PAM plugin with test

mysql-test/suite/plugins/r/pam.result

+install plugin pam soname 'auth_pam.so';
+create user test_pam identified via pam using 'mariadb_mtr';
+#
+# athentication is successful, challenge/pin are ok
+# note that current_user() differts from user()
+#
+Challenge input first.
+Enter: not very secret challenge
+Now, the magic number!
+PIN: ****
+select user(), current_user(), database();
+user()	current_user()	database()
+test_pam@localhost	pam_test@%	test
+#
+# athentication is unsuccessful
+#
+Challenge input first.
+Enter: not very secret challenge
+Now, the magic number!
+PIN: ****
+drop user test_pam;
+uninstall plugin pam;

mysql-test/suite/plugins/suite.pm

+package My::Suite::Plugins;
+
+@ISA = qw(My::Suite);
+
+$ENV{PAM_SETUP_FOR_MTR}=1 if -e '/etc/pam.d/mariadb_mtr';
+
+bless { };
+

mysql-test/suite/plugins/t/pam.test

+
+--source include/not_embedded.inc
+
+if (!$AUTH_PAM_SO) {
+  skip No pam auth plugin;
+}
+
+if (!$PAM_SETUP_FOR_MTR) {
+  skip No pam setup for mtr;
+}
+
+--replace_result .dll .so
+eval install plugin pam soname '$AUTH_PAM_SO';
+create user test_pam identified via pam using 'mariadb_mtr';
+
+let $plugindir=`SELECT @@global.plugin_dir`;
+
+--write_file $MYSQLTEST_VARDIR/tmp/pam_good.txt
+not very secret challenge
+9225
+select user(), current_user(), database();
+EOF
+
+--write_file $MYSQLTEST_VARDIR/tmp/pam_bad.txt
+not very secret challenge
+9224
+select user(), current_user(), database();
+EOF
+
+--echo #
+--echo # athentication is successful, challenge/pin are ok
+--echo # note that current_user() differts from user()
+--echo #
+--exec $MYSQL_TEST -u test_pam --plugin-dir=$plugindir < $MYSQLTEST_VARDIR/tmp/pam_good.txt
+
+--echo #
+--echo # athentication is unsuccessful
+--echo #
+--error 1
+--exec $MYSQL_TEST -u test_pam --plugin-dir=$plugindir < $MYSQLTEST_VARDIR/tmp/pam_bad.txt
+
+--remove_file $MYSQLTEST_VARDIR/tmp/pam_good.txt
+--remove_file $MYSQLTEST_VARDIR/tmp/pam_bad.txt
+drop user test_pam;
+uninstall plugin pam;
+

plugin/auth_pam/Makefile.am

+EXTRA_LTLIBRARIES      = auth_pam.la libauth_pam.la
+
+pkgplugindir=$(pkglibdir)/plugin
+AM_CPPFLAGS = -I$(top_srcdir)/include
+
+pkgplugin_LTLIBRARIES  = @plugin_auth_pam_shared_target@
+auth_pam_la_LDFLAGS    = -module -rpath $(pkgplugindir) -L$(top_builddir)/libservices -lmysqlservices -lpam
+auth_pam_la_CFLAGS     = -shared -DMYSQL_DYNAMIC_PLUGIN
+auth_pam_la_SOURCES    = auth_pam.c
+
+noinst_LTLIBRARIES     = @plugin_auth_pam_static_target@
+libauth_pam_la_LDFLAGS = -lpam
+libauth_pam_la_SOURCES = auth_pam.c
+
+EXTRA_DIST = plug.in
+

plugin/auth_pam/auth_pam.c

+#include <mysql/plugin_auth.h>
+#include <string.h>
+#include <security/pam_appl.h>
+#include <security/pam_modules.h>
+
+struct param {
+  unsigned char buf[10240], *ptr;
+  MYSQL_PLUGIN_VIO *vio;
+};
+
+static int conv(int n, const struct pam_message **msg,
+                struct pam_response **resp, void *data)
+{
+  struct param *param = (struct param *)data;
+  unsigned char *end = param->buf + sizeof(param->buf) - 1;
+  int i;
+
+  *resp = 0;
+
+  for (i = 0; i < n; i++)
+  {
+    /* if there's a message - append it to the buffer */
+    if (msg[i]->msg)
+    {
+      int len = strlen(msg[i]->msg);
+      if (len > end - param->ptr)
+        len = end - param->ptr;
+      if (len > 0)
+      {
+        memcpy(param->ptr, msg[i]->msg, len);
+        param->ptr+= len;
+        *(param->ptr)++ = '\n';
+      }
+    }
+    /* if the message style is *_PROMPT_*, meaning PAM asks a question,
+       send the accumulated text to the client, read the reply */
+    if (msg[i]->msg_style == PAM_PROMPT_ECHO_OFF ||
+        msg[i]->msg_style == PAM_PROMPT_ECHO_ON)
+    {
+      int pkt_len;
+      unsigned char *pkt;
+
+      /* allocate the response array.
+         freeing it is the responsibility of the caller */
+      if (*resp == 0)
+      {
+        *resp = calloc(sizeof(struct pam_response), n);
+        if (*resp == 0)
+          return PAM_BUF_ERR;
+      }
+
+      /* dialog plugin interprets the first byte of the packet
+         as the magic number.
+           2 means "read the input with the echo enabled"
+           4 means "password-like input, echo disabled"
+         C'est la vie. */
+      param->buf[0] = msg[i]->msg_style == PAM_PROMPT_ECHO_ON ? 2 : 4;
+      if (param->vio->write_packet(param->vio, param->buf, param->ptr - param->buf - 1))
+        return PAM_CONV_ERR;
+
+      pkt_len = param->vio->read_packet(param->vio, &pkt);
+      if (pkt_len < 0)
+        return PAM_CONV_ERR;
+      /* allocate and copy the reply to the response array */
+      (*resp)[i].resp = strndup((char*)pkt, pkt_len);
+      param->ptr = param->buf + 1;
+    }
+  }
+  return PAM_SUCCESS;
+}
+
+#define DO(X) if ((status = (X)) != PAM_SUCCESS) goto end
+
+static int pam_auth(MYSQL_PLUGIN_VIO *vio, MYSQL_SERVER_AUTH_INFO *info)
+{
+  pam_handle_t *pamh = NULL;
+  int status;
+  const char *new_username;
+  struct param param;
+  struct pam_conv c = { &conv, &param };
+
+  /*
+    get the service name, as specified in
+
+     CREATE USER ... IDENTIFIED WITH pam_auth AS  "service"
+  */
+  const char *service = info->auth_string && info->auth_string[0]
+                          ? info->auth_string : "mysql";
+
+  param.ptr = param.buf + 1;
+  param.vio = vio;
+
+  DO( pam_start(service, info->user_name, &c, &pamh) );
+  DO( pam_authenticate (pamh, 0) );
+  DO( pam_acct_mgmt(pamh, 0) );
+  DO( pam_get_item(pamh, PAM_USER, (const void**)&new_username) );
+
+  if (new_username && strcmp(new_username, info->user_name))
+    strncpy(info->authenticated_as, new_username,
+            sizeof(info->authenticated_as));
+
+end:
+  pam_end(pamh, status);
+  return status == PAM_SUCCESS ? CR_OK : CR_ERROR;
+}
+
+static struct st_mysql_auth pam_info =
+{
+  MYSQL_AUTHENTICATION_INTERFACE_VERSION,
+  "dialog",
+  pam_auth
+};
+
+maria_declare_plugin(pam)
+{
+  MYSQL_AUTHENTICATION_PLUGIN,
+  &pam_info,
+  "pam",
+  "Sergei Golubchik",
+  "PAM based authentication",
+  PLUGIN_LICENSE_GPL,
+  NULL,
+  NULL,
+  0x0100,
+  NULL,
+  NULL,
+  "1.0",
+  MariaDB_PLUGIN_MATURITY_BETA
+}
+maria_declare_plugin_end;

plugin/auth_pam/plug.in

+MYSQL_PLUGIN(auth_pam, [PAM Authentication Plugin], [PAM Authentication Plugin])
+MYSQL_PLUGIN_DYNAMIC(auth_pam, [auth_pam.la])
+
+AC_CHECK_HEADER([security/pam_appl.h],,[MYSQL_PLUGIN_WITHOUT(auth_pam)])

plugin/auth_pam/testing/pam_mariadb_mtr.c

+/*
+  Pam module to test pam authentication plugin. Used in pam.test.
+  Linux only.
+
+  Compile as
+  
+     gcc pam_mariadb_mtr.c -shared -lpam -fPIC -o pam_mariadb_mtr.so
+
+  Install as appropriate (for example, in /lib/security/).
+  Create /etc/pam.d/mariadb_mtr with
+=========================================================
+auth            required        pam_mariadb_mtr.so pam_test
+account         required        pam_mariadb_mtr.so
+=========================================================
+*/
+
+#include <stdlib.h>
+#include <string.h>
+#include <security/pam_modules.h>
+#include <security/pam_appl.h>
+
+#define N 3
+
+PAM_EXTERN int
+pam_sm_authenticate(pam_handle_t *pamh, int flags,
+    int argc, const char *argv[])
+{
+  struct pam_conv *conv;
+  struct pam_response *resp = 0;
+  int pam_err, retval = PAM_SYSTEM_ERR;
+  struct pam_message msg[N] = {
+    { PAM_TEXT_INFO, "Challenge input first." },
+    { PAM_PROMPT_ECHO_ON, "Enter:" },
+    { PAM_ERROR_MSG, "Now, the magic number!" }
+  };
+  const struct pam_message *msgp[N] = { msg, msg+1, msg+2 };
+  char *r1 = 0, *r2 = 0;
+
+  pam_err = pam_get_item(pamh, PAM_CONV, (const void **)&conv);
+  if (pam_err != PAM_SUCCESS)
+    goto ret;
+
+  pam_err = (*conv->conv)(N, msgp, &resp, conv->appdata_ptr);
+
+  if (pam_err != PAM_SUCCESS || !resp || !((r1= resp[1].resp)))
+    goto ret;
+
+  free(resp);
+
+  msg[0].msg_style = PAM_PROMPT_ECHO_OFF;
+  msg[0].msg = "PIN:";
+  pam_err = (*conv->conv)(1, msgp, &resp, conv->appdata_ptr);
+
+  if (pam_err != PAM_SUCCESS || !resp || !((r2= resp[0].resp)))
+    goto ret;
+
+  if (strlen(r1) == atoi(r2) % 100)
+    retval = PAM_SUCCESS;
+  else
+    retval = PAM_AUTH_ERR;
+
+  if (argc > 0 && argv[0])
+    pam_set_item(pamh, PAM_USER, argv[0]);
+
+ret:
+  free(resp);
+  free(r1);
+  free(r2);
+  return retval;
+}
+
+PAM_EXTERN int
+pam_sm_setcred(pam_handle_t *pamh, int flags,
+    int argc, const char *argv[])
+{
+
+    return PAM_SUCCESS;
+}
+
+PAM_EXTERN int
+pam_sm_acct_mgmt(pam_handle_t *pamh, int flags,
+    int argc, const char *argv[])
+{
+
+    return PAM_SUCCESS;
+}
+