blob: 8e7d38be198fd502d3c4df80eb78129be448397c [file] [log] [blame]
/*
* 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 TRACE_AUTH
#include "sysdeps.h"
#include "adb_auth.h"
#include <resolv.h>
#include <stdio.h>
#include <string.h>
#include "cutils/list.h"
#include "cutils/sockets.h"
#include "mincrypt/rsa.h"
#include "mincrypt/sha.h"
#include "adb.h"
#include "fdevent.h"
#include "transport.h"
struct adb_public_key {
struct listnode node;
RSAPublicKey key;
};
static const char *key_paths[] = {
"/adb_keys",
"/data/misc/adb/adb_keys",
NULL
};
static fdevent listener_fde;
static int framework_fd = -1;
static void usb_disconnected(void* unused, atransport* t);
static struct adisconnect usb_disconnect = { usb_disconnected, 0, 0, 0 };
static atransport* usb_transport;
static bool needs_retry = false;
static void read_keys(const char *file, struct listnode *list)
{
FILE *f;
char buf[MAX_PAYLOAD];
char *sep;
int ret;
f = fopen(file, "re");
if (!f) {
D("Can't open '%s'\n", file);
return;
}
while (fgets(buf, sizeof(buf), f)) {
/* Allocate 4 extra bytes to decode the base64 data in-place */
auto key = reinterpret_cast<adb_public_key*>(
calloc(1, sizeof(adb_public_key) + 4));
if (key == nullptr) {
D("Can't malloc key\n");
break;
}
sep = strpbrk(buf, " \t");
if (sep)
*sep = '\0';
ret = __b64_pton(buf, (u_char *)&key->key, sizeof(key->key) + 4);
if (ret != sizeof(key->key)) {
D("%s: Invalid base64 data ret=%d\n", file, ret);
free(key);
continue;
}
if (key->key.len != RSANUMWORDS) {
D("%s: Invalid key len %d\n", file, key->key.len);
free(key);
continue;
}
list_add_tail(list, &key->node);
}
fclose(f);
}
static void free_keys(struct listnode *list)
{
struct listnode *item;
while (!list_empty(list)) {
item = list_head(list);
list_remove(item);
free(node_to_item(item, struct adb_public_key, node));
}
}
static void load_keys(struct listnode *list)
{
const char* path;
const char** paths = key_paths;
struct stat buf;
list_init(list);
while ((path = *paths++)) {
if (!stat(path, &buf)) {
D("Loading keys from '%s'\n", path);
read_keys(path, list);
}
}
}
int adb_auth_generate_token(void *token, size_t token_size)
{
FILE *f;
int ret;
f = fopen("/dev/urandom", "re");
if (!f)
return 0;
ret = fread(token, token_size, 1, f);
fclose(f);
return ret * token_size;
}
int adb_auth_verify(uint8_t* token, uint8_t* sig, int siglen)
{
struct listnode *item;
struct listnode key_list;
int ret = 0;
if (siglen != RSANUMBYTES)
return 0;
load_keys(&key_list);
list_for_each(item, &key_list) {
adb_public_key* key = node_to_item(item, struct adb_public_key, node);
ret = RSA_verify(&key->key, sig, siglen, token, SHA_DIGEST_SIZE);
if (ret)
break;
}
free_keys(&key_list);
return ret;
}
static void usb_disconnected(void* unused, atransport* t)
{
D("USB disconnect\n");
remove_transport_disconnect(usb_transport, &usb_disconnect);
usb_transport = NULL;
needs_retry = false;
}
static void adb_auth_event(int fd, unsigned events, void *data)
{
char response[2];
int ret;
if (events & FDE_READ) {
ret = unix_read(fd, response, sizeof(response));
if (ret <= 0) {
D("Framework disconnect\n");
if (usb_transport)
fdevent_remove(&usb_transport->auth_fde);
framework_fd = -1;
}
else if (ret == 2 && response[0] == 'O' && response[1] == 'K') {
if (usb_transport)
adb_auth_verified(usb_transport);
}
}
}
void adb_auth_confirm_key(unsigned char *key, size_t len, atransport *t)
{
char msg[MAX_PAYLOAD];
int ret;
if (!usb_transport) {
usb_transport = t;
add_transport_disconnect(t, &usb_disconnect);
}
if (framework_fd < 0) {
D("Client not connected\n");
needs_retry = true;
return;
}
if (key[len - 1] != '\0') {
D("Key must be a null-terminated string\n");
return;
}
ret = snprintf(msg, sizeof(msg), "PK%s", key);
if (ret >= (signed)sizeof(msg)) {
D("Key too long. ret=%d", ret);
return;
}
D("Sending '%s'\n", msg);
ret = unix_write(framework_fd, msg, ret);
if (ret < 0) {
D("Failed to write PK, errno=%d\n", errno);
return;
}
fdevent_install(&t->auth_fde, framework_fd, adb_auth_event, t);
fdevent_add(&t->auth_fde, FDE_READ);
}
static void adb_auth_listener(int fd, unsigned events, void *data)
{
struct sockaddr addr;
socklen_t alen;
int s;
alen = sizeof(addr);
s = adb_socket_accept(fd, &addr, &alen);
if (s < 0) {
D("Failed to accept: errno=%d\n", errno);
return;
}
framework_fd = s;
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) {
D("Failed to get adbd socket\n");
return;
}
fcntl(fd, F_SETFD, FD_CLOEXEC);
}
void adbd_auth_init(void) {
int fd = android_get_control_socket("adbd");
if (fd == -1) {
D("Failed to get adbd socket\n");
return;
}
if (listen(fd, 4) == -1) {
D("Failed to listen on '%d'\n", fd);
return;
}
fdevent_install(&listener_fde, fd, adb_auth_listener, NULL);
fdevent_add(&listener_fde, FDE_READ);
}