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Diffstat (limited to 'source3/smbd/seal.c')
| -rw-r--r-- | source3/smbd/seal.c | 726 |
1 files changed, 726 insertions, 0 deletions
diff --git a/source3/smbd/seal.c b/source3/smbd/seal.c new file mode 100644 index 0000000000..21fca73fea --- /dev/null +++ b/source3/smbd/seal.c @@ -0,0 +1,726 @@ +/* + 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. */ + if(CVAL(inbuf,0)) { + return false; + } + + status = get_enc_ctx_num(inbuf, &enc_num); + if (!NT_STATUS_IS_OK(status)) { + return false; + } + + 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 defined(HAVE_GSSAPI) && defined(HAVE_KRB5) + if (got_kerberos_mechanism && lp_use_kerberos_keytab() ) { + status = srv_enc_spnego_gss_negotiate(ppdata, p_data_size, secblob); + } else +#endif + { + 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); + + response = spnego_gen_auth_response(&auth_reply, status, OID_NTLMSSP); + 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; + + 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); +} |