platform_system_core/logd/auditctl.cpp
Nick Kralevich be5e446791 introduce auditctl and use it to configure SELinux throttling
In an effort to ensure that our development community does not
introduce new code without corresponding SELinux changes, Android
closely monitors the number of SELinux denials which occur during
boot. This monitoring occurs both in treehugger, as well as various
dashboards. If SELinux denials are dropped during early boot, this
could result in non-determinism for the various SELinux treehugger
tests.

Introduce /system/bin/auditctl. This tool, model after
https://linux.die.net/man/8/auditctl , allows for configuring the
throttling rate for the kernel auditing system.

Remove any throttling from early boot. This will hopefully reduce
treehugger flakiness by making denial generation more predictible
during early boot.

Reapply the throttling at boot complete, to avoid denial of service
attacks against the auditing subsystem.

Delete pre-existing unittests for logd / SELinux integration. It's
intended that all throttling decisions be made in the kernel, and
shouldn't be a concern of logd.

Bug: 118815957
Test: Perform an operation which generates lots of SELinux denials,
      and count how many occur before and after the time period.
Change-Id: I6c787dbdd4a28208dc854b543e1727ae92e5eeed
2019-04-09 13:19:08 -07:00

74 lines
2.1 KiB
C++

/*
* Copyright (C) 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <android-base/parseint.h>
#include <error.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "libaudit.h"
static void usage(const char* cmdline) {
fprintf(stderr, "Usage: %s [-r rate]\n", cmdline);
}
static void do_update_rate(uint32_t rate) {
int fd = audit_open();
if (fd == -1) {
error(EXIT_FAILURE, errno, "Unable to open audit socket");
}
int result = audit_rate_limit(fd, rate);
close(fd);
if (result < 0) {
fprintf(stderr, "Can't update audit rate limit: %d\n", result);
exit(EXIT_FAILURE);
}
}
int main(int argc, char* argv[]) {
uint32_t rate = 0;
bool update_rate = false;
int opt;
while ((opt = getopt(argc, argv, "r:")) != -1) {
switch (opt) {
case 'r':
if (!android::base::ParseUint<uint32_t>(optarg, &rate)) {
error(EXIT_FAILURE, errno, "Invalid Rate");
}
update_rate = true;
break;
default: /* '?' */
usage(argv[0]);
exit(EXIT_FAILURE);
}
}
// In the future, we may add other options to auditctl
// so this if statement will expand.
// if (!update_rate && !update_backlog && !update_whatever) ...
if (!update_rate) {
fprintf(stderr, "Nothing to do\n");
usage(argv[0]);
exit(EXIT_FAILURE);
}
if (update_rate) {
do_update_rate(rate);
}
return 0;
}