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src/Cedar/Proto_IKE.c: ignore packets with no IPSec SA

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many thanks to Jonathan Phillibert from Amazon Web Services
for investigating and reporting that responding to such packets
might lead to traffic amplification
This commit is contained in:
Ilia Shipitsin 2024-06-22 18:53:35 +02:00
parent 4fe5352931
commit 6f57449164
1 changed files with 4 additions and 30 deletions
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34
src/Cedar/Proto_IKE.c
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@ -463,39 +463,13 @@ void ProcIPsecEspPacketRecv(IKE_SERVER *ike, UDPPACKET *p)
seq = READ_UINT(src + sizeof(UINT)); seq = READ_UINT(src + sizeof(UINT));
// Search and retrieve the IPsec SA from SPI // Search and retrieve the IPsec SA from SPI
// thank to @phillibert report, responding to bad SA might lead to amplification
// according to RFC4303 we should drop such packets
ipsec_sa = SearchClientToServerIPsecSaBySpi(ike, spi); ipsec_sa = SearchClientToServerIPsecSaBySpi(ike, spi);
if (ipsec_sa == NULL) if (ipsec_sa == NULL)
{ {
// Invalid SPI
UINT64 init_cookie = Rand64();
UINT64 resp_cookie = 0;
IKE_CLIENT *c = NULL;
IKE_CLIENT t;
Copy(&t.ClientIP, &p->SrcIP, sizeof(IP));
t.ClientPort = p->SrcPort;
Copy(&t.ServerIP, &p->DstIP, sizeof(IP));
t.ServerPort = p->DestPort;
t.CurrentIkeSa = NULL;
if (p->DestPort == IPSEC_PORT_IPSEC_ESP_RAW)
{
t.ClientPort = t.ServerPort = IPSEC_PORT_IPSEC_ISAKMP;
}
c = Search(ike->ClientList, &t);
if (c != NULL && c->CurrentIkeSa != NULL)
{
init_cookie = c->CurrentIkeSa->InitiatorCookie;
resp_cookie = c->CurrentIkeSa->ResponderCookie;
}
SendInformationalExchangePacketEx(ike, (c == NULL ? &t : c), IkeNewNoticeErrorInvalidSpiPayload(spi), false,
init_cookie, resp_cookie);
SendDeleteIPsecSaPacket(ike, (c == NULL ? &t : c), spi);
return; return;
} }