You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
199 lines
8.1 KiB
199 lines
8.1 KiB
/*
|
|
* 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 <string>
|
|
#include <vector>
|
|
|
|
#include <errno.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
|
|
#define LOG_TAG "StrictController"
|
|
#define LOG_NDEBUG 0
|
|
#include <log/log.h>
|
|
|
|
#include <android-base/stringprintf.h>
|
|
#include <android-base/strings.h>
|
|
|
|
#include "ConnmarkFlags.h"
|
|
#include "NetdConstants.h"
|
|
#include "StrictController.h"
|
|
|
|
auto StrictController::execIptablesRestore = ::execIptablesRestore;
|
|
|
|
const char* StrictController::LOCAL_OUTPUT = "st_OUTPUT";
|
|
const char* StrictController::LOCAL_CLEAR_DETECT = "st_clear_detect";
|
|
const char* StrictController::LOCAL_CLEAR_CAUGHT = "st_clear_caught";
|
|
const char* StrictController::LOCAL_PENALTY_LOG = "st_penalty_log";
|
|
const char* StrictController::LOCAL_PENALTY_REJECT = "st_penalty_reject";
|
|
|
|
using android::base::Join;
|
|
using android::base::StringPrintf;
|
|
|
|
StrictController::StrictController(void) {
|
|
}
|
|
|
|
int StrictController::setupIptablesHooks(void) {
|
|
char connmarkFlagAccept[16];
|
|
char connmarkFlagReject[16];
|
|
char connmarkFlagTestAccept[32];
|
|
char connmarkFlagTestReject[32];
|
|
sprintf(connmarkFlagAccept, "0x%x", ConnmarkFlags::STRICT_RESOLVED_ACCEPT);
|
|
sprintf(connmarkFlagReject, "0x%x", ConnmarkFlags::STRICT_RESOLVED_REJECT);
|
|
sprintf(connmarkFlagTestAccept, "0x%x/0x%x",
|
|
ConnmarkFlags::STRICT_RESOLVED_ACCEPT,
|
|
ConnmarkFlags::STRICT_RESOLVED_ACCEPT);
|
|
sprintf(connmarkFlagTestReject, "0x%x/0x%x",
|
|
ConnmarkFlags::STRICT_RESOLVED_REJECT,
|
|
ConnmarkFlags::STRICT_RESOLVED_REJECT);
|
|
|
|
resetChains();
|
|
|
|
int res = 0;
|
|
std::vector<std::string> v4, v6;
|
|
|
|
#define CMD_V4(...) { auto cmd = StringPrintf(__VA_ARGS__); v4.push_back(cmd); }
|
|
#define CMD_V6(...) { auto cmd = StringPrintf(__VA_ARGS__); v6.push_back(cmd); }
|
|
#define CMD_V4V6(...) { CMD_V4(__VA_ARGS__); CMD_V6(__VA_ARGS__); };
|
|
|
|
CMD_V4V6("*filter");
|
|
|
|
// Chain triggered when cleartext socket detected and penalty is log
|
|
CMD_V4V6("-A %s -j CONNMARK --or-mark %s", LOCAL_PENALTY_LOG, connmarkFlagAccept);
|
|
CMD_V4V6("-A %s -j NFLOG --nflog-group 0", LOCAL_PENALTY_LOG);
|
|
|
|
// Chain triggered when cleartext socket detected and penalty is reject
|
|
CMD_V4V6("-A %s -j CONNMARK --or-mark %s", LOCAL_PENALTY_REJECT, connmarkFlagReject);
|
|
CMD_V4V6("-A %s -j NFLOG --nflog-group 0", LOCAL_PENALTY_REJECT);
|
|
CMD_V4V6("-A %s -j REJECT", LOCAL_PENALTY_REJECT);
|
|
|
|
// We use a high-order mark bit to keep track of connections that we've already resolved.
|
|
// Quickly skip connections that we've already resolved
|
|
CMD_V4V6("-A %s -m connmark --mark %s -j REJECT", LOCAL_CLEAR_DETECT, connmarkFlagTestReject);
|
|
CMD_V4V6("-A %s -m connmark --mark %s -j RETURN", LOCAL_CLEAR_DETECT, connmarkFlagTestAccept);
|
|
|
|
// Look for IPv4 TCP/UDP connections with TLS/DTLS header
|
|
const char *u32;
|
|
u32 = "0>>22&0x3C@ 12>>26&0x3C@ 0&0xFFFF0000=0x16030000 &&"
|
|
"0>>22&0x3C@ 12>>26&0x3C@ 4&0x00FF0000=0x00010000";
|
|
CMD_V4("-A %s -p tcp -m u32 --u32 \"%s\" -j CONNMARK --or-mark %s",
|
|
LOCAL_CLEAR_DETECT, u32, connmarkFlagAccept);
|
|
|
|
u32 = "0>>22&0x3C@ 8&0xFFFF0000=0x16FE0000 &&"
|
|
"0>>22&0x3C@ 20&0x00FF0000=0x00010000";
|
|
CMD_V4("-A %s -p udp -m u32 --u32 \"%s\" -j CONNMARK --or-mark %s",
|
|
LOCAL_CLEAR_DETECT, u32, connmarkFlagAccept);
|
|
|
|
// Look for IPv6 TCP/UDP connections with TLS/DTLS header. The IPv6 header
|
|
// doesn't have an IHL field to shift with, so we have to manually add in
|
|
// the 40-byte offset at every step.
|
|
u32 = "52>>26&0x3C@ 40&0xFFFF0000=0x16030000 &&"
|
|
"52>>26&0x3C@ 44&0x00FF0000=0x00010000";
|
|
CMD_V6("-A %s -p tcp -m u32 --u32 \"%s\" -j CONNMARK --or-mark %s",
|
|
LOCAL_CLEAR_DETECT, u32, connmarkFlagAccept);
|
|
|
|
u32 = "48&0xFFFF0000=0x16FE0000 &&"
|
|
"60&0x00FF0000=0x00010000";
|
|
CMD_V6("-A %s -p udp -m u32 --u32 \"%s\" -j CONNMARK --or-mark %s",
|
|
LOCAL_CLEAR_DETECT, u32, connmarkFlagAccept);
|
|
|
|
// Skip newly classified connections from above
|
|
CMD_V4V6("-A %s -m connmark --mark %s -j RETURN", LOCAL_CLEAR_DETECT, connmarkFlagTestAccept);
|
|
|
|
// Handle TCP/UDP payloads that didn't match TLS/DTLS filters above,
|
|
// which means we've probably found cleartext data. The TCP variant
|
|
// depends on u32 returning false when we try reading into the message
|
|
// body to ignore empty ACK packets.
|
|
u32 = "0>>22&0x3C@ 12>>26&0x3C@ 0&0x0=0x0";
|
|
CMD_V4("-A %s -p tcp -m state --state ESTABLISHED -m u32 --u32 \"%s\" -j %s",
|
|
LOCAL_CLEAR_DETECT, u32, LOCAL_CLEAR_CAUGHT);
|
|
|
|
u32 = "52>>26&0x3C@ 40&0x0=0x0";
|
|
CMD_V6("-A %s -p tcp -m state --state ESTABLISHED -m u32 --u32 \"%s\" -j %s",
|
|
LOCAL_CLEAR_DETECT, u32, LOCAL_CLEAR_CAUGHT);
|
|
|
|
CMD_V4V6("-A %s -p udp -j %s", LOCAL_CLEAR_DETECT, LOCAL_CLEAR_CAUGHT);
|
|
CMD_V4V6("COMMIT\n");
|
|
|
|
res |= execIptablesRestore(V4, Join(v4, '\n'));
|
|
res |= execIptablesRestore(V6, Join(v6, '\n'));
|
|
|
|
#undef CMD_V4
|
|
#undef CMD_V6
|
|
#undef CMD_V4V6
|
|
|
|
return res ? -EREMOTEIO : 0;
|
|
}
|
|
|
|
int StrictController::resetChains(void) {
|
|
// Flush any existing rules
|
|
#define CLEAR_CHAIN(x) StringPrintf(":%s -", (x))
|
|
std::vector<std::string> commandList = {
|
|
"*filter",
|
|
CLEAR_CHAIN(LOCAL_OUTPUT),
|
|
CLEAR_CHAIN(LOCAL_PENALTY_LOG),
|
|
CLEAR_CHAIN(LOCAL_PENALTY_REJECT),
|
|
CLEAR_CHAIN(LOCAL_CLEAR_CAUGHT),
|
|
CLEAR_CHAIN(LOCAL_CLEAR_DETECT),
|
|
"COMMIT\n"
|
|
};
|
|
const std::string commands = Join(commandList, '\n');
|
|
return (execIptablesRestore(V4V6, commands) == 0) ? 0 : -EREMOTEIO;
|
|
#undef CLEAR_CHAIN
|
|
}
|
|
|
|
int StrictController::setUidCleartextPenalty(uid_t uid, StrictPenalty penalty) {
|
|
// When a penalty is set, we don't know what penalty the UID previously had. In order to be able
|
|
// to clear the previous penalty without causing an iptables error by deleting rules that don't
|
|
// exist, put each UID's rules in a chain specific to that UID. That way, the commands we need
|
|
// to run to clear the previous penalty don't depend on what the penalty actually was - all we
|
|
// need to do is clear the chain.
|
|
std::string perUidChain = StringPrintf("st_clear_caught_%u", uid);
|
|
|
|
std::vector<std::string> commands;
|
|
if (penalty == ACCEPT) {
|
|
// Clean up any old rules
|
|
commands = {
|
|
"*filter",
|
|
StringPrintf("-D %s -m owner --uid-owner %d -j %s",
|
|
LOCAL_OUTPUT, uid, LOCAL_CLEAR_DETECT),
|
|
StringPrintf("-D %s -m owner --uid-owner %d -j %s",
|
|
LOCAL_CLEAR_CAUGHT, uid, perUidChain.c_str()),
|
|
StringPrintf("-F %s", perUidChain.c_str()),
|
|
StringPrintf("-X %s", perUidChain.c_str()),
|
|
};
|
|
} else {
|
|
// Always take a detour to investigate this UID
|
|
commands.push_back("*filter");
|
|
commands.push_back(StringPrintf(":%s -", perUidChain.c_str()));
|
|
commands.push_back(StringPrintf("-I %s -m owner --uid-owner %d -j %s",
|
|
LOCAL_OUTPUT, uid, LOCAL_CLEAR_DETECT));
|
|
commands.push_back(StringPrintf("-I %s -m owner --uid-owner %d -j %s",
|
|
LOCAL_CLEAR_CAUGHT, uid, perUidChain.c_str()));
|
|
|
|
if (penalty == LOG) {
|
|
commands.push_back(StringPrintf("-A %s -j %s", perUidChain.c_str(), LOCAL_PENALTY_LOG));
|
|
} else if (penalty == REJECT) {
|
|
commands.push_back(StringPrintf("-A %s -j %s", perUidChain.c_str(),
|
|
LOCAL_PENALTY_REJECT));
|
|
}
|
|
}
|
|
commands.push_back("COMMIT\n");
|
|
|
|
return (execIptablesRestore(V4V6, Join(commands, "\n")) == 0) ? 0 : -EREMOTEIO;
|
|
}
|