1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#define LOG_TAG "socket-unix"
18
19#include <stdio.h>
20#include <stdlib.h>
21#include <string.h>
22#include <sys/socket.h>
23#include <sys/uio.h>
24#include <sys/un.h>
25#include <time.h>
26#include <unistd.h>
27
28#include <cutils/android_get_control_file.h>
29#include <cutils/sockets.h>
30#include <log/log.h>
31
32#include "android_get_control_env.h"
33
34#ifndef TEMP_FAILURE_RETRY
35#define TEMP_FAILURE_RETRY(exp) (exp) // KISS implementation
36#endif
37
38#if defined(__ANDROID__)
39/* For the socket trust (credentials) check */
40#include <private/android_filesystem_config.h>
41#define __android_unused
42#else
43#define __android_unused __attribute__((__unused__))
44#endif
45
46bool socket_peer_is_trusted(int fd __android_unused) {
47#if defined(__ANDROID__)
48    ucred cr;
49    socklen_t len = sizeof(cr);
50    int n = getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &cr, &len);
51
52    if (n != 0) {
53        ALOGE("could not get socket credentials: %s\n", strerror(errno));
54        return false;
55    }
56
57    if ((cr.uid != AID_ROOT) && (cr.uid != AID_SHELL)) {
58        ALOGE("untrusted userid on other end of socket: userid %d\n", cr.uid);
59        return false;
60    }
61#endif
62
63    return true;
64}
65
66int socket_close(int sock) {
67    return close(sock);
68}
69
70int socket_set_receive_timeout(cutils_socket_t sock, int timeout_ms) {
71    timeval tv;
72    tv.tv_sec = timeout_ms / 1000;
73    tv.tv_usec = (timeout_ms % 1000) * 1000;
74    return setsockopt(sock, SOL_SOCKET, SO_RCVTIMEO, &tv, sizeof(tv));
75}
76
77ssize_t socket_send_buffers(cutils_socket_t sock,
78                            const cutils_socket_buffer_t* buffers,
79                            size_t num_buffers) {
80    if (num_buffers > SOCKET_SEND_BUFFERS_MAX_BUFFERS) {
81        return -1;
82    }
83
84    iovec iovec_buffers[SOCKET_SEND_BUFFERS_MAX_BUFFERS];
85    for (size_t i = 0; i < num_buffers; ++i) {
86        // It's safe to cast away const here; iovec declares non-const
87        // void* because it's used for both send and receive, but since
88        // we're only sending, the data won't be modified.
89        iovec_buffers[i].iov_base = const_cast<void*>(buffers[i].data);
90        iovec_buffers[i].iov_len = buffers[i].length;
91    }
92
93    return writev(sock, iovec_buffers, num_buffers);
94}
95
96int android_get_control_socket(const char* name) {
97    int fd = __android_get_control_from_env(ANDROID_SOCKET_ENV_PREFIX, name);
98
99    if (fd < 0) return fd;
100
101    // Compare to UNIX domain socket name, must match!
102    struct sockaddr_un addr;
103    socklen_t addrlen = sizeof(addr);
104    int ret = TEMP_FAILURE_RETRY(getsockname(fd, (struct sockaddr *)&addr, &addrlen));
105    if (ret < 0) return -1;
106    char *path = NULL;
107    if (asprintf(&path, ANDROID_SOCKET_DIR "/%s", name) < 0) return -1;
108    if (!path) return -1;
109    int cmp = strcmp(addr.sun_path, path);
110    free(path);
111    if (cmp != 0) return -1;
112
113    // It is what we think it is
114    return fd;
115}
116