/* Unix SMB/CIFS implementation. SMB Transport encryption (sealing) code - server code. Copyright (C) Jeremy Allison 2007. 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 3 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, see <http://www.gnu.org/licenses/>. */ #include "includes.h" /****************************************************************************** Server side encryption. ******************************************************************************/ /****************************************************************************** Global server state. ******************************************************************************/ struct smb_srv_trans_enc_ctx { struct smb_trans_enc_state *es; AUTH_NTLMSSP_STATE *auth_ntlmssp_state; /* Must be kept in sync with pointer in ec->ntlmssp_state. */ }; static struct smb_srv_trans_enc_ctx *partial_srv_trans_enc_ctx; static struct smb_srv_trans_enc_ctx *srv_trans_enc_ctx; /****************************************************************************** Return global enc context - this must change if we ever do multiple contexts. ******************************************************************************/ uint16_t srv_enc_ctx(void) { return srv_trans_enc_ctx->es->enc_ctx_num; } /****************************************************************************** Is this an incoming encrypted packet ? ******************************************************************************/ bool is_encrypted_packet(const uint8_t *inbuf) { NTSTATUS status; uint16_t enc_num; /* Ignore non-session messages or non 0xFF'E' messages. */ if(CVAL(inbuf,0) || !(inbuf[4] == 0xFF && inbuf[5] == 'E')) { return false; } status = get_enc_ctx_num(inbuf, &enc_num); if (!NT_STATUS_IS_OK(status)) { return false; } /* Encrypted messages are 0xFF'E'<ctx> */ if (srv_trans_enc_ctx && enc_num == srv_enc_ctx()) { return true; } return false; } /****************************************************************************** Create an auth_ntlmssp_state and ensure pointer copy is correct. ******************************************************************************/ static NTSTATUS make_auth_ntlmssp(struct smb_srv_trans_enc_ctx *ec) { NTSTATUS status = auth_ntlmssp_start(&ec->auth_ntlmssp_state); if (!NT_STATUS_IS_OK(status)) { return nt_status_squash(status); } /* * We must remember to update the pointer copy for the common * functions after any auth_ntlmssp_start/auth_ntlmssp_end. */ ec->es->s.ntlmssp_state = ec->auth_ntlmssp_state->ntlmssp_state; return status; } /****************************************************************************** Destroy an auth_ntlmssp_state and ensure pointer copy is correct. ******************************************************************************/ static void destroy_auth_ntlmssp(struct smb_srv_trans_enc_ctx *ec) { /* * We must remember to update the pointer copy for the common * functions after any auth_ntlmssp_start/auth_ntlmssp_end. */ if (ec->auth_ntlmssp_state) { auth_ntlmssp_end(&ec->auth_ntlmssp_state); /* The auth_ntlmssp_end killed this already. */ ec->es->s.ntlmssp_state = NULL; } } #if defined(HAVE_GSSAPI) && defined(HAVE_KRB5) /****************************************************************************** Import a name. ******************************************************************************/ static NTSTATUS get_srv_gss_creds(const char *service, const char *name, gss_cred_usage_t cred_type, gss_cred_id_t *p_srv_cred) { OM_uint32 ret; OM_uint32 min; gss_name_t srv_name; gss_buffer_desc input_name; char *host_princ_s = NULL; NTSTATUS status = NT_STATUS_OK; gss_OID_desc nt_hostbased_service = {10, CONST_DISCARD(char *,"\x2a\x86\x48\x86\xf7\x12\x01\x02\x01\x04")}; asprintf(&host_princ_s, "%s@%s", service, name); if (host_princ_s == NULL) { return NT_STATUS_NO_MEMORY; } input_name.value = host_princ_s; input_name.length = strlen(host_princ_s) + 1; ret = gss_import_name(&min, &input_name, &nt_hostbased_service, &srv_name); DEBUG(10,("get_srv_gss_creds: imported name %s\n", host_princ_s )); if (ret != GSS_S_COMPLETE) { SAFE_FREE(host_princ_s); return map_nt_error_from_gss(ret, min); } /* * We're accessing the krb5.keytab file here. * ensure we have permissions to do so. */ become_root(); ret = gss_acquire_cred(&min, srv_name, GSS_C_INDEFINITE, GSS_C_NULL_OID_SET, cred_type, p_srv_cred, NULL, NULL); unbecome_root(); if (ret != GSS_S_COMPLETE) { ADS_STATUS adss = ADS_ERROR_GSS(ret, min); DEBUG(10,("get_srv_gss_creds: gss_acquire_cred failed with %s\n", ads_errstr(adss))); status = map_nt_error_from_gss(ret, min); } SAFE_FREE(host_princ_s); gss_release_name(&min, &srv_name); return status; } /****************************************************************************** Create a gss state. Try and get the cifs/server@realm principal first, then fall back to host/server@realm. ******************************************************************************/ static NTSTATUS make_auth_gss(struct smb_srv_trans_enc_ctx *ec) { NTSTATUS status; gss_cred_id_t srv_cred; fstring fqdn; name_to_fqdn(fqdn, global_myname()); strlower_m(fqdn); status = get_srv_gss_creds("cifs", fqdn, GSS_C_ACCEPT, &srv_cred); if (!NT_STATUS_IS_OK(status)) { status = get_srv_gss_creds("host", fqdn, GSS_C_ACCEPT, &srv_cred); if (!NT_STATUS_IS_OK(status)) { return nt_status_squash(status); } } ec->es->s.gss_state = SMB_MALLOC_P(struct smb_tran_enc_state_gss); if (!ec->es->s.gss_state) { OM_uint32 min; gss_release_cred(&min, &srv_cred); return NT_STATUS_NO_MEMORY; } ZERO_STRUCTP(ec->es->s.gss_state); ec->es->s.gss_state->creds = srv_cred; /* No context yet. */ ec->es->s.gss_state->gss_ctx = GSS_C_NO_CONTEXT; return NT_STATUS_OK; } #endif /****************************************************************************** Shutdown a server encryption context. ******************************************************************************/ static void srv_free_encryption_context(struct smb_srv_trans_enc_ctx **pp_ec) { struct smb_srv_trans_enc_ctx *ec = *pp_ec; if (!ec) { return; } if (ec->es) { switch (ec->es->smb_enc_type) { case SMB_TRANS_ENC_NTLM: destroy_auth_ntlmssp(ec); break; #if defined(HAVE_GSSAPI) && defined(HAVE_KRB5) case SMB_TRANS_ENC_GSS: break; #endif } common_free_encryption_state(&ec->es); } SAFE_FREE(ec); *pp_ec = NULL; } /****************************************************************************** Create a server encryption context. ******************************************************************************/ static NTSTATUS make_srv_encryption_context(enum smb_trans_enc_type smb_enc_type, struct smb_srv_trans_enc_ctx **pp_ec) { struct smb_srv_trans_enc_ctx *ec; *pp_ec = NULL; ec = SMB_MALLOC_P(struct smb_srv_trans_enc_ctx); if (!ec) { return NT_STATUS_NO_MEMORY; } ZERO_STRUCTP(partial_srv_trans_enc_ctx); ec->es = SMB_MALLOC_P(struct smb_trans_enc_state); if (!ec->es) { SAFE_FREE(ec); return NT_STATUS_NO_MEMORY; } ZERO_STRUCTP(ec->es); ec->es->smb_enc_type = smb_enc_type; switch (smb_enc_type) { case SMB_TRANS_ENC_NTLM: { NTSTATUS status = make_auth_ntlmssp(ec); if (!NT_STATUS_IS_OK(status)) { srv_free_encryption_context(&ec); return status; } } break; #if defined(HAVE_GSSAPI) && defined(HAVE_KRB5) case SMB_TRANS_ENC_GSS: /* Acquire our credentials by calling gss_acquire_cred here. */ { NTSTATUS status = make_auth_gss(ec); if (!NT_STATUS_IS_OK(status)) { srv_free_encryption_context(&ec); return status; } } break; #endif default: srv_free_encryption_context(&ec); return NT_STATUS_INVALID_PARAMETER; } *pp_ec = ec; return NT_STATUS_OK; } /****************************************************************************** Free an encryption-allocated buffer. ******************************************************************************/ void srv_free_enc_buffer(char *buf) { /* We know this is an smb buffer, and we * didn't malloc, only copy, for a keepalive, * so ignore non-session messages. */ if(CVAL(buf,0)) { return; } if (srv_trans_enc_ctx) { common_free_enc_buffer(srv_trans_enc_ctx->es, buf); } } /****************************************************************************** Decrypt an incoming buffer. ******************************************************************************/ NTSTATUS srv_decrypt_buffer(char *buf) { /* Ignore non-session messages. */ if(CVAL(buf,0)) { return NT_STATUS_OK; } if (srv_trans_enc_ctx) { return common_decrypt_buffer(srv_trans_enc_ctx->es, buf); } return NT_STATUS_OK; } /****************************************************************************** Encrypt an outgoing buffer. Return the encrypted pointer in buf_out. ******************************************************************************/ NTSTATUS srv_encrypt_buffer(char *buf, char **buf_out) { *buf_out = buf; /* Ignore non-session messages. */ if(CVAL(buf,0)) { return NT_STATUS_OK; } if (srv_trans_enc_ctx) { return common_encrypt_buffer(srv_trans_enc_ctx->es, buf, buf_out); } /* Not encrypting. */ return NT_STATUS_OK; } /****************************************************************************** Do the gss encryption negotiation. Parameters are in/out. Until success we do everything on the partial enc ctx. ******************************************************************************/ #if defined(HAVE_GSSAPI) && defined(HAVE_KRB5) static NTSTATUS srv_enc_spnego_gss_negotiate(unsigned char **ppdata, size_t *p_data_size, DATA_BLOB secblob) { OM_uint32 ret; OM_uint32 min; OM_uint32 flags = 0; gss_buffer_desc in_buf, out_buf; struct smb_tran_enc_state_gss *gss_state; DATA_BLOB auth_reply = data_blob_null; DATA_BLOB response = data_blob_null; NTSTATUS status; if (!partial_srv_trans_enc_ctx) { status = make_srv_encryption_context(SMB_TRANS_ENC_GSS, &partial_srv_trans_enc_ctx); if (!NT_STATUS_IS_OK(status)) { return status; } } gss_state = partial_srv_trans_enc_ctx->es->s.gss_state; in_buf.value = secblob.data; in_buf.length = secblob.length; out_buf.value = NULL; out_buf.length = 0; become_root(); ret = gss_accept_sec_context(&min, &gss_state->gss_ctx, gss_state->creds, &in_buf, GSS_C_NO_CHANNEL_BINDINGS, NULL, NULL, /* Ignore oids. */ &out_buf, /* To return. */ &flags, NULL, /* Ingore time. */ NULL); /* Ignore delegated creds. */ unbecome_root(); status = gss_err_to_ntstatus(ret, min); if (ret != GSS_S_COMPLETE && ret != GSS_S_CONTINUE_NEEDED) { return status; } /* Ensure we've got sign+seal available. */ if (ret == GSS_S_COMPLETE) { if ((flags & (GSS_C_INTEG_FLAG|GSS_C_CONF_FLAG|GSS_C_REPLAY_FLAG|GSS_C_SEQUENCE_FLAG)) != (GSS_C_INTEG_FLAG|GSS_C_CONF_FLAG|GSS_C_REPLAY_FLAG|GSS_C_SEQUENCE_FLAG)) { DEBUG(0,("srv_enc_spnego_gss_negotiate: quality of service not good enough " "for SMB sealing.\n")); gss_release_buffer(&min, &out_buf); return NT_STATUS_ACCESS_DENIED; } } auth_reply = data_blob(out_buf.value, out_buf.length); gss_release_buffer(&min, &out_buf); /* Wrap in SPNEGO. */ response = spnego_gen_auth_response(&auth_reply, status, OID_KERBEROS5); data_blob_free(&auth_reply); SAFE_FREE(*ppdata); *ppdata = response.data; *p_data_size = response.length; return status; } #endif /****************************************************************************** Do the NTLM SPNEGO (or raw) encryption negotiation. Parameters are in/out. Until success we do everything on the partial enc ctx. ******************************************************************************/ static NTSTATUS srv_enc_ntlm_negotiate(unsigned char **ppdata, size_t *p_data_size, DATA_BLOB secblob, bool spnego_wrap) { NTSTATUS status; DATA_BLOB chal = data_blob_null; DATA_BLOB response = data_blob_null; status = make_srv_encryption_context(SMB_TRANS_ENC_NTLM, &partial_srv_trans_enc_ctx); if (!NT_STATUS_IS_OK(status)) { return status; } status = auth_ntlmssp_update(partial_srv_trans_enc_ctx->auth_ntlmssp_state, secblob, &chal); /* status here should be NT_STATUS_MORE_PROCESSING_REQUIRED * for success ... */ if (spnego_wrap) { response = spnego_gen_auth_response(&chal, status, OID_NTLMSSP); data_blob_free(&chal); } else { /* Return the raw blob. */ response = chal; } SAFE_FREE(*ppdata); *ppdata = response.data; *p_data_size = response.length; return status; } /****************************************************************************** Do the SPNEGO encryption negotiation. Parameters are in/out. Based off code in smbd/sesssionsetup.c Until success we do everything on the partial enc ctx. ******************************************************************************/ static NTSTATUS srv_enc_spnego_negotiate(connection_struct *conn, unsigned char **ppdata, size_t *p_data_size, unsigned char **pparam, size_t *p_param_size) { NTSTATUS status; DATA_BLOB blob = data_blob_null; DATA_BLOB secblob = data_blob_null; bool got_kerberos_mechanism = false; blob = data_blob_const(*ppdata, *p_data_size); status = parse_spnego_mechanisms(blob, &secblob, &got_kerberos_mechanism); if (!NT_STATUS_IS_OK(status)) { return nt_status_squash(status); } /* We should have no partial context at this point. */ srv_free_encryption_context(&partial_srv_trans_enc_ctx); if (got_kerberos_mechanism) { #if defined(HAVE_GSSAPI) && defined(HAVE_KRB5) status = srv_enc_spnego_gss_negotiate(ppdata, p_data_size, secblob); #else /* Currently we don't SPNEGO negotiate * back to NTLMSSP as we do in sessionsetupX. We should... */ return NT_STATUS_LOGON_FAILURE; #endif } else { status = srv_enc_ntlm_negotiate(ppdata, p_data_size, secblob, true); } data_blob_free(&secblob); if (!NT_STATUS_EQUAL(status,NT_STATUS_MORE_PROCESSING_REQUIRED) && !NT_STATUS_IS_OK(status)) { srv_free_encryption_context(&partial_srv_trans_enc_ctx); return nt_status_squash(status); } if (NT_STATUS_IS_OK(status)) { /* Return the context we're using for this encryption state. */ if (!(*pparam = SMB_MALLOC_ARRAY(unsigned char, 2))) { return NT_STATUS_NO_MEMORY; } SSVAL(*pparam,0,partial_srv_trans_enc_ctx->es->enc_ctx_num); *p_param_size = 2; } return status; } /****************************************************************************** Complete a SPNEGO encryption negotiation. Parameters are in/out. We only get this for a NTLM auth second stage. ******************************************************************************/ static NTSTATUS srv_enc_spnego_ntlm_auth(connection_struct *conn, unsigned char **ppdata, size_t *p_data_size, unsigned char **pparam, size_t *p_param_size) { NTSTATUS status; DATA_BLOB blob = data_blob_null; DATA_BLOB auth = data_blob_null; DATA_BLOB auth_reply = data_blob_null; DATA_BLOB response = data_blob_null; struct smb_srv_trans_enc_ctx *ec = partial_srv_trans_enc_ctx; /* We must have a partial context here. */ if (!ec || !ec->es || ec->auth_ntlmssp_state == NULL || ec->es->smb_enc_type != SMB_TRANS_ENC_NTLM) { srv_free_encryption_context(&partial_srv_trans_enc_ctx); return NT_STATUS_INVALID_PARAMETER; } blob = data_blob_const(*ppdata, *p_data_size); if (!spnego_parse_auth(blob, &auth)) { srv_free_encryption_context(&partial_srv_trans_enc_ctx); return NT_STATUS_INVALID_PARAMETER; } status = auth_ntlmssp_update(ec->auth_ntlmssp_state, auth, &auth_reply); data_blob_free(&auth); /* From RFC4178. * * supportedMech * * This field SHALL only be present in the first reply from the * target. * So set mechOID to NULL here. */ response = spnego_gen_auth_response(&auth_reply, status, NULL); data_blob_free(&auth_reply); if (NT_STATUS_IS_OK(status)) { /* Return the context we're using for this encryption state. */ if (!(*pparam = SMB_MALLOC_ARRAY(unsigned char, 2))) { return NT_STATUS_NO_MEMORY; } SSVAL(*pparam,0,ec->es->enc_ctx_num); *p_param_size = 2; } SAFE_FREE(*ppdata); *ppdata = response.data; *p_data_size = response.length; return status; } /****************************************************************************** Raw NTLM encryption negotiation. Parameters are in/out. This function does both steps. ******************************************************************************/ static NTSTATUS srv_enc_raw_ntlm_auth(connection_struct *conn, unsigned char **ppdata, size_t *p_data_size, unsigned char **pparam, size_t *p_param_size) { NTSTATUS status; DATA_BLOB blob = data_blob_const(*ppdata, *p_data_size); DATA_BLOB response = data_blob_null; struct smb_srv_trans_enc_ctx *ec; if (!partial_srv_trans_enc_ctx) { /* This is the initial step. */ status = srv_enc_ntlm_negotiate(ppdata, p_data_size, blob, false); if (!NT_STATUS_EQUAL(status,NT_STATUS_MORE_PROCESSING_REQUIRED) && !NT_STATUS_IS_OK(status)) { srv_free_encryption_context(&partial_srv_trans_enc_ctx); return nt_status_squash(status); } return status; } ec = partial_srv_trans_enc_ctx; if (!ec || !ec->es || ec->auth_ntlmssp_state == NULL || ec->es->smb_enc_type != SMB_TRANS_ENC_NTLM) { srv_free_encryption_context(&partial_srv_trans_enc_ctx); return NT_STATUS_INVALID_PARAMETER; } /* Second step. */ status = auth_ntlmssp_update(partial_srv_trans_enc_ctx->auth_ntlmssp_state, blob, &response); if (NT_STATUS_IS_OK(status)) { /* Return the context we're using for this encryption state. */ if (!(*pparam = SMB_MALLOC_ARRAY(unsigned char, 2))) { return NT_STATUS_NO_MEMORY; } SSVAL(*pparam,0,ec->es->enc_ctx_num); *p_param_size = 2; } /* Return the raw blob. */ SAFE_FREE(*ppdata); *ppdata = response.data; *p_data_size = response.length; return status; } /****************************************************************************** Do the SPNEGO encryption negotiation. Parameters are in/out. ******************************************************************************/ NTSTATUS srv_request_encryption_setup(connection_struct *conn, unsigned char **ppdata, size_t *p_data_size, unsigned char **pparam, size_t *p_param_size) { unsigned char *pdata = *ppdata; SAFE_FREE(*pparam); *p_param_size = 0; if (*p_data_size < 1) { return NT_STATUS_INVALID_PARAMETER; } if (pdata[0] == ASN1_APPLICATION(0)) { /* its a negTokenTarg packet */ return srv_enc_spnego_negotiate(conn, ppdata, p_data_size, pparam, p_param_size); } if (pdata[0] == ASN1_CONTEXT(1)) { /* It's an auth packet */ return srv_enc_spnego_ntlm_auth(conn, ppdata, p_data_size, pparam, p_param_size); } /* Maybe it's a raw unwrapped auth ? */ if (*p_data_size < 7) { return NT_STATUS_INVALID_PARAMETER; } if (strncmp((char *)pdata, "NTLMSSP", 7) == 0) { return srv_enc_raw_ntlm_auth(conn, ppdata, p_data_size, pparam, p_param_size); } DEBUG(1,("srv_request_encryption_setup: Unknown packet\n")); return NT_STATUS_LOGON_FAILURE; } /****************************************************************************** Negotiation was successful - turn on server-side encryption. ******************************************************************************/ static NTSTATUS check_enc_good(struct smb_srv_trans_enc_ctx *ec) { if (!ec || !ec->es) { return NT_STATUS_LOGON_FAILURE; } if (ec->es->smb_enc_type == SMB_TRANS_ENC_NTLM) { if ((ec->es->s.ntlmssp_state->neg_flags & (NTLMSSP_NEGOTIATE_SIGN|NTLMSSP_NEGOTIATE_SEAL)) != (NTLMSSP_NEGOTIATE_SIGN|NTLMSSP_NEGOTIATE_SEAL)) { return NT_STATUS_INVALID_PARAMETER; } } /* Todo - check gssapi case. */ return NT_STATUS_OK; } /****************************************************************************** Negotiation was successful - turn on server-side encryption. ******************************************************************************/ NTSTATUS srv_encryption_start(connection_struct *conn) { NTSTATUS status; /* Check that we are really doing sign+seal. */ status = check_enc_good(partial_srv_trans_enc_ctx); if (!NT_STATUS_IS_OK(status)) { return status; } /* Throw away the context we're using currently (if any). */ srv_free_encryption_context(&srv_trans_enc_ctx); /* Steal the partial pointer. Deliberate shallow copy. */ srv_trans_enc_ctx = partial_srv_trans_enc_ctx; srv_trans_enc_ctx->es->enc_on = true; partial_srv_trans_enc_ctx = NULL; DEBUG(1,("srv_encryption_start: context negotiated\n")); return NT_STATUS_OK; } /****************************************************************************** Shutdown all server contexts. ******************************************************************************/ void server_encryption_shutdown(void) { srv_free_encryption_context(&partial_srv_trans_enc_ctx); srv_free_encryption_context(&srv_trans_enc_ctx); }