diff options
Diffstat (limited to 'libcli/drsuapi')
| -rw-r--r-- | libcli/drsuapi/config.mk | 8 | ||||
| -rw-r--r-- | libcli/drsuapi/drsuapi.h | 33 | ||||
| -rw-r--r-- | libcli/drsuapi/repl_decrypt.c | 188 |
3 files changed, 229 insertions, 0 deletions
diff --git a/libcli/drsuapi/config.mk b/libcli/drsuapi/config.mk new file mode 100644 index 0000000000..cb002ca3dc --- /dev/null +++ b/libcli/drsuapi/config.mk @@ -0,0 +1,8 @@ +[SUBSYSTEM::LIBCLI_DRSUAPI] +PUBLIC_DEPENDENCIES = \ + LIBCLI_AUTH + +LIBCLI_DRSUAPI_OBJ_FILES = $(addprefix $(libclicommonsrcdir)/drsuapi/, \ + repl_decrypt.o) + +PUBLIC_HEADERS += ../libcli/drsuapi/drsuapi.h diff --git a/libcli/drsuapi/drsuapi.h b/libcli/drsuapi/drsuapi.h new file mode 100644 index 0000000000..b95350779a --- /dev/null +++ b/libcli/drsuapi/drsuapi.h @@ -0,0 +1,33 @@ +/* + Unix SMB/CIFS mplementation. + Helper functions for applying replicated objects + + Copyright (C) Stefan Metzmacher <metze@samba.org> 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/>. + +*/ + +WERROR drsuapi_decrypt_attribute_value(TALLOC_CTX *mem_ctx, + const DATA_BLOB *gensec_skey, + bool rid_crypt, + uint32_t rid, + DATA_BLOB *in, + DATA_BLOB *out); + +WERROR drsuapi_decrypt_attribute(TALLOC_CTX *mem_ctx, + const DATA_BLOB *gensec_skey, + uint32_t rid, + struct drsuapi_DsReplicaAttribute *attr); + diff --git a/libcli/drsuapi/repl_decrypt.c b/libcli/drsuapi/repl_decrypt.c new file mode 100644 index 0000000000..9d7c1b6acf --- /dev/null +++ b/libcli/drsuapi/repl_decrypt.c @@ -0,0 +1,188 @@ +/* + Unix SMB/CIFS mplementation. + Helper functions for applying replicated objects + + Copyright (C) Stefan Metzmacher <metze@samba.org> 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" +#include "../lib/util/dlinklist.h" +#include "librpc/gen_ndr/ndr_misc.h" +#include "librpc/gen_ndr/ndr_drsuapi.h" +#include "librpc/gen_ndr/ndr_drsblobs.h" +#include "../lib/crypto/crypto.h" +#include "../libcli/drsuapi/drsuapi.h" +#include "libcli/auth/libcli_auth.h" + +WERROR drsuapi_decrypt_attribute_value(TALLOC_CTX *mem_ctx, + const DATA_BLOB *gensec_skey, + bool rid_crypt, + uint32_t rid, + DATA_BLOB *in, + DATA_BLOB *out) +{ + DATA_BLOB confounder; + DATA_BLOB enc_buffer; + + struct MD5Context md5; + uint8_t _enc_key[16]; + DATA_BLOB enc_key; + + DATA_BLOB dec_buffer; + + uint32_t crc32_given; + uint32_t crc32_calc; + DATA_BLOB checked_buffer; + + DATA_BLOB plain_buffer; + + /* + * users with rid == 0 should not exist + */ + if (rid_crypt && rid == 0) { + return WERR_DS_DRA_INVALID_PARAMETER; + } + + /* + * the first 16 bytes at the beginning are the confounder + * followed by the 4 byte crc32 checksum + */ + if (in->length < 20) { + return WERR_DS_DRA_INVALID_PARAMETER; + } + confounder = data_blob_const(in->data, 16); + enc_buffer = data_blob_const(in->data + 16, in->length - 16); + + /* + * build the encryption key md5 over the session key followed + * by the confounder + * + * here the gensec session key is used and + * not the dcerpc ncacn_ip_tcp "SystemLibraryDTC" key! + */ + enc_key = data_blob_const(_enc_key, sizeof(_enc_key)); + MD5Init(&md5); + MD5Update(&md5, gensec_skey->data, gensec_skey->length); + MD5Update(&md5, confounder.data, confounder.length); + MD5Final(enc_key.data, &md5); + + /* + * copy the encrypted buffer part and + * decrypt it using the created encryption key using arcfour + */ + dec_buffer = data_blob_const(enc_buffer.data, enc_buffer.length); + arcfour_crypt_blob(dec_buffer.data, dec_buffer.length, &enc_key); + + /* + * the first 4 byte are the crc32 checksum + * of the remaining bytes + */ + crc32_given = IVAL(dec_buffer.data, 0); + crc32_calc = crc32_calc_buffer(dec_buffer.data + 4 , dec_buffer.length - 4); + if (crc32_given != crc32_calc) { + return WERR_SEC_E_DECRYPT_FAILURE; + } + checked_buffer = data_blob_const(dec_buffer.data + 4, dec_buffer.length - 4); + + plain_buffer = data_blob_talloc(mem_ctx, checked_buffer.data, checked_buffer.length); + W_ERROR_HAVE_NO_MEMORY(plain_buffer.data); + + /* + * The following rid_crypt obfuscation isn't session specific + * and not really needed here, because we allways know the rid of the + * user account. + * + * some attributes with this 'additional encryption' include + * dBCSPwd, unicodePwd, ntPwdHistory, lmPwdHistory + * + * But for the rest of samba it's easier when we remove this static + * obfuscation here + */ + if (rid_crypt) { + uint32_t i, num_hashes; + + if ((checked_buffer.length % 16) != 0) { + return WERR_DS_DRA_INVALID_PARAMETER; + } + + num_hashes = plain_buffer.length / 16; + for (i = 0; i < num_hashes; i++) { + uint32_t offset = i * 16; + sam_rid_crypt(rid, checked_buffer.data + offset, plain_buffer.data + offset, 0); + } + } + + *out = plain_buffer; + return WERR_OK; +} + +WERROR drsuapi_decrypt_attribute(TALLOC_CTX *mem_ctx, + const DATA_BLOB *gensec_skey, + uint32_t rid, + struct drsuapi_DsReplicaAttribute *attr) +{ + WERROR status; + DATA_BLOB *enc_data; + DATA_BLOB plain_data; + bool rid_crypt = false; + + if (attr->value_ctr.num_values == 0) { + return WERR_OK; + } + + switch (attr->attid) { + case DRSUAPI_ATTRIBUTE_dBCSPwd: + case DRSUAPI_ATTRIBUTE_unicodePwd: + case DRSUAPI_ATTRIBUTE_ntPwdHistory: + case DRSUAPI_ATTRIBUTE_lmPwdHistory: + rid_crypt = true; + break; + case DRSUAPI_ATTRIBUTE_supplementalCredentials: + case DRSUAPI_ATTRIBUTE_priorValue: + case DRSUAPI_ATTRIBUTE_currentValue: + case DRSUAPI_ATTRIBUTE_trustAuthOutgoing: + case DRSUAPI_ATTRIBUTE_trustAuthIncoming: + case DRSUAPI_ATTRIBUTE_initialAuthOutgoing: + case DRSUAPI_ATTRIBUTE_initialAuthIncoming: + break; + default: + return WERR_OK; + } + + if (attr->value_ctr.num_values > 1) { + return WERR_DS_DRA_INVALID_PARAMETER; + } + + if (!attr->value_ctr.values[0].blob) { + return WERR_DS_DRA_INVALID_PARAMETER; + } + + enc_data = attr->value_ctr.values[0].blob; + + status = drsuapi_decrypt_attribute_value(mem_ctx, + gensec_skey, + rid_crypt, + rid, + enc_data, + &plain_data); + W_ERROR_NOT_OK_RETURN(status); + + talloc_free(attr->value_ctr.values[0].blob->data); + *attr->value_ctr.values[0].blob = plain_data; + + return WERR_OK; +} |