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/* SPDX-License-Identifier: GPL-2.0 */
// Copyright (c) 2018 Covalent IO, Inc. http://covalent.io
#include <stddef.h>
#include <stdbool.h>
#include <string.h>
#include <linux/bpf.h>
#include <linux/if_ether.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/pkt_cls.h>
#include <linux/tcp.h>
#include <sys/socket.h>
#include "bpf_helpers.h"
#include "bpf_endian.h"
int _version SEC("version") = 1;
char _license[] SEC("license") = "GPL";
/* Fill 'tuple' with L3 info, and attempt to find L4. On fail, return NULL. */
static struct bpf_sock_tuple *get_tuple(void *data, __u64 nh_off,
void *data_end, __u16 eth_proto,
bool *ipv4)
{
struct bpf_sock_tuple *result;
__u8 proto = 0;
__u64 ihl_len;
if (eth_proto == bpf_htons(ETH_P_IP)) {
struct iphdr *iph = (struct iphdr *)(data + nh_off);
if (iph + 1 > data_end)
return NULL;
ihl_len = iph->ihl * 4;
proto = iph->protocol;
*ipv4 = true;
result = (struct bpf_sock_tuple *)&iph->saddr;
} else if (eth_proto == bpf_htons(ETH_P_IPV6)) {
struct ipv6hdr *ip6h = (struct ipv6hdr *)(data + nh_off);
if (ip6h + 1 > data_end)
return NULL;
ihl_len = sizeof(*ip6h);
proto = ip6h->nexthdr;
*ipv4 = true;
result = (struct bpf_sock_tuple *)&ip6h->saddr;
}
if (data + nh_off + ihl_len > data_end || proto != IPPROTO_TCP)
return NULL;
return result;
}
SEC("sk_lookup_success")
int bpf_sk_lookup_test0(struct __sk_buff *skb)
{
void *data_end = (void *)(long)skb->data_end;
void *data = (void *)(long)skb->data;
struct ethhdr *eth = (struct ethhdr *)(data);
struct bpf_sock_tuple *tuple;
struct bpf_sock *sk;
size_t tuple_len;
bool ipv4;
if (eth + 1 > data_end)
return TC_ACT_SHOT;
tuple = get_tuple(data, sizeof(*eth), data_end, eth->h_proto, &ipv4);
if (!tuple || tuple + sizeof *tuple > data_end)
return TC_ACT_SHOT;
tuple_len = ipv4 ? sizeof(tuple->ipv4) : sizeof(tuple->ipv6);
sk = bpf_sk_lookup_tcp(skb, tuple, tuple_len, 0, 0);
if (sk)
bpf_sk_release(sk);
return sk ? TC_ACT_OK : TC_ACT_UNSPEC;
}
SEC("sk_lookup_success_simple")
int bpf_sk_lookup_test1(struct __sk_buff *skb)
{
struct bpf_sock_tuple tuple = {};
struct bpf_sock *sk;
sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
if (sk)
bpf_sk_release(sk);
return 0;
}
SEC("fail_use_after_free")
int bpf_sk_lookup_uaf(struct __sk_buff *skb)
{
struct bpf_sock_tuple tuple = {};
struct bpf_sock *sk;
__u32 family = 0;
sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
if (sk) {
bpf_sk_release(sk);
family = sk->family;
}
return family;
}
SEC("fail_modify_sk_pointer")
int bpf_sk_lookup_modptr(struct __sk_buff *skb)
{
struct bpf_sock_tuple tuple = {};
struct bpf_sock *sk;
__u32 family;
sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
if (sk) {
sk += 1;
bpf_sk_release(sk);
}
return 0;
}
SEC("fail_modify_sk_or_null_pointer")
int bpf_sk_lookup_modptr_or_null(struct __sk_buff *skb)
{
struct bpf_sock_tuple tuple = {};
struct bpf_sock *sk;
__u32 family;
sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
sk += 1;
if (sk)
bpf_sk_release(sk);
return 0;
}
SEC("fail_no_release")
int bpf_sk_lookup_test2(struct __sk_buff *skb)
{
struct bpf_sock_tuple tuple = {};
bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
return 0;
}
SEC("fail_release_twice")
int bpf_sk_lookup_test3(struct __sk_buff *skb)
{
struct bpf_sock_tuple tuple = {};
struct bpf_sock *sk;
sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
bpf_sk_release(sk);
bpf_sk_release(sk);
return 0;
}
SEC("fail_release_unchecked")
int bpf_sk_lookup_test4(struct __sk_buff *skb)
{
struct bpf_sock_tuple tuple = {};
struct bpf_sock *sk;
sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
bpf_sk_release(sk);
return 0;
}
void lookup_no_release(struct __sk_buff *skb)
{
struct bpf_sock_tuple tuple = {};
bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), 0, 0);
}
SEC("fail_no_release_subcall")
int bpf_sk_lookup_test5(struct __sk_buff *skb)
{
lookup_no_release(skb);
return 0;
}
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