diff options
Diffstat (limited to 'openvpn/plugin/auth-pam/auth-pam.c')
-rw-r--r-- | openvpn/plugin/auth-pam/auth-pam.c | 755 |
1 files changed, 0 insertions, 755 deletions
diff --git a/openvpn/plugin/auth-pam/auth-pam.c b/openvpn/plugin/auth-pam/auth-pam.c deleted file mode 100644 index 5047b34..0000000 --- a/openvpn/plugin/auth-pam/auth-pam.c +++ /dev/null @@ -1,755 +0,0 @@ -/* - * OpenVPN -- An application to securely tunnel IP networks - * over a single TCP/UDP port, with support for SSL/TLS-based - * session authentication and key exchange, - * packet encryption, packet authentication, and - * packet compression. - * - * Copyright (C) 2002-2005 OpenVPN Solutions LLC <info@openvpn.net> - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 - * as published by the Free Software Foundation. - * - * 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 (see the file COPYING included with this - * distribution); if not, write to the Free Software Foundation, Inc., - * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA - */ - -/* - * OpenVPN plugin module to do PAM authentication using a split - * privilege model. - */ - -#if DLOPEN_PAM -#include <dlfcn.h> -#include "pamdl.h" -#else -#include <security/pam_appl.h> -#endif - -#include <stdio.h> -#include <string.h> -#include <ctype.h> -#include <unistd.h> -#include <stdlib.h> -#include <sys/types.h> -#include <sys/socket.h> -#include <sys/wait.h> -#include <fcntl.h> -#include <signal.h> -#include <syslog.h> - -#include "openvpn-plugin.h" - -#define DEBUG(verb) ((verb) >= 7) - -/* Command codes for foreground -> background communication */ -#define COMMAND_VERIFY 0 -#define COMMAND_EXIT 1 - -/* Response codes for background -> foreground communication */ -#define RESPONSE_INIT_SUCCEEDED 10 -#define RESPONSE_INIT_FAILED 11 -#define RESPONSE_VERIFY_SUCCEEDED 12 -#define RESPONSE_VERIFY_FAILED 13 - -/* - * Plugin state, used by foreground - */ -struct auth_pam_context -{ - /* Foreground's socket to background process */ - int foreground_fd; - - /* Process ID of background process */ - pid_t background_pid; - - /* Verbosity level of OpenVPN */ - int verb; -}; - -/* - * Name/Value pairs for conversation function. - * Special Values: - * - * "USERNAME" -- substitute client-supplied username - * "PASSWORD" -- substitute client-specified password - */ - -#define N_NAME_VALUE 16 - -struct name_value { - const char *name; - const char *value; -}; - -struct name_value_list { - int len; - struct name_value data[N_NAME_VALUE]; -}; - -/* - * Used to pass the username/password - * to the PAM conversation function. - */ -struct user_pass { - int verb; - - char username[128]; - char password[128]; - - const struct name_value_list *name_value_list; -}; - -/* Background process function */ -static void pam_server (int fd, const char *service, int verb, const struct name_value_list *name_value_list); - -/* - * Given an environmental variable name, search - * the envp array for its value, returning it - * if found or NULL otherwise. - */ -static const char * -get_env (const char *name, const char *envp[]) -{ - if (envp) - { - int i; - const int namelen = strlen (name); - for (i = 0; envp[i]; ++i) - { - if (!strncmp (envp[i], name, namelen)) - { - const char *cp = envp[i] + namelen; - if (*cp == '=') - return cp + 1; - } - } - } - return NULL; -} - -/* - * Return the length of a string array - */ -static int -string_array_len (const char *array[]) -{ - int i = 0; - if (array) - { - while (array[i]) - ++i; - } - return i; -} - -/* - * Socket read/write functions. - */ - -static int -recv_control (int fd) -{ - unsigned char c; - const ssize_t size = read (fd, &c, sizeof (c)); - if (size == sizeof (c)) - return c; - else - { - /*fprintf (stderr, "AUTH-PAM: DEBUG recv_control.read=%d\n", (int)size);*/ - return -1; - } -} - -static int -send_control (int fd, int code) -{ - unsigned char c = (unsigned char) code; - const ssize_t size = write (fd, &c, sizeof (c)); - if (size == sizeof (c)) - return (int) size; - else - return -1; -} - -static int -recv_string (int fd, char *buffer, int len) -{ - if (len > 0) - { - ssize_t size; - memset (buffer, 0, len); - size = read (fd, buffer, len); - buffer[len-1] = 0; - if (size >= 1) - return (int)size; - } - return -1; -} - -static int -send_string (int fd, const char *string) -{ - const int len = strlen (string) + 1; - const ssize_t size = write (fd, string, len); - if (size == len) - return (int) size; - else - return -1; -} - -/* - * Daemonize if "daemon" env var is true. - * Preserve stderr across daemonization if - * "daemon_log_redirect" env var is true. - */ -static void -daemonize (const char *envp[]) -{ - const char *daemon_string = get_env ("daemon", envp); - if (daemon_string && daemon_string[0] == '1') - { - const char *log_redirect = get_env ("daemon_log_redirect", envp); - int fd = -1; - if (log_redirect && log_redirect[0] == '1') - fd = dup (2); - if (daemon (0, 0) < 0) - { - fprintf (stderr, "AUTH-PAM: daemonization failed\n"); - } - else if (fd >= 3) - { - dup2 (fd, 2); - close (fd); - } - } -} - -/* - * Close most of parent's fds. - * Keep stdin/stdout/stderr, plus one - * other fd which is presumed to be - * our pipe back to parent. - * Admittedly, a bit of a kludge, - * but posix doesn't give us a kind - * of FD_CLOEXEC which will stop - * fds from crossing a fork(). - */ -static void -close_fds_except (int keep) -{ - int i; - closelog (); - for (i = 3; i <= 100; ++i) - { - if (i != keep) - close (i); - } -} - -/* - * Usually we ignore signals, because our parent will - * deal with them. - */ -static void -set_signals (void) -{ - signal (SIGTERM, SIG_DFL); - - signal (SIGINT, SIG_IGN); - signal (SIGHUP, SIG_IGN); - signal (SIGUSR1, SIG_IGN); - signal (SIGUSR2, SIG_IGN); - signal (SIGPIPE, SIG_IGN); -} - -/* - * Return 1 if query matches match. - */ -static int -name_value_match (const char *query, const char *match) -{ - while (!isalnum (*query)) - { - if (*query == '\0') - return 0; - ++query; - } - return strncasecmp (match, query, strlen (match)) == 0; -} - -OPENVPN_EXPORT openvpn_plugin_handle_t -openvpn_plugin_open_v1 (unsigned int *type_mask, const char *argv[], const char *envp[]) -{ - pid_t pid; - int fd[2]; - - struct auth_pam_context *context; - struct name_value_list name_value_list; - - const int base_parms = 2; - - /* - * Allocate our context - */ - context = (struct auth_pam_context *) calloc (1, sizeof (struct auth_pam_context)); - context->foreground_fd = -1; - - /* - * Intercept the --auth-user-pass-verify callback. - */ - *type_mask = OPENVPN_PLUGIN_MASK (OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY); - - /* - * Make sure we have two string arguments: the first is the .so name, - * the second is the PAM service type. - */ - if (string_array_len (argv) < base_parms) - { - fprintf (stderr, "AUTH-PAM: need PAM service parameter\n"); - goto error; - } - - /* - * See if we have optional name/value pairs to match against - * PAM module queried fields in the conversation function. - */ - name_value_list.len = 0; - if (string_array_len (argv) > base_parms) - { - const int nv_len = string_array_len (argv) - base_parms; - int i; - - if ((nv_len & 1) == 1 || (nv_len / 2) > N_NAME_VALUE) - { - fprintf (stderr, "AUTH-PAM: bad name/value list length\n"); - goto error; - } - - name_value_list.len = nv_len / 2; - for (i = 0; i < name_value_list.len; ++i) - { - const int base = base_parms + i * 2; - name_value_list.data[i].name = argv[base]; - name_value_list.data[i].value = argv[base+1]; - } - } - - /* - * Get verbosity level from environment - */ - { - const char *verb_string = get_env ("verb", envp); - if (verb_string) - context->verb = atoi (verb_string); - } - - /* - * Make a socket for foreground and background processes - * to communicate. - */ - if (socketpair (PF_UNIX, SOCK_DGRAM, 0, fd) == -1) - { - fprintf (stderr, "AUTH-PAM: socketpair call failed\n"); - goto error; - } - - /* - * Fork off the privileged process. It will remain privileged - * even after the foreground process drops its privileges. - */ - pid = fork (); - - if (pid) - { - int status; - - /* - * Foreground Process - */ - - context->background_pid = pid; - - /* close our copy of child's socket */ - close (fd[1]); - - /* don't let future subprocesses inherit child socket */ - if (fcntl (fd[0], F_SETFD, FD_CLOEXEC) < 0) - fprintf (stderr, "AUTH-PAM: Set FD_CLOEXEC flag on socket file descriptor failed\n"); - - /* wait for background child process to initialize */ - status = recv_control (fd[0]); - if (status == RESPONSE_INIT_SUCCEEDED) - { - context->foreground_fd = fd[0]; - return (openvpn_plugin_handle_t) context; - } - } - else - { - /* - * Background Process - */ - - /* close all parent fds except our socket back to parent */ - close_fds_except (fd[1]); - - /* Ignore most signals (the parent will receive them) */ - set_signals (); - - /* Daemonize if --daemon option is set. */ - daemonize (envp); - - /* execute the event loop */ - pam_server (fd[1], argv[1], context->verb, &name_value_list); - - close (fd[1]); - - exit (0); - return 0; /* NOTREACHED */ - } - - error: - if (context) - free (context); - return NULL; -} - -OPENVPN_EXPORT int -openvpn_plugin_func_v1 (openvpn_plugin_handle_t handle, const int type, const char *argv[], const char *envp[]) -{ - struct auth_pam_context *context = (struct auth_pam_context *) handle; - - if (type == OPENVPN_PLUGIN_AUTH_USER_PASS_VERIFY && context->foreground_fd >= 0) - { - /* get username/password from envp string array */ - const char *username = get_env ("username", envp); - const char *password = get_env ("password", envp); - - if (username && strlen (username) > 0 && password) - { - if (send_control (context->foreground_fd, COMMAND_VERIFY) == -1 - || send_string (context->foreground_fd, username) == -1 - || send_string (context->foreground_fd, password) == -1) - { - fprintf (stderr, "AUTH-PAM: Error sending auth info to background process\n"); - } - else - { - const int status = recv_control (context->foreground_fd); - if (status == RESPONSE_VERIFY_SUCCEEDED) - return OPENVPN_PLUGIN_FUNC_SUCCESS; - if (status == -1) - fprintf (stderr, "AUTH-PAM: Error receiving auth confirmation from background process\n"); - } - } - } - return OPENVPN_PLUGIN_FUNC_ERROR; -} - -OPENVPN_EXPORT void -openvpn_plugin_close_v1 (openvpn_plugin_handle_t handle) -{ - struct auth_pam_context *context = (struct auth_pam_context *) handle; - - if (DEBUG (context->verb)) - fprintf (stderr, "AUTH-PAM: close\n"); - - if (context->foreground_fd >= 0) - { - /* tell background process to exit */ - if (send_control (context->foreground_fd, COMMAND_EXIT) == -1) - fprintf (stderr, "AUTH-PAM: Error signaling background process to exit\n"); - - /* wait for background process to exit */ - if (context->background_pid > 0) - waitpid (context->background_pid, NULL, 0); - - close (context->foreground_fd); - context->foreground_fd = -1; - } - - free (context); -} - -OPENVPN_EXPORT void -openvpn_plugin_abort_v1 (openvpn_plugin_handle_t handle) -{ - struct auth_pam_context *context = (struct auth_pam_context *) handle; - - /* tell background process to exit */ - if (context->foreground_fd >= 0) - { - send_control (context->foreground_fd, COMMAND_EXIT); - close (context->foreground_fd); - context->foreground_fd = -1; - } -} - -/* - * PAM conversation function - */ -static int -my_conv (int n, const struct pam_message **msg_array, - struct pam_response **response_array, void *appdata_ptr) -{ - const struct user_pass *up = ( const struct user_pass *) appdata_ptr; - struct pam_response *aresp; - int i; - int ret = PAM_SUCCESS; - - *response_array = NULL; - - if (n <= 0 || n > PAM_MAX_NUM_MSG) - return (PAM_CONV_ERR); - if ((aresp = calloc (n, sizeof *aresp)) == NULL) - return (PAM_BUF_ERR); - - /* loop through each PAM-module query */ - for (i = 0; i < n; ++i) - { - const struct pam_message *msg = msg_array[i]; - aresp[i].resp_retcode = 0; - aresp[i].resp = NULL; - - if (DEBUG (up->verb)) - { - fprintf (stderr, "AUTH-PAM: BACKGROUND: my_conv[%d] query='%s' style=%d\n", - i, - msg->msg ? msg->msg : "NULL", - msg->msg_style); - } - - if (up->name_value_list && up->name_value_list->len > 0) - { - /* use name/value list match method */ - const struct name_value_list *list = up->name_value_list; - int j; - - /* loop through name/value pairs */ - for (j = 0; j < list->len; ++j) - { - const char *match_name = list->data[j].name; - const char *match_value = list->data[j].value; - - if (name_value_match (msg->msg, match_name)) - { - /* found name/value match */ - const char *return_value = NULL; - - if (DEBUG (up->verb)) - fprintf (stderr, "AUTH-PAM: BACKGROUND: name match found, query/match-string ['%s', '%s'] = '%s'\n", - msg->msg, - match_name, - match_value); - - if (!strcmp (match_value, "USERNAME")) - return_value = up->username; - else if (!strcmp (match_value, "PASSWORD")) - return_value = up->password; - else - return_value = match_value; - - aresp[i].resp = strdup (return_value); - if (aresp[i].resp == NULL) - ret = PAM_CONV_ERR; - break; - } - } - - if (j == list->len) - ret = PAM_CONV_ERR; - } - else - { - /* use PAM_PROMPT_ECHO_x hints */ - switch (msg->msg_style) - { - case PAM_PROMPT_ECHO_OFF: - aresp[i].resp = strdup (up->password); - if (aresp[i].resp == NULL) - ret = PAM_CONV_ERR; - break; - - case PAM_PROMPT_ECHO_ON: - aresp[i].resp = strdup (up->username); - if (aresp[i].resp == NULL) - ret = PAM_CONV_ERR; - break; - - case PAM_ERROR_MSG: - case PAM_TEXT_INFO: - break; - - default: - ret = PAM_CONV_ERR; - break; - } - } - } - - if (ret == PAM_SUCCESS) - *response_array = aresp; - return ret; -} - -/* - * Return 1 if authenticated and 0 if failed. - * Called once for every username/password - * to be authenticated. - */ -static int -pam_auth (const char *service, const struct user_pass *up) -{ - struct pam_conv conv; - pam_handle_t *pamh = NULL; - int status = PAM_SUCCESS; - int ret = 0; - const int name_value_list_provided = (up->name_value_list && up->name_value_list->len > 0); - - /* Initialize PAM */ - conv.conv = my_conv; - conv.appdata_ptr = (void *)up; - status = pam_start (service, name_value_list_provided ? NULL : up->username, &conv, &pamh); - if (status == PAM_SUCCESS) - { - /* Call PAM to verify username/password */ - status = pam_authenticate(pamh, 0); - if (status == PAM_SUCCESS) - status = pam_acct_mgmt (pamh, 0); - if (status == PAM_SUCCESS) - ret = 1; - - /* Output error message if failed */ - if (!ret) - { - fprintf (stderr, "AUTH-PAM: BACKGROUND: user '%s' failed to authenticate: %s\n", - up->username, - pam_strerror (pamh, status)); - } - - /* Close PAM */ - pam_end (pamh, status); - } - - return ret; -} - -/* - * Background process -- runs with privilege. - */ -static void -pam_server (int fd, const char *service, int verb, const struct name_value_list *name_value_list) -{ - struct user_pass up; - int command; -#if DLOPEN_PAM - static const char pam_so[] = "libpam.so"; -#endif - - /* - * Do initialization - */ - if (DEBUG (verb)) - fprintf (stderr, "AUTH-PAM: BACKGROUND: INIT service='%s'\n", service); - -#if DLOPEN_PAM - /* - * Load PAM shared object - */ - if (!dlopen_pam (pam_so)) - { - fprintf (stderr, "AUTH-PAM: BACKGROUND: could not load PAM lib %s: %s\n", pam_so, dlerror()); - send_control (fd, RESPONSE_INIT_FAILED); - goto done; - } -#endif - - /* - * Tell foreground that we initialized successfully - */ - if (send_control (fd, RESPONSE_INIT_SUCCEEDED) == -1) - { - fprintf (stderr, "AUTH-PAM: BACKGROUND: write error on response socket [1]\n"); - goto done; - } - - /* - * Event loop - */ - while (1) - { - memset (&up, 0, sizeof (up)); - up.verb = verb; - up.name_value_list = name_value_list; - - /* get a command from foreground process */ - command = recv_control (fd); - - if (DEBUG (verb)) - fprintf (stderr, "AUTH-PAM: BACKGROUND: received command code: %d\n", command); - - switch (command) - { - case COMMAND_VERIFY: - if (recv_string (fd, up.username, sizeof (up.username)) == -1 - || recv_string (fd, up.password, sizeof (up.password)) == -1) - { - fprintf (stderr, "AUTH-PAM: BACKGROUND: read error on command channel: code=%d, exiting\n", - command); - goto done; - } - - if (DEBUG (verb)) - fprintf (stderr, "AUTH-PAM: BACKGROUND: USER/PASS: %s/%s\n", - up.username, up.password); - - if (pam_auth (service, &up)) /* Succeeded */ - { - if (send_control (fd, RESPONSE_VERIFY_SUCCEEDED) == -1) - { - fprintf (stderr, "AUTH-PAM: BACKGROUND: write error on response socket [2]\n"); - goto done; - } - } - else /* Failed */ - { - if (send_control (fd, RESPONSE_VERIFY_FAILED) == -1) - { - fprintf (stderr, "AUTH-PAM: BACKGROUND: write error on response socket [3]\n"); - goto done; - } - } - break; - - case COMMAND_EXIT: - goto done; - - case -1: - fprintf (stderr, "AUTH-PAM: BACKGROUND: read error on command channel\n"); - goto done; - - default: - fprintf (stderr, "AUTH-PAM: BACKGROUND: unknown command code: code=%d, exiting\n", - command); - goto done; - } - } - done: - -#if DLOPEN_PAM - dlclose_pam (); -#endif - if (DEBUG (verb)) - fprintf (stderr, "AUTH-PAM: BACKGROUND: EXIT\n"); - - return; -} |