linux/fs/nfs_common/nfsacl.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * fs/nfs_common/nfsacl.c
 *
 *  Copyright (C) 2002-2003 Andreas Gruenbacher <[email protected]>
 */

/*
 * The Solaris nfsacl protocol represents some ACLs slightly differently
 * than POSIX 1003.1e draft 17 does (and we do):
 *
 *  - Minimal ACLs always have an ACL_MASK entry, so they have
 *    four instead of three entries.
 *  - The ACL_MASK entry in such minimal ACLs always has the same
 *    permissions as the ACL_GROUP_OBJ entry. (In extended ACLs
 *    the ACL_MASK and ACL_GROUP_OBJ entries may differ.)
 *  - The identifier fields of the ACL_USER_OBJ and ACL_GROUP_OBJ
 *    entries contain the identifiers of the owner and owning group.
 *    (In POSIX ACLs we always set them to ACL_UNDEFINED_ID).
 *  - ACL entries in the kernel are kept sorted in ascending order
 *    of (e_tag, e_id). Solaris ACLs are unsorted.
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/gfp.h>
#include <linux/sunrpc/xdr.h>
#include <linux/nfsacl.h>
#include <linux/nfs3.h>
#include <linux/sort.h>

MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;

struct nfsacl_encode_desc { … };

struct nfsacl_simple_acl { … };

static int
xdr_nfsace_encode(struct xdr_array2_desc *desc, void *elem)
{ … }

/**
 * nfsacl_encode - Encode an NFSv3 ACL
 *
 * @buf: destination xdr_buf to contain XDR encoded ACL
 * @base: byte offset in xdr_buf where XDR'd ACL begins
 * @inode: inode of file whose ACL this is
 * @acl: posix_acl to encode
 * @encode_entries: whether to encode ACEs as well
 * @typeflag: ACL type: NFS_ACL_DEFAULT or zero
 *
 * Returns size of encoded ACL in bytes or a negative errno value.
 */
int nfsacl_encode(struct xdr_buf *buf, unsigned int base, struct inode *inode,
		  struct posix_acl *acl, int encode_entries, int typeflag)
{ … }
EXPORT_SYMBOL_GPL(…);

/**
 * nfs_stream_encode_acl - Encode an NFSv3 ACL
 *
 * @xdr: an xdr_stream positioned to receive an encoded ACL
 * @inode: inode of file whose ACL this is
 * @acl: posix_acl to encode
 * @encode_entries: whether to encode ACEs as well
 * @typeflag: ACL type: NFS_ACL_DEFAULT or zero
 *
 * Return values:
 *   %false: The ACL could not be encoded
 *   %true: @xdr is advanced to the next available position
 */
bool nfs_stream_encode_acl(struct xdr_stream *xdr, struct inode *inode,
			   struct posix_acl *acl, int encode_entries,
			   int typeflag)
{ … }
EXPORT_SYMBOL_GPL(…);


struct nfsacl_decode_desc { … };

static int
xdr_nfsace_decode(struct xdr_array2_desc *desc, void *elem)
{ … }

static int
cmp_acl_entry(const void *x, const void *y)
{ … }

/*
 * Convert from a Solaris ACL to a POSIX 1003.1e draft 17 ACL.
 */
static int
posix_acl_from_nfsacl(struct posix_acl *acl)
{ … }

/**
 * nfsacl_decode - Decode an NFSv3 ACL
 *
 * @buf: xdr_buf containing XDR'd ACL data to decode
 * @base: byte offset in xdr_buf where XDR'd ACL begins
 * @aclcnt: count of ACEs in decoded posix_acl
 * @pacl: buffer in which to place decoded posix_acl
 *
 * Returns the length of the decoded ACL in bytes, or a negative errno value.
 */
int nfsacl_decode(struct xdr_buf *buf, unsigned int base, unsigned int *aclcnt,
		  struct posix_acl **pacl)
{ … }
EXPORT_SYMBOL_GPL(…);

/**
 * nfs_stream_decode_acl - Decode an NFSv3 ACL
 *
 * @xdr: an xdr_stream positioned at an encoded ACL
 * @aclcnt: OUT: count of ACEs in decoded posix_acl
 * @pacl: OUT: a dynamically-allocated buffer containing the decoded posix_acl
 *
 * Return values:
 *   %false: The encoded ACL is not valid
 *   %true: @pacl contains a decoded ACL, and @xdr is advanced
 *
 * On a successful return, caller must release *pacl using posix_acl_release().
 */
bool nfs_stream_decode_acl(struct xdr_stream *xdr, unsigned int *aclcnt,
			   struct posix_acl **pacl)
{ … }
EXPORT_SYMBOL_GPL(…);