Esa Korhonen 0996b9217a MXS-2544 Check roles in PAM authenticator
Also re-adds anonymous user support.
2019-07-16 11:36:11 +03:00

572 lines
19 KiB
C++

/*
* Copyright (c) 2016 MariaDB Corporation Ab
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
*
* Change Date: 2023-01-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2 or later of the General
* Public License.
*/
#include "pam_instance.hh"
#include <string>
#include <string.h>
#include <maxbase/format.hh>
#include <maxscale/jansson.hh>
#include <maxscale/paths.h>
#include <maxscale/secrets.h>
#include <maxscale/mysql_utils.hh>
using std::string;
using mxq::QueryResult;
/**
* Create an instance.
*
* @param options Listener options
* @return New client authenticator instance or NULL on error
*/
PamInstance* PamInstance::create(char** options)
{
// Name of the in-memory database.
// TODO: Once Centos6 is no longer needed and Sqlite version 3.7+ can be assumed,
// use a memory-only db with a URI filename (e.g. file:pam.db?mode=memory&cache=shared)
const string pam_db_fname = string(get_cachedir()) + "/pam_db.sqlite3";
if (sqlite3_threadsafe() == 0)
{
MXB_WARNING("SQLite3 was compiled with thread safety off. May cause corruption of "
"in-memory database.");
}
/* This handle may be used from multiple threads, set full mutex. */
int db_flags = SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE |
SQLITE_OPEN_SHAREDCACHE | SQLITE_OPEN_FULLMUTEX;
string sqlite_error;
PamInstance* instance = nullptr;
auto sqlite = SQLite::create(pam_db_fname, db_flags, &sqlite_error);
if (sqlite)
{
instance = new PamInstance(std::move(sqlite), pam_db_fname);
if (!instance->prepare_tables())
{
delete instance;
instance = nullptr;
}
}
else
{
MXB_ERROR("Could not create PAM authenticator: %s", sqlite_error.c_str());
}
return instance;
}
/**
* Constructor.
*
* @param dbhandle Database handle
* @param dbname Text-form name of @c dbhandle
* @param tablename Name of table where authentication data is saved
*/
PamInstance::PamInstance(SQLite::SSQLite dbhandle, const string& dbname)
: m_dbname(dbname)
, m_sqlite(std::move(dbhandle))
{
}
bool PamInstance::prepare_tables()
{
struct ColDef
{
enum class ColType {
BOOL,
TEXT,
};
string name;
ColType type;
};
using ColDefArray = std::vector<ColDef>;
using Type = ColDef::ColType;
/** Deletion statement for the in-memory table */
auto gen_drop_sql = [](const string& tblname) {
return "DROP TABLE IF EXISTS " + tblname + ";";
};
/** CREATE TABLE statement for the in-memory table */
auto gen_create_sql = [](const string& tblname, const ColDefArray& coldefs) {
string rval = "CREATE TABLE " + tblname + " (";
string sep;
for (const auto& coldef : coldefs)
{
string column_type;
switch (coldef.type)
{
case Type::BOOL:
column_type = "BOOLEAN";
break;
case Type::TEXT:
column_type = "TINYTEXT";
break;
}
rval += sep + coldef.name + " " + column_type;
sep = ",";
}
rval += "\n);";
return rval;
};
auto drop_recreate_table = [gen_drop_sql, gen_create_sql](SQLite* db, const string& tblname,
const ColDefArray& coldefs) {
bool rval = false;
string drop_query = gen_drop_sql(tblname);
string create_query = gen_create_sql(tblname, coldefs);
if (!db->exec(drop_query))
{
MXB_ERROR("Failed to delete sqlite3 table: %s", db->error());
}
else if (!db->exec(create_query))
{
MXB_ERROR("Failed to create sqlite3 table: %s", db->error());
}
else
{
rval = true;
}
return rval;
};
// Sqlite3 doesn't require datatypes in the create-statement but it's good to have for clarity.
const ColDefArray users_coldef = {{FIELD_USER, Type::TEXT},
{FIELD_HOST, Type::TEXT},
{FIELD_AUTHSTR, Type::TEXT},
{FIELD_DEF_ROLE, Type::TEXT},
{FIELD_ANYDB, Type::BOOL},
{FIELD_IS_ROLE, Type::BOOL},
{FIELD_HAS_PROXY, Type::BOOL}};
const ColDefArray dbs_coldef = {{FIELD_USER, Type::TEXT},
{FIELD_HOST, Type::TEXT},
{FIELD_DB, Type::TEXT}};
const ColDefArray roles_coldef = {{FIELD_USER, Type::TEXT},
{FIELD_HOST, Type::TEXT},
{FIELD_ROLE, Type::TEXT}};
bool rval = false;
auto sqlite = m_sqlite.get();
if (drop_recreate_table(sqlite, TABLE_USER, users_coldef)
&& drop_recreate_table(sqlite, TABLE_DB, dbs_coldef)
&& drop_recreate_table(sqlite, TABLE_ROLES_MAPPING, roles_coldef))
{
rval = true;
}
return rval;
}
/**
* @brief Add new PAM user entry to the internal user database
*
* @param user Username
* @param host Host
* @param db Database
* @param anydb Global access to databases
* @param pam_service The PAM service used
* @param proxy Is the user anonymous with a proxy grant
*/
void PamInstance::add_pam_user(const char* user, const char* host, const char* db, bool anydb,
const char* pam_service, bool proxy)
{
/**
* The insert query template which adds users to the pam_users table.
*
* Note that 'db' and 'pam_service' are strings that can be NULL and thus they have
* no quotes around them. The quotes for strings are added in this function.
*/
const string insert_sql_template =
"INSERT INTO " + TABLE_USER + " VALUES ('%s', '%s', %s, '%s', %s, '%s')";
/** Used for NULL value creation in the INSERT query */
const char NULL_TOKEN[] = "NULL";
string db_str;
if (db)
{
db_str = string("'") + db + "'";
}
else
{
db_str = NULL_TOKEN;
}
string service_str;
if (pam_service && *pam_service)
{
service_str = string("'") + pam_service + "'";
}
else
{
service_str = NULL_TOKEN;
}
size_t len = insert_sql_template.length() + strlen(user) + strlen(host) + db_str.length()
+ service_str.length() + 1;
char insert_sql[len + 1];
sprintf(insert_sql,
insert_sql_template.c_str(),
user, host,
db_str.c_str(), anydb ? "1" : "0",
service_str.c_str(),
proxy ? "1" : "0");
if (m_sqlite->exec(insert_sql))
{
if (proxy)
{
MXB_INFO("Added anonymous PAM user ''@'%s' with proxy grants using service %s.",
host, service_str.c_str());
}
else
{
MXB_INFO("Added normal PAM user '%s'@'%s' using service %s.", user, host, service_str.c_str());
}
}
else
{
MXB_ERROR("Failed to insert user: %s", m_sqlite->error());
}
}
/**
* @brief Delete old users from the database
*/
void PamInstance::delete_old_users()
{
/** Delete query used to clean up the database before loading new users */
const string delete_query = "DELETE FROM " + TABLE_USER + ";";
if (!m_sqlite->exec(delete_query))
{
MXB_ERROR("Failed to delete old users: %s", m_sqlite->error());
}
}
/**
* @brief Populates the internal user database by reading from one of the backend servers
*
* @param service The service the users should be read from
*
* @return MXS_AUTH_LOADUSERS_OK on success, MXS_AUTH_LOADUSERS_ERROR on error
*/
int PamInstance::load_users(SERVICE* service)
{
/** Query that gets all users that authenticate via the pam plugin */
string users_query, db_query, role_query;
auto prepare_queries = [&users_query, &db_query, &role_query](bool using_roles) {
string user_cols = "user, host, select_priv, insert_priv, update_priv, delete_priv, "
"authentication_string";
string filter = "plugin = 'pam'";
if (using_roles)
{
user_cols += ", default_role, is_role";
filter += " OR is_role = 'Y'"; // If using roles, accept them as well.
}
else
{
user_cols += ", '' AS default_role, 'N' AS is_role"; // keeps the number of columns constant
}
users_query = mxb::string_printf("SELECT %s FROM mysql.user WHERE %s;",
user_cols.c_str(), filter.c_str());
string join_filter = "b.plugin = 'pam'";
if (using_roles)
{
// Roles do not have plugins, yet may affect authentication.
join_filter += " OR b.is_role = 'Y'";
}
const string inner_join = "INNER JOIN mysql.user AS b ON (a.user = b.user AND a.host = b.host "
"AND (" + join_filter + "))";
// Read database grants for pam users and roles. This is combined with table grants.
db_query = "SELECT DISTINCT * FROM ("
// Select users/roles with general db-level privs ...
"(SELECT a.user, a.host, a.db FROM mysql.db AS a " + inner_join + ") "
"UNION "
// and combine with table privs counting as db-level privs.
"(SELECT a.user, a.host, a.db FROM mysql.tables_priv AS a " + inner_join + ")) AS c;";
if (using_roles)
{
role_query = "SELECT a.user, a.host, a.role FROM mysql.roles_mapping AS a "
+ inner_join + ";";
}
};
const char* user;
const char* pw_crypt;
serviceGetUser(service, &user, &pw_crypt);
int rval = MXS_AUTH_LOADUSERS_ERROR;
char* pw_clear = decrypt_password(pw_crypt);
if (pw_clear)
{
bool found_valid_server = false;
bool got_data = false;
for (auto sref = service->dbref; sref && !got_data; sref = sref->next)
{
SERVER* srv = sref->server;
if (srv->is_active && srv->is_usable())
{
bool using_roles = false;
auto version = srv->version();
// Default roles are in server version 10.1.1.
if (version.major > 10 || (version.major == 10 && (version.minor > 1
|| (version.minor == 1 && version.patch == 1))))
{
using_roles = true;
}
prepare_queries(using_roles);
found_valid_server = true;
MYSQL* mysql = mysql_init(NULL);
if (mxs_mysql_real_connect(mysql, srv, user, pw_clear))
{
string error_msg;
QResult users_res, dbs_res, roles_res;
// Perform the queries. All must succeed on the same backend.
// TODO: Think if it would be faster to do these queries concurrently.
if (((users_res = mxs::execute_query(mysql, users_query, &error_msg)) != nullptr)
&& ((dbs_res = mxs::execute_query(mysql, db_query, &error_msg)) != nullptr))
{
if (using_roles)
{
if ((roles_res = mxs::execute_query(mysql, role_query, &error_msg)) != nullptr)
{
got_data = true;
}
}
else
{
got_data = true;
}
}
if (got_data)
{
fill_user_arrays(std::move(users_res), std::move(dbs_res), std::move(roles_res));
fetch_anon_proxy_users(srv, mysql);
rval = MXS_AUTH_LOADUSERS_OK;
}
else
{
MXB_ERROR("Failed to query server '%s' for PAM users. %s",
srv->name(), error_msg.c_str());
}
}
mysql_close(mysql);
}
}
if (!found_valid_server)
{
MXB_ERROR("Service '%s' had no valid servers to query PAM users from.", service->name());
}
MXS_FREE(pw_clear);
}
return rval;
}
void PamInstance::fill_user_arrays(QResult user_res, QResult db_res, QResult roles_mapping_res)
{
m_sqlite->exec("BEGIN");
// Delete any previous data.
const char delete_fmt[] = "DELETE FROM %s;";
for (const auto& tbl : {TABLE_USER, TABLE_DB, TABLE_ROLES_MAPPING})
{
string query = mxb::string_printf(delete_fmt, tbl.c_str());
m_sqlite->exec(query);
}
// TODO: use prepared stmt:s
if (user_res)
{
auto get_bool_enum = [&user_res](int64_t col_ind) {
string val = user_res->get_string(col_ind);
return (val == "Y" || val == "y");
};
auto get_bool_any = [&get_bool_enum](int64_t col_ind_min, int64_t col_ind_max) {
bool rval = false;
for (auto i = col_ind_min; i <= col_ind_max && !rval; i++)
{
bool val = get_bool_enum(i);
if (val)
{
rval = true;
}
}
return rval;
};
// Input data order is: 0=user, 1=host, 2=select_priv, 3=insert_priv, 4=update_priv, 5=delete_priv,
// 6=authentication_string, 7=default_role, 8=is_role
// Output data order is: user, host, authentication_string, default_role, anydb, is_role, has_proxy.
// The proxy-part is sorted out later.
string insert_fmt = "INSERT INTO " + TABLE_USER + " VALUES ('%s', '%s', '%s', '%s', %i, %i, 0);";
while (user_res->next_row())
{
auto username = user_res->get_string(0);
auto host = user_res->get_string(1);
bool has_global_priv = get_bool_any(2, 5);
auto auth_string = user_res->get_string(6);
string default_role = user_res->get_string(7);
bool is_role = get_bool_enum(8);
m_sqlite->exec(mxb::string_printf(insert_fmt.c_str(), username.c_str(), host.c_str(),
auth_string.c_str(), default_role.c_str(), has_global_priv,
is_role));
}
}
if (db_res)
{
string insert_db_fmt = "INSERT INTO " + TABLE_DB + " VALUES ('%s', '%s', '%s');";
while (db_res->next_row())
{
auto username = db_res->get_string(0);
auto host = db_res->get_string(1);
auto datab = db_res->get_string(2);
m_sqlite->exec(mxb::string_printf(insert_db_fmt.c_str(),
username.c_str(), host.c_str(), datab.c_str()));
}
}
if (roles_mapping_res)
{
string insert_roles_fmt = "INSERT INTO " + TABLE_ROLES_MAPPING + " VALUES ('%s', '%s', '%s');";
while (roles_mapping_res->next_row())
{
auto username = roles_mapping_res->get_string(0);
auto host = roles_mapping_res->get_string(1);
auto role = roles_mapping_res->get_string(2);
m_sqlite->exec(mxb::string_printf(insert_roles_fmt.c_str(),
username.c_str(), host.c_str(), role.c_str()));
}
}
m_sqlite->exec("COMMIT");
}
void PamInstance::diagnostic(DCB* dcb)
{
json_t* array = diagnostic_json();
mxb_assert(json_is_array(array));
string result, separator;
size_t index;
json_t* value;
json_array_foreach(array, index, value)
{
// Only print user@host for the non-json version, as this should fit nicely on the console. Add the
// other fields if deemed useful.
const char* user = json_string_value(json_object_get(value, FIELD_USER.c_str()));
const char* host = json_string_value(json_object_get(value, FIELD_HOST.c_str()));
if (user && host)
{
result += separator + user + "@" + host;
separator = " ";
}
}
if (!result.empty())
{
dcb_printf(dcb, "%s", result.c_str());
}
json_decref(array);
}
static int diag_cb_json(json_t* data, int columns, char** row, char** field_names)
{
mxb_assert(columns == NUM_FIELDS);
json_t* obj = json_object();
for (int i = 0; i < columns; i++)
{
json_object_set_new(obj, field_names[i], json_string(row[i]));
}
json_array_append_new(data, obj);
return 0;
}
json_t* PamInstance::diagnostic_json()
{
json_t* rval = json_array();
string select = "SELECT * FROM " + TABLE_USER + ";";
if (!m_sqlite->exec(select, diag_cb_json, rval))
{
MXS_ERROR("Failed to print users: %s", m_sqlite->error());
}
return rval;
}
bool PamInstance::fetch_anon_proxy_users(SERVER* server, MYSQL* conn)
{
bool success = true;
const char anon_user_query[] = "SELECT host FROM mysql.user WHERE (user = '' AND plugin = 'pam');";
// Query for anonymous users used with group mappings
string error_msg;
QResult anon_res;
if ((anon_res = mxs::execute_query(conn, anon_user_query, &error_msg)) == nullptr)
{
MXS_ERROR("Failed to query server '%s' for anonymous PAM users. %s",
server->name(), error_msg.c_str());
success = false;
}
else
{
auto anon_rows = anon_res->get_row_count();
if (anon_rows > 0)
{
MXS_INFO("Found %lu anonymous PAM user(s). Checking them for proxy grants.", anon_rows);
}
while (anon_res->next_row())
{
string entry_host = anon_res->get_string(0);
string query = mxb::string_printf("SHOW GRANTS FOR ''@'%s';", entry_host.c_str());
// Check that the anon user has a proxy grant.
QResult grant_res;
if ((grant_res = mxs::execute_query(conn, query, &error_msg)) == nullptr)
{
MXS_ERROR("Failed to query server '%s' for grants of anonymous PAM user ''@'%s'. %s",
server->name(), entry_host.c_str(), error_msg.c_str());
success = false;
}
else
{
const char grant_proxy[] = "GRANT PROXY ON";
// The user may have multiple proxy grants. Just one is enough.
const string update_query_fmt = "UPDATE " + TABLE_USER + " SET " + FIELD_HAS_PROXY
+ " = 1 WHERE (" + FIELD_USER + " = '') AND (" + FIELD_HOST + " = '%s');";
while (grant_res->next_row())
{
string grant = grant_res->get_string(0);
if (grant.find(grant_proxy) != string::npos)
{
string update_query = mxb::string_printf(update_query_fmt.c_str(),
entry_host.c_str());
m_sqlite->exec(update_query);
break;
}
}
}
}
}
return success;
}