freebsd-nq/include/sys/dmu_recv.h
Matthew Ahrens e59a377a8f
filesystem_limit/snapshot_limit is incorrectly enforced against root
The filesystem_limit and snapshot_limit properties limit the number of
filesystems or snapshots that can be created below this dataset.
According to the manpage, "The limit is not enforced if the user is
allowed to change the limit."  Two types of users are allowed to change
the limit:

1. Those that have been delegated the `filesystem_limit` or
`snapshot_limit` permission, e.g. with
`zfs allow USER filesystem_limit DATASET`.  This works properly.

2. A user with elevated system privileges (e.g. root).  This does not
work - the root user will incorrectly get an error when trying to create
a snapshot/filesystem, if it exceeds the `_limit` property.

The problem is that `priv_policy_ns()` does not work if the `cred_t` is
not that of the current process.  This happens when
`dsl_enforce_ds_ss_limits()` is called in syncing context (as part of a
sync task's check func) to determine the permissions of the
corresponding user process.

This commit fixes the issue by passing the `task_struct` (typedef'ed as
a `proc_t`) to syncing context, and then using `has_capability()` to
determine if that process is privileged.  Note that we still need to
pass the `cred_t` to syncing context so that we can check if the user
was delegated this permission with `zfs allow`.

This problem only impacts Linux.  Wrappers are added to FreeBSD but it
continues to use `priv_check_cred()`, which works on arbitrary `cred_t`.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #8226
Closes #10545
2020-07-11 17:18:02 -07:00

89 lines
2.8 KiB
C

/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2012, 2020 by Delphix. All rights reserved.
* Copyright 2011 Nexenta Systems, Inc. All rights reserved.
* Copyright (c) 2013, Joyent, Inc. All rights reserved.
*/
#ifndef _DMU_RECV_H
#define _DMU_RECV_H
#include <sys/inttypes.h>
#include <sys/dsl_bookmark.h>
#include <sys/dsl_dataset.h>
#include <sys/spa.h>
#include <sys/objlist.h>
#include <sys/dsl_bookmark.h>
extern const char *recv_clone_name;
typedef struct dmu_recv_cookie {
struct dsl_dataset *drc_ds;
struct dmu_replay_record *drc_drr_begin;
struct drr_begin *drc_drrb;
const char *drc_tofs;
const char *drc_tosnap;
boolean_t drc_newfs;
boolean_t drc_byteswap;
uint64_t drc_featureflags;
boolean_t drc_force;
boolean_t drc_resumable;
boolean_t drc_should_save;
boolean_t drc_raw;
boolean_t drc_clone;
boolean_t drc_spill;
nvlist_t *drc_keynvl;
uint64_t drc_fromsnapobj;
uint64_t drc_ivset_guid;
void *drc_owner;
cred_t *drc_cred;
proc_t *drc_proc;
nvlist_t *drc_begin_nvl;
objset_t *drc_os;
zfs_file_t *drc_fp; /* The file to read the stream from */
uint64_t drc_voff; /* The current offset in the stream */
uint64_t drc_bytes_read;
/*
* A record that has had its payload read in, but hasn't yet been handed
* off to the worker thread.
*/
struct receive_record_arg *drc_rrd;
/* A record that has had its header read in, but not its payload. */
struct receive_record_arg *drc_next_rrd;
zio_cksum_t drc_cksum;
zio_cksum_t drc_prev_cksum;
/* Sorted list of objects not to issue prefetches for. */
objlist_t *drc_ignore_objlist;
} dmu_recv_cookie_t;
int dmu_recv_begin(char *, char *, dmu_replay_record_t *,
boolean_t, boolean_t, nvlist_t *, nvlist_t *, char *,
dmu_recv_cookie_t *, zfs_file_t *, offset_t *);
int dmu_recv_stream(dmu_recv_cookie_t *, offset_t *);
int dmu_recv_end(dmu_recv_cookie_t *, void *);
boolean_t dmu_objset_is_receiving(objset_t *);
#endif /* _DMU_RECV_H */