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#include "include/ipc.h"
  23
  24/* call back to audit ptrace fields */
  25static 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 */
  40static int aa_audit_ptrace(struct aa_profile *profile,
  41                           struct aa_profile *target, int error)
  42{
  43        struct common_audit_data sa;
  44        COMMON_AUDIT_DATA_INIT(&sa, NONE);
  45        sa.aad.op = OP_PTRACE;
  46        sa.aad.target = target;
  47        sa.aad.error = error;
  48
  49        return aa_audit(AUDIT_APPARMOR_AUTO, profile, GFP_ATOMIC, &sa,
  50                        audit_cb);
  51}
  52
  53/**
  54 * aa_may_ptrace - test if tracer task can trace the tracee
  55 * @tracer_task: task who will do the tracing  (NOT NULL)
  56 * @tracer: profile of the task doing the tracing  (NOT NULL)
  57 * @tracee: task to be traced
  58 * @mode: whether PTRACE_MODE_READ || PTRACE_MODE_ATTACH
  59 *
  60 * Returns: %0 else error code if permission denied or error
  61 */
  62int aa_may_ptrace(struct task_struct *tracer_task, struct aa_profile *tracer,
  63                  struct aa_profile *tracee, unsigned int mode)
  64{
  65        /* TODO: currently only based on capability, not extended ptrace
  66         *       rules,
  67         *       Test mode for PTRACE_MODE_READ || PTRACE_MODE_ATTACH
  68         */
  69
  70        if (unconfined(tracer) || tracer == tracee)
  71                return 0;
  72        /* log this capability request */
  73        return aa_capable(tracer_task, tracer, CAP_SYS_PTRACE, 1);
  74}
  75
  76/**
  77 * aa_ptrace - do ptrace permission check and auditing
  78 * @tracer: task doing the tracing (NOT NULL)
  79 * @tracee: task being traced (NOT NULL)
  80 * @mode: ptrace mode either PTRACE_MODE_READ || PTRACE_MODE_ATTACH
  81 *
  82 * Returns: %0 else error code if permission denied or error
  83 */
  84int aa_ptrace(struct task_struct *tracer, struct task_struct *tracee,
  85              unsigned int mode)
  86{
  87        /*
  88         * tracer can ptrace tracee when
  89         * - tracer is unconfined ||
  90         *   - tracer is in complain mode
  91         *   - tracer has rules allowing it to trace tracee currently this is:
  92         *       - confined by the same profile ||
  93         *       - tracer profile has CAP_SYS_PTRACE
  94         */
  95
  96        struct aa_profile *tracer_p;
  97        /* cred released below */
  98        const struct cred *cred = get_task_cred(tracer);
  99        int error = 0;
 100        tracer_p = aa_cred_profile(cred);
 101
 102        if (!unconfined(tracer_p)) {
 103                /* lcred released below */
 104                const struct cred *lcred = get_task_cred(tracee);
 105                struct aa_profile *tracee_p = aa_cred_profile(lcred);
 106
 107                error = aa_may_ptrace(tracer, tracer_p, tracee_p, mode);
 108                error = aa_audit_ptrace(tracer_p, tracee_p, error);
 109
 110                put_cred(lcred);
 111        }
 112        put_cred(cred);
 113
 114        return error;
 115}
 116