original_kernel/Documentation/bpf/fs_kfuncs.rst

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.. SPDX-License-Identifier: GPL-2.0
.. _fs_kfuncs-header-label:
=====================
BPF filesystem kfuncs
=====================
BPF LSM programs need to access filesystem data from LSM hooks. The following
BPF kfuncs can be used to get these data.
* ``bpf_get_file_xattr()``
* ``bpf_get_fsverity_digest()``
To avoid recursions, these kfuncs follow the following rules:
1. These kfuncs are only permitted from BPF LSM function.
2. These kfuncs should not call into other LSM hooks, i.e. security_*(). For
example, ``bpf_get_file_xattr()`` does not use ``vfs_getxattr()``, because
the latter calls LSM hook ``security_inode_getxattr``.