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freebsd-skq/sys/security/audit/audit_private.h
Robert Watson 2ddefb6d5d Rework the logic around quick checks for auditing that take place at 
system-call entry and whenever audit arguments or return values are
captured:

1. Expose a single global, audit_syscalls_enabled, which controls
   whether the audit framework is entered, rather than exposing
   components of the policy -- e.g., if the trail is enabled,
   suspended, etc.

2. Introduce a new function audit_syscalls_enabled_update(), which is
   called to update audit_syscalls_enabled whenever an aspect of the
   policy changes, so that the value can be updated.

3. Remove a check of trail enablement/suspension from audit_new() --
   at the point where this function has been entered, we believe that
   system-call auditing is already in force, or we wouldn't get here,
   so simply proceed to more expensive policy checks.

4. Use an audit-provided global, audit_dtrace_enabled, rather than a
   dtaudit-provided global, to provide policy indicating whether
   dtaudit would like system calls to be audited.

5. Do some minor cosmetic renaming to clarify what various variables
   are for.

These changes collectively arrange it so that traditional audit
(trail, pipes) or the DTrace audit provider can enable system-call
probes without the other configured.  Otherwise, dtaudit cannot
capture system-call data without auditd(8) started.

Reviewed by:		gnn
Sponsored by:		DARPA, AFRL
Approved by:		re (gjb)
Differential Revision:	https://reviews.freebsd.org/D17348
2018-10-02 15:58:17 +00:00

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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1999-2009 Apple Inc.
* Copyright (c) 2016, 2018 Robert N. M. Watson
* All rights reserved.
*
* Portions of this software were developed by BAE Systems, the University of
* Cambridge Computer Laboratory, and Memorial University under DARPA/AFRL
* contract FA8650-15-C-7558 ("CADETS"), as part of the DARPA Transparent
* Computing (TC) research program.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Apple Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
/*
* This include file contains function prototypes and type definitions used
* within the audit implementation.
*/
#ifndef _SECURITY_AUDIT_PRIVATE_H_
#define _SECURITY_AUDIT_PRIVATE_H_
#ifndef _KERNEL
#error "no user-serviceable parts inside"
#endif
#include <sys/caprights.h>
#include <sys/ipc.h>
#include <sys/socket.h>
#include <sys/ucred.h>
#ifdef MALLOC_DECLARE
MALLOC_DECLARE(M_AUDITBSM);
MALLOC_DECLARE(M_AUDITDATA);
MALLOC_DECLARE(M_AUDITPATH);
MALLOC_DECLARE(M_AUDITTEXT);
MALLOC_DECLARE(M_AUDITGIDSET);
#endif
/*
* Audit control variables that are usually set/read via system calls and
* used to control various aspects of auditing.
*/
extern struct au_qctrl audit_qctrl;
extern struct audit_fstat audit_fstat;
extern struct au_mask audit_nae_mask;
extern int audit_panic_on_write_fail;
extern int audit_fail_stop;
extern int audit_argv;
extern int audit_arge;
/*
* Success/failure conditions for the conversion of a kernel audit record to
* BSM format.
*/
#define BSM_SUCCESS 0
#define BSM_FAILURE 1
#define BSM_NOAUDIT 2
/*
* Defines for the kernel audit record k_ar_commit field. Flags are set to
* indicate what sort of record it is, and which preselection mechanism
* selected it.
*/
#define AR_COMMIT_KERNEL 0x00000001U
#define AR_COMMIT_USER 0x00000010U
#define AR_PRESELECT_TRAIL 0x00001000U
#define AR_PRESELECT_PIPE 0x00002000U
#define AR_PRESELECT_USER_TRAIL 0x00004000U
#define AR_PRESELECT_USER_PIPE 0x00008000U
#define AR_PRESELECT_DTRACE 0x00010000U
/*
* Audit data is generated as a stream of struct audit_record structures,
* linked by struct kaudit_record, and contain storage for possible audit so
* that it will not need to be allocated during the processing of a system
* call, both improving efficiency and avoiding sleeping at untimely moments.
* This structure is converted to BSM format before being written to disk.
*/
struct vnode_au_info {
mode_t vn_mode;
uid_t vn_uid;
gid_t vn_gid;
u_int32_t vn_dev; /* XXX dev_t compatibility */
long vn_fsid; /* XXX uint64_t compatibility */
long vn_fileid; /* XXX ino_t compatibility */
long vn_gen;
};
struct groupset {
gid_t *gidset;
u_int gidset_size;
};
struct socket_au_info {
int so_domain;
int so_type;
int so_protocol;
in_addr_t so_raddr; /* Remote address if INET socket. */
in_addr_t so_laddr; /* Local address if INET socket. */
u_short so_rport; /* Remote port. */
u_short so_lport; /* Local port. */
};
/*
* The following is used for A_OLDSETQCTRL and AU_OLDGETQCTRL and a 64-bit
* userland.
*/
struct au_qctrl64 {
u_int64_t aq64_hiwater;
u_int64_t aq64_lowater;
u_int64_t aq64_bufsz;
u_int64_t aq64_delay;
u_int64_t aq64_minfree;
};
typedef struct au_qctrl64 au_qctrl64_t;
union auditon_udata {
char *au_path;
int au_cond;
int au_flags;
int au_policy;
int au_trigger;
int64_t au_cond64;
int64_t au_policy64;
au_evclass_map_t au_evclass;
au_mask_t au_mask;
auditinfo_t au_auinfo;
auditpinfo_t au_aupinfo;
auditpinfo_addr_t au_aupinfo_addr;
au_qctrl_t au_qctrl;
au_qctrl64_t au_qctrl64;
au_stat_t au_stat;
au_fstat_t au_fstat;
auditinfo_addr_t au_kau_info;
au_evname_map_t au_evname;
};
struct posix_ipc_perm {
uid_t pipc_uid;
gid_t pipc_gid;
mode_t pipc_mode;
};
struct audit_record {
/* Audit record header. */
u_int32_t ar_magic;
int ar_event;
int ar_retval; /* value returned to the process */
int ar_errno; /* return status of system call */
struct timespec ar_starttime;
struct timespec ar_endtime;
u_int64_t ar_valid_arg; /* Bitmask of valid arguments */
/* Audit subject information. */
struct xucred ar_subj_cred;
uid_t ar_subj_ruid;
gid_t ar_subj_rgid;
gid_t ar_subj_egid;
uid_t ar_subj_auid; /* Audit user ID */
pid_t ar_subj_asid; /* Audit session ID */
pid_t ar_subj_pid;
struct au_tid ar_subj_term;
struct au_tid_addr ar_subj_term_addr;
struct au_mask ar_subj_amask;
/* Operation arguments. */
uid_t ar_arg_euid;
uid_t ar_arg_ruid;
uid_t ar_arg_suid;
gid_t ar_arg_egid;
gid_t ar_arg_rgid;
gid_t ar_arg_sgid;
pid_t ar_arg_pid;
pid_t ar_arg_asid;
struct au_tid ar_arg_termid;
struct au_tid_addr ar_arg_termid_addr;
uid_t ar_arg_uid;
uid_t ar_arg_auid;
gid_t ar_arg_gid;
struct groupset ar_arg_groups;
int ar_arg_fd;
int ar_arg_atfd1;
int ar_arg_atfd2;
int ar_arg_fflags;
mode_t ar_arg_mode;
int ar_arg_dev; /* XXX dev_t compatibility */
long ar_arg_value;
void *ar_arg_addr;
int ar_arg_len;
int ar_arg_mask;
u_int ar_arg_signum;
char ar_arg_login[MAXLOGNAME];
int ar_arg_ctlname[CTL_MAXNAME];
struct socket_au_info ar_arg_sockinfo;
char *ar_arg_upath1;
char *ar_arg_upath2;
char *ar_arg_text;
struct au_mask ar_arg_amask;
struct vnode_au_info ar_arg_vnode1;
struct vnode_au_info ar_arg_vnode2;
int ar_arg_cmd;
int ar_arg_svipc_which;
int ar_arg_svipc_cmd;
struct ipc_perm ar_arg_svipc_perm;
int ar_arg_svipc_id;
void *ar_arg_svipc_addr;
struct posix_ipc_perm ar_arg_pipc_perm;
union auditon_udata ar_arg_auditon;
char *ar_arg_argv;
int ar_arg_argc;
char *ar_arg_envv;
int ar_arg_envc;
int ar_arg_exitstatus;
int ar_arg_exitretval;
struct sockaddr_storage ar_arg_sockaddr;
cap_rights_t ar_arg_rights;
uint32_t ar_arg_fcntl_rights;
char ar_jailname[MAXHOSTNAMELEN];
};
/*
* Arguments in the audit record are initially not defined; flags are set to
* indicate if they are present so they can be included in the audit log
* stream only if defined.
*/
#define ARG_EUID 0x0000000000000001ULL
#define ARG_RUID 0x0000000000000002ULL
#define ARG_SUID 0x0000000000000004ULL
#define ARG_EGID 0x0000000000000008ULL
#define ARG_RGID 0x0000000000000010ULL
#define ARG_SGID 0x0000000000000020ULL
#define ARG_PID 0x0000000000000040ULL
#define ARG_UID 0x0000000000000080ULL
#define ARG_AUID 0x0000000000000100ULL
#define ARG_GID 0x0000000000000200ULL
#define ARG_FD 0x0000000000000400ULL
#define ARG_POSIX_IPC_PERM 0x0000000000000800ULL
#define ARG_FFLAGS 0x0000000000001000ULL
#define ARG_MODE 0x0000000000002000ULL
#define ARG_DEV 0x0000000000004000ULL
#define ARG_ADDR 0x0000000000008000ULL
#define ARG_LEN 0x0000000000010000ULL
#define ARG_MASK 0x0000000000020000ULL
#define ARG_SIGNUM 0x0000000000040000ULL
#define ARG_LOGIN 0x0000000000080000ULL
#define ARG_SADDRINET 0x0000000000100000ULL
#define ARG_SADDRINET6 0x0000000000200000ULL
#define ARG_SADDRUNIX 0x0000000000400000ULL
#define ARG_TERMID_ADDR 0x0000000000800000ULL
#define ARG_UNUSED2 0x0000000001000000ULL
#define ARG_UPATH1 0x0000000002000000ULL
#define ARG_UPATH2 0x0000000004000000ULL
#define ARG_TEXT 0x0000000008000000ULL
#define ARG_VNODE1 0x0000000010000000ULL
#define ARG_VNODE2 0x0000000020000000ULL
#define ARG_SVIPC_CMD 0x0000000040000000ULL
#define ARG_SVIPC_PERM 0x0000000080000000ULL
#define ARG_SVIPC_ID 0x0000000100000000ULL
#define ARG_SVIPC_ADDR 0x0000000200000000ULL
#define ARG_GROUPSET 0x0000000400000000ULL
#define ARG_CMD 0x0000000800000000ULL
#define ARG_SOCKINFO 0x0000001000000000ULL
#define ARG_ASID 0x0000002000000000ULL
#define ARG_TERMID 0x0000004000000000ULL
#define ARG_AUDITON 0x0000008000000000ULL
#define ARG_VALUE 0x0000010000000000ULL
#define ARG_AMASK 0x0000020000000000ULL
#define ARG_CTLNAME 0x0000040000000000ULL
#define ARG_PROCESS 0x0000080000000000ULL
#define ARG_MACHPORT1 0x0000100000000000ULL
#define ARG_MACHPORT2 0x0000200000000000ULL
#define ARG_EXIT 0x0000400000000000ULL
#define ARG_IOVECSTR 0x0000800000000000ULL
#define ARG_ARGV 0x0001000000000000ULL
#define ARG_ENVV 0x0002000000000000ULL
#define ARG_ATFD1 0x0004000000000000ULL
#define ARG_ATFD2 0x0008000000000000ULL
#define ARG_RIGHTS 0x0010000000000000ULL
#define ARG_FCNTL_RIGHTS 0x0020000000000000ULL
#define ARG_SVIPC_WHICH 0x0200000000000000ULL
#define ARG_NONE 0x0000000000000000ULL
#define ARG_ALL 0xFFFFFFFFFFFFFFFFULL
#define ARG_IS_VALID(kar, arg) ((kar)->k_ar.ar_valid_arg & (arg))
#define ARG_SET_VALID(kar, arg) do { \
(kar)->k_ar.ar_valid_arg |= (arg); \
} while (0)
#define ARG_CLEAR_VALID(kar, arg) do { \
(kar)->k_ar.ar_valid_arg &= ~(arg); \
} while (0)
/*
* In-kernel version of audit record; the basic record plus queue meta-data.
* This record can also have a pointer set to some opaque data that will be
* passed through to the audit writing mechanism.
*/
struct kaudit_record {
struct audit_record k_ar;
u_int32_t k_ar_commit;
void *k_udata; /* User data. */
u_int k_ulen; /* User data length. */
struct uthread *k_uthread; /* Audited thread. */
void *k_dtaudit_state;
TAILQ_ENTRY(kaudit_record) k_q;
};
TAILQ_HEAD(kaudit_queue, kaudit_record);
/*
* Functions to manage the allocation, release, and commit of kernel audit
* records.
*/
void audit_abort(struct kaudit_record *ar);
void audit_commit(struct kaudit_record *ar, int error,
int retval);
struct kaudit_record *audit_new(int event, struct thread *td);
/*
* Function to update the audit_syscalls_enabled flag, whose value is affected
* by configuration of the audit trail/pipe mechanism and DTrace. Call this
* function when any of the inputs to that policy change.
*/
void audit_syscalls_enabled_update(void);
/*
* Functions relating to the conversion of internal kernel audit records to
* the BSM file format.
*/
struct au_record;
int kaudit_to_bsm(struct kaudit_record *kar, struct au_record **pau);
int bsm_rec_verify(void *rec);
/*
* Kernel versions of the libbsm audit record functions.
*/
void kau_free(struct au_record *rec);
void kau_init(void);
/*
* Return values for pre-selection and post-selection decisions.
*/
#define AU_PRS_SUCCESS 1
#define AU_PRS_FAILURE 2
#define AU_PRS_BOTH (AU_PRS_SUCCESS|AU_PRS_FAILURE)
/*
* Data structures relating to the kernel audit queue. Ideally, these might
* be abstracted so that only accessor methods are exposed.
*/
extern struct mtx audit_mtx;
extern struct cv audit_watermark_cv;
extern struct cv audit_worker_cv;
extern struct kaudit_queue audit_q;
extern int audit_q_len;
extern int audit_pre_q_len;
extern int audit_in_failure;
/*
* Flags to use on audit files when opening and closing.
*/
#define AUDIT_OPEN_FLAGS (FWRITE | O_APPEND)
#define AUDIT_CLOSE_FLAGS (FWRITE | O_APPEND)
/*
* Audit event-to-name mapping structure, maintained in audit_bsm_klib.c. It
* appears in this header so that the DTrace audit provider can dereference
* instances passed back in the au_evname_foreach() callbacks. Safe access to
* its fields requires holding ene_lock (after it is visible in the global
* table).
*
* Locking:
* (c) - Constant after inserted in the global table
* (l) - Protected by ene_lock
* (m) - Protected by evnamemap_lock (audit_bsm_klib.c)
* (M) - Writes protected by evnamemap_lock; reads unprotected.
*/
struct evname_elem {
au_event_t ene_event; /* (c) */
char ene_name[EVNAMEMAP_NAME_SIZE]; /* (l) */
LIST_ENTRY(evname_elem) ene_entry; /* (m) */
struct mtx ene_lock;
/* DTrace probe IDs; 0 if not yet registered. */
uint32_t ene_commit_probe_id; /* (M) */
uint32_t ene_bsm_probe_id; /* (M) */
/* Flags indicating if the probes enabled or not. */
int ene_commit_probe_enabled; /* (M) */
int ene_bsm_probe_enabled; /* (M) */
};
#define EVNAME_LOCK(ene) mtx_lock(&(ene)->ene_lock)
#define EVNAME_UNLOCK(ene) mtx_unlock(&(ene)->ene_lock)
/*
* Callback function typedef for the same.
*/
typedef void (*au_evnamemap_callback_t)(struct evname_elem *ene);
/*
* DTrace audit provider (dtaudit) hooks -- to be set non-NULL when the audit
* provider is loaded and ready to be called into.
*/
extern void *(*dtaudit_hook_preselect)(au_id_t auid, au_event_t event,
au_class_t class);
extern int (*dtaudit_hook_commit)(struct kaudit_record *kar,
au_id_t auid, au_event_t event, au_class_t class,
int sorf);
extern void (*dtaudit_hook_bsm)(struct kaudit_record *kar, au_id_t auid,
au_event_t event, au_class_t class, int sorf,
void *bsm_data, size_t bsm_len);
#include <sys/fcntl.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
/*
* Some of the BSM tokenizer functions take different parameters in the
* kernel implementations in order to save the copying of large kernel data
* structures. The prototypes of these functions are declared here.
*/
token_t *kau_to_socket(struct socket_au_info *soi);
/*
* audit_klib prototypes
*/
int au_preselect(au_event_t event, au_class_t class,
au_mask_t *mask_p, int sorf);
void au_evclassmap_init(void);
void au_evclassmap_insert(au_event_t event, au_class_t class);
au_class_t au_event_class(au_event_t event);
void au_evnamemap_init(void);
void au_evnamemap_insert(au_event_t event, const char *name);
void au_evnamemap_foreach(au_evnamemap_callback_t callback);
struct evname_elem *au_evnamemap_lookup(au_event_t event);
int au_event_name(au_event_t event, char *name);
au_event_t audit_ctlname_to_sysctlevent(int name[], uint64_t valid_arg);
au_event_t audit_flags_and_error_to_openevent(int oflags, int error);
au_event_t audit_flags_and_error_to_openatevent(int oflags, int error);
au_event_t audit_msgctl_to_event(int cmd);
au_event_t audit_msgsys_to_event(int which);
au_event_t audit_semctl_to_event(int cmd);
au_event_t audit_semsys_to_event(int which);
au_event_t audit_shmsys_to_event(int which);
void audit_canon_path(struct thread *td, int dirfd, char *path,
char *cpath);
au_event_t auditon_command_event(int cmd);
/*
* Audit trigger events notify user space of kernel audit conditions
* asynchronously.
*/
void audit_trigger_init(void);
int audit_send_trigger(unsigned int trigger);
/*
* Accessor functions to manage global audit state.
*/
void audit_set_kinfo(struct auditinfo_addr *);
void audit_get_kinfo(struct auditinfo_addr *);
/*
* General audit related functions.
*/
struct kaudit_record *currecord(void);
void audit_free(struct kaudit_record *ar);
void audit_shutdown(void *arg, int howto);
void audit_rotate_vnode(struct ucred *cred,
struct vnode *vp);
void audit_worker_init(void);
/*
* Audit pipe functions.
*/
int audit_pipe_preselect(au_id_t auid, au_event_t event,
au_class_t class, int sorf, int trail_select);
void audit_pipe_submit(au_id_t auid, au_event_t event, au_class_t class,
int sorf, int trail_select, void *record, u_int record_len);
void audit_pipe_submit_user(void *record, u_int record_len);
#endif /* ! _SECURITY_AUDIT_PRIVATE_H_ */
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