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windows-server-2003/net/tcpip/driver/ipsec/sys/ah.c

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/*++
Copyright (c) 1997-2001 Microsoft Corporation
Module Name:
ah.c
Abstract:
This module contains the code to create/verify Authentication Headers.
Author:
Sanjay Anand (SanjayAn) 2-January-1997
ChunYe
Environment:
Kernel mode
Revision History:
--*/
#include "precomp.h"
#ifdef RUN_WPP
#include "ah.tmh"
#endif
//
// This array assumes one-to-one correspondence with the algoIds and
// their order in ipsec.h.
//
#ifndef _TEST_PERF
AUTH_ALGO auth_algorithms[] = {
{ ah_nullinit, ah_nullupdate, ah_nullfinish, MD5DIGESTLEN},
{ ah_hmacmd5init, ah_hmacmd5update, ah_hmacmd5finish, MD5DIGESTLEN},
{ ah_hmacshainit, ah_hmacshaupdate, ah_hmacshafinish, A_SHA_DIGEST_LEN},
};
#else
AUTH_ALGO auth_algorithms[] = {
{ ah_nullinit, ah_nullupdate, ah_nullfinish, MD5DIGESTLEN},
{ ah_nullinit, ah_nullupdate, ah_nullfinish, MD5DIGESTLEN},
{ ah_nullinit, ah_nullupdate, ah_nullfinish, A_SHA_DIGEST_LEN},
};
#endif
NTSTATUS
IPSecCreateAH(
IN PUCHAR pIPHeader,
IN PVOID pData,
IN PVOID IPContext,
IN PSA_TABLE_ENTRY pSA,
IN ULONG Index,
OUT PVOID *ppNewData,
OUT PVOID *ppSCContext,
OUT PULONG pExtraBytes,
IN ULONG HdrSpace,
IN BOOLEAN fSrcRoute,
IN BOOLEAN fCryptoOnly
)
/*++
Routine Description:
Create the AH, given the packet. On the send side.
Arguments:
pIPHeader - points to start of IP header.
pData - points to the data after the IP header. PNDIS_BUFFER
pSA - Sec. Assoc. entry
ppNewData - the new MDL chain to be used by TCPIP
ppSCContext - send complete context used to clean up IPSEC headers
pExtraBytes - the header expansion caused by this IPSEC header
Return Value:
STATUS_SUCCESS
Others:
STATUS_INSUFFICIENT_RESOURCES
STATUS_UNSUCCESSFUL (error in algo.)
--*/
{
NTSTATUS status = STATUS_SUCCESS;
PNDIS_BUFFER pAHBuffer;
PNDIS_BUFFER pHdrBuf = NULL;
PNDIS_BUFFER pOptBuf = NULL;
AH UNALIGNED *pAH;
IPHeader UNALIGNED * pIPH;
ULONG hdrLen;
PIPSEC_SEND_COMPLETE_CONTEXT pContext;
PAUTH_ALGO pAlgo;
ULONG ahLen;
ULONG ipNext;
IPHeader UNALIGNED * pIPH2;
UCHAR pAHData[MAX_AH_OUTPUT_LEN];
ULONG totalBytes = 0;
ULONG saveFlags = 0;
ULONG Seq;
USHORT IPLength;
PNDIS_BUFFER pSaveDataLinkage = NDIS_BUFFER_LINKAGE((PNDIS_BUFFER)pData);
PNDIS_BUFFER pSaveOptLinkage = NULL;
BOOLEAN fOuterAH = ((pSA->sa_Flags & FLAGS_SA_TUNNEL) &&
(((Index == 1) && !pSA->COMP_ALGO(0)) || (Index == 2)));
BOOLEAN fTunnel = ((pSA->sa_Flags & FLAGS_SA_TUNNEL) &&
((Index == 0) || ((Index == 1) && pSA->COMP_ALGO(0))));
BOOLEAN fMuteDest = fSrcRoute && !fTunnel;
Interface * DestIF = (Interface *) IPContext;
IPSEC_DEBUG(LL_A, DBF_AH, ("Entering IPSecCreateAH"));
#if DBG
IPSEC_DEBUG(LL_A,DBF_MDL, ("Entering IPSecCreateAH"));
IPSEC_PRINT_CONTEXT(*ppSCContext);
IPSEC_PRINT_MDL(pData);
#endif
ASSERT(pSA->sa_Operation[Index] == Auth);
if (pSA->INT_ALGO(Index) > NUM_AUTH_ALGOS) {
return STATUS_INVALID_PARAMETER;
}
pAlgo = &(auth_algorithms[pSA->INT_ALGO(Index)]);
ahLen = sizeof(AH) + pSA->sa_TruncatedLen * sizeof(UCHAR);
//
// If ESP was done previously, then dont alloc the context since we
// can use the one alloced in ESP processing
//
if (*ppSCContext == NULL) {
pContext = IPSecAllocateSendCompleteCtx(IPSEC_TAG_AH);
if (!pContext) {
IPSEC_DEBUG(LL_A,DBF_AH, ("Failed to alloc. SendCtx"));
return STATUS_INSUFFICIENT_RESOURCES;
}
IPSEC_INCREMENT(g_ipsec.NumSends);
IPSecZeroMemory(pContext, sizeof(IPSEC_SEND_COMPLETE_CONTEXT));
#if DBG
RtlCopyMemory(pContext->Signature, "ISC1", 4);
#endif
*ppSCContext = pContext;
} else {
//
// Piggybacking on ESP Context
//
pContext = *ppSCContext;
saveFlags = pContext->Flags;
}
//
// Get buffer for AH since no space reserved in the stack. Allocate enough for
// the full hash, but hack the len to only truncated length.
//
IPSecAllocateBuffer(&status,
&pAHBuffer,
(PUCHAR *)&pAH,
ahLen+(pAlgo->OutputLen - pSA->sa_TruncatedLen),
IPSEC_TAG_AH);
if (!NT_SUCCESS(status)) {
IPSEC_DEBUG(LL_A,DBF_AH, ("Failed to alloc. AH MDL"));
pContext->Flags = saveFlags;
return status;
}
NdisAdjustBufferLength(pAHBuffer, ahLen);
pIPH = (IPHeader UNALIGNED *)pIPHeader;
hdrLen = (pIPH->iph_verlen & (UCHAR)~IP_VER_FLAG) << 2;
if (fTunnel) {
PNDIS_BUFFER pSrcOptBuf;
PUCHAR pOpt;
PUCHAR pSrcOpt;
ULONG optLen = 0;
IPSEC_DEBUG(LL_A,DBF_AH, ("AH Tunnel mode..."));
//
// Allocate an MDL for the new cleartext IP header
//
IPSecAllocateBuffer(&status,
&pHdrBuf,
(PUCHAR *)&pIPH2,
sizeof(IPHeader),
IPSEC_TAG_AH);
if (!NT_SUCCESS(status)) {
NTSTATUS ntstatus;
IPSEC_DEBUG(LL_A,DBF_AH, ("Failed to alloc. PAD MDL"));
IPSecFreeBuffer(&ntstatus, pAHBuffer);
pContext->Flags = saveFlags;
return status;
}
*pExtraBytes += ahLen + sizeof(IPHeader);
//
// if we are going to fragment, and were tunneling, then, copy over the options, if present.
// Also, use the original IP header on the outside and the new fabricated on the inside.
// This is to make sure we free headers appropriately on the send completes.
//
//
//
// Now hookup the MDLs
//
pContext->Flags |= SCF_AH_TU;
pContext->AHTuMdl = pAHBuffer;
pContext->PrevTuMdl = (PNDIS_BUFFER)pData;
pContext->OriTuMdl = NDIS_BUFFER_LINKAGE((PNDIS_BUFFER)pData);
NDIS_BUFFER_LINKAGE(pAHBuffer) = pHdrBuf;
if (hdrLen > sizeof(IPHeader)) {
if (HdrSpace < *pExtraBytes) {
IPSEC_DEBUG(LL_A,DBF_AH, ("Going to frag."));
pSrcOptBuf = NDIS_BUFFER_LINKAGE((PNDIS_BUFFER)pData);
pSaveOptLinkage = NDIS_BUFFER_LINKAGE(pSrcOptBuf);
IPSecQueryNdisBuf(pSrcOptBuf, &pSrcOpt, &optLen);
IPSecAllocateBuffer(&status,
&pOptBuf,
(PUCHAR *)&pOpt,
hdrLen - sizeof(IPHeader),
IPSEC_TAG_AH);
if (!NT_SUCCESS(status)) {
NTSTATUS ntstatus;
IPSEC_DEBUG(LL_A,DBF_AH, ("Failed to alloc. PAD MDL"));
NDIS_BUFFER_LINKAGE((PNDIS_BUFFER)pData) = pSaveDataLinkage;
IPSecFreeBuffer(&ntstatus, pAHBuffer);
IPSecFreeBuffer(&ntstatus, pHdrBuf);
pContext->Flags = saveFlags;
return status;
}
RtlCopyMemory(pOpt, pSrcOpt, hdrLen-sizeof(IPHeader));
pContext->OptMdl = pOptBuf;
IPSEC_DEBUG(LL_A,DBF_AH, ("Copying options. S: %p, D: %p",pSrcOptBuf, pOptBuf));
//
// replace the original Opt Mdl with ours.
//
NDIS_BUFFER_LINKAGE(pOptBuf) = NDIS_BUFFER_LINKAGE(pSrcOptBuf);
NDIS_BUFFER_LINKAGE(pHdrBuf) = pOptBuf;
IPSEC_DEBUG(LL_A,DBF_AH, ("Options; pointed Hdrbuf: %p to pOptBuf: %p", pHdrBuf, pOptBuf));
*pExtraBytes += hdrLen-sizeof(IPHeader);
} else {
IPSEC_DEBUG(LL_A,DBF_AH, ("Options; pointed Hdrbuf: %p to link(pData): %p", pHdrBuf, NDIS_BUFFER_LINKAGE((PNDIS_BUFFER)pData)));
NDIS_BUFFER_LINKAGE(pHdrBuf) = NDIS_BUFFER_LINKAGE((PNDIS_BUFFER)pData);
}
} else {
IPSEC_DEBUG(LL_A,DBF_AH, ("No options; pointed Hdrbuf: %p to link(pData): %p", pHdrBuf, NDIS_BUFFER_LINKAGE((PNDIS_BUFFER)pData)));
NDIS_BUFFER_LINKAGE(pHdrBuf) = NDIS_BUFFER_LINKAGE((PNDIS_BUFFER)pData);
}
NDIS_BUFFER_LINKAGE((PNDIS_BUFFER)pData) = pAHBuffer;
//
// xsum the new IP header since we expect that to be the case
// at this stage in tpt mode.
//
RtlCopyMemory(pIPH2, pIPH, sizeof(IPHeader));
//
// no options in the outer header; reset the len.
//
pIPH->iph_verlen = IP_VERSION + (sizeof(IPHeader) >> 2);
//
// also reset the frag. params.
//
pIPH->iph_offset &= ~(IP_MF_FLAG | IP_OFFSET_MASK);
if (DestIF->if_dfencap == ClearDfEncap) {
pIPH->iph_offset &= ~(IP_DF_FLAG | IP_OFFSET_MASK);
}
ASSERT(pSA->sa_TunnelAddr);
//
// Tunnel starts here; replace dest addr to point to Tunnel end if specified
// else tunnel ends at final dest
//
pIPH->iph_dest = pSA->sa_TunnelAddr;
//
// The first pended packet on a gateway (proxy negotiating for two subnets)
// would come via the transmit path. Hence the source address would not be
// kosher. We need to replace the src address in that case also.
// We get this from the corresponding inbound SA's tunnel addr.
//
pIPH->iph_src = pSA->sa_SrcTunnelAddr;
pIPH->iph_id = (ushort) TCPIP_GEN_IPID();
pIPH->iph_xsum = 0;
pIPH->iph_xsum = ~xsum(pIPH, sizeof(IPHeader));
//
// Set up headers so CreateHash works as in Tpt mode.
//
pIPHeader = (PUCHAR)pIPH;
*ppNewData = (PVOID)pData;
ipNext = ((UNALIGNED IPHeader *)pIPHeader)->iph_protocol;
pAH->ah_next = (UCHAR)IP_IN_IP;
} else {
*pExtraBytes += ahLen;
if (hdrLen > sizeof(IPHeader)) {
//
// Options present - chain AH after options
//
if (fOuterAH) {
pContext->Flags |= SCF_AH_2;
pContext->OriAHMdl2 = NDIS_BUFFER_LINKAGE(NDIS_BUFFER_LINKAGE((PNDIS_BUFFER)pData));
pContext->PrevAHMdl2 = NDIS_BUFFER_LINKAGE((PNDIS_BUFFER)pData);
pAHBuffer->Next = pContext->OriAHMdl2;
} else {
pContext->Flags |= SCF_AH;
pContext->OriAHMdl = NDIS_BUFFER_LINKAGE(NDIS_BUFFER_LINKAGE((PNDIS_BUFFER)pData));
pContext->PrevMdl = NDIS_BUFFER_LINKAGE((PNDIS_BUFFER)pData);
pAHBuffer->Next = pContext->OriAHMdl;
}
NDIS_BUFFER_LINKAGE(NDIS_BUFFER_LINKAGE((PNDIS_BUFFER)pData)) = pAHBuffer;
} else {
//
// Chain the AH buffer after IP header
//
if (fOuterAH) {
pContext->Flags |= SCF_AH_2;
pContext->OriAHMdl2 = NDIS_BUFFER_LINKAGE((PNDIS_BUFFER)pData);
pContext->PrevAHMdl2 = (PNDIS_BUFFER)pData;
pAHBuffer->Next = pContext->OriAHMdl2;
} else {
pContext->Flags |= SCF_AH;
pContext->OriAHMdl = NDIS_BUFFER_LINKAGE((PNDIS_BUFFER)pData);
pContext->PrevMdl = (PNDIS_BUFFER)pData;
pAHBuffer->Next = pContext->OriAHMdl;
}
NDIS_BUFFER_LINKAGE((PNDIS_BUFFER)pData) = pAHBuffer;
}
if (fOuterAH) {
pContext->AHMdl2 = pAHBuffer;
} else {
pContext->AHMdl = pAHBuffer;
}
pAH->ah_next = ((UNALIGNED IPHeader *)pIPHeader)->iph_protocol;
}
//
// Initialize the other fields of the AH header
//
pAH->ah_len = (UCHAR)((pSA->sa_TruncatedLen + pSA->sa_ReplayLen) >> 2);
pAH->ah_reserved = 0;
pAH->ah_spi = HOST_TO_NET_LONG(pSA->sa_OtherSPIs[Index]);
Seq = IPSEC_INCREMENT(pSA->sa_ReplaySendSeq[Index]);
pAH->ah_replay = HOST_TO_NET_LONG(Seq);
//
// Update the IP total length to reflect the AH header
//
IPLength = NET_SHORT(pIPH->iph_length) + (USHORT)ahLen;
if (fTunnel) {
IPLength += sizeof(IPHeader);
}
UpdateIPLength(pIPH, NET_SHORT(IPLength));
UpdateIPProtocol(pIPH, PROTOCOL_AH);
ADD_TO_LARGE_INTEGER(
&pSA->sa_Stats.AuthenticatedBytesSent,
NET_SHORT(pIPH->iph_length));
ADD_TO_LARGE_INTEGER(
&g_ipsec.Statistics.uAuthenticatedBytesSent,
NET_SHORT(pIPH->iph_length));
//
// Generate the Hash.
//
if (!fCryptoOnly) {
status = IPSecGenerateHash( pIPHeader,
(PVOID)pData,
pSA,
(PUCHAR)(pAH + 1),
fMuteDest,
FALSE, // not on recv path
pAlgo,
Index);
if (!NT_SUCCESS(status)) {
NTSTATUS ntstatus;
IPSEC_DEBUG(LL_A,DBF_AH, ("Failed to hash, pAH: %p", pAH));
NDIS_BUFFER_LINKAGE((PNDIS_BUFFER)pData) = pSaveDataLinkage;
if (pSaveOptLinkage) {
NDIS_BUFFER_LINKAGE(NDIS_BUFFER_LINKAGE((PNDIS_BUFFER)pData)) = pSaveOptLinkage;
}
IPSecFreeBuffer(&ntstatus, pAHBuffer);
if (pHdrBuf) {
IPSecFreeBuffer(&ntstatus, pHdrBuf);
}
if (pOptBuf) {
IPSecFreeBuffer(&ntstatus, pOptBuf);
}
pContext->Flags = saveFlags;
*ppNewData = NULL;
return status;
}
} else {
//
// Zero out the hash.
//
IPSecZeroMemory((PUCHAR)(pAH + 1), pSA->sa_TruncatedLen);
}
//
// Bump up the bytes transformed count.
//
ADD_TO_LARGE_INTEGER(
&pSA->sa_TotalBytesTransformed,
NET_SHORT(pIPH->iph_length));
//
// Return modified packet.
//
IPSEC_DEBUG(LL_A,DBF_AH, ("Exiting IPSecCreateAH, ahLen: %lx, status: %lx", ahLen, status));
#if DBG
IPSEC_DEBUG(LL_A,DBF_MDL, ("Exiting IPSecCreateAH"));
IPSEC_PRINT_CONTEXT(*ppSCContext);
if (*ppNewData) {
IPSEC_PRINT_MDL(*ppNewData);
}
else {
IPSEC_PRINT_MDL(pData);
}
#endif
return STATUS_SUCCESS;
}
NTSTATUS
IPSecVerifyAH(
IN PUCHAR *pIPHeader,
IN PVOID pData,
IN PSA_TABLE_ENTRY pSA,
IN ULONG Index,
OUT PULONG pExtraBytes,
IN BOOLEAN fSrcRoute,
IN BOOLEAN fCryptoDone,
IN BOOLEAN fFastRcv
)
/*++
Routine Description:
Verify the AH, given the packet. If AH kosher, strips off the AH from
pData.
Arguments:
pIPHeader - points to start of IP header.
pData - points to the data after the IP header.
pSA - Sec. Assoc. entry
pExtraBytes - out param to inform IP on recv path how many bytes IPSEC took off.
Return Value:
STATUS_SUCCESS
Others:
STATUS_UNSUCCESSFUL (packet not kosher - bad AH)
STATUS_INSUFFICIENT_RESOURCES
--*/
{
NTSTATUS status = STATUS_SUCCESS;
PUCHAR pPyld;
ULONG Len;
LONG ahLen;
LONG totalLen;
UCHAR Buf[MAX_AH_OUTPUT_LEN];
PUCHAR pAHData = Buf;
IPHeader UNALIGNED *pIPH = (IPHeader UNALIGNED *)*pIPHeader;
ULONG extraBytes = 0;
ULONG hdrLen;
PAUTH_ALGO pAlgo;
USHORT FilterFlags;
BOOLEAN fTunnel = ((pSA->sa_Flags & FLAGS_SA_TUNNEL) &&
((Index == 0) ||
((Index == 1) && (pSA->sa_Operation[0] == Compress))));
IPSEC_DEBUG(LL_A,DBF_AH, ("Entering IPSecVerifyAH"));
ASSERT(pSA->sa_Operation[Index] == Auth);
if (pSA->INT_ALGO(Index) > NUM_AUTH_ALGOS) {
return STATUS_INVALID_PARAMETER;
}
hdrLen = (pIPH->iph_verlen & (UCHAR)~IP_VER_FLAG) << 2;
pAlgo = &(auth_algorithms[pSA->INT_ALGO(Index)]);
ahLen = sizeof(AH) + pSA->sa_TruncatedLen * sizeof(UCHAR);
IPSEC_GET_TOTAL_LEN_RCV_BUF(pData, &totalLen);
//
// Do we have enough in the buffer?
//
if (totalLen < ahLen) {
return STATUS_INVALID_PARAMETER;
}
//
// Compare the hash with the AH from packet
// First buffer has the AH
//
IPSecQueryRcvBuf(pData, &pPyld, &Len);
//
// Size OK?
//
if (((UNALIGNED AH *)pPyld)->ah_len !=
(UCHAR)((pSA->sa_TruncatedLen + pSA->sa_ReplayLen) >> 2)) {
IPSEC_DEBUG(LL_A,DBF_AH, ("Failed size check: in: %x, need: %x",
((UNALIGNED AH *)pPyld)->ah_len,
(UCHAR)((pSA->sa_TruncatedLen + pSA->sa_ReplayLen) >> 2)));
return STATUS_INVALID_PARAMETER;
}
//
// Generate the Hash
//
if (!fCryptoDone) {
status = IPSecGenerateHash( *pIPHeader,
pData,
pSA,
pAHData,
fSrcRoute,
TRUE,
pAlgo,
Index); // on recv path
if (!NT_SUCCESS(status)) {
IPSEC_DEBUG(LL_A,DBF_AH, ("Failed to hash, pData: %p", pData));
return status;
}
if (!IPSecEqualMemory( pAHData,
pPyld + sizeof(AH),
pSA->sa_TruncatedLen)) {
IPSecBufferEvent( pIPH->iph_src,
EVENT_IPSEC_AUTH_FAILURE,
1,
TRUE);
IPSEC_DEBUG(LL_A,DBF_AH, ("Failed to compare, pPyld: %p, pAHData: %p", pPyld, pAHData));
IPSEC_DEBUG(LL_A,DBF_GENHASH, ("AHData: %lx-%lx-%lx",
*(ULONG *)&(pAHData)[0],
*(ULONG *)&(pAHData)[4],
*(ULONG *)&(pAHData)[8]));
IPSEC_DEBUG(LL_A,DBF_GENHASH, ("PyldHash: %lx-%lx-%lx",
*(ULONG *)&((UCHAR *)(pPyld + sizeof(AH)))[0],
*(ULONG *)&((UCHAR *)(pPyld + sizeof(AH)))[4],
*(ULONG *)&((UCHAR *)(pPyld + sizeof(AH)))[8]));
IPSEC_INC_STATISTIC(dwNumPacketsNotAuthenticated);
return IPSEC_INVALID_AH;
}
}
ADD_TO_LARGE_INTEGER(
&pSA->sa_Stats.AuthenticatedBytesReceived,
NET_SHORT(pIPH->iph_length));
ADD_TO_LARGE_INTEGER(
&g_ipsec.Statistics.uAuthenticatedBytesReceived,
NET_SHORT(pIPH->iph_length));
//
// Check the replay window
//
status=IPSecChkReplayWindow(
NET_TO_HOST_LONG(((UNALIGNED AH *)pPyld)->ah_replay),
pSA,
Index);
if (!NT_SUCCESS(status)) {
IPSEC_DEBUG(LL_A,DBF_AH, ("Replay check failed, pPyld: %p, pAHData: %p", pPyld, pAHData));
IPSEC_INC_STATISTIC(dwNumPacketsWithReplayDetection);
return status;
}
IPSEC_DEBUG(LL_A,DBF_AH, ("IP Len: %lx", pIPH->iph_length));
pIPH->iph_length = NET_SHORT(NET_SHORT(pIPH->iph_length) - (USHORT)ahLen);
IPSEC_DEBUG(LL_A,DBF_AH, ("IP Len: %lx", pIPH->iph_length));
//
// Restore the protocol from AH header
//
pIPH->iph_protocol = ((UNALIGNED AH *)pPyld)->ah_next;
IPSEC_DEBUG(LL_A,DBF_AH, ("Matched!! Restored protocol %x", pIPH->iph_protocol));
//
// Remove the AH from the packet
//
IPSEC_SET_OFFSET_IN_BUFFER(pData, ahLen);
//
// Move the IP header forward for filter/firewall hook, fast path only.
//
if (fFastRcv) {
IPSecMoveMemory(((PUCHAR)pIPH) + ahLen, (PUCHAR)pIPH, hdrLen);
*pIPHeader=(PUCHAR)pIPH+ahLen;
pIPH = (IPHeader UNALIGNED *)*pIPHeader;
}
extraBytes += ahLen;
//
// Bump up the bytes transformed count.
//
ADD_TO_LARGE_INTEGER(
&pSA->sa_TotalBytesTransformed,
NET_SHORT(pIPH->iph_length));
if (fTunnel) {
if (pIPH->iph_protocol != IP_IN_IP) {
IPSEC_DEBUG(LL_A,DBF_AH, ("BAD protocol in IP: %x", pIPH->iph_protocol));
return STATUS_INVALID_PARAMETER;
}
}
*pExtraBytes += extraBytes;
IPSEC_DEBUG(LL_A,DBF_AH, ("Exiting IPSecVerifyAH"));
return status;
}
NTSTATUS
IPSecGenerateHash(
IN PUCHAR pIPHeader,
IN PVOID pData,
IN PSA_TABLE_ENTRY pSA,
IN PUCHAR pAHData,
IN BOOLEAN fMuteDest,
IN BOOLEAN fIncoming,
IN PAUTH_ALGO pAlgo,
IN ULONG Index
)
/*++
Routine Description:
Arguments:
pIPHeader - points to start of IP header.
pData - points to the entire IP datagram, starting at the IP Header
pSA - Sec. Assoc. entry
pAHData - buffer to contain the generated hash
fIncoming - TRUE if on recv path.
pAlgo - the auth_algo being used
Return Value:
STATUS_SUCCESS
Others:
STATUS_UNSUCCESSFUL (packet not kosher - bad AH)
STATUS_INSUFFICIENT_RESOURCES
--*/
{
ULONG numBytesPayload;
ULONG i;
PUCHAR pPayload;
IPHeader UNALIGNED *pIPH = (UNALIGNED IPHeader *)pIPHeader;
PUCHAR pOptions;
PNDIS_BUFFER pBuf = (PNDIS_BUFFER)pData;
ULONG hdrLen;
ULONG ahLen;
NTSTATUS status;
ALGO_STATE State = {0};
BOOLEAN fTunnel = ( (pSA->sa_Flags & FLAGS_SA_TUNNEL) &&
((Index == 0) ||
((Index == 1) && (pSA->sa_Operation[0] == Compress))));
//
// These are saved since they can change enroute
//
//
// Scratch array used for AH calculation
//
UCHAR zero[MAX_IP_OPTION_SIZE];
UCHAR savetos; // Type of service.
USHORT saveoffset; // Flags and fragment offset.
UCHAR savettl; // Time to live.
USHORT savexsum; // Header checksum.
IPAddr savedest; // Dest address.
IPSEC_DEBUG(LL_A,DBF_AH, ("Entering IPSecGenerateHash"));
ahLen = sizeof(AH) + pSA->sa_TruncatedLen * sizeof(UCHAR);
State.as_sa = pSA;
IPSecZeroMemory(zero, sizeof(zero));
status = pAlgo->init(&State, Index);
if (!NT_SUCCESS(status)) {
IPSEC_DEBUG(LL_A,DBF_AH, ("init failed: %lx", status));
}
//
// Save, then zero out fields that can change enroute
//
savetos = pIPH->iph_tos;
saveoffset = pIPH->iph_offset;
savettl = pIPH->iph_ttl;
savexsum = pIPH->iph_xsum;
pIPH->iph_tos = 0;
pIPH->iph_offset = 0;
pIPH->iph_ttl = 0;
pIPH->iph_xsum = 0;
//
// Mute dest address as well if source routing
//
if (fMuteDest) {
savedest = pIPH->iph_dest;
pIPH->iph_dest = 0;
}
//
// Call MD5 to create the header hash
//
pAlgo->update(&State, pIPHeader, sizeof(IPHeader));
#if DBG
if (fIncoming) {
IPSEC_DEBUG(LL_A,DBF_GENHASH, ("IPHeader to Hash: %lx-%lx-%lx-%lx-%lx",
*(ULONG *)&(pIPHeader)[0],
*(ULONG *)&(pIPHeader)[4],
*(ULONG *)&(pIPHeader)[8],
*(ULONG *)&(pIPHeader)[12],
*(ULONG *)&(pIPHeader)[16]));
}
#endif
//
// Restore the zeroed fields
//
pIPH->iph_tos = savetos;
pIPH->iph_offset = saveoffset;
pIPH->iph_ttl = savettl;
pIPH->iph_xsum = savexsum;
//
// Restore dest address as well for source routing
//
if (fMuteDest) {
pIPH->iph_dest = savedest;
}
//
// Now, do the options if they exist
//
hdrLen = (pIPH->iph_verlen & (UCHAR)~IP_VER_FLAG) << 2;
if (hdrLen > sizeof(IPHeader)) {
UCHAR cLength;
ULONG uIndex = 0;
ULONG uOptLen = hdrLen - sizeof(IPHeader);
ASSERT(!fTunnel);
if (fIncoming) {
pOptions = (PUCHAR)(pIPH + 1);
} else {
//
// Options are in second MDL... on send side
//
pBuf = NDIS_BUFFER_LINKAGE(pBuf);
IPSecQueryNdisBuf(pBuf, &pOptions, &uOptLen);
}
IPSEC_DEBUG(LL_A,DBF_AH, ("Got options: %p", pOptions));
//
// Some options may need to be zeroed out...
//
while (uIndex < uOptLen) {
switch (*pOptions) {
case IP_OPT_EOL:
pAlgo->update(&State, zero, 1);
uIndex = uOptLen;
break;
//
// Zeroed for AH calculation
//
case IP_OPT_NOP:
pAlgo->update(&State, zero, 1);
uIndex++;
pOptions++;
break;
case IP_OPT_LSRR:
case IP_OPT_SSRR:
case IP_OPT_RR:
case IP_OPT_TS:
cLength = pOptions[IP_OPT_LENGTH];
pAlgo->update(&State, zero, cLength);
uIndex += cLength;
pOptions += cLength;
break;
//
// Assumed invariant; used for AH calc
//
case IP_OPT_ROUTER_ALERT:
case IP_OPT_SECURITY:
default:
cLength = pOptions[IP_OPT_LENGTH];
pAlgo->update(&State, pOptions, cLength);
uIndex += cLength;
pOptions += cLength;
break;
}
}
}
//
// Go over the remaining payload, creating the hash
//
// NOTE: We differentiate between the send and recv since the
// buffer formats are different
//
if (fIncoming) {
IPRcvBuf *pRcvBuf = (IPRcvBuf *)pData;
ULONG Len;
LONG remainLen;
UCHAR UNALIGNED *pPyld;
//
// First buffer shd be the AH itself
//
IPSecQueryRcvBuf(pRcvBuf, &pPyld, &Len);
//
// Do the first portion of the header.
//
pAlgo->update(&State, pPyld, sizeof(AH));
#if DBG
if (fIncoming) {
IPSEC_DEBUG(LL_A,DBF_GENHASH, ("AHHeader to Hash: %lx-%lx-%lx",
*(ULONG *)&(pPyld)[0],
*(ULONG *)&(pPyld)[4],
*(ULONG *)&(pPyld)[8]));
}
#endif
//
// The authentication data should be considered as 0.
// In our case, the data length is fixed at pSA->sa_TruncatedLen bytes
//
pAlgo->update(&State, zero, pSA->sa_TruncatedLen);
//
// Jump over the remaining AH: need to take care of situations
// where ICV is chained (Raid 146275).
//
if (((LONG)Len - (LONG)ahLen) >= 0) {
pPyld += ahLen;
IPSEC_DEBUG(LL_A,DBF_AH, ("Jumped over IPSEC res: %p, len: %lx", pPyld, Len));
//
// Tpt header is right after AH
//
pAlgo->update(&State, pPyld, Len - ahLen);
} else {
//
// Need to jump over ICV if it expands over multiple buffers
//
remainLen = pSA->sa_TruncatedLen - (Len - sizeof(AH));
IPSEC_DEBUG(LL_A,DBF_AH, ("Jumped over IPSEC res: %p, remainlen: %lx", pPyld, remainLen));
while (remainLen > 0 && (pRcvBuf = IPSEC_BUFFER_LINKAGE(pRcvBuf))) {
IPSecQueryRcvBuf(pRcvBuf, &pPyld, &Len);
remainLen -= Len;
}
//
// Do the possible partial data after AH
//
if (remainLen < 0 && pRcvBuf) {
pPyld += Len + remainLen;
pAlgo->update(&State, pPyld, -remainLen);
}
}
//
// Now do the remaining chain
//
while (pRcvBuf = IPSEC_BUFFER_LINKAGE(pRcvBuf)) {
IPSecQueryRcvBuf(pRcvBuf, &pPyld, &Len);
pAlgo->update(&State, pPyld, Len);
}
} else {
UCHAR UNALIGNED *pPyld;
ULONG Len;
//
// Second (or third if options present) buffer shd be the AH itself
//
pBuf = NDIS_BUFFER_LINKAGE(pBuf);
IPSecQueryNdisBuf(pBuf, &pPyld, &Len);
//
// Do the first portion of the header.
//
pAlgo->update(&State, pPyld, sizeof(AH));
//
// The authentication data should be considered as 0.
// In our case, the data length is fixed at pSA->sa_TruncatedLen bytes
//
pAlgo->update(&State, zero, pSA->sa_TruncatedLen);
//
// Skip over the remaining AH section
//
pPyld += ahLen;
IPSEC_DEBUG(LL_A,DBF_AH, ("Jumped over IPSEC Len: %lx, hdrlen: %lx", Len, hdrLen));
pAlgo->update(&State, pPyld, Len - ahLen);
//
// Now do the remaining chain
//
while (pBuf = NDIS_BUFFER_LINKAGE(pBuf)) {
IPSecQueryNdisBuf(pBuf, &pPyld, &Len);
pAlgo->update(&State, pPyld, Len);
}
}
pAlgo->finish(&State, pAHData, Index);
//
// Copy out the hash - get the truncated hash out, then zero out the rest
//
TRUNCATE(pAHData, pAHData, pSA->sa_TruncatedLen, MD5DIGESTLEN);
IPSEC_DEBUG(LL_A,DBF_AH, ("Exiting IPSecGenerateMD5"));
return STATUS_SUCCESS;
}