From 7fc38225363dd8f19e667ad7c77b63bc4a5c065d Mon Sep 17 00:00:00 2001 From: Alin Nastac Date: Wed, 13 Feb 2019 09:14:53 +0100 Subject: netfilter: reject: skip csum verification for protocols that don't support it Some protocols have other means to verify the payload integrity (AH, ESP, SCTP) while others are incompatible with nf_ip(6)_checksum implementation because checksum is either optional or might be partial (UDPLITE, DCCP, GRE). Because nf_ip(6)_checksum was used to validate the packets, ip(6)tables REJECT rules were not capable to generate ICMP(v6) errors for the protocols mentioned above. This commit also fixes the incorrect pseudo-header protocol used for IPv4 packets that carry other transport protocols than TCP or UDP (pseudo-header used protocol 0 iso the proper value). Signed-off-by: Alin Nastac Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/nf_reject_ipv4.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/netfilter/nf_reject_ipv4.c b/net/ipv4/netfilter/nf_reject_ipv4.c index aa8304c618b8..7dc3c324b911 100644 --- a/net/ipv4/netfilter/nf_reject_ipv4.c +++ b/net/ipv4/netfilter/nf_reject_ipv4.c @@ -173,21 +173,16 @@ EXPORT_SYMBOL_GPL(nf_send_reset); void nf_send_unreach(struct sk_buff *skb_in, int code, int hook) { struct iphdr *iph = ip_hdr(skb_in); - u8 proto; + u8 proto = iph->protocol; if (iph->frag_off & htons(IP_OFFSET)) return; - if (skb_csum_unnecessary(skb_in)) { + if (skb_csum_unnecessary(skb_in) || !nf_reject_verify_csum(proto)) { icmp_send(skb_in, ICMP_DEST_UNREACH, code, 0); return; } - if (iph->protocol == IPPROTO_TCP || iph->protocol == IPPROTO_UDP) - proto = iph->protocol; - else - proto = 0; - if (nf_ip_checksum(skb_in, hook, ip_hdrlen(skb_in), proto) == 0) icmp_send(skb_in, ICMP_DEST_UNREACH, code, 0); } -- cgit v1.2.3-59-g8ed1b