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/*
* Copyright (C) 2012 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.
*/
#define TRACE_TAG AUTH
#include "adb.h"
#include "adb_auth.h"
#include "fdevent.h"
#include "sysdeps.h"
#include "transport.h"
#include <resolv.h>
#include <stdio.h>
#include <string.h>
#include <memory>
#include <android-base/file.h>
#include <android-base/strings.h>
#include <crypto_utils/android_pubkey.h>
#include <openssl/obj_mac.h>
#include <openssl/rsa.h>
#include <openssl/sha.h>
static fdevent listener_fde;
static fdevent framework_fde;
static int framework_fd = -1;
static void usb_disconnected(void* unused, atransport* t);
static struct adisconnect usb_disconnect = { usb_disconnected, nullptr};
static atransport* usb_transport;
static bool needs_retry = false;
bool auth_required = true;
bool adbd_auth_verify(const char* token, size_t token_size, const char* sig, int sig_len) {
static constexpr const char* key_paths[] = { "/adb_keys", "/data/misc/adb/adb_keys", nullptr };
for (const auto& path : key_paths) {
if (access(path, R_OK) == 0) {
LOG(INFO) << "Loading keys from " << path;
std::string content;
if (!android::base::ReadFileToString(path, &content)) {
PLOG(ERROR) << "Couldn't read " << path;
continue;
}
for (const auto& line : android::base::Split(content, "\n")) {
// TODO: do we really have to support both ' ' and '\t'?
char* sep = strpbrk(const_cast<char*>(line.c_str()), " \t");
if (sep) *sep = '\0';
// b64_pton requires one additional byte in the target buffer for
// decoding to succeed. See http://b/28035006 for details.
uint8_t keybuf[ANDROID_PUBKEY_ENCODED_SIZE + 1];
if (__b64_pton(line.c_str(), keybuf, sizeof(keybuf)) != ANDROID_PUBKEY_ENCODED_SIZE) {
LOG(ERROR) << "Invalid base64 key " << line.c_str() << " in " << path;
continue;
}
RSA* key = nullptr;
if (!android_pubkey_decode(keybuf, ANDROID_PUBKEY_ENCODED_SIZE, &key)) {
LOG(ERROR) << "Failed to parse key " << line.c_str() << " in " << path;
continue;
}
bool verified =
(RSA_verify(NID_sha1, reinterpret_cast<const uint8_t*>(token), token_size,
reinterpret_cast<const uint8_t*>(sig), sig_len, key) == 1);
RSA_free(key);
if (verified) return true;
}
}
}
return false;
}
static bool adbd_auth_generate_token(void* token, size_t token_size) {
FILE* fp = fopen("/dev/urandom", "re");
if (!fp) return false;
bool okay = (fread(token, token_size, 1, fp) == 1);
fclose(fp);
return okay;
}
static void usb_disconnected(void* unused, atransport* t) {
LOG(INFO) << "USB disconnect";
usb_transport = NULL;
needs_retry = false;
}
static void framework_disconnected() {
LOG(INFO) << "Framework disconnect";
fdevent_remove(&framework_fde);
framework_fd = -1;
}
static void adbd_auth_event(int fd, unsigned events, void*) {
if (events & FDE_READ) {
char response[2];
int ret = unix_read(fd, response, sizeof(response));
if (ret <= 0) {
framework_disconnected();
} else if (ret == 2 && response[0] == 'O' && response[1] == 'K') {
if (usb_transport) {
adbd_auth_verified(usb_transport);
}
}
}
}
void adbd_auth_confirm_key(const char* key, size_t len, atransport* t) {
if (!usb_transport) {
usb_transport = t;
t->AddDisconnect(&usb_disconnect);
}
if (framework_fd < 0) {
LOG(ERROR) << "Client not connected";
needs_retry = true;
return;
}
if (key[len - 1] != '\0') {
LOG(ERROR) << "Key must be a null-terminated string";
return;
}
char msg[MAX_PAYLOAD_V1];
int msg_len = snprintf(msg, sizeof(msg), "PK%s", key);
if (msg_len >= static_cast<int>(sizeof(msg))) {
LOG(ERROR) << "Key too long (" << msg_len << ")";
return;
}
LOG(DEBUG) << "Sending '" << msg << "'";
if (unix_write(framework_fd, msg, msg_len) == -1) {
PLOG(ERROR) << "Failed to write PK";
return;
}
}
static void adbd_auth_listener(int fd, unsigned events, void* data) {
int s = adb_socket_accept(fd, nullptr, nullptr);
if (s < 0) {
PLOG(ERROR) << "Failed to accept";
return;
}
if (framework_fd >= 0) {
LOG(WARNING) << "adb received framework auth socket connection again";
framework_disconnected();
}
framework_fd = s;
fdevent_install(&framework_fde, framework_fd, adbd_auth_event, nullptr);
fdevent_add(&framework_fde, FDE_READ);
if (needs_retry) {
needs_retry = false;
send_auth_request(usb_transport);
}
}
void adbd_cloexec_auth_socket() {
int fd = android_get_control_socket("adbd");
if (fd == -1) {
PLOG(ERROR) << "Failed to get adbd socket";
return;
}
fcntl(fd, F_SETFD, FD_CLOEXEC);
}
void adbd_auth_init(void) {
int fd = android_get_control_socket("adbd");
if (fd == -1) {
PLOG(ERROR) << "Failed to get adbd socket";
return;
}
if (listen(fd, 4) == -1) {
PLOG(ERROR) << "Failed to listen on '" << fd << "'";
return;
}
fdevent_install(&listener_fde, fd, adbd_auth_listener, NULL);
fdevent_add(&listener_fde, FDE_READ);
}
void send_auth_request(atransport* t) {
LOG(INFO) << "Calling send_auth_request...";
if (!adbd_auth_generate_token(t->token, sizeof(t->token))) {
PLOG(ERROR) << "Error generating token";
return;
}
apacket* p = get_apacket();
memcpy(p->data, t->token, sizeof(t->token));
p->msg.command = A_AUTH;
p->msg.arg0 = ADB_AUTH_TOKEN;
p->msg.data_length = sizeof(t->token);
send_packet(p, t);
}
void adbd_auth_verified(atransport *t)
{
handle_online(t);
send_connect(t);
}
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