LXR linux/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
  23/* call back to audit ptrace fields */
  24static void audit_cb(struct audit_buffer *ab, void *va)
  25{
  26        struct common_audit_data *sa = va;
  27        audit_log_format(ab, " target=");
  28        audit_log_untrustedstring(ab, sa->aad.target);
  29}
  30
  31/**
  32 * aa_audit_ptrace - do auditing for ptrace
  33 * @profile: profile being enforced  (NOT NULL)
  34 * @target: profile being traced (NOT NULL)
  35 * @error: error condition
  36 *
  37 * Returns: %0 or error code
  38 */
  39static int aa_audit_ptrace(struct aa_profile *profile,
  40                           struct aa_profile *target, int error)
  41{
  42        struct common_audit_data sa;
  43        COMMON_AUDIT_DATA_INIT(&sa, NONE);
  44        sa.aad.op = OP_PTRACE;
  45        sa.aad.target = target;
  46        sa.aad.error = error;
  47
  48        return aa_audit(AUDIT_APPARMOR_AUTO, profile, GFP_ATOMIC, &sa,
  49                        audit_cb);
  50}
  51
  52/**
  53 * aa_may_ptrace - test if tracer task can trace the tracee
  54 * @tracer_task: task who will do the tracing  (NOT NULL)
  55 * @tracer: profile of the task doing the tracing  (NOT NULL)
  56 * @tracee: task to be traced
  57 * @mode: whether PTRACE_MODE_READ || PTRACE_MODE_ATTACH
  58 *
  59 * Returns: %0 else error code if permission denied or error
  60 */
  61int aa_may_ptrace(struct task_struct *tracer_task, struct aa_profile *tracer,
  62                  struct aa_profile *tracee, unsigned int mode)
  63{
  64        /* TODO: currently only based on capability, not extended ptrace
  65         *       rules,
  66         *       Test mode for PTRACE_MODE_READ || PTRACE_MODE_ATTACH
  67         */
  68
  69        if (unconfined(tracer) || tracer == tracee)
  70                return 0;
  71        /* log this capability request */
  72        return aa_capable(tracer_task, tracer, CAP_SYS_PTRACE, 1);
  73}
  74
  75/**
  76 * aa_ptrace - do ptrace permission check and auditing
  77 * @tracer: task doing the tracing (NOT NULL)
  78 * @tracee: task being traced (NOT NULL)
  79 * @mode: ptrace mode either PTRACE_MODE_READ || PTRACE_MODE_ATTACH
  80 *
  81 * Returns: %0 else error code if permission denied or error
  82 */
  83int aa_ptrace(struct task_struct *tracer, struct task_struct *tracee,
  84              unsigned int mode)
  85{
  86        /*
  87         * tracer can ptrace tracee when
  88         * - tracer is unconfined ||
  89         *   - tracer is in complain mode
  90         *   - tracer has rules allowing it to trace tracee currently this is:
  91         *       - confined by the same profile ||
  92         *       - tracer profile has CAP_SYS_PTRACE
  93         */
  94
  95        struct aa_profile *tracer_p;
  96        /* cred released below */
  97        const struct cred *cred = get_task_cred(tracer);
  98        int error = 0;
  99        tracer_p = aa_cred_profile(cred);
 100
 101        if (!unconfined(tracer_p)) {
 102                /* lcred released below */
 103                const struct cred *lcred = get_task_cred(tracee);
 104                struct aa_profile *tracee_p = aa_cred_profile(lcred);
 105
 106                error = aa_may_ptrace(tracer, tracer_p, tracee_p, mode);
 107                error = aa_audit_ptrace(tracer_p, tracee_p, error);
 108
 109                put_cred(lcred);
 110        }
 111        put_cred(cred);
 112
 113        return error;
 114}
 115