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/*
Copyright (c) 2011, 2020, MariaDB Corporation.
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; version 2 of the License.
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, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111-1301 USA */
#include <config_auth_pam.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <spawn.h>
#include <mysql/plugin_auth.h>
#include "auth_pam_tool.h"
#include <my_global.h>
#ifndef DBUG_OFF
static char pam_debug = 0;
#define PAM_DEBUG(X) do { if (pam_debug) { fprintf X; } } while(0)
#else
#define PAM_DEBUG(X) /* no-op */
#endif
static char winbind_hack = 0;
static char *opt_plugin_dir; /* To be dynamically linked. */
static const char *tool_name= "auth_pam_tool_dir/auth_pam_tool";
static const int tool_name_len= 31;
/*
sleep_limit is now 5 meaning up to 1 second sleep.
each step means 10 times longer sleep, so 6 would mean 10 seconds.
*/
static const unsigned int sleep_limit= 5;
static int pam_auth(MYSQL_PLUGIN_VIO *vio, MYSQL_SERVER_AUTH_INFO *info)
{
int p_to_c[2], c_to_p[2]; /* Parent-to-child and child-to-parent pipes. */
pid_t proc_id;
int result= CR_ERROR, pkt_len= 0;
unsigned char field, *pkt;
unsigned int n_sleep= 0;
useconds_t sleep_time= 100;
posix_spawn_file_actions_t file_actions;
char toolpath[FN_REFLEN];
size_t plugin_dir_len= strlen(opt_plugin_dir);
char *const argv[2]= {toolpath, 0};
int res;
PAM_DEBUG((stderr, "PAM: opening pipes.\n"));
if (pipe(p_to_c) < 0 || pipe(c_to_p) < 0)
{
my_printf_error(ENOEXEC, "pam: cannot create pipes (errno: %M)",
ME_ERROR_LOG_ONLY, errno);
return CR_ERROR;
}
if (plugin_dir_len + tool_name_len + 2 > sizeof(toolpath))
{
my_printf_error(ENOEXEC, "pam: too long path to <plugindir>/%s",
ME_ERROR_LOG_ONLY, tool_name);
return CR_ERROR;
}
memcpy(toolpath, opt_plugin_dir, plugin_dir_len);
if (plugin_dir_len && toolpath[plugin_dir_len-1] != FN_LIBCHAR)
toolpath[plugin_dir_len++]= FN_LIBCHAR;
memcpy(toolpath+plugin_dir_len, tool_name, tool_name_len+1);
PAM_DEBUG((stderr, "PAM: forking %s\n", toolpath));
res= posix_spawn_file_actions_init(&file_actions) ||
posix_spawn_file_actions_addclose(&file_actions, p_to_c[1]) ||
posix_spawn_file_actions_addclose(&file_actions, c_to_p[0]) ||
posix_spawn_file_actions_adddup2(&file_actions, p_to_c[0], 0) ||
posix_spawn_file_actions_adddup2(&file_actions, c_to_p[1], 1) ||
posix_spawn(&proc_id, toolpath, &file_actions, NULL, argv, NULL);
/* Parent process continues. */
posix_spawn_file_actions_destroy(&file_actions);
close(p_to_c[0]);
close(c_to_p[1]);
if (res)
{
my_printf_error(ENOEXEC, "pam: cannot exec %s (errno: %M)",
ME_ERROR_LOG_ONLY, toolpath, errno);
goto error_ret;
}
/* no user name yet ? read the client handshake packet with the user name */
if (info->user_name == 0)
{
if ((pkt_len= vio->read_packet(vio, &pkt)) < 0)
goto error_ret;
}
else
pkt= NULL;
PAM_DEBUG((stderr, "PAM: parent sends user data [%s], [%s].\n",
info->user_name, info->auth_string));
#ifndef DBUG_OFF
field= pam_debug ? 1 : 0;
#else
field= 0;
#endif
field|= winbind_hack ? 2 : 0;
if (write(p_to_c[1], &field, 1) != 1 ||
write_string(p_to_c[1], (const uchar *) info->user_name,
info->user_name_length) ||
write_string(p_to_c[1], (const uchar *) info->auth_string,
info->auth_string_length))
goto error_ret;
for (;;)
{
PAM_DEBUG((stderr, "PAM: listening to the sandbox.\n"));
if (read(c_to_p[0], &field, 1) < 1)
{
PAM_DEBUG((stderr, "PAM: read failed.\n"));
goto error_ret;
}
if (field == AP_EOF)
{
PAM_DEBUG((stderr, "PAM: auth OK returned.\n"));
break;
}
switch (field)
{
case AP_AUTHENTICATED_AS:
PAM_DEBUG((stderr, "PAM: reading authenticated_as string.\n"));
if (read_string(c_to_p[0], info->authenticated_as,
sizeof(info->authenticated_as) - 1) < 0)
goto error_ret;
break;
case AP_CONV:
{
unsigned char buf[10240];
int buf_len;
PAM_DEBUG((stderr, "PAM: getting CONV string.\n"));
if ((buf_len= read_string(c_to_p[0], (char *) buf, sizeof(buf))) < 0)
goto error_ret;
if (!pkt || !*pkt || (buf[0] >> 1) != 2)
{
PAM_DEBUG((stderr, "PAM: sending CONV string.\n"));
if (vio->write_packet(vio, buf, buf_len))
goto error_ret;
PAM_DEBUG((stderr, "PAM: reading CONV answer.\n"));
if ((pkt_len= vio->read_packet(vio, &pkt)) < 0)
goto error_ret;
}
PAM_DEBUG((stderr, "PAM: answering CONV.\n"));
if (write_string(p_to_c[1], pkt, pkt_len))
goto error_ret;
pkt= NULL;
}
break;
default:
PAM_DEBUG((stderr, "PAM: unknown sandbox field.\n"));
goto error_ret;
}
}
result= CR_OK;
error_ret:
close(p_to_c[1]);
close(c_to_p[0]);
while (waitpid(proc_id, NULL, WNOHANG) != (int) proc_id)
{
if (n_sleep++ == sleep_limit)
{
/*
The auth_pam_tool application doesn't terminate.
Means something wrong happened there like pam_xxx.so hanged.
*/
kill(proc_id, SIGKILL);
sleep_time= 1000000; /* 1 second wait should be enough. */
PAM_DEBUG((stderr, "PAM: auth_pam_tool doesn't terminate,"
" have to kill it.\n"));
}
else if (n_sleep > sleep_limit)
break;
usleep(sleep_time);
sleep_time*= 10;
}
PAM_DEBUG((stderr, "PAM: auth result %d.\n", result));
return result;
}
#include "auth_pam_common.c"
static int init(void *p __attribute__((unused)))
{
if (use_cleartext_plugin)
info.client_auth_plugin= "mysql_clear_password";
if (!(opt_plugin_dir= dlsym(RTLD_DEFAULT, "opt_plugin_dir")))
return 1;
return 0;
}
maria_declare_plugin(pam)
{
MYSQL_AUTHENTICATION_PLUGIN,
&info,
"pam",
"MariaDB Corp",
"PAM based authentication",
PLUGIN_LICENSE_GPL,
init,
NULL,
0x0200,
NULL,
vars,
"2.0",
MariaDB_PLUGIN_MATURITY_STABLE
}
maria_declare_plugin_end;
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