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authorAndrew Bartlett <abartlet@samba.org>2009-03-16 15:20:28 +1100
committerAndrew Bartlett <abartlet@samba.org>2009-04-14 14:19:39 +1000
commit872cb0257c64f8c8682968565c3dfa608167a95d (patch)
tree08d4334094102993de88067ed84434d5f40c555c /libcli/drsuapi
parent927a8b330435b4c959ad851e32b83d97a6e3001b (diff)
downloadsamba-872cb0257c64f8c8682968565c3dfa608167a95d.tar.gz
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Move DRSUAPI per-attribute decryption into a common file
This file (contining metze's decryption routines) is now also be used by Samba3's DRSUAPI implementation Andrew Bartlett
Diffstat (limited to 'libcli/drsuapi')
-rw-r--r--libcli/drsuapi/config.mk8
-rw-r--r--libcli/drsuapi/drsuapi.h33
-rw-r--r--libcli/drsuapi/repl_decrypt.c188
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;
+}