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date: Sat, 16 Aug 2008 07:40:00 -0700,
group: microsoft.public.platformsdk.security
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SSH key exchange
I am trying to implement SSH transport layer using crypto API and i have an
issue. Specifically my problem is that when i pass the server, my DH public
key i.e client computed 'e' the server disconnects the connection. The
SSH_MSG_KEXDH_INIT message containing the public key which the MS DH provider
gives me is this
char peer0_2[] = {
0x00, 0x00, 0x00, 0x8c, 0x0a, 0x1e, 0xb1, 0x69,
0xeb, 0x6d, 0xc8, 0xe9, 0xd2, 0xd1, 0xc7, 0x5f,
0xab, 0x6d, 0x44, 0x40, 0x94, 0x56, 0x51, 0xdf,
0xce, 0x9c, 0xac, 0x02, 0x01, 0x0b, 0x48, 0xdb,
0xb0, 0xda, 0xd0, 0xdf, 0x43, 0xec, 0x34, 0x67,
0xca, 0xdd, 0x65, 0xfd, 0xb6, 0x08, 0x3c, 0xb1,
0x6f, 0xd6, 0x41, 0xba, 0x85, 0x21, 0xe5, 0xe0,
0xb9, 0xe2, 0x1b, 0xf9, 0x76, 0x5e, 0x26, 0xb1,
0xfb, 0x9d, 0x58, 0xef, 0x76, 0xa2, 0x77, 0x20,
0xff, 0x4d, 0x45, 0x71, 0x03, 0xff, 0xf8, 0x84,
0xa1, 0xb5, 0xc3, 0x6b, 0xca, 0xdf, 0x81, 0x98,
0xb7, 0xa6, 0xd7, 0xc7, 0x8c, 0x85, 0xec, 0xfc,
0x63, 0x7c, 0xbe, 0x39, 0x0f, 0x1c, 0xc7, 0x8a,
0x73, 0xcc, 0x7f, 0x4d, 0x80, 0xb2, 0x1b, 0x87,
0x33, 0x60, 0x8a, 0x7b, 0xd0, 0x60, 0x89, 0x90,
0x9c, 0x93, 0x73, 0xdb, 0x13, 0x79, 0xe9, 0x67,
0x30, 0x8d, 0xd7, 0xcb, 0xe9, 0x85, 0x8f, 0xf0,
0x19, 0xec, 0xef, 0x19, 0x18, 0xfd, 0x1d, 0xf8 };
And the server responds back with "unexpected end of packet". I see that
with some other ssh client programs the SSH_MSG_KEXDH_INIT is very small and
"always" looks like this:
00 00 00 0c 06 1e 00 00 08 00 1e 42 53 7b 43 76
any ideas/pointers as to where i am going wrong ?
date: Sat, 16 Aug 2008 07:40:00 -0700
author: Neelabh Mam
RE: SSH key exchange
small correction. MS DH provider does not give me the SSH_MSG_KEXDH_INIT
message, I extract the 'y' of the key and then construct the
SSH_MSG_KEXDH_INIT roughly like this:
CryptExportKey(hKeyClient,NULL,PUBLICKEYBLOB,0,NULL,&lenClientkeyBlob);
pClientPubKeyBlob = (PBYTE)calloc(lenClientkeyBlob,1);
CryptExportKey(hKeyClient,NULL,PUBLICKEYBLOB,0,pClientPubKeyBlob,&lenClientkeyBlob))
eClient = (PBYTE)calloc(1024,1);
eLen = lenClientkeyBlob - (sizeof(PUBLICKEYSTRUC)+sizeof(DHPUBKEY));
memmove(eClient,pClientPubKeyBlob+sizeof(PUBLICKEYSTRUC)+sizeof(DHPUBKEY),eLen);
"Neelabh Mam" wrote:
> I am trying to implement SSH transport layer using crypto API and i have an
> issue. Specifically my problem is that when i pass the server, my DH public
> key i.e client computed 'e' the server disconnects the connection. The
> SSH_MSG_KEXDH_INIT message containing the public key which the MS DH provider
> gives me is this
>
> char peer0_2[] = {
> 0x00, 0x00, 0x00, 0x8c, 0x0a, 0x1e, 0xb1, 0x69,
> 0xeb, 0x6d, 0xc8, 0xe9, 0xd2, 0xd1, 0xc7, 0x5f,
> 0xab, 0x6d, 0x44, 0x40, 0x94, 0x56, 0x51, 0xdf,
> 0xce, 0x9c, 0xac, 0x02, 0x01, 0x0b, 0x48, 0xdb,
> 0xb0, 0xda, 0xd0, 0xdf, 0x43, 0xec, 0x34, 0x67,
> 0xca, 0xdd, 0x65, 0xfd, 0xb6, 0x08, 0x3c, 0xb1,
> 0x6f, 0xd6, 0x41, 0xba, 0x85, 0x21, 0xe5, 0xe0,
> 0xb9, 0xe2, 0x1b, 0xf9, 0x76, 0x5e, 0x26, 0xb1,
> 0xfb, 0x9d, 0x58, 0xef, 0x76, 0xa2, 0x77, 0x20,
> 0xff, 0x4d, 0x45, 0x71, 0x03, 0xff, 0xf8, 0x84,
> 0xa1, 0xb5, 0xc3, 0x6b, 0xca, 0xdf, 0x81, 0x98,
> 0xb7, 0xa6, 0xd7, 0xc7, 0x8c, 0x85, 0xec, 0xfc,
> 0x63, 0x7c, 0xbe, 0x39, 0x0f, 0x1c, 0xc7, 0x8a,
> 0x73, 0xcc, 0x7f, 0x4d, 0x80, 0xb2, 0x1b, 0x87,
> 0x33, 0x60, 0x8a, 0x7b, 0xd0, 0x60, 0x89, 0x90,
> 0x9c, 0x93, 0x73, 0xdb, 0x13, 0x79, 0xe9, 0x67,
> 0x30, 0x8d, 0xd7, 0xcb, 0xe9, 0x85, 0x8f, 0xf0,
> 0x19, 0xec, 0xef, 0x19, 0x18, 0xfd, 0x1d, 0xf8 };
>
> And the server responds back with "unexpected end of packet". I see that
> with some other ssh client programs the SSH_MSG_KEXDH_INIT is very small and
> "always" looks like this:
>
> 00 00 00 0c 06 1e 00 00 08 00 1e 42 53 7b 43 76
>
> any ideas/pointers as to where i am going wrong ?
>
>
>
date: Sat, 16 Aug 2008 07:59:02 -0700
author: Neelabh Mam
RE: SSH key exchange
Ok, as of now ssh servers have started accepting my MSCAPI 'e'. i found out
that i missed to include some mandatory alogorithims in my KEXINIT message
but more important was e not being sent in proper mpint format. thanks.
observations on what might be in store, beyond keyexchange are welcome !
"Neelabh Mam" wrote:
> small correction. MS DH provider does not give me the SSH_MSG_KEXDH_INIT
> message, I extract the 'y' of the key and then construct the
> SSH_MSG_KEXDH_INIT roughly like this:
>
> CryptExportKey(hKeyClient,NULL,PUBLICKEYBLOB,0,NULL,&lenClientkeyBlob);
> pClientPubKeyBlob = (PBYTE)calloc(lenClientkeyBlob,1);
>
> CryptExportKey(hKeyClient,NULL,PUBLICKEYBLOB,0,pClientPubKeyBlob,&lenClientkeyBlob))
>
> eClient = (PBYTE)calloc(1024,1);
> eLen = lenClientkeyBlob - (sizeof(PUBLICKEYSTRUC)+sizeof(DHPUBKEY));
> memmove(eClient,pClientPubKeyBlob+sizeof(PUBLICKEYSTRUC)+sizeof(DHPUBKEY),eLen);
>
>
> "Neelabh Mam" wrote:
>
> > I am trying to implement SSH transport layer using crypto API and i have an
> > issue. Specifically my problem is that when i pass the server, my DH public
> > key i.e client computed 'e' the server disconnects the connection. The
> > SSH_MSG_KEXDH_INIT message containing the public key which the MS DH provider
> > gives me is this
> >
> > char peer0_2[] = {
> > 0x00, 0x00, 0x00, 0x8c, 0x0a, 0x1e, 0xb1, 0x69,
> > 0xeb, 0x6d, 0xc8, 0xe9, 0xd2, 0xd1, 0xc7, 0x5f,
> > 0xab, 0x6d, 0x44, 0x40, 0x94, 0x56, 0x51, 0xdf,
> > 0xce, 0x9c, 0xac, 0x02, 0x01, 0x0b, 0x48, 0xdb,
> > 0xb0, 0xda, 0xd0, 0xdf, 0x43, 0xec, 0x34, 0x67,
> > 0xca, 0xdd, 0x65, 0xfd, 0xb6, 0x08, 0x3c, 0xb1,
> > 0x6f, 0xd6, 0x41, 0xba, 0x85, 0x21, 0xe5, 0xe0,
> > 0xb9, 0xe2, 0x1b, 0xf9, 0x76, 0x5e, 0x26, 0xb1,
> > 0xfb, 0x9d, 0x58, 0xef, 0x76, 0xa2, 0x77, 0x20,
> > 0xff, 0x4d, 0x45, 0x71, 0x03, 0xff, 0xf8, 0x84,
> > 0xa1, 0xb5, 0xc3, 0x6b, 0xca, 0xdf, 0x81, 0x98,
> > 0xb7, 0xa6, 0xd7, 0xc7, 0x8c, 0x85, 0xec, 0xfc,
> > 0x63, 0x7c, 0xbe, 0x39, 0x0f, 0x1c, 0xc7, 0x8a,
> > 0x73, 0xcc, 0x7f, 0x4d, 0x80, 0xb2, 0x1b, 0x87,
> > 0x33, 0x60, 0x8a, 0x7b, 0xd0, 0x60, 0x89, 0x90,
> > 0x9c, 0x93, 0x73, 0xdb, 0x13, 0x79, 0xe9, 0x67,
> > 0x30, 0x8d, 0xd7, 0xcb, 0xe9, 0x85, 0x8f, 0xf0,
> > 0x19, 0xec, 0xef, 0x19, 0x18, 0xfd, 0x1d, 0xf8 };
> >
> > And the server responds back with "unexpected end of packet". I see that
> > with some other ssh client programs the SSH_MSG_KEXDH_INIT is very small and
> > "always" looks like this:
> >
> > 00 00 00 0c 06 1e 00 00 08 00 1e 42 53 7b 43 76
> >
> > any ideas/pointers as to where i am going wrong ?
> >
> >
> >
date: Sun, 17 Aug 2008 03:56:01 -0700
author: Neelabh Mam
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