223 lines
6.2 KiB
C
223 lines
6.2 KiB
C
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/*
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* AppArmor security module
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*
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* This file contains AppArmor ipc mediation
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*
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* Copyright (C) 1998-2008 Novell/SUSE
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* Copyright 2009-2017 Canonical Ltd.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation, version 2 of the
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* License.
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*/
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#include <linux/gfp.h>
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#include <linux/ptrace.h>
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#include "include/audit.h"
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#include "include/capability.h"
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#include "include/cred.h"
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#include "include/policy.h"
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#include "include/ipc.h"
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#include "include/sig_names.h"
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/**
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* audit_ptrace_mask - convert mask to permission string
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* @buffer: buffer to write string to (NOT NULL)
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* @mask: permission mask to convert
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*/
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static void audit_ptrace_mask(struct audit_buffer *ab, u32 mask)
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{
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switch (mask) {
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case MAY_READ:
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audit_log_string(ab, "read");
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break;
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case MAY_WRITE:
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audit_log_string(ab, "trace");
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break;
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case AA_MAY_BE_READ:
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audit_log_string(ab, "readby");
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break;
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case AA_MAY_BE_TRACED:
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audit_log_string(ab, "tracedby");
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break;
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}
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}
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/* call back to audit ptrace fields */
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static void audit_ptrace_cb(struct audit_buffer *ab, void *va)
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{
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struct common_audit_data *sa = va;
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if (aad(sa)->request & AA_PTRACE_PERM_MASK) {
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audit_log_format(ab, " requested_mask=");
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audit_ptrace_mask(ab, aad(sa)->request);
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if (aad(sa)->denied & AA_PTRACE_PERM_MASK) {
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audit_log_format(ab, " denied_mask=");
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audit_ptrace_mask(ab, aad(sa)->denied);
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}
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}
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audit_log_format(ab, " peer=");
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aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer,
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FLAGS_NONE, GFP_ATOMIC);
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}
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/* assumes check for PROFILE_MEDIATES is already done */
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/* TODO: conditionals */
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static int profile_ptrace_perm(struct aa_profile *profile,
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struct aa_label *peer, u32 request,
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struct common_audit_data *sa)
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{
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struct aa_perms perms = { };
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aad(sa)->peer = peer;
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aa_profile_match_label(profile, peer, AA_CLASS_PTRACE, request,
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&perms);
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aa_apply_modes_to_perms(profile, &perms);
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return aa_check_perms(profile, &perms, request, sa, audit_ptrace_cb);
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}
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static int profile_tracee_perm(struct aa_profile *tracee,
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struct aa_label *tracer, u32 request,
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struct common_audit_data *sa)
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{
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if (profile_unconfined(tracee) || unconfined(tracer) ||
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!PROFILE_MEDIATES(tracee, AA_CLASS_PTRACE))
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return 0;
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return profile_ptrace_perm(tracee, tracer, request, sa);
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}
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static int profile_tracer_perm(struct aa_profile *tracer,
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struct aa_label *tracee, u32 request,
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struct common_audit_data *sa)
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{
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if (profile_unconfined(tracer))
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return 0;
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if (PROFILE_MEDIATES(tracer, AA_CLASS_PTRACE))
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return profile_ptrace_perm(tracer, tracee, request, sa);
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/* profile uses the old style capability check for ptrace */
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if (&tracer->label == tracee)
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return 0;
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aad(sa)->label = &tracer->label;
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aad(sa)->peer = tracee;
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aad(sa)->request = 0;
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aad(sa)->error = aa_capable(&tracer->label, CAP_SYS_PTRACE,
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CAP_OPT_NONE);
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return aa_audit(AUDIT_APPARMOR_AUTO, tracer, sa, audit_ptrace_cb);
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}
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/**
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* aa_may_ptrace - test if tracer task can trace the tracee
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* @tracer: label of the task doing the tracing (NOT NULL)
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* @tracee: task label to be traced
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* @request: permission request
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*
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* Returns: %0 else error code if permission denied or error
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*/
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int aa_may_ptrace(struct aa_label *tracer, struct aa_label *tracee,
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u32 request)
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{
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struct aa_profile *profile;
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u32 xrequest = request << PTRACE_PERM_SHIFT;
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DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_PTRACE);
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return xcheck_labels(tracer, tracee, profile,
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profile_tracer_perm(profile, tracee, request, &sa),
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profile_tracee_perm(profile, tracer, xrequest, &sa));
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}
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static inline int map_signal_num(int sig)
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{
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if (sig > SIGRTMAX)
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return SIGUNKNOWN;
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else if (sig >= SIGRTMIN)
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return sig - SIGRTMIN + SIGRT_BASE;
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else if (sig < MAXMAPPED_SIG)
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return sig_map[sig];
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return SIGUNKNOWN;
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}
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/**
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* audit_file_mask - convert mask to permission string
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* @buffer: buffer to write string to (NOT NULL)
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* @mask: permission mask to convert
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*/
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static void audit_signal_mask(struct audit_buffer *ab, u32 mask)
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{
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if (mask & MAY_READ)
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audit_log_string(ab, "receive");
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if (mask & MAY_WRITE)
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audit_log_string(ab, "send");
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}
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/**
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* audit_cb - call back for signal specific audit fields
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* @ab: audit_buffer (NOT NULL)
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* @va: audit struct to audit values of (NOT NULL)
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*/
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static void audit_signal_cb(struct audit_buffer *ab, void *va)
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{
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struct common_audit_data *sa = va;
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if (aad(sa)->request & AA_SIGNAL_PERM_MASK) {
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audit_log_format(ab, " requested_mask=");
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audit_signal_mask(ab, aad(sa)->request);
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if (aad(sa)->denied & AA_SIGNAL_PERM_MASK) {
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audit_log_format(ab, " denied_mask=");
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audit_signal_mask(ab, aad(sa)->denied);
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}
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}
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if (aad(sa)->signal == SIGUNKNOWN)
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audit_log_format(ab, "signal=unknown(%d)",
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aad(sa)->unmappedsig);
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else if (aad(sa)->signal < MAXMAPPED_SIGNAME)
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audit_log_format(ab, " signal=%s", sig_names[aad(sa)->signal]);
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else
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audit_log_format(ab, " signal=rtmin+%d",
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aad(sa)->signal - SIGRT_BASE);
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audit_log_format(ab, " peer=");
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aa_label_xaudit(ab, labels_ns(aad(sa)->label), aad(sa)->peer,
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FLAGS_NONE, GFP_ATOMIC);
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}
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static int profile_signal_perm(struct aa_profile *profile,
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struct aa_label *peer, u32 request,
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struct common_audit_data *sa)
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{
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struct aa_perms perms;
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unsigned int state;
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if (profile_unconfined(profile) ||
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!PROFILE_MEDIATES(profile, AA_CLASS_SIGNAL))
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return 0;
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aad(sa)->peer = peer;
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/* TODO: secondary cache check <profile, profile, perm> */
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state = aa_dfa_next(profile->policy.dfa,
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profile->policy.start[AA_CLASS_SIGNAL],
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aad(sa)->signal);
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aa_label_match(profile, peer, state, false, request, &perms);
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aa_apply_modes_to_perms(profile, &perms);
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return aa_check_perms(profile, &perms, request, sa, audit_signal_cb);
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}
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int aa_may_signal(struct aa_label *sender, struct aa_label *target, int sig)
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{
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struct aa_profile *profile;
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DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_SIGNAL);
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aad(&sa)->signal = map_signal_num(sig);
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aad(&sa)->unmappedsig = sig;
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return xcheck_labels(sender, target, profile,
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profile_signal_perm(profile, target, MAY_WRITE, &sa),
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profile_signal_perm(profile, sender, MAY_READ, &sa));
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}
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