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, " target=");
  29         audit_log_untrustedstring(ab, sa->aad->target);
  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         struct common_audit_data sa;
  44         struct apparmor_audit_data aad = {0,};
  45         sa.type = LSM_AUDIT_DATA_NONE;
  46         sa.aad = &aad;
  47         aad.op = OP_PTRACE;
  48         aad.target = target;
  49         aad.error = error;
  50
  51         return aa_audit(AUDIT_APPARMOR_AUTO, profile, GFP_ATOMIC, &sa,
  52                         audit_cb);
  53 }
  54
  55 /**
  56  * aa_may_ptrace - test if tracer task can trace the tracee
  57  * @tracer: profile of the task doing the tracing  (NOT NULL)
  58  * @tracee: task to be traced
  59  * @mode: whether PTRACE_MODE_READ || PTRACE_MODE_ATTACH
  60  *
  61  * Returns: %0 else error code if permission denied or error
  62  */
  63 int aa_may_ptrace(struct aa_profile *tracer, struct aa_profile *tracee,
  64                   unsigned int mode)
  65 {
  66         /* TODO: currently only based on capability, not extended ptrace
  67          *       rules,
  68          *       Test mode for PTRACE_MODE_READ || PTRACE_MODE_ATTACH
  69          */
  70
  71         if (unconfined(tracer) || tracer == tracee)
  72                 return 0;
  73         /* log this capability request */
  74         return aa_capable(tracer, CAP_SYS_PTRACE, 1);
  75 }
  76
  77 /**
  78  * aa_ptrace - do ptrace permission check and auditing
  79  * @tracer: task doing the tracing (NOT NULL)
  80  * @tracee: task being traced (NOT NULL)
  81  * @mode: ptrace mode either PTRACE_MODE_READ || PTRACE_MODE_ATTACH
  82  *
  83  * Returns: %0 else error code if permission denied or error
  84  */
  85 int aa_ptrace(struct task_struct *tracer, struct task_struct *tracee,
  86               unsigned int mode)
  87 {
  88         /*
  89          * tracer can ptrace tracee when
  90          * - tracer is unconfined ||
  91          *   - tracer is in complain mode
  92          *   - tracer has rules allowing it to trace tracee currently this is:
  93          *       - confined by the same profile ||
  94          *       - tracer profile has CAP_SYS_PTRACE
  95          */
  96
  97         struct aa_profile *tracer_p = aa_get_task_profile(tracer);
  98         int error = 0;
  99
 100         if (!unconfined(tracer_p)) {
 101                 struct aa_profile *tracee_p = aa_get_task_profile(tracee);
 102
 103                 error = aa_may_ptrace(tracer_p, tracee_p, mode);
 104                 error = aa_audit_ptrace(tracer_p, tracee_p, error);
 105
 106                 aa_put_profile(tracee_p);
 107         }
 108         aa_put_profile(tracer_p);
 109
 110         return error;
 111 }