Re: [syzbot] [net?] possible deadlock in team_port_change_check (2)

From: xingwei lee
Date: Sun Mar 03 2024 - 03:40:12 EST


Hello, I found a more stable reproducer

=* repro.txt =*
r0 = socket$netlink(0x10, 0x3, 0x0)
writev(r0, &(0x7f0000000040)=[{&(0x7f0000000080)="3900000013000b4600bb65e1c3e4fffff9ffff7f37000000560000022500000019000a001000000007fd17e5ffff080004000000000000000a",
0x39}], 0x1)
r1 = socket$netlink(0x10, 0x3, 0x0)
writev(r1, &(0x7f0000000040)=[{&(0x7f0000000080)="3900000013000b4600bb65e1c3e4ffff0100000036000000560000022500000019000a001000000007fd17e5ffff080004000000000000000a",
0x39}], 0x1)

=* repro.c =*
#define _GNU_SOURCE

#include <arpa/inet.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <netinet/in.h>
#include <sched.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/prctl.h>
#include <sys/resource.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/wait.h>
#include <unistd.h>

#include <linux/capability.h>
#include <linux/genetlink.h>
#include <linux/if_addr.h>
#include <linux/if_ether.h>
#include <linux/if_link.h>
#include <linux/if_tun.h>
#include <linux/in6.h>
#include <linux/ip.h>
#include <linux/neighbour.h>
#include <linux/net.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/tcp.h>
#include <linux/veth.h>

static unsigned long long procid;

static bool write_file(const char* file, const char* what, ...) {
char buf[1024];
va_list args;
va_start(args, what);
vsnprintf(buf, sizeof(buf), what, args);
va_end(args);
buf[sizeof(buf) - 1] = 0;
int len = strlen(buf);
int fd = open(file, O_WRONLY | O_CLOEXEC);
if (fd == -1)
return false;
if (write(fd, buf, len) != len) {
int err = errno;
close(fd);
errno = err;
return false;
}
close(fd);
return true;
}

struct nlmsg {
char* pos;
int nesting;
struct nlattr* nested[8];
char buf[4096];
};

static void netlink_init(struct nlmsg* nlmsg,
int typ,
int flags,
const void* data,
int size) {
memset(nlmsg, 0, sizeof(*nlmsg));
struct nlmsghdr* hdr = (struct nlmsghdr*)nlmsg->buf;
hdr->nlmsg_type = typ;
hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | flags;
memcpy(hdr + 1, data, size);
nlmsg->pos = (char*)(hdr + 1) + NLMSG_ALIGN(size);
}

static void netlink_attr(struct nlmsg* nlmsg,
int typ,
const void* data,
int size) {
struct nlattr* attr = (struct nlattr*)nlmsg->pos;
attr->nla_len = sizeof(*attr) + size;
attr->nla_type = typ;
if (size > 0)
memcpy(attr + 1, data, size);
nlmsg->pos += NLMSG_ALIGN(attr->nla_len);
}

static void netlink_nest(struct nlmsg* nlmsg, int typ) {
struct nlattr* attr = (struct nlattr*)nlmsg->pos;
attr->nla_type = typ;
nlmsg->pos += sizeof(*attr);
nlmsg->nested[nlmsg->nesting++] = attr;
}

static void netlink_done(struct nlmsg* nlmsg) {
struct nlattr* attr = nlmsg->nested[--nlmsg->nesting];
attr->nla_len = nlmsg->pos - (char*)attr;
}

static int netlink_send_ext(struct nlmsg* nlmsg,
int sock,
uint16_t reply_type,
int* reply_len,
bool dofail) {
if (nlmsg->pos > nlmsg->buf + sizeof(nlmsg->buf) || nlmsg->nesting)
exit(1);
struct nlmsghdr* hdr = (struct nlmsghdr*)nlmsg->buf;
hdr->nlmsg_len = nlmsg->pos - nlmsg->buf;
struct sockaddr_nl addr;
memset(&addr, 0, sizeof(addr));
addr.nl_family = AF_NETLINK;
ssize_t n = sendto(sock, nlmsg->buf, hdr->nlmsg_len, 0,
(struct sockaddr*)&addr, sizeof(addr));
if (n != (ssize_t)hdr->nlmsg_len) {
if (dofail)
exit(1);
return -1;
}
n = recv(sock, nlmsg->buf, sizeof(nlmsg->buf), 0);
if (reply_len)
*reply_len = 0;
if (n < 0) {
if (dofail)
exit(1);
return -1;
}
if (n < (ssize_t)sizeof(struct nlmsghdr)) {
errno = EINVAL;
if (dofail)
exit(1);
return -1;
}
if (hdr->nlmsg_type == NLMSG_DONE)
return 0;
if (reply_len && hdr->nlmsg_type == reply_type) {
*reply_len = n;
return 0;
}
if (n < (ssize_t)(sizeof(struct nlmsghdr) + sizeof(struct nlmsgerr))) {
errno = EINVAL;
if (dofail)
exit(1);
return -1;
}
if (hdr->nlmsg_type != NLMSG_ERROR) {
errno = EINVAL;
if (dofail)
exit(1);
return -1;
}
errno = -((struct nlmsgerr*)(hdr + 1))->error;
return -errno;
}

static int netlink_send(struct nlmsg* nlmsg, int sock) {
return netlink_send_ext(nlmsg, sock, 0, NULL, true);
}

static int netlink_query_family_id(struct nlmsg* nlmsg,
int sock,
const char* family_name,
bool dofail) {
struct genlmsghdr genlhdr;
memset(&genlhdr, 0, sizeof(genlhdr));
genlhdr.cmd = CTRL_CMD_GETFAMILY;
netlink_init(nlmsg, GENL_ID_CTRL, 0, &genlhdr, sizeof(genlhdr));
netlink_attr(nlmsg, CTRL_ATTR_FAMILY_NAME, family_name,
strnlen(family_name, GENL_NAMSIZ - 1) + 1);
int n = 0;
int err = netlink_send_ext(nlmsg, sock, GENL_ID_CTRL, &n, dofail);
if (err < 0) {
return -1;
}
uint16_t id = 0;
struct nlattr* attr = (struct nlattr*)(nlmsg->buf + NLMSG_HDRLEN +
NLMSG_ALIGN(sizeof(genlhdr)));
for (; (char*)attr < nlmsg->buf + n;
attr = (struct nlattr*)((char*)attr + NLMSG_ALIGN(attr->nla_len))) {
if (attr->nla_type == CTRL_ATTR_FAMILY_ID) {
id = *(uint16_t*)(attr + 1);
break;
}
}
if (!id) {
errno = EINVAL;
return -1;
}
recv(sock, nlmsg->buf, sizeof(nlmsg->buf), 0);
return id;
}

static int netlink_next_msg(struct nlmsg* nlmsg,
unsigned int offset,
unsigned int total_len) {
struct nlmsghdr* hdr = (struct nlmsghdr*)(nlmsg->buf + offset);
if (offset == total_len || offset + hdr->nlmsg_len > total_len)
return -1;
return hdr->nlmsg_len;
}

static void netlink_add_device_impl(struct nlmsg* nlmsg,
const char* type,
const char* name,
bool up) {
struct ifinfomsg hdr;
memset(&hdr, 0, sizeof(hdr));
if (up)
hdr.ifi_flags = hdr.ifi_change = IFF_UP;
netlink_init(nlmsg, RTM_NEWLINK, NLM_F_EXCL | NLM_F_CREATE, &hdr,
sizeof(hdr));
if (name)
netlink_attr(nlmsg, IFLA_IFNAME, name, strlen(name));
netlink_nest(nlmsg, IFLA_LINKINFO);
netlink_attr(nlmsg, IFLA_INFO_KIND, type, strlen(type));
}

static void netlink_add_device(struct nlmsg* nlmsg,
int sock,
const char* type,
const char* name) {
netlink_add_device_impl(nlmsg, type, name, false);
netlink_done(nlmsg);
int err = netlink_send(nlmsg, sock);
if (err < 0) {
}
}

static void netlink_add_veth(struct nlmsg* nlmsg,
int sock,
const char* name,
const char* peer) {
netlink_add_device_impl(nlmsg, "veth", name, false);
netlink_nest(nlmsg, IFLA_INFO_DATA);
netlink_nest(nlmsg, VETH_INFO_PEER);
nlmsg->pos += sizeof(struct ifinfomsg);
netlink_attr(nlmsg, IFLA_IFNAME, peer, strlen(peer));
netlink_done(nlmsg);
netlink_done(nlmsg);
netlink_done(nlmsg);
int err = netlink_send(nlmsg, sock);
if (err < 0) {
}
}

static void netlink_add_xfrm(struct nlmsg* nlmsg, int sock, const char* name) {
netlink_add_device_impl(nlmsg, "xfrm", name, true);
netlink_nest(nlmsg, IFLA_INFO_DATA);
int if_id = 1;
netlink_attr(nlmsg, 2, &if_id, sizeof(if_id));
netlink_done(nlmsg);
netlink_done(nlmsg);
int err = netlink_send(nlmsg, sock);
if (err < 0) {
}
}

static void netlink_add_hsr(struct nlmsg* nlmsg,
int sock,
const char* name,
const char* slave1,
const char* slave2) {
netlink_add_device_impl(nlmsg, "hsr", name, false);
netlink_nest(nlmsg, IFLA_INFO_DATA);
int ifindex1 = if_nametoindex(slave1);
netlink_attr(nlmsg, IFLA_HSR_SLAVE1, &ifindex1, sizeof(ifindex1));
int ifindex2 = if_nametoindex(slave2);
netlink_attr(nlmsg, IFLA_HSR_SLAVE2, &ifindex2, sizeof(ifindex2));
netlink_done(nlmsg);
netlink_done(nlmsg);
int err = netlink_send(nlmsg, sock);
if (err < 0) {
}
}

static void netlink_add_linked(struct nlmsg* nlmsg,
int sock,
const char* type,
const char* name,
const char* link) {
netlink_add_device_impl(nlmsg, type, name, false);
netlink_done(nlmsg);
int ifindex = if_nametoindex(link);
netlink_attr(nlmsg, IFLA_LINK, &ifindex, sizeof(ifindex));
int err = netlink_send(nlmsg, sock);
if (err < 0) {
}
}

static void netlink_add_vlan(struct nlmsg* nlmsg,
int sock,
const char* name,
const char* link,
uint16_t id,
uint16_t proto) {
netlink_add_device_impl(nlmsg, "vlan", name, false);
netlink_nest(nlmsg, IFLA_INFO_DATA);
netlink_attr(nlmsg, IFLA_VLAN_ID, &id, sizeof(id));
netlink_attr(nlmsg, IFLA_VLAN_PROTOCOL, &proto, sizeof(proto));
netlink_done(nlmsg);
netlink_done(nlmsg);
int ifindex = if_nametoindex(link);
netlink_attr(nlmsg, IFLA_LINK, &ifindex, sizeof(ifindex));
int err = netlink_send(nlmsg, sock);
if (err < 0) {
}
}

static void netlink_add_macvlan(struct nlmsg* nlmsg,
int sock,
const char* name,
const char* link) {
netlink_add_device_impl(nlmsg, "macvlan", name, false);
netlink_nest(nlmsg, IFLA_INFO_DATA);
uint32_t mode = MACVLAN_MODE_BRIDGE;
netlink_attr(nlmsg, IFLA_MACVLAN_MODE, &mode, sizeof(mode));
netlink_done(nlmsg);
netlink_done(nlmsg);
int ifindex = if_nametoindex(link);
netlink_attr(nlmsg, IFLA_LINK, &ifindex, sizeof(ifindex));
int err = netlink_send(nlmsg, sock);
if (err < 0) {
}
}

static void netlink_add_geneve(struct nlmsg* nlmsg,
int sock,
const char* name,
uint32_t vni,
struct in_addr* addr4,
struct in6_addr* addr6) {
netlink_add_device_impl(nlmsg, "geneve", name, false);
netlink_nest(nlmsg, IFLA_INFO_DATA);
netlink_attr(nlmsg, IFLA_GENEVE_ID, &vni, sizeof(vni));
if (addr4)
netlink_attr(nlmsg, IFLA_GENEVE_REMOTE, addr4, sizeof(*addr4));
if (addr6)
netlink_attr(nlmsg, IFLA_GENEVE_REMOTE6, addr6, sizeof(*addr6));
netlink_done(nlmsg);
netlink_done(nlmsg);
int err = netlink_send(nlmsg, sock);
if (err < 0) {
}
}

#define IFLA_IPVLAN_FLAGS 2
#define IPVLAN_MODE_L3S 2
#undef IPVLAN_F_VEPA
#define IPVLAN_F_VEPA 2

static void netlink_add_ipvlan(struct nlmsg* nlmsg,
int sock,
const char* name,
const char* link,
uint16_t mode,
uint16_t flags) {
netlink_add_device_impl(nlmsg, "ipvlan", name, false);
netlink_nest(nlmsg, IFLA_INFO_DATA);
netlink_attr(nlmsg, IFLA_IPVLAN_MODE, &mode, sizeof(mode));
netlink_attr(nlmsg, IFLA_IPVLAN_FLAGS, &flags, sizeof(flags));
netlink_done(nlmsg);
netlink_done(nlmsg);
int ifindex = if_nametoindex(link);
netlink_attr(nlmsg, IFLA_LINK, &ifindex, sizeof(ifindex));
int err = netlink_send(nlmsg, sock);
if (err < 0) {
}
}

static void netlink_device_change(struct nlmsg* nlmsg,
int sock,
const char* name,
bool up,
const char* master,
const void* mac,
int macsize,
const char* new_name) {
struct ifinfomsg hdr;
memset(&hdr, 0, sizeof(hdr));
if (up)
hdr.ifi_flags = hdr.ifi_change = IFF_UP;
hdr.ifi_index = if_nametoindex(name);
netlink_init(nlmsg, RTM_NEWLINK, 0, &hdr, sizeof(hdr));
if (new_name)
netlink_attr(nlmsg, IFLA_IFNAME, new_name, strlen(new_name));
if (master) {
int ifindex = if_nametoindex(master);
netlink_attr(nlmsg, IFLA_MASTER, &ifindex, sizeof(ifindex));
}
if (macsize)
netlink_attr(nlmsg, IFLA_ADDRESS, mac, macsize);
int err = netlink_send(nlmsg, sock);
if (err < 0) {
}
}

static int netlink_add_addr(struct nlmsg* nlmsg,
int sock,
const char* dev,
const void* addr,
int addrsize) {
struct ifaddrmsg hdr;
memset(&hdr, 0, sizeof(hdr));
hdr.ifa_family = addrsize == 4 ? AF_INET : AF_INET6;
hdr.ifa_prefixlen = addrsize == 4 ? 24 : 120;
hdr.ifa_scope = RT_SCOPE_UNIVERSE;
hdr.ifa_index = if_nametoindex(dev);
netlink_init(nlmsg, RTM_NEWADDR, NLM_F_CREATE | NLM_F_REPLACE, &hdr,
sizeof(hdr));
netlink_attr(nlmsg, IFA_LOCAL, addr, addrsize);
netlink_attr(nlmsg, IFA_ADDRESS, addr, addrsize);
return netlink_send(nlmsg, sock);
}

static void netlink_add_addr4(struct nlmsg* nlmsg,
int sock,
const char* dev,
const char* addr) {
struct in_addr in_addr;
inet_pton(AF_INET, addr, &in_addr);
int err = netlink_add_addr(nlmsg, sock, dev, &in_addr, sizeof(in_addr));
if (err < 0) {
}
}

static void netlink_add_addr6(struct nlmsg* nlmsg,
int sock,
const char* dev,
const char* addr) {
struct in6_addr in6_addr;
inet_pton(AF_INET6, addr, &in6_addr);
int err = netlink_add_addr(nlmsg, sock, dev, &in6_addr, sizeof(in6_addr));
if (err < 0) {
}
}

static void netlink_add_neigh(struct nlmsg* nlmsg,
int sock,
const char* name,
const void* addr,
int addrsize,
const void* mac,
int macsize) {
struct ndmsg hdr;
memset(&hdr, 0, sizeof(hdr));
hdr.ndm_family = addrsize == 4 ? AF_INET : AF_INET6;
hdr.ndm_ifindex = if_nametoindex(name);
hdr.ndm_state = NUD_PERMANENT;
netlink_init(nlmsg, RTM_NEWNEIGH, NLM_F_EXCL | NLM_F_CREATE, &hdr,
sizeof(hdr));
netlink_attr(nlmsg, NDA_DST, addr, addrsize);
netlink_attr(nlmsg, NDA_LLADDR, mac, macsize);
int err = netlink_send(nlmsg, sock);
if (err < 0) {
}
}

static struct nlmsg nlmsg;

static int tunfd = -1;

#define TUN_IFACE "syz_tun"
#define LOCAL_MAC 0xaaaaaaaaaaaa
#define REMOTE_MAC 0xaaaaaaaaaabb
#define LOCAL_IPV4 "172.20.20.170"
#define REMOTE_IPV4 "172.20.20.187"
#define LOCAL_IPV6 "fe80::aa"
#define REMOTE_IPV6 "fe80::bb"

#define IFF_NAPI 0x0010

static void initialize_tun(void) {
tunfd = open("/dev/net/tun", O_RDWR | O_NONBLOCK);
if (tunfd == -1) {
printf("tun: can't open /dev/net/tun: please enable CONFIG_TUN=y\n");
printf("otherwise fuzzing or reproducing might not work as intended\n");
return;
}
const int kTunFd = 200;
if (dup2(tunfd, kTunFd) < 0)
exit(1);
close(tunfd);
tunfd = kTunFd;
struct ifreq ifr;
memset(&ifr, 0, sizeof(ifr));
strncpy(ifr.ifr_name, TUN_IFACE, IFNAMSIZ);
ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0) {
exit(1);
}
char sysctl[64];
sprintf(sysctl, "/proc/sys/net/ipv6/conf/%s/accept_dad", TUN_IFACE);
write_file(sysctl, "0");
sprintf(sysctl, "/proc/sys/net/ipv6/conf/%s/router_solicitations", TUN_IFACE);
write_file(sysctl, "0");
int sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (sock == -1)
exit(1);
netlink_add_addr4(&nlmsg, sock, TUN_IFACE, LOCAL_IPV4);
netlink_add_addr6(&nlmsg, sock, TUN_IFACE, LOCAL_IPV6);
uint64_t macaddr = REMOTE_MAC;
struct in_addr in_addr;
inet_pton(AF_INET, REMOTE_IPV4, &in_addr);
netlink_add_neigh(&nlmsg, sock, TUN_IFACE, &in_addr, sizeof(in_addr),
&macaddr, ETH_ALEN);
struct in6_addr in6_addr;
inet_pton(AF_INET6, REMOTE_IPV6, &in6_addr);
netlink_add_neigh(&nlmsg, sock, TUN_IFACE, &in6_addr, sizeof(in6_addr),
&macaddr, ETH_ALEN);
macaddr = LOCAL_MAC;
netlink_device_change(&nlmsg, sock, TUN_IFACE, true, 0, &macaddr, ETH_ALEN,
NULL);
close(sock);
}

#define DEVLINK_FAMILY_NAME "devlink"

#define DEVLINK_CMD_PORT_GET 5
#define DEVLINK_ATTR_BUS_NAME 1
#define DEVLINK_ATTR_DEV_NAME 2
#define DEVLINK_ATTR_NETDEV_NAME 7

static struct nlmsg nlmsg2;

static void initialize_devlink_ports(const char* bus_name,
const char* dev_name,
const char* netdev_prefix) {
struct genlmsghdr genlhdr;
int len, total_len, id, err, offset;
uint16_t netdev_index;
int sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC);
if (sock == -1)
exit(1);
int rtsock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (rtsock == -1)
exit(1);
id = netlink_query_family_id(&nlmsg, sock, DEVLINK_FAMILY_NAME, true);
if (id == -1)
goto error;
memset(&genlhdr, 0, sizeof(genlhdr));
genlhdr.cmd = DEVLINK_CMD_PORT_GET;
netlink_init(&nlmsg, id, NLM_F_DUMP, &genlhdr, sizeof(genlhdr));
netlink_attr(&nlmsg, DEVLINK_ATTR_BUS_NAME, bus_name, strlen(bus_name) + 1);
netlink_attr(&nlmsg, DEVLINK_ATTR_DEV_NAME, dev_name, strlen(dev_name) + 1);
err = netlink_send_ext(&nlmsg, sock, id, &total_len, true);
if (err < 0) {
goto error;
}
offset = 0;
netdev_index = 0;
while ((len = netlink_next_msg(&nlmsg, offset, total_len)) != -1) {
struct nlattr* attr = (struct nlattr*)(nlmsg.buf + offset + NLMSG_HDRLEN +
NLMSG_ALIGN(sizeof(genlhdr)));
for (; (char*)attr < nlmsg.buf + offset + len;
attr = (struct nlattr*)((char*)attr + NLMSG_ALIGN(attr->nla_len))) {
if (attr->nla_type == DEVLINK_ATTR_NETDEV_NAME) {
char* port_name;
char netdev_name[IFNAMSIZ];
port_name = (char*)(attr + 1);
snprintf(netdev_name, sizeof(netdev_name), "%s%d", netdev_prefix,
netdev_index);
netlink_device_change(&nlmsg2, rtsock, port_name, true, 0, 0, 0,
netdev_name);
break;
}
}
offset += len;
netdev_index++;
}
error:
close(rtsock);
close(sock);
}

#define DEV_IPV4 "172.20.20.%d"
#define DEV_IPV6 "fe80::%02x"
#define DEV_MAC 0x00aaaaaaaaaa

static void netdevsim_add(unsigned int addr, unsigned int port_count) {
write_file("/sys/bus/netdevsim/del_device", "%u", addr);
if (write_file("/sys/bus/netdevsim/new_device", "%u %u", addr, port_count)) {
char buf[32];
snprintf(buf, sizeof(buf), "netdevsim%d", addr);
initialize_devlink_ports("netdevsim", buf, "netdevsim");
}
}

#define WG_GENL_NAME "wireguard"
enum wg_cmd {
WG_CMD_GET_DEVICE,
WG_CMD_SET_DEVICE,
};
enum wgdevice_attribute {
WGDEVICE_A_UNSPEC,
WGDEVICE_A_IFINDEX,
WGDEVICE_A_IFNAME,
WGDEVICE_A_PRIVATE_KEY,
WGDEVICE_A_PUBLIC_KEY,
WGDEVICE_A_FLAGS,
WGDEVICE_A_LISTEN_PORT,
WGDEVICE_A_FWMARK,
WGDEVICE_A_PEERS,
};
enum wgpeer_attribute {
WGPEER_A_UNSPEC,
WGPEER_A_PUBLIC_KEY,
WGPEER_A_PRESHARED_KEY,
WGPEER_A_FLAGS,
WGPEER_A_ENDPOINT,
WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL,
WGPEER_A_LAST_HANDSHAKE_TIME,
WGPEER_A_RX_BYTES,
WGPEER_A_TX_BYTES,
WGPEER_A_ALLOWEDIPS,
WGPEER_A_PROTOCOL_VERSION,
};
enum wgallowedip_attribute {
WGALLOWEDIP_A_UNSPEC,
WGALLOWEDIP_A_FAMILY,
WGALLOWEDIP_A_IPADDR,
WGALLOWEDIP_A_CIDR_MASK,
};

static void netlink_wireguard_setup(void) {
const char ifname_a[] = "wg0";
const char ifname_b[] = "wg1";
const char ifname_c[] = "wg2";
const char private_a[] =
"\xa0\x5c\xa8\x4f\x6c\x9c\x8e\x38\x53\xe2\xfd\x7a\x70\xae\x0f\xb2\x0f\xa1"
"\x52\x60\x0c\xb0\x08\x45\x17\x4f\x08\x07\x6f\x8d\x78\x43";
const char private_b[] =
"\xb0\x80\x73\xe8\xd4\x4e\x91\xe3\xda\x92\x2c\x22\x43\x82\x44\xbb\x88\x5c"
"\x69\xe2\x69\xc8\xe9\xd8\x35\xb1\x14\x29\x3a\x4d\xdc\x6e";
const char private_c[] =
"\xa0\xcb\x87\x9a\x47\xf5\xbc\x64\x4c\x0e\x69\x3f\xa6\xd0\x31\xc7\x4a\x15"
"\x53\xb6\xe9\x01\xb9\xff\x2f\x51\x8c\x78\x04\x2f\xb5\x42";
const char public_a[] =
"\x97\x5c\x9d\x81\xc9\x83\xc8\x20\x9e\xe7\x81\x25\x4b\x89\x9f\x8e\xd9\x25"
"\xae\x9f\x09\x23\xc2\x3c\x62\xf5\x3c\x57\xcd\xbf\x69\x1c";
const char public_b[] =
"\xd1\x73\x28\x99\xf6\x11\xcd\x89\x94\x03\x4d\x7f\x41\x3d\xc9\x57\x63\x0e"
"\x54\x93\xc2\x85\xac\xa4\x00\x65\xcb\x63\x11\xbe\x69\x6b";
const char public_c[] =
"\xf4\x4d\xa3\x67\xa8\x8e\xe6\x56\x4f\x02\x02\x11\x45\x67\x27\x08\x2f\x5c"
"\xeb\xee\x8b\x1b\xf5\xeb\x73\x37\x34\x1b\x45\x9b\x39\x22";
const uint16_t listen_a = 20001;
const uint16_t listen_b = 20002;
const uint16_t listen_c = 20003;
const uint16_t af_inet = AF_INET;
const uint16_t af_inet6 = AF_INET6;
const struct sockaddr_in endpoint_b_v4 = {
.sin_family = AF_INET,
.sin_port = htons(listen_b),
.sin_addr = {htonl(INADDR_LOOPBACK)}};
const struct sockaddr_in endpoint_c_v4 = {
.sin_family = AF_INET,
.sin_port = htons(listen_c),
.sin_addr = {htonl(INADDR_LOOPBACK)}};
struct sockaddr_in6 endpoint_a_v6 = {.sin6_family = AF_INET6,
.sin6_port = htons(listen_a)};
endpoint_a_v6.sin6_addr = in6addr_loopback;
struct sockaddr_in6 endpoint_c_v6 = {.sin6_family = AF_INET6,
.sin6_port = htons(listen_c)};
endpoint_c_v6.sin6_addr = in6addr_loopback;
const struct in_addr first_half_v4 = {0};
const struct in_addr second_half_v4 = {(uint32_t)htonl(128 << 24)};
const struct in6_addr first_half_v6 = {{{0}}};
const struct in6_addr second_half_v6 = {{{0x80}}};
const uint8_t half_cidr = 1;
const uint16_t persistent_keepalives[] = {1, 3, 7, 9, 14, 19};
struct genlmsghdr genlhdr = {.cmd = WG_CMD_SET_DEVICE, .version = 1};
int sock;
int id, err;
sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_GENERIC);
if (sock == -1) {
return;
}
id = netlink_query_family_id(&nlmsg, sock, WG_GENL_NAME, true);
if (id == -1)
goto error;
netlink_init(&nlmsg, id, 0, &genlhdr, sizeof(genlhdr));
netlink_attr(&nlmsg, WGDEVICE_A_IFNAME, ifname_a, strlen(ifname_a) + 1);
netlink_attr(&nlmsg, WGDEVICE_A_PRIVATE_KEY, private_a, 32);
netlink_attr(&nlmsg, WGDEVICE_A_LISTEN_PORT, &listen_a, 2);
netlink_nest(&nlmsg, NLA_F_NESTED | WGDEVICE_A_PEERS);
netlink_nest(&nlmsg, NLA_F_NESTED | 0);
netlink_attr(&nlmsg, WGPEER_A_PUBLIC_KEY, public_b, 32);
netlink_attr(&nlmsg, WGPEER_A_ENDPOINT, &endpoint_b_v4,
sizeof(endpoint_b_v4));
netlink_attr(&nlmsg, WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL,
&persistent_keepalives[0], 2);
netlink_nest(&nlmsg, NLA_F_NESTED | WGPEER_A_ALLOWEDIPS);
netlink_nest(&nlmsg, NLA_F_NESTED | 0);
netlink_attr(&nlmsg, WGALLOWEDIP_A_FAMILY, &af_inet, 2);
netlink_attr(&nlmsg, WGALLOWEDIP_A_IPADDR, &first_half_v4,
sizeof(first_half_v4));
netlink_attr(&nlmsg, WGALLOWEDIP_A_CIDR_MASK, &half_cidr, 1);
netlink_done(&nlmsg);
netlink_nest(&nlmsg, NLA_F_NESTED | 0);
netlink_attr(&nlmsg, WGALLOWEDIP_A_FAMILY, &af_inet6, 2);
netlink_attr(&nlmsg, WGALLOWEDIP_A_IPADDR, &first_half_v6,
sizeof(first_half_v6));
netlink_attr(&nlmsg, WGALLOWEDIP_A_CIDR_MASK, &half_cidr, 1);
netlink_done(&nlmsg);
netlink_done(&nlmsg);
netlink_done(&nlmsg);
netlink_nest(&nlmsg, NLA_F_NESTED | 0);
netlink_attr(&nlmsg, WGPEER_A_PUBLIC_KEY, public_c, 32);
netlink_attr(&nlmsg, WGPEER_A_ENDPOINT, &endpoint_c_v6,
sizeof(endpoint_c_v6));
netlink_attr(&nlmsg, WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL,
&persistent_keepalives[1], 2);
netlink_nest(&nlmsg, NLA_F_NESTED | WGPEER_A_ALLOWEDIPS);
netlink_nest(&nlmsg, NLA_F_NESTED | 0);
netlink_attr(&nlmsg, WGALLOWEDIP_A_FAMILY, &af_inet, 2);
netlink_attr(&nlmsg, WGALLOWEDIP_A_IPADDR, &second_half_v4,
sizeof(second_half_v4));
netlink_attr(&nlmsg, WGALLOWEDIP_A_CIDR_MASK, &half_cidr, 1);
netlink_done(&nlmsg);
netlink_nest(&nlmsg, NLA_F_NESTED | 0);
netlink_attr(&nlmsg, WGALLOWEDIP_A_FAMILY, &af_inet6, 2);
netlink_attr(&nlmsg, WGALLOWEDIP_A_IPADDR, &second_half_v6,
sizeof(second_half_v6));
netlink_attr(&nlmsg, WGALLOWEDIP_A_CIDR_MASK, &half_cidr, 1);
netlink_done(&nlmsg);
netlink_done(&nlmsg);
netlink_done(&nlmsg);
netlink_done(&nlmsg);
err = netlink_send(&nlmsg, sock);
if (err < 0) {
}
netlink_init(&nlmsg, id, 0, &genlhdr, sizeof(genlhdr));
netlink_attr(&nlmsg, WGDEVICE_A_IFNAME, ifname_b, strlen(ifname_b) + 1);
netlink_attr(&nlmsg, WGDEVICE_A_PRIVATE_KEY, private_b, 32);
netlink_attr(&nlmsg, WGDEVICE_A_LISTEN_PORT, &listen_b, 2);
netlink_nest(&nlmsg, NLA_F_NESTED | WGDEVICE_A_PEERS);
netlink_nest(&nlmsg, NLA_F_NESTED | 0);
netlink_attr(&nlmsg, WGPEER_A_PUBLIC_KEY, public_a, 32);
netlink_attr(&nlmsg, WGPEER_A_ENDPOINT, &endpoint_a_v6,
sizeof(endpoint_a_v6));
netlink_attr(&nlmsg, WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL,
&persistent_keepalives[2], 2);
netlink_nest(&nlmsg, NLA_F_NESTED | WGPEER_A_ALLOWEDIPS);
netlink_nest(&nlmsg, NLA_F_NESTED | 0);
netlink_attr(&nlmsg, WGALLOWEDIP_A_FAMILY, &af_inet, 2);
netlink_attr(&nlmsg, WGALLOWEDIP_A_IPADDR, &first_half_v4,
sizeof(first_half_v4));
netlink_attr(&nlmsg, WGALLOWEDIP_A_CIDR_MASK, &half_cidr, 1);
netlink_done(&nlmsg);
netlink_nest(&nlmsg, NLA_F_NESTED | 0);
netlink_attr(&nlmsg, WGALLOWEDIP_A_FAMILY, &af_inet6, 2);
netlink_attr(&nlmsg, WGALLOWEDIP_A_IPADDR, &first_half_v6,
sizeof(first_half_v6));
netlink_attr(&nlmsg, WGALLOWEDIP_A_CIDR_MASK, &half_cidr, 1);
netlink_done(&nlmsg);
netlink_done(&nlmsg);
netlink_done(&nlmsg);
netlink_nest(&nlmsg, NLA_F_NESTED | 0);
netlink_attr(&nlmsg, WGPEER_A_PUBLIC_KEY, public_c, 32);
netlink_attr(&nlmsg, WGPEER_A_ENDPOINT, &endpoint_c_v4,
sizeof(endpoint_c_v4));
netlink_attr(&nlmsg, WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL,
&persistent_keepalives[3], 2);
netlink_nest(&nlmsg, NLA_F_NESTED | WGPEER_A_ALLOWEDIPS);
netlink_nest(&nlmsg, NLA_F_NESTED | 0);
netlink_attr(&nlmsg, WGALLOWEDIP_A_FAMILY, &af_inet, 2);
netlink_attr(&nlmsg, WGALLOWEDIP_A_IPADDR, &second_half_v4,
sizeof(second_half_v4));
netlink_attr(&nlmsg, WGALLOWEDIP_A_CIDR_MASK, &half_cidr, 1);
netlink_done(&nlmsg);
netlink_nest(&nlmsg, NLA_F_NESTED | 0);
netlink_attr(&nlmsg, WGALLOWEDIP_A_FAMILY, &af_inet6, 2);
netlink_attr(&nlmsg, WGALLOWEDIP_A_IPADDR, &second_half_v6,
sizeof(second_half_v6));
netlink_attr(&nlmsg, WGALLOWEDIP_A_CIDR_MASK, &half_cidr, 1);
netlink_done(&nlmsg);
netlink_done(&nlmsg);
netlink_done(&nlmsg);
netlink_done(&nlmsg);
err = netlink_send(&nlmsg, sock);
if (err < 0) {
}
netlink_init(&nlmsg, id, 0, &genlhdr, sizeof(genlhdr));
netlink_attr(&nlmsg, WGDEVICE_A_IFNAME, ifname_c, strlen(ifname_c) + 1);
netlink_attr(&nlmsg, WGDEVICE_A_PRIVATE_KEY, private_c, 32);
netlink_attr(&nlmsg, WGDEVICE_A_LISTEN_PORT, &listen_c, 2);
netlink_nest(&nlmsg, NLA_F_NESTED | WGDEVICE_A_PEERS);
netlink_nest(&nlmsg, NLA_F_NESTED | 0);
netlink_attr(&nlmsg, WGPEER_A_PUBLIC_KEY, public_a, 32);
netlink_attr(&nlmsg, WGPEER_A_ENDPOINT, &endpoint_a_v6,
sizeof(endpoint_a_v6));
netlink_attr(&nlmsg, WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL,
&persistent_keepalives[4], 2);
netlink_nest(&nlmsg, NLA_F_NESTED | WGPEER_A_ALLOWEDIPS);
netlink_nest(&nlmsg, NLA_F_NESTED | 0);
netlink_attr(&nlmsg, WGALLOWEDIP_A_FAMILY, &af_inet, 2);
netlink_attr(&nlmsg, WGALLOWEDIP_A_IPADDR, &first_half_v4,
sizeof(first_half_v4));
netlink_attr(&nlmsg, WGALLOWEDIP_A_CIDR_MASK, &half_cidr, 1);
netlink_done(&nlmsg);
netlink_nest(&nlmsg, NLA_F_NESTED | 0);
netlink_attr(&nlmsg, WGALLOWEDIP_A_FAMILY, &af_inet6, 2);
netlink_attr(&nlmsg, WGALLOWEDIP_A_IPADDR, &first_half_v6,
sizeof(first_half_v6));
netlink_attr(&nlmsg, WGALLOWEDIP_A_CIDR_MASK, &half_cidr, 1);
netlink_done(&nlmsg);
netlink_done(&nlmsg);
netlink_done(&nlmsg);
netlink_nest(&nlmsg, NLA_F_NESTED | 0);
netlink_attr(&nlmsg, WGPEER_A_PUBLIC_KEY, public_b, 32);
netlink_attr(&nlmsg, WGPEER_A_ENDPOINT, &endpoint_b_v4,
sizeof(endpoint_b_v4));
netlink_attr(&nlmsg, WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL,
&persistent_keepalives[5], 2);
netlink_nest(&nlmsg, NLA_F_NESTED | WGPEER_A_ALLOWEDIPS);
netlink_nest(&nlmsg, NLA_F_NESTED | 0);
netlink_attr(&nlmsg, WGALLOWEDIP_A_FAMILY, &af_inet, 2);
netlink_attr(&nlmsg, WGALLOWEDIP_A_IPADDR, &second_half_v4,
sizeof(second_half_v4));
netlink_attr(&nlmsg, WGALLOWEDIP_A_CIDR_MASK, &half_cidr, 1);
netlink_done(&nlmsg);
netlink_nest(&nlmsg, NLA_F_NESTED | 0);
netlink_attr(&nlmsg, WGALLOWEDIP_A_FAMILY, &af_inet6, 2);
netlink_attr(&nlmsg, WGALLOWEDIP_A_IPADDR, &second_half_v6,
sizeof(second_half_v6));
netlink_attr(&nlmsg, WGALLOWEDIP_A_CIDR_MASK, &half_cidr, 1);
netlink_done(&nlmsg);
netlink_done(&nlmsg);
netlink_done(&nlmsg);
netlink_done(&nlmsg);
err = netlink_send(&nlmsg, sock);
if (err < 0) {
}

error:
close(sock);
}

static void initialize_netdevices(void) {
char netdevsim[16];
sprintf(netdevsim, "netdevsim%d", (int)procid);
struct {
const char* type;
const char* dev;
} devtypes[] = {
{"ip6gretap", "ip6gretap0"}, {"bridge", "bridge0"}, {"vcan", "vcan0"},
{"bond", "bond0"}, {"team", "team0"}, {"dummy", "dummy0"},
{"nlmon", "nlmon0"}, {"caif", "caif0"}, {"batadv", "batadv0"},
{"vxcan", "vxcan1"}, {"veth", 0}, {"wireguard", "wg0"},
{"wireguard", "wg1"}, {"wireguard", "wg2"},
};
const char* devmasters[] = {"bridge", "bond", "team", "batadv"};
struct {
const char* name;
int macsize;
bool noipv6;
} devices[] = {
{"lo", ETH_ALEN},
{"sit0", 0},
{"bridge0", ETH_ALEN},
{"vcan0", 0, true},
{"tunl0", 0},
{"gre0", 0},
{"gretap0", ETH_ALEN},
{"ip_vti0", 0},
{"ip6_vti0", 0},
{"ip6tnl0", 0},
{"ip6gre0", 0},
{"ip6gretap0", ETH_ALEN},
{"erspan0", ETH_ALEN},
{"bond0", ETH_ALEN},
{"veth0", ETH_ALEN},
{"veth1", ETH_ALEN},
{"team0", ETH_ALEN},
{"veth0_to_bridge", ETH_ALEN},
{"veth1_to_bridge", ETH_ALEN},
{"veth0_to_bond", ETH_ALEN},
{"veth1_to_bond", ETH_ALEN},
{"veth0_to_team", ETH_ALEN},
{"veth1_to_team", ETH_ALEN},
{"veth0_to_hsr", ETH_ALEN},
{"veth1_to_hsr", ETH_ALEN},
{"hsr0", 0},
{"dummy0", ETH_ALEN},
{"nlmon0", 0},
{"vxcan0", 0, true},
{"vxcan1", 0, true},
{"caif0", ETH_ALEN},
{"batadv0", ETH_ALEN},
{netdevsim, ETH_ALEN},
{"xfrm0", ETH_ALEN},
{"veth0_virt_wifi", ETH_ALEN},
{"veth1_virt_wifi", ETH_ALEN},
{"virt_wifi0", ETH_ALEN},
{"veth0_vlan", ETH_ALEN},
{"veth1_vlan", ETH_ALEN},
{"vlan0", ETH_ALEN},
{"vlan1", ETH_ALEN},
{"macvlan0", ETH_ALEN},
{"macvlan1", ETH_ALEN},
{"ipvlan0", ETH_ALEN},
{"ipvlan1", ETH_ALEN},
{"veth0_macvtap", ETH_ALEN},
{"veth1_macvtap", ETH_ALEN},
{"macvtap0", ETH_ALEN},
{"macsec0", ETH_ALEN},
{"veth0_to_batadv", ETH_ALEN},
{"veth1_to_batadv", ETH_ALEN},
{"batadv_slave_0", ETH_ALEN},
{"batadv_slave_1", ETH_ALEN},
{"geneve0", ETH_ALEN},
{"geneve1", ETH_ALEN},
{"wg0", 0},
{"wg1", 0},
{"wg2", 0},
};
int sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (sock == -1)
exit(1);
unsigned i;
for (i = 0; i < sizeof(devtypes) / sizeof(devtypes[0]); i++)
netlink_add_device(&nlmsg, sock, devtypes[i].type, devtypes[i].dev);
for (i = 0; i < sizeof(devmasters) / (sizeof(devmasters[0])); i++) {
char master[32], slave0[32], veth0[32], slave1[32], veth1[32];
sprintf(slave0, "%s_slave_0", devmasters[i]);
sprintf(veth0, "veth0_to_%s", devmasters[i]);
netlink_add_veth(&nlmsg, sock, slave0, veth0);
sprintf(slave1, "%s_slave_1", devmasters[i]);
sprintf(veth1, "veth1_to_%s", devmasters[i]);
netlink_add_veth(&nlmsg, sock, slave1, veth1);
sprintf(master, "%s0", devmasters[i]);
netlink_device_change(&nlmsg, sock, slave0, false, master, 0, 0, NULL);
netlink_device_change(&nlmsg, sock, slave1, false, master, 0, 0, NULL);
}
netlink_add_xfrm(&nlmsg, sock, "xfrm0");
netlink_device_change(&nlmsg, sock, "bridge_slave_0", true, 0, 0, 0, NULL);
netlink_device_change(&nlmsg, sock, "bridge_slave_1", true, 0, 0, 0, NULL);
netlink_add_veth(&nlmsg, sock, "hsr_slave_0", "veth0_to_hsr");
netlink_add_veth(&nlmsg, sock, "hsr_slave_1", "veth1_to_hsr");
netlink_add_hsr(&nlmsg, sock, "hsr0", "hsr_slave_0", "hsr_slave_1");
netlink_device_change(&nlmsg, sock, "hsr_slave_0", true, 0, 0, 0, NULL);
netlink_device_change(&nlmsg, sock, "hsr_slave_1", true, 0, 0, 0, NULL);
netlink_add_veth(&nlmsg, sock, "veth0_virt_wifi", "veth1_virt_wifi");
netlink_add_linked(&nlmsg, sock, "virt_wifi", "virt_wifi0",
"veth1_virt_wifi");
netlink_add_veth(&nlmsg, sock, "veth0_vlan", "veth1_vlan");
netlink_add_vlan(&nlmsg, sock, "vlan0", "veth0_vlan", 0, htons(ETH_P_8021Q));
netlink_add_vlan(&nlmsg, sock, "vlan1", "veth0_vlan", 1, htons(ETH_P_8021AD));
netlink_add_macvlan(&nlmsg, sock, "macvlan0", "veth1_vlan");
netlink_add_macvlan(&nlmsg, sock, "macvlan1", "veth1_vlan");
netlink_add_ipvlan(&nlmsg, sock, "ipvlan0", "veth0_vlan", IPVLAN_MODE_L2, 0);
netlink_add_ipvlan(&nlmsg, sock, "ipvlan1", "veth0_vlan", IPVLAN_MODE_L3S,
IPVLAN_F_VEPA);
netlink_add_veth(&nlmsg, sock, "veth0_macvtap", "veth1_macvtap");
netlink_add_linked(&nlmsg, sock, "macvtap", "macvtap0", "veth0_macvtap");
netlink_add_linked(&nlmsg, sock, "macsec", "macsec0", "veth1_macvtap");
char addr[32];
sprintf(addr, DEV_IPV4, 14 + 10);
struct in_addr geneve_addr4;
if (inet_pton(AF_INET, addr, &geneve_addr4) <= 0)
exit(1);
struct in6_addr geneve_addr6;
if (inet_pton(AF_INET6, "fc00::01", &geneve_addr6) <= 0)
exit(1);
netlink_add_geneve(&nlmsg, sock, "geneve0", 0, &geneve_addr4, 0);
netlink_add_geneve(&nlmsg, sock, "geneve1", 1, 0, &geneve_addr6);
netdevsim_add((int)procid, 4);
netlink_wireguard_setup();
for (i = 0; i < sizeof(devices) / (sizeof(devices[0])); i++) {
char addr[32];
sprintf(addr, DEV_IPV4, i + 10);
netlink_add_addr4(&nlmsg, sock, devices[i].name, addr);
if (!devices[i].noipv6) {
sprintf(addr, DEV_IPV6, i + 10);
netlink_add_addr6(&nlmsg, sock, devices[i].name, addr);
}
uint64_t macaddr = DEV_MAC + ((i + 10ull) << 40);
netlink_device_change(&nlmsg, sock, devices[i].name, true, 0, &macaddr,
devices[i].macsize, NULL);
}
close(sock);
}
static void initialize_netdevices_init(void) {
int sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (sock == -1)
exit(1);
struct {
const char* type;
int macsize;
bool noipv6;
bool noup;
} devtypes[] = {
{"nr", 7, true},
{"rose", 5, true, true},
};
unsigned i;
for (i = 0; i < sizeof(devtypes) / sizeof(devtypes[0]); i++) {
char dev[32], addr[32];
sprintf(dev, "%s%d", devtypes[i].type, (int)procid);
sprintf(addr, "172.30.%d.%d", i, (int)procid + 1);
netlink_add_addr4(&nlmsg, sock, dev, addr);
if (!devtypes[i].noipv6) {
sprintf(addr, "fe88::%02x:%02x", i, (int)procid + 1);
netlink_add_addr6(&nlmsg, sock, dev, addr);
}
int macsize = devtypes[i].macsize;
uint64_t macaddr = 0xbbbbbb +
((unsigned long long)i << (8 * (macsize - 2))) +
(procid << (8 * (macsize - 1)));
netlink_device_change(&nlmsg, sock, dev, !devtypes[i].noup, 0, &macaddr,
macsize, NULL);
}
close(sock);
}

static void setup_common() {
if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 0)) {
}
}

static void setup_binderfs() {
if (mkdir("/dev/binderfs", 0777)) {
}
if (mount("binder", "/dev/binderfs", "binder", 0, NULL)) {
}
if (symlink("/dev/binderfs", "./binderfs")) {
}
}

static void loop();

static void sandbox_common() {
prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
setsid();
struct rlimit rlim;
rlim.rlim_cur = rlim.rlim_max = (200 << 20);
setrlimit(RLIMIT_AS, &rlim);
rlim.rlim_cur = rlim.rlim_max = 32 << 20;
setrlimit(RLIMIT_MEMLOCK, &rlim);
rlim.rlim_cur = rlim.rlim_max = 136 << 20;
setrlimit(RLIMIT_FSIZE, &rlim);
rlim.rlim_cur = rlim.rlim_max = 1 << 20;
setrlimit(RLIMIT_STACK, &rlim);
rlim.rlim_cur = rlim.rlim_max = 128 << 20;
setrlimit(RLIMIT_CORE, &rlim);
rlim.rlim_cur = rlim.rlim_max = 256;
setrlimit(RLIMIT_NOFILE, &rlim);
if (unshare(CLONE_NEWNS)) {
}
if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL)) {
}
if (unshare(CLONE_NEWIPC)) {
}
if (unshare(0x02000000)) {
}
if (unshare(CLONE_NEWUTS)) {
}
if (unshare(CLONE_SYSVSEM)) {
}
typedef struct {
const char* name;
const char* value;
} sysctl_t;
static const sysctl_t sysctls[] = {
{"/proc/sys/kernel/shmmax", "16777216"},
{"/proc/sys/kernel/shmall", "536870912"},
{"/proc/sys/kernel/shmmni", "1024"},
{"/proc/sys/kernel/msgmax", "8192"},
{"/proc/sys/kernel/msgmni", "1024"},
{"/proc/sys/kernel/msgmnb", "1024"},
{"/proc/sys/kernel/sem", "1024 1048576 500 1024"},
};
unsigned i;
for (i = 0; i < sizeof(sysctls) / sizeof(sysctls[0]); i++)
write_file(sysctls[i].name, sysctls[i].value);
}

static int wait_for_loop(int pid) {
if (pid < 0)
exit(1);
int status = 0;
while (waitpid(-1, &status, __WALL) != pid) {
}
return WEXITSTATUS(status);
}

static void drop_caps(void) {
struct __user_cap_header_struct cap_hdr = {};
struct __user_cap_data_struct cap_data[2] = {};
cap_hdr.version = _LINUX_CAPABILITY_VERSION_3;
cap_hdr.pid = getpid();
if (syscall(SYS_capget, &cap_hdr, &cap_data))
exit(1);
const int drop = (1 << CAP_SYS_PTRACE) | (1 << CAP_SYS_NICE);
cap_data[0].effective &= ~drop;
cap_data[0].permitted &= ~drop;
cap_data[0].inheritable &= ~drop;
if (syscall(SYS_capset, &cap_hdr, &cap_data))
exit(1);
}

static int do_sandbox_none(void) {
if (unshare(CLONE_NEWPID)) {
}
int pid = fork();
if (pid != 0)
return wait_for_loop(pid);
setup_common();
sandbox_common();
drop_caps();
initialize_netdevices_init();
if (unshare(CLONE_NEWNET)) {
}
write_file("/proc/sys/net/ipv4/ping_group_range", "0 65535");
initialize_tun();
initialize_netdevices();
setup_binderfs();
loop();
exit(1);
}

uint64_t r[2] = {0xffffffffffffffff, 0xffffffffffffffff};

void loop(void) {
intptr_t res = 0;
res = syscall(__NR_socket, /*domain=*/0x10ul, /*type=*/3ul, /*proto=*/0);
if (res != -1)
r[0] = res;
*(uint64_t*)0x20000040 = 0x20000080;
memcpy((void*)0x20000080,
"\x39\x00\x00\x00\x13\x00\x0b\x46\x00\xbb\x65\xe1\xc3\xe4\xff\xff\xf9"
"\xff\xff\x7f\x37\x00\x00\x00\x56\x00\x00\x02\x25\x00\x00\x00\x19\x00"
"\x0a\x00\x10\x00\x00\x00\x07\xfd\x17\xe5\xff\xff\x08\x00\x04\x00\x00"
"\x00\x00\x00\x00\x00\x0a",
57);
*(uint64_t*)0x20000048 = 0x39;
syscall(__NR_writev, /*fd=*/r[0], /*vec=*/0x20000040ul, /*vlen=*/1ul);
res = syscall(__NR_socket, /*domain=*/0x10ul, /*type=*/3ul, /*proto=*/0);
if (res != -1)
r[1] = res;
*(uint64_t*)0x20000040 = 0x20000080;
memcpy((void*)0x20000080,
"\x39\x00\x00\x00\x13\x00\x0b\x46\x00\xbb\x65\xe1\xc3\xe4\xff\xff\x01"
"\x00\x00\x00\x36\x00\x00\x00\x56\x00\x00\x02\x25\x00\x00\x00\x19\x00"
"\x0a\x00\x10\x00\x00\x00\x07\xfd\x17\xe5\xff\xff\x08\x00\x04\x00\x00"
"\x00\x00\x00\x00\x00\x0a",
57);
*(uint64_t*)0x20000048 = 0x39;
syscall(__NR_writev, /*fd=*/r[1], /*vec=*/0x20000040ul, /*vlen=*/1ul);
}
int main(void) {
syscall(__NR_mmap, /*addr=*/0x1ffff000ul, /*len=*/0x1000ul, /*prot=*/0ul,
/*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul);
syscall(__NR_mmap, /*addr=*/0x20000000ul, /*len=*/0x1000000ul, /*prot=*/7ul,
/*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul);
syscall(__NR_mmap, /*addr=*/0x21000000ul, /*len=*/0x1000ul, /*prot=*/0ul,
/*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul);
do_sandbox_none();
return 0;
}


and also https://gist.github.com/xrivendell7/dea2d84fe5efdb17eedcdb3e17297ffe

I hope it helps.
Best regards
xingwei Lee