linux-toradex.git/include/uapi/linux/fuse.h, branch v5.12-rc6

fuse: 32-bit user space ioctl compat for fuse device

2021-03-16T14:20:16+00:00

With a 64-bit kernel build the FUSE device cannot handle ioctl requests
coming from 32-bit user space.  This is due to the ioctl command
translation that generates different command identifiers that thus cannot
be used for direct comparisons without proper manipulation.

Explicitly extract type and number from the ioctl command to enable 32-bit
user space compatibility on 64-bit kernel builds.

Signed-off-by: Alessio Balsini 
Signed-off-by: Miklos Szeredi

fuse: add a flag FUSE_OPEN_KILL_SUIDGID for open() request

2020-11-11T16:22:33+00:00

With FUSE_HANDLE_KILLPRIV_V2 support, server will need to kill suid/sgid/
security.capability on open(O_TRUNC), if server supports
FUSE_ATOMIC_O_TRUNC.

But server needs to kill suid/sgid only if caller does not have CAP_FSETID.
Given server does not have this information, client needs to send this info
to server.

So add a flag FUSE_OPEN_KILL_SUIDGID to fuse_open_in request which tells
server to kill suid/sgid (only if group execute is set).

This flag is added to the FUSE_OPEN request, as well as the FUSE_CREATE
request if the create was non-exclusive, since that might result in an
existing file being opened/truncated.

Signed-off-by: Vivek Goyal 
Signed-off-by: Miklos Szeredi

fuse: setattr should set FATTR_KILL_SUIDGID

2020-11-11T16:22:33+00:00

If fc->handle_killpriv_v2 is enabled, we expect file server to clear
suid/sgid/security.capbility upon chown/truncate/write as appropriate.

Upon truncate (ATTR_SIZE), suid/sgid are cleared only if caller does not
have CAP_FSETID.  File server does not know whether caller has CAP_FSETID
or not.  Hence set FATTR_KILL_SUIDGID upon truncate to let file server know
that caller does not have CAP_FSETID and it should kill suid/sgid as
appropriate.

On chown (ATTR_UID/ATTR_GID) suid/sgid need to be cleared irrespective of
capabilities of calling process, so set FATTR_KILL_SUIDGID unconditionally
in that case.

Signed-off-by: Vivek Goyal 
Signed-off-by: Miklos Szeredi

fuse: rename FUSE_WRITE_KILL_PRIV to FUSE_WRITE_KILL_SUIDGID

2020-11-11T16:22:32+00:00

Kernel has:
ATTR_KILL_PRIV -> clear "security.capability"
ATTR_KILL_SUID -> clear S_ISUID
ATTR_KILL_SGID -> clear S_ISGID if executable

Fuse has:
FUSE_WRITE_KILL_PRIV -> clear S_ISUID and S_ISGID if executable

So FUSE_WRITE_KILL_PRIV implies the complement of ATTR_KILL_PRIV, which is
somewhat confusing.  Also PRIV implies all privileges, including
"security.capability".

Change the name to FUSE_WRITE_KILL_SUIDGID and make FUSE_WRITE_KILL_PRIV an
alias to perserve API compatibility

Signed-off-by: Miklos Szeredi

fuse: introduce the notion of FUSE_HANDLE_KILLPRIV_V2

2020-11-11T16:22:32+00:00

We already have FUSE_HANDLE_KILLPRIV flag that says that file server will
remove suid/sgid/caps on truncate/chown/write. But that's little different
from what Linux VFS implements.

To be consistent with Linux VFS behavior what we want is.

- caps are always cleared on chown/write/truncate
- suid is always cleared on chown, while for truncate/write it is cleared
  only if caller does not have CAP_FSETID.
- sgid is always cleared on chown, while for truncate/write it is cleared
  only if caller does not have CAP_FSETID as well as file has group execute
  permission.

As previous flag did not provide above semantics. Implement a V2 of the
protocol with above said constraints.

Server does not know if caller has CAP_FSETID or not. So for the case
of write()/truncate(), client will send information in special flag to
indicate whether to kill priviliges or not. These changes are in subsequent
patches.

FUSE_HANDLE_KILLPRIV_V2 relies on WRITE being sent to server to clear
suid/sgid/security.capability. But with ->writeback_cache, WRITES are
cached in guest. So it is not recommended to use FUSE_HANDLE_KILLPRIV_V2
and writeback_cache together. Though it probably might be good enough
for lot of use cases.

Signed-off-by: Vivek Goyal 
Signed-off-by: Miklos Szeredi

fuse: add submount support to

2020-09-18T13:17:40+00:00

- Add fuse_attr.flags

- Add FUSE_ATTR_SUBMOUNT

  This is a flag for fuse_attr.flags that indicates that the given entry
  resides on a different filesystem than the parent, and as such should
  have a different st_dev.

- Add FUSE_SUBMOUNTS

  The client sets this flag if it supports automounting directories.

Signed-off-by: Max Reitz 
Signed-off-by: Miklos Szeredi

virtiofs: implement dax read/write operations

2020-09-10T09:39:23+00:00

This patch implements basic DAX support. mmap() is not implemented
yet and will come in later patches. This patch looks into implemeting
read/write.

We make use of interval tree to keep track of per inode dax mappings.

Do not use dax for file extending writes, instead just send WRITE message
to daemon (like we do for direct I/O path). This will keep write and
i_size change atomic w.r.t crash.

Signed-off-by: Stefan Hajnoczi 
Signed-off-by: Dr. David Alan Gilbert 
Signed-off-by: Vivek Goyal 
Signed-off-by: Liu Bo 
Signed-off-by: Peng Tao 
Cc: Dave Chinner 
Signed-off-by: Miklos Szeredi

virtiofs: introduce setupmapping/removemapping commands

2020-09-10T09:39:23+00:00

Introduce two new fuse commands to setup/remove memory mappings. This
will be used to setup/tear down file mapping in dax window.

Signed-off-by: Vivek Goyal 
Signed-off-by: Peng Tao 
Signed-off-by: Miklos Szeredi

virtiofs: implement FUSE_INIT map_alignment field

2020-09-10T09:39:22+00:00

The device communicates FUSE_SETUPMAPPING/FUSE_REMOVMAPPING alignment
constraints via the FUST_INIT map_alignment field.  Parse this field and
ensure our DAX mappings meet the alignment constraints.

We don't actually align anything differently since our mappings are
already 2MB aligned.  Just check the value when the connection is
established.  If it becomes necessary to honor arbitrary alignments in
the future we'll have to adjust how mappings are sized.

The upshot of this commit is that we can be confident that mappings will
work even when emulating x86 on Power and similar combinations where the
host page sizes are different.

Signed-off-by: Stefan Hajnoczi 
Signed-off-by: Vivek Goyal 
Signed-off-by: Miklos Szeredi

fuse: Add changelog entries for protocols 7.1 - 7.8

2019-10-23T12:26:37+00:00

Retroactively add changelog entry for FUSE protocols 7.1 through 7.8.

Signed-off-by: Alan Somers 
Signed-off-by: Miklos Szeredi