diff options
Diffstat (limited to 'source4/dsdb/samdb/ldb_modules/audit_util.c')
| -rw-r--r-- | source4/dsdb/samdb/ldb_modules/audit_util.c | 697 |
1 files changed, 697 insertions, 0 deletions
diff --git a/source4/dsdb/samdb/ldb_modules/audit_util.c b/source4/dsdb/samdb/ldb_modules/audit_util.c new file mode 100644 index 0000000..f251025 --- /dev/null +++ b/source4/dsdb/samdb/ldb_modules/audit_util.c @@ -0,0 +1,697 @@ +/* + ldb database module utility library + + Copyright (C) Andrew Bartlett <abartlet@samba.org> 2018 + + 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/>. +*/ + +/* + * Common utility functions for SamDb audit logging. + * + */ + +#include "includes.h" +#include "ldb_module.h" +#include "lib/audit_logging/audit_logging.h" + +#include "dsdb/samdb/samdb.h" +#include "dsdb/samdb/ldb_modules/util.h" +#include "libcli/security/dom_sid.h" +#include "libcli/security/security_token.h" +#include "auth/common_auth.h" +#include "param/param.h" +#include "dsdb/samdb/ldb_modules/util.h" +#include "dsdb/samdb/ldb_modules/audit_util_proto.h" + +#define MAX_LENGTH 1024 + +#define min(a, b) (((a)>(b))?(b):(a)) + +/* + * List of attributes considered secret or confidential the values of these + * attributes should not be displayed in log messages. + */ +static const char * const secret_attributes[] = { + DSDB_SECRET_ATTRIBUTES, + NULL}; +/* + * List of attributes that contain a password, used to detect password changes + */ +static const char * const password_attributes[] = { + DSDB_PASSWORD_ATTRIBUTES, + NULL}; + +/* + * @brief Should the value of the specified value be redacted. + * + * The values of secret or password attributes should not be displayed. + * + * @param name The attributes name. + * + * @return True if the attribute should be redacted + */ +bool dsdb_audit_redact_attribute(const char * name) +{ + + if (ldb_attr_in_list(secret_attributes, name)) { + return true; + } + + if (ldb_attr_in_list(password_attributes, name)) { + return true; + } + + return false; +} + +/* + * @brief is the attribute a password attribute? + * + * Is the attribute a password attribute. + * + * @return True if the attribute is a "Password" attribute. + */ +bool dsdb_audit_is_password_attribute(const char * name) +{ + + bool is_password = ldb_attr_in_list(password_attributes, name); + return is_password; +} + +/* + * @brief Get the remote address from the ldb context. + * + * The remote address is stored in the ldb opaque value "remoteAddress" + * it is the responsibility of the higher level code to ensure that this + * value is set. + * + * @param ldb the ldb_context. + * + * @return the remote address if known, otherwise NULL. + */ +const struct tsocket_address *dsdb_audit_get_remote_address( + struct ldb_context *ldb) +{ + void *opaque_remote_address = NULL; + struct tsocket_address *remote_address; + + opaque_remote_address = ldb_get_opaque(ldb, + "remoteAddress"); + if (opaque_remote_address == NULL) { + return NULL; + } + + remote_address = talloc_get_type(opaque_remote_address, + struct tsocket_address); + return remote_address; +} + +/* + * @brief Get the actual user SID from ldb context. + * + * The actual user SID is stored in the ldb opaque value "networkSessionInfo" + * it is the responsibility of the higher level code to ensure that this + * value is set. + * + * @param ldb the ldb_context. + * + * @return the users actual sid. + */ +const struct dom_sid *dsdb_audit_get_actual_sid(struct ldb_context *ldb) +{ + void *opaque_session = NULL; + struct auth_session_info *session = NULL; + struct security_token *user_token = NULL; + + opaque_session = ldb_get_opaque(ldb, DSDB_NETWORK_SESSION_INFO); + if (opaque_session == NULL) { + return NULL; + } + + session = talloc_get_type(opaque_session, struct auth_session_info); + if (session == NULL) { + return NULL; + } + + user_token = session->security_token; + if (user_token == NULL) { + return NULL; + } + return &user_token->sids[0]; +} +/* + * @brief get the ldb error string. + * + * Get the ldb error string if set, otherwise get the generic error code + * for the status code. + * + * @param ldb the ldb_context. + * @param status the ldb_status code. + * + * @return a string describing the error. + */ +const char *dsdb_audit_get_ldb_error_string( + struct ldb_module *module, + int status) +{ + struct ldb_context *ldb = ldb_module_get_ctx(module); + const char *err_string = ldb_errstring(ldb); + + if (err_string == NULL) { + return ldb_strerror(status); + } + return err_string; +} + +/* + * @brief get the SID of the user performing the operation. + * + * Get the SID of the user performing the operation. + * + * @param module the ldb_module. + * + * @return the SID of the currently logged on user. + */ +const struct dom_sid *dsdb_audit_get_user_sid(const struct ldb_module *module) +{ + struct security_token *user_token = NULL; + + /* + * acl_user_token does not alter module so it's safe + * to discard the const. + */ + user_token = acl_user_token(discard_const(module)); + if (user_token == NULL) { + return NULL; + } + return &user_token->sids[0]; + +} + +/* + * @brief is operation being performed using the system session. + * + * Is the operation being performed using the system session. + * + * @param module the ldb_module. + * + * @return true if the operation is being performed using the system session. + */ +bool dsdb_audit_is_system_session(const struct ldb_module *module) +{ + struct security_token *user_token = NULL; + + /* + * acl_user_token does not alter module and security_token_is_system + * does not alter the security token so it's safe to discard the const. + */ + user_token = acl_user_token(discard_const(module)); + if (user_token == NULL) { + return false; + } + return security_token_is_system(user_token);; + +} + +/* + * @brief get the session identifier GUID + * + * Get the GUID that uniquely identifies the current authenticated session. + * + * @param module the ldb_module. + * + * @return the unique session GUID + */ +const struct GUID *dsdb_audit_get_unique_session_token( + const struct ldb_module *module) +{ + struct ldb_context *ldb = ldb_module_get_ctx(discard_const(module)); + struct auth_session_info *session_info + = (struct auth_session_info *)ldb_get_opaque( + ldb, + DSDB_SESSION_INFO); + if(!session_info) { + return NULL; + } + return &session_info->unique_session_token; +} + +/* + * @brief get the actual user session identifier + * + * Get the GUID that uniquely identifies the current authenticated session. + * This is the session of the connected user, as it may differ from the + * session the operation is being performed as, i.e. for operations performed + * under the system session. + * + * @param context the ldb_context. + * + * @return the unique session GUID + */ +const struct GUID *dsdb_audit_get_actual_unique_session_token( + struct ldb_context *ldb) +{ + struct auth_session_info *session_info + = (struct auth_session_info *)ldb_get_opaque( + ldb, + DSDB_NETWORK_SESSION_INFO); + if(!session_info) { + return NULL; + } + return &session_info->unique_session_token; +} + +/* + * @brief Get a printable string value for the remote host address. + * + * Get a printable string representation of the remote host, for display in the + * the audit logs. + * + * @param ldb the ldb context. + * @param mem_ctx the talloc memory context that will own the returned string. + * + * @return A string representation of the remote host address or "Unknown" + * + */ +char *dsdb_audit_get_remote_host(struct ldb_context *ldb, TALLOC_CTX *mem_ctx) +{ + const struct tsocket_address *remote_address; + char* remote_host = NULL; + + remote_address = dsdb_audit_get_remote_address(ldb); + if (remote_address == NULL) { + remote_host = talloc_asprintf(mem_ctx, "Unknown"); + return remote_host; + } + + remote_host = tsocket_address_string(remote_address, mem_ctx); + return remote_host; +} + +/* + * @brief get a printable representation of the primary DN. + * + * Get a printable representation of the primary DN. The primary DN is the + * DN of the object being added, deleted, modified or renamed. + * + * @param the ldb_request. + * + * @return a printable and linearized DN + */ +const char* dsdb_audit_get_primary_dn(const struct ldb_request *request) +{ + struct ldb_dn *dn = NULL; + switch (request->operation) { + case LDB_ADD: + if (request->op.add.message != NULL) { + dn = request->op.add.message->dn; + } + break; + case LDB_MODIFY: + if (request->op.mod.message != NULL) { + dn = request->op.mod.message->dn; + } + break; + case LDB_DELETE: + dn = request->op.del.dn; + break; + case LDB_RENAME: + dn = request->op.rename.olddn; + break; + default: + dn = NULL; + break; + } + if (dn == NULL) { + return NULL; + } + return ldb_dn_get_linearized(dn); +} + +/* + * @brief Get the ldb_message from a request. + * + * Get the ldb_message for the request, returns NULL is there is no + * associated ldb_message + * + * @param The request + * + * @return the message associated with this request, or NULL + */ +const struct ldb_message *dsdb_audit_get_message( + const struct ldb_request *request) +{ + switch (request->operation) { + case LDB_ADD: + return request->op.add.message; + case LDB_MODIFY: + return request->op.mod.message; + default: + return NULL; + } +} + +/* + * @brief get the secondary dn, i.e. the target dn for a rename. + * + * Get the secondary dn, i.e. the target for a rename. This is only applicable + * got a rename operation, for the non rename operations this function returns + * NULL. + * + * @param request the ldb_request. + * + * @return the secondary dn in a printable and linearized form. + */ +const char *dsdb_audit_get_secondary_dn(const struct ldb_request *request) +{ + switch (request->operation) { + case LDB_RENAME: + return ldb_dn_get_linearized(request->op.rename.newdn); + default: + return NULL; + } +} + +/* + * @brief Map the request operation to a description. + * + * Get a description of the operation for logging + * + * @param request the ldb_request + * + * @return a string describing the operation, or "Unknown" if the operation + * is not known. + */ +const char *dsdb_audit_get_operation_name(const struct ldb_request *request) +{ + switch (request->operation) { + case LDB_SEARCH: + return "Search"; + case LDB_ADD: + return "Add"; + case LDB_MODIFY: + return "Modify"; + case LDB_DELETE: + return "Delete"; + case LDB_RENAME: + return "Rename"; + case LDB_EXTENDED: + return "Extended"; + case LDB_REQ_REGISTER_CONTROL: + return "Register Control"; + case LDB_REQ_REGISTER_PARTITION: + return "Register Partition"; + default: + return "Unknown"; + } +} + +/* + * @brief get a description of a modify action for logging. + * + * Get a brief description of the modification action suitable for logging. + * + * @param flags the ldb_attributes flags. + * + * @return a brief description, or "unknown". + */ +const char *dsdb_audit_get_modification_action(unsigned int flags) +{ + switch (LDB_FLAG_MOD_TYPE(flags)) { + case LDB_FLAG_MOD_ADD: + return "add"; + case LDB_FLAG_MOD_DELETE: + return "delete"; + case LDB_FLAG_MOD_REPLACE: + return "replace"; + default: + return "unknown"; + } +} + +/* + * @brief Add an ldb_value to a json object array + * + * Convert the current ldb_value to a JSON object and append it to array. + * { + * "value":"xxxxxxxx", + * "base64":true + * "truncated":true + * } + * + * value is the JSON string representation of the ldb_val, + * will be null if the value is zero length. The value will be + * truncated if it is more than MAX_LENGTH bytes long. It will also + * be base64 encoded if it contains any non printable characters. + * + * base64 Indicates that the value is base64 encoded, will be absent if the + * value is not encoded. + * + * truncated Indicates that the length of the value exceeded MAX_LENGTH and was + * truncated. Note that vales are truncated and then base64 encoded. + * so an encoded value can be longer than MAX_LENGTH. + * + * @param array the JSON array to append the value to. + * @param lv the ldb_val to convert and append to the array. + * + */ +static int dsdb_audit_add_ldb_value(struct json_object *array, + const struct ldb_val lv) +{ + bool base64; + int len; + struct json_object value = json_empty_object; + int rc = 0; + + json_assert_is_array(array); + if (json_is_invalid(array)) { + return -1; + } + + if (lv.length == 0 || lv.data == NULL) { + rc = json_add_object(array, NULL, NULL); + if (rc != 0) { + goto failure; + } + return 0; + } + + base64 = ldb_should_b64_encode(NULL, &lv); + len = min(lv.length, MAX_LENGTH); + value = json_new_object(); + if (json_is_invalid(&value)) { + goto failure; + } + + if (lv.length > MAX_LENGTH) { + rc = json_add_bool(&value, "truncated", true); + if (rc != 0) { + goto failure; + } + } + if (base64) { + TALLOC_CTX *ctx = talloc_new(NULL); + char *encoded = ldb_base64_encode( + ctx, + (char*) lv.data, + len); + + if (ctx == NULL) { + goto failure; + } + + rc = json_add_bool(&value, "base64", true); + if (rc != 0) { + TALLOC_FREE(ctx); + goto failure; + } + rc = json_add_string(&value, "value", encoded); + if (rc != 0) { + TALLOC_FREE(ctx); + goto failure; + } + TALLOC_FREE(ctx); + } else { + rc = json_add_stringn(&value, "value", (char *)lv.data, len); + if (rc != 0) { + goto failure; + } + } + /* + * As array is a JSON array the element name is NULL + */ + rc = json_add_object(array, NULL, &value); + if (rc != 0) { + goto failure; + } + return 0; +failure: + /* + * In the event of a failure value will not have been added to array + * so it needs to be freed to prevent a leak. + */ + json_free(&value); + DBG_ERR("unable to add ldb value to JSON audit message"); + return -1; +} + +/* + * @brief Build a JSON object containing the attributes in an ldb_message. + * + * Build a JSON object containing all the attributes in an ldb_message. + * The attributes are keyed by attribute name, the values of "secret attributes" + * are supressed. + * + * { + * "password":{ + * "redacted":true, + * "action":"delete" + * }, + * "name":{ + * "values": [ + * { + * "value":"xxxxxxxx", + * "base64":true + * "truncated":true + * }, + * ], + * "action":"add", + * } + * } + * + * values is an array of json objects generated by add_ldb_value. + * redacted indicates that the attribute is secret. + * action is only set for modification operations. + * + * @param operation the ldb operation being performed + * @param message the ldb_message to process. + * + * @return A populated json object. + * + */ +struct json_object dsdb_audit_attributes_json( + enum ldb_request_type operation, + const struct ldb_message* message) +{ + + unsigned int i, j; + struct json_object attributes = json_new_object(); + + if (json_is_invalid(&attributes)) { + goto failure; + } + for (i=0;i<message->num_elements;i++) { + struct json_object actions = json_empty_object; + struct json_object attribute = json_empty_object; + struct json_object action = json_empty_object; + const char *name = message->elements[i].name; + int rc = 0; + + action = json_new_object(); + if (json_is_invalid(&action)) { + goto failure; + } + + /* + * If this is a modify operation tag the attribute with + * the modification action. + */ + if (operation == LDB_MODIFY) { + const char *act = NULL; + const int flags = message->elements[i].flags; + act = dsdb_audit_get_modification_action(flags); + rc = json_add_string(&action, "action", act); + if (rc != 0) { + json_free(&action); + goto failure; + } + } + if (operation == LDB_ADD) { + rc = json_add_string(&action, "action", "add"); + if (rc != 0) { + json_free(&action); + goto failure; + } + } + + /* + * If the attribute is a secret attribute, tag it as redacted + * and don't include the values + */ + if (dsdb_audit_redact_attribute(name)) { + rc = json_add_bool(&action, "redacted", true); + if (rc != 0) { + json_free(&action); + goto failure; + } + } else { + struct json_object values; + /* + * Add the values for the action + */ + values = json_new_array(); + if (json_is_invalid(&values)) { + json_free(&action); + goto failure; + } + + for (j=0;j<message->elements[i].num_values;j++) { + rc = dsdb_audit_add_ldb_value( + &values, message->elements[i].values[j]); + if (rc != 0) { + json_free(&values); + json_free(&action); + goto failure; + } + } + rc = json_add_object(&action, "values", &values); + if (rc != 0) { + json_free(&values); + json_free(&action); + goto failure; + } + } + attribute = json_get_object(&attributes, name); + if (json_is_invalid(&attribute)) { + json_free(&action); + goto failure; + } + actions = json_get_array(&attribute, "actions"); + if (json_is_invalid(&actions)) { + json_free(&action); + goto failure; + } + rc = json_add_object(&actions, NULL, &action); + if (rc != 0) { + json_free(&action); + goto failure; + } + rc = json_add_object(&attribute, "actions", &actions); + if (rc != 0) { + json_free(&actions); + goto failure; + } + rc = json_add_object(&attributes, name, &attribute); + if (rc != 0) { + json_free(&attribute); + goto failure; + } + } + return attributes; +failure: + json_free(&attributes); + DBG_ERR("Unable to create ldb attributes JSON audit message\n"); + return attributes; +} |