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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 | /* 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/bpf_helpers.h> #include <bpf/bpf_endian.h> 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; __u64 ihl_len = 0; __u8 proto = 0; 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("?tc") int sk_lookup_success(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, BPF_F_CURRENT_NETNS, 0); bpf_printk("sk=%d\n", sk ? 1 : 0); if (sk) bpf_sk_release(sk); return sk ? TC_ACT_OK : TC_ACT_UNSPEC; } SEC("?tc") int sk_lookup_success_simple(struct __sk_buff *skb) { struct bpf_sock_tuple tuple = {}; struct bpf_sock *sk; sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), BPF_F_CURRENT_NETNS, 0); if (sk) bpf_sk_release(sk); return 0; } SEC("?tc") int err_use_after_free(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), BPF_F_CURRENT_NETNS, 0); if (sk) { bpf_sk_release(sk); family = sk->family; } return family; } SEC("?tc") int err_modify_sk_pointer(struct __sk_buff *skb) { struct bpf_sock_tuple tuple = {}; struct bpf_sock *sk; sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), BPF_F_CURRENT_NETNS, 0); if (sk) { sk += 1; bpf_sk_release(sk); } return 0; } SEC("?tc") int err_modify_sk_or_null_pointer(struct __sk_buff *skb) { struct bpf_sock_tuple tuple = {}; struct bpf_sock *sk; sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), BPF_F_CURRENT_NETNS, 0); sk += 1; if (sk) bpf_sk_release(sk); return 0; } SEC("?tc") int err_no_release(struct __sk_buff *skb) { struct bpf_sock_tuple tuple = {}; bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), BPF_F_CURRENT_NETNS, 0); return 0; } SEC("?tc") int err_release_twice(struct __sk_buff *skb) { struct bpf_sock_tuple tuple = {}; struct bpf_sock *sk; sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), BPF_F_CURRENT_NETNS, 0); bpf_sk_release(sk); bpf_sk_release(sk); return 0; } SEC("?tc") int err_release_unchecked(struct __sk_buff *skb) { struct bpf_sock_tuple tuple = {}; struct bpf_sock *sk; sk = bpf_sk_lookup_tcp(skb, &tuple, sizeof(tuple), BPF_F_CURRENT_NETNS, 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), BPF_F_CURRENT_NETNS, 0); } SEC("?tc") int err_no_release_subcall(struct __sk_buff *skb) { lookup_no_release(skb); return 0; } |