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/**
* @file
*
* @ingroup rtems_bsd_rtems
*
* @brief TODO.
*/
/*
* Copyright (c) 2009, 2010 embedded brains GmbH. All rights reserved.
*
* embedded brains GmbH
* Obere Lagerstr. 30
* 82178 Puchheim
* Germany
* <rtems@embedded-brains.de>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*/
#include <freebsd/machine/rtems-bsd-config.h>
#include <freebsd/sys/types.h>
#include <freebsd/sys/systm.h>
#include <freebsd/vm/uma.h>
#include <freebsd/sys/malloc.h>
#include <freebsd/sys/ucred.h>
#include <freebsd/sys/refcount.h>
#include <freebsd/sys/sysctl.h>
static MALLOC_DEFINE(M_CRED, "cred", "credentials");
static void crextend(struct ucred *cr, int n);
static void crsetgroups_locked(struct ucred *cr, int ngrp,
gid_t *groups);
/*
* Allocate a zeroed cred structure.
*/
struct ucred *
crget(void)
{
register struct ucred *cr;
cr = malloc(sizeof(*cr), M_CRED, M_WAITOK | M_ZERO);
refcount_init(&cr->cr_ref, 1);
#ifdef AUDIT
audit_cred_init(cr);
#endif
#ifdef MAC
mac_cred_init(cr);
#endif
crextend(cr, XU_NGROUPS);
return (cr);
}
/*
* Claim another reference to a ucred structure.
*/
struct ucred *
crhold(struct ucred *cr)
{
refcount_acquire(&cr->cr_ref);
return (cr);
}
/*
* Free a cred structure. Throws away space when ref count gets to 0.
*/
void
crfree(struct ucred *cr)
{
KASSERT(cr->cr_ref > 0, ("bad ucred refcount: %d", cr->cr_ref));
KASSERT(cr->cr_ref != 0xdeadc0de, ("dangling reference to ucred"));
if (refcount_release(&cr->cr_ref)) {
/*
* Some callers of crget(), such as nfs_statfs(),
* allocate a temporary credential, but don't
* allocate a uidinfo structure.
*/
if (cr->cr_uidinfo != NULL)
uifree(cr->cr_uidinfo);
if (cr->cr_ruidinfo != NULL)
uifree(cr->cr_ruidinfo);
/*
* Free a prison, if any.
*/
if (cr->cr_prison != NULL)
prison_free(cr->cr_prison);
#ifdef AUDIT
audit_cred_destroy(cr);
#endif
#ifdef MAC
mac_cred_destroy(cr);
#endif
free(cr->cr_groups, M_CRED);
free(cr, M_CRED);
}
}
/*
* Check to see if this ucred is shared.
*/
int
crshared(struct ucred *cr)
{
return (cr->cr_ref > 1);
}
/*
* Copy a ucred's contents from a template. Does not block.
*/
void
crcopy(struct ucred *dest, struct ucred *src)
{
KASSERT(crshared(dest) == 0, ("crcopy of shared ucred"));
bcopy(&src->cr_startcopy, &dest->cr_startcopy,
(unsigned)((caddr_t)&src->cr_endcopy -
(caddr_t)&src->cr_startcopy));
crsetgroups(dest, src->cr_ngroups, src->cr_groups);
uihold(dest->cr_uidinfo);
uihold(dest->cr_ruidinfo);
prison_hold(dest->cr_prison);
#ifdef AUDIT
audit_cred_copy(src, dest);
#endif
#ifdef MAC
mac_cred_copy(src, dest);
#endif
}
/*
* Dup cred struct to a new held one.
*/
struct ucred *
crdup(struct ucred *cr)
{
struct ucred *newcr;
newcr = crget();
crcopy(newcr, cr);
return (newcr);
}
/*
* Extend the passed in credential to hold n items.
*/
static void
crextend(struct ucred *cr, int n)
{
int cnt;
/* Truncate? */
if (n <= cr->cr_agroups)
return;
/*
* We extend by 2 each time since we're using a power of two
* allocator until we need enough groups to fill a page.
* Once we're allocating multiple pages, only allocate as many
* as we actually need. The case of processes needing a
* non-power of two number of pages seems more likely than
* a real world process that adds thousands of groups one at a
* time.
*/
if ( n < PAGE_SIZE / sizeof(gid_t) ) {
if (cr->cr_agroups == 0)
cnt = MINALLOCSIZE / sizeof(gid_t);
else
cnt = cr->cr_agroups * 2;
while (cnt < n)
cnt *= 2;
} else
cnt = roundup2(n, PAGE_SIZE / sizeof(gid_t));
/* Free the old array. */
if (cr->cr_groups)
free(cr->cr_groups, M_CRED);
cr->cr_groups = malloc(cnt * sizeof(gid_t), M_CRED, M_WAITOK | M_ZERO);
cr->cr_agroups = cnt;
}
/*
* Copy groups in to a credential, preserving any necessary invariants.
* Currently this includes the sorting of all supplemental gids.
* crextend() must have been called before hand to ensure sufficient
* space is available.
*/
static void
crsetgroups_locked(struct ucred *cr, int ngrp, gid_t *groups)
{
int i;
int j;
gid_t g;
KASSERT(cr->cr_agroups >= ngrp, ("cr_ngroups is too small"));
bcopy(groups, cr->cr_groups, ngrp * sizeof(gid_t));
cr->cr_ngroups = ngrp;
/*
* Sort all groups except cr_groups[0] to allow groupmember to
* perform a binary search.
*
* XXX: If large numbers of groups become common this should
* be replaced with shell sort like linux uses or possibly
* heap sort.
*/
for (i = 2; i < ngrp; i++) {
g = cr->cr_groups[i];
for (j = i-1; j >= 1 && g < cr->cr_groups[j]; j--)
cr->cr_groups[j + 1] = cr->cr_groups[j];
cr->cr_groups[j + 1] = g;
}
}
/*
* Copy groups in to a credential after expanding it if required.
* Truncate the list to (ngroups_max + 1) if it is too large.
*/
void
crsetgroups(struct ucred *cr, int ngrp, gid_t *groups)
{
if (ngrp > ngroups_max + 1)
ngrp = ngroups_max + 1;
crextend(cr, ngrp);
crsetgroups_locked(cr, ngrp, groups);
}
SYSCTL_NODE(_security, OID_AUTO, bsd, CTLFLAG_RW, 0, "BSD security policy");
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