diff options
Diffstat (limited to 'source4/libcli/auth')
-rw-r--r-- | source4/libcli/auth/schannel.c | 309 | ||||
-rw-r--r-- | source4/libcli/auth/schannel.h | 35 |
2 files changed, 344 insertions, 0 deletions
diff --git a/source4/libcli/auth/schannel.c b/source4/libcli/auth/schannel.c new file mode 100644 index 0000000000..e5a786ff24 --- /dev/null +++ b/source4/libcli/auth/schannel.c @@ -0,0 +1,309 @@ +/* + Unix SMB/CIFS implementation. + + schannel library code + + Copyright (C) Andrew Tridgell 2004 + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. +*/ + +#include "includes.h" + +/******************************************************************* + Encode or Decode the sequence number (which is symmetric) + ********************************************************************/ +static void netsec_deal_with_seq_num(struct schannel_state *state, + const uchar packet_digest[8], + uchar seq_num[8]) +{ + static const uchar zeros[4]; + uchar sequence_key[16]; + uchar digest1[16]; + + hmac_md5(state->session_key, zeros, sizeof(zeros), digest1); + hmac_md5(digest1, packet_digest, 8, sequence_key); + SamOEMhash(seq_num, sequence_key, 8); + + state->seq_num++; +} + + +/******************************************************************* + Calculate the key with which to encode the data payload + ********************************************************************/ +static void netsec_get_sealing_key(const uchar session_key[16], + const uchar seq_num[8], + uchar sealing_key[16]) +{ + static const uchar zeros[4]; + uchar digest2[16]; + uchar sess_kf0[16]; + int i; + + for (i = 0; i < 16; i++) { + sess_kf0[i] = session_key[i] ^ 0xf0; + } + + hmac_md5(sess_kf0, zeros, 4, digest2); + hmac_md5(digest2, seq_num, 8, sealing_key); +} + + +/******************************************************************* + Create a digest over the entire packet (including the data), and + MD5 it with the session key. + ********************************************************************/ +static void schannel_digest(const uchar sess_key[16], + const uchar netsec_sig[8], + const uchar *confounder, + const uchar *data, size_t data_len, + uchar digest_final[16]) +{ + uchar packet_digest[16]; + static const uchar zeros[4]; + struct MD5Context ctx; + + MD5Init(&ctx); + MD5Update(&ctx, zeros, 4); + MD5Update(&ctx, netsec_sig, 8); + if (confounder) { + MD5Update(&ctx, confounder, 8); + } + MD5Update(&ctx, data, data_len); + MD5Final(packet_digest, &ctx); + + hmac_md5(sess_key, packet_digest, sizeof(packet_digest), digest_final); +} + + +/* + unseal a packet +*/ +NTSTATUS schannel_unseal_packet(struct schannel_state *state, + uchar *data, size_t length, + DATA_BLOB *sig) +{ + uchar digest_final[16]; + uchar confounder[8]; + uchar seq_num[8]; + uchar sealing_key[16]; + static const uchar netsec_sig[8] = NETSEC_SEAL_SIGNATURE; + + if (sig->length != 32) { + return NT_STATUS_ACCESS_DENIED; + } + + memcpy(confounder, sig->data+24, 8); + + RSIVAL(seq_num, 0, state->seq_num); + SIVAL(seq_num, 4, state->initiator?0:0x80); + + netsec_get_sealing_key(state->session_key, seq_num, sealing_key); + SamOEMhash(confounder, sealing_key, 8); + SamOEMhash(data, sealing_key, length); + + schannel_digest(state->session_key, + netsec_sig, confounder, + data, length, digest_final); + + if (memcmp(digest_final, sig->data+16, 8) != 0) { + dump_data_pw("calc digest:", digest_final, 8); + dump_data_pw("wire digest:", sig->data+16, 8); + return NT_STATUS_ACCESS_DENIED; + } + + netsec_deal_with_seq_num(state, digest_final, seq_num); + + if (memcmp(seq_num, sig->data+8, 8) != 0) { + dump_data_pw("calc seq num:", seq_num, 8); + dump_data_pw("wire seq num:", sig->data+8, 8); + return NT_STATUS_ACCESS_DENIED; + } + + return NT_STATUS_OK; +} + +/* + check the signature on a packet +*/ +NTSTATUS schannel_check_packet(struct schannel_state *state, + const uchar *data, size_t length, + const DATA_BLOB *sig) +{ + uchar digest_final[16]; + uchar seq_num[8]; + static const uchar netsec_sig[8] = NETSEC_SIGN_SIGNATURE; + + if (sig->length != 32) { + return NT_STATUS_ACCESS_DENIED; + } + + RSIVAL(seq_num, 0, state->seq_num); + SIVAL(seq_num, 4, state->initiator?0:0x80); + + dump_data_pw("seq_num:\n", seq_num, 8); + dump_data_pw("sess_key:\n", state->session_key, 16); + + schannel_digest(state->session_key, + netsec_sig, NULL, + data, length, digest_final); + + netsec_deal_with_seq_num(state, digest_final, seq_num); + + if (memcmp(seq_num, sig->data+8, 8) != 0) { + dump_data_pw("calc seq num:", seq_num, 8); + dump_data_pw("wire seq num:", sig->data+8, 8); + return NT_STATUS_ACCESS_DENIED; + } + + if (memcmp(digest_final, sig->data+16, 8) != 0) { + dump_data_pw("calc digest:", digest_final, 8); + dump_data_pw("wire digest:", sig->data+16, 8); + return NT_STATUS_ACCESS_DENIED; + } + + return NT_STATUS_OK; +} + + +/* + seal a packet +*/ +NTSTATUS schannel_seal_packet(struct schannel_state *state, + uchar *data, size_t length, + DATA_BLOB *sig) +{ + uchar digest_final[16]; + uchar confounder[8]; + uchar seq_num[8]; + uchar sealing_key[16]; + static const uchar netsec_sig[8] = NETSEC_SEAL_SIGNATURE; + + generate_random_buffer(confounder, 8, False); + + RSIVAL(seq_num, 0, state->seq_num); + SIVAL(seq_num, 4, state->initiator?0x80:0); + + schannel_digest(state->session_key, + netsec_sig, confounder, + data, length, digest_final); + + netsec_get_sealing_key(state->session_key, seq_num, sealing_key); + SamOEMhash(confounder, sealing_key, 8); + SamOEMhash(data, sealing_key, length); + + netsec_deal_with_seq_num(state, digest_final, seq_num); + + if (!state->signature.data) { + state->signature = data_blob_talloc(state->mem_ctx, NULL, 32); + if (!state->signature.data) { + return NT_STATUS_NO_MEMORY; + } + } + (*sig) = state->signature; + + memcpy(sig->data, netsec_sig, 8); + memcpy(sig->data+8, seq_num, 8); + memcpy(sig->data+16, digest_final, 8); + memcpy(sig->data+24, confounder, 8); + + dump_data_pw("signature:", sig->data+ 0, 8); + dump_data_pw("seq_num :", sig->data+ 8, 8); + dump_data_pw("digest :", sig->data+16, 8); + dump_data_pw("confound :", sig->data+24, 8); + + return NT_STATUS_OK; +} + + +/* + sign a packet +*/ +NTSTATUS schannel_sign_packet(struct schannel_state *state, + const uchar *data, size_t length, + DATA_BLOB *sig) +{ + uchar digest_final[16]; + uchar seq_num[8]; + static const uchar netsec_sig[8] = NETSEC_SIGN_SIGNATURE; + + RSIVAL(seq_num, 0, state->seq_num); + SIVAL(seq_num, 4, state->initiator?0x80:0); + + schannel_digest(state->session_key, + netsec_sig, NULL, + data, length, digest_final); + + netsec_deal_with_seq_num(state, digest_final, seq_num); + + if (!state->signature.data) { + state->signature = data_blob_talloc(state->mem_ctx, NULL, 32); + if (!state->signature.data) { + return NT_STATUS_NO_MEMORY; + } + } + (*sig) = state->signature; + + memcpy(sig->data, netsec_sig, 8); + memcpy(sig->data+8, seq_num, 8); + memcpy(sig->data+16, digest_final, 8); + memset(sig->data+24, 0, 8); + + dump_data_pw("signature:", sig->data+ 0, 8); + dump_data_pw("seq_num :", sig->data+ 8, 8); + dump_data_pw("digest :", sig->data+16, 8); + dump_data_pw("confound :", sig->data+24, 8); + + return NT_STATUS_OK; +} + +/* + destroy an schannel context + */ +void schannel_end(struct schannel_state **state) +{ + talloc_destroy((*state)->mem_ctx); + (*state) = NULL; +} + +/* + create an schannel context state +*/ +NTSTATUS schannel_start(struct schannel_state **state, + uint8 session_key[16], + BOOL initiator) +{ + TALLOC_CTX *mem_ctx; + + mem_ctx = talloc_init("schannel_state"); + if (!mem_ctx) { + return NT_STATUS_NO_MEMORY; + } + + (*state) = talloc_p(mem_ctx, struct schannel_state); + if (!(*state)) { + talloc_destroy(mem_ctx); + return NT_STATUS_NO_MEMORY; + } + + (*state)->mem_ctx = mem_ctx; + memcpy((*state)->session_key, session_key, 16); + (*state)->initiator = initiator; + (*state)->signature = data_blob(NULL, 0); + (*state)->seq_num = 0; + + return NT_STATUS_OK; +} diff --git a/source4/libcli/auth/schannel.h b/source4/libcli/auth/schannel.h new file mode 100644 index 0000000000..7b710d7cb9 --- /dev/null +++ b/source4/libcli/auth/schannel.h @@ -0,0 +1,35 @@ +/* + Unix SMB/CIFS implementation. + + schannel library code + + Copyright (C) Andrew Tridgell 2004 + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. +*/ + +#include "includes.h" + +struct schannel_state { + TALLOC_CTX *mem_ctx; + uint8 session_key[16]; + uint32 seq_num; + BOOL initiator; + DATA_BLOB signature; +}; + +#define NETSEC_SIGN_SIGNATURE { 0x77, 0x00, 0xff, 0xff, 0xff, 0xff, 0x00, 0x00 } +#define NETSEC_SEAL_SIGNATURE { 0x77, 0x00, 0x7a, 0x00, 0xff, 0xff, 0x00, 0x00 } + |