| From bea500f6f6296234deac0ed6d6af8b1a1c006484 Mon Sep 17 00:00:00 2001 |
| From: Andrzej Ostruszka <amo@semihalf.com> |
| Date: Thu, 4 Nov 2021 09:53:08 +0000 |
| Subject: [PATCH 2/3] Correct length check in BPF ARP filter |
| |
| The packet length should be compared against both Ethernet header |
| (struct ether_header) and ARP packet (struct ether_arp). |
| --- |
| src/bpf.c | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| diff --git a/src/bpf.c b/src/bpf.c |
| index 0e9277d0..ea08c846 100644 |
| --- a/src/bpf.c |
| +++ b/src/bpf.c |
| @@ -395,7 +395,8 @@ bpf_cmp_hwaddr(struct bpf_insn *bpf, size_t bpf_len, size_t off, |
| static const struct bpf_insn bpf_arp_ether [] = { |
| /* Ensure packet is at least correct size. */ |
| BPF_STMT(BPF_LD + BPF_W + BPF_LEN, 0), |
| - BPF_JUMP(BPF_JMP + BPF_JGE + BPF_K, sizeof(struct ether_arp), 1, 0), |
| + BPF_JUMP(BPF_JMP + BPF_JGE + BPF_K, |
| + sizeof(struct ether_header) + sizeof(struct ether_arp), 1, 0), |
| BPF_STMT(BPF_RET + BPF_K, 0), |
| |
| /* Check this is an ARP packet. */ |
| -- |
| 2.34.0.rc0.344.g81b53c2807-goog |
| |
