security/apparmor/ipc.c

   1 /*
   2  * AppArmor security module
   3  *
   4  * This file contains AppArmor ipc mediation
   5  *
   6  * Copyright (C) 1998-2008 Novell/SUSE
   7  * Copyright 2009-2010 Canonical Ltd.
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License as
  11  * published by the Free Software Foundation, version 2 of the
  12  * License.
  13  */
  14
  15 #include <linux/gfp.h>
  16 #include <linux/ptrace.h>
  17
  18 #include "include/audit.h"
  19 #include "include/capability.h"
  20 #include "include/context.h"
  21 #include "include/policy.h"
  22 #include "include/ipc.h"
  23
  24 /* call back to audit ptrace fields */
  25 static void audit_cb(struct audit_buffer *ab, void *va)
  26 {
  27         struct common_audit_data *sa = va;
  28         audit_log_format(ab, " peer=");
  29         audit_log_untrustedstring(ab, aad(sa)->peer->base.hname);
  30 }
  31
  32 /**
  33  * aa_audit_ptrace - do auditing for ptrace
  34  * @profile: profile being enforced  (NOT NULL)
  35  * @target: profile being traced (NOT NULL)
  36  * @error: error condition
  37  *
  38  * Returns: %0 or error code
  39  */
  40 static int aa_audit_ptrace(struct aa_profile *profile,
  41                            struct aa_profile *target, int error)
  42 {
  43         DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_PTRACE);
  44
  45         aad(&sa)->peer = target;
  46         aad(&sa)->error = error;
  47
  48         return aa_audit(AUDIT_APPARMOR_AUTO, profile, &sa, audit_cb);
  49 }
  50
  51 /**
  52  * aa_may_ptrace - test if tracer task can trace the tracee
  53  * @tracer: profile of the task doing the tracing  (NOT NULL)
  54  * @tracee: task to be traced
  55  * @mode: whether PTRACE_MODE_READ || PTRACE_MODE_ATTACH
  56  *
  57  * Returns: %0 else error code if permission denied or error
  58  */
  59 int aa_may_ptrace(struct aa_profile *tracer, struct aa_profile *tracee,
  60                   unsigned int mode)
  61 {
  62         /* TODO: currently only based on capability, not extended ptrace
  63          *       rules,
  64          *       Test mode for PTRACE_MODE_READ || PTRACE_MODE_ATTACH
  65          */
  66
  67         if (unconfined(tracer) || tracer == tracee)
  68                 return 0;
  69         /* log this capability request */
  70         return aa_capable(tracer, CAP_SYS_PTRACE, 1);
  71 }
  72
  73 /**
  74  * aa_ptrace - do ptrace permission check and auditing
  75  * @tracer: task doing the tracing (NOT NULL)
  76  * @tracee: task being traced (NOT NULL)
  77  * @mode: ptrace mode either PTRACE_MODE_READ || PTRACE_MODE_ATTACH
  78  *
  79  * Returns: %0 else error code if permission denied or error
  80  */
  81 int aa_ptrace(struct task_struct *tracer, struct task_struct *tracee,
  82               unsigned int mode)
  83 {
  84         /*
  85          * tracer can ptrace tracee when
  86          * - tracer is unconfined ||
  87          *   - tracer is in complain mode
  88          *   - tracer has rules allowing it to trace tracee currently this is:
  89          *       - confined by the same profile ||
  90          *       - tracer profile has CAP_SYS_PTRACE
  91          */
  92
  93         struct aa_profile *tracer_p = aa_get_task_profile(tracer);
  94         int error = 0;
  95
  96         if (!unconfined(tracer_p)) {
  97                 struct aa_profile *tracee_p = aa_get_task_profile(tracee);
  98
  99                 error = aa_may_ptrace(tracer_p, tracee_p, mode);
 100                 error = aa_audit_ptrace(tracer_p, tracee_p, error);
 101
 102                 aa_put_profile(tracee_p);
 103         }
 104         aa_put_profile(tracer_p);
 105
 106         return error;
 107 }