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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 <errno.h>
  47.  
  48. /** Set capabilities.
  49.  *
  50.  * @param t Task whose capabilities are to be changed.
  51.  * @param caps New set of capabilities.
  52.  */
  53. void cap_set(task_t *t, cap_t caps)
  54. {
  55.     ipl_t ipl;
  56.    
  57.     ipl = interrupts_disable();
  58.     spinlock_lock(&t->lock);
  59.    
  60.     t->capabilities = caps;
  61.    
  62.     spinlock_unlock(&t->lock);
  63.     interrupts_restore(ipl);
  64. }
  65.  
  66. /** Get capabilities.
  67.  *
  68.  * @param t Task whose capabilities are to be returned.
  69.  * @return Task's capabilities.
  70.  */
  71. cap_t cap_get(task_t *t)
  72. {
  73.     ipl_t ipl;
  74.     cap_t caps;
  75.    
  76.     ipl = interrupts_disable();
  77.     spinlock_lock(&t->lock);
  78.    
  79.     caps = t->capabilities;
  80.    
  81.     spinlock_unlock(&t->lock);
  82.     interrupts_restore(ipl);
  83.    
  84.     return caps;
  85. }
  86.  
  87. /** Grant capabilities to a task.
  88.  *
  89.  * The calling task must have the CAP_CAP capability.
  90.  *
  91.  * @param uspace_taskid_arg Userspace structure holding destination task ID.
  92.  * @param caps Capabilities to grant.
  93.  *
  94.  * @return Zero on success or an error code from @ref errno.h.
  95.  */
  96. unative_t sys_cap_grant(sysarg64_t *uspace_taskid_arg, cap_t caps)
  97. {
  98.     sysarg64_t taskid_arg;
  99.     task_t *t;
  100.     ipl_t ipl;
  101.     int rc;
  102.    
  103.     if (!(cap_get(TASK) & CAP_CAP))
  104.         return (unative_t) EPERM;
  105.    
  106.     rc = copy_from_uspace(&taskid_arg, uspace_taskid_arg, sizeof(sysarg64_t));
  107.     if (rc != 0)
  108.         return (unative_t) rc;
  109.        
  110.     ipl = interrupts_disable();
  111.     spinlock_lock(&tasks_lock);
  112.     t = task_find_by_id((task_id_t) taskid_arg.value);
  113.     if ((!t) || (!context_check(CONTEXT, t->context))) {
  114.         spinlock_unlock(&tasks_lock);
  115.         interrupts_restore(ipl);
  116.         return (unative_t) ENOENT;
  117.     }
  118.    
  119.     spinlock_lock(&t->lock);
  120.     cap_set(t, cap_get(t) | caps);
  121.     spinlock_unlock(&t->lock);
  122.    
  123.     spinlock_unlock(&tasks_lock);
  124.     interrupts_restore(ipl);   
  125.     return 0;
  126. }
  127.  
  128. /** Revoke capabilities from a task.
  129.  *
  130.  * The calling task must have the CAP_CAP capability or the caller must
  131.  * attempt to revoke capabilities from itself.
  132.  *
  133.  * @param uspace_taskid_arg Userspace structure holding destination task ID.
  134.  * @param caps Capabilities to revoke.
  135.  *
  136.  * @return Zero on success or an error code from @ref errno.h.
  137.  */
  138. unative_t sys_cap_revoke(sysarg64_t *uspace_taskid_arg, cap_t caps)
  139. {
  140.     sysarg64_t taskid_arg;
  141.     task_t *t;
  142.     ipl_t ipl;
  143.     int rc;
  144.    
  145.     rc = copy_from_uspace(&taskid_arg, uspace_taskid_arg, sizeof(sysarg64_t));
  146.     if (rc != 0)
  147.         return (unative_t) rc;
  148.  
  149.     ipl = interrupts_disable();
  150.     spinlock_lock(&tasks_lock);
  151.     t = task_find_by_id((task_id_t) taskid_arg.value);
  152.     if ((!t) || (!context_check(CONTEXT, t->context))) {
  153.         spinlock_unlock(&tasks_lock);
  154.         interrupts_restore(ipl);
  155.         return (unative_t) ENOENT;
  156.     }
  157.  
  158.     /*
  159.      * Revoking capabilities is different from granting them in that
  160.      * a task can revoke capabilities from itself even if it
  161.      * doesn't have CAP_CAP.
  162.      */
  163.     if (!(cap_get(TASK) & CAP_CAP) || !(t == TASK)) {
  164.         spinlock_unlock(&tasks_lock);
  165.         interrupts_restore(ipl);
  166.         return (unative_t) EPERM;
  167.     }
  168.    
  169.     spinlock_lock(&t->lock);
  170.     cap_set(t, cap_get(t) & ~caps);
  171.     spinlock_unlock(&t->lock);
  172.  
  173.     spinlock_unlock(&tasks_lock);
  174.  
  175.     interrupts_restore(ipl);
  176.     return 0;
  177. }
  178.  
  179. /** @}
  180.  */
  181.  
  182.