blob: 4eb5e83105c4a890fbf356834fb492409816121d [file] [log] [blame]
/*
* Copyright (C) 2014 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 <ctype.h>
#include <endian.h>
#include <errno.h>
#include <limits.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <sys/prctl.h>
#include <sys/uio.h>
#include <syslog.h>
#include <string>
#include <cutils/properties.h>
#include <log/logger.h>
#include <private/android_filesystem_config.h>
#include <private/android_logger.h>
#include "libaudit.h"
#include "LogAudit.h"
#include "LogBuffer.h"
#include "LogKlog.h"
#include "LogReader.h"
#ifndef AUDITD_ENFORCE_INTEGRITY
#define AUDITD_ENFORCE_INTEGRITY false
#endif
#define KMSG_PRIORITY(PRI) \
'<', \
'0' + LOG_MAKEPRI(LOG_AUTH, LOG_PRI(PRI)) / 10, \
'0' + LOG_MAKEPRI(LOG_AUTH, LOG_PRI(PRI)) % 10, \
'>'
LogAudit::LogAudit(LogBuffer *buf, LogReader *reader, int fdDmesg) :
SocketListener(getLogSocket(), false),
logbuf(buf),
reader(reader),
fdDmesg(fdDmesg),
policyLoaded(false),
rebootToSafeMode(false),
initialized(false) {
logToDmesg("start");
}
bool LogAudit::onDataAvailable(SocketClient *cli) {
if (!initialized) {
prctl(PR_SET_NAME, "logd.auditd");
initialized = true;
}
struct audit_message rep;
rep.nlh.nlmsg_type = 0;
rep.nlh.nlmsg_len = 0;
rep.data[0] = '\0';
if (audit_get_reply(cli->getSocket(), &rep, GET_REPLY_BLOCKING, 0) < 0) {
SLOGE("Failed on audit_get_reply with error: %s", strerror(errno));
return false;
}
logPrint("type=%d %.*s",
rep.nlh.nlmsg_type, rep.nlh.nlmsg_len, rep.data);
return true;
}
void LogAudit::logToDmesg(const std::string& str)
{
static const char prefix[] = { KMSG_PRIORITY(LOG_INFO),
'l', 'o', 'g', 'd', '.', 'a', 'u', 'd', 'i', 't', 'd', ':',
' ', '\0' };
std::string message = prefix + str + "\n";
write(fdDmesg, message.c_str(), message.length());
}
std::string LogAudit::getProperty(const std::string& name)
{
char value[PROP_VALUE_MAX] = {0};
property_get(name.c_str(), value, "");
return value;
}
void LogAudit::enforceIntegrity() {
static bool loggedOnce;
bool once = loggedOnce;
loggedOnce = true;
if (!AUDITD_ENFORCE_INTEGRITY) {
if (!once) {
logToDmesg("integrity enforcement suppressed; not rebooting");
}
} else if (rebootToSafeMode) {
if (getProperty("persist.sys.safemode") == "1") {
if (!once) {
logToDmesg("integrity enforcement suppressed; in safe mode");
}
return;
}
logToDmesg("enforcing integrity; rebooting to safe mode");
property_set("persist.sys.safemode", "1");
std::string buildDate = getProperty("ro.build.date.utc");
if (!buildDate.empty()) {
property_set("persist.sys.audit_safemode", buildDate.c_str());
}
property_set("sys.powerctl", "reboot");
} else {
logToDmesg("enforcing integrity: rebooting to recovery");
property_set("sys.powerctl", "reboot,recovery");
}
}
int LogAudit::logPrint(const char *fmt, ...) {
if (fmt == NULL) {
return -EINVAL;
}
va_list args;
char *str = NULL;
va_start(args, fmt);
int rc = vasprintf(&str, fmt, args);
va_end(args);
if (rc < 0) {
return rc;
}
char *cp;
while ((cp = strstr(str, " "))) {
memmove(cp, cp + 1, strlen(cp + 1) + 1);
}
bool loaded = strstr(str, " policy loaded ");
if (loaded) {
if (policyLoaded) {
// SELinux policy changes are not allowed
enforceIntegrity();
} else {
logToDmesg("policy loaded");
policyLoaded = true;
}
}
// Note: The audit log can include untrusted strings, but those containing
// "a control character, unprintable character, double quote mark, or a
// space" are hex encoded. The space character before the search term is
// therefore needed to prevent denial of service. Do not remove the space.
bool permissive = strstr(str, " enforcing=0") ||
strstr(str, " permissive=1");
if (permissive) {
// SELinux in permissive mode is not allowed
enforceIntegrity();
}
bool info = loaded || permissive;
if ((fdDmesg >= 0) && initialized) {
struct iovec iov[3];
static const char log_info[] = { KMSG_PRIORITY(LOG_INFO) };
static const char log_warning[] = { KMSG_PRIORITY(LOG_WARNING) };
iov[0].iov_base = info ? const_cast<char *>(log_info)
: const_cast<char *>(log_warning);
iov[0].iov_len = info ? sizeof(log_info) : sizeof(log_warning);
iov[1].iov_base = str;
iov[1].iov_len = strlen(str);
iov[2].iov_base = const_cast<char *>("\n");
iov[2].iov_len = 1;
writev(fdDmesg, iov, sizeof(iov) / sizeof(iov[0]));
}
pid_t pid = getpid();
pid_t tid = gettid();
uid_t uid = AID_LOGD;
log_time now;
static const char audit_str[] = " audit(";
char *timeptr = strstr(str, audit_str);
if (timeptr
&& ((cp = now.strptime(timeptr + sizeof(audit_str) - 1, "%s.%q")))
&& (*cp == ':')) {
memcpy(timeptr + sizeof(audit_str) - 1, "0.0", 3);
memmove(timeptr + sizeof(audit_str) - 1 + 3, cp, strlen(cp) + 1);
if (!isMonotonic()) {
if (android::isMonotonic(now)) {
LogKlog::convertMonotonicToReal(now);
}
} else {
if (!android::isMonotonic(now)) {
LogKlog::convertRealToMonotonic(now);
}
}
} else if (isMonotonic()) {
now = log_time(CLOCK_MONOTONIC);
} else {
now = log_time(CLOCK_REALTIME);
}
static const char pid_str[] = " pid=";
char *pidptr = strstr(str, pid_str);
if (pidptr && isdigit(pidptr[sizeof(pid_str) - 1])) {
cp = pidptr + sizeof(pid_str) - 1;
pid = 0;
while (isdigit(*cp)) {
pid = (pid * 10) + (*cp - '0');
++cp;
}
tid = pid;
logbuf->lock();
uid = logbuf->pidToUid(pid);
logbuf->unlock();
memmove(pidptr, cp, strlen(cp) + 1);
}
// log to events
size_t l = strnlen(str, LOGGER_ENTRY_MAX_PAYLOAD);
size_t n = l + sizeof(android_log_event_string_t);
bool notify = false;
{ // begin scope for event buffer
uint32_t buffer[(n + sizeof(uint32_t) - 1) / sizeof(uint32_t)];
android_log_event_string_t *event
= reinterpret_cast<android_log_event_string_t *>(buffer);
event->header.tag = htole32(AUDITD_LOG_TAG);
event->type = EVENT_TYPE_STRING;
event->length = htole32(l);
memcpy(event->data, str, l);
rc = logbuf->log(LOG_ID_EVENTS, now, uid, pid, tid,
reinterpret_cast<char *>(event),
(n <= USHRT_MAX) ? (unsigned short) n : USHRT_MAX);
if (rc >= 0) {
notify = true;
}
// end scope for event buffer
}
// log to main
static const char comm_str[] = " comm=\"";
const char *comm = strstr(str, comm_str);
const char *estr = str + strlen(str);
const char *commfree = NULL;
if (comm) {
estr = comm;
comm += sizeof(comm_str) - 1;
} else if (pid == getpid()) {
pid = tid;
comm = "auditd";
} else {
logbuf->lock();
comm = commfree = logbuf->pidToName(pid);
logbuf->unlock();
if (!comm) {
comm = "unknown";
}
}
const char *ecomm = strchr(comm, '"');
if (ecomm) {
++ecomm;
l = ecomm - comm;
} else {
l = strlen(comm) + 1;
ecomm = "";
}
size_t b = estr - str;
if (b > LOGGER_ENTRY_MAX_PAYLOAD) {
b = LOGGER_ENTRY_MAX_PAYLOAD;
}
size_t e = strnlen(ecomm, LOGGER_ENTRY_MAX_PAYLOAD - b);
n = b + e + l + 2;
{ // begin scope for main buffer
char newstr[n];
*newstr = info ? ANDROID_LOG_INFO : ANDROID_LOG_WARN;
strlcpy(newstr + 1, comm, l);
strncpy(newstr + 1 + l, str, b);
strncpy(newstr + 1 + l + b, ecomm, e);
rc = logbuf->log(LOG_ID_MAIN, now, uid, pid, tid, newstr,
(n <= USHRT_MAX) ? (unsigned short) n : USHRT_MAX);
if (rc >= 0) {
notify = true;
}
// end scope for main buffer
}
free(const_cast<char *>(commfree));
free(str);
if (notify) {
reader->notifyNewLog();
if (rc < 0) {
rc = n;
}
}
return rc;
}
int LogAudit::log(char *buf, size_t len) {
char *audit = strstr(buf, " audit(");
if (!audit || (audit >= &buf[len])) {
return 0;
}
*audit = '\0';
int rc;
char *type = strstr(buf, "type=");
if (type && (type < &buf[len])) {
rc = logPrint("%s %s", type, audit + 1);
} else {
rc = logPrint("%s", audit + 1);
}
*audit = ' ';
return rc;
}
int LogAudit::getLogSocket() {
int fd = audit_open();
if (fd < 0) {
return fd;
}
if (audit_setup(fd, getpid()) < 0) {
audit_close(fd);
fd = -1;
}
return fd;
}