tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/* SPDX-License-Identifier: GPL-2.0 */
2// Copyright (c) 2018 Covalent IO, Inc. http://covalent.io
3
4#include <stddef.h>
5#include <stdbool.h>
6#include <string.h>
7#include <linux/bpf.h>
8#include <linux/if_ether.h>
9#include <linux/in.h>
10#include <linux/ip.h>
11#include <linux/ipv6.h>
12#include <linux/pkt_cls.h>
13#include <linux/tcp.h>
14#include <sys/socket.h>
15#include <bpf/bpf_helpers.h>
16#include <bpf/bpf_endian.h>
17
18int _version SEC("version") = 1;
19char _license[] SEC("license") = "GPL";
20
21/* Fill 'tuple' with L3 info, and attempt to find L4. On fail, return NULL. */
22static struct bpf_sock_tuple *get_tuple(void *data, __u64 nh_off,
23 void *data_end, __u16 eth_proto,
24 bool *ipv4)
25{
26 struct bpf_sock_tuple *result;
27 __u8 proto = 0;
28 __u64 ihl_len;
29
30 if (eth_proto == bpf_htons(ETH_P_IP)) {
31 struct iphdr *iph = (struct iphdr *)(data + nh_off);
32
33 if (iph + 1 > data_end)
34 return NULL;
35 ihl_len = iph->ihl * 4;
36 proto = iph->protocol;
37 *ipv4 = true;
38 result = (struct bpf_sock_tuple *)&iph->saddr;
39 } else if (eth_proto == bpf_htons(ETH_P_IPV6)) {
40 struct ipv6hdr *ip6h = (struct ipv6hdr *)(data + nh_off);
41
42 if (ip6h + 1 > data_end)
43 return NULL;
44 ihl_len = sizeof(*ip6h);
45 proto = ip6h->nexthdr;
46 *ipv4 = true;
47 result = (struct bpf_sock_tuple *)&ip6h->saddr;
48 }
49
50 if (data + nh_off + ihl_len > data_end || proto != IPPROTO_TCP)
51 return NULL;
52
53 return result;
54}
55
56SEC("classifier/sk_lookup_success")
57int bpf_sk_lookup_test0(struct __sk_buff *skb)
58{
59 void *data_end = (void *)(long)skb->data_end;
60 void *data = (void *)(long)skb->data;
61 struct ethhdr *eth = (struct ethhdr *)(data);
62 struct bpf_sock_tuple *tuple;
63 struct bpf_sock *sk;
64 size_t tuple_len;
65 bool ipv4;
66
67 if (eth + 1 > data_end)
68 return TC_ACT_SHOT;
69
70 tuple = get_tuple(data, sizeof(*eth), data_end, eth->h_proto, &ipv4);
71 if (!tuple || tuple + sizeof *tuple > data_end)
72 return TC_ACT_SHOT;
73
74 tuple_len = ipv4 ? sizeof(tuple->ipv4) : sizeof(tuple->ipv6);
75 sk = bpf_sk_lookup_tcp(skb, tuple, tuple_len, BPF_F_CURRENT_NETNS, 0);
76 bpf_printk("sk=%d\n", sk ? 1 : 0);
77 if (sk)
78 bpf_sk_release(sk);
79 return sk ? TC_ACT_OK : TC_ACT_UNSPEC;
80}
81
82SEC("classifier/sk_lookup_success_simple")
83int bpf_sk_lookup_test1(struct __sk_buff *skb)
84{
85 struct bpf_sock_tuple tuple = {};
86 struct bpf_sock *sk;
87
88 sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), BPF_F_CURRENT_NETNS, 0);
89 if (sk)
90 bpf_sk_release(sk);
91 return 0;
92}
93
94SEC("classifier/fail_use_after_free")
95int bpf_sk_lookup_uaf(struct __sk_buff *skb)
96{
97 struct bpf_sock_tuple tuple = {};
98 struct bpf_sock *sk;
99 __u32 family = 0;
100
101 sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), BPF_F_CURRENT_NETNS, 0);
102 if (sk) {
103 bpf_sk_release(sk);
104 family = sk->family;
105 }
106 return family;
107}
108
109SEC("classifier/fail_modify_sk_pointer")
110int bpf_sk_lookup_modptr(struct __sk_buff *skb)
111{
112 struct bpf_sock_tuple tuple = {};
113 struct bpf_sock *sk;
114 __u32 family;
115
116 sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), BPF_F_CURRENT_NETNS, 0);
117 if (sk) {
118 sk += 1;
119 bpf_sk_release(sk);
120 }
121 return 0;
122}
123
124SEC("classifier/fail_modify_sk_or_null_pointer")
125int bpf_sk_lookup_modptr_or_null(struct __sk_buff *skb)
126{
127 struct bpf_sock_tuple tuple = {};
128 struct bpf_sock *sk;
129 __u32 family;
130
131 sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), BPF_F_CURRENT_NETNS, 0);
132 sk += 1;
133 if (sk)
134 bpf_sk_release(sk);
135 return 0;
136}
137
138SEC("classifier/fail_no_release")
139int bpf_sk_lookup_test2(struct __sk_buff *skb)
140{
141 struct bpf_sock_tuple tuple = {};
142
143 bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), BPF_F_CURRENT_NETNS, 0);
144 return 0;
145}
146
147SEC("classifier/fail_release_twice")
148int bpf_sk_lookup_test3(struct __sk_buff *skb)
149{
150 struct bpf_sock_tuple tuple = {};
151 struct bpf_sock *sk;
152
153 sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), BPF_F_CURRENT_NETNS, 0);
154 bpf_sk_release(sk);
155 bpf_sk_release(sk);
156 return 0;
157}
158
159SEC("classifier/fail_release_unchecked")
160int bpf_sk_lookup_test4(struct __sk_buff *skb)
161{
162 struct bpf_sock_tuple tuple = {};
163 struct bpf_sock *sk;
164
165 sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), BPF_F_CURRENT_NETNS, 0);
166 bpf_sk_release(sk);
167 return 0;
168}
169
170void lookup_no_release(struct __sk_buff *skb)
171{
172 struct bpf_sock_tuple tuple = {};
173 bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), BPF_F_CURRENT_NETNS, 0);
174}
175
176SEC("classifier/fail_no_release_subcall")
177int bpf_sk_lookup_test5(struct __sk_buff *skb)
178{
179 lookup_no_release(skb);
180 return 0;
181}