linux/net/ipv4/netfilter
Florian Westphal db99b2f2b3 netfilter: nf_reject: don't reply to icmp error messages
tcp reject code won't reply to a tcp reset.

But the icmp reject 'netdev' family versions will reply to icmp
dst-unreach errors, unlike icmp_send() and icmp6_send() which are used
by the inet family implementation (and internally by the REJECT target).

Check for the icmp(6) type and do not respond if its an unreachable error.

Without this, something like 'ip protocol icmp reject', when used
in a netdev chain attached to 'lo', cause a packet loop.

Same for two hosts that both use such a rule: each error packet
will be replied to.

Such situation persist until the (bogus) rule is amended to ratelimit or
checks the icmp type before the reject statement.

As the inet versions don't do this make the netdev ones follow along.

Signed-off-by: Florian Westphal <fw@strlen.de>
2025-09-11 15:40:55 +02:00
..
Kconfig netfilter: add back NETFILTER_XTABLES dependencies 2025-08-07 13:19:25 +02:00
Makefile
arp_tables.c netfilter: Use kmemdup_array instead of kmemdup for multiple allocation 2024-09-03 10:47:16 +02:00
arpt_mangle.c
arptable_filter.c
ip_tables.c netfilter: nf_dup{4, 6}: Move duplication check to task_struct 2025-05-23 13:57:12 +02:00
ipt_ECN.c
ipt_REJECT.c
ipt_SYNPROXY.c
ipt_ah.c
ipt_rpfilter.c ipv4: Convert ->flowi4_tos to dscp_t. 2025-08-26 17:34:31 -07:00
iptable_filter.c
iptable_mangle.c
iptable_nat.c netfilter: iptables: Fix null-ptr-deref in iptable_nat_table_init(). 2024-07-31 23:20:50 +02:00
iptable_raw.c
iptable_security.c
nf_defrag_ipv4.c
nf_dup_ipv4.c ipv4: Convert ->flowi4_tos to dscp_t. 2025-08-26 17:34:31 -07:00
nf_nat_h323.c
nf_nat_pptp.c
nf_nat_snmp_basic.asn1
nf_nat_snmp_basic_main.c
nf_reject_ipv4.c netfilter: nf_reject: don't reply to icmp error messages 2025-09-11 15:40:55 +02:00
nf_socket_ipv4.c tcp: Don't pass hashinfo to socket lookup helpers. 2025-08-25 17:53:35 -07:00
nf_tproxy_ipv4.c tcp: Don't pass hashinfo to socket lookup helpers. 2025-08-25 17:53:35 -07:00
nft_dup_ipv4.c netfilter: nf_tables: pass context structure to nft_parse_register_load 2024-08-20 12:37:24 +02:00
nft_fib_ipv4.c ipv4: Convert ->flowi4_tos to dscp_t. 2025-08-26 17:34:31 -07:00
nft_reject_ipv4.c