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  1. /*
  2.  * Copyright (c) 2006 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup generic
  30.  * @{
  31.  */
  32.  
  33. /**
  34.  * @file    cap.c
  35.  * @brief   Capabilities control.
  36.  *
  37.  * @see cap.h
  38.  */
  39.  
  40. #include <security/cap.h>
  41. #include <proc/task.h>
  42. #include <synch/spinlock.h>
  43. #include <syscall/sysarg64.h>
  44. #include <syscall/copy.h>
  45. #include <arch.h>
  46. #include <typedefs.h>
  47. #include <errno.h>
  48.  
  49. /** Set capabilities.
  50.  *
  51.  * @param t Task whose capabilities are to be changed.
  52.  * @param caps New set of capabilities.
  53.  */
  54. void cap_set(task_t *t, cap_t caps)
  55. {
  56.     ipl_t ipl;
  57.    
  58.     ipl = interrupts_disable();
  59.     spinlock_lock(&t->lock);
  60.    
  61.     t->capabilities = caps;
  62.    
  63.     spinlock_unlock(&t->lock);
  64.     interrupts_restore(ipl);
  65. }
  66.  
  67. /** Get capabilities.
  68.  *
  69.  * @param t Task whose capabilities are to be returned.
  70.  * @return Task's capabilities.
  71.  */
  72. cap_t cap_get(task_t *t)
  73. {
  74.     ipl_t ipl;
  75.     cap_t caps;
  76.    
  77.     ipl = interrupts_disable();
  78.     spinlock_lock(&t->lock);
  79.    
  80.     caps = t->capabilities;
  81.    
  82.     spinlock_unlock(&t->lock);
  83.     interrupts_restore(ipl);
  84.    
  85.     return caps;
  86. }
  87.  
  88. /** Grant capabilities to a task.
  89.  *
  90.  * The calling task must have the CAP_CAP capability.
  91.  *
  92.  * @param uspace_taskid_arg Userspace structure holding destination task ID.
  93.  * @param caps Capabilities to grant.
  94.  *
  95.  * @return Zero on success or an error code from @ref errno.h.
  96.  */
  97. unative_t sys_cap_grant(sysarg64_t *uspace_taskid_arg, cap_t caps)
  98. {
  99.     sysarg64_t taskid_arg;
  100.     task_t *t;
  101.     ipl_t ipl;
  102.     int rc;
  103.    
  104.     if (!(cap_get(TASK) & CAP_CAP))
  105.         return (unative_t) EPERM;
  106.    
  107.     rc = copy_from_uspace(&taskid_arg, uspace_taskid_arg, sizeof(sysarg64_t));
  108.     if (rc != 0)
  109.         return (unative_t) rc;
  110.        
  111.     ipl = interrupts_disable();
  112.     spinlock_lock(&tasks_lock);
  113.     t = task_find_by_id((task_id_t) taskid_arg.value);
  114.     if ((!t) || (!context_check(CONTEXT, t->context))) {
  115.         spinlock_unlock(&tasks_lock);
  116.         interrupts_restore(ipl);
  117.         return (unative_t) ENOENT;
  118.     }
  119.    
  120.     spinlock_lock(&t->lock);
  121.     cap_set(t, cap_get(t) | caps);
  122.     spinlock_unlock(&t->lock);
  123.    
  124.     spinlock_unlock(&tasks_lock);
  125.     interrupts_restore(ipl);   
  126.     return 0;
  127. }
  128.  
  129. /** Revoke capabilities from a task.
  130.  *
  131.  * The calling task must have the CAP_CAP capability or the caller must
  132.  * attempt to revoke capabilities from itself.
  133.  *
  134.  * @param uspace_taskid_arg Userspace structure holding destination task ID.
  135.  * @param caps Capabilities to revoke.
  136.  *
  137.  * @return Zero on success or an error code from @ref errno.h.
  138.  */
  139. unative_t sys_cap_revoke(sysarg64_t *uspace_taskid_arg, cap_t caps)
  140. {
  141.     sysarg64_t taskid_arg;
  142.     task_t *t;
  143.     ipl_t ipl;
  144.     int rc;
  145.    
  146.     rc = copy_from_uspace(&taskid_arg, uspace_taskid_arg, sizeof(sysarg64_t));
  147.     if (rc != 0)
  148.         return (unative_t) rc;
  149.  
  150.     ipl = interrupts_disable();
  151.     spinlock_lock(&tasks_lock);
  152.     t = task_find_by_id((task_id_t) taskid_arg.value);
  153.     if ((!t) || (!context_check(CONTEXT, t->context))) {
  154.         spinlock_unlock(&tasks_lock);
  155.         interrupts_restore(ipl);
  156.         return (unative_t) ENOENT;
  157.     }
  158.  
  159.     /*
  160.      * Revoking capabilities is different from granting them in that
  161.      * a task can revoke capabilities from itself even if it
  162.      * doesn't have CAP_CAP.
  163.      */
  164.     if (!(cap_get(TASK) & CAP_CAP) || !(t == TASK)) {
  165.         spinlock_unlock(&tasks_lock);
  166.         interrupts_restore(ipl);
  167.         return (unative_t) EPERM;
  168.     }
  169.    
  170.     spinlock_lock(&t->lock);
  171.     cap_set(t, cap_get(t) & ~caps);
  172.     spinlock_unlock(&t->lock);
  173.  
  174.     spinlock_unlock(&tasks_lock);
  175.  
  176.     interrupts_restore(ipl);
  177.     return 0;
  178. }
  179.  
  180. /** @}
  181.  */
  182.  
  183.