1 | /* $Id: getrawsock.c 106061 2024-09-16 14:03:52Z vboxsync $ */
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2 | /** @file
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3 | * Obtain raw-sockets from a server when debugging unprivileged.
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4 | */
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5 |
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6 | /*
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7 | * Copyright (C) 2013-2024 Oracle and/or its affiliates.
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8 | *
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9 | * This file is part of VirtualBox base platform packages, as
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10 | * available from https://www.virtualbox.org.
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11 | *
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12 | * This program is free software; you can redistribute it and/or
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13 | * modify it under the terms of the GNU General Public License
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14 | * as published by the Free Software Foundation, in version 3 of the
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15 | * License.
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16 | *
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17 | * This program is distributed in the hope that it will be useful, but
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18 | * WITHOUT ANY WARRANTY; without even the implied warranty of
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19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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20 | * General Public License for more details.
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21 | *
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22 | * You should have received a copy of the GNU General Public License
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23 | * along with this program; if not, see <https://www.gnu.org/licenses>.
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24 | *
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25 | * SPDX-License-Identifier: GPL-3.0-only
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26 | */
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27 |
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28 | #include <sys/types.h>
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29 | #include <sys/socket.h>
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30 | #include <sys/un.h>
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31 | #include <netinet/in.h>
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32 | #include <errno.h>
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33 | #include <pwd.h>
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34 | #include <signal.h>
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35 | #include <stdio.h>
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36 | #include <string.h>
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37 | #include <unistd.h>
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38 |
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39 | /* XXX: this should be in a header, but isn't. naughty me. :( */
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40 | int getrawsock(int type);
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41 |
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42 |
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43 | int
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44 | getrawsock(int type)
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45 | {
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46 | struct sockaddr_un sux; /* because solaris */
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47 | struct passwd *pw;
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48 | size_t pathlen;
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49 | int rawsock, server;
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50 | struct msghdr mh;
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51 | struct iovec iov[1];
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52 | char buf[1];
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53 | struct cmsghdr *cmh;
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54 | char cmsg[CMSG_SPACE(sizeof(int))];
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55 | ssize_t nread, nsent;
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56 | int status;
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57 |
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58 | server = -1;
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59 | rawsock = -1;
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60 |
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61 | memset(&sux, 0, sizeof(sux));
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62 | sux.sun_family = AF_UNIX;
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63 |
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64 | if (geteuid() == 0) {
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65 | return -1;
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66 | }
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67 |
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68 | if (type == AF_INET) {
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69 | buf[0] = '4';
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70 | }
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71 | else if (type == AF_INET6) {
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72 | buf[0] = '6';
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73 | }
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74 | else {
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75 | return -1;
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76 | }
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77 |
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78 | errno = 0;
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79 | pw = getpwuid(getuid());
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80 | if (pw == NULL) {
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81 | perror("getpwuid");
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82 | return -1;
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83 | }
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84 |
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85 | pathlen = snprintf(sux.sun_path, sizeof(sux.sun_path),
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86 | "/tmp/.vbox-%s-aux/mkrawsock", pw->pw_name);
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87 | if (pathlen > sizeof(sux.sun_path)) {
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88 | fprintf(stderr, "socket pathname truncated\n");
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89 | return -1;
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90 | }
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91 |
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92 | server = socket(PF_UNIX, SOCK_STREAM, 0);
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93 | if (server < 0) {
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94 | perror("socket");
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95 | return -1;
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96 | }
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97 |
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98 | status = connect(server, (struct sockaddr *)&sux,
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99 | (sizeof(sux) - sizeof(sux.sun_path)
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100 | + strlen(sux.sun_path) + 1));
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101 | if (status < 0) {
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102 | perror(sux.sun_path);
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103 | goto out;
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104 | }
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105 |
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106 | nsent = send(server, buf, 1, 0);
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107 | if (nsent != 1) {
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108 | if (nsent < 0) {
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109 | perror("send");
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110 | }
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111 | else {
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112 | fprintf(stderr, "failed to contact mkrawsock\n");
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113 | }
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114 | goto out;
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115 | }
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116 |
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117 | buf[0] = '\0';
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118 |
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119 | iov[0].iov_base = buf;
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120 | iov[0].iov_len = 1;
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121 |
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122 | memset(&mh, 0, sizeof(mh));
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123 | mh.msg_iov = iov;
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124 | mh.msg_iovlen = 1;
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125 | mh.msg_control = cmsg;
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126 | mh.msg_controllen = sizeof(cmsg);
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127 |
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128 | nread = recvmsg(server, &mh, 0);
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129 | if (nread != 1) {
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130 | if (nread < 0) {
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131 | perror("recvmsg");
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132 | }
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133 | else {
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134 | fprintf(stderr, "EOF from mkrawsock\n");
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135 | }
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136 | goto out;
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137 | }
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138 |
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139 | if ((type == AF_INET && buf[0] != '4')
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140 | || (type == AF_INET6 && buf[0] != '6')
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141 | || mh.msg_controllen == 0)
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142 | {
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143 | goto out;
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144 | }
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145 |
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146 | for (cmh = CMSG_FIRSTHDR(&mh); cmh != NULL; cmh = CMSG_NXTHDR(&mh, cmh)) {
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147 | if ((cmh->cmsg_level == SOL_SOCKET)
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148 | && (cmh->cmsg_type == SCM_RIGHTS)
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149 | && (cmh->cmsg_len == CMSG_LEN(sizeof(rawsock))))
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150 | {
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151 | rawsock = *((int *)CMSG_DATA(cmh));
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152 | break;
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153 | }
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154 | }
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155 |
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156 | out:
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157 | if (server != -1) {
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158 | close(server);
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159 | }
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160 | if (rawsock != -1) {
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161 | printf("%s: got ICMPv%c socket %d\n",
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162 | __func__, type == AF_INET ? '4' : '6', rawsock);
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163 | }
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164 | return rawsock;
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165 | }
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