diff options
| author | Kevin Mitchell <kevmitch@arista.com> | 2022-04-30 06:40:27 +0300 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2022-05-13 19:56:28 +0300 |
| commit | 4f9bd53084d18c2f9f1ec68fa56587b99a2cef00 (patch) | |
| tree | 287511e3eef2de3ab09b254d707966341b92b3d3 /net/ipv4 | |
| parent | 3412e16418286bdc12561827cbd22f94cb8af5e1 (diff) | |
| download | linux-4f9bd53084d18c2f9f1ec68fa56587b99a2cef00.tar.xz | |
netfilter: conntrack: skip verification of zero UDP checksum
The checksum is optional for UDP packets. However nf_reject would
previously require a valid checksum to elicit a response such as
ICMP_DEST_UNREACH.
Add some logic to nf_reject_verify_csum to determine if a UDP packet has
a zero checksum and should therefore not be verified.
Signed-off-by: Kevin Mitchell <kevmitch@arista.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/netfilter/nf_reject_ipv4.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/net/ipv4/netfilter/nf_reject_ipv4.c b/net/ipv4/netfilter/nf_reject_ipv4.c index 4eed5afca392..918c61fda0f3 100644 --- a/net/ipv4/netfilter/nf_reject_ipv4.c +++ b/net/ipv4/netfilter/nf_reject_ipv4.c @@ -80,6 +80,7 @@ struct sk_buff *nf_reject_skb_v4_unreach(struct net *net, struct iphdr *niph; struct icmphdr *icmph; unsigned int len; + int dataoff; __wsum csum; u8 proto; @@ -99,10 +100,11 @@ struct sk_buff *nf_reject_skb_v4_unreach(struct net *net, if (pskb_trim_rcsum(oldskb, ntohs(ip_hdr(oldskb)->tot_len))) return NULL; + dataoff = ip_hdrlen(oldskb); proto = ip_hdr(oldskb)->protocol; if (!skb_csum_unnecessary(oldskb) && - nf_reject_verify_csum(proto) && + nf_reject_verify_csum(oldskb, dataoff, proto) && nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), proto)) return NULL; @@ -311,6 +313,7 @@ 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); + int dataoff = ip_hdrlen(skb_in); u8 proto = iph->protocol; if (iph->frag_off & htons(IP_OFFSET)) @@ -320,12 +323,13 @@ void nf_send_unreach(struct sk_buff *skb_in, int code, int hook) nf_reject_fill_skb_dst(skb_in) < 0) return; - if (skb_csum_unnecessary(skb_in) || !nf_reject_verify_csum(proto)) { + if (skb_csum_unnecessary(skb_in) || + !nf_reject_verify_csum(skb_in, dataoff, proto)) { icmp_send(skb_in, ICMP_DEST_UNREACH, code, 0); return; } - if (nf_ip_checksum(skb_in, hook, ip_hdrlen(skb_in), proto) == 0) + if (nf_ip_checksum(skb_in, hook, dataoff, proto) == 0) icmp_send(skb_in, ICMP_DEST_UNREACH, code, 0); } EXPORT_SYMBOL_GPL(nf_send_unreach); |