freebsd-skq/sys/security/audit/audit_syscalls.c
Christian S.J. Peron 06399e90bc Mark the audit system calls as being un-implemented in jails. Currently we do
not trust jails enough to execute audit related system calls. An example of
this is with su(1), or login(1) within prisons. So, if the syscall request
comes from a jail return ENOSYS. This will cause these utilities to operate
as if audit is not present in the kernel.

Looking forward, this problem will be remedied by allowing non privileged
users to maintain and their own audit streams, but the details on exactly how
this will be implemented needs to be worked out.

This change should fix situations when options AUDIT has been compiled into
the kernel, and utilities like su(1), or login(1) fail due to audit system
call failures within jails.

This is a RELENG_6 candidate.

Reported by:	Christian Brueffer
Discussed with:	rwatson
MFC after:	3 days
2006-10-10 15:49:10 +00:00

691 lines
14 KiB
C

/*
* Copyright (c) 1999-2005 Apple Computer, Inc.
* All rights reserved.
*
* 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 Computer, 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.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/proc.h>
#include <sys/sysproto.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <sys/jail.h>
#include <bsm/audit.h>
#include <bsm/audit_kevents.h>
#include <security/audit/audit.h>
#include <security/audit/audit_private.h>
#ifdef AUDIT
/*
* MPSAFE
*
* System call to allow a user space application to submit a BSM audit record
* to the kernel for inclusion in the audit log. This function does little
* verification on the audit record that is submitted.
*
* XXXAUDIT: Audit preselection for user records does not currently work,
* since we pre-select only based on the AUE_audit event type, not the event
* type submitted as part of the user audit data.
*/
/* ARGSUSED */
int
audit(struct thread *td, struct audit_args *uap)
{
int error;
void * rec;
struct kaudit_record *ar;
if (jailed(td->td_ucred))
return (ENOSYS);
error = suser(td);
if (error)
return (error);
if ((uap->length <= 0) || (uap->length > audit_qctrl.aq_bufsz))
return (EINVAL);
ar = currecord();
/*
* If there's no current audit record (audit() itself not audited)
* commit the user audit record.
*/
if (ar == NULL) {
/*
* This is not very efficient; we're required to allocate a
* complete kernel audit record just so the user record can
* tag along.
*
* XXXAUDIT: Maybe AUE_AUDIT in the system call context and
* special pre-select handling?
*/
td->td_ar = audit_new(AUE_NULL, td);
if (td->td_ar == NULL)
return (ENOTSUP);
ar = td->td_ar;
}
if (uap->length > MAX_AUDIT_RECORD_SIZE)
return (EINVAL);
rec = malloc(uap->length, M_AUDITDATA, M_WAITOK);
error = copyin(uap->record, rec, uap->length);
if (error)
goto free_out;
/* Verify the record. */
if (bsm_rec_verify(rec) == 0) {
error = EINVAL;
goto free_out;
}
/*
* Attach the user audit record to the kernel audit record. Because
* this system call is an auditable event, we will write the user
* record along with the record for this audit event.
*
* XXXAUDIT: KASSERT appropriate starting values of k_udata, k_ulen,
* k_ar_commit & AR_COMMIT_USER?
*/
ar->k_udata = rec;
ar->k_ulen = uap->length;
ar->k_ar_commit |= AR_COMMIT_USER;
/*
* Currently we assume that all preselection has been performed in
* userspace. We unconditionally set these masks so that the records
* get committed both to the trail and pipe. In the future we will
* want to setup kernel based preselection.
*/
ar->k_ar_commit |= (AR_PRESELECT_USER_TRAIL | AR_PRESELECT_USER_PIPE);
return (0);
free_out:
/*
* audit_syscall_exit() will free the audit record on the thread even
* if we allocated it above.
*/
free(rec, M_AUDITDATA);
return (error);
}
/*
* MPSAFE
*
* System call to manipulate auditing.
*/
/* ARGSUSED */
int
auditon(struct thread *td, struct auditon_args *uap)
{
int error;
union auditon_udata udata;
struct proc *tp;
if (jailed(td->td_ucred))
return (ENOSYS);
AUDIT_ARG(cmd, uap->cmd);
error = suser(td);
if (error)
return (error);
if ((uap->length <= 0) || (uap->length > sizeof(union auditon_udata)))
return (EINVAL);
memset((void *)&udata, 0, sizeof(udata));
/*
* Some of the GET commands use the arguments too.
*/
switch (uap->cmd) {
case A_SETPOLICY:
case A_SETKMASK:
case A_SETQCTRL:
case A_SETSTAT:
case A_SETUMASK:
case A_SETSMASK:
case A_SETCOND:
case A_SETCLASS:
case A_SETPMASK:
case A_SETFSIZE:
case A_SETKAUDIT:
case A_GETCLASS:
case A_GETPINFO:
case A_GETPINFO_ADDR:
case A_SENDTRIGGER:
error = copyin(uap->data, (void *)&udata, uap->length);
if (error)
return (error);
AUDIT_ARG(auditon, &udata);
break;
}
/*
* XXX Need to implement these commands by accessing the global
* values associated with the commands.
*
* XXXAUDIT: Locking?
*/
switch (uap->cmd) {
case A_GETPOLICY:
if (!audit_fail_stop)
udata.au_policy |= AUDIT_CNT;
if (audit_panic_on_write_fail)
udata.au_policy |= AUDIT_AHLT;
if (audit_argv)
udata.au_policy |= AUDIT_ARGV;
if (audit_arge)
udata.au_policy |= AUDIT_ARGE;
break;
case A_SETPOLICY:
if (udata.au_policy & ~(AUDIT_CNT|AUDIT_AHLT|AUDIT_ARGV|
AUDIT_ARGE))
return (EINVAL);
/*
* XXX - Need to wake up waiters if the policy relaxes?
*/
audit_fail_stop = ((udata.au_policy & AUDIT_CNT) == 0);
audit_panic_on_write_fail = (udata.au_policy & AUDIT_AHLT);
audit_argv = (udata.au_policy & AUDIT_ARGV);
audit_arge = (udata.au_policy & AUDIT_ARGE);
break;
case A_GETKMASK:
udata.au_mask = audit_nae_mask;
break;
case A_SETKMASK:
audit_nae_mask = udata.au_mask;
break;
case A_GETQCTRL:
udata.au_qctrl = audit_qctrl;
break;
case A_SETQCTRL:
if ((udata.au_qctrl.aq_hiwater > AQ_MAXHIGH) ||
(udata.au_qctrl.aq_lowater >= udata.au_qctrl.aq_hiwater) ||
(udata.au_qctrl.aq_bufsz > AQ_MAXBUFSZ) ||
(udata.au_qctrl.aq_minfree < 0) ||
(udata.au_qctrl.aq_minfree > 100))
return (EINVAL);
audit_qctrl = udata.au_qctrl;
/* XXX The queue delay value isn't used with the kernel. */
audit_qctrl.aq_delay = -1;
break;
case A_GETCWD:
return (ENOSYS);
break;
case A_GETCAR:
return (ENOSYS);
break;
case A_GETSTAT:
return (ENOSYS);
break;
case A_SETSTAT:
return (ENOSYS);
break;
case A_SETUMASK:
return (ENOSYS);
break;
case A_SETSMASK:
return (ENOSYS);
break;
case A_GETCOND:
if (audit_enabled && !audit_suspended)
udata.au_cond = AUC_AUDITING;
else
udata.au_cond = AUC_NOAUDIT;
break;
case A_SETCOND:
if (udata.au_cond == AUC_NOAUDIT)
audit_suspended = 1;
if (udata.au_cond == AUC_AUDITING)
audit_suspended = 0;
if (udata.au_cond == AUC_DISABLED) {
audit_suspended = 1;
audit_shutdown(NULL, 0);
}
break;
case A_GETCLASS:
udata.au_evclass.ec_class = au_event_class(
udata.au_evclass.ec_number);
break;
case A_SETCLASS:
au_evclassmap_insert(udata.au_evclass.ec_number,
udata.au_evclass.ec_class);
break;
case A_GETPINFO:
if (udata.au_aupinfo.ap_pid < 1)
return (EINVAL);
/* XXXAUDIT: p_cansee()? */
if ((tp = pfind(udata.au_aupinfo.ap_pid)) == NULL)
return (EINVAL);
udata.au_aupinfo.ap_auid = tp->p_au->ai_auid;
udata.au_aupinfo.ap_mask.am_success =
tp->p_au->ai_mask.am_success;
udata.au_aupinfo.ap_mask.am_failure =
tp->p_au->ai_mask.am_failure;
udata.au_aupinfo.ap_termid.machine =
tp->p_au->ai_termid.machine;
udata.au_aupinfo.ap_termid.port = tp->p_au->ai_termid.port;
udata.au_aupinfo.ap_asid = tp->p_au->ai_asid;
PROC_UNLOCK(tp);
break;
case A_SETPMASK:
if (udata.au_aupinfo.ap_pid < 1)
return (EINVAL);
/* XXXAUDIT: p_cansee()? */
if ((tp = pfind(udata.au_aupinfo.ap_pid)) == NULL)
return (EINVAL);
tp->p_au->ai_mask.am_success =
udata.au_aupinfo.ap_mask.am_success;
tp->p_au->ai_mask.am_failure =
udata.au_aupinfo.ap_mask.am_failure;
PROC_UNLOCK(tp);
break;
case A_SETFSIZE:
if ((udata.au_fstat.af_filesz != 0) &&
(udata.au_fstat.af_filesz < MIN_AUDIT_FILE_SIZE))
return (EINVAL);
audit_fstat.af_filesz = udata.au_fstat.af_filesz;
break;
case A_GETFSIZE:
udata.au_fstat.af_filesz = audit_fstat.af_filesz;
udata.au_fstat.af_currsz = audit_fstat.af_currsz;
break;
case A_GETPINFO_ADDR:
return (ENOSYS);
break;
case A_GETKAUDIT:
return (ENOSYS);
break;
case A_SETKAUDIT:
return (ENOSYS);
break;
case A_SENDTRIGGER:
if ((udata.au_trigger < AUDIT_TRIGGER_MIN) ||
(udata.au_trigger > AUDIT_TRIGGER_MAX))
return (EINVAL);
return (send_trigger(udata.au_trigger));
}
/*
* Copy data back to userspace for the GET comands.
*/
switch (uap->cmd) {
case A_GETPOLICY:
case A_GETKMASK:
case A_GETQCTRL:
case A_GETCWD:
case A_GETCAR:
case A_GETSTAT:
case A_GETCOND:
case A_GETCLASS:
case A_GETPINFO:
case A_GETFSIZE:
case A_GETPINFO_ADDR:
case A_GETKAUDIT:
error = copyout((void *)&udata, uap->data, uap->length);
if (error)
return (error);
break;
}
return (0);
}
/*
* MPSAFE
*
* System calls to manage the user audit information.
*/
/* ARGSUSED */
int
getauid(struct thread *td, struct getauid_args *uap)
{
int error;
au_id_t id;
if (jailed(td->td_ucred))
return (ENOSYS);
error = suser(td);
if (error)
return (error);
/*
* XXX: Integer read on static pointer dereference: doesn't need
* locking?
*/
PROC_LOCK(td->td_proc);
id = td->td_proc->p_au->ai_auid;
PROC_UNLOCK(td->td_proc);
return copyout(&id, uap->auid, sizeof(id));
}
/* MPSAFE */
/* ARGSUSED */
int
setauid(struct thread *td, struct setauid_args *uap)
{
int error;
au_id_t id;
if (jailed(td->td_ucred))
return (ENOSYS);
error = suser(td);
if (error)
return (error);
error = copyin(uap->auid, &id, sizeof(id));
if (error)
return (error);
audit_arg_auid(id);
/*
* XXX: Integer write on static pointer dereference: doesn't need
* locking?
*
* XXXAUDIT: Might need locking to serialize audit events in the same
* order as change events? Or maybe that's an under-solveable
* problem.
*
* XXXRW: Test privilege while holding the proc lock?
*/
PROC_LOCK(td->td_proc);
td->td_proc->p_au->ai_auid = id;
PROC_UNLOCK(td->td_proc);
return (0);
}
/*
* MPSAFE
* System calls to get and set process audit information.
*/
/* ARGSUSED */
int
getaudit(struct thread *td, struct getaudit_args *uap)
{
struct auditinfo ai;
int error;
if (jailed(td->td_ucred))
return (ENOSYS);
error = suser(td);
if (error)
return (error);
PROC_LOCK(td->td_proc);
ai = *td->td_proc->p_au;
PROC_UNLOCK(td->td_proc);
return (copyout(&ai, uap->auditinfo, sizeof(ai)));
}
/* MPSAFE */
/* ARGSUSED */
int
setaudit(struct thread *td, struct setaudit_args *uap)
{
struct auditinfo ai;
int error;
if (jailed(td->td_ucred))
return (ENOSYS);
error = suser(td);
if (error)
return (error);
error = copyin(uap->auditinfo, &ai, sizeof(ai));
if (error)
return (error);
audit_arg_auditinfo(&ai);
/*
* XXXRW: Test privilege while holding the proc lock?
*/
PROC_LOCK(td->td_proc);
*td->td_proc->p_au = ai;
PROC_UNLOCK(td->td_proc);
return (0);
}
/* MPSAFE */
/* ARGSUSED */
int
getaudit_addr(struct thread *td, struct getaudit_addr_args *uap)
{
int error;
if (jailed(td->td_ucred))
return (ENOSYS);
error = suser(td);
if (error)
return (error);
return (ENOSYS);
}
/* MPSAFE */
/* ARGSUSED */
int
setaudit_addr(struct thread *td, struct setaudit_addr_args *uap)
{
int error;
if (jailed(td->td_ucred))
return (ENOSYS);
error = suser(td);
if (error)
return (error);
return (ENOSYS);
}
/*
* MPSAFE
* Syscall to manage audit files.
*
* XXX: Should generate an audit event.
*/
/* ARGSUSED */
int
auditctl(struct thread *td, struct auditctl_args *uap)
{
struct nameidata nd;
struct ucred *cred;
struct vnode *vp;
int error = 0;
int flags, vfslocked;
if (jailed(td->td_ucred))
return (ENOSYS);
error = suser(td);
if (error)
return (error);
vp = NULL;
cred = NULL;
/*
* If a path is specified, open the replacement vnode, perform
* validity checks, and grab another reference to the current
* credential.
*
* XXXAUDIT: On Darwin, a NULL path is used to disable audit.
*/
if (uap->path == NULL)
return (EINVAL);
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | MPSAFE | AUDITVNODE1,
UIO_USERSPACE, uap->path, td);
flags = AUDIT_OPEN_FLAGS;
error = vn_open(&nd, &flags, 0, -1);
if (error)
return (error);
vfslocked = NDHASGIANT(&nd);
vp = nd.ni_vp;
VOP_UNLOCK(vp, 0, td);
NDFREE(&nd, NDF_ONLY_PNBUF);
if (vp->v_type != VREG) {
vn_close(vp, AUDIT_CLOSE_FLAGS, td->td_ucred, td);
VFS_UNLOCK_GIANT(vfslocked);
return (EINVAL);
}
VFS_UNLOCK_GIANT(vfslocked);
cred = td->td_ucred;
crhold(cred);
/*
* XXXAUDIT: Should audit_suspended actually be cleared by
* audit_worker?
*/
audit_suspended = 0;
audit_rotate_vnode(cred, vp);
return (error);
}
#else /* !AUDIT */
int
audit(struct thread *td, struct audit_args *uap)
{
return (ENOSYS);
}
int
auditon(struct thread *td, struct auditon_args *uap)
{
return (ENOSYS);
}
int
getauid(struct thread *td, struct getauid_args *uap)
{
return (ENOSYS);
}
int
setauid(struct thread *td, struct setauid_args *uap)
{
return (ENOSYS);
}
int
getaudit(struct thread *td, struct getaudit_args *uap)
{
return (ENOSYS);
}
int
setaudit(struct thread *td, struct setaudit_args *uap)
{
return (ENOSYS);
}
int
getaudit_addr(struct thread *td, struct getaudit_addr_args *uap)
{
return (ENOSYS);
}
int
setaudit_addr(struct thread *td, struct setaudit_addr_args *uap)
{
return (ENOSYS);
}
int
auditctl(struct thread *td, struct auditctl_args *uap)
{
return (ENOSYS);
}
void
audit_proc_init(struct proc *p)
{
}
void
audit_proc_fork(struct proc *parent, struct proc *child)
{
}
void
audit_proc_free(struct proc *p)
{
}
#endif /* AUDIT */