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/* $Id: getrawsock.c $ */
/** @file
* Obtain raw-sockets from a server when debugging unprivileged.
*/
/*
* Copyright (C) 2013-2022 Oracle and/or its affiliates.
*
* This file is part of VirtualBox base platform packages, as
* available from https://www.virtualbox.org.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, in version 3 of the
* License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses>.
*
* SPDX-License-Identifier: GPL-3.0-only
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <netinet/in.h>
#include <errno.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
/* XXX: this should be in a header, but isn't. naughty me. :( */
int getrawsock(int type);
int
getrawsock(int type)
{
struct sockaddr_un sux; /* because solaris */
struct passwd *pw;
size_t pathlen;
int rawsock, server;
struct msghdr mh;
struct iovec iov[1];
char buf[1];
struct cmsghdr *cmh;
char cmsg[CMSG_SPACE(sizeof(int))];
ssize_t nread, nsent;
int status;
server = -1;
rawsock = -1;
memset(&sux, 0, sizeof(sux));
sux.sun_family = AF_UNIX;
if (geteuid() == 0) {
return -1;
}
if (type == AF_INET) {
buf[0] = '4';
}
else if (type == AF_INET6) {
buf[0] = '6';
}
else {
return -1;
}
errno = 0;
pw = getpwuid(getuid());
if (pw == NULL) {
perror("getpwuid");
return -1;
}
pathlen = snprintf(sux.sun_path, sizeof(sux.sun_path),
"/tmp/.vbox-%s-aux/mkrawsock", pw->pw_name);
if (pathlen > sizeof(sux.sun_path)) {
fprintf(stderr, "socket pathname truncated\n");
return -1;
}
server = socket(PF_UNIX, SOCK_STREAM, 0);
if (server < 0) {
perror("socket");
return -1;
}
status = connect(server, (struct sockaddr *)&sux,
(sizeof(sux) - sizeof(sux.sun_path)
+ strlen(sux.sun_path) + 1));
if (status < 0) {
perror(sux.sun_path);
goto out;
}
nsent = send(server, buf, 1, 0);
if (nsent != 1) {
if (nsent < 0) {
perror("send");
}
else {
fprintf(stderr, "failed to contact mkrawsock\n");
}
goto out;
}
buf[0] = '\0';
iov[0].iov_base = buf;
iov[0].iov_len = 1;
memset(&mh, 0, sizeof(mh));
mh.msg_iov = iov;
mh.msg_iovlen = 1;
mh.msg_control = cmsg;
mh.msg_controllen = sizeof(cmsg);
nread = recvmsg(server, &mh, 0);
if (nread != 1) {
if (nread < 0) {
perror("recvmsg");
}
else {
fprintf(stderr, "EOF from mkrawsock\n");
}
goto out;
}
if ((type == AF_INET && buf[0] != '4')
|| (type == AF_INET6 && buf[0] != '6')
|| mh.msg_controllen == 0)
{
goto out;
}
for (cmh = CMSG_FIRSTHDR(&mh); cmh != NULL; cmh = CMSG_NXTHDR(&mh, cmh)) {
if ((cmh->cmsg_level == SOL_SOCKET)
&& (cmh->cmsg_type == SCM_RIGHTS)
&& (cmh->cmsg_len == CMSG_LEN(sizeof(rawsock))))
{
rawsock = *((int *)CMSG_DATA(cmh));
break;
}
}
out:
if (server != -1) {
close(server);
}
if (rawsock != -1) {
printf("%s: got ICMPv%c socket %d\n",
__func__, type == AF_INET ? '4' : '6', rawsock);
}
return rawsock;
}
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