/*
* Interface to set the effective and permitted privileges for
* a credential; this interface does no security checks and is
* intended for kernel (file)servers creating credentials with
* specific privileges.
*/
int
crsetpriv(cred_t *cr, ...)
{
va_list ap;
const char *privnm;
ASSERT(cr->cr_ref <= 2);
priv_set_PA(cr);
va_start(ap, cr);
while ((privnm = va_arg(ap, const char *)) != NULL) {
int priv = priv_getbyname(privnm, 0);
if (priv < 0)
return (-1);
priv_addset(&CR_PPRIV(cr), priv);
priv_addset(&CR_EPRIV(cr), priv);
}
priv_adjust_PA(cr);
va_end(ap);
return (0);
}
int
setpflags(uint_t flag, uint_t val, cred_t *tcr)
{
cred_t *cr, *pcr;
proc_t *p = curproc;
uint_t newflags;
boolean_t use_curcred = (tcr == NULL);
if (val > 1 || (flag != PRIV_DEBUG && flag != PRIV_AWARE &&
flag != NET_MAC_AWARE && flag != NET_MAC_AWARE_INHERIT &&
flag != __PROC_PROTECT && flag != PRIV_XPOLICY &&
flag != PRIV_AWARE_RESET && flag != PRIV_PFEXEC)) {
return (EINVAL);
}
if (flag == __PROC_PROTECT) {
mutex_enter(&p->p_lock);
if (val == 0)
p->p_flag &= ~SNOCD;
else
p->p_flag |= SNOCD;
mutex_exit(&p->p_lock);
return (0);
}
if (use_curcred) {
cr = cralloc();
mutex_enter(&p->p_crlock);
pcr = p->p_cred;
} else {
cr = pcr = tcr;
}
newflags = CR_FLAGS(pcr);
if (val != 0) {
if (flag == PRIV_AWARE)
newflags &= ~PRIV_AWARE_RESET;
newflags |= flag;
} else {
newflags &= ~flag;
}
/* No change */
if (CR_FLAGS(pcr) == newflags) {
if (use_curcred) {
mutex_exit(&p->p_crlock);
crfree(cr);
}
return (0);
}
/*
* Setting either the NET_MAC_AWARE or NET_MAC_AWARE_INHERIT
* flags is a restricted operation.
*
* When invoked via the PRIVSYS_SETPFLAGS syscall
* we require that the current cred has the net_mac_aware
* privilege in its effective set.
*
* When called from within the kernel by label-aware
* services such as NFS, we don't require a privilege check.
*
*/
if ((flag == NET_MAC_AWARE || flag == NET_MAC_AWARE_INHERIT) &&
(val == 1) && use_curcred) {
if (secpolicy_net_mac_aware(pcr) != 0) {
mutex_exit(&p->p_crlock);
crfree(cr);
return (EPERM);
}
}
/* Trying to unset PA; if we can't, return an error */
if (flag == PRIV_AWARE && val == 0 && !priv_can_clear_PA(pcr)) {
if (use_curcred) {
mutex_exit(&p->p_crlock);
crfree(cr);
}
return (EPERM);
}
/* Committed to changing the flag */
if (use_curcred)
crcopy_to(pcr, cr);
if (flag == PRIV_AWARE) {
if (val != 0)
priv_set_PA(cr);
else
priv_adjust_PA(cr);
} else {
CR_FLAGS(cr) = newflags;
}
/*
* Unsetting the flag has as side effect getting rid of
* the per-credential policy.
*/
if (flag == PRIV_XPOLICY && val == 0)
crsetcrklpd(cr, NULL);
if (use_curcred) {
p->p_cred = cr;
mutex_exit(&p->p_crlock);
crset(p, cr);
}
return (0);
}
/*
* Guts of pr_spriv:
*
* Set the privileges of a process.
*
* In order to set the privileges, the setting process will need to
* have those privileges in its effective set in order to prevent
* specially privileged processes to easily gain additional privileges.
* Pre-existing privileges can be retained. To change any privileges,
* PRIV_PROC_OWNER needs to be asserted.
*
* In formula:
*
* S' <= S || S' <= S + Ea
*
* the new set must either be subset of the old set or a subset of
* the oldset merged with the effective set of the acting process; or just:
*
* S' <= S + Ea
*
* It's not legal to grow the limit set this way.
*
*/
int
priv_pr_spriv(proc_t *p, prpriv_t *prpriv, const cred_t *cr)
{
cred_t *oldcred;
cred_t *newcred;
int i;
int err = EPERM;
cred_priv_t *cp, *ocp;
priv_set_t eset;
ASSERT(MUTEX_HELD(&p->p_lock));
/*
* Set must have proper dimension; infosize must be absent
* or properly sized.
*/
if (prpriv->pr_nsets != PRIV_NSET ||
prpriv->pr_setsize != PRIV_SETSIZE ||
(prpriv->pr_infosize & (sizeof (uint32_t) - 1)) != 0 ||
prpriv->pr_infosize > priv_info->priv_infosize ||
prpriv->pr_infosize < 0)
return (EINVAL);
mutex_exit(&p->p_lock);
if (priv_proc_cred_perm(cr, p, &oldcred, VWRITE) != 0) {
mutex_enter(&p->p_lock);
return (EPERM);
}
newcred = crdup(oldcred);
/* Copy the privilege sets from prpriv to newcred */
bcopy(prpriv->pr_sets, CR_PRIVSETS(newcred), PRIV_SETBYTES);
cp = &newcred->cr_priv;
ocp = &oldcred->cr_priv;
eset = CR_OEPRIV(cr);
priv_intersect(&CR_LPRIV(oldcred), &eset);
/*
* Verify the constraints laid out:
* for the limit set, we require that the new set is a subset
* of the old limit set.
* for all other sets, we require that the new set is either a
* subset of the old set or a subset of the intersection of
* the old limit set and the effective set of the acting process.
*/
for (i = 0; i < PRIV_NSET; i++)
if (!priv_issubset(&cp->crprivs[i], &ocp->crprivs[i]) &&
(i == PRIV_LIMIT || !priv_issubset(&cp->crprivs[i], &eset)))
break;
crfree(oldcred);
if (i < PRIV_NSET || !priv_valid(newcred))
goto err;
/* Load the settable privilege information */
if (prpriv->pr_infosize > 0) {
char *x = (char *)prpriv + PRIV_PRPRIV_INFO_OFFSET(prpriv);
char *lastx = x + prpriv->pr_infosize;
while (x < lastx) {
priv_info_t *pi = (priv_info_t *)x;
priv_info_uint_t *pii;
switch (pi->priv_info_type) {
case PRIV_INFO_FLAGS:
pii = (priv_info_uint_t *)x;
if (pii->info.priv_info_size != sizeof (*pii)) {
err = EINVAL;
goto err;
}
CR_FLAGS(newcred) &= ~PRIV_USER;
CR_FLAGS(newcred) |= (pii->val & PRIV_USER);
break;
default:
err = EINVAL;
goto err;
}
/* Guarantee alignment and forward progress */
if ((pi->priv_info_size & (sizeof (uint32_t) - 1)) ||
pi->priv_info_size < sizeof (*pi) ||
lastx - x > pi->priv_info_size) {
err = EINVAL;
goto err;
}
x += pi->priv_info_size;
}
}
/*
* We'll try to copy the privilege aware flag; but since the
* privileges sets are all individually set, they are set
* as if we're privilege aware. If PRIV_AWARE wasn't set
* or was explicitely unset, we need to set the flag and then
* try to get rid of it.
*/
if ((CR_FLAGS(newcred) & PRIV_AWARE) == 0) {
CR_FLAGS(newcred) |= PRIV_AWARE;
priv_adjust_PA(newcred);
}
mutex_enter(&p->p_crlock);
oldcred = p->p_cred;
p->p_cred = newcred;
mutex_exit(&p->p_crlock);
crfree(oldcred);
mutex_enter(&p->p_lock);
return (0);
err:
crfree(newcred);
mutex_enter(&p->p_lock);
return (err);
}
