@@ -5,6 +5,7 @@
#include <linux/skbuff.h>
#include <net/ip.h>
#include <net/icmp.h>
+#include <net/netfilter/nf_reject.h>
void nf_send_unreach(struct sk_buff *skb_in, int code, int hook);
void nf_send_reset(struct net *net, struct sk_buff *oldskb, int hook);
@@ -3,6 +3,7 @@
#define _IPV6_NF_REJECT_H
#include <linux/icmpv6.h>
+#include <net/netfilter/nf_reject.h>
void nf_send_unreach6(struct net *net, struct sk_buff *skb_in, unsigned char code,
unsigned int hooknum);
new file mode 100644
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _NF_REJECT_H
+#define _NF_REJECT_H
+
+static inline bool nf_reject_verify_csum(__u8 proto) {
+ /* Skip protocols that don't use 16-bit one's complement checksum
+ * of the entire payload.
+ */
+ switch (proto) {
+ /* Protocols with other integrity checks. */
+ case IPPROTO_AH:
+ case IPPROTO_ESP:
+ case IPPROTO_SCTP:
+
+ /* Protocols with partial checksums. */
+ case IPPROTO_UDPLITE:
+ case IPPROTO_DCCP:
+
+ /* Protocols with optional checksums. */
+ case IPPROTO_GRE:
+ return false;
+ }
+ return true;
+}
+
+#endif /* _NF_REJECT_H */
@@ -125,13 +125,10 @@ static void nft_reject_br_send_v4_unreach(struct net *net,
if (pskb_trim_rcsum(oldskb, ntohs(ip_hdr(oldskb)->tot_len)))
return;
- if (ip_hdr(oldskb)->protocol == IPPROTO_TCP ||
- ip_hdr(oldskb)->protocol == IPPROTO_UDP)
- proto = ip_hdr(oldskb)->protocol;
- else
- proto = 0;
+ proto = ip_hdr(oldskb)->protocol;
if (!skb_csum_unnecessary(oldskb) &&
+ nf_reject_verify_csum(proto) &&
nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), proto))
return;
@@ -234,6 +231,9 @@ static bool reject6_br_csum_ok(struct sk_buff *skb, int hook)
if (thoff < 0 || thoff >= skb->len || (fo & htons(~0x7)) != 0)
return false;
+ if (!nf_reject_verify_csum(proto))
+ return true;
+
return nf_ip6_checksum(skb, hook, thoff, proto) == 0;
}
@@ -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);
}
@@ -233,6 +233,9 @@ static bool reject6_csum_ok(struct sk_buff *skb, int hook)
if (thoff < 0 || thoff >= skb->len || (fo & htons(~0x7)) != 0)
return false;
+ if (!nf_reject_verify_csum(proto))
+ return true;
+
return nf_ip6_checksum(skb, hook, thoff, proto) == 0;
}