From: Eyal Birger eyal.birger@gmail.com
[ Upstream commit 61177e911dad660df86a4553eb01c95ece2f6a82 ]
Commit 8303b7e8f018 ("netfilter: nat: fix spurious connection timeouts") made nf_nat_icmp_reply_translation() use icmp_manip_pkt() as the l4 manipulation function for the outer packet on ICMP errors.
However, icmp_manip_pkt() assumes the packet has an 'id' field which is not correct for all types of ICMP messages.
This is not correct for ICMP error packets, and leads to bogus bytes being written the ICMP header, which can be wrongfully regarded as 'length' bytes by RFC 4884 compliant receivers.
Fix by assigning the 'id' field only for ICMP messages that have this semantic.
Reported-by: Shmulik Ladkani shmulik.ladkani@gmail.com Fixes: 8303b7e8f018 ("netfilter: nat: fix spurious connection timeouts") Signed-off-by: Eyal Birger eyal.birger@gmail.com Acked-by: Florian Westphal fw@strlen.de Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/netfilter/nf_nat_proto.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)
diff --git a/net/netfilter/nf_nat_proto.c b/net/netfilter/nf_nat_proto.c index 0a59c14b51776..64eedc17037ad 100644 --- a/net/netfilter/nf_nat_proto.c +++ b/net/netfilter/nf_nat_proto.c @@ -233,6 +233,19 @@ icmp_manip_pkt(struct sk_buff *skb, return false;
hdr = (struct icmphdr *)(skb->data + hdroff); + switch (hdr->type) { + case ICMP_ECHO: + case ICMP_ECHOREPLY: + case ICMP_TIMESTAMP: + case ICMP_TIMESTAMPREPLY: + case ICMP_INFO_REQUEST: + case ICMP_INFO_REPLY: + case ICMP_ADDRESS: + case ICMP_ADDRESSREPLY: + break; + default: + return true; + } inet_proto_csum_replace2(&hdr->checksum, skb, hdr->un.echo.id, tuple->src.u.icmp.id, false); hdr->un.echo.id = tuple->src.u.icmp.id;