selftests/bpf: add a test for overlapping packet range checks
add simple C test case for llvm and verifier range check fix from
commit b1977682a385 ("bpf: improve verifier packet range checks")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/tools/testing/selftests/bpf/test_pkt_access.c b/tools/testing/selftests/bpf/test_pkt_access.c
new file mode 100644
index 0000000..fd1e083
--- /dev/null
+++ b/tools/testing/selftests/bpf/test_pkt_access.c
@@ -0,0 +1,64 @@
+/* Copyright (c) 2017 Facebook
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#include <stddef.h>
+#include <linux/bpf.h>
+#include <linux/if_ether.h>
+#include <linux/if_packet.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include <linux/in.h>
+#include <linux/tcp.h>
+#include <linux/pkt_cls.h>
+#include "bpf_helpers.h"
+
+#define _htons __builtin_bswap16
+#define barrier() __asm__ __volatile__("": : :"memory")
+int _version SEC("version") = 1;
+
+SEC("test1")
+int process(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 tcphdr *tcp = NULL;
+ __u8 proto = 255;
+ __u64 ihl_len;
+
+ if (eth + 1 > data_end)
+ return TC_ACT_SHOT;
+
+ if (eth->h_proto == _htons(ETH_P_IP)) {
+ struct iphdr *iph = (struct iphdr *)(eth + 1);
+
+ if (iph + 1 > data_end)
+ return TC_ACT_SHOT;
+ ihl_len = iph->ihl * 4;
+ proto = iph->protocol;
+ tcp = (struct tcphdr *)((void *)(iph) + ihl_len);
+ } else if (eth->h_proto == _htons(ETH_P_IPV6)) {
+ struct ipv6hdr *ip6h = (struct ipv6hdr *)(eth + 1);
+
+ if (ip6h + 1 > data_end)
+ return TC_ACT_SHOT;
+ ihl_len = sizeof(*ip6h);
+ proto = ip6h->nexthdr;
+ tcp = (struct tcphdr *)((void *)(ip6h) + ihl_len);
+ }
+
+ if (tcp) {
+ if (((void *)(tcp) + 20) > data_end || proto != 6)
+ return TC_ACT_SHOT;
+ barrier(); /* to force ordering of checks */
+ if (((void *)(tcp) + 18) > data_end)
+ return TC_ACT_SHOT;
+ if (tcp->urg_ptr == 123)
+ return TC_ACT_OK;
+ }
+
+ return TC_ACT_UNSPEC;
+}