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Merge tag 'vfs-6.7-rc3.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs fixes from Christian Brauner:
- Avoid calling back into LSMs from vfs_getattr_nosec() calls.
IMA used to query inode properties accessing raw inode fields without
dedicated helpers. That was finally fixed a few releases ago by
forcing IMA to use vfs_getattr_nosec() helpers.
The goal of the vfs_getattr_nosec() helper is to query for attributes
without calling into the LSM layer which would be quite problematic
because incredibly IMA is called from __fput()...
__fput()
-> ima_file_free()
What it does is to call back into the filesystem to update the file's
IMA xattr. Querying the inode without using vfs_getattr_nosec() meant
that IMA didn't handle stacking filesystems such as overlayfs
correctly. So the switch to vfs_getattr_nosec() is quite correct. But
the switch to vfs_getattr_nosec() revealed another bug when used on
stacking filesystems:
__fput()
-> ima_file_free()
-> vfs_getattr_nosec()
-> i_op->getattr::ovl_getattr()
-> vfs_getattr()
-> i_op->getattr::$WHATEVER_UNDERLYING_FS_getattr()
-> security_inode_getattr() # calls back into LSMs
Now, if that __fput() happens from task_work_run() of an exiting task
current->fs and various other pointer could already be NULL. So
anything in the LSM layer relying on that not being NULL would be
quite surprised.
Fix that by passing the information that this is a security request
through to the stacking filesystem by adding a new internal
ATT_GETATTR_NOSEC flag. Now the callchain becomes:
__fput()
-> ima_file_free()
-> vfs_getattr_nosec()
-> i_op->getattr::ovl_getattr()
-> if (AT_GETATTR_NOSEC)
vfs_getattr_nosec()
else
vfs_getattr()
-> i_op->getattr::$WHATEVER_UNDERLYING_FS_getattr()
- Fix a bug introduced with the iov_iter rework from last cycle.
This broke /proc/kcore by copying too much and without the correct
offset.
- Add a missing NULL check when allocating the root inode in
autofs_fill_super().
- Fix stable writes for multi-device filesystems (xfs, btrfs etc) and
the block device pseudo filesystem.
Stable writes used to be a superblock flag only, making it a per
filesystem property. Add an additional AS_STABLE_WRITES mapping flag
to allow for fine-grained control.
- Ensure that offset_iterate_dir() returns 0 after reaching the end of
a directory so it adheres to getdents() convention.
* tag 'vfs-6.7-rc3.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
libfs: getdents() should return 0 after reaching EOD
xfs: respect the stable writes flag on the RT device
xfs: clean up FS_XFLAG_REALTIME handling in xfs_ioctl_setattr_xflags
block: update the stable_writes flag in bdev_add
filemap: add a per-mapping stable writes flag
autofs: add: new_inode check in autofs_fill_super()
iov_iter: fix copy_page_to_iter_nofault()
fs: Pass AT_GETATTR_NOSEC flag to getattr interface function
fa2b906f51