_change_attributes_common called from fuse_dentry_revalidate,
fuse_permission, fuse_geattr, and fuse_setattr, and fuse_iget convert
the uid and gid from the fuse daemon into a kuid and a kgid to store
on the fuse inode.

By default fuse mounts are restricted to task whose uid, suid, and
euid matches the fuse user_id and whose gid, sgid, and egid matches
the fuse group id.  Convert the user_id and group_id mount options
into kuids and kgids at mount time, and use uid_eq and gid_eq to
compare the in fuse_allow_task.

Cc: Miklos Szeredi <miklos@szeredi.hu>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2012-11-14 22:05:33 -08:00
..
calibrate.c init: check printed flag to skip printing message 2012-03-23 16:58:38 -07:00
do_mounts_initrd.c don't bother with kernel_thread/kernel_execve for launching linuxrc 2012-10-11 21:40:30 -04:00
do_mounts_md.c init: disable sparse checking of the mount.o source files 2012-05-31 17:49:27 -07:00
do_mounts_rd.c init: disable sparse checking of the mount.o source files 2012-05-31 17:49:27 -07:00
do_mounts.c vfs: allocate page instead of names_cache buffer in mount_block_root 2012-10-12 00:32:03 -04:00
do_mounts.h md: move lots of #include lines out of .h files and into .c 2009-03-31 14:33:13 +11:00
init_task.c init_task: Create generic init_task instance 2012-05-05 13:00:21 +02:00
initramfs.c init: disable sparse checking of the mount.o source files 2012-05-31 17:49:27 -07:00
Kconfig userns: Support fuse interacting with multiple user namespaces 2012-11-14 22:05:33 -08:00
main.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal 2012-10-13 10:05:52 +09:00
Makefile init_task: Replace CONFIG_HAVE_GENERIC_INIT_TASK 2012-05-05 13:00:46 +02:00
noinitramfs.c init: mark __user address space on string literals 2010-10-26 16:52:15 -07:00
version.c userns: add a user_namespace as creator/owner of uts_namespace 2011-03-23 19:46:59 -07:00