/*
* Copyright (C) 2006 Jakub Jermar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - 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.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 THE AUTHOR 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.
*/
/**
* @file cap.c
* @brief Capabilities control.
*
* @see cap.h
*/
#include <security/cap.h>
#include <proc/task.h>
#include <synch/spinlock.h>
#include <syscall/sysarg64.h>
#include <syscall/copy.h>
#include <arch.h>
#include <typedefs.h>
#include <errno.h>
/** Set capabilities.
*
* @param t Task whose capabilities are to be changed.
* @param caps New set of capabilities.
*/
void cap_set(task_t *t, cap_t caps)
{
ipl_t ipl;
ipl = interrupts_disable();
spinlock_lock(&t->lock);
t->capabilities = caps;
spinlock_unlock(&t->lock);
interrupts_restore(ipl);
}
/** Get capabilities.
*
* @param t Task whose capabilities are to be returned.
* @return Task's capabilities.
*/
cap_t cap_get(task_t *t)
{
ipl_t ipl;
cap_t caps;
ipl = interrupts_disable();
spinlock_lock(&t->lock);
caps = t->capabilities;
spinlock_unlock(&t->lock);
interrupts_restore(ipl);
return caps;
}
/** Grant capabilities to a task.
*
* The calling task must have the CAP_CAP capability.
*
* @param uspace_taskid_arg Userspace structure holding destination task ID.
* @param caps Capabilities to grant.
*
* @return Zero on success or an error code from @ref errno.h.
*/
__native sys_cap_grant(sysarg64_t *uspace_taskid_arg, cap_t caps)
{
sysarg64_t taskid_arg;
task_t *t;
ipl_t ipl;
int rc;
if (!(cap_get(TASK) & CAP_CAP))
return (__native) EPERM;
rc = copy_from_uspace(&taskid_arg, uspace_taskid_arg, sizeof(sysarg64_t));
if (rc != 0)
return (__native) rc;
ipl = interrupts_disable();
spinlock_lock(&tasks_lock);
t = task_find_by_id((task_id_t) taskid_arg.value);
if (!t) {
spinlock_unlock(&tasks_lock);
interrupts_restore(ipl);
return (__native) ENOENT;
}
spinlock_lock(&t->lock);
cap_set(t, cap_get(t) | caps);
spinlock_unlock(&t->lock);
spinlock_unlock(&tasks_lock);
interrupts_restore(ipl);
return 0;
}
/** Revoke capabilities from a task.
*
* The calling task must have the CAP_CAP capability or the caller must
* attempt to revoke capabilities from itself.
*
* @param uspace_taskid_arg Userspace structure holding destination task ID.
* @param caps Capabilities to revoke.
*
* @return Zero on success or an error code from @ref errno.h.
*/
__native sys_cap_revoke(sysarg64_t *uspace_taskid_arg, cap_t caps)
{
sysarg64_t taskid_arg;
task_t *t;
ipl_t ipl;
int rc;
rc = copy_from_uspace(&taskid_arg, uspace_taskid_arg, sizeof(sysarg64_t));
if (rc != 0)
return (__native) rc;
ipl = interrupts_disable();
spinlock_lock(&tasks_lock);
t = task_find_by_id((task_id_t) taskid_arg.value);
if (!t) {
spinlock_unlock(&tasks_lock);
interrupts_restore(ipl);
return (__native) ENOENT;
}
/*
* Revoking capabilities is different from granting them in that
* a task can revoke capabilities from itself even if it
* doesn't have CAP_CAP.
*/
if (!(cap_get(TASK) & CAP_CAP) || !(t == TASK)) {
spinlock_unlock(&tasks_lock);
interrupts_restore(ipl);
return (__native) EPERM;
}
spinlock_lock(&t->lock);
cap_set(t, cap_get(t) & ~caps);
spinlock_unlock(&t->lock);
spinlock_unlock(&tasks_lock);
interrupts_restore(ipl);
return 0;
}