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
socket_peer_is_trusted(int fd __android_unused)46 bool 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
socket_close(int sock)66 int socket_close(int sock) {
67 return close(sock);
68 }
69
socket_set_receive_timeout(cutils_socket_t sock,int timeout_ms)70 int 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
socket_send_buffers(cutils_socket_t sock,const cutils_socket_buffer_t * buffers,size_t num_buffers)77 ssize_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
android_get_control_socket(const char * name)96 int 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