/*
 * AppArmor security module
 *
 * This file contains AppArmor auditing functions
 *
 * Copyright (C) 1998-2008 Novell/SUSE
 * Copyright 2009-2010 Canonical Ltd.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, version 2 of the
 * License.
 */

#include <linux/audit.h>
#include <linux/socket.h>

#include "include/apparmor.h"
#include "include/audit.h"
#include "include/policy.h"
#include "include/policy_ns.h"
#include "include/secid.h"

const char *const audit_mode_names[] = {
        "normal",
        "quiet_denied",
        "quiet",
        "noquiet",
        "all"
};

static const char *const aa_audit_type[] = {
        "AUDIT",
        "ALLOWED",
        "DENIED",
        "HINT",
        "STATUS",
        "ERROR",
        "KILLED",
        "AUTO"
};

/*
 * Currently AppArmor auditing is fed straight into the audit framework.
 *
 * TODO:
 * netlink interface for complain mode
 * user auditing, - send user auditing to netlink interface
 * system control of whether user audit messages go to system log
 */

/**
 * audit_base - core AppArmor function.
 * @ab: audit buffer to fill (NOT NULL)
 * @ca: audit structure containing data to audit (NOT NULL)
 *
 * Record common AppArmor audit data from @sa
 */
static void audit_pre(struct audit_buffer *ab, void *ca)
{
        struct common_audit_data *sa = ca;

        if (aa_g_audit_header) {
                audit_log_format(ab, "apparmor=\"%s\"",
                                 aa_audit_type[aad(sa)->type]);
        }

        if (aad(sa)->op) {
                audit_log_format(ab, " operation=\"%s\"", aad(sa)->op);
        }

        if (aad(sa)->info) {
                audit_log_format(ab, " info=\"%s\"", aad(sa)->info);
                if (aad(sa)->error)
                        audit_log_format(ab, " error=%d", aad(sa)->error);
        }

        if (aad(sa)->label) {
                struct aa_label *label = aad(sa)->label;

                if (label_isprofile(label)) {
                        struct aa_profile *profile = labels_profile(label);

                        if (profile->ns != root_ns) {
                                audit_log_format(ab, " namespace=");
                                audit_log_untrustedstring(ab,
                                                       profile->ns->base.hname);
                        }
                        audit_log_format(ab, " profile=");
                        audit_log_untrustedstring(ab, profile->base.hname);
                } else {
                        audit_log_format(ab, " label=");
                        aa_label_xaudit(ab, root_ns, label, FLAG_VIEW_SUBNS,
                                        GFP_ATOMIC);
                }
        }

        if (aad(sa)->name) {
                audit_log_format(ab, " name=");
                audit_log_untrustedstring(ab, aad(sa)->name);
        }
}

/**
 * aa_audit_msg - Log a message to the audit subsystem
 * @sa: audit event structure (NOT NULL)
 * @cb: optional callback fn for type specific fields (MAYBE NULL)
 */
void aa_audit_msg(int type, struct common_audit_data *sa,
                  void (*cb) (struct audit_buffer *, void *))
{
        aad(sa)->type = type;
        common_lsm_audit(sa, audit_pre, cb);
}

/**
 * aa_audit - Log a profile based audit event to the audit subsystem
 * @type: audit type for the message
 * @profile: profile to check against (NOT NULL)
 * @sa: audit event (NOT NULL)
 * @cb: optional callback fn for type specific fields (MAYBE NULL)
 *
 * Handle default message switching based off of audit mode flags
 *
 * Returns: error on failure
 */
int aa_audit(int type, struct aa_profile *profile, struct common_audit_data *sa,
             void (*cb) (struct audit_buffer *, void *))
{
        AA_BUG(!profile);

        if (type == AUDIT_APPARMOR_AUTO) {
                if (likely(!aad(sa)->error)) {
                        if (AUDIT_MODE(profile) != AUDIT_ALL)
                                return 0;
                        type = AUDIT_APPARMOR_AUDIT;
                } else if (COMPLAIN_MODE(profile))
                        type = AUDIT_APPARMOR_ALLOWED;
                else
                        type = AUDIT_APPARMOR_DENIED;
        }
        if (AUDIT_MODE(profile) == AUDIT_QUIET ||
            (type == AUDIT_APPARMOR_DENIED &&
             AUDIT_MODE(profile) == AUDIT_QUIET))
                return aad(sa)->error;

        if (KILL_MODE(profile) && type == AUDIT_APPARMOR_DENIED)
                type = AUDIT_APPARMOR_KILL;

        aad(sa)->label = &profile->label;

        aa_audit_msg(type, sa, cb);

        if (aad(sa)->type == AUDIT_APPARMOR_KILL)
                (void)send_sig_info(SIGKILL, NULL,
                        sa->type == LSM_AUDIT_DATA_TASK && sa->u.tsk ?
                                    sa->u.tsk : current);

        if (aad(sa)->type == AUDIT_APPARMOR_ALLOWED)
                return complain_error(aad(sa)->error);

        return aad(sa)->error;
}

struct aa_audit_rule {
        struct aa_label *label;
};

void aa_audit_rule_free(void *vrule)
{
        struct aa_audit_rule *rule = vrule;

        if (rule) {
                if (!IS_ERR(rule->label))
                        aa_put_label(rule->label);
                kfree(rule);
        }
}

int aa_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
{
        struct aa_audit_rule *rule;

        switch (field) {
        case AUDIT_SUBJ_ROLE:
                if (op != Audit_equal && op != Audit_not_equal)
                        return -EINVAL;
                break;
        default:
                return -EINVAL;
        }

        rule = kzalloc(sizeof(struct aa_audit_rule), GFP_KERNEL);

        if (!rule)
                return -ENOMEM;

        /* Currently rules are treated as coming from the root ns */
        rule->label = aa_label_parse(&root_ns->unconfined->label, rulestr,
                                     GFP_KERNEL, true, false);
        if (IS_ERR(rule->label)) {
                aa_audit_rule_free(rule);
                return PTR_ERR(rule->label);
        }

        *vrule = rule;
        return 0;
}

int aa_audit_rule_known(struct audit_krule *rule)
{
        int i;

        for (i = 0; i < rule->field_count; i++) {
                struct audit_field *f = &rule->fields[i];

                switch (f->type) {
                case AUDIT_SUBJ_ROLE:
                        return 1;
                }
        }

        return 0;
}

int aa_audit_rule_match(u32 sid, u32 field, u32 op, void *vrule)
{
        struct aa_audit_rule *rule = vrule;
        struct aa_label *label;
        int found = 0;

        label = aa_secid_to_label(sid);

        if (!label)
                return -ENOENT;

        if (aa_label_is_subset(label, rule->label))
                found = 1;

        switch (field) {
        case AUDIT_SUBJ_ROLE:
                switch (op) {
                case Audit_equal:
                        return found;
                case Audit_not_equal:
                        return !found;
                }
        }
        return 0;
}