freebsd-dev/sys/security/audit/audit_arg.c
Brooks Davis 412f9500e2 Replace the static NGROUPS=NGROUPS_MAX+1=1024 with a dynamic
kern.ngroups+1.  kern.ngroups can range from NGROUPS_MAX=1023 to
INT_MAX-1.  Given that the Windows group limit is 1024, this range
should be sufficient for most applications.

MFC after:	1 month
2010-01-12 07:49:34 +00:00

900 lines
18 KiB
C

/*-
* Copyright (c) 1999-2005 Apple 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 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/filedesc.h>
#include <sys/ipc.h>
#include <sys/mount.h>
#include <sys/proc.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/protosw.h>
#include <sys/domain.h>
#include <sys/sbuf.h>
#include <sys/systm.h>
#include <sys/un.h>
#include <sys/vnode.h>
#include <netinet/in.h>
#include <netinet/in_pcb.h>
#include <security/audit/audit.h>
#include <security/audit/audit_private.h>
/*
* Calls to manipulate elements of the audit record structure from system
* call code. Macro wrappers will prevent this functions from being entered
* if auditing is disabled, avoiding the function call cost. We check the
* thread audit record pointer anyway, as the audit condition could change,
* and pre-selection may not have allocated an audit record for this event.
*
* XXXAUDIT: Should we assert, in each case, that this field of the record
* hasn't already been filled in?
*/
void
audit_arg_addr(void *addr)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_addr = addr;
ARG_SET_VALID(ar, ARG_ADDR);
}
void
audit_arg_exit(int status, int retval)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_exitstatus = status;
ar->k_ar.ar_arg_exitretval = retval;
ARG_SET_VALID(ar, ARG_EXIT);
}
void
audit_arg_len(int len)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_len = len;
ARG_SET_VALID(ar, ARG_LEN);
}
void
audit_arg_atfd1(int atfd)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_atfd1 = atfd;
ARG_SET_VALID(ar, ARG_ATFD1);
}
void
audit_arg_atfd2(int atfd)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_atfd2 = atfd;
ARG_SET_VALID(ar, ARG_ATFD2);
}
void
audit_arg_fd(int fd)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_fd = fd;
ARG_SET_VALID(ar, ARG_FD);
}
void
audit_arg_fflags(int fflags)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_fflags = fflags;
ARG_SET_VALID(ar, ARG_FFLAGS);
}
void
audit_arg_gid(gid_t gid)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_gid = gid;
ARG_SET_VALID(ar, ARG_GID);
}
void
audit_arg_uid(uid_t uid)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_uid = uid;
ARG_SET_VALID(ar, ARG_UID);
}
void
audit_arg_egid(gid_t egid)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_egid = egid;
ARG_SET_VALID(ar, ARG_EGID);
}
void
audit_arg_euid(uid_t euid)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_euid = euid;
ARG_SET_VALID(ar, ARG_EUID);
}
void
audit_arg_rgid(gid_t rgid)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_rgid = rgid;
ARG_SET_VALID(ar, ARG_RGID);
}
void
audit_arg_ruid(uid_t ruid)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_ruid = ruid;
ARG_SET_VALID(ar, ARG_RUID);
}
void
audit_arg_sgid(gid_t sgid)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_sgid = sgid;
ARG_SET_VALID(ar, ARG_SGID);
}
void
audit_arg_suid(uid_t suid)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_suid = suid;
ARG_SET_VALID(ar, ARG_SUID);
}
void
audit_arg_groupset(gid_t *gidset, u_int gidset_size)
{
u_int i;
struct kaudit_record *ar;
KASSERT(gidset_size <= ngroups_max + 1,
("audit_arg_groupset: gidset_size > (kern.ngroups + 1)"));
ar = currecord();
if (ar == NULL)
return;
if (ar->k_ar.ar_arg_groups.gidset == NULL)
ar->k_ar.ar_arg_groups.gidset = malloc(
sizeof(gid_t) * gidset_size, M_AUDITGIDSET, M_WAITOK);
for (i = 0; i < gidset_size; i++)
ar->k_ar.ar_arg_groups.gidset[i] = gidset[i];
ar->k_ar.ar_arg_groups.gidset_size = gidset_size;
ARG_SET_VALID(ar, ARG_GROUPSET);
}
void
audit_arg_login(char *login)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
strlcpy(ar->k_ar.ar_arg_login, login, MAXLOGNAME);
ARG_SET_VALID(ar, ARG_LOGIN);
}
void
audit_arg_ctlname(int *name, int namelen)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
bcopy(name, &ar->k_ar.ar_arg_ctlname, namelen * sizeof(int));
ar->k_ar.ar_arg_len = namelen;
ARG_SET_VALID(ar, ARG_CTLNAME | ARG_LEN);
}
void
audit_arg_mask(int mask)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_mask = mask;
ARG_SET_VALID(ar, ARG_MASK);
}
void
audit_arg_mode(mode_t mode)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_mode = mode;
ARG_SET_VALID(ar, ARG_MODE);
}
void
audit_arg_dev(int dev)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_dev = dev;
ARG_SET_VALID(ar, ARG_DEV);
}
void
audit_arg_value(long value)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_value = value;
ARG_SET_VALID(ar, ARG_VALUE);
}
void
audit_arg_owner(uid_t uid, gid_t gid)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_uid = uid;
ar->k_ar.ar_arg_gid = gid;
ARG_SET_VALID(ar, ARG_UID | ARG_GID);
}
void
audit_arg_pid(pid_t pid)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_pid = pid;
ARG_SET_VALID(ar, ARG_PID);
}
void
audit_arg_process(struct proc *p)
{
struct kaudit_record *ar;
struct ucred *cred;
KASSERT(p != NULL, ("audit_arg_process: p == NULL"));
PROC_LOCK_ASSERT(p, MA_OWNED);
ar = currecord();
if (ar == NULL)
return;
cred = p->p_ucred;
ar->k_ar.ar_arg_auid = cred->cr_audit.ai_auid;
ar->k_ar.ar_arg_euid = cred->cr_uid;
ar->k_ar.ar_arg_egid = cred->cr_groups[0];
ar->k_ar.ar_arg_ruid = cred->cr_ruid;
ar->k_ar.ar_arg_rgid = cred->cr_rgid;
ar->k_ar.ar_arg_asid = cred->cr_audit.ai_asid;
ar->k_ar.ar_arg_termid_addr = cred->cr_audit.ai_termid;
ar->k_ar.ar_arg_pid = p->p_pid;
ARG_SET_VALID(ar, ARG_AUID | ARG_EUID | ARG_EGID | ARG_RUID |
ARG_RGID | ARG_ASID | ARG_TERMID_ADDR | ARG_PID | ARG_PROCESS);
}
void
audit_arg_signum(u_int signum)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_signum = signum;
ARG_SET_VALID(ar, ARG_SIGNUM);
}
void
audit_arg_socket(int sodomain, int sotype, int soprotocol)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_sockinfo.so_domain = sodomain;
ar->k_ar.ar_arg_sockinfo.so_type = sotype;
ar->k_ar.ar_arg_sockinfo.so_protocol = soprotocol;
ARG_SET_VALID(ar, ARG_SOCKINFO);
}
void
audit_arg_sockaddr(struct thread *td, struct sockaddr *sa)
{
struct kaudit_record *ar;
KASSERT(td != NULL, ("audit_arg_sockaddr: td == NULL"));
KASSERT(sa != NULL, ("audit_arg_sockaddr: sa == NULL"));
ar = currecord();
if (ar == NULL)
return;
bcopy(sa, &ar->k_ar.ar_arg_sockaddr, sa->sa_len);
switch (sa->sa_family) {
case AF_INET:
ARG_SET_VALID(ar, ARG_SADDRINET);
break;
case AF_INET6:
ARG_SET_VALID(ar, ARG_SADDRINET6);
break;
case AF_UNIX:
audit_arg_upath1(td, ((struct sockaddr_un *)sa)->sun_path);
ARG_SET_VALID(ar, ARG_SADDRUNIX);
break;
/* XXXAUDIT: default:? */
}
}
void
audit_arg_auid(uid_t auid)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_auid = auid;
ARG_SET_VALID(ar, ARG_AUID);
}
void
audit_arg_auditinfo(struct auditinfo *au_info)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_auid = au_info->ai_auid;
ar->k_ar.ar_arg_asid = au_info->ai_asid;
ar->k_ar.ar_arg_amask.am_success = au_info->ai_mask.am_success;
ar->k_ar.ar_arg_amask.am_failure = au_info->ai_mask.am_failure;
ar->k_ar.ar_arg_termid.port = au_info->ai_termid.port;
ar->k_ar.ar_arg_termid.machine = au_info->ai_termid.machine;
ARG_SET_VALID(ar, ARG_AUID | ARG_ASID | ARG_AMASK | ARG_TERMID);
}
void
audit_arg_auditinfo_addr(struct auditinfo_addr *au_info)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_auid = au_info->ai_auid;
ar->k_ar.ar_arg_asid = au_info->ai_asid;
ar->k_ar.ar_arg_amask.am_success = au_info->ai_mask.am_success;
ar->k_ar.ar_arg_amask.am_failure = au_info->ai_mask.am_failure;
ar->k_ar.ar_arg_termid_addr.at_type = au_info->ai_termid.at_type;
ar->k_ar.ar_arg_termid_addr.at_port = au_info->ai_termid.at_port;
ar->k_ar.ar_arg_termid_addr.at_addr[0] = au_info->ai_termid.at_addr[0];
ar->k_ar.ar_arg_termid_addr.at_addr[1] = au_info->ai_termid.at_addr[1];
ar->k_ar.ar_arg_termid_addr.at_addr[2] = au_info->ai_termid.at_addr[2];
ar->k_ar.ar_arg_termid_addr.at_addr[3] = au_info->ai_termid.at_addr[3];
ARG_SET_VALID(ar, ARG_AUID | ARG_ASID | ARG_AMASK | ARG_TERMID_ADDR);
}
void
audit_arg_text(char *text)
{
struct kaudit_record *ar;
KASSERT(text != NULL, ("audit_arg_text: text == NULL"));
ar = currecord();
if (ar == NULL)
return;
/* Invalidate the text string */
ar->k_ar.ar_valid_arg &= (ARG_ALL ^ ARG_TEXT);
if (ar->k_ar.ar_arg_text == NULL)
ar->k_ar.ar_arg_text = malloc(MAXPATHLEN, M_AUDITTEXT,
M_WAITOK);
strncpy(ar->k_ar.ar_arg_text, text, MAXPATHLEN);
ARG_SET_VALID(ar, ARG_TEXT);
}
void
audit_arg_cmd(int cmd)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_cmd = cmd;
ARG_SET_VALID(ar, ARG_CMD);
}
void
audit_arg_svipc_cmd(int cmd)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_svipc_cmd = cmd;
ARG_SET_VALID(ar, ARG_SVIPC_CMD);
}
void
audit_arg_svipc_perm(struct ipc_perm *perm)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
bcopy(perm, &ar->k_ar.ar_arg_svipc_perm,
sizeof(ar->k_ar.ar_arg_svipc_perm));
ARG_SET_VALID(ar, ARG_SVIPC_PERM);
}
void
audit_arg_svipc_id(int id)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_svipc_id = id;
ARG_SET_VALID(ar, ARG_SVIPC_ID);
}
void
audit_arg_svipc_addr(void * addr)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_svipc_addr = addr;
ARG_SET_VALID(ar, ARG_SVIPC_ADDR);
}
void
audit_arg_posix_ipc_perm(uid_t uid, gid_t gid, mode_t mode)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_pipc_perm.pipc_uid = uid;
ar->k_ar.ar_arg_pipc_perm.pipc_gid = gid;
ar->k_ar.ar_arg_pipc_perm.pipc_mode = mode;
ARG_SET_VALID(ar, ARG_POSIX_IPC_PERM);
}
void
audit_arg_auditon(union auditon_udata *udata)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
bcopy((void *)udata, &ar->k_ar.ar_arg_auditon,
sizeof(ar->k_ar.ar_arg_auditon));
ARG_SET_VALID(ar, ARG_AUDITON);
}
/*
* Audit information about a file, either the file's vnode info, or its
* socket address info.
*/
void
audit_arg_file(struct proc *p, struct file *fp)
{
struct kaudit_record *ar;
struct socket *so;
struct inpcb *pcb;
struct vnode *vp;
int vfslocked;
ar = currecord();
if (ar == NULL)
return;
switch (fp->f_type) {
case DTYPE_VNODE:
case DTYPE_FIFO:
/*
* XXXAUDIT: Only possibly to record as first vnode?
*/
vp = fp->f_vnode;
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
vn_lock(vp, LK_SHARED | LK_RETRY);
audit_arg_vnode1(vp);
VOP_UNLOCK(vp, 0);
VFS_UNLOCK_GIANT(vfslocked);
break;
case DTYPE_SOCKET:
so = (struct socket *)fp->f_data;
if (INP_CHECK_SOCKAF(so, PF_INET)) {
SOCK_LOCK(so);
ar->k_ar.ar_arg_sockinfo.so_type =
so->so_type;
ar->k_ar.ar_arg_sockinfo.so_domain =
INP_SOCKAF(so);
ar->k_ar.ar_arg_sockinfo.so_protocol =
so->so_proto->pr_protocol;
SOCK_UNLOCK(so);
pcb = (struct inpcb *)so->so_pcb;
INP_RLOCK(pcb);
ar->k_ar.ar_arg_sockinfo.so_raddr =
pcb->inp_faddr.s_addr;
ar->k_ar.ar_arg_sockinfo.so_laddr =
pcb->inp_laddr.s_addr;
ar->k_ar.ar_arg_sockinfo.so_rport =
pcb->inp_fport;
ar->k_ar.ar_arg_sockinfo.so_lport =
pcb->inp_lport;
INP_RUNLOCK(pcb);
ARG_SET_VALID(ar, ARG_SOCKINFO);
}
break;
default:
/* XXXAUDIT: else? */
break;
}
}
/*
* Store a path as given by the user process for auditing into the audit
* record stored on the user thread. This function will allocate the memory
* to store the path info if not already available. This memory will be
* freed when the audit record is freed.
*/
static void
audit_arg_upath(struct thread *td, char *upath, char **pathp)
{
if (*pathp == NULL)
*pathp = malloc(MAXPATHLEN, M_AUDITPATH, M_WAITOK);
audit_canon_path(td, upath, *pathp);
}
void
audit_arg_upath1(struct thread *td, char *upath)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
audit_arg_upath(td, upath, &ar->k_ar.ar_arg_upath1);
ARG_SET_VALID(ar, ARG_UPATH1);
}
void
audit_arg_upath2(struct thread *td, char *upath)
{
struct kaudit_record *ar;
ar = currecord();
if (ar == NULL)
return;
audit_arg_upath(td, upath, &ar->k_ar.ar_arg_upath2);
ARG_SET_VALID(ar, ARG_UPATH2);
}
/*
* Function to save the path and vnode attr information into the audit
* record.
*
* It is assumed that the caller will hold any vnode locks necessary to
* perform a VOP_GETATTR() on the passed vnode.
*
* XXX: The attr code is very similar to vfs_vnops.c:vn_stat(), but always
* provides access to the generation number as we need that to construct the
* BSM file ID.
*
* XXX: We should accept the process argument from the caller, since it's
* very likely they already have a reference.
*
* XXX: Error handling in this function is poor.
*
* XXXAUDIT: Possibly KASSERT the path pointer is NULL?
*/
static int
audit_arg_vnode(struct vnode *vp, struct vnode_au_info *vnp)
{
struct vattr vattr;
int error;
/*
* Assume that if the caller is calling audit_arg_vnode() on a
* non-MPSAFE vnode, then it will have acquired Giant.
*/
VFS_ASSERT_GIANT(vp->v_mount);
ASSERT_VOP_LOCKED(vp, "audit_arg_vnode");
error = VOP_GETATTR(vp, &vattr, curthread->td_ucred);
if (error) {
/* XXX: How to handle this case? */
return (error);
}
vnp->vn_mode = vattr.va_mode;
vnp->vn_uid = vattr.va_uid;
vnp->vn_gid = vattr.va_gid;
vnp->vn_dev = vattr.va_rdev;
vnp->vn_fsid = vattr.va_fsid;
vnp->vn_fileid = vattr.va_fileid;
vnp->vn_gen = vattr.va_gen;
return (0);
}
void
audit_arg_vnode1(struct vnode *vp)
{
struct kaudit_record *ar;
int error;
ar = currecord();
if (ar == NULL)
return;
ARG_CLEAR_VALID(ar, ARG_VNODE1);
error = audit_arg_vnode(vp, &ar->k_ar.ar_arg_vnode1);
if (error == 0)
ARG_SET_VALID(ar, ARG_VNODE1);
}
void
audit_arg_vnode2(struct vnode *vp)
{
struct kaudit_record *ar;
int error;
ar = currecord();
if (ar == NULL)
return;
ARG_CLEAR_VALID(ar, ARG_VNODE2);
error = audit_arg_vnode(vp, &ar->k_ar.ar_arg_vnode2);
if (error == 0)
ARG_SET_VALID(ar, ARG_VNODE2);
}
/*
* Audit the argument strings passed to exec.
*/
void
audit_arg_argv(char *argv, int argc, int length)
{
struct kaudit_record *ar;
if (audit_argv == 0)
return;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_argv = malloc(length, M_AUDITTEXT, M_WAITOK);
bcopy(argv, ar->k_ar.ar_arg_argv, length);
ar->k_ar.ar_arg_argc = argc;
ARG_SET_VALID(ar, ARG_ARGV);
}
/*
* Audit the environment strings passed to exec.
*/
void
audit_arg_envv(char *envv, int envc, int length)
{
struct kaudit_record *ar;
if (audit_arge == 0)
return;
ar = currecord();
if (ar == NULL)
return;
ar->k_ar.ar_arg_envv = malloc(length, M_AUDITTEXT, M_WAITOK);
bcopy(envv, ar->k_ar.ar_arg_envv, length);
ar->k_ar.ar_arg_envc = envc;
ARG_SET_VALID(ar, ARG_ENVV);
}
/*
* The close() system call uses it's own audit call to capture the path/vnode
* information because those pieces are not easily obtained within the system
* call itself.
*/
void
audit_sysclose(struct thread *td, int fd)
{
struct kaudit_record *ar;
struct vnode *vp;
struct file *fp;
int vfslocked;
KASSERT(td != NULL, ("audit_sysclose: td == NULL"));
ar = currecord();
if (ar == NULL)
return;
audit_arg_fd(fd);
if (getvnode(td->td_proc->p_fd, fd, &fp) != 0)
return;
vp = fp->f_vnode;
vfslocked = VFS_LOCK_GIANT(vp->v_mount);
vn_lock(vp, LK_SHARED | LK_RETRY);
audit_arg_vnode1(vp);
VOP_UNLOCK(vp, 0);
VFS_UNLOCK_GIANT(vfslocked);
fdrop(fp, td);
}